The 

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 10-K

(Mark One)

For the fiscal year ended December 31, 20162017

OR

For the transition period from            to            

Commission file number: 001-32979

THRESHOLD PHARMACEUTICALS,MOLECULAR TEMPLATES, INC.

(Exact name of registrant as specified in its charter)

(650) 474-8200(512) 869-1555

(Registrant’s telephone number, including area code)

Securities registered pursuant to Section 12(b) of the Act:

Securities registered pursuant to Section 12(g) of the act:Act: None

Indicate by check mark whetherif the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.    Yes  ☐    No  ☒

Indicate by check mark whetherif the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act.    Yes  ☐    No  ☒

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.    Yes  ☒    No  ☐

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files).    Yes  ☒    No  ☐

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K is not contained herein, and will not be contained, to the best of registrant’s knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K.  ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company, or emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company,” and ‘emerging growth company” in Rule 12b-2 of the Exchange Act. (Check one):

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.   ☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).    Yes  ☐    No  ☒

The aggregate market value of the voting and non-voting common equity held by non-affiliates of the Registrantregistrant based upon the closing price of the Common Stock on the NASDAQNasdaq Capital Market on June 30, 20162017 was approximately $42,546,096.$25,999,000, computed based on the closing price of $4.29. The calculation of the aggregate market value of the voting and non-voting common equity held by non-affiliates of the Registrantregistrant excludes shares of Common Stock held by each officer, director and stockholder that the registrant concluded were affiliates on that date. This determination of affiliate status is not necessarily a conclusive determination for other purposes.

On February 28, 2017March 21, 2018 there were 71,591,91827,058,244 shares of the Registrant’sregistrant’s Common Stock outstanding.outstanding.

DOCUMENTS INCORPORATED BY REFERENCE

Portions of the Registrant’sregistrant’s definitive proxy statement for the Registrant’s 2016 Annual Meetingregistrant’s 2018 annual meeting of Stockholdersstockholders to be filed pursuant to Regulation 14A within 120 days of the Registrant’sregistrant’s fiscal year ended December 31, 20162017 are incorporated herein by reference into Part III of this Annual Report on Form 10-K.

Threshold Pharmaceuticals,Molecular Templates, Inc.

TABLE OF CONTENTS

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PART I

Special Note Regarding Forward-Looking Statements

This annual reportAnnual Report on Form 10-K, including the sections entitled “Business,” “Risk Factors,” and “Management’s Discussion and Analysis of Financial Condition and Results of Operations,” contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended or the Securities Act, and Section 21E of the Securities Exchange Act of 1934, as amended or the Exchange Act. We may, in some cases, use words such as “project,” “believe,” “anticipate,” “plan,” “expect,” “estimate,” “intend,” “should,” “would,” “could,” “potentially,” “possible”, “will,” or “may,” or other words that convey uncertainty of future events or outcomes to identify these forward-looking statements. Forward-looking statements may include statements about:

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There are a number of important factors that could cause actualinvolve risks and uncertainties. Actual events or results tomay differ materially from the results anticipated by these forward-looking statements. These important factors include those that we discussdiscussed in this annual report on Form 10-K under the caption “Risk Factors.” You should read these factors and the other cautionary statements made in this annual report on Form 10-K as being applicable to all related forward-looking statements wherever they appear in this annual report on Form 10-K. If one or more of these factors materialize, or if any underlying assumptions prove incorrect, our actual results, performance or achievements may vary materially from any future results, performance or achievements expressed or implied by these forward-looking statements. We undertake no obligation to publicly update any forward-looking statements, whether as a result of new information,various factors. For a more detailed discussion of the potential risks and uncertainties that may impact their accuracy, see the “Risk Factors” section in Part I, Item 1A of this Annual Report on Form 10-K. Given these risks, uncertainties and other factors, you should not place undue reliance on these forward-looking statements. Also, these forward-looking statements reflect our view only as of the date of this report. You should read this report completely and with the understanding that our actual future events or otherwise, exceptresults may be materially different from what we expect. We hereby qualify our forward-looking statements by our cautionary statements. Except as required by law. Unlesslaw, we assume no obligation to update these forward-looking statements publicly, or to update the context requires otherwise,reasons that actual results could differ materially from those anticipated in this annual report on Form 10-Kthese forward-looking statements, even if new information becomes available in the terms “Threshold,” “Threshold Pharmaceuticals,” the “Company,” “we,” “us” and “our” refer to Threshold Pharmaceuticals, Inc. Threshold Pharmaceuticals, Inc., our logo and Metabolic Targeting are our trademarks. Other trademarks, trade names and service marks used in this annual report on Form 10-K are the property of their respective owners.future.

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Overview

We areMolecular Templates, Inc., or Molecular, is a clinical-stage biopharmaceuticaloncology company focused on the discovery and development of differentiated, targeted, biologic therapeutics for cancer. Molecular utilizes its proprietary biologic drug platform to design and generate engineered toxin bodies, or ETBs, which Molecular believes provide a differentiated mechanism of action that may be beneficial in patients resistant to currently available cancer therapeutics. ETBs use a genetically engineered version of the Shiga-like Toxin A subunit, or SLTA, a ribosome inactivating bacterial protein. In its wild-type form, SLT is thought to induce its own entry into a cell when proximal to the cell surface membrane, self-route to the cytosol, and enzymatically and irreversibly shut down protein synthesis via ribosome inactivation. SLTA is normally coupled to its cognate Shiga-like Toxin B subunit, or SLTB, to target the CD77 cell surface marker, a non-internalizing glycosphingolipid. In Molecular’s scaffold, a genetically engineered SLTA subunit with no cognate SLTB component is genetically fused to antibody domains or fragments specific to a cancer target, resulting in a biologic therapeutic that can identify the particular target and specifically kill the cancer cell. The antibody domains may be substituted with other antibody domains having different specificities to allow for the rapid development of new drugs to selected targets in cancer.

ETBs combine the specificity of an antibody with SLTA’s potent mechanism of cell destruction. Based on the disease setting, Molecular has historically used our expertisecreated ETBs that have reduced immunogenicity and are capable of delivering additional payloads into a target cell. Immunogenicity is the ability of a foreign substances to provoke an immune response in a host. ETBs have relatively predictable pharmacokinetic, or PK, and absorption, distribution, metabolism and excretion, or ADME, profiles and can be rapidly screened for desired activity in robust cell-based and animal-model assays. Because SLTA can induce internalization against non- and poorly-internalizing receptors, the tumor microenvironmentuniverse of targets for ETBs should be substantially larger than that seen with antibody-drug conjugates, or ADCs, which are not likely to discoverbe effective if the target does not readily internalize the ADC payload.

ETBs have a differentiated mechanism of cell-kill in cancer therapeutics (the inhibition of protein synthesis via ribosome destruction), and develop therapeuticMolecular has preclinical and diagnosticclinical data demonstrating the utility of these molecules in chemotherapy-refractory cancers. ETBs have shown good safety data in multiple animal models as well as in Molecular’s clinical studies to date. Molecular believes the target specificity of ETBs, their ability to self-internalize, their potent and differentiated mechanism of cell kill and their safety profile provide opportunities for the clinical development of these agents that selectivelyto address multiple cancer types.

Molecular’s initial approach to drug development in oncology involves the selection of lead compounds to validated targets in cancer. Molecular has developed ETBs for various targets, including CD20, CD38, HER2, and PD-L1. CD20 is central to B cell malignancies and is clinically validated as a target tumor cells for the treatment of lymphomas and autoimmune disease. CD38 has been validated as a meaningful clinical target in the treatment of multiple myeloma. PD-L1 is central to immune checkpoint pathways and is a target expressed in a variety of solid tumor cancers. Molecular’s lead compound, MT-3724, is an ETB that recognizes CD20, a B cell marker and is currently in phase I study. The dose escalation portion of its first Phase I clinical trial has been completed for MT-3724 and was followed by the initiation of a Phase Ib expansion cohort, which was initiated Molecular’s fourth fiscal quarter for the fiscal year ended December 31, 2017. Molecular anticipates initiating combination studies with MT-3724 and advancing one or more additional ETBs into clinical trials in 2018.

Molecular has built up multiple core competencies around the creation and development of ETBs. Molecular developed the ETB technology in-house and continues to make iterative improvements in the scaffold and identify new uses of the technology. Molecular also developed the proprietary process for manufacturing ETBs under Good Manufacturing Process, or GMP standards and continues to make improvements to its manufacturing processes. Molecular has conducted multiple GMP manufacturing runs with its lead compound and believes this process is robust and could support commercial production with gross margins that are similar to those seen with antibodies.

Challenges in Oncology

Existing mechanisms of action, the specific biochemical interaction through which a drug substance produces its pharmacological effect, are subject to numerous limitations in oncology. The clinical benefit of a given drug is a function of the biological properties of the drug, the target with which the drug interacts and the tumor indication being treated, but the relative contribution of each of these factors is difficult to separate. To date, significant

challenges exist in identifying the most appropriate cancer targets, applying the most effective mechanisms of action and selecting the appropriate disease indications and most responsive patient populations for a particular drug. These challenges, including the following:

Molecular’s Differentiated Approach

Molecular was founded on the principle that differentiated mechanisms of action are crucial for improving outcomes in oncology. Molecular has created a new ETB scaffold with a differentiated mechanism of action, coupled with a predictable PK and ADME profile. Molecular’s ETB scaffold permits rapid screening for lead identification and easily scalable production, which Molecular believes offers an opportunity to provide meaningful clinical benefits in oncology with more cost efficient research and development than current treatments. Molecular believes the differentiated biological activity inherent to the ETB scaffold, particularly the ability to induce internalization and employ a differentiated mechanism of cell kill, may allow for differentiated clinical benefit in patients livingas monotherapy and in combination with cancer. Most recently, westandard of care therapies.

Molecular likens the extensive de-immunization work it has conducted on SLTA to the chimerization of monoclonal antibodies. Monoclonal antibody chimerization is a process for reducing immunogenicity when an antibody from one species is introduced into a different species. Chimerization has allowed for the wide-spread use of antibodies as human therapeutics across multiple disease settings. Molecular believes that the de-immunization of SLTA may allow for ETB use across multiple indications in oncology, including solid tumors, as well as other potential non-oncology indications.

Molecular has seen in both preclinical models and in its Phase I trials to date that the differentiated mechanism of action employed by its ETBs can be effective in chemo-resistant tumor cells. Molecular believes this creates the potential for a rapid characterization of efficacy in carefully designed clinical trials in relapsed and refractory settings, particularly when targeting tumor markers that persist after treatment with multiple lines of therapy and whose targeting has been shown to provide a survival benefit. Molecular also has seen preclinically that its ETBs can have devoted substantiallyadditive or synergistic activity in combination with a number of small molecule agents including chemotherapeutics, immunomodulatory agents and tyrosine kinase inhibitors. Molecular believes that the ability of ETBs to be additive or synergistic to a variety of current treatments may allow for combination therapy in earlier lines of disease.

Molecular believes it can develop ETBs against well-validated targets and new targets, enabling a phenotypically based clinical trial design that may result in shorter development timelines with lower associated costs. More specifically:

Molecular’s Strategy

Molecular’s goal is to bring the right ETBs to the right patients to provide long-lasting benefits that ultimately improve patients’ lives. To achieve its goal, Molecular is:

Molecular’s Engineered Toxin Body (ETB) Platform Technology

Although chemotherapy remains the cornerstone of treatment for most cancers, the advent of new and targeted classes of therapies has dramatically changed outcomes in the treatment of disease. The advent of monoclonal antibodies, signal transduction inhibitors and, most recently, immune-oncologics have provided substantial clinical benefit in both the relapsed and refractory setting and, when used in combinations, in earlier lines of therapy.

Molecular believes that ETBs represent a new class of targeted agents with differentiated biology that are well-positioned to improve outcomes in cancer patients.

ETBs appear to induce the internalization of non- or poorly-internalizing targets, have a differentiated mechanism of action (enzymatic and irreversible ribosome inactivation), have relatively predictable PK and ADME profiles and can be readily manufactured to GMP standards. From a library of antibody targeting domains, Molecular’s research and design platform allows for the comprehensive (six to eight weeks) in vitro selection of a lead ETB to a given target based on hypoxia-activated prodrugaffinity and specificity, potency and expression. Lead selection is confirmed through the use of animal models to verify PK, ADME and potency. ETBs possess potent direct cell killing effects via a differentiated mechanism of action, can force receptor internalization, and can be used to deliver payloads such as foreign class I antigen to the cytosol. MT-3724, Molecular’s lead ETB candidate, is being developed for treating B-cell malignancies and utilizes the wild-type SLTA. Because of the immune-compromised nature of patients with B-cell malignances, Molecular did not believe de-immunization of SLTA was critical in these patients; this hypothesis has been supported by clinical data in DLBCL patients.

In subsequent ETBs, Molecular utilizes a highly potent and proprietarily de-immunized SLTA scaffold that elicits significantly reduced innate and adaptive immunogenic responses as demonstrated in preclinical and animal studies (presented at the 2017 American Association for Cancer Research, or AACR, Annual Meeting). For indications where tumors have been demonstrated to be sensitive to T-cell engagement, Molecular has developed ETBs that deliver foreign class I viral antigens for presentation on the surface of the tumor: Molecular’s Antigen Seeding Technology (AST), a differentiated approach to immune-oncology. Molecular is currently building out animal models to further validate and screen ETB candidates support this approach.

Molecular believes that its proprietary ETB technology platform represents a differentiated approach in oncology. ETBs possess the targeting specificity of antibody-based therapeutic approaches but deliver highly potent payloads that disrupt protein synthesis, a fundamental function of a cancer cell, in a manner not subject to traditional chemotherapy resistance mechanisms or target internalization limitations, as with ADCs. Molecular is also seeking to expand the universe of potential targets subject to pharmaceutical treatments by exploiting the ETB’s ability to force internalization against receptors that do not normally internalize to. MT-3724 highlights this capability and approach. MT-3724 targets CD20, which is a canonical non-internalizing receptor that is not susceptible to traditional chemo-based ADC approaches.

Novel mechanisms of action are needed in oncology treatment, and Molecular believes that its ETB platform technology’s differentiated mechanisms of action may offer unique benefits over existing treatment modalities.

ETB Product Pipeline

Molecular is developing a pipeline of ETBs that Molecular believes will provide a meaningful and long-lasting benefit to cancer patients. Molecular plans to develop each of these as single agents and/or in combination with other therapies, as applicable. The following table depicts Molecular’s current pipeline:

MT-3724—ETB Targeting CD20

Overview

CD20 is expressed on 90% of B-cell non-Hodgkin’s lymphoma, or NHL, cells and is a non-internalizing receptor. Rituxan (rituximab), an antibody to CD20, is approved for treatment of NHL in both the front and second-line settings. Rituxan has limited direct cell-kill effects against CD20-expressing cells. Instead, it works through indirect methods of recruiting immune responses to CD20-expressing cells through antibody dependent cell-mediated cytotoxicity, or ADCC, and/or complement dependent cytotoxicity, or CDC. Rituxan’s indirect cell-kill mechanism’s reliance on a favorable tumor microenvironment for immune stimulation is problematic because it allows opportunities for resistance to emerge. Therefore, direct cell-kill approaches that target CD20-expressing lymphomas are attractive. Two such agents are currently approved: the radioisotope-conjugated antibodies Bexxar, developed by GlaxoSmithKline, and Zevalin, developed by IDEC Pharmaceuticals (now part of Biogen), both of which use ionizing radiation to induce direct cell-kill without internalization being necessary. These radioisotope conjugated antibodies are more effective than naked anti-CD20 antibody approaches such as Rituxan and HuMax-CD20 in the clinic: evofosfamiderelapsed or refractory indolent NHL setting because they are far less dependent on the physiology of the tumor. However, despite their favorable efficacy profile, Bexxar and tarloxotinib;Zevalin are considered commercial

disappointments and have not been widely adopted by oncologists primarily due to the constraints associated with the administration of nuclear medicines. Radioimmunotherapies are difficult to administer, with few institutions licensed for nuclear medicine. Because of these factors, the combined use of Bexxar and Zevalin accounted for only a lesser extent [18F]-HX4, our imaging agent product candidate.minimal share of all administered second-line therapies for indolent NHL patients worldwide (seven major markets) despite superior clinical data in this setting. Bexxar was subsequently taken off the market in 2013. Molecular believes this provides a significant opportunity for a CD20-targeting therapy, such as MT-3724, that directly kills cells without the use of radioisotopes, and utilizes a mechanism of action of cell kill that is not subject to cross-resistance with chemotherapy or antibody approaches.

Evofosfamide Investigational Hypoxia-Activated Prodrug

In December 2015, we announced topline results from two pivotalMT-3724 is a ETB specific to the B-cell marker CD20 protein. Molecular developed MT-3724 to provide a non-radioactive means of direct cell-kill targeted to CD20 for the treatment of NHL. The differentiated mechanism of action of MT-3724 involves binding to the surface protein CD20, forcing internalization into the target cell, retrograde transport to the cytosol and subsequent enzymatic and permanent ribosome-inactivation. Following the completion of the Phase 3 clinical trialsI dose escalation trial in 2017, Molecular is currently conducting a Phase Ib expansion trial of evofosfamide: TH-CR-406 conducted by ThresholdMT-3724 in patients with soft tissue sarcomarelapsed/refractory DLBCL. Molecular is also planning to initiate two MT-3724 studies in earlier lines of DLBCL in 2018, one in combination with chemotherapy and MAESTRO conductedthe other in combination with Revlimid.

Preclinical Overview

MT-3724 is a fusion protein which is comprised of the variable regions of the heavy (VH) and light chains (VL) of an anti-CD20 antibody connected with a short linker peptide (Figure 1) that make up a single-chain variable fragment, or scFv. This binding domain is genetically fused to a proprietarily engineered form of SLTA. Because MT-3724 lacks the fragment crystallizable, or Fc, portion of an intact antibody, MT-3724 does not rely on host ADCC, CDC, or complement-mediated lysis to induce cell death. Naked antibody therapies rely on the induction of ADCC/CDC as the primary mechanisms of indirect cell-kill. Thus, Molecular believes MT-3724 may avoid the mechanisms of lymphoma cell resistance that occurs with the currently available anti-CD20 antibodies.

The three key biological properties of MT-3724 that reflect the differentiated biology of ETBs include:

In binding experiments, MT-3724 bound selectively to CD20+ expressing cell lines with specificity and affinity similar to Rituxan. MT-3724 gains entry into target cells through CD20-dependent binding. The binding of MT-3724 to CD20 is a critical step in cellular cytotoxicity induced by Merck KGaA, Darmstadt, Germany (“, or Merck KGaA”), MT-3724.

In Vivo Results

MT-3724 has demonstrated potent and specific activity against a wide panel of CD20 expressing cancer cell lines, including Rituxan refractory patient samples. In addition to in patientsvitro activity, Molecular has evaluated MT-

3724 in a series of preclinical efficacy models that show its potent activity in destroying CD20 expressing human tumors. MT-3724 was generally well tolerated in these animal models. In one model, tumor responses were measured on Days 5, 10, 15 and 20 by bioluminescent imaging of Raji-luc tumors as shown in Figure 2. Treatment with advanced pancreatic cancer;MT-3724 was well tolerated and that neither trial met its primary endpoint of demonstratingresulted in a statistically significant improvementsurvival advantage in overall survivalthis model..  Of particular note based on

Molecular performed a study to determine the data fromtherapeutic potential of MT-3724 to inhibit the September 1, 2015 cut-off date for the MAESTRO trial,growth of CD20-expressing human lymphoma cells in a meaningful improvementsubcutaneous implant model in overall survivalathymic nude mice. Molecular observed a significant anti-tumor response in MT-3724 treated mice. Specifically, administration of MT-3724 at both 2 mg/kg/dose and 4 mg/kg/dose demonstrated cytotoxic activity against human lymphoma cells in this xenograft tumor model, as shown in Figure 3. Treatment with MT-3724 was reported for a subgroup of 123 Asian patients (enrolled at Japanese and South Korean sites) in which the risk of death was reduced by 48 percent for patients on the treatment arm compared to patients on the control arm. The hazard ratio (“HR”) for this subgroup was 0.52 (95% confidence interval (or “CI”: 0.32 – 0.85).  In particular and based upon Merck KGaA’s MAESTRO data, the 116 patients from Japan from the treatment arm had a median overall survival of 13.6 months versus 9.1 months for those patients on the control arm with significant improvements in progression free survival, objective response rates, and reductionsgenerally well tolerated in the pancreatic cancer biomarker, CA19-9. No new safety findings were identified in the MAESTRO study and the safety profile was consistent with that previously reported in other studies of evofosfamide plus gemcitabine. Based on the results of our analyses, we discussed potential registration pathways with Japan’s Pharmaceuticals and Medical Devices Agency (PMDA).  In March 2017, we received minutes from the Company’s formal meeting with the PMDA indicating that the Company’s analysis of the data from the randomized Phase 3 study, EMR200592-001 (N=693), conducted under a Special Protocol Agreement with the FDA, and the data from the supporting randomized Phase 2 study, TH-CR-404 (N=214),would not provide adequate efficacy data to support the submission of a New Drug Application (“JNDA”) for evofosfamideanimals.

Clinical Overview

MT-3724 is being developed for the treatment of patients with locally advanced unresectablerelapsed or metastatic pancreatic adenocarcinoma previously untreated with chemotherapy.  We are currently in discussions with the PMDA to clarify the scope of a new clinical trial for which the PMDA would consider necessary to accept a JNDA for evofosfamide in Japan based on the previous results observed in the Japanese sub-population.  Our current evofosfamide development strategy is limited to the Company-sponsored Phase 1 clinical trial of evofosfamide in combination with immune checkpoint antibodies in collaboration with researchers and clinicians at The University of Texas MD Anderson Cancer Center, initiated March 1, 2017 and investigator-sponsored clinical trials of evofosfamide in combination with antiangiogenic therapies in a variety of tumor types as described in more detail below under “Our Product Candidates.”  

Tarloxotinib Investigational Hypoxia-Activated EGFR Tyrosine Kinase Inhibitor

Our second product candidate, tarloxotinib, was a prodrug designed to selectively release a covalent (irreversible) EGFR tyrosine kinase inhibitor under hypoxic conditions. In September 2016, the Company announced that its Phase 2 proof-of-concept trial evaluating tarloxotinib bromide for the treatment of patients with mutant EGFR-positive, T790M-negative advanced non-small cell lung cancer (NSCLC) progressing on an EGFR tyrosine kinase inhibitor (TH-CR-601) did not achieve its primary interim response rate endpoint. While the Company’s other Phase 2 proof-of-concept trial evaluating tarloxotinib bromide for the treatment of patients with recurrent or metastatic squamous cell carcinomas of the skin met its primary interim response rate endpoint, the other two arms of the study, evaluating tarloxotinib bromide for the treatment of patients with recurrent or metastatic squamous cell carcinomas of the head and neck did not achieve their primary interim response rate endpoint, and the overall results from the two trials didn't meet the activity thresholds required to justify further development investment by the Company. Accordingly, no further clinical development is planned. We plan to present preliminary results from both trials at an upcoming medical meeting.

[18F]-HX4 Investigational PET Imaging Agent for Hypoxia

Our third product candidate, [18F]-HX4 [flortanidazole (18F)] is an investigational Positron Emission Tomography (PET) imaging agent for hypoxia developed by Siemens Healthcare Molecular Imaging to potentially identify and quantify the degree of hypoxia in tumors in vivo. In view of the results of both Phase 3 trials of evofosfamide and both Phase 2 trials of tarloxotinib as described above, no further clinical development is planned.

Our Current Strategy

Our goal is for Threshold to be a leader in the development and commercialization of novel therapeutics for serious unmet needs in oncology. Inrefractory NHL who have failed one element of our strategy, the board of directors approved in December 2015 a plan to explore strategic alternatives

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to further realize value from the Company's pipeline assets while preserving the Company's cash balance to the extent practicable.  Also in December 2015 and September 2016, the Company completed reductions in force of employees designed to reduce operating expenditures, reduce infrastructure costs and improve efficiency of quality-related activities while exploring strategic alternatives.  In August 2016, the Company retained financial advisors, to assist in the process of evaluating strategic alternatives.  The Company, working with financial and legal advisors, conducted a process of identifying and evaluating potential strategic alternatives, including potential acquisitions, mergers, strategic partnerships and other strategic transactions.  

On March 16, 2017, the “Company entered into an Agreement and Plan of Merger and Reorganization (the “Merger Agreement”) with Molecular Templates, Inc., a Delaware corporation (“Molecular Templates”), a clinical-stage biopharmaceutical company focused on the development and commercialization of innovative therapeutics to treat cancer, and Trojan Merger Sub, Inc., a Delaware corporation and wholly-owned subsidiary of the Company (“Merger Sub”).  Upon the terms and subject to the satisfaction of the conditions described in the Merger Agreement, including approval of the transaction by the Company’s stockholders and Molecular Templates’ stockholders, Merger Sub will be merged with and into Molecular Templates (the “Merger”), with Molecular Templates surviving the Merger as a wholly-owned subsidiary of the Company. The Merger is intended to qualify as a tax-free reorganization for U.S. federal income tax purposes.  

At the effective time of the Merger (the “Effective Time”): (a) each share of Molecular Templates common stock outstanding immediately prior to the Effective Time (excluding shares held by the Company, Merger Sub or Molecular Templates and dissenting shares, and after giving effect to the purchase or conversion rights of Molecular Templates’ preferred stockholders, warrant holders and noteholders) will be converted solely into the right to receive a number of shares of Company Common Stock (the “Shares”) equal to the exchange ratio described below, and (b) each outstanding Molecular Templates stock option will be assumed by the Company. Under the exchange ratio formula in the Merger Agreement, the former Molecular Templates security holders immediately before the Merger are expected to own approximately 65.6% of the aggregate number of the Shares, and the stockholders of the Company immediately before the Merger are expected to own approximately 34.4% of the aggregate number of the Shares, subject to certain assumptions (on a fully diluted basis). Further, this exchange ratio will be adjusted to the extent the Company’s net cash (as defined in the Merger Agreement) at closing of the merger (the “Closing”) is greater than $17.5 million or less than $12.5 million.

Following the Closing, Molecular Templates’ Chief Executive Officer, Eric Poma, Ph.D., will become the Company’s Chief Executive Officer, and the Company’s corporate headquarters will be relocated Austin, Texas. Additionally, following the Closing, the board of directors of the Company (the “Company Board”) will consist of seven directors and will be comprised of (i) two members designated by Molecular Templates, (ii) two members of the current Company Board, including Harold E. Selick, who will act as chairman, and (iii) three members mutually agreed upon by Molecular Templates and the Company.  In addition, following the Closing, the Company will change its name to Molecular Templates, Inc. and will change its NASDAQ symbol to MTEM.

The Merger Agreement contains customary representations, warranties and covenants made by the Company and Molecular Templates, including covenants relating to obtaining the requisite approvals of the stockholders of the Company and Molecular Templates, indemnification of directors and officers, the Company’s and Molecular Templates’ conduct of their respective businesses between the date of signing of the Merger Agreement and the Closing and to prepare and file a registration statement on Form S-4 that will contain a proxy statement / prospectus / information statement to register the Shares issued pursuant to the Merger Agreement (the “S-4”).

In connection with the Merger and the S-4, the Company will be seeking the approval of the Company’s stockholders with respect to certain actions, including the following:

The Closing is subject to satisfactionchemotherapeutics and anti-CD20 antibody therapies and for whom all other approved therapies (biologic, chemotherapeutic or waiver of certain conditions including, among other things, (i) the expiration or termination of any waiting period applicable to the consummation of the Merger under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, (ii) the accuracy of the representations and warranties, subject to certain materiality qualifications, (iii) compliance by the parties with their respective covenants, (iv) no law or order preventing the Merger and related transactions, and (v) the effectiveness of the S-4.  The Closing is not contingent upon the completion of the Financing described below.

The Merger Agreement also includes termination provisions for both the Company and Molecular Templates. In connection with a termination of the Merger Agreement under specified circumstances involving competing transactions, a willful, intentional and

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material breach of the non-solicitation obligations, a change in the board of directors’ recommendation of the Merger to the stockholders or other triggering events, either party may be required to pay the other party a termination fee of $750,000, plus reimbursement for certain fees and expenses.

In connection with execution of the Merger Agreement, the Company made a bridge loan to Molecular Templates pursuant to a note purchase agreement and promissory notes (the “Notes”) up to an aggregate principal amount of $4.0 million with an initial closing that was held on March 24, 2017 for a principal amount of $2.0 million.  If the Merger Agreement is terminated prior to the to the maturity date of the Notes, the outstanding principal of the Notes plus all accrued and unpaid interest shall become due and payable upon the earlier of (i) the consummation of a qualified financing by Molecular Templates of at least $10.0 million, (ii) the occurrence of a Molecular Templates liquidity event, or (iii) the four-month anniversary of the termination of the Merger Agreement, and such amounts shall be credited against any termination fees owed by the Company to Molecular Templates pursuant to the Merger Agreement.

Concurrently with the execution of the Merger Agreement, officers and directors of the Company entered into support agreements with Molecular Templates relating to the Merger covering approximately 1.2% of the outstanding Shares, as of immediately prior to the Merger (the “Company Support Agreements”). The Company Support Agreements provide, among other things, that the stockholders to the Company Support Agreement will vote all of the Shares held by them in favor of the issuance of the Shares in connection with the Merger and the amendments to the Company’s certificate of incorporation contemplated by the Merger Agreement.

Concurrently with the execution of the Merger Agreement, officers, directors and certain stockholders of Molecular Templates entered into support agreements with the Company covering approximately 96.3% of the outstanding shares of Molecular Templates (including shares of its preferred stock on an as-converted to common stock basis) relating to the Merger (the “Molecular Templates Support Agreements,” and together with the Company Support Agreement, the “Support Agreements”). The Molecular Templates Support Agreements provide, among other things, that the officers and stockholders party to the Molecular Templates Support Agreement will vote all of the shares of Molecular Templates held by them in favor of the adoption of the Merger Agreement, the approval of the Merger and the other transactions contemplated by the Merger Agreement.

Concurrently with the execution of the Merger Agreement, officers and directors of the Company entered into lock-up agreements (the “Company Lock-Up Agreement”), pursuant to which they accepted certain restrictions on transfers of the Shares for the 180-day period following the Effective Time. Concurrently with the execution of the Merger Agreement, officers, directors and certain stockholders of Molecular Templates, have entered into lock-up agreements (the “Molecular Lock-Up Agreement,” and together with the Company Lock-Up Agreement, the “Lock-Up Agreements”), pursuant to which they accepted certain restrictions on transfers of the Shares for the 180-day period following the Effective Time.

Although we have entered into the Merger Agreement and intend to consummate the merger, there is no assurance that we will be able to successfully consummate the merger on a timely basis, or at all.

In addition on March 16, 2017, the Company and Molecular Templates received from Longitude Venture Partners III, L.P. (“Longitude”) an Equity Commitment Letter (the “Commitment Letter”), pursuant to which, immediately following the Closing of the Merger, Longitude will purchase $20 million of equity securities in the Company.  Longitude’s investment is subject to certain conditions, including the Closing of the Merger and the Company having secured commitments from additional investors for the purchase of an additional $20 million of such securities (the “Financing”).  The Financing will be accomplished in a private placement exempt from registration under Section 4(a)(2) and Regulation D under the Securities Act of 1933, as amended (the “Securities Act”), and the rules promulgated thereunder. The securities to be sold in the Financing have not been registered under the Securities Act, or any state securities laws, and may not be offered or sold in the United States except pursuant to an exemption from, or in a transaction not subject to, the registration requirements of the Securities Act and applicable state securities laws.  The closing of the Merger is not contingent upon the completion of this Financing.

In November 2016, the Company received a deficiency letter from the Listing Qualifications Department (the “Staff”) of The NASDAQ Stock Market notifying the Company that, for the last 30 consecutive business days, the bid price for the Company’s common stock had closed below the minimum $1.00 per share requirement for continued inclusion on The NASDAQ Global Market pursuant to NASDAQ Listing Rule 5450(a)(1) (the “Rule”). In accordance with NASDAQ Listing Rule 5810(c)(3)(A), the Company was provided an initial period of 180 calendar days, or until May 10, 2017, to regain compliance with the Rule. If, at any time before May 10, 2017, the bid price for the Company’s common stock closes at $1.00 or more for a minimum of 10 consecutive business days as required under Listing Rule 5810(c)(3)(A), the Staff would provide written notification to the Company that it complies with the Rule.  In March 2017, the Company’s board of directors approved a reverse stock split, within a range which shall be no less than 5:1 or more than 15:1 of the Company’s common and preferred stock, which would be contingent upon shareholder approval of the Merger and the stock split.

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If the Merger is not completed, the Company will reconsider strategic alternatives and could pursue one of the following courses of action:

Our Product Candidates

Evofosfamide Investigational Hypoxia-Activated Prodrug

The introduction of therapies that preferentially target tumor hypoxia offers the potential to deliver cancer therapies selectively to tumor tissue and to expand the therapeutic options available for cancer patients across the majority of tumor types. Evofosfamide is designed as a prodrug that is preferentially activated under the extreme hypoxic conditions commonly found in tumors, but not typically in healthy tissues. Within regions of tumor hypoxia, evofosfamide is converted to its active form, bromo-isophosphoramide mustard (Br-IPM). Variants of IPM are clinically validated potent DNA alkylating agents, which kill tumor cells by causing DNA to crosslink thereby rendering cells unable to replicate their DNA and divide. Once activated in hypoxic tissues, Br-IPM may also diffuse into surrounding oxygenated regions of the tumor and kill cells there via a “bystander effect”.

Preclinical and clinical data suggest that evofosfamide has significant antitumor activity both alone as well as in combination with other cancer therapies that target the rapidly proliferating cells found in normally oxygenated regions of solid tumors. Preclinical studies have also shown enhanced antitumor activity of evofosfamide when combined with antiangiogenic agents, which are drugs designed to disrupt the blood vessel network supplying tumors. The underlying biological rationale for this enhanced activity is based, in part, on evidence that antiangiogenic agents increase levels of tumor hypoxia. Other research suggests that the bone marrow of patients with leukemia as well as multiple myeloma is also highly hypoxic and supports the potential therapeutic utility of evofosfamide in treating these blood cancers.

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Evofosfamide Clinical Development Program Overview

The current development plan for evofosfamide is focused on analyzing the MAESTRO biomarker data for the purposes of pursuing potential registration pathways in pancreatic cancer with regulatory authorities and potential partners   In addition, we will develop evofosfamide in combination with immune checkpoint antibodies in collaboration with researchers and clinicians at The University of Texas MD Anderson Cancer Center, initiated March 1, 2017.  Further, we will continue developing evofosfamide in combination with antiangiogenics, and as a monotherapy in investigator sponsored and cooperative group clinical trials as supported by preclinical and clinical data and where there is high unmet need for new anticancer agents. To date, evofosfamide has been evaluated in more than 1600 patients with cancer.

We completed a monotherapy, Phase 1 clinical trial that determined the maximum tolerated dose, dose limiting toxicities, safety, pharmacokinetics and preliminary efficacy of evofosfamide monotherapy in patients with advanced solid tumors. We expanded enrollment in this trial to investigate evofosfamide as a single agent in specific indications in which monotherapy activity had been observed as well as in some indications in which notable activity had been documented in combination with other chemotherapy drugs. We completed enrollment in two combination therapy Phase 1/2 clinical trials that determined the maximum tolerated doses, dose-limiting toxicities, safety, pharmacokinetics and preliminary efficacy of evofosfamide in combination with four currently approved chemotherapies. Data from this collection of clinical trials supported our initial randomized controlled trial of evofosfamide in first-line pancreatic cancer.

The most advanced clinical trials of evofosfamide conducted to date were two pivotal Phase 3 clinical trials: one in combination with doxorubicin versus doxorubicin alone in patients with soft tissue sarcoma, and the other in combination with gemcitabine versus gemcitabine plus placebo in patients with advanced pancreatic cancer. Initiation of those Phase 3 clinical trials was supported by preclinical data in disease-specific models as well as data from Phase 2 clinical trials in the same patient populations.

In December 2015, we announced topline results from both Phase 3 clinical trials of evofosfamide, reporting that neither trial met its primary endpoint of improving overall survival with statistical significance.

In March 2016, we and Merck KGaA agreed to terminate our former collaboration with Merck KGaA, and all rights to evofosfamide were returned to us. As a result, we will not receive any clinical development milestones or any other funding from Merck KGaA for the purpose of conducting any further clinical development of evofosfamide. Under our former collaboration with Merck KGaA, Merck KGaA was responsible for 70% of the worldwide development expenses for evofosfamide. Our ability to advance the clinical development of evofosfamide is dependent upon our ability to enter into new collaborative or partnering arrangements for evofosfamide, or to otherwise obtain sufficient additional funding for such development.  Accordingly, at this time in 2017 we currently only plan to analyze biomarker data from the MAESTRO trial for the purposes of pursuing discussions of development in pancreatic cancer with regulatory authorities and potential partners, continue the Company-sponsored Phase 1 clinical trial of evofosfamide in combination with immune checkpoint antibodies in collaboration with researchers and clinicians at The University of Texas MD Anderson Cancer Center, initiated March 1, 2017;  as well as to continue investigator sponsored studies of evofosfamide in combination with antiangiogenics.

Outcome and Status of Evofosfamide Program in Pancreatic Cancer

In December 2012, Merck KGaA opened the global pivotal Phase 3 MAESTRO clinical trial assessing the efficacy and safety of evofosfamide in combination with gemcitabine in patients with previously untreated, locally advanced unresectable or metastatic pancreatic adenocarcinoma. MAESTRO stands for evofosfamide in the treatment of MetastAtic or unrESectable pancreaTic adenocaRcinOma.

The MAESTRO trial was a randomized, placebo-controlled, international, multi-center, double-blind Phase 3 clinical trial of evofosfamide plus gemcitabine compared with placebo plus gemcitabine conducted by Merck KGaA. In November 2014, we announced that Merck KGaA completed the target enrollment of 660 patients in the trial. The primary efficacy endpoint was OS; the secondary endpoints included efficacy measured by progression-free survival, or PFS, overall response rate and disease control rate, as well as assessments of safety and tolerability, pharmacokinetics and biomarkers. The study was being conducted under a Special Protocol Assessment, or SPA, agreement with the FDA.

In December 2015, we announced top-line results based on Merck KGaA’s analysis that patients treated with evofosfamide in combination with gemcitabine did not demonstrate a statistically significant improvement in OS compared with gemcitabine plus placebo. In January 2016 at the American Society of Clinical Oncology 2016 Gastrointestinal Cancers Symposium (ASCO GI), Merck KGaA’s analyses of the results from the Phase 3 MAESTRO trial were presented. Median OS was 8.7 months for patients treated with evofosfamide plus gemcitabine and 7.6 months for patients treated with placebo plus gemcitabine (HR: 0.84; 95% CI: 0.71 - 1.01; p=0.0589). The survival on the control arm was higher than the 6 to 7 months reported in other randomized controlled trials. While the primary efficacy endpoint of overall survival narrowly missed statistical significance, efficacy endpoints of progression-free survival

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and confirmed overall response rates demonstrated significant improvements for patients treated with the combination of evofosfamide and gemcitabine (the “treatment arm”) compared to gemcitabine plus placebo (the “control arm”) including PFS and objective response rate, or ORR. For patients treated with evofosfamide plus gemcitabine, median PFS was longer (5.5 vs. 3.7 months; HR 0.77; 95% CI: 0.65- 0.92; p=0.004) and confirmed ORR was higher (15.2% vs. 8.6%; Odds ratio = 1.90; 95% CI: 1.16-3.12; p=0.009). Of particular note, a meaningful improvement in overall survival was reported for a subgroup of 123 Asian patients (enrolled at Japanese and South Korean sites) in which the risk of death was reduced by 42 percent for patients on the treatment arm compared to patients on the control arm. The hazard ratio, (or “HR”), for this subgroup was 0.58 (95% confidence interval (or “CI”: 0.36 – 0.93).  In particular and based upon Merck’s MAESTRO data, the 116 patients from Japan from the treatment arm had a median overall survival of 13.6 months versus 9.1 months for those patients on the control arm with significant improvements in progression free survival, objective response rates, and reductions in the pancreatic cancer biomarker, CA19-9. No new safety findings were identified in the MAESTRO study and the safety profile was consistent with that previously reported in other studies of evofosfamide plus gemcitabine. . Grade 3/4 hematologic adverse events were more frequent with evofosfamide plus gemcitabine, which is consistent with the safety profile in other studies.

Based on the results of our analyses, we discussed potential registration pathways with Japan’s Pharmaceuticals and Medical Devices Agency (PMDA).  On March16, 2017, we received minutes from the Company’s formal meeting with the PMDA indicating that the Company’s analysis of the data from the randomized Phase 3 study, EMR200592-001 (N=693), conducted under a Special Protocol Agreement with the FDA, and the data from the supporting randomized Phase 2 study, TH-CR-404 (N=214),would not provide adequate efficacy data to support the submission of a New Drug Application (“JNDA”) for evofosfamide for the treatment of patients with locally advanced unresectable or metastatic pancreatic adenocarcinoma previously untreated with chemotherapy.  We are currently in discussions with the PMDA to clarify the scope of a new clinical trial for which the PMDA would consider necessary to accept a JNDA for evofosfamide in Japan based on the previous results observed in the Japanese sub-population.

The MAESTRO trial was initiated following results from a randomized, controlled Phase 2b clinical trial of evofosfamide in combination with gemcitabine in patients with first-line pancreatic cancer (which we refer to as the 404 trial). A total of 214 patients with previously untreated, locally advanced, unresectable or metastatic pancreatic adenocarcinoma were enrolled and treated in the clinical trial at 45 sites in the U.S. Patients were randomized equally into one of three cohorts: evofosfamide at a dose of 240 mg/m² plus gemcitabine or evofosfamide at a dose of 340 mg/m² plus gemcitabine or gemcitabine alone. If a patient’s cancer progressed while on gemcitabine alone, the patient could crossover and be randomized into one of the evofosfamide plus gemcitabine cohorts. The primary efficacy endpoint of the trial was a comparison of progression-free survival between the two pooled combination arms and the gemcitabine alone arm. The secondary endpoints were overall response rate, overall survival, event-free survival, CA 19-9 (a serum biomarker) response rate as well as various safety parameters.

In February 2012, we announced top-line results that the primary endpoint in the 404 trial was achieved, showing a median progression-free survival of 5.6 months for patients treated with the combination of evofosfamide at 240 mg/m² and 340 mg/m² compared with 3.6 months for patients treated with gemcitabine alone. The progression-free survival hazard ratio comparing the evofosfamide combinations to gemcitabine alone was 0.61 (95% CI: 0.43 – 0.87), which was highly statistically significant (p=0.005). Final results of the 404 trial were published in the December 15, 2014 issue of the Journal of Clinical Oncology and were consistent with previously-reported results. The final results from the 404 trial showed a consistent dose effect in terms of improved progression-free survival, increased objective response rate, and decreased CA 19-9 levels in the gemcitabine plus evofosfamide (340 mg/ m²) arm compared with the gemcitabine plus evofosfamide (240 mg/ m²)  and the gemcitabine-alone arms. There was a significant improvement (p=0.008) in progression-free survival associated with a 41% reduction of risk for disease progression or death for patients treated with gemcitabine plus evofosfamide (340 mg/ m²). This represented a 2.4-month increase in median progression-free survival for patients receiving gemcitabine plus evofosfamide (340 mg/ m²) compared with gemcitabine alone. The 12-month overall survival rates were also in favor of the gemcitabine plus evofosfamide (340 mg/ m²) treatment group compared with the control arm (38% vs. 26% (p=0.13)). Median overall survival for gemcitabine, gemcitabine plus evofosfamide (240 mg/ m²), and gemcitabine plus evofosfamide (340 mg/ m²) was 6.9, 8.7, and 9.2 months, respectively; the differences between treatment groups were not significant, which may be at least partially explained by control arm patients with progressive disease crossing over to one of the gemcitabine plus evofosfamide treatment arms. In other words, we believe that patients receiving gemcitabine alone who crossed over to receive gemcitabine plus evofosfamide upon disease progression contributed to the survival of the control arm. The improvement in median overall survival in the gemcitabine plus evofosfamide treatment arms was consistent with the improvement in median progression-free survival. The most common nonhematologic adverse events were fatigue, nausea and peripheral edema, and were similar in frequency across treatment groups. Skin and mucosal toxicities, predominantly Grade 1 and 2, and myelosuppression, were the most common adverse events related to evofosfamide and did not result in increases in treatment discontinuation. Adverse events leading to discontinuation of study treatment as well as serious adverse events were balanced across all treatment arms. All other severe adverse events were generally below 10%. There was no significant difference in the percentage of patients discontinuing treatment for adverse events across the three treatment arms.

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Evofosfamide Program with immune checkpoint antibodies

Research has shown that hypoxia contributes to the immunosuppressive microenvironment of solid tumors and therefore may result in resistance to immune checkpoint inhibitors. This is related to the fact that suppressive cells such as myeloid-derived suppressor cells (MDSCs) preferentially reside in the hypoxic regions of tumors (Ai et al 2015; Chiu et al. 2016; Chouaib et al. 2016) and because effector T cells are preferentially excluded from hypoxic regions (Marotta et al. 2011; Curran et al. 2015). Additionally, the tumorstem cell death induced by evofosfamide may result in greater availability of tumor antigen for uptake and presentation by dendritic cells.

Preclinical research at the M.D. Anderson Cancer Center (MDACC) in the laboratory of Dr. Michael Curran demonstrating strong additive anticancer effects when combining evofosfamide with immune checkpoint inhibitors in syngeneic animal models (Ai et al 2015) has led to the development of a Phase 1 study evaluating evofosfamide in combination with ipilimumab in patients with histologically-confirmed metastatic or locally advanced prostate cancer, metastatic pancreatic cancer, melanoma or HPV-negative squamous cell carcinoma of head and neck that has failed to respond to standard therapy, progressed despite standard therapy, for which standard therapy does not offer the potential for increased survival of a least 3 months, or for which no other higher priority therapies are available. Curative therapiestransplantation) are not possible for these patients and new strategies are warranted to enhance immune responsiveness in patients with these indications. Combining a hypoxia-targeted cytotoxic with an anti-CTLA-4 checkpoint inhibitor may lead to enhanced T cell responsiveness to tumor antigens in draining lymph nodes, enhanced T cell penetration into the tumor, and reduction in hypoxia-associated suppressive cell populations, such as myeloid-derived suppressor cells and regulatory T-cells.

The objectives of the study are to determine the recommended Phase 2 dose (RP2D) of combination treatment with evofosfamide and ipilimumab and to determine the preliminary assessment of antitumor efficacy of the combination in prostate cancer, pancreatic cancer, melanoma and HPV negative squamous cell cancer of head and neck. Important exploratory objectives will be to evaluate baseline and change from baseline in post-treatment peripheral blood and tumor tissue immune and hypoxia parameters as potential biomarkers of activity for the ipilimumab-evofosfamide combination therapy.

The study will be conducted at MDACC and will recruit approximately 12-24 patients in the dose escalation phase and up to 45 patients across the four disease-specific dose expansion cohorts. We expect enrollment in this trial to begin early in the second quarter of 2017.

Evofosfamide Programs with Antiangiogenics

Antiangiogenics are a class of anticancer therapies that target the tumor vasculature. A goal of antiangiogenic therapy is to “starve” tumors by disrupting the blood vessel network supplying tumors with oxygen and nutrients needed for survival and growth. While antiangiogenics have proven to be an important new class of targeted cancer therapy, essentially all tumors eventually become resistant to these treatments. Emerging preclinical research suggests that antiangiogenics may also induce tumor hypoxia. Co-targeting tumor angiogenesis and tumor hypoxia, which is believed to be a key driver of treatment resistance, is one approach to potentially prevent or reverse this mechanism of treatment resistance. As evofosfamide is designed to be selectively activated under conditions of severe tumor hypoxia, the combination of evofosfamide with antiangiogenic therapy has the potential to be an effective anticancer treatment. Preclinical models demonstrated enhanced antitumor activity of evofosfamide when used in combination with antiangiogenic therapies (sunitinib and sorafenib), which was directly related to the amount of hypoxia induced by different doses of these antiangiogenics.

Based on preclinical studies, evofosfamide has been or is under investigation in combination with antiangiogenic therapies in a variety of tumor types in human clinical trials including:

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TH-CR-410 Phase 1 dose escalation trial of evofosfamide and sunitinib in patients with RCC, GIST, and pNET

The 410 trial was designed to evaluate standard full dose sunitinib (50 mg) administered daily (Days 1 – 28 of a 6-week cycle) with evofosfamide (240 mg/m² to 480 mg/m²) administered on days 8, 15 and 22. In 2013, preliminary data from the 410 trial were published online in the ASCO 2013 Annual Meeting Proceedings, and updated preliminary results from 12 patients were reported at the 2013 AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics. As reported at AACR-NCI-EORTC, no dose-limiting toxicities were observed in the 4 patients treated in the initial cohort at 240 mg/ m². One of 6 evaluable patients treated at 340 mg/m² had a dose-limiting toxicity of Grade 3 stomatitis. Grade 3 thrombocytopenia and neutropenia were reported in 3 (25%) and 4 (33%) patients, respectively; Grade 4 neutropenia was reported in one patient (8%). Fatigue, nausea, and vomiting were the most common nonhematologic adverse events occurring in 83%, 75%, and 67% of patients, respectively. All cases were Grade 1 or 2 except for one report of Grade 3 nausea. Partial responses were achieved by one of four (25%) evaluable GIST patients (confirmed) and three of eight (37.5%) evaluable RCC patients (one confirmed). All four patients with partial responses had received prior sunitinib.

Enrollment in this trial has been completed, and all patients have discontinued from the trial. The recommended Phase 2 dose of evofosfamide (340 mg/ m²) was established and is being evaluated further in an Investigator Sponsored Trial of evofosfamide in combination with sunitinib in patients with pancreatic neuroendocrine tumors (pNET) (see below).

EMR 200592-012: A Phase 2 trial of evofosfamide in combination with sunitinib in patients with pNET

The -012 trial is an Investigator-Sponsored Phase 2 trial designed to assess the activity and safety of evofosfamide in combination with sunitinib in patients with well- and moderately-differentiated metastatic pancreatic neuroendocrine tumors (pNET) who are naïve to systemic treatment. The study is being sponsored by the Spanish Task Force in Neuroendocrine Tumors.

Enrollment in this Investigator Sponsored Trial commenced in 2015 and it is currently is ongoing. After completion of the study, we will assess whether further development of evofosfamide in combination with sunitinib in patients with pNET is warranted.

TH-IST-4003: Phase 1/2 trial of evofosfamide and bevacizumab in patients with glioblastoma (GBM) following bevacizumab failure

The 4003 trial is a U.S. investigator-sponsored Phase 1/2 clinical trial evaluating evofosfamide in combination with Avastin^® (bevacizumab) in patients with recurrent glioblastoma (GBM) following bevacizumab failure. Surgical resection followed by concomitant radiotherapy and chemotherapy is the standard of care for patients with newly-diagnosed GBM. Single-agent bevacizumab is the only FDA-approved therapy for GBM patients with progressive disease following prior therapy. After disease progression on bevacizumab, patients may start a subsequent bevacizumab-containing regimen.

Preliminary results from the 4003 trial were reported at the ESMO 2012 Congress, the 2013 Scientific Meeting and Education Day of the Society for Neuro-Oncology, or SNO, and most recently at SNO in November 2014. As reported by Andrew J. Brenner, M.D., Ph.D., the study principal investigator at SNO 2014, a total of 23 patients in the Phase 1/2 study were treated with bevacizumab 10 mg/kg every two weeks and evofosfamide dose escalated 240 – 670 mg/m² every two weeks (four-week cycle) until disease progression. Patients had received a median of three prior systemic anticancer regimens including both chemoradiation and bevacizumab. No Grade 4 adverse events were observed. Three Grade 3 adverse events in three patients were observed: skin ulceration at 340 mg/m², thrombocytopenia at 670 mg/m², and oral mucositis at 670 mg/m². Primary evofosfamide-related toxicities were mucosal, but were not dose-limiting: rectal mucositis in one of four (1/4) patients at 480 mg/m² and all patients (13/13) at 670 mg/m² (all Grade 1 or 2). Oral mucositis was less frequent. Best tumor responses in 22 patients evaluable by Response Assessment in Neuro-Oncology (RANO) criteria included one complete response and three partial responses for a response rate of 18%, and ten stable disease assessments for a clinical benefit rate of 64%; eight patients had progressive disease. Median progression-free survival was 2.8 months (95% CI: 1.9 to 3.9 months) and 4-month progression-free survival was 22% (95% CI: 3.2% to 41%). Median overall survival was 4.6 months (95% CI: 3.4 to 6.2 months).

Enrollment has been completed in this investigator-sponsored trial, and the recommended Phase 2 dose of evofosfamide was established at 670 mg/ m² in combination with 10 mg/kg bevacizumab administered every other week. In 2014, the investigator received funding from the FDA to conduct a multiple-center Phase 2 trial of evofosfamide at the recommended Phase 2 dose in combination with bevacizumab in this patient population, as described below. After completion of the study, we will assess whether

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further development of evofosfamide and bevacizumab in patients with glioblastoma (GBM) following bevacizumab failure is warranted.

TH-IST-4008: FDA-funded Phase 2 Investigator Sponsored Trial in GBM

In September 2014, the FDA, through its Office of Orphan Product Development, awarded Dr. Brenner a grant for a Phase 2 clinical trial of evofosfamide for the treatment of GBM, which we refer to as TH-IST-4008. Dr. Brenner's investigator-sponsored Phase 2 trial, which is designed to assess safety and efficacy of 670 mg/m² evofosfamide in combination with bevacizumab for the treatment of recurrent GBM following prior bevacizumab failure, is expected to enroll up to 33 patients. PET imaging will also be conducted in an effort to predict which patients may benefit from evofosfamide combination therapy. Dana Farber Cancer Institute and The University of Texas at Austin are participating in the trial.

Enrollment in this Investigator Sponsored Trial commenced in 2015 and is ongoing.  After completion of the study, we will assess whether further development of evofosfamide in patients with GBM is warranted.

TH-IST-4001: Phase 1 dose escalation trial of evofosfamide and pazopanib in patients with advanced solid tumors

The 4001 trial evaluated evofosfamide in combination with pazopanib in patients with advanced solid tumors. Results were reported at the 2013 AACR-NCI-EORTC annual meeting for the 30 patients enrolled with a variety of solid tumors for whom standard therapy or palliative measures were nonexistent or no longer effective. The clinical benefit rate was 76% (n=25 evaluable patients) with three patients with partial responses (12%) and 16 patients with stable disease (64%). The partial responses were observed in patients with neuroendocrine cancer, ovarian cancer, and chondrosarcoma. Treatment-related Grade 3 hematological adverse events were reported for neutropenia (7%), thrombocytopenia (7%), and anemia (13%). Treatment-related, Grade ≥ 2 nonhematologic adverse events included vomiting/nausea/diarrhea (7% Grade 3), mucositis (7% Grade 3), hand foot syndrome (all Grade 2), and hypertension (all Grade 2). No Grade 4 adverse events have been reported.

The 4001 Investigator Sponsored Trial has completed enrollment. There are no current plans for further investigation of evofosfamide in combination with pazopanib at this time.  

TH-IST-4004: A Phase 1/2 Investigator Sponsored Trial of evofosfamide in combination with sorafenib in patients with advanced kidney cancer or hepatocellular cancer

Study 4004 is a Phase 1/2 Investigator Sponsored Trial designed to evaluate the safety and efficacy of evofosfamide in combination with sorafenib (Sutent®)) in patients with advanced kidney cancer or liver cancer that cannot be removed by surgery.option. The primary objectives of the multicenter Phase I clinical trial of MT-3724 was to assess the tolerability of MT-3724 and to establish the maximum tolerated dose, or MTD of the drug. The secondary objectives of the Phase I clinical trial were to assess the pharmacokinetic profile of MT-3724 after intravenous dosing as well as to assess any biological and clinical activity. This Phase I clinical trial was not designed to show statistical significance of the study endpoints.

Molecular initially filed an IND application with the U.S. Food and Drug Administration, or FDA, on July 31, 2014, and Molecular received the notification from the FDA that it could proceed with the Phase I trial on August 29, 2014 with the first patient dosed in March of 2015. The Phase I trial was a multi-center, open-label,

multiple-dose Phase I, dose-escalation study of MT-3724 in subjects with relapsed, refractory B-cell NHL or chronic lymphocytic leukemia, or CLL. A total of 21 patients were treated with MT-3724 with doses ranging from 5 to 100 mcg/kg. Patients were dosed 3 times per week over two weeks (6 doses) followed by a two-week hiatus for the first cycle, as mandated by the FDA. Subsequent cycles were dosed over two weeks with a one-week hiatus. Originally, up to five cycles of treatment were allowed per protocol. This was subsequently amended to allow for extended dosing beyond five cycles.

Twenty-one patients were treated with escalating doses of MT-3724 starting at the 5 mcg/kg dose level. Nearly all patients experienced at least one adverse event, with peripheral edema, diarrhea, myalgia, cough, fatigue, constipation, nausea, anemia, stomatitis, pyrexia, dizziness, headache, insomnia, dyspnea, being the more commonly reported adverse events. During the study, there were no treatment-related deaths.

The first two patients treated in the 100 mcg/kg/dose cohort developed signs and symptoms of a systemic inflammatory response (a constellation of adverse events including a grade 2 decrease in serum albumin levels, which together were consistent with capillary leak syndrome) in the first cycle of treatment. Upon thorough evaluation of each case, the Data Monitoring Committee, or DMC, deemed the capillary leak syndrome the DLT and determined that the 100 mcg/kg/dose had exceeded the MTD and the cohort was closed to further enrollment. The symptoms related to the DLT were non-life threatening and resolved upon cessation of dosing MT-3724. Six patients were dosed at a reduced dose level of 75 mcg/kg cohort with no DLTs reported. Upon identifying 75 mcg/kg as the maximum tolerated dose, or MTD, the recommended Phase Ib/II dose was designated to be 75 mcg/kg.

To date, 31 serious adverse events, or SAEs have been reported. Most these events were attributed to exacerbation of a pre-existing condition or disease progression. Both subjects in the 100 mcg/kg/dose cohort were withdrawn in cycle 1 for SAEs which the investigator and DMC assessed as DLTs and determined that the MTD had been exceeded.

Molecular has observed promising signals of single-agent activity with MT-3724. Patients in the Phase I trial were of older age (median age = 67) and heavily pre-treated, with a median of four prior therapies. Those patients with ≤ four prior therapies (n=5) were generally chemo-intolerant patients who could not sustain multiple lines of chemo-based regiments. The majority of patients were of the DLBCL subtype (n=15). Of the 14 evaluable DLBCL patients who received MT-3724, eight patients entered the trial with low levels of serum anti-CD20 antibody while six patients had high levels of anti-CD20 antibody. As reported in Molecular’s presentation to the 2016 American Society of Hematology Annual Meeting, or the 2016 ASH Meeting, patients with high anti-CD20 antibody did not respond to MT-3724, presumably due to target inaccessibility. In the eight DLBCL patients with low anti-CD20 antibody, the observed objective response rate, or ORR, was 25% (2/8) including a partial response, or PR, and a complete metabolic response, or CMR. Molecular observed clinical responses starting at the lowest dose level of 5 mcg/kg as shown in Figure 4. The patient who achieved a CMR was eligible for and received an allogeneic stem cell transplant, or SCT. Three patients had stable disease, or SD, with tumor reductions of 19% (10 mcg/kg), 48% (75 mcg/kg), and 49% (100 mcg/kg), respectively. The patient at 100 mcg/kg with 49% tumor reduction had received only a single dose of MT-3724 at the time of measurement. The remaining three patients had progressive disease, or PD. Notably, three of the eight DLBCL patients received fewer than two cycles of MT-3724 due to early withdrawal from the study (including the two patients at the DLT dose of 100 mcg/kg). Significant ADAs were not observed among DLBCL patients and did not appear to neutralize the efficacy of MT-3724 in patients.

Based on the clinical effect observed among DLBCL patients, Molecular has opened a Phase Ib expansion study to further explore the potential of MT-3724 in DLBCL. Molecular expects to enroll up to forty additional DLBCL patients in this study. A brief update on the first three patients dosed in the MT-3724 Phase Ib expansion was delivered at the World ADC Summit Europe on March 28, 2018. Observations included the following:    

Molecular expects to report additional results from this expansion study in the first half of 2018.

Furthermore, Molecular is planning to develop MT-3724 in earlier lines of therapy in combination with chemotherapy and non-chemotherapy based regiments.  Molecular plans on initiating a Phase IIa study combining MT-3724 with a chemo regiment in transplant-ineligible DLBCL patients in mid-2018.  Additionally, a second Phase IIa study evaluating MT-3724 in combination with Revlimid in DLBCL patients is planned to begin mid-2018.  Additional future studies in earlier lines of therapy may include MT-3724 in combination with chemotherapy-based standards of care for 2^nd- and 3^rd-line DLBCL patients that are ineligible for transplant

Recent Presentations

MT-3724 AACR presentation: In April 2017, Molecular presented preclinical data for Molecular’s MT-3724 lead compound at the AACR annual conference. MT-3724 is an ETB with wild-type SLTA and is not de-immunized. Nevertheless, to date, Molecular has not seen a high level of neutralizing antibodies in patients treated with MT-3724, likely because of the nature of their disease (B-cell malignancy) and their prior therapies (B-cell depleting agents), which leave these patients with compromised immune systems. The MT-3724 presentation at AACR demonstrated the reduction in anti-drug antibodies, or ADAs, seen when MT-3724 was co-administered with sirolimus in both murine and non-human primate, or NHP, models. These data may be useful in guiding clinical development of MT-3724 if significant levels of ADAs are seen in patients treated with MT-3724. Additionally, researchers at MD Anderson Cancer Center presented preclinical data on MT-3724 potency against mantle cell lymphoma samples. Researchers demonstrated a substantial survival advantage in a xenograft model using a patient-derived mantle cell lymphoma.

MT-4019—ETB Targeting CD38

Overview

CD38 is a single-chain type II transmembrane glycoprotein that is expressed by a variety of hematologic cells in an activation- and differentiation-dependent manner. Its cellular functions are involved in the regulation of cell proliferation and survival. CD38 is expressed at high rates on patient myeloma samples, making it an important marker and potential target in the development of targeted biologics.

Daratumumab (trade name Darzalex^®) received FDA approval for the treatment of multiple myeloma in 2015. Daratumumab is a monoclonal antibody that binds CD38 on multiple myeloma cells and induces cell death indirectly. Approval was supported by a Phase II pivotal trial in fourth line myeloma patients and subsequent randomized studies in earlier lines of myeloma therapy.  A careful analysis of this study’s results reveals that CD38 expression persists after patients have progressed on daratumumab and that the myeloma cells of patients who relapsed after daratumumab treatment showed an increase in cell surface receptors (CD55 and CD59) that inhibit daratumumab’s ability to recruit an immune response to the myeloma cells (Nijhof et al., 2016). Persistence of a surface marker that is central to disease strongly suggests that a different modality targeting that surface marker and that is not cross-resistant to antibody therapy may provide substantial clinical benefit in myeloma.

Despite cell specific expression, an ADC, approach to CD38 has not been developed, likely because CD38 does not efficiently internalize, thereby limiting the amount of drug that could be delivered to myeloma cells. Because SLTA can force its own internalization and enzymatically inhibit ribosome function thereby killing the cell, Molecular theorized that the engineering of a potent and specific ETB targeted to CD38 could overcome the lack of internalization seen with CD38.

MT-4019 is Molecular’s ETB that specifically targets CD38. The compound was evaluated in many of the same preclinical assays as daratumumab. Daratumumab is an anti-cancer drug originally developed by Genmab. Based on published daratumumab xenograft data, MT-4019 appears to have more potent direct cell-kill activity and more rapid and pronounced activity when tested in the identical xenograft model. However, the mechanism of action of MT-4019 is wholly different than daratumumab, and Molecular believes that MT-4019 may be active in CD38+ myeloma patients that have failed treatment with an anti-CD38 antibody.

The proposed development plan for MT-4019 is modeled on that of daratumumab. After a robust response rate in its Phase I trial, daratumumab was granted Breakthrough Therapy Designation, and its expanded Phase II trial (N=106) was considered sufficient for registration. If similar efficacy is seen with MT-4019, Molecular believes it may be able to pursue a similar accelerated approval strategy via a Phase II clinical trial.  

Preclinical Data with MT-4019

MT-4019 Structure

MT-4019 utilizes Molecular’s updated scaffold in which the fusion of the scFv to the SLTA has been optimized and in which the SLTA portion of the ETB has been de-immunized. MT-4019 has high affinity for the CD38 receptor and potent and specific cell-kill activity against CD38-expressing cells.

De- immunized SLTA scaffold

The host immune response to bacterial proteins used in the treatment of solid tumors has historically prevented prolonged dosing and limited the utility of immunotoxins as a class of molecules. There has been much greater success with immunotoxins in hematological malignancies, as patients tend to be immunosuppressed due both to the nature of their disease and the drugs used in treatment (Kreitman et al., 2006). Multiple myeloma patients show a decreased immune response to bacterial proteins (Jacobson, et al., 1986), and Molecular has further reduced the likelihood of high levels of neutralizing antibodies by using its proprietary de-immunized SLTA, as shown in Molecular’s MT-4019 presentation at the 2017 AACR Annual Meeting.

MT-4019 Binding Specificity

MT-4019 showed high-affinity binding to recombinant CD38 protein and to the CD38+ myeloma H929 cell line. MT-4019 shows no binding to a non-specific protein.

MT-4019 In Vitro Activity

MT-4019 shows extremely potent and specific cell-kill activity against cells that express CD38. MT-4019 was tested for cell-kill activity on H929 and HDLM-2 cells, two commonly used cell lines that are CD38+ and CD38-, respectively. The IC₅₀ (the concentration at which 50% of cells are killed) for MT-4019 was calculated as 16 picomolar (pM) against H929 cells, but Molecular did not observe any measurable cell-kill with MT-4019 against CD38-HDLM-2 cells. A full summary of cell kill results is presented in Table 1.

Table 1. Summary of Cell-Kill Activity for MT-4019

The potency of MT-4019 compares favorably with the potency reported for daratumumab, but direct comparisons are difficult as daratumumab requires the addition of effector cells for cytotoxicity. In an assay measuring the potency of CDC-mediated cell-kill of daratumumab against Daudi cells, the CD₅₀ was reported to be approximately 800pM (de Weers et al., 2011). compared to 58pM with MT-4019 What is likely to be more important than the improved potency seen with MT-4019, though, is its wholly distinct mechanism of action. In patients who have progressed after CD38 treatment but still retain CD38 expression, the direct mechanism of cell kill seen with MT-4019 may be relevant.

MT-4019 In Vivo Activity: MTD Study

MT-4019 and MT-3724 were tested in CB17 SCID mice to determine the maximum-toleratedmaximal tolerated dose, or MTD, of the drug. Mice were dosed via IP injection with either MT-3724 at 1 or 2mg/kg or MT-4019 at 1, 2, or 4 mg/kg. Dosing was three times weekly for two weeks, and recommended Phase 2cage-side observations and body weight measurements were conducted. The doses of MT-4019 were selected based on experience with MT-3724.

The MTD for MT-4019 was not identified within the dose range tested. No deaths were observed during dosing or the recovery period. Average body weight loss appeared dose-dependent with the highest loss for the combination of sorafenib and evofosfamide; overall response rate in patients with advanced hepatocellular cancer will be assessedMT-4019 occurring in the Phase4 mg/kg arm, but even in this arm mean body weight loss was still no more than 5% of baseline (Figure 6). By comparison, at the 2 portion.  mg/kg dose for MT-3724, mean body weight loss was 10%.

This NCI Cooperative Group Sponsored Trial (The Alliance) completed enrolling patients

MT-4019 In Vivo Activity

Molecular replicated the Daudi cell xenograft model used with daratumumab (de Weers, et al.) with MT-4019 to confirm in vivo activity. Molecular implanted luciferase-expressing Daudi cells (2.5 X 10⁶ Daudi cells as in the Phase 1 portiondaratumumab study) in SCID mice and administered varying doses of MT-4019. Due to the smaller size of the younger mice used in the MT-4019 study (5-6 weeks), compared to the daratumumab study (8-10 weeks), the tumor burden per mass was larger for mice in the MT-4019 study. There was variability in tumor enlargement between the daratumumab and is planningMT-4019 models. As measured by the integrated light intensity, tumors were significantly larger at peak in the MT-4019 model than in the daratumumab model (1.5X10¹¹ photons per second in control animals for MT-4019 vs. up to enroll patients into the Phase 2 portion1.0X10⁷ integrated light intensity in control animals for daratumumab). Because of the trialmuch shorter half-life of MT-4019, six administrations were given over two weeks as opposed to one administration of daratumumab.

By Day 40, a statistically significant difference in 2017.bioluminescence imaging (BLI) was seen between mice treated with the vehicle control and mice treated with MT-4019 (Figure 7A). Tumor imaging clearly shows the difference between the treated and untreated mice by day 22 (Figure 7B).

Figure 7. SCID mice were injected intraveneously with 2.5 X 10⁶ Daudi cells expressing luciferase. After completion1hr, the first dose of the study, we will assess whether further developmentMT-4019 or Vehicle was administered intraperitoneally. In total, six doses of evofosfamideMT-4019 were administered over two weeks on a Monday-Wednesday-Friday schedule. Total BLI was measured. Representative imaging for mice treated with Vehicle or 0.5 mg/Kg of MT-4019 at Day 22 are shown in combination with sorafenib in patients with advanced hepatocellular cancer is warranted.  

In addition to the evofosfamide programs with antiangiogenics mentioned above, there is also one monotherapy trial ongoing:

EMR200592-013:  A Phase II Study of TH-302 Monotherapy As Second-Line Treatment in Advanced Biliary Tract Cancer

Study 013 is a Phase 2 Investigator Sponsored Trial designed to evaluate the safety and efficacy of evofosfamide in patients with advanced biliary tract cancer who have failed first-line chemotherapy.  This study is being conducted at Seoul National University Hospital in South Korea.  After completion of the study, we will assess whether further development of evofosfamide in patients with advanced biliary tract cancer is warranted.

[18F]-HX4 Investigational PET Imaging Agent for Hypoxia

Our other product candidate, [18F]-HX4 [flortanidazole (18F)] is an investigational Positron Emission Tomography (PET) imaging agent for hypoxia developed by Siemens Healthcare Molecular Imaging to potentially identify and quantify the degree of hypoxia in tumors in vivo. In view of the results of both Phase 3 trials of evofosfamide and both Phase 2 trials of tarloxotinib as described above, no further clinical development is planned.

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Our Preclinical Candidate

TH-3424 Investigational AKR1C3-Activated Prodrug

TH-3424 is our small-molecule drug candidate, discovered at  Threshold, being evaluated for the potential treatment of hepatocellular (liver) cancer, castrate resistant prostate cancer, T-cell acute lymphoblastic leukemias, and other cancers expressing high levels of aldo-keto reductase family 1 member C3, or AKR1C3. Tumors overexpressing AKR1C3 can be resistant to radiation therapy and chemotherapy. TH-3424 is a prodrug in preclinical development that selectively releases a potent DNA cross-linking agent in the presence of AKR1C3.  Preliminary nonclinical studies including biochemical, in vitro cell-based and in vivo animal-based characterization of its pharmacological properties were presented at the 2016 Annual Meeting of the American Association for Cancer Research (AACR) in April 2016.  The preliminary nonclinical toxicology studies suggested an adequate therapeutic index.  We believe that the preliminary nonclinical study results warranted continued development of TH-3424 in Investigational New Drug (IND)-enabling toxicology studies in collaboration with Ascenta Pharmaceuticals, Ltd. which we expect will be completed by the fourth quarter of 2017. Our evaluation of TH-3424 is at an early stage and our ability to advance evofosfamide if the Merger does not close will require us to obtain significant additional funding, whether through new collaborative, partnering or other strategic arrangements or otherwise with TH-3424.

Market Opportunities

Many different approaches are used in treating cancer, including surgery, radiation and drugs or a combination of these approaches. Drugs used to treat cancer include chemotherapeutics, hormones and immune-based therapies. Traditionally, strategies for designing cancer therapies have focused on killing cancer cells that exhibit rapid division and growth. Such cells are found in regions of the tumor that have an adequate blood supply and therefore receive nutrients and oxygen essential for cell division and growth. However, the vasculature supporting tumors is highly disorganized and irregular. This results in regions of the tumor that do not receive adequate amounts of nutrients and oxygen. Low oxygen concentration within a tumor is called “tumor hypoxia”. Traditional anticancer agents fail to address tumor hypoxia.

Many traditional anticancer agents are not able to penetrate into the hypoxic zones of tumors. Furthermore, cells that reside within regions of tumor hypoxia are relatively quiescent in contrast to highly proliferative cells that are the hallmark of cancer. As many traditional cancer therapies work by blocking cell division, they are not effective in killing the non-dividing, quiescent cells within hypoxic zones. It has also been demonstrated that cells subjected to prolonged hypoxia accumulate changes in their growth properties and genetic mutations that can lead to drug resistance, enhanced metastatic potential, and, ultimately, treatment failure.

Another disadvantage of current cancer therapies that target rapidly dividing cells is their toxic side effects. Because rapidly dividing cells are also found in many healthy tissues, particularly the gastrointestinal tract, bone marrow and hair follicles, nearly all conventional chemotherapy drugs cause severe side effects which may lead to bleeding, infection and anemia, as well as other side effects, such as diarrhea and hair loss. Likewise, radiation generally cannot be administered without causing significant damage to healthy tissue surrounding a tumor.

Given its role in tumor progression, metastasis, resistance, and ultimately treatment failure, hypoxia is emerging as a significant, high-priority target for cancer therapy. As our prodrugs are designed to undergo selective activation under conditions of tumor hypoxia, we anticipate that they should have a favorable safety profile and produce less toxicity to normal tissues at the doses that are effective in treating tumors than is the case with traditional therapies.

We have generated clinical data with evofosfamide alone and administered in combination with multiple anticancer drugs and in multiple cancer types. Drugs that we have tested in combination with evofosfamide include chemotherapies (e.g., doxorubicin, gemcitabine, docetaxel, pemetrexed, bortezomib) and antiangiogenics (e.g., pazopanib, bevacizumab, sorafenib, and sunitinib). The current total market addressed by these drugs exceeds $10 billion. We have tested evofosfamide in numerous indications including pancreatic cancer, glioblastoma, kidney cancer, liver cancer, and gastrointestinal stromal tumors. In the U.S. alone, new cases of these cancers exceed 170,000 per annum.

The table below depicts the latest estimates from the American Cancer Society on expected 2017 incidence and deaths for cancers in the United States that we consider therapeutic areas of interest for evofosfamide.Figure 7B.

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The treatment landscape for pancreatic cancer is described below.MT-4019 Combination Activity

Pancreatic Cancer

It is estimated that 337,872 cases of pancreatic cancer are diagnosed worldwide every year, accounting for 2.4% of all cancers.MT-4019 was combined Almost 67% of cases are diagnosed in people aged 65vitro with pomalidomide, an immunomodulatory imide drug, or IMiD, and over; it is uncommon in people under the age of 45. Pancreatic cancer has a low survival rate regardless of stage of disease, with 93% of patients dying from their disease within 5 years.It is estimated that there are 330,372 deaths from pancreatic cancer worldwide each year.

Gemcitabine is the currentapproved standard of care for patientsrefractory multiple myeloma. H929 cells were pre-treated for either 24 or 72 hours with pancreatic cancerpomalidomide and then treated with MT-4019. An isobologram was calculated to determine whether there was a synergistic effect between the two agents. Strong synergy was demonstrated (Figure 8) which is associatedlikely due to both the differences in mechanism of action between the agents as well as the target for MT-4019 as pomalidomide has been shown to increase the expression of CD38 (Boxhammer, et al., 2015). The differences in mechanism of cell-kill and the effect of pomalidomide on CD38 expression may make the combination of these agents worth exploring in the clinic.

Clinical and Regulatory Plan

Molecular has begun to pursue GMP manufacturing for MT-4019. Molecular has substantial expertise with a median overall survivalthe GMP manufacture of approximately 6 months and an overall response rate of approximately 8%. Two other therapeutic agents have been approved for the first-line treatment of patients with pancreatic cancer. Erlotinib is approved for the first line of treatment of patients with pancreatic cancerETBs based on its registrationalsuccessful production of MT-3724. Molecular has a non-GMP facility in-house and has conducted seven GMP campaigns with MT-3724. From its experience with MT-3724, Molecular believes it can transfer expression of MT-4019 and complete manufacturing for GLP toxicity studies within six months. Based on expression and process improvements, MT-4019 is expected to have similar or better yields than MT-3724.

Molecular initiated IND-enabling studies to fully characterize MT-4019 based on toxicology and pharmacology in 2017. Molecular expect to initiate a Phase 3I clinical trial for MT-4019 in 2018. The Phase I trial will be conducted as a single-arm, open-label, multi-center, dose escalation study in combination with gemcitabine shown to convey a median overall survival of 6.4 months and overall response rate (complete plus partial response rate) of 8.6%. Nab-paclitaxel was approved by the FDA as first–line treatment for patients with metastatic adenocarcinoma of the pancreas, in combination with gemcitabine. ApprovalCD38+ relapsed/refractory multiple myeloma. Molecular was based on an 861-patient Phase 3 clinical trial in chemotherapy-naïve patients with metastatic pancreatic cancer. Nab-paclitaxel plus gemcitabine demonstratedawarded a statistically significant improvement in median overall survival compared to gemcitabine alone (8.5 vs. 6.7 months) (HR 0.72, p<0.0001).

Glufosfamide

From 2004 through 2009 we conducted clinical development of glufosfamide, a drug candidate that shares certain structural characteristics with glucose but acts instead as a chemotherapeutic agent when taken up by a cell. In October 2009, we entered into an exclusive license agreement with Eleison Pharmaceuticals, Inc. or Eleison. Pursuant to the agreement we granted Eleison exclusive worldwide rights to manufacture, develop and commercialize glufosfamide for the treatment of cancer in humans and animals, and certain other uses. Under the agreement, Eleison is responsible$15.2 million grant from CPRIT for the development manufacturingof MT-4019. Molecular expects this grant to cover the cost of IND-enabling studies and marketingthe Phase I and Phase II trials for MT-4019.

Recent Presentations

MT-4019 AACR presentation. Molecular presented data on MT-4019, Molecular’s ETB targeting CD38 utilizing Molecular’s proprietary de-immunized SLTA, at the AACR Meeting in April 2017. The CD38 receptor has been shown to persist in patients after they stop responding to daratumumab, which is a monoclonal antibody that targets CD38 and then engages the patient’s immune system. Monoclonal antibodies attach themselves to multiple myeloma cells and directly kill them and/or signal to the immune system to destroy them. CD38 is a poorly internalizing receptor, rendering it unsuitable for targeting with standard ADCs. Unlike chemotherapy, ADCs are intended to target and kill only the cancer cells and spare healthy cells. ADCs are complex molecules composed of glufosfamide. Under the agreement, amended in January 2016, Eleison will pay Threshold 30%an antibody linked to a biologically active cytotoxic (anticancer) payload or drug. Molecular believes CD38 is an

excellent target for Molecular’s ETB technology. After a robust screening process, Molecular identified MT-4019 as its lead ETB to CD38. MT-4019 utilizes Molecular’s second-generation ETB scaffold and, as presented at AACR, Molecular demonstrated MT-4019’s potent cell-kill activity against CD38-expressing tumor cells with 50% inhibitory concentrations (IC₅₀) achieved at picomolar concentrations of the profitsdrug. MT-4019 also demonstrated reduced innate and adaptive immunity in murine and NHP models vs. MT-3724, an ETB with a wild-type SLTA. Molecular believes this level of commercializationdecreased immunogenicity has not been previously reported for an immunotoxin. Molecular anticipates moving MT-4019 into clinical trials in 2018.

ETB Pipeline

Molecular has launched additional programs against the key targets HER2 and certain sales-based milestone payments, ifPD-L1. Molecular selected HER2 as a target because of its validated role in breast cancer. Targeting HER2 with different modalities (antibody, small molecule and ADC) has shown clinical benefit, and the furthertarget is known to persist after a given modality has failed. The clinical developmentresults seen with Kadcyla (an ADC to HER2) strongly suggests that a direct cell-kill approach to HER2 can provide significant benefit and be well tolerated in patients. Molecular believes that attacking HER2-expressing tumor cells with a differentiated mechanism of glufosfamide leadsdestruction may provide meaningful clinical benefits, even in patients whose disease has progressed on other HER2-targeted modalities. Molecular’s lead HER2 ETB, MT-5111, has shown potent picomolar activity in Kadcyla insensitive HER2+ cell lines and has shown additive or synergistic benefit with Kadcyla in vitro in HER2+ cell lines.

PD-L1 is a focal point for immuno-oncology checkpoint antibodies; its expression on tumors is known to regulatory approvaldownregulate CD8 T-cell activity against tumor cells. In Molecular’s ETB program targeting the PD-L1 receptor, Molecular has focused on targeting PD-L1 with a direct cell-kill approach rather than using it to induce an immune response. In addition, Molecular has integrated its Antigen Seeding Technology to the PD-L1 targeting ETB in order to induce targeted tumors to express CMV antigen in context with MHC-I on the tumor cell surface thereby redirecting an endogenous CMV-specific T-cell response to the tumor.  Molecular believes that targeting PD-L1 expressing tumors via this dual mechanism of ribosome-inactivation and marketing. We have no further development plans for glufosfamide.redirected immunity via CMV-specific T-cell response represents a novel mechanism of action against PD-L1 expressing tumors.  

ETB Research & Development Partnerships

Takeda Pharmaceuticals

In October 2013, Eleison announced that it had initiated a pivotal Phase 3 clinical trial of glufosfamide for the second-line treatment of patients with pancreatic cancer. According to their corporate news release, this pivotal trial will enroll patients with relapsed or refractory pancreatic cancer following prior chemotherapy treatment. The randomized, open-label trial is being conducted to evaluate the safety and efficacy of glufosfamide, with a target enrollment of 480 patients. The primary endpoint is overall survival with a number of pre-specified secondary endpoints. The trial will exclude insulin-treated diabetic patients. Eleison has an agreement with the FDA on an SPA for this Phase 3 clinical trial. The trial is expected to be complete enrollment in 2017.

Discovery Research

As part of the workforce reduction enacted in December 2015, we eliminated our discovery research activities conducted in-house but are exploring further evaluation of our oncology compound discovery program with third-parties.

Manufacturing and Supply

We do not have our own manufacturing capability for the active pharmaceutical ingredient, or API, or the final drug product of evofosfamide. Under our Termination Agreement with Merck KGaA, Threshold has exclusive rights to manufacture evofosfamide for clinical and commercial use.  To date, however, we have relied on, and we expect to continue to rely on, a limited number of third-party single source contract manufacturers and excipient suppliers for the evofosfamide API and evofosfamide drug product to meet our clinical supply needs of evofosfamide. We have no long-term commitments or commercial supply agreements with any of our evofosfamide suppliers. We will need to enter into additional agreements for additional supplies of each of our product candidates to complete clinical development and/or commercialize them. These products will need to satisfy all cGMP manufacturing requirements, including passing product specifications. Our inability to satisfy these requirements could delay our clinical programs.

We base our estimates for the amount of drug product we will need on assumptions about trial enrollment and trial dose levels. If we are not successful in having sufficient quantities of evofosfamide API and drug product manufactured, or if manufacturing is interrupted at our contract manufacturers for evofosfamide API and evofosfamide drug product due to regulatory or other reasons, or consume more drug product than anticipated because of a higher than expected trial utilization or have quality issues that limit the utilization of the drug product, we may experience a significant delay in our evofosfamide clinical program. In any event, additional agreements for more supplies of each of our product candidates, including evofosfamide, will be needed to complete clinical

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development and/or commercialize them. In this regard, we may need to enter into agreements for additional supplies of evofosfamide to commercialize it or develop such capability itself. These products will need to satisfy all cGMP manufacturing requirements, including passing product specifications. Our inability to satisfy these requirements could delay our clinical programs. If evofosfamide is approved by the FDA or other regulatory agencies for commercial sale, we will need to have it manufactured in commercial quantities. It may not be possible to successfully manufacture commercial quantities of evofosfamide and tarloxotinib or increase the manufacturing capacity for evofosfamide or tarloxotinib in a timely or economically feasible manner.

We also expect to rely on contract manufacturers or other third parties to produce sufficient quantities of clinical trial product for any other product candidates that we may develop. It is possible that we might not be able to develop a formulation with adequate quality that meets the need for testing in our clinical trials. In any event, in order for us to commence any planned or potential future clinical trials of our product candidates, we need to obtain or have manufactured sufficient quantities of clinical trial product and there can be no assurance that we will be able to obtain sufficient quantities of clinical trial product in a timely manner or at all.

Research and Development Expenses

During the years ended December 31, 2016, 2015 and 2014, we spent $16.6 million, $40.3 million and $35.8 million, respectively, on research and development, including product development, discovery research and contract manufacturing activities.

License and Development Agreements

Agreement with Merck KGaA

On February 3, 2012, weMolecular entered into a global licensecollaboration and co-developmentoption agreement with Millennium Pharmaceuticals, Inc., a wholly owned subsidiary of Takeda Pharmaceutical Company Ltd., or Takeda, to discover and develop CD38-targeting ETBs, which includes MT-4019 for evofosfamide with Merck KGaA, or the License Agreement.evaluation by Takeda. Under the terms of the agreement, Molecular is responsible for providing to Takeda (i) new ETBs generated using Takeda’s proprietary fully human antibodies targeting CD38 and (ii) MT-4019 for in vitro and in vivo pharmacological and anti-tumor efficacy evaluations. Molecular granted Takeda an exclusive option to negotiate an exclusive worldwide license agreement to develop and commercialize any ETB that may result from this collaboration, including MT-4019. Molecular is entitled to receive up to $2.0 million in technology access fees and cost reimbursement associated with Molecular’s performance and completion of Molecular’s obligations under the agreement. To date, Molecular has received $2.0 million under this agreement.

In June 2017, Molecular entered into a Multi-Target Collaboration and License Agreement Merck KGaAwith Takeda, or the Multi-Target Takeda Agreement, in which Molecular will collaborate with Takeda to identify, generate and evaluate engineered toxin bodies, or ETBs, against certain targets designated by Takeda. Takeda will designate up to two targets of interest as the focus of the research. Takeda will provide to Molecular targeting moieties against the designated targets. Molecular will create and characterize ETBs against those targets and provide them to Takeda for further evaluation. Each party grants to the other nonexclusive rights in its intellectual property for purposes of the conduct of the research, and Molecular agrees to work exclusively with Takeda with respect to the designated targets. To date, Molecular has received co-development rights, exclusive global commercialization rights and provided us$1.0 million under this agreement.  In December 2017, Takeda designated the two targets for development of ETBs under the research collaboration.

Under the agreement, Takeda has an option to co-commercialize evofosfamideacquire an exclusive license under Molecular’s intellectual property to develop, manufacture, commercialize and otherwise exploit ETBs against the designated targets. Upon

exercise of the option, Takeda is obliged to use commercially reasonable efforts to develop and obtain regulatory approval of any licensed ETBs in major market countries, and thereafter to commercialize licensed ETBs in those countries. Molecular is obligated to manufacture ETBs to support research and clinical development through Phase I clinical trials, provided that Takeda can assume manufacturing responsibility at any time.

Molecular received an upfront fee of $1.0 million shortly after execution of the United States,agreement and we wereexpects to receive $4.0 million in April 2018 as upfront fees for approval of program plans for the two designated targets. Molecular may receive net milestone payments of $25.0 million in aggregate through the exercise of the option to license ETBs. Post option exercise, Molecular is entitled to receive an upfront andup to approximately $547.0 million in additional milestone payments through preclinical and clinical development and commercialization. Molecular is also entitled to tiered royalties on commercialroyalty payments of a mid-single to low-double digit percentage of net sales of evofosfamide. To date, we have received upfront and milestone paymentsany licensed ETBs, subject to certain reductions.

The agreement will expire at the end of $110 million. Under the License Agreement, Merck KGaA also paid 70%option period for the designated targets if Takeda does not exercise its options, or, following exercise of worldwidethe option, on the later of the expiration of patent rights claiming the licensed ETB or ten years from first commercial sale of a licensed ETB. The agreement may be terminated sooner by Takeda for convenience or upon a Molecular change of control, or by either party for an uncured material breach of the agreement.

Other Research & Development Collaborations

Henry M. Jackson Foundation

In July 2014, Molecular entered into a non-exclusive license agreement with the Henry M. Jackson Foundation for certain biological materials for use in conjunction with the development costs for evofosfamide.  On March 10, 2016, we and Merck KGaA agreed to terminate the License Agreement pursuant to a termination agreement, or the Termination Agreement.of Molecular’s lead clinical stage ETB MT-3724. Under the terms of the Termination Agreement,agreement, Molecular is required to pay the Henry M. Jackson Foundation aggregate payments totaling $110,000 with respect to this license, upon completion of certain clinical milestones.

Manufacturing

Molecular relies on third-party contract manufacturing organizations, or CMOs, to manufacture and supply Molecular with GMP drug substance and drug product materials to support Molecular’s clinical trials. . The manufacturing processes for MT-3724, MT-4019 and other preclinical ETB candidates have been developed by Molecular’s manufacturing staff. Once a process is developed and defined for an ETB, it is transferred to CMOs to scale-up and optimize for manufacturing that conforms to current GMP, or cGMP, standards. Molecular is building a GMP manufacturing facility located in Austin, TX to supply future clinical trial materials for internal and partnered ETB programs.

Molecular has established well-defined, cost efficient manufacturing under GMP, including bioanalytical, quality control and quality assurance, logistics, distribution and supply chain management. After manufacturing, Molecular’s ETB candidates are tested and released by Molecular’s analytical and quality systems staff in conjunction with some select contract research organizations, or CROs. The quality control organization performs a series of release assays designed to ensure that the product meets all rights underapplicable specifications. Molecular’s quality assurance staff also reviews manufacturing and quality control records prior to batch release in an effort to assure conformance with cGMP as mandated by the License Agreement were returnedFDA and foreign regulatory agencies.

Molecular’s manufacturing staff is trained and routinely evaluated for conformance to Threshold,rigorous manufacturing procedures and quality standards. This oversight is intended to ensure compliance with FDA and foreign regulations and to provide consistent ETB output. Molecular’s quality control and quality assurance staff is similarly trained and evaluated as part of Molecular’s effort to ensure consistency in the testing and release of the product, as well as allconsistency in materials, equipment and facilities.

For the purposes of internal research and support for Molecular’s ongoing collaborations, Molecular has small scale manufacturing capabilities that are sufficient to manufacture drug materials for preclinical research.

Intellectual Property Portfolio

Molecular seeks to protect proprietary rights to Merck KGaA technology developed underits platform technologies through a combination of patents and patent applications, trade secrets and know-how. Molecular’s platform technologies include ETBs directed to specific molecular targets, in which a Shiga toxin A subunit construct is linked to an immunoglobulin domains directed to the License Agreement.  Undertarget, and their uses for treating cancer, killing cancer cells and selectively delivering payload molecules into a target cell. Molecular’s platform technologies also include various ETB scaffolds regardless of target, and the termsShiga toxin components of ETBs, including improved Shiga toxin A subunit constructs having disruptions of B-cell epitopes and/or T-cell epitopes for reduced immunogenicity when used in ETB scaffolds.

To cover its proprietary technologies and its current pipeline of proprietary ETB products and related methods, such as methods of use, Molecular has filed patent applications representing 13 international patent families, together covering 102 pending regional and national applications worldwide, including 15 pending U.S. patent applications and 87 foreign patent applications currently pending in the regional European Patent Office and nine other jurisdictions outside of the Termination Agreement, Merck KGaA is entitled to tiered royalties on net sales of evofosfamide, if any,U.S. and milestone payments contingent upon the future successful development and commercialization of evofosfamide. To date, we have received upfront and milestone payments of $110 million.  We previously recorded these as deferred revenue and amortized them over the estimated performance period.  

As a result of the termination of the License Agreement, we are no longer eligible to receive any further milestone payments or other funding from Merck KGaA, including the 70% of worldwide development costs for evofosfamide that were previously borne by Merck KGaA under the License Agreement. Since we are now solely responsible for the further development and commercialization of evofosfamide at our own cost, we are evaluating potential partnering opportunities for evofosfamide, and in this regard, we are currently seeking a pharmaceutical partner for evofosfamide with a commercial presence in oncology in Japan.  In any event, our ability to advance the clinical development of evofosfamide is dependent upon our ability to enter into new collaborative or partnering arrangements for evofosfamide, or to otherwise obtain sufficient additional funding for such development.  

Threshold will be responsible for the commercialization of evofosfamide.  Threshold is evaluating further development and commercialization opportunities for evofosfamide with other partners.

Agreement with Auckland Uniservices Ltd

On September 23, 2014, we entered into an exclusive license agreement with Auckland UniServices Ltd., a wholly-owned company of the University of Auckland.  Pursuant to the agreement, we licensed exclusive worldwide rights to a development program based on tarloxotinib from the University of Auckland. Under the terms of this agreement, we made no upfront payment but we are required to pay all costs of development, as well as possible annual license maintenance fees starting in September 2017.

Agreement with Ascenta Pharmaceuticals, Inc.

On February 1, 2016, we entered into a patent assignment and development agreement with Ascenta Pharmaceuticals, Inc. Pursuant to the agreement, we granted Ascenta exclusive rights inEurope (Australia, Canada, China, Hong Kong, Macao and Taiwan to manufacture, develop and commercialize TH-3424 for the treatment of cancer in humans and animals, and certain other uses. Under the agreement, Ascenta is responsible for pre-IND activities for the development of TH-3424 and if an IND Application is filed in one of these countries Ascenta’s rights can be expanded to includeIsrael, India, Japan, South Korea Singapore, Malaysia, Thailand, Turkey and India.  Ascenta would beMexico).

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responsibleMolecular’s patent families covering ETBs and modified ETB scaffolds for the development, manufacture and commercializationtargeted killing of TH-3424cancer cells or for the selective delivery of molecules into a target cell include 12 internationally filed patent families. Patent rights in those countries and Thresholdthese patent families, if granted, will expire without extension in 2034-2038. Molecular also has rights to development, manufacture and commercialization in the rest of the world.

Under the agreement, Ascenta will pay us 30% ofa patent prosecution costs before they are assigned.  If an initial new drug (IND) application is accepted in the U.S, Threshold will reimburse 50% of approved development expenses incurred associated with filing the IND. The agreement will remain in effect as long as Ascenta continues to develop TH-3424 in its territory. Each party is entitled to terminate the agreement upon the other party’s material breach after expiration of a 60-day cure period (30 days in the event of a payment breach). The parties are entitled to mutually terminate the agreement. In addition, Ascenta may terminate the agreement upon change of control of Threshold or 60 days prior to receipt of marketing approval from the CFDA for TH-3424. Following any termination, all assigned rights will revert to us.

Agreement with Eleison Pharmaceuticals, Inc.

On January 8, 2016, we amended the exclusive license agreement with Eleison. Pursuantfamily directed to the original agreement effective on October, 18, 2009, wescreening of large ETB libraries, in which patent rights, if granted, Eleison exclusive worldwidewill expire without extension in 2035. With respect to its ETB pipeline, Molecular’s lead compound which targets CD20, MT-3724, and pharmaceutical compositions and uses of MT-3724, are covered by two international patent families. Patent rights to manufacture, developin these patent families, if granted, will expire without extension in 2034 and commercialize glufosfamide for the treatment of cancer2036. Molecular’s current pipeline also includes ETBs which target CD38, HER2, and PD-L1, covered by numerous patent applications, including one international patent family from which patent rights, if granted, will expire without extension in humans and animals, and certain other uses. Under the agreement, Eleison is responsible for the development, manufacturing and marketing of glufosfamide.2036.

Under the amendment, Eleison will pay us 30% of its profits from commercialization on a quarterly basis, beginning on the date of first commercial sale, if any. Eleison has the right to sublicense some or all of its rights under the agreement, and will pay us 30% of amounts received under any sublicenses, including, without limitation, any royalty payments, license fee payments, milestone payments and payments for any equity or debt purchases by a sublicensee, within 30 days of the receipt of any such amounts or payments by Eleison. In addition, Eleison is now required to pay us up to $175 million in potential sales-based milestone payments. Eleison will bear all costs associated with development, commercialization and patent prosecution, and will control product development and commercialization. In addition, Eleison will be responsible for all royalty and milestone payments due under certain agreements pursuant to which we licensed rights related to glufosfamide. The agreement contemplates that Eleison, to satisfy its diligence obligations, will raise sufficient funds to continue clinical development activities with glufosfamide. In the event that Eleison fails to satisfy its diligence obligations, we may, at our option, terminate the agreement for material breach or convert the license granted under the agreement to a non-exclusive license.

The agreement will remain in effect as long as Eleison continues to sell glufosfamide anywhere in the world or receives payments under any sublicenses. Each party is entitled to terminate the agreement upon the other party’s material breach after expiration of a 60-day cure period (30 days in the event of a payment breach). Each party is entitled to terminate the agreement immediately upon the bankruptcy or similar petition of the other party that is not discharged within 60 days, or the assignment for the benefit of creditors by, or the appointment of a receiver over the property of, the other party. In addition, Eleison may terminate the agreement for convenience at any time on 90 days written notice to us.

Following any termination by Eleison for convenience or by us for Eleison’s material breach, all licensed rights will revert to us. Following any termination by Eleison for our material breach, all licensed rights will fully vest in Eleison, provided that Eleison will be required to pay us 30% of the profit sharing payments it otherwise would have been required to pay us under the agreement.

Patents and Proprietary Rights

Our policy is to patent the technologies, inventions and improvements that we consider important to the development of our business. As of March 27,December 31, 2017, weMolecular owned 123132 U.S. and foreign patents and patent applications relating to evofosfamidehypoxia-activated prodrugs and itstheir manufacture, formulation and use.use, including covering the investigational prodrug evofosfamide currently in clinical development. These include 913 issued U.S. patents expiring from 2024 to 20362031 and 7698 issued foreign patents expiring from 2024 to 2032(in2036 (in each case, without including any regulatory-delay based patent term extension), as well as 114 pending U.S., 31 pending Patent Cooperation Treaty and 2416 pending foreign national patent applications, which, if issued, would in each case expire from 2024 to 2037 (without including any regulatory- or patent office-delay based patent term extension).

Although we have U.S. and foreign issued patents that cover certain hypoxia-targeted prodrugs, including evofosfamide and tarloxotinib, we have no issued patents or pending patent applications that would prevent others from taking advantage of hypoxia-targeted prodrug technology generally to discover and develop new therapies for cancer or other diseases. Consequently, our competitors may seek to discover and develop potential therapeutics that operate by mechanisms of action that are the same or similar to the mechanisms of action of our hypoxia-targeted prodrug product candidates.Government Regulation

The patent positions of companies like ours are generally uncertain and involve complex legal and factual questions. Our ability to maintain and solidify our proprietary position for our technology will depend on our success in obtaining effective claims and enforcing those claims once granted. We do not know whether any of our pending patent applications will result in the issuance of any

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patents. Moreover, an issued patent does not guarantee us the right to practice the patented technology or commercialize the patented product. Other parties may have blocking patents that could be used to prevent us from commercializing our patented products and practicing our patented technology. Our issued patents and those that may be issued in the future may be challenged, invalidated, or circumvented, which could limit our ability or render us unable to stop competitors from marketing related products as well as shorten the term of patent protection that we may have for our products. In addition, the rights granted under any issued patents may not provide us with proprietary protection or competitive advantages against competitors with similar technology. Furthermore, our competitors may independently develop similar technologies that do not infringe our intellectual property rights. For these reasons, we may have competition for our products. Moreover, because of the extensive time required for development, testing and regulatory review of a potential therapeutic product, it is possible that, before any of our products can be commercialized, any related patent may expire or remain in force for only a short period following commercialization, thereby reducing any advantage of the patent. If we are not able to obtain adequate protection for, or defend, the intellectual property position of evofosfamide, tarloxotinib or any other potential future product candidates, then we may not be able to retain or attract collaborators to partner our development programs. Further, even if we can obtain protection for and defend the intellectual property position of evofosfamide, tarloxotinib or any potential future product candidates, we or any of our potential future collaborators still may not be able to exclude competitors from developing or marketing competing drugs. Should this occur, we and potential future collaborators may not generate any revenues or profits from evofosfamide, tarloxotinib or any potential future product candidates or our revenue or profit potential would be significantly diminished.

We also rely on trade secrets, technical know-how and continuing innovation to develop and maintain our competitive position. We seek to protect our proprietary information by requiring our employees and certain of our consultants, contractors, outside scientific collaborators and other advisors to execute non-disclosure and assignment of invention agreements on commencement of their employment or engagement. Agreements with our employees also forbid them from using third party trade secret or other confidential information in their work. We also require confidentiality or material transfer agreements from third parties that receive our confidential data or proprietary materials.

The biotechnology and pharmaceutical industries are characterized by the existence of a large number of patents and frequent litigation based on allegations of patent infringement. For so long as our product candidates are in clinical trials, we believe our clinical activities fall within the scope of the exemptions provided by 35 U.S.C. Section 271(e)Government authorities in the United States which exempts from patent infringement liability activities reasonably related toat the federal, state and local level and in other countries regulate, among other things, the research, development, testing, manufacture, quality control, approval, labeling, packaging, storage, record-keeping, promotion, advertising, distribution, post-approval monitoring and submissionreporting, marketing and export and import of information to the FDA. This exemption does not apply to commercialization activities; however, if ourdrug and biological products, such as MT-3724, MT-4019, and any future product candidates are commercialized, then the possibility ofcandidates. Generally, before a patent infringement claim against us increases. While we attempt to ensure that our clinical product candidates and the methods we employ to manufacture them, as well as the methods for their use we intend to promote, do not infringe other parties’ patents and other proprietary rights, therenew drug or biologic can be no assurance that they do not,marketed, considerable data demonstrating its quality, safety and competitors or other parties may assert that we infringe their proprietary rights in any event.efficacy must be obtained, organized into a format specific for each regulatory authority, submitted for review and approved by the regulatory authority.

CompetitionU.S. Drug Development

We operate inIn the highly competitive segment of the pharmaceutical market comprised of pharmaceutical and biotechnology companies that research, develop and commercialize products designed to treat cancer. Many of our competitors have significantly greater financial, manufacturing, marketing, research and product development resources than we do. Large pharmaceutical companies in particular have extensive experience in clinical testing and in obtaining regulatory approval for drugs. These companies also have significantly greater research capabilities than we do. In addition, many universities and private and public research institutes are active in cancer research, some in direct competition with us. We also compete with these organizations to recruit scientists and clinical development personnel.

Each cancer indication for which we are or may be developing products has a number of established medical therapies with which our candidates will compete. Most major pharmaceutical companies and many biotechnology companies are aggressively pursuing cancer development programs, including traditional therapies and therapies with novel mechanisms of action. Our evofosfamide and tarloxotinib product candidates for targeting the tumor hypoxia are likely to be in highly competitive markets and may eventually compete with other therapies offered by companies who are developing or were developing drugs that target tumor hypoxia. Our competitors may succeed in developing their products before we do, obtaining approvals fromUnited States, the FDA regulates drugs under the Federal Food, Drug, and Cosmetic Act, or other regulatory agencies forFDCA, and its implementing regulations and biologics under the FDCA, the Public Health Service Act, or PHSA, and their products more rapidly than we do, or developing products that are more effective than evofosfamide. These products or technologies might render our technology obsolete or noncompetitive. There mayimplementing regulations. Both drugs and biologics also be product candidates of which we are not aware at an earlier stage of development that may compete with evofosfamide.

Our cancer product candidates face competition from established biotechnology and pharmaceutical companies and from generic pharmaceutical manufacturers. In particular, if approved for commercial sale for pancreatic cancer, evofosfamide would compete with Gemzar^®, marketed by Eli Lilly and Company; Tarceva^®, marketed by Roche/Genentech and Astellas Oncology; Abraxane^® marketed by Celgene; and FOLFIRINOX, which is a combination of generic products that are sold individually by many manufacturers.

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Governmental Regulation and Product Approval

The manufacturing and marketing of our potential products and our ongoing research and development activities are subject to extensive regulationother federal, state and local statutes and regulations. The process of obtaining regulatory approvals and the subsequent compliance with applicable federal, state, local and foreign statutes and regulations requires the expenditure of substantial time and financial resources. Failure to comply with the applicable U.S. requirements at any time during the product development process, approval process or post-market may subject an applicant to administrative or judicial sanctions. These sanctions could include, among other actions, the FDA’s refusal to approve pending applications, withdrawal of an approval, a clinical hold, untitled or warning letters, product recalls or market withdrawals, product seizures, total or partial suspension of production or distribution, injunctions, fines, refusals of government contracts, restitution,

disgorgement and civil or criminal penalties. Any agency or judicial enforcement action could have a material adverse effect on Molecular. MT-3724, MT-4019 and any ETB product candidates must be approved by the FDA and comparable regulatory agencies in state and local jurisdictions and in foreign countries.

United States Regulation

Before any of our products canthrough either a New Drug Application, or NDA, or Biologics Licensing Application, BLA, process before they may be legally marketed in the United States, they must secure approval by the FDA. To secure this approval, any drug we develop must undergo rigorous preclinical testing and clinical trials that demonstrate the product candidate’s safety and effectiveness for each chosen indication for use. This extensive regulatoryStates. The process controls, among other things, the development, testing, manufacture, safety, efficacy, record keeping, labeling, storage, approval, import, export, advertising, promotion, sale, and distribution of biopharmaceutical products.

In general, the process required by the FDA before investigational drugs may be marketed in the United Statesgenerally involves the following steps:following:

The preclinical testing, clinical trials and the approval process requires substantial time, effort and financial resources, and Molecular cannot be certain that any approvals for MT-3724, MT-4019 and any future product candidates will be granted on a timely basis, or at all. The data required to support an NDA or BLA are generated in two distinct developmental stages: preclinical and clinical. The preclinical developmental stage generally involves laboratory evaluations of drug chemistry, formulation and stability, as well as studies to evaluate toxicity in animals, which support subsequent clinical testing. The sponsor must submit the results of the preclinical studies, together with manufacturing information, analytical data, any available clinical data or literature and a proposed clinical protocol, to the FDA as part of the IND. An IND is a request for authorization from the FDA to administer an investigational new drug applicationto humans and must become effective before human clinical trials may begin.

The clinical stage of development involves the administration of the investigational product to healthy volunteers or NDA,patients under the supervision of qualified investigators, generally physicians not employed by or under the trial sponsor’s control, in accordance with GCP requirements, which include the requirement that all research subjects provide their informed consent for their participation in any clinical trial. Clinical trials are conducted under protocols detailing, among other things, the objectives of the clinical trial, dosing procedures, subject selection and exclusion criteria and the parameters to be used to monitor subject safety and assess efficacy. Each protocol, and any subsequent amendments to the protocol, must be submitted to the FDA as part of the IND. Furthermore, each clinical trial must be reviewed and approved by an IRB at each institution at which the clinical trial will be conducted to ensure that the risks to individuals participating in the clinical trials are minimized and are reasonable in relation to anticipated benefits. The IRB also approves the informed consent form that must be provided to each clinical trial subject or his or her legal representative and must monitor the clinical trial until completed. There also are requirements governing the reporting of ongoing clinical trials and completed clinical trial results to public registries.

A sponsor who wishes to conduct a clinical trial outside of the United States may, but need not, obtain FDA authorization to conduct the clinical trial under an IND. If a foreign clinical trial is not conducted under an IND, the

sponsor may submit data from the clinical trial to the FDA in support of an NDA supplement (for subsequent indications).or BLA. The FDA will accept a well-designed and well-conducted foreign clinical trial not conducted under an IND if the trial was conducted in accordance with GCP requirements, and the FDA is able to validate the data through an onsite inspection if deemed necessary.

Preclinical TestingStudies and IND

In the United States, drug candidates are testedPreclinical studies include laboratory evaluation of product chemistry and formulation, as well as in animals until adequate proof of safety is established. These preclinicalvitro and animal studies generally evaluate the mechanism of action of the product, expose andto assess the potential safetyfor adverse events and efficacyin some cases to establish a rationale for therapeutic use. The conduct of the product. Tested compoundspreclinical studies is subject to federal regulations and requirements, including GLP regulations. An IND sponsor must be produced according to applicable current good manufacturing practice, or cGMP, requirements and preclinical safety tests must be conducted in compliance with FDA and international regulations regarding good laboratory practices, or GLP. Thesubmit the results of the preclinical tests, together with manufacturing information, and analytical data, are generally submittedany available clinical data or literature and plans for clinical trials, among other things, to the FDA as part of an IND. Some long-term preclinical testing, such as animal tests of effects on reproduction and carcinogenicity, may continue after the IND which must be become effective before human clinical trials may commence. Theis submitted. An IND will automatically becomebecomes effective 30 days after receipt by the FDA, unless before that time, the FDA requests an extension or raises concerns aboutor questions and places the conduct ofIND on clinical hold. In such a case, the clinical trials as outlined in the application. If the FDA has any concerns, theIND sponsor of the application and the FDA must resolve theany outstanding concerns before the hold is lifted and before clinical trialstrial can begin. SubmissionAs a result, submission of an IND may not result in the FDA authorization to commence a clinical trial. A separate submission to the existing IND must be made for each successive clinical trial conducted during product development. Investigator Sponsored Trials are INDs held by investigators that utilize investigational drugs supplied by a pharmaceutical manufacturer.  Data generated under Investigator Sponsored Trials may not be as robust as commercially sponsored IND trials. Regulatory authorities may require additional data before allowing the clinical trials to commence or proceed from one Phase to another, and could demand that the trials be discontinued or suspended at any time if there are significant safety issues. Furthermore, an independent institutional review board, or IRB, for each medical center proposing to participate in the conduct of the clinical trial must review and approve the clinical protocol and patient informed consent before the center commences the clinical trial. [18F]-HX4 [flortanidazole (18F)] will require submission of a separate IND.commence.

Clinical Trialstrials

Clinical trials for new drug candidatesgenerally are typically conducted in three sequential phases, under Good Clinical Practices, thatknown as Phase I, Phase II and Phase III, which may overlap.

Post-approval trials, sometimes referred to as Phase 3IV clinical trials, may be conducted after initial marketing approval. These trials are used to gain additional experience from the basistreatment of patients in the intended therapeutic indication. In certain instances, the FDA may mandate the performance of Phase IV clinical trials as a condition of approval of an NDA or BLA.

Progress reports detailing the results of the clinical trials, among other information, must be submitted at least annually to the FDA and written IND safety reports must be submitted to the FDA and the investigators for determining ifserious and unexpected suspected adverse events, findings from other studies suggesting a significant risk to humans exposed to the drug, should be approvedfindings from animal or in vitro testing that suggest a significant risk for commercialization. During allhuman subjects and any clinically important increase in the rate of a serious suspected adverse reaction over that listed in the protocol or investigator brochure.

Phase I, Phase II and Phase III clinical trials physicians monitor patients to determine effectiveness of the drug candidate and observe and reportmay not be completed successfully within any adverse effects or safety risks that may result from use of the drug candidate.specified period, if at all. The FDA the IRB, or the sponsor may

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suspend or terminate a clinical trial at any time on various grounds, including a finding that the research subjects or patients are being exposed to an unacceptable health riskrisk. Similarly, an IRB can suspend or thatterminate approval of a clinical trial at its institution if the clinical trial is not being conducted in accordance with the IRB’s requirements or if the drug is not sufficiently efficacious or biologic has been associated with unexpected serious harm

to continue further studies.

Thepatients. Additionally, some clinical trials are overseen by an independent group of qualified experts organized by the clinical trial sponsor, known as a data safety monitoring board or committee. This group provides authorization for whether a trial may move forward at designated check points based on access to certain data from the trial. Concurrent with clinical trials, togethercompanies may perform additional animal studies and develop additional information about the chemistry and physical characteristics of the drug or biologic as well as finalize a process for manufacturing the product in commercial quantities in accordance with cGMP requirements. Additionally, appropriate packaging must be selected and tested and stability studies must be conducted to demonstrate that MT-3724, MT-4019 and any future product candidates do not undergo unacceptable deterioration over their shelf life.

NDA/BLA and FDA Review Process

Following completion of the clinical trials, data are analyzed to assess whether the investigational product is safe and effective for the proposed indicated use or uses. The results of preclinical datastudies and other supporting information that establishes a drug candidate’s safety profile and efficacy,clinical trials are then submitted to the FDA in the formas part of an NDA or BLA, along with proposed labeling, chemistry and manufacturing information to ensure product quality and other relevant data. In short, the NDA supplement (foror BLA is a request for approval to market the drug or biologic for one or more specified indications and must contain proof of safety and efficacy for a drug or safety, purity and potency for a biologic. Data may come from company-sponsored clinical trials intended to test the safety and efficacy of a product’s use or from a number of alternative sources, including studies initiated by investigators. To support marketing approval, the data submitted must be sufficient in quality and quantity to establish the safety and efficacy of the investigational product to the satisfaction of FDA. FDA approval of an NDA or BLA must be obtained before a new indication ifdrug or biologic may be marketed in the United States.

Under the Prescription Drug User Fee Act, or PDUFA, as amended, each NDA or BLA must be accompanied by a user fee. FDA adjusts the PDUFA user fees on an annual basis. According to the FDA’s fee schedule, for fiscal year 2017, the user fee for an application requiring clinical data, such as an NDA or BLA, is $2,038,100. PDUFA also imposes an annual product fee for human drugs and biologics (approximately $97,750) and an annual establishment fee (approximately $0.51 million) on facilities used to manufacture prescription drugs and biologics. Fee waivers or reductions are available in certain circumstances, including a waiver of the application fee for the first application filed by a small business. Additionally, no user fees are assessed on NDAs or BLAs for products designated as orphan drugs, unless the product candidate is already approvedalso includes a non-orphan indication.

The FDA reviews all submitted NDAs and BLAs before it accepts them for another indication).filing, or it may refuse to file the application and request additional information. The cost of preparing and submittingFDA must make a decision on accepting an NDA is substantial. Under federal law, the submission of most NDAs is additionally subject to a substantial application user fee, and the manufacturer and/or sponsor under an approved NDA are also subject to annual product and establishment user fees. Under applicable laws and FDA regulations, each NDA submitted for FDA assessment is reviewedBLA for filing within 60 days followingof receipt. Once the submission is accepted for filing, the FDA begins an in-depth review of the NDA. If deemed acceptable,NDA or BLA. Under the goals and policies agreed to by the FDA under PDUFA, the FDA has 10 months, from the filing date, in which to complete its initial review of a new molecular-entity (NME) or nonNME NDA or original BLA and respond to the applicant, and six months from the filing date of a NME NDA or original BLA designated for priority review. The FDA does not always meet its PDUFA goal dates for standard and priority NDAs or BLAs, and the review process is often extended by FDA requests for additional information or clarification.

Before approving an NDA or BLA, the FDA will “file”conduct a pre-approval inspection of the NDA, thereby initiatingmanufacturing facilities for the new product to determine whether they comply with cGMP requirements. The FDA will not approve the product unless it determines that the manufacturing processes and facilities are in compliance with cGMP requirements and adequate to assure consistent production of the product within required specifications. The FDA also may audit data from clinical trials to ensure compliance with GCP requirements. Additionally, the FDA may refer applications for novel drug products or drug products which present difficult questions of safety or efficacy to an advisory committee, typically a panel that includes clinicians and other experts, for review, evaluation and a recommendation as to whether the application should be approved and under what conditions, if any. The FDA is not bound by recommendations of an advisory committee, but it considers such recommendations when making decisions on approval. The FDA likely will reanalyze the clinical trial data, which could result in extensive discussions between the FDA and the applicant during the review clock triggering substantive reviewprocess. After the FDA evaluates an NDA or BLA, it will issue an approval letter or a Complete Response Letter. An approval letter authorizes commercial marketing of the application. The FDA can refuse to file any NDAdrug with specific prescribing information for specific indications. A Complete Response Letter indicates that it deems incomplete or not properly reviewable. The FDA has established internal goals of reviewing and acting on NDAs within six months of filing for priority NDAs (for drugs addressing serious or life threatening conditions for which there is an unmet medical need) and ten months of filing for standard NDAs. Prioritythe review is assigned by the FDA to drugs that it determines offer major advances in treatment, or provide a treatment where no adequate therapy exists. The FDA, however, is not legally required to complete its review within these periods, and these performance goals may change over time. Following a complete reviewcycle of the application is complete and the FDAapplication will either issue an approval or a complete response letter outliningnot be approved in its present form. A Complete Response Letter usually describes all of the specific deficiencies in the submission, which may require substantial additional testing or information for the FDA to reconsider the application. The FDA’s review of an NDA may involve review and recommendations by an independent FDA advisory committee. The FDA may deny approval of an NDA or NDA supplement ifBLA identified

by the applicable regulatory criteria are not satisfied, or itFDA. The Complete Response Letter may require additional clinical data, and/or anincluding additional pivotal Phase 3III clinical trial. Risk Evaluationtrial(s) and/or other significant and Mitigation Strategies,time-consuming requirements related to clinical trials, preclinical studies or REMS,manufacturing. If a Complete Response Letter is issued, the applicant may be required for approvaleither resubmit the NDA or BLA, addressing all of an NDA.the deficiencies identified in the letter, or withdraw the application. Even if such data or REMSand information are submitted, the FDA may ultimately decide that the NDA or NDA supplementBLA does not satisfy the criteria for approval.

Data Review and Approval

Satisfaction of FDA requirements or similar requirements of state, local and foreign regulatory agencies typically takes several years and requires the expenditure of substantial financial resources. Information generated in this process is susceptible to varying interpretations that could delay, limit, or prevent regulatory approval at any stage of the process. Accordingly, the actual time and expense required to bring a product to market may vary substantially. We cannot be certain that we will submit applications for required authorizations to manufacture and/or market potential products or that any such application will be reviewed and approved by the appropriate regulatory authorities in a timely manner, if at all. Data obtained from clinical activities istrials are not always conclusive and may be susceptible to varying interpretations that could delay, limit, or prevent regulatory approval. Success in early stage clinical trials does not ensure success in later stage clinical trials. Even if a product candidate receives regulatory approval, the approval may be significantly limited to specific disease states, patient populations, and dosages, or have conditions placed on them that restrict the commercial applications, advertising, promotion, or distribution of these products.

Once issued, the FDA may withdraw product approval if ongoing regulatory standards are not met or if safety problems occur afterinterpret data differently than Molecular interpret the product reaches the market. In addition, the FDA may require testing and surveillance programs to monitor the effect of approved products that have been commercialized, and the FDA has the power to prevent or limit further marketing of a product based on the results of these post-marketing programs. The FDA may also request additional clinical trials after a product is approved. These so-called postmarketing, or Phase 4 studies, may be made a condition to be satisfied after a drug receives approval. The results of postmarketing studies can confirm the effectiveness of a product candidate and can provide important safety information to augment the FDA’s voluntary adverse drug reaction reporting system. The product may be subject to withdrawal of the approval if effectiveness is not confirmed in the Phase 4 studies. Any products manufactured or distributed by us pursuant to FDA approvals would be subject to continuing regulation by the FDA, including record-keeping requirements and reporting of adverse experiences with the drug. Drug manufacturers and their subcontractors are required to register their establishments with the FDA and certain state agencies, and are subject to periodic unannounced inspections by the FDA and certain state agencies for compliance with good manufacturing practices, which impose certain procedural and documentation requirements upon us and our third-party manufacturers. We cannot be certain that we or our present or future suppliers will be able to comply with the cGMP regulations and other FDA regulatory requirements. If our present or future suppliers are not able to comply with these requirements, the FDA may halt our clinical trials, require us to recall a drug from distribution, or withdraw approval of the NDA for that drug. Furthermore, even after regulatory approval is obtained, later discovery of previously unknown problems with a product may result in restrictions on the product or even complete withdrawal of the product from the market.

The FDA closely regulates the marketing and promotion of drugs. Approval may be subject to post-marketing surveillance and other record keeping and reporting obligations, and involve ongoing requirements. Product approvals may be withdrawn if compliance with regulatory standards is not maintained or if problems occur following initial marketing. A company can make only those claims relating to safety and efficacy that are approved by the FDA and is specifically included in drug labeling. While physicians may prescribe legally available drugs for uses that are not described in the product’s labeling and that differ from those tested by us and approved by the FDA, manufacturers may only promote for the approved indications and in accordance with the provisions of the

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approved label. Failure to comply with FDA requirements can result in adverse publicity, warning letters, corrective advertising, and potential civil and criminal penalties.

Special Protocol Assessments

A clinical trial sponsor may submit a request for an SPA from the FDA. Under the SPA procedure, a sponsor may seek the FDA’s agreement on the design and size of a clinical trial intended to form the primary basis of an effectiveness claim. If the FDA agrees in writing, its agreement may not be changed after the trial begins, except in limited circumstances, such as when a substantial scientific issue essential to determining the safety and effectiveness of a product candidate is identified after a Phase 3 clinical trial is commenced and agreement is obtained with the FDA. If the outcome of the trial is successful, the sponsor will ordinarily be able to rely on it as the primary basis for approval with respect to effectiveness. The FDA, however, may make an approval decision based on a number of factors, including the degree of clinical benefit, and the FDA is not obligated to approve an NDA as a result of an SPA, even if the clinical outcome is positive.same data.

Orphan Drug Designation

Under the Orphan Drug Act, the FDA may grant orphan drug designation to drugsa drug or biological product intended to treat a rare disease or condition, which is generally a disease or condition that affects fewer than 200,000 individuals in the United States.States, or more than 200,000 individuals in the United States for which there is no reasonable expectation that the cost of developing and making the product available in the United States for this type of disease or condition will be recovered from sales of the product. Orphan drug designation must be requested before submitting an NDA.NDA or BLA. After the FDA grants orphan drug designation, the identity of the therapeutic agent and its potential orphan use are disclosed publicly by the FDA. Orphan drug designation does not convey any advantage in or shorten the duration of the regulatory review and approval process.

If a product that has orphan drug designation subsequently receives the first FDA approval for the disease or condition for which it has such designation, the product is entitled to orphan productdrug exclusivity, which means that the FDA may not approve any other applications to market the same drug for the same disease,indication for seven years from the date of such approval, except in limited circumstances, for seven years. These circumstances are an inabilitysuch as a showing of clinical superiority to supply the drug in sufficient quantities or a situation in which a new formulationproduct with orphan exclusivity by means of the drug has shown superiorgreater effectiveness, greater safety or efficacy orproviding a major contribution to patient care. This exclusivity,care or in instances of drug supply issues. Competitors, however, also could block themay receive approval of oureither a different product for seven yearsthe same indication or the same product for a different indication but that could be used off-label in the orphan indication.

Expedited Development and Review Programs

The FDA has a fast track program that is intended to expedite or facilitate the process for reviewing new drugs and biologics that meet certain criteria. Specifically, new drugs and biologics are eligible for fast track designation if they are intended to treat a competitor obtainsserious or life threatening condition and preclinical or clinical data demonstrate the potential to address unmet medical needs for the condition. Fast track designation applies to both the product and the specific indication for which it is being studied. The sponsor can request the FDA to designate the product for fast track status any time before receiving NDA or BLA approval, but ideally no later than the pre-NDA or pre-BLA meeting.

Any product submitted to the FDA for marketing, including under a fast track program, may be eligible for other types of FDA programs intended to expedite development and review, such as priority review and accelerated approval. Any product is eligible for priority review if it treats a serious or life-threatening condition and, if approved, would provide a significant improvement in safety and effectiveness compared to available therapies.

The FDA will attempt to direct additional resources to the evaluation of an application for a new drug or biologic designated for priority review in an effort to facilitate the review. A product may also be eligible for accelerated approval, if it treats a serious or life-threatening condition and generally provides a meaningful advantage over available therapies. In addition, it must demonstrate an effect on a surrogate endpoint that is reasonably likely to predict clinical benefit or on a clinical endpoint that can be measured earlier than irreversible morbidity or mortality, or IMM, that is reasonably likely to predict an effect on IMM or other clinical benefit. As a condition of approval, the FDA may require that a sponsor of a drug or biologic receiving accelerated approval perform adequate and well-controlled post-marketing clinical trials. If the FDA concludes that a drug or biologic shown to be effective can be safely used only if distribution or use is restricted, it will require such post-marketing restrictions, as it deems necessary to assure safe use of the product.

Additionally, a drug or biologic may be eligible for designation as a breakthrough therapy if the product is intended, alone or in combination with one or more other drugs or biologics, to treat a serious or life-threatening

condition and preliminary clinical evidence indicates that the product may demonstrate substantial improvement over currently approved therapies on one or more clinically significant endpoints. The benefits of breakthrough therapy designation include the same benefits as fast track designation, plus intensive guidance from the FDA to ensure an efficient drug development program. Fast track designation, priority review, accelerated approval and breakthrough therapy designation do not change the standards for approval, but may expedite the development or approval process.

Pediatric Information

Under the Pediatric Research Equity Act, or PREA, an NDA or BLA or supplement to a NDA or BLA must contain data to assess the safety and efficacy of the drug for the same indication.claimed indications in all relevant pediatric subpopulations and to support dosing and administration for each pediatric subpopulation for which the product is safe and effective. The FDA may grant deferrals for submission of pediatric data or full or partial waivers. The Food and Drug Administration Safety and Innovation Act, or FDASIA, amended the FDCA to require that a sponsor who is planning to submit a marketing application for a drug that includes a new active ingredient, new indication, new dosage form, new dosing regimen or new route of administration submit an initial Pediatric Study Plan, or PSP, within 60 days of an end-of-Phase II meeting or, if there is no such meeting, as early as practicable before the initiation of the Phase III or Phase II/III study. The initial PSP must include an outline of the pediatric study or studies that the sponsor plans to conduct, including study objectives and design, age groups, relevant endpoints and statistical approach, or a justification for not including such detailed information, and any request for a deferral of pediatric assessments or a full or partial waiver of the requirement to provide data from pediatric studies along with supporting information. The FDA and the sponsor must reach an agreement on the PSP. A sponsor can submit amendments to an agreed-upon initial PSP at any time if changes to the pediatric plan need to be considered based on data collected from preclinical studies, early phase clinical trials and/or other clinical development programs.

Post-marketing Requirements

Following approval of a new product, the manufacturer and the approved product are subject to continuing regulation by the FDA, including, among other things, monitoring and record-keeping activities, reporting of adverse experiences, and complying with promotion and advertising requirements, which include restrictions on promoting approved drugs for unapproved uses or patient populations (known as “off-label use”). Although physicians may prescribe legally available drugs for off-label uses, manufacturers may not market or promote such uses. Prescription drug promotional materials must be submitted to the FDA in conjunction with their first use. Further, if there are any modifications to the drug or biologic, including changes in indications, labeling or manufacturing processes or facilities, the applicant may be required to submit and obtain FDA approval of a new NDA/BLA or NDA/BLA supplement, which may require additional data from preclinical studies or clinical trials.

The FDA may also place other conditions on approvals including the requirement for REMS to assure the safe use of the product. If the FDA concludes a REMS is needed, the sponsor of the NDA or BLA must submit a proposed REMS. The FDA will not approve the NDA or BLA without an approved REMS, if required. A REMS could include medication guides, physician communication plans or elements to assure safe use, such as restricted distribution methods, patient registries and other risk minimization tools. Any of these limitations on approval or marketing could restrict the commercial promotion, distribution, prescription or dispensing of products. Product approvals may be withdrawn for non-compliance with regulatory standards or if problems occur following initial marketing. FDA regulations require that products be manufactured in specific approved facilities and in accordance with cGMPs. Molecular rely, and expect to continue to rely, on third parties for the production of clinical and commercial quantities of Molecular’s products in accordance with cGMPs. These manufacturers must comply with cGMPs that require, among other things, quality control and quality assurance, the maintenance of records and documentation and the obligation to investigate and correct any deviations from cGMP. Manufacturers and other entities involved in the manufacture and distribution of approved drugs or biologics are required to register their establishments with the FDA and certain state agencies, and are subject to periodic unannounced inspections by the FDA and certain state agencies for compliance with cGMP requirements and other laws. Accordingly, manufacturers must continue to expend time, money and effort in the area of production and quality control to maintain cGMP compliance. The discovery of violative conditions, including failure to conform to cGMPs, could result in enforcement actions, and the discovery of problems with a product after approval may result in restrictions on a product, manufacturer or holder of an approved NDA or BLA, including recall.

Companion Diagnostics and Complementary Diagnostics

Molecular believes that the success of Molecular’s product candidates may depend, in part, on the development and commercialization of either a companion diagnostic or complementary diagnostic. Companion diagnostics and complementary diagnostics can identify patients who are most likely to benefit from a particular therapeutic product; identify patients likely to be at increased risk for serious side effects as a result of treatment with a particular therapeutic product; or monitor response to treatment with a particular therapeutic product for the purpose of adjusting treatment to achieve improved safety or effectiveness. Companion diagnostics and complementary diagnostics are regulated as medical devices by the FDA. The level of risk combined with available controls to mitigate risk determines whether a companion diagnostic device requires Premarket Approval Application, or PMA, approval or is cleared through the 510(k) premarket notification process. For a novel therapeutic product for which a companion diagnostic device is essential for the safe and effective use of the product, the companion diagnostic device should be developed and approved or 510(k)-cleared contemporaneously with the therapeutic. The use of the companion diagnostic device will be stipulated in the labeling of the therapeutic product.

Other Health Care LawsRegulatory Matters

In additionManufacturing, sales, promotion and other activities following product approval may also be subject to FDA restrictions,regulation by other federal and state laws restrict our business practices. Inregulatory authorities in the United States we are subjectin addition to various federalthe FDA, Depending on the nature of the product, those authorities may include the CMS, other divisions of the Department of Health and Human Services, the Department of Justice, the Drug Enforcement Administration, the Consumer Product Safety Commission, the Federal Trade Commission, OSHA, the Environmental Protection Agency and state and local governments.

For example, in the United States, sales and marketing must comply with state and federal fraud and abuse laws. These laws pertaining to healthcare, including, without limitation, “fraud and abuse” laws such as anti-kickback and false claims laws, data privacy and security laws, and payment transparency laws.

Theinclude the federal Anti-Kickback LawStatute, which makes it illegal for any person, including a prescription drug manufacturer (or a party acting on its behalf), to among other things, knowingly and willfully solicit, receive, offer receive or pay any remuneration directly or indirectly, in exchange for, orthat is intended to induce the referral of business,or reward referrals, including the purchase, recommendation, order or prescription of a particular drug, for which payment may be made under a federal healthcare programsprogram, such as Medicare andor Medicaid. Violations of thethis law are punishable by up to five years in prison, criminal fines, administrative penalties, civil money penalties and exclusion from participation in federal healthcare programs. Due toIn addition, the breadth of these laws,Patient Protection and the potential for additional legalAffordable Care Act, or regulatory change addressing some of our practices, it is possible that our practices or our relationships with physicians might be challenged under anti-kickback laws, which could harm us.

Civil and Criminal false claims laws and civil monetary penalties laws prohibit,ACA, among other things, any person or entity from knowingly presenting, or causing to be presented, for payment to third-party payors (including Medicare and Medicaid) claims for reimbursed items or services, including drugs, that are false or fraudulent, claims for items or services not provided as claimed, or claims for medically unnecessary items or services. Our future activities relating toamends the reportingintent requirement of wholesaler or estimated retail prices for our products, the reporting of Medicaid rebate information and other information affecting federal, state and third-party reimbursement of our products, and the sale and marketing of our products, are subject to scrutiny under these laws. In addition, pharmaceutical companies have been prosecuted under the federal civil False Claims Act in connection with their off-label promotion of drugs. Penalties for a violation of the civil False Claims Act, some of which may be broader in scope, include three times the actual damages sustainedAnti-Kickback Statute and criminal healthcare fraud statutes created by the government, plus mandatory civil penalties of between $5,500 and $11,000 for each separate false claim. In addition, certain states have enacted laws modeled after the federal civil False Claims Act. If the government were to allege that we were, or convict us of, violating these false claims laws, we could be subject to substantial penalties, including, for example, potentially significant fines which may cause a decline in our stock price.

The federal Health Insurance Portability and Accountability Act of 1996, or HIPAA, created newHIPAA. A person or entity no longer needs to have actual knowledge of the statute or specific intent to violate it. Moreover, the ACA provides that the government may assert that a claim including items or services resulting from a violation of the federal criminal statutes that prohibit among other actions, knowingly and willfully executing, or attempting to execute,Anti-Kickback Statute constitutes a scheme to defraud any healthcare benefit program, including private third-party payors and knowingly and willfully falsifying, concealing or covering up a material fact or making any materially false fictitious or fraudulent statement in connectionclaim for purposes of the False Claims Act.

Pricing and rebate programs must comply with the deliveryMedicaid rebate requirements of the U.S. Omnibus Budget Reconciliation Act of 1990 and more recent requirements in the ACA. If products are made available to authorized users of the Federal Supply Schedule of the General Services Administration, additional laws and requirements apply. Products must meet applicable child-resistant packaging requirements under the U.S. Poison Prevention Packaging Act. Manufacturing, sales, promotion and other activities also are potentially subject to federal and state consumer protection and unfair competition laws.

The distribution of pharmaceutical products is subject to additional requirements and regulations, including extensive record-keeping, licensing, storage and security requirements intended to prevent the unauthorized sale of pharmaceutical products.

The failure to comply with any of these laws or paymentregulatory requirements subjects firms to possible legal or regulatory action. Depending on the circumstances, failure to meet applicable regulatory requirements can result in criminal prosecution, fines or other penalties, injunctions, requests for healthcare benefits, itemsrecall, seizure of products, total or services.  partial suspension of production, denial or withdrawal of product approvals or refusal to allow a firm to enter into supply contracts, including government contracts. Any action against Molecular for violation of these laws, even if Molecular successfully defend against it, could cause Molecular to incur significant legal expenses and divert Molecular’s management’s attention from the operation of Molecular’s business. Prohibitions or restrictions on sales

21or withdrawal of future products marketed by Molecular could materially affect Molecular’s business in an adverse way.

In addition, we may be subjectChanges in regulations, statutes or the interpretation of existing regulations could impact Molecular’s business in the future by requiring, for example: (i) changes to data privacy and security regulation by bothMolecular’s manufacturing arrangements; (ii) additions or modifications to product labeling; (iii) the federal government and the states in which we conduct our business.  HIPAA, as amended by the Health Information Technology for Economic and Clinical Health Act,recall or HITECH, and its implementing regulations, imposes certain requirements relating to the privacy, security and transmissiondiscontinuation of individually identifiable health information

Additionally, the federal Physician Payments Sunshine Act, created under the Patient Protection and Affordable Care Act, as amended by the Health Care Education Reconciliation Act, collectively the ACA, and its implementing regulations, require certain manufacturers of drugs, devices, biological products and medical supplies to report annually information related to certain paymentsMolecular’s products; or other transfers of value provided to physicians and teaching hospitals and to report annually certain ownership and investment interests held by physicians and their immediate family members.  

In addition, many states have adopted laws similar to the aforementioned laws. Some of these state prohibitions may be broader in scope and may apply to referral of patients for healthcare services reimbursed by(iv) additional record-keeping requirements. If any source, not only the Medicare and Medicaid programs. Additionally, our business operations in foreign countries and jurisdictions may subject us to additional regulation.

If our operations are foundsuch changes were to be in violation of any of the health regulatory laws described above or any other laws that apply to us, we may be subject to penalties,  including potentially significant criminal and civil and/or administrative penalties, damages, fines, disgorgement, imprisonment, exclusion from participation in government healthcare programs,  contractual damages, reputational harm, administrative burdens, diminished profits and future earnings,  and the curtailment or restructuring of our operations, any of whichimposed, they could adversely affect our ability to operate our businessthe operation of Molecular’s business.

U.S. Patent-term Restoration and our resultsMarketing Exclusivity

Depending upon the timing, duration and specifics of operations.

Drug Price CompetitionFDA approval of MT-3724, MT-4019 and Patent Term Restoration Actany future product candidates, some of 1984

UnderMolecular’s U.S. patents may be eligible for limited patent term extension under the Drug Price Competition and Patent Term Restoration Act of 1984, knowncommonly referred to as the Hatch-Waxman Amendments, a portion of a product’s patent term that was lost during clinical development and application review by the FDA may be restored.Amendments. The Hatch-Waxman Amendments also provide for a statutory protection, knownpermit restoration of the patent term of up to five years as nonpatent market exclusivity, against the FDA’s acceptance or approval of certain competitor applications. The Hatch-Waxman Amendments also provide the legal basis for the approval of abbreviated new drug applications, or ANDAs, for generic drugs.

Patent term restoration can compensatecompensation for patent lifeterm lost during product development and theFDA regulatory review process by returning up to five yearsprocess. Patent-term restoration, however, cannot extend the remaining term of patent life for a patent that coversbeyond a new product or its use. Thistotal of 14 years from the product’s approval date. The patent-term restoration period is generally one-half the time between the effective date of an IND (falling after issuance of the patent) and the submission date of an NDA or BLA plus the time between the submission date of an NDA or BLA and the approval of that application. Patent term restorations, however, are subjectapplication, except that the review period is reduced by any time during which the applicant failed to a maximumexercise due diligence. Only one patent applicable to an approved drug is eligible for the extension of five years, and the patent term restoration cannot extendapplication for the remaining termextension must be submitted prior to the expiration of a patent beyond a total of 14 years.the patent. The U.S. PTO, in consultation with the FDA, reviews and approves the application for any patent term extension is subjector restoration. In the future, Molecular may apply for restoration of patent term for Molecular’s currently owned or licensed patents to add patent life beyond its current expiration date, depending on the expected length of the clinical trials and other factors involved in the filing of the relevant NDA or BLA.

Market exclusivity provisions under the FDCA also can delay the submission or the approval byof certain applications. The FDCA provides a five-year period of non-patent marketing exclusivity within the United States Patent and Trademark Office in conjunction withto the FDA. It takes at least six monthsfirst applicant to obtaingain approval of the application for patent term extension. Up to five years of interim one year extensions are available if a product is still undergoing development or FDA review at the time of its expiration.

The Hatch-Waxman Amendments also provideNDA for a period of statutory protection for new drugs that receive NDA approval from the FDA. If a newchemical entity. A drug receives NDA approval asis a new chemical entity meaning thatif the FDA has not previously approved any other new drug containing the same active moiety, thenwhich is the Hatch-Waxman Amendments prohibitmolecule or ion responsible for the action of the drug substance. During the exclusivity period, the FDA may not accept for review an abbreviated new drug application, or anANDA, or a 505(b)(2) NDA submitted by another company for another version of such drug where the applicant does not own or have a legal right of reference to all of the data required for approval, or a “505(b)(2)” NDA, toapproval. However, an application may be submitted by another companyafter four years if it contains a certification of patent invalidity or non-infringement. The FDCA also provides three years of marketing exclusivity for a generic version of such drug, with some exceptions, for a period of five years from the date of approval of the NDA. The statutory protection provided pursuantNDA, 505(b)(2) NDA or supplement to the Hatch-Waxman Amendments will not prevent the filing or approval of a full NDA. In order to gain approval of a fullan existing NDA however, a competitor would be required to conduct its own preclinical investigations and clinical trials. If NDA approval is received for a new drug containing an active ingredient that was previously approved by the FDA but the NDA is for a drug that includes an innovation over the previously approved drug, for example, an NDA approval for a new indication or formulation of the drug with the same active ingredient, and if such NDA approval was dependent upon the submission to the FDA of new clinical investigations, other than bioavailability studies, that were conducted or paid forsponsored by the sponsor, then the Hatch-Waxman Amendments prohibitapplicant are deemed by the FDA from making effectiveto be essential to the approval of the application, for example, new indications, dosages or strengths of an ANDA or a 505(b)(2) NDA for a generic versionexisting drug. This three-year exclusivity covers only the conditions of such drug for a period of three years from the date of the NDA approval. This three year exclusivity, however, only covers the innovationuse associated with the NDA to which it attaches. Thus, the three year exclusivitynew clinical investigations and does not prohibit the FDA with limited exceptions, from approving ANDAs or 505(b)(2) NDAs for drugs containing the sameoriginal active ingredient but withoutagent. Five-year and three-year exclusivity will not delay the new innovation.

While the Hatch-Waxman Amendments provide certain patent term restoration and exclusivity protections to innovator drug manufacturers, it also permits the FDA to approve ANDAs for generic versionssubmission or approval of their drugs. The ANDA process permits competitor companies to obtain marketing approval for a drug with the same active ingredient for the same uses but does not require the conduct and submission of clinical trials demonstrating safety and effectiveness for that product. Instead of safety and effectiveness data,full NDA. However, an ANDA applicant needs only to submit data demonstrating that its product is bioequivalent to the innovator product as well as relevant

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chemistry, manufacturing and control data. The Hatch-Waxman Amendments also institutedsubmitting a third type of drug application that requires the same information as anfull NDA including full reports of clinical and preclinical studies except that some of the information from the reportswould be required for marketing approval comes from studies which the applicant does not own or have a legal right of reference. This type of application, a “505(b)(2) NDA,” permits a manufacturer to obtain marketing approval for a drug without needing to conduct or obtain a right of reference forto all of the required studies.preclinical studies and adequate and well-controlled clinical trials necessary to demonstrate safety and effectiveness.

Finally,An abbreviated approval pathway for biological products shown to be similar to, or interchangeable with, an FDA-licensed reference biological product was created by the Hatch-Waxman Amendments require,Biologics Price Competition and Innovation Act of 2009, or BPCIA, as part of the ACA. This amendment to the PHSA, in some circumstances, an ANDA or a 505(b)(2) NDA applicantpart, attempts to notifyminimize duplicative testing. Biosimilarity, which requires that the patent ownerbiological product be highly similar to the reference product notwithstanding minor differences in clinically inactive components and that there be no clinically meaningful differences between the product and the holderreference product in terms of safety, purity and potency, can be shown through analytical studies, animal studies and a clinical trial or trials. Interchangeability requires that a biological product be biosimilar to the reference product and that the product can be expected to produce the same clinical results as the reference product in any given patient and, for products administered multiple times to an individual, that the product and the reference product may be alternated or switched after one has been previously administered without increasing safety risks or risks of diminished efficacy relative to exclusive use of the approved NDAreference biological

product without such alternation or switch. Complexities associated with the larger, and often more complex, structure of biological products as compared to small molecule drugs, as well as the processes by which such products are manufactured, pose significant hurdles to implementation that are still being worked out by the FDA.

A reference biological product is granted 12 years of data exclusivity from the time of first licensure of the factualproduct, and legal basisthe FDA will not accept an application for a biosimilar or interchangeable product based on the reference biological product until four years after the date of first licensure of the applicant’s opinion thatreference product. “First licensure” typically means the patent listedinitial date the particular product at issue was licensed in the United States. Date of first licensure does not include the date of licensure of (and a new period of exclusivity is not available for) a biological product if the licensure is for a supplement for the biological product or for a subsequent application by the holdersame sponsor or manufacturer of the approved NDAbiological product (or licensor, predecessor in FDA’s Orange Book is not validinterest, or will not be infringed (the patent certification process). Upon receipt of this notice,other related entity) for a change (not including a modification to the patent owner and the NDA holder have 45 days to bring a patent infringement suit in federal district court and obtain a 30-month stay against the company seeking to reference the NDA. The NDA holder could still file a patent suit after the 45 days, but if they did, they would not have the benefitstructure of the 30-month stay. Alternatively, after this 45-day period,biological product) that results in a new indication, route of administration, dosing schedule, dosage form, delivery system, delivery device or strength, or for a modification to the applicantstructure of the biological product that does not result in a change in safety, purity, or potency. Whether a subsequent application, if approved, warrants exclusivity as the “first licensure” of a biological product is determined on a case-by-case basis with data submitted by the sponsor.

Pediatric exclusivity is another type of regulatory market exclusivity in the United States. Pediatric exclusivity, if granted, adds six months to existing regulatory exclusivity periods. This six-month exclusivity, which attaches to both the twelve-year and four-year exclusivity periods for reference biologics, may file a declaratory judgment action, seeking a determination that the patent is invalid or will not be infringed. Dependinggranted based on the circumstances, however, the applicantvoluntary completion of a pediatric trial in accordance with an FDA-issued “Written Request” for such a trial. Furthermore, a biological product seeking licensure as biosimilar to or interchangeable with a reference product indicated for a rare disease or condition and granted seven years of orphan drug exclusivity may not be able to demonstrate a controversy sufficient to confer jurisdiction onlicensed by the court. The discovery, trial and appeals process in such suits can take several years. If such a suit is commenced,FDA for the Hatch-Waxman Act provides a 30-month stay onprotected orphan indication until after the approvalexpiration of the competitor’s ANDA or 505(b)(2) NDA. If the litigation is resolved in favor of the competitorseven-year orphan drug exclusivity period or the challenged patent expires during the 30-month period, unless otherwise extended by court order, the stay12-year reference product exclusivity, whichever is lifted and the FDA may approve the application. Under the Modernization Act, the patent owner and the NDA holder have the opportunity to trigger only a single 30-month stay per ANDA or 505(b)(2) NDA.later.

Foreign ApprovalsEuropean Union Drug Development

In additionthe European Union, Molecular’s future products also may be subject to regulationsextensive regulatory requirements. As in the United States, we willdrugs, which are referred to as medicinal products can be marketed only if a marketing authorization from the competent regulatory agencies has been obtained.

Similar to the United States, the various phases of preclinical and clinical research in the European Union are subject to significant regulatory controls. Although the EU Clinical Trials Directive 2001/20/EC has sought to harmonize the EU clinical trials regulatory framework, setting out common rules for the control and authorization of clinical trials in the EU, the EU Member States have transposed and applied the provisions of the Directive differently. This has led to significant variations in the member state regimes. Under the current regime, before a varietyclinical trial can be initiated, a clinical trial application must be approved in each of foreign regulations governingthe EU countries where the trial is to be conducted by two distinct bodies: the National Competent Authority, or NCA, and one or more Ethics Committees, or ECs. Under the current regime all suspected unexpected serious adverse reactions to the investigated drug that occur during the clinical trial have to be reported to the NCA and ECs of the Member State where they occurred. The EU clinical trials legislation currently is undergoing a transition process mainly aimed at harmonizing and streamlining clinical-trial authorization, simplifying adverse-event reporting procedures, improving the supervision of clinical trials and commercial salesincreasing their transparency.

European Union Drug Review and distributionApproval

In the European Economic Area, or EEA, which is comprised of our products. Whetherthe 27 Member States of the European Union (including Norway and excluding Croatia), Iceland and Liechtenstein, medicinal products can only be commercialized after obtaining a Marketing Authorization, or MA. There are two types of marketing authorizations.

Under the above described procedures, before granting the MA, the EMA or the competent authorities of the Member States of the EEA make an assessment of the risk-benefit balance of the product on the basis of scientific criteria concerning its quality, safety and efficacy.

European Union New Chemical Entity Exclusivity

In the European Union, new chemical entities, sometimes referred to as new active substances, qualify for eight years of data exclusivity upon marketing authorization and an additional two years of market exclusivity. The data exclusivity, if granted, prevents regulatory authorities in the European Union from referencing the innovator’s data to assess a generic application for eight years, after which generic marketing authorization can be submitted, and the innovator’s data may be referenced, but not approved for two years. The overall ten-year period will be extended to a maximum of 11 years if, during the first eight years of those 10 years, the marketing authorization holder obtains an authorization for one or more new therapeutic indications which, during the scientific evaluation prior to their authorization, are determined to bring a significant clinical benefit in comparison with currently approved therapies.

European Union Orphan Designation and Exclusivity

In the European Union, the EMA’s Committee for Orphan Medicinal Products grants orphan drug designation to promote the development of products that are intended for the diagnosis, prevention or treatment of life-threatening or chronically debilitating conditions affecting not more than 5 in 10,000 persons in the European Union community (or where it is unlikely that the development of the medicine would generate sufficient return to justify the investment) and for which no satisfactory method of diagnosis, prevention or treatment has been authorized (or, if a method exists, the product would be a significant benefit to those affected).

In the European Union, orphan drug designation entitles a party to financial incentives such as reduction of fees or fee waivers and 10 years of market exclusivity is granted following medicinal product approval. This period may be reduced to six years if the orphan drug designation criteria are no longer met, including where it is shown that the product is sufficiently profitable not to justify maintenance of market exclusivity. Orphan drug designation must be requested before submitting an application for marketing approval. Orphan drug designation does not convey any advantage in, or shorter than that required for FDA approval. Theshorten the duration of, the regulatory review and approval process.

Rest of the World Regulation

For other countries outside of the European Union and the United States, such as countries in Eastern Europe, Latin America or Asia, the requirements governing the conduct of clinical trials, product licensing, pricing and reimbursement vary greatly from country to country. Additionally, the clinical trials must be conducted in accordance with GCP requirements and the applicable regulatory requirements and the ethical principles that have their origin in the Declaration of Helsinki.

Under European UnionIf Molecular fail to comply with applicable foreign regulatory systems, werequirements, Molecular may submit marketing authorizations either underbe subject to, among other things, fines, suspension or withdrawal of regulatory approvals, product recalls, seizure of products, operating restrictions and criminal prosecution.

Reimbursement

Sales of Molecular’s products will depend, in part, on the extent to which Molecular’s products will be covered by third-party payors, such as government health programs, commercial insurance and managed care organizations. In the United States no uniform policy of coverage and reimbursement for drug or biological products exists. Accordingly, decisions regarding the extent of coverage and amount of reimbursement to be provided for any of Molecular’s products will be made on a centralized or decentralized procedure. The centralized procedure providespayor-by-payor basis. As a result, the coverage determination process is often a time-consuming and costly process that will require Molecular to provide scientific and clinical support for the grantuse of Molecular’s products to each payor separately, with no assurance that coverage and adequate reimbursement will be obtained.

The United States government, state legislatures and foreign governments have shown significant interest in implementing cost containment programs to limit the growth of government-paid health care costs, including price-controls, restrictions on reimbursement and requirements for substitution of generic products for branded prescription drugs. For example, the ACA contains provisions that may reduce the profitability of drug products through increased rebates for drugs reimbursed by Medicaid programs, extension of Medicaid rebates to Medicaid managed care plans, mandatory discounts for certain Medicare Part D beneficiaries and annual fees based on pharmaceutical companies’ share of sales to federal health care programs. Adoption of general controls and measures, coupled with the tightening of restrictive policies in jurisdictions with existing controls and measures, could limit payments for pharmaceutical drugs. The Medicaid Drug Rebate Program requires pharmaceutical manufacturers to enter into and have in effect a single marketing authorizationnational rebate agreement with the Secretary of the Department of Health and Human Services as a condition for states to receive federal matching funds for the manufacturer’s outpatient drugs furnished to Medicaid patients. The ACA made several changes to the Medicaid Drug Rebate Program, including increasing pharmaceutical manufacturers’ rebate liability by raising the minimum basic Medicaid rebate on most branded prescription drugs from 15.1% of average manufacturer price, or AMP, to 23.1% of AMP and adding a new rebate calculation for “line extensions” (i.e., new formulations, such as extended release formulations) of solid oral dosage forms of branded products, as well as potentially impacting their rebate liability by modifying the statutory definition of AMP. The ACA also expanded the universe of Medicaid utilization subject to drug rebates by requiring pharmaceutical manufacturers to pay rebates on Medicaid managed care utilization and by enlarging the population potentially eligible for Medicaid drug benefits. Congress and President Trump have expressed their intention to repeal or repeal and replace the ACA. If that is validdone, many if not all of the provisions of the ACA may no longer apply to prescription drugs.

The Medicare Prescription Drug, Improvement, and Modernization Act of 2003, or the MMA, established the Medicare Part D program to provide a voluntary prescription drug benefit to Medicare beneficiaries. Under Part D, Medicare beneficiaries may enroll in prescription drug plans offered by private entities that provide coverage of outpatient prescription drugs. Unlike Medicare Part A and B, Part D coverage is not standardized. While all Medicare drug plans must give at least a standard level of coverage set by Medicare, Part D prescription drug plan sponsors are not required to pay for all European Union member states. The decentralized procedure providescovered Part D drugs, and each drug plan can develop its own drug formulary that identifies which drugs it will cover and at what tier or level. However, Part D prescription drug formularies must include drugs within each therapeutic category and class of covered Part D drugs, though not necessarily all the drugs in each category or class. Any formulary used by a Part D prescription drug plan must be developed and reviewed by a pharmacy and therapeutic committee. Government payment for mutual recognition of national approval decisions. Under this procedure, the holder of a national marketing authorization may submit an application to the remaining member states. Within 90 days of receiving the applications and assessment report, each member state must decide whether to recognize approval.

Under the Japanese regulatory system administered by the Pharmaceuticals and Medical Devices Agency (PMDA), pre-marketing approval and clinical studies are required for all pharmaceutical products. To obtain manufacturing/ marketing approval, we must submit an application for approval to the MHLW with results of nonclinical and clinical studies to show the quality, efficacy and safety of a new drug. A data compliance review, GCP on-site inspection, cGMP audit and detailed data review are undertaken by the PMDA. The application is then discussed by the committeessome of the Pharmaceutical Affairs and Food Sanitation Council (PAFSC). Based on the resultscosts of these reviews, the final decision on approval is madeprescription drugs may increase demand for products for which Molecular receive marketing approval. However,

any negotiated prices for Molecular’s products covered by Ministry of Health, Labour and Welfare (MHLW).  In Japan, the National Health Insurance system maintains a Drug Price List specifying which pharmaceutical products are eligible for reimbursement, and the MHLW setsPart D prescription drug plan likely will be lower than the prices ofMolecular might otherwise obtain. Moreover, while the products on this list. AfterMMA applies only to drug benefits for Medicare beneficiaries, private payors often follow Medicare coverage policy and payment limitations in setting their own payment rates. Any reduction in payment that results from the approval, negotiations regarding the reimbursement price with MHLW will begin. The price will be determined within 60 to 90 days unless the applicant disagrees, whichMMA may result in extendeda similar reduction in payments from non-governmental payors.

For a drug product to receive federal reimbursement under the Medicaid or Medicare Part B programs or to be sold directly to U.S. government agencies, the manufacturer must extend discounts to entities eligible to participate in the 340B drug pricing negotiations.program. The government generally introduces price cut rounds every other yearrequired 340B discount on a given product is calculated based on the AMP and also mandates price decreases for specific products. New products judged innovative or useful, that are indicated for pediatric use, or that target orphan or small population diseases, however, mayMedicaid rebate amounts reported by the manufacturer. As of 2010, the ACA expanded the types of entities eligible to receive discounted 340B pricing, although, under the current state of the law, with the exception of children’s hospitals, these newly eligible entities will not be eligible to receive discounted 340B pricing on orphan drugs. In addition, as 340B drug pricing is determined based on AMP and Medicaid rebate data, the revisions to the Medicaid rebate formula and AMP definition described above could cause the required 340B discount to increase.

As noted above, the marketability of any products for a pricing premium. The government has also promoted the use of generics, where available.

The policies of the FDA and foreign regulatory authorities may change and additional government regulations may be enacted which could prevent or delayMolecular receive regulatory approval of our investigational drugs or approval of new diseases for our existing products. We cannot predictcommercial sale may suffer if the likelihood, nature or extent of adverse governmental regulation that might arise from future legislative or administrative action, eithergovernment and third-party payors fail to provide adequate coverage and reimbursement. An increasing emphasis on cost containment measures in the United States or abroad.

Other Government Regulation

Our researchhas increased and development activities use biological and hazardous materials that are dangerous to human health and safety or the environment. We are subject to a variety of federal, state and local laws and regulations governing the use, generation, manufacture, storage, handling and disposal of these materials and wastes resulting from these materials. We are also subject to regulation by the Occupational Safety and Health Administration, or OSHA, the California and federal environmental protection

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agencies and to regulation under the Toxic Substances Control Act. OSHA or the California or federal EPA may adopt regulations that may affect our research and development programs. We are unable to predict whether any agency will adopt any regulations that could have a material adverse effect on our operations. We have incurred, andMolecular expect will continue to incur, capitalincrease the pressure on pharmaceutical pricing. Coverage policies and operating expendituresthird-party reimbursement rates may change at any time. Even if favorable coverage and reimbursement status is attained for one or more products for which Molecular receive regulatory approval, less favorable coverage policies and reimbursement rates may be implemented in the future.

In addition, in most foreign countries, the proposed pricing for a drug must be approved before it may be lawfully marketed. The requirements governing drug pricing and reimbursement vary widely from country to country. For example, the European Union provides options for its member states to restrict the range of medicinal products for which their national health insurance systems provide reimbursement and to control the prices of medicinal products for human use. A member state may approve a specific price for the medicinal product or it may instead adopt a system of direct or indirect controls on the profitability of the company placing the medicinal product on the market. There can be no assurance that any country that has price controls or reimbursement limitations for pharmaceutical products will allow favorable reimbursement and pricing arrangements for any of Molecular’s products. Historically, products launched in the European Union do not follow price structures of the United States and generally prices tend to be significantly lower.

Competition

Molecular competes directly with companies that focus on oncology as well as companies dedicating their resources to novel forms of cancer therapies. Molecular also faces competition from academic research institutions, governmental agencies and various other public and private research institutions. With the proliferation of new drugs and therapies into oncology, Molecular expects to face increasingly intense competition as new technologies become available. Any ETB candidates that Molecular successfully develops and commercializes will compete with existing therapies and new therapies that may become available in the future.

Many of Molecular’s competitors have significantly greater financial, manufacturing, marketing, drug development, technical and human resources than Molecular does. Mergers and acquisitions in the pharmaceutical, biotechnology and diagnostic industries may result in even more resources being concentrated among a smaller number of Molecular’s competitors. Smaller or early-stage companies also may prove to be significant competitors, particularly through collaborative arrangements with large and established companies. These competitors also compete with Molecular in recruiting and retaining top qualified scientific and management personnel and establishing clinical trial sites and patient registration for clinical trials, as well as in acquiring technologies complementary to, or necessary for, Molecular’s programs.

The key competitive factors affecting the success of all of Molecular’s ETB candidates, if approved, are likely to be their efficacy, safety, dosing convenience, price, the effectiveness of companion diagnostics in guiding the use of related therapeutics, the level of generic competition and the availability of reimbursement from government and other coststhird-party payors.

Molecular’s commercial opportunity could be reduced or eliminated if its competitors develop and commercialize products that are safer, more effective, less expensive, more convenient or easier to administer, or have fewer or less severe effects than any products that Molecular may develop. Molecular’s competitors also may obtain FDA, EMA or other regulatory approval for their products more rapidly than Molecular may obtain approval for its products, which could result in Molecular’s competitors establishing a strong market position before Molecular is able to enter the ordinary coursemarket. Even if Molecular’s ETB candidates achieve marketing approval, they may be priced at a significant premium over competitive products if any have been approved by then.

In addition to currently marketed therapies, there are also a number of our businessproducts in complying with these lawslate-stage clinical development directed to the same biological targets as Molecular’s programs, including antibodies, antibody drug conjugates and regulations.bi-specific antibodies.

Revenues and Information About Geographic Areas

We had no revenues forIn the year ended December 31, 2016. All2017, 44% of ourthe Company’s revenues forwere received from entities and organizations located in the yearsUnited States and 56% were received from a Japan entity. In the year ended December 31, 2015, and 2014 resulted100% of the Company’s revenues were received from an organization located in the amortization of upfront and milestone payments received under our former collaboration with Merck KGaA.United States. Further information on our collaboration with Merck KGaA isresearch and development agreements are included in Note 34 to ourthe consolidated financial statements. All of our long-lived assets and IPR&D are maintained in the United States.  

Employees

As of December 31, 2016, we2017, Molecular had 1538 full-time employees. 16 of Molecular’s employees including 6 who holdhave Ph.D. and/, PharmD or M.D. degrees. 8degrees, and 9 of ourMolecular’s employees are engaged in research and development and our remainingactivities. None of Molecular’s employees are management or administrative staff. None of our employees is subject to a collective bargaining agreement. We believeMolecular believes that we haveMolecular has good relations with ourMolecular’s employees.

Our Corporate Information

WeOn August 1, 2017, we completed our business combination with Molecular Templates OpCo, Inc., or what was then known as “Molecular Templates, Inc.” (“Private Molecular”; formerly D5 Pharma Inc., a Delaware corporation incorporated on February 19, 2009), in accordance with the terms of an Agreement and Plan of Merger

and Reorganization (the “Merger Agreement”), dated as of March 16, 2017, by and among us (formerly known as Threshold Pharmaceuticals, Inc. (Nasdaq: THLD) (“Threshold”), Trojan Merger Sub, Inc. (“Merger Sub”), our wholly owned subsidiary, and Private Molecular, pursuant to which Merger Sub merged with and into Private Molecular, with Private Molecular surviving as our wholly owned subsidiary, now “Molecular Templates OpCo,  Inc.” (the “Merger”).

On August 1, 2017, in connection with and prior to the consummation of the Merger, we effected an 11-for-1 reverse stock split of the shares of our common stock. Each outstanding share of Private Molecular common stock was converted into 7.7844 shares of common stock of the post-Merger combined company. As a result, we issued approximately 11.7 million shares of our common stock to the stockholders of Private Molecular in exchange for shares of common stock of Private Molecular. Upon the consummation of the Merger, we changed our name to “Molecular Templates, Inc.” For accounting purposes, Private Molecular is considered to have acquired Threshold in the Merger.

Immediately after the Merger, there were incorporated in Delaware on October 17, 2001. Ourapproximately 18,164,843 shares of our common stock outstanding. Immediately after the Merger, the former Private Molecular stockholders, warrant holders and option holders owned approximately 65.6% of our fully-diluted common stock, with the Threshold’s stockholders and warrant holders immediately prior to the Merger, whose warrants and shares of the common stock remain outstanding after the Merger, owning approximately 34.4% of our fully-diluted common stock.

Molecular and Molecular Templates OpCo, Inc. each have a principal executive offices are locatedoffice at 170 Harbor Way9301 Amberglen Boulevard, Suite 300, South San Francisco 94080. Our100, Austin, Texas 78729 and telephone number is (650) 474-8200.(512) 869-1555.

Available Information

We file electronically with the Securities and Exchange Commission, or SEC, our annual reports on Form 10-K, quarterly reports on Form 10-Q and current reports on Form 8-K pursuant to Section 13(a) or 15(d) of the Exchange Act. The SEC maintains an Internet site that contains reports, proxy information and information statements, and other information regarding issuers that file electronically with the SEC. The address of that website is http://www.sec.gov. The materials are also available at the SEC’s Public Reference Room, located at 100 F Street, Washington, D.C. 20549. The public may obtain information through the public reference room by calling the SEC at 1-800-SEC-0330.

You may obtain a free copy of our annual reports on Form 10-K, quarterly reports on Form 10-Q and current reports on Form 8-K and amendments to those reports on the day of filing with the SEC on our website at http://www.thresholdpharm.comwww.mtem.com or by contacting the Investor Relations Department at our corporate offices by calling (650) 474-8200.(512) 869-1555. The information contained in, or that can be accessed through, our website is not part of, and is not incorporated into, this annual report on Form 10-K.

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We have identified the following risks and uncertainties that may have a material adverse effect on our business, financial condition or results of operations. The risks described below are not the only ones we face. Additional risks not presently known to us or that we currently believe are immaterial may also significantly impair our business operations. Our business could be harmed by any of these risks. TheInvesting in our common stock involves a high degree of risk. You should carefully consider the risks and uncertainties described below and all information contained in this report before you decide to purchase our common stock. If any of the possible adverse events described below actually occurs, we may be unable to conduct our business as currently planned and our financial condition and operating results could be harmed. In addition, the trading price of our common stock could decline due to the occurrence of any of these risks,the events described below, and you may lose all or part of your investment. In assessing these risks, you should refer to the other information contained in this annual reportAnnual Report on Form 10-K, including our consolidated financial statements and related notes.

Risks Related to Our Business

Our strategic transaction with Molecular Templates may not be consummated or may not deliver the anticipated benefits we expect.  

In March 2017, we entered into a Merger Agreement with Molecular Templates pursuant to which the shareholders of Molecular Templates will become the majority owners of Threshold. In addition the proposed $20 million commitment from Longitude is subject to certain conditions, including the closing of the Merger and the Company having secured commitments from additional investors for the purchase of an additional $20 million of such securities (the “Financing”).  The Merger, however, is not conditioned upon the closing of the Financing.  We are devoting substantially allOwnership of our time and resources to consummating the Merger and the Financing, however, there can be no assurance that such activities will result in the consummation of the Merger and the Financing or that such transaction will deliver the anticipated benefits or enhance shareholder value.  We cannot assure you that we will complete the Transaction in a timely manner or at all. The Merger Agreement is subject to many closing conditions and termination rights. If the Merger does not occur, our board of directors may elect to attempt to complete another strategic transaction similar to the Merger and the Financing.  Attempting to complete another similar strategic transaction will be costly and time-consuming, and we cannot make any assurances that a future strategic transaction will occur on terms that provide the same or greater opportunity for potential value to our stockholders, or at all. If we are unable to close another strategic transaction and unable to successfully obtain funding for the continued development of evofosfamide and/or partner TX-3424 or HX4, our board of directors may determine to sell or otherwise dispose of our various assets, and distribute any remaining cash proceeds to our stockholders. In that event, the Company would be required to pay all of its debts and contractual obligations, and to set aside certain reserves for potential future claims, there would be no assurances as to the amount or timing of available cash remaining to distribute to stockholders after paying its obligations and setting aside funds for reserves.

Prior to September 2016, our business was almost entirely dependent on the success of evofosfamide and tarloxotinib, and we have suspended further clinical development of tarloxotonib.

Prior to September 2016, we invested substantially all of our efforts and financial resources in the research and development of evofosfamide and tarloxotinib. In December 2015, we announced topline results from two pivotal Phase 3 clinical trials of evofosfamide: TH-CR-406 conducted by Threshold in patients with soft tissue sarcoma and MAESTRO conducted by Merck KGaA, Darmstadt, Germany (“, or Merck KGaA”), in patients with advanced pancreatic cancer; and that neither trial met its primary endpoint of demonstrating a statistically significant improvement in overall survival.  In March 2017, we received minutes from the Company’s formal meeting with the PMDA indicating that the Company’s analysis of the data from the randomized Phase III study, EMR200592-001 (N=693), conducted under a Special Protocol Agreement with the FDA, and the data from the supporting randomized Phase II study, TH-CR-404 (N=214),would not provide adequate efficacy data to support the submission of a New Drug Application (“JNDA”) for evofosfamide for the treatment of patients with locally advanced unresectable or metastatic pancreatic adenocarcinoma previously untreated with chemotherapy.  In September, 2016, the Company announced that its Phase 2 proof-of-concept trial evaluating tarloxotinib bromide for the treatment of patients with mutant EGFR-positive, T790M-negative advanced non-small cell lung cancer(NSCLC) progressing on an EGFR tyrosine kinase inhibitor (TH-CR-601) did not achieve its primary interim response rate endpoint.

If we are unable to consummate the Merger with Molecular Templates, there can be no assurance that we will conduct drug development activities in the future.  Pharmaceutical product development is a highly speculative undertaking and involves a substantial degree of risk. To date, we have focused substantially all of our efforts on our research and development activities on our lead product candidate, evofosfamide. To date, we have not commercialized any products or generated any revenue from product sales. We are not profitable and have incurred losses in each year since our inception in 2001, and we do not know whether or when we will become profitable. We have only a limited operating history upon which to evaluate our business and prospects. We continue to incur significant development and other expenses related to our ongoing operations. Our net loss for the year ended December 31, 2016 was $24.1 million and as of December 31, 2016, we had an accumulated deficit of $353.5 million. To date, we have financed our operations primarily through the sale of equity securities and debt facilities. The amount of our future net losses will depend, in part, on the rate of our future expenditures and our ability to obtain funding through equity and/or debt financings and strategic collaborations. It will be several years, if ever, before evofosfamide is ready for commercialization.

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Our history of net losses and our expectation of future losses, together with our limited operating history, may make it difficult to evaluate our current business and predict our future performance. In addition, the net losses we incur may fluctuate significantly from quarter to quarter and year to year, such that a period-to-period comparison of our results of operations may not be a good indication of our future performance. In any particular quarter or quarters, our operating results could be below the expectations of securities analysts or investors, which could cause our stock price to decline.

We may not be able to complete the merger, and we may not have sufficient funds to pursue another strategic transaction similar to such merger.

We cannot be sure that we will be able to complete the Merger in a timely manner, or at all. The Merger Agreement is subject to many closing conditions and termination rights.

If the strategic transaction with Molecular Templates is not consummated, we may require substantial additional funding to operate.    

Our future capital requirements will depend on many factors, including:  

Until such time, if ever, as we can generate substantial revenue, we would need to finance our cash needs through a combination of equity offerings, debt financings, government or other third-party funding and licensing or collaboration arrangements. To the extent that we raise additional capital through the sale of equity or convertible debt securities, the ownership interests of our common stockholders will be diluted, and the terms of these securities may include liquidation or other preferences that adversely affect the rights of our common stockholders. Debt financing, if available, may involve agreements that include covenants limiting or restricting our ability to take specific actions, such as incurring additional debt, making capital expenditures or declaring dividends. If we raise additional funds through government or other third-party funding, marketing and distribution arrangements or other collaborations, strategic alliances or licensing arrangements with third parties, we may have to relinquish valuable rights to our technologies, future revenue streams, research programs or product candidates or to grant licenses on terms that may not be favorable to us.

Additional funds may not be available when we need them on terms that are acceptable to us, or at all. If adequate funds are not available to us on a timely basis, we may be required to curtail our operations.

If we do not successfully consummate the strategic transaction with Molecular Templates, our board of directors may decide to pursue a dissolution and liquidation of our company. In such an event, the amount of cash available for distribution to our stockholders will depend heavily on the timing of such liquidation as well as the amount of cash that will need to be reserved for commitments and contingent liabilities.

There can be no assurance that we can successfully consummate the Merger with Molecular Templates.  If the transaction is not completed, our board of directors may decide to pursue a dissolution and liquidation of our company. In such an event, the amount of cash available for distribution to our stockholders will depend heavily on the timing of such decision and, ultimately, such liquidation, since the amount of cash available for distribution continues to decrease as we fund our operations in preparation for the consummation of the transaction with Molecular Templates.  Further, the Merger Agreement with Molecular Templates contains

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certain termination rights for each party, and provides that, upon termination under specified circumstances, we may be required to pay Molecular Templates a termination fee of $750,000 and to reimburse certain fees and expenses incurred by Molecular Templates which would further decrease our available cash resources.  If our board of directors were to approve and recommend, and our stockholders were to approve, a dissolution and liquidation of our company, we would be required under Delaware corporate law to pay our outstanding obligations, as well as to make reasonable provision for contingent and unknown obligations, prior to making any distributions in liquidation to our stockholders. Our commitments and contingent liabilities may include (i) regulatory and clinical obligations remaining under our evofosfamide trial; (ii) obligations under our employment and separation agreements with certain employees that provide for severance and other payments following a termination of employment occurring for various reasons, including a change in control of our company; and (iii) potential litigation against us, and other various claims and legal actions arising in the ordinary course of business.  As a result of this requirement, a portion of our assets may need to be reserved pending the resolution of such obligations. In addition, we may be subject to litigation or other claims related to a dissolution and liquidation of our company. If a dissolution and liquidation were pursued, our board of directors, in consultation with its advisors, would need to evaluate these matters and make a determination about a reasonable amount to reserve. Accordingly, holders of our common stock could lose all or a significant portion of their investment in the event of a liquidation, dissolution or winding up of our company.

If the merger is not completed, and we would need to raise significant capital to support our operations, and successfully develop and complete clinical trials for our existing drug candidate, or acquire and develop other products or product candidates at all or on commercially reasonable terms.

Given the limited development of evofosfamide, our limited cash resources, and the additional capital and resources that would be required to pursue such development, if the Merger is not completed, we could be required to rely on securing a collaborative or strategic arrangement for one of our existing drug candidates to support our operations and our future development and clinical trial costs. Due to our history, limited cash resources, limited operational and management capabilities and the intense competition for pharmaceutical product candidates, even if we generate interest in a collaborative or strategic arrangement to support the further development of one of our drug candidates, we may not be able to enter into a final agreement on commercially reasonable terms, on a timely basis or at all. Proposing, negotiating and implementing an economically viable collaborative or strategic arrangement is a lengthy and complex process. As of December 31, 2016, Threshold had cash and cash equivalents totaling $23.6 million. Threshold believes that its current cash and cash equivalents will only be sufficient to fund its operations through next twelve months. Threshold competes for collaborative arrangements and license agreements with the drug candidates and technology developed by other pharmaceutical and biotechnology companies and academic research institutions. Threshold's competitors may have stronger relationships with third parties with whom they may be interested in collaborating, or which have greater financial, development and commercialization resources and/or more established histories of developing and commercializing products than Threshold. As a result, competitors may have a competitive advantage over Threshold in entering into collaborative arrangements with such third parties. In addition, even if Threshold enters into a collaborative or strategic arrangement, the arrangement may not provide Threshold with sufficient funds to support its operations and there is no assurance that its drug candidates would satisfy the development and/or clinical milestones established in the collaborative or strategic arrangement. Further, any drug candidate Threshold pursues will require additional development and regulatory efforts prior to commercial sale, including extensive clinical testing and approval by the FDA and other non-U.S. regulatory authorities. All product candidates are subject to the risks of failure inherent in pharmaceutical product development, including the possibility that the product candidate will not be shown to be sufficiently safe and effective for approval by regulatory authorities and the possibility that, due to strategic considerations, Threshold will discontinue research or development with respect to a product candidate for which it has already incurred significant expense. Even if the product candidates are approved, Threshold cannot be sure that they would be capable of economically feasible production or commercial success.

If we do not successfully complete the Merger, we will require substantial additional funding in the event  to continue our operations, and will need to curtail operations if we have insufficient capital.

Threshold had cash and cash equivalents of $23.6 million at December 31, 2016. Threshold believes that its current cash and cash equivalents will only be sufficient to fund its operations through next twelve months unless Threshold sells additional shares of its common stock through its ATM Sales Agreement or otherwise.    Based on the development and clinical status of its existing drug candidates, Threshold expects its negative cash flows from operations to continue for the foreseeable future.

As such, if the Merger is not consummated, our future capital requirements will depend on many factors, including:

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There can be no assurance that additional funds will be available when needed from any source or, if available, will be available on terms that are acceptable to us or our stockholders. As a result, if Threshold is unable complete the merger or otherwise raise funds to satisfy its capital needs on a timely basis, there can be no assurance that Threshold will be able to continue to operate its business beyond the next twelve months.

We are substantially dependent on our remaining employees to facilitate the consummation of a strategic transaction.

Our ability to successfully complete a strategic transaction depends in large part on our ability to retain our remaining personnel. However, despite our efforts to retain these members of our management, one or more may terminate their employment with us on short notice. The loss of the services of any of these employees could potentially harm our ability to consummate a strategic transaction, as well as fulfill our reporting obligations as a public company.

We are substantially dependent on our remaining employees to facilitate the consummation of a strategic transaction.

Our ability to successfully complete a strategic transaction depends in large part on our ability to retain our remaining personnel, particularly Harold Selick, our chief executive officer until March 31, 2017 and chairman of the board after March 31, 2017, Wilfred Jaeger, our chief executive officer after March 31, 2017, Kristen Quigley, our vice president of clinical operations, and Joel Fernandes our senior vice president of finance. However, despite our efforts to retain these members of our management, one or more may terminate their employment with us on short notice. The loss of the services of any of these employees could potentially harm our ability to consummate a strategic transaction, as well as fulfill our reporting obligations as a public company.

Risks Related to the Merger 

The exchange ratio is not adjustable based on the market price of the Company’s common stock so the merger consideration at the closing may have a greater or lesser value than at the time the Merger Agreement was signed.

The Merger Agreement has set the exchange ratio for the Molecular Templates common stock, and the exchange ratio is only adjustable upward or downward if the net cash of the Company changes, prior to completion of the Merger. Any changes in the market price of Threshold common stock before the completion of the Merger will not affect the number of shares Molecular Templates security holders will be entitled to receive pursuant to the Merger Agreement.

Failure to complete the Merger may result in us paying a termination fee or reimbursing expenses to Molecular Templates and could harm the price of our common stock.

If the merger is not completed, we are subject to the following risks:

In addition, if the Merger is not consummated and Molecular Templates were to be unable to repay the $2.0 million bridge loan we made to Molecular Templates in connection with the execution of the Merger Agreement, we would be an unsecured creditor of Molecular Templates.  Moreover, our bridge loan is effectively subordinated to Molecular Templates’ secured debt.  In addition, if the Merger Agreement is terminated and our board of directors determines to seek another strategic transaction, there can be no assurance that we will be able to find a partner willing to proscribe equivalent or more attractive value to us than the value proscribed by Molecular Templates in the Merger Agreement.  Any termination or inability to complete the Merger could result in a significant decline in our stock price and could have a material adverse effect on our business. 

The merger may be completed even though material adverse changes may result from the announcement of the merger, industry-wide changes and other causes.

In general, either we or Molecular Templates can refuse to complete the merger if there is a material adverse change affecting the other party between March 16, 2017, the date of the Merger Agreement and the closing. However, certain types of changes do not

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permit either party to refuse to complete the merger, even if such change could be said to have a material adverse effect on us or Molecular Templates, including:

If adverse changes occur and Threshold and Molecular Templates still complete the merger, the combined organization stock price may suffer. This in turn may reduce the value of the merger to the stockholders of Threshold, Molecular Templates or both.

Some Threshold officers and directors have interests in the merger that are different from yours and that may influence them to support or approve the merger without regard to your interests.

Certain officers and directors of Threshold participate in arrangements that provide them with interests in the merger that are different from yours, including, among others, severance benefits, the acceleration of stock option vesting and continued indemnification. For example, in connection with Threshold hiring its executive officers, Threshold entered into customary severance agreements with its executive officers that provide them with cash severance payments, reimbursement for health coverage costs and the acceleration of their outstanding equity awards by 24 months in the event their employment is terminated without cause in connection with or following a change of control of Threshold. Based on the terms of these employment agreements, Threshold's executive officers are contractually entitled to these severance payments, benefits and accelerated vesting because they will be terminated in connection with the consummation of the merger.

Based on the terms of their respective severance agreements, Threshold's executive officers will be entitled to receive an aggregate total value of approximately $2.0 million in severance benefits due to the terminations of their employment upon a change of control to occur in connection with the consummation of the Merger. These interests, among others, may influence the officers and directors of Threshold to support or approve the merger.  

The market price of Threshold common stock following the Merger may decline as a result of the Merger.

The market price of Threshold common stock may decline as a result of the Merger for a number of reasons including if:

Threshold stockholders may not realize a benefit from the Merger commensurate with the ownership dilution they will experience in connection with the merger.

If the combined organization is unable to realize the full strategic and financial benefits currently anticipated from the Merger, Threshold stockholders will have experienced substantial dilution of their ownership interests in their respective companies without receiving any commensurate benefit, or only receiving part of the commensurate benefit to the extent the combined organization is able to realize only part of the strategic and financial benefits currently anticipated from the Merger. Threshold stockholders will experience further dilution upon the closing of the Financing, which is expected to occur immediately following the closing of the Merger.  

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If the merger is not completed, our stock price may decline significantly.Common Stock

The market price of our common stock is subjectexpected to significant fluctuations. Duringbe volatile, and the 12-month period ended December 31, 2016,market price of the salescommon stock may drop.

The market price of our common stock on The NASDAQ Capital Market ranged from a high of $1.22 in September 2016could be subject to a low of $0.27 in February 2016.significant fluctuations.  Market prices for securities of early-stage pharmaceutical, biotechnology and other life sciences companies have historically been particularly volatile.  In addition, the market price of our common stock will likely be volatile based on whether stockholders and investors believe that we can complete the Merger or otherwise raise additional capital to support our operations if the merger is not consummated and another strategic transaction cannot be identified, negotiated and consummated in a timely manner, if at all. The volatilitySome of the market price of Threshold common stock is exacerbated by low trading volume. Additional factors that may cause the market price of our common stock to fluctuate include:

Moreover, the stock markets in general have experienced substantial volatility that has often been unrelated to the operating performance of individual companies.  These broad market fluctuations may also adversely affect the trading price of Thresholdour common stock.

In the past, following periods of volatility in the market price of a company'scompany’s securities, stockholders have often instituted class action securities litigation against the company.those companies.  Such litigation, if instituted, could result in substantial costs and diversion of management attention and resources, which could significantly harm Threshold'sour profitability and reputation.

During the pendency of the Merger, we may not be able to enter intoAdditionally, a business combination with another party at a favorabledecrease in our stock price because of restrictions in the Merger Agreement, which could adversely affect our businesses.

Covenants in the Merger Agreement impede our ability  to make acquisitions, subject to certain exceptions relating to fiduciaries duties, as set forth below, or complete other transactions that are not in the ordinary course of business pending completion of the Merger. As a result, if the Merger is not completed, we may be at a disadvantage to our competitors during that period. In addition, while the Merger Agreement is in effect, we are generally prohibited from, among other things, soliciting, initiating, knowingly encouraging or entering into certain extraordinary transactions, such as a merger, sale of assets or other business combination outside the ordinary course of business, with any third party. Any such transactions could be favorable to our stockholders.  

Certain provisions of the Merger Agreement may discourage third parties from submitting alternative takeover proposals, including proposals that may be superior to the arrangements contemplated by the Merger Agreement.

The terms of the Merger Agreement prohibit each of us from soliciting alternative takeover proposals or cooperating with persons making unsolicited takeover proposals, except in limited circumstances when, among other things, our board of directors determines in good faith that an unsolicited alternative takeover proposal is or is reasonably likely to result in a superior takeover proposal and that failure to cooperate with the proponent of the proposal is reasonably likely to be a breach of the board's fiduciary duties. In addition, if we terminate the Merger Agreement under certain circumstances, including terminating because of a decision of our board of directors to recommend a superior proposal, we would be required to pay to the other party a termination fee equal to $750,000 and the third-party fees and expenses incurred by Molecular Templates. This termination fee may discourage third parties from submitting alternative takeover proposals to Threshold or its stockholders, and may cause our boards of directorscommon stock to be less inclined to recommend an alternative proposal.

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If the conditions to the Merger are not met, the Merger will not occur.

Even if the Merger is approved by the stockholders of Threshold and Molecular Templates, specified conditions must be satisfied or waived to complete the Merger. These conditions are set forth in the Merger Agreement. Threshold and Molecular Templates cannot assure you that all of the conditions will be satisfied. If the conditions are not satisfied or waived, the Merger will not occur or will be delayed, and we may lose some or all of the intended benefits of the Merger.

Risks Related to Drug Discovery, Development and Commercialization

We remain dependent upon the success of evofosfamide. If we are unable to successfully develop and obtain regulatory approval for evofosfamide, our business and future prospects will be severely harmed.  

We have focused our development activities on evofosfamide, and substantially all of our efforts and expenditures continue to be devoted to evofosfamide. Accordingly, our future prospects are dependent on the successful development, regulatory approval and commercialization of evofosfamide. On June 2, 2016, we received preliminary comments from the FDA relating to our request for a meeting indicating that our analysis of the data from the MAESTRO study and the data from a supporting randomized Phase 2 study would not provide adequate efficacy data to support the submission of a new drug application, or NDA, for evofosfamide for the treatment of patients with locally advanced unresectable or metastatic pancreatic adenocarcinoma previously untreated with chemotherapy.  Accordingly, we would be required to successfully conduct one or more additional Phase 3 clinical trials before the FDA would accept any NDA for evofosfamide.  Our inability to submit an NDA to the FDA for evofosfamide in the absence of additional Phase 3 development has significantly harmed our business and future prospects. We have conducted additional analyses of the data from MAESTRO trial and have reviewed and discussed the results of our analyses with the Pharmaceuticals and Medical Devices Agency, or PMDA, in Japan, to determine potential registration pathways. Securing regulatory approval requires the submission of extensive preclinical and clinical data, information about product manufacturing processes and inspection of facilities and supporting information to the regulatory agencies for each therapeutic indication to establish evofosfamide’s safety and efficacy.  Historically, Japan has required that pivotal clinical data submitted in support of a new drug application be performed on a significant population of Japanese patients.  The PMDA may accept U.S. or E.U. patient data when submitted along with a bridging study, but only if it demonstrates that Japanese and non-Japanese subjects react comparably to the product. If we are required to conduct such a bridging study, we would be required to raise additional funding, which we may be unable to do.  The PMDA has substantial discretion in the approval process and may refuse to accept any application or may decide that the data from the MAESTRO trial are insufficient to support the approval of any marketing authorization and that one or more additional clinical trials of evofosfamide would be required to be successfully conducted by us in order to support any such approval, including with respect to the Japanese sub-population we are targeting.  If we are required to successfully conduct and complete any additional clinical trials of evofosfamide in order to support potential approval of evofosfamide in Japan or elsewhere, we would be required to obtain additional capital and there can be no assurances that we would be successful in obtaining the additional funding, whether through new collaborative, partnering or other strategic arrangements or otherwise, necessary to support any additional clinical development of evofosfamide. If our planned discussions with the PMDA do not lead to a registration pathway in Japan that does not require us to conduct any additional clinical trials of evofosfamide, our evofosfamide development strategy would be limited to the planned Phase 1 clinical trial of evofosfamide in combination with immune checkpoint antibodies in collaboration with researchers and clinicians at The University of Texas MD Anderson Cancer Center, and we do not expect to conduct any further development of evofosfamide beyond the planned Phase 1 clinical trial unless such development is part of a new collaborative or partnering arrangement or other strategic transaction or we are otherwise able to raise significant additional funding.  

In any event, the process of obtaining regulatory approvals is expensive, often takes many years, if approval is obtained at all, and can vary substantially based upon the type, complexity and novelty of the product candidates involved. Changes in the enactment of additional statutes or regulations, or changes in regulatory review for each submitted product application, may cause delays in the approval or rejection of an application. In addition, varying interpretations of the data obtained from preclinical and clinical testing could delay, limit or prevent regulatory approval of evofosfamide. Any regulatory approval we may ultimately obtain, from the PMDA or otherwise, may be limited in scope or subject to restrictions or post-approval commitments that render evofosfamide or potential future product candidates not commercially viable. In particular, even if we are able to obtain and maintain regulatory approval of evofosfamide in Japan, the commercial prospects for evofosfamide could be diminished as a result of the more limited patient population in Japan.  If any regulatory approval that we do obtain, including from the PMDA, is delayed or is limited, we may decide not to commercialize the applicable product candidate after receiving the approval.  In addition, in March 2016, we and Merck KGaA agreed to terminate our collaboration and, as a result, we will not receive any clinical development milestones or any other funding from Merck KGaA for the purpose of conducting any further clinical development of evofosfamide. Under our former collaboration with Merck KGaA, Merck KGaA was responsible for 70% of the worldwide development expenses for evofosfamide. If we are unable to obtain sufficient additional funding for the further development of evofosfamide, whether through new collaborative, partnering or other strategic arrangements or otherwise, we may be required to cease further development of our evofosfamide program. Also, issues with the successful and timely transfer of evofosfamide development activities from Merck KGaA could significantly impact our ability to pursue  registration with regulatory authorities and potential partners, and there can be no assurance that such development activities will be successfully transferred to us in a timely manner or at all. For these and other reasons, we cannot assure you that we will be able to advance the development of evofosfamide.  

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In such event, we may be required to abandon the development of evofosfamide and forego any return on our investment from our evofosfamide program, which would severely harm our future prospects and may cause us to cease operations.

Even if we are able to meaningfully advance the development of evofosfamide, the failure of evofosfamide in the future to achieve successful clinical trial endpoints, delays in clinical trial enrollment or events or in the clinical development of evofosfamide, unanticipated adverse side effects related to evofosfamide or any other unfavorable developments or information related to evofosfamide would further significantly harm our business and our future prospects. For example, in January 2016, we announced that an IDSMB concluded that our registrational Phase 2 clinical trial of evofosfamide plus pemetrexed versus pemetrexed alone in patients with non-squamous non-small cell lung cancer was unlikely to reach its primary endpoint of improving overall survival with statistical significance and, as a result, enrollment in this trial was closed and in connection therewith, we determined to cease enrollment in all Threshold-sponsored trials of evofosfamide.  Moreover, evofosfamide is not expected to be commercially available in the near term, if at all. Further, the commercial success of evofosfamide, if any, will depend upon its acceptance by physicians, patients, third party payors and other key decision-makers as a therapeutic and cost effective alternative to currently available products. In any event, if we are unable to successfully develop, obtain regulatory approval for and commercialize evofosfamide, our ability to generate revenue from product sales will be significantly delayed or precluded altogether and our business would be materially and adversely affected, and we may not be able to continue as a going concern.

We currently lack the ability to discover additional prodrug product candidates and we also may not be able to successfully acquire or in-license and develop additional prodrug product candidates or programs suitable for clinical testing, either of which could limit our growth and revenue potential.

Evofosfamide is currently our only product candidate in the clinical development stage and we may be unable to develop additional product candidates suitable for clinical testing. In this regard, as part of our workforce reduction in December 2015 that followed the reported negative results from the two Phase 3 clinical trials of evofosfamide, we eliminated our discovery research activities conducted in-house, which prevents our ability to discover additional prodrug product candidates at this time.  In addition, given the uncertain prospects for evofosfamide, our strategy includes evaluating opportunities to acquire or in-license additional product candidates or development programs that build on our expertise and complement our pipeline. Any growth through acquisition or in-licensing will depend upon the availability of suitable product candidates at favorable prices and upon advantageous terms and conditions. Even if appropriate acquisition or in-licensing opportunities are available, we currently do not have, and may not in the future have, the financial resources necessary to pursue them. In addition, other companies, many of which may have substantially greater financial, marketing and sales resources, compete with us for acquisition or in-licensing opportunities. In addition, we may not be able to realize the anticipated benefits of any acquisition or in-licensing opportunity for a variety of reasons, including the possibility that a product candidate proves not to be safe or effective in later clinical trials or the integration of an acquired or licensed product candidate gives rise to unforeseen difficulties and expenditures. For example, in September 2014, we licensed rights to tarloxotinib, a clinical-stage investigational compound that we evaluated in two Phase 2 proof-of-concept clinical trials. However, based on the interim results of the two Phase 2 proof-of-concept clinical trials, we determined in September 2016 to discontinue any further development of tarloxotinib and we will therefore not realize any return on our investment in tarloxotinib. In any event, any growth through development of additional product candidates will depend principally on our ability to identify, and then to obtain the necessary funding to pursue the acquisition of in-licensing of, additional product candidates on commercially reasonable terms, as well as our ability to develop those product candidates and our ability to obtain additional funding, whether through partnering arrangements or otherwise, to complete the development of, obtain regulatory approval for and commercialize these product candidates. If we are unable to discover or obtain suitable product candidates for development, our growth and revenue potential could be significantly harmed, and we could be required to cease operations.

If we do not establish collaborations or other strategic transactions for our current and potential future product candidates or otherwise raise substantial additional capital, we will likely need to alter, delay or abandon our development and any commercialization plans.

Our strategy includes selectively partnering or collaborating with other pharmaceutical and biotechnology companies to assist us in furthering the development and potential commercialization of our current and potential future product candidates. In this regard, as a result of the termination of our collaboration with Merck KGaA, we are no longer eligible to receive any further milestone payments or other funding from Merck KGaA, includingsatisfy the 70%continued listing standards of worldwide development costs for evofosfamide that were previously borne by Merck KGaA.  Since we are now solely responsible for the further development and commercialization of evofosfamide at our own cost, we are evaluating potential partnering opportunities for evofosfamide, and in this regard, we are currently seeking a pharmaceutical partner for evofosfamide with a commercial presence in oncology in Japan. In this regard, our ability to advance the clinical development of evofosfamide is dependent upon our ability to enter into new partnering, collaborative or other strategic arrangements for evofosfamide, or to otherwise obtain sufficient additional funding for such development. We face significant competition in seeking appropriate strategic partners, and collaborative and partnering arrangements are complex and time consuming to negotiate and document. We may not be successful in entering into new partnering, collaborative or other strategic arrangements with third parties on acceptable terms, or at all. In addition, we are unable to predict when, if ever, we will enter into any additional

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partnering, collaborative or other strategic arrangements because of the numerous risks and uncertainties associated with establishing such arrangements. If we are unable to negotiate new partnering, collaborative or other strategic arrangements, we may have to curtail the development of a particular product candidate, reduce, delay, or terminate its development or one or more of our other development programs, delay its potential commercialization or reduce the scope of our sales or marketing activities or increase our expenditures and undertake development or commercialization activities at our own expense. For example, we may have to cease further development of our evofosfamide program if we are unable to raise sufficient funding for any additional clinical development of evofosfamide through new partnering, collaborative or other strategic arrangements with third parties or other financing alternatives.  In this regard, if we decide to undertake any further development of evofosfamide beyond our planned Phase 1 clinical trial of evofosfamide, we would need to obtain additional funding for such development, either through financing or by entering into partnering, collaborative or other strategic arrangements with third parties for any such further development and we may be unable to do. While we are currently determining third party interest in partnering or acquiring TH-3424 and HX4, we may be unable to partner or divest these assetsin a timely manner, or at all, and therefore may not receive any return on our investment in these assets. If we do not have sufficient funds, we will not be able to advance the development of our product candidates or otherwise bring our product candidates to market and generate product revenues.

Any partnering, collaborative or other strategic arrangements that we establish in the future may not be successful or we may otherwise not realize the anticipated benefits from these arrangements.  In addition, any such future arrangements may place the development and commercialization of our product candidates outside our control, may require us to relinquish important rights or may otherwise be on terms unfavorable to us

We have in the past established and intend to continue to establish partnering, collaborative or other strategic arrangements with third parties to develop and commercialize our product candidates, and these arrangements may not be successful or we may otherwise not realize the anticipated benefits from these arrangements. For example, in March 2016, we and Merck KGaA, mutually agreed to terminate our collaboration for the development and commercialization of our evofosfamide product candidate, and, as a result, we will not receive any additional milestone payments or other funding from Merck KGaA on account of our collaboration with Merck KGaA.  As of the date of this report, we have no ongoing collaborations for the development and commercialization of our product candidates. We may not be able to locate third-party strategic partners to develop and market our product candidates, and we lack the capital and resources necessary to develop our product candidates alone.

Dependence on partnering, collaborative or other strategic arrangements subjects us to a number of risks, including:

Preclinical studies and Phase 1 or 2 clinical trials of our product candidates may not predict the results of subsequent human clinical trials.

Preclinical studies, including studies of our product candidates in animal models of disease, may not accurately predict the results of human clinical trials of those product candidates. In particular, promising animal studies suggesting the efficacy of evofosfamide for the treatment of different types of cancer may not accurately predict the ability of evofosfamide to treat cancer effectively in humans. Evofosfamide, TH-3424 or any other compounds we may develop may be found not to be efficacious in treating cancer, alone or in combination with other agents, when studied in human clinical trials. In addition, we will not be able to commercialize our product candidates until we obtain FDA approval in the United States or approval by comparable regulatory agencies in Japan, Europe and other countries. A number of companies in the pharmaceutical industry, including us and those with greater resources and experience than us, have suffered significant setbacks in Phase 3 clinical trials, even after encouraging results in earlier clinical trials.

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To satisfy FDA, PMDA orother foreign regulatory approval standards for the commercial sale of our product candidates, we must demonstrate in adequate and controlled clinical trials that our product candidates are safe and effective. Success in early clinical trials, including in Phase 1 and Phase 2 clinical trials, does not ensure that later clinical trials will be successful. Initial results from Phase 1 and Phase 2 clinical trials of evofosfamide have in the past not been, and may again in the future not be, confirmed by later analysis or in subsequent larger clinical trials. For example, the results that achieved the primary endpoint for progression-free survival in the Phase 2b trial of evofosfamide in pancreatic cancer did not predict the results of overall survival for patients in the MAESTRO trial. Likewise, the results in the Phase 1/2 trial of evofosfamide in patients with soft tissue sarcoma did not predict the results of overall survival for patients in the 406 trial. In both cases, the 406 trial and the MAESTRO trial failed to meet their primary endpoints of demonstrating a statistically significant improvement in overall survival, based on our analyses for the 406 trial and Merck KGaA’s analyses for the MAESTRO trial, notwithstanding positive results in earlier clinical trials. In addition, in January 2016, we announced that an IDSMB concluded that our registrational Phase 2 clinical trial of evofosfamide plus pemetrexed versus pemetrexed alone in patients with non-squamous non-small cell lung cancer was unlikely to reach its primary endpoint of improving overall survival with statistical significance and, as a result, enrollment in this trial was closed.  As these examples illustrate, despite the results reported in earlier clinical trials for evofosfamide, we do not know whether potential future clinical trials that we may conduct will demonstrate adequate efficacy and safety to result in regulatory approval to market evofosfamide. Our failure to successfully complete any potential future clinical trials and obtain regulatory approval for evofosfamide would materially and adversely affect our business and severely harm our future prospects.

Delays in our potential future clinical trials could result in us not achieving anticipated developmental milestones when expected, increased costs and delay our ability to obtain regulatory approval and commercialize our product candidates.

Delays in the progression of our potential future clinical trials could result in us not meeting previously announced clinical milestones and could materially impact our product development costs and milestone revenue and delay regulatory approval of our product candidates. We do not know whether our potential future clinical trials of evofosfamide, including our planned Phase 1 clinical trial of evofosfamide, will be completed on schedule, if at all. Clinical trials can be delayed for a variety of reasons, including:

Delays in clinical trials can also result from difficulties in enrolling patients in our potential future clinical trials, which could increase the costs or affect the timing or outcome of these clinical trials. This is particularly true with respect to diseases with relatively small patient populations. Timely completion of clinical trials depends, in addition to the factors outlined above, on our ability to enroll a sufficient number of patients, which itself is a function of many factors, including:

If we do not successfully complete our potential future clinical trials on schedule, the price of our common stock may further decline.

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Our product candidates must undergo rigorous clinical testing, the results of which are uncertain and could substantially delay or prevent us from bringing them to market.

Before we can obtain regulatory approval for a product candidate, we must undertake extensive clinical testing in humans to demonstrate safety and efficacy to the satisfaction of the FDA or other regulatory agencies. Clinical trials of new drug candidates sufficient to obtain regulatory marketing approval are expensive and take years to complete.

We cannot be certain of our successfully completing clinical testing within the time frames we have planned or anticipated, or at all. We may experience numerous unforeseen events during, or as a result of, the clinical trial process that could delay or prevent us from receiving regulatory approval or commercializing our product candidates, including the following:

In addition, clinical results are susceptible to varying interpretations that may delay, limit or prevent regulatory approvals. Negative or inconclusive results or adverse safety events, including patient fatalities that may be attributable to our product candidates, during a clinical trial could cause the trial to be terminated or require additional studies. Furthermore, any of our future clinical trials may be overseen by IDMCs or Data and Safety Monitoring Boards, or DSMBs. These independent oversight bodies are comprised of external experts who review the progress of the ongoing clinical trials as well as safety from other trials, and make recommendations concerning a trial’s continuation, modification, or termination based on periodic review of, unblinded data. Any of our potential future clinical trials overseen by an IDMC or DSMB may be discontinued or amended in response to recommendations made by responsible IDMCs or DSMBs based on their review of trial results and an IDMC or DSMB may determine to delay or suspend the trial due to safety or futility findings based on events occurring during a clinical trial. For example, in January 2016, we announced that an IDSMB concluded that our registrational Phase 2 clinical trial of evofosfamide plus pemetrexed versus pemetrexed alone in patients with non-squamous non-small cell lung cancer was unlikely to reach its primary endpoint of improving overall survival with statistical significance and, as a result, enrollment in this trial was closed and in connection therewith, we determined to cease enrollment in all Threshold-sponsored trials of evofosfamide.  The recommended termination or modification of any of our potential future clinical trials by an IDMC or DSMB, could materially and adversely impact the future development of our product candidates, and our business, prospects, operating results, and financial condition may be materially harmed.

We are subject to significant regulatory approval requirements, which could delay, prevent or limit our ability to market our product candidates.

Our research and development activities, preclinical studies, clinical trials and the anticipated manufacturing and marketing of our product candidates are subject to extensive regulation by the FDA, the PMDA and other regulatory agencies in the United States and Japan and by comparable authorities in Europe and elsewhere. We require the approval of the relevant regulatory authorities before we may commence commercial sales of our product candidates in a given market. The regulatory approval process is expensive and time consuming, and the timing of receipt of regulatory approval is difficult to predict. Our product candidates could require a significantly longer time to gain regulatory approval than expected, or may never gain approval. We cannot be certain that, even after expending substantial time and financial resources, we will obtain regulatory approval for any of our product candidates. This was the case with the FDA, which would not accept an NDA based on the data from the MAESTRO study.  A delay or denial of regulatory approval could delay or prevent our ability to generate product revenues and to achieve profitability.

Changes in regulatory approval policies during the development period of any of our product candidates, changes in, or the enactment of, additional regulations or statutes, or changes in regulatory review practices for a submitted product application may cause a delay in obtaining approval or result in the rejection of an application for regulatory approval. Regulatory approval, if obtained, may be made subject to limitations on the indicated uses for which we may market a product. These limitations could adversely affect our potential product revenues. Regulatory approval may also require costly post-marketing follow-up studies. In addition, the

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labeling, packaging, adverse event reporting, storage, advertising, promotion and record-keeping related to the product will be subject to extensive ongoing regulatory requirements. Furthermore, for any marketed product, its manufacturer and its manufacturing facilities will be subject to continual review and periodic inspections by the FDA or other regulatory authorities. Failure to comply with applicable regulatory requirements may, among other things, result in fines, suspensions of regulatory approvals, product recalls, product seizures, operating restrictions and criminal prosecution.

Evofosfamide are based on targeting the microenvironment of solid tumors and some hematological malignancies, which currently is an unproven approach to therapeutic intervention.

Our product candidates are designed to target the microenvironment of solid tumors and some hematological malignancies by, in the case of evofosfamide, harnessing hypoxia for selective toxin activation. We have not nor, to our knowledge, has any other company, received regulatory approval for a drug based on these approaches. We cannot be certain that our approaches will lead to the development of approvable or marketable drugs. Our approaches may lead to unintended, or off-target, adverse effects or may lack efficacy or contribution to efficacy in combination with other anti-cancer drugs.

In addition, the FDA, the PMDA or other regulatory agencies may lack experience in evaluating the safety and efficacy of drugs based on these targeting approaches, which could lengthen the regulatory review process, increase our development costs and delay or prevent commercialization of our current and potential future product candidates.

Our product candidates may have undesirable side effects that prevent or delay their regulatory approval or limit their use if approved.

Anti-tumor drugs being developed by us are expected to have undesirable side effects. For example, in clinical trials of evofosfamide, some patients have exhibited skin and/or mucosal toxicities that have in some cases caused patients to stop or delay therapy. The extent, severity and clinical significance of these or other undesirable side effects may not be apparent initially and may be discovered or become more significant during drug development or even post-approval. These expected side effects or other side effects identified in the course of clinical trials or that may otherwise be associated with our product candidates may outweigh the benefits of our product candidates. Side effects may prevent or delay regulatory approval or limit market acceptance if our products are approved. In this regard, our product candidates may prove to have undesirable or unintended side effects or other characteristics adversely affecting their safety, efficacy or cost effectiveness that could prevent or limit their approval for marketing and successful commercial use, or that could delay or prevent the commencement and/or completion of clinical trials for our product candidates.

We have not yet gained sufficient experience with a commercial formulation of evofosfamide.

The formulation of evofosfamide that was the subject of our prior clinical trials and is the subject of our planned Phase 1 clinical trial was changed to address issues with a prior formulation that was subject to storage and handling requirements that were not suitable for a commercial product. The current formulation of evofosfamide may be suitable for a commercial product, but additional data will be required to verify this and there can be no assurance that we will be able to do so in a timely manner, if at all.Nasdaq Capital Market.  If we are not able to develop a viable commercial formulation of evofosfamide, thenmaintain the requirements for listing on The Nasdaq Capital Market, we maycould be required to conduct additional Phase 3 clinical trials of evofosfamide, or we may need to develop an alternative commercial formulation, either ofdelisted, which could delay, perhaps substantially, our ability to obtain any regulatory approvals of evofosfamide.

The initial clinical formulations developed for evofosfamide or other potential future product candidates may not remain stable throughout the clinical testing phase.

We have limited experience and data on the drug substance synthesis and the initial formulation for evofosfamide. This initial formulation and those of our potential future product candidates may not remain stable during the clinical testing phase.  If these formulations were found to be unstable during clinical testing, we may be required to repeat the initial clinical trials which could increase our costs and delay the development of the applicable product candidate.  We may be required to reformulate these product candidates, including evofosfamide, to improve stability. However, it is possible that we might not be able to develop a formulation of evofosfamide or other future product candidates with adequate quality that meets the need for testing in our clinical trials. We may also be required to perform additional clinical bridging studies which may further delay development. We may also be unable to scale up the manufacturing process to synthesize the current drug substance and current formulations, or the newly developed formulations, any of which could adversely affect our ability to advance the development of, and potentially obtain regulatory approval of, the applicable product candidate.

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Even though we have received orphan drug designation for evofosfamide, we may not receive orphan drug marketing exclusivity for evofosfamide. Even if we obtain orphan drug exclusivity, orphan drug exclusivity would afford us limited protection, and if another party obtains orphan drug exclusivity for the drugs and indications we are targeting, we may be precluded from commercializing our product candidates in those indications.

We have received orphan drug designation for evofosfamide for the treatment of pancreatic cancer in the United States and the European Union or EU. Under the Orphan Drug Act in the United States, the FDA may grant orphan drug designation to drugs intended to treat a rare disease or condition, which is defined by the FDA as a disease or condition that affects fewer than 200,000 individuals in the United States. In the EU, orphan drug designation is provided for a drug that is intended to diagnose, prevent or treat a life-threatening or chronically debilitating condition which affects no more than 5 in 10,000 individuals in the EU (approximately 245,000 individuals) and for which no satisfactory method of diagnosis, prevention or treatment of the condition already exists, or if such method does exist, that the orphan product must be of significant benefit to the patient population over existing products. The company that obtains the first FDA approval for a designated orphan drug indication receives marketing exclusivity for use of that drug for that indication for a period of seven years in the U.S. and 10 years for the EU. The orphan drug designation also allows a waiver or reduction in select regulatory fees. Orphan drug exclusive marketing rights may be lost if the FDA later determines that the request for designation was materially defective, or if the manufacturer is unable to assure sufficient quantity of the drug. Orphan drug designation does not shorten the development or regulatory review time of a drug.

Even if we obtain orphan drug exclusivity for evofosfamide, orphan drug exclusivity may not prevent other market entrants. A different drug, or, under limited circumstances, the same drug may be approved by the FDA for the same orphan indication. The limited circumstances include an inability to supply the drug in sufficient quantities or where a new formulation of the drug has shown superior safety or efficacy. As a result, if evofosfamide were approved for pancreatic cancer, other drugs could still be approved for use in treating the same indications covered by evofosfamide, which could create a more competitive market for us.

Moreover, due to the uncertainties associated with developing pharmaceutical products, we may not be the first to obtain marketing approval for any orphan drug indication. Although we have obtained orphan drug designation, if a competitor obtains regulatory approval for evofosfamide for the same indication we are targeting before we do, we would be blocked from obtaining approval for that indication for seven years, unless our product is a new formulation of the drug that has shown superior safety or efficacy, or the competitor is unable to supply sufficient quantities.

The “fast track” designation for development of any of our product candidates may not lead to a faster development or regulatory review or approval process and it does not increase the likelihood the product candidate will receive regulatory approval.

If a product candidate is intended for the treatment of a serious or life-threatening condition and the product candidate demonstrates the potential to address unmet medical needs for this condition, the drug sponsor may apply for FDA “fast track” designation for a particular indication.  Marketing applications filed by sponsors of product candidates in the fast track process may qualify for priority review under the policies and procedures offered by the FDA, but the fast track designation does not assure any such review. Although Merck KGaA obtained fast track designation for the development of evofosfamide administered in combination with gemcitabine for the treatment of previously untreated patients with metastatic or locally advanced unresectable pancreatic cancer, receipt of fast track designation does not ensure a faster development process, review or FDA approval. In addition, the FDA may withdraw our fast track designation at any time. If we are able to raise sufficient funding for additional clinical development of evofosfamide through new collaborative, partnering or other strategic arrangements with third parties or other financing alternatives, but we lose fast track designation for evofosfamide, the FDA approval process may be delayed. In addition, fast track designation does not guarantee that we will be able to take advantage of the expedited review procedures and does not increase the likelihood that evofosfamide will receive any regulatory approvals.

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Even if we obtain regulatory approvalsfor our current and potential future product candidates, our marketed drugs will be subject to ongoing regulatory review. If we fail to comply with continuing U.S. and foreign regulations, we could lose our approvals to market drugs and our business would be seriously harmed.

Following initial regulatory approval of any drugs we may develop, we will be subject to continuing regulatory review, including review of adverse drug experiences and clinical results that are reported after our drug products become commercially available. This would include results from any post-marketing tests or vigilance required as a condition of approval. The manufacturer and manufacturing facilities used to make any of our drug candidates will also be subject to periodic review and inspection by regulatory agencies, including the PMDA should we be able to obtain regulatory approval of evofosfamide in Japan. If a previously unknown problem or problems with a product or a manufacturing and laboratory facility used by us is discovered, regulatory agencies, including potentially the PMDA, may impose restrictions on that product or on the manufacturing facility, including requiring us to withdraw the product from the market. Any changes to an approved product, including the way it is manufactured or promoted, often require regulatory approval before the product, as modified, can be marketed. Manufacturers of our products, if approved, will be subject to ongoing regulatory agency requirements for submission of safety and other post- market information. If such manufacturers fail to comply with applicable regulatory requirements, a regulatory agency may:

Regulatory authorities may impose significant restrictions on the indicated uses and marketing of pharmaceutical products.

Even if we obtain regulatory approval for evofosfamide, we would be subject to ongoing requirements by the regulatory authorities governing the manufacture, quality control, further development, labeling, packaging, storage, distribution, safety surveillance, import, export, advertising, promotion, recordkeeping and reporting of safety and other post-market information. The safety profile of any product will continue to be closely monitored by regulatory authorities after approval. If the regulatory authorities become aware of new safety information after approval of any of our product candidates, they may require labeling changes or establishment of a REMS or similar strategy, impose significant restrictions on a product’s indicated uses or marketing, or impose ongoing requirements for potentially costly post-approval studies or post-market surveillance. For example, the label ultimately approved for evofosfamide, if it achieves marketing approval, may include restrictions on use. Advertising and promotion of any product candidate that obtains approval will be heavily scrutinized by government agencies and the public. Violations, including promotion of our products for unapproved or off-label uses, are subject to enforcement letters, inquiries and investigations, and civil and criminal sanctions by regulatory authorities. Engaging in impermissible promotion of any approved products for off-label uses could also subject us to false claims litigation under U.S. federal and state statutes and comparable foreign rules and regulations, which could lead to civil and criminal penalties and fines and agreements that materially restrict the manner in which we promote or distribute any approved products.

If we do not lawfully promote any approved products, we may become subject to such litigation and, if we are not successful in defending against such actions, those actions could compromise our ability to become profitable.

We do not have a sales force or marketing infrastructure and may not develop an effective one.

We have no sales experience, as a company. There are risks involved with establishing our own sales and marketing capabilities, as well as entering into arrangements with third parties to perform these services. Developing an internal sales force and function will require substantial expenditures and will be time-consuming, and we may not be able to effectively recruit, train or retain sales personnel. On the other hand, if we enter into arrangements with third parties to perform sales, marketing and distribution services, our product revenues will be lower than if we market and sell any products that we develop ourselves. We may not be able to effectively sell our product candidates, if approved, which could materially harm our business and our financial condition.

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Risks Related to Our Financial Performance and Operations

We have incurred losses since our inception and anticipate that we will continue to incur significant losses for the foreseeable future, and our future profitability is uncertain.

Due to the recognition of the remaining $65.9 million of deferred revenue from our former collaboration with Merck KGaA during the quarter ended December 31, 2015, we reported net income of $43.8 million for the year ended December 31, 2015.  However, during the year ended December 31, 2016 we had a net loss of $24.1 million and we have incurred losses in each of our other years since our inception in 2001, and we expect to incur losses for the foreseeable future. We have devoted and, subject to our ability to obtain additional funding and to otherwise meaningfully advance the development of our product candidates, we expect to continue to devote, substantially all of our resources to the development of evofosfamide. Accordingly, our future prospects remain dependent on the successful development, regulatory approval and commercialization of evofosfamide. In this regard, a substantial portion of our efforts have been devoted to the two pivotal Phase 3 clinical trials of evofosfamide. The failure of the 406 trial and the MAESTRO trial to meet their primary endpoints of demonstrating a statistically significant improvement in overall survival as agreed upon with the FDA, based on our analyses for the 406 trial and Merck KGaA’s analyses for the MAESTRO trial, has significantly depressed our stock price and harmed our future prospects. Likewise, the announcement of our decision to discontinue the development of tarloxotinib following our analysis of the interim results of two Phase 2 proof-of-concept trials of tarloxotinib has depressed our stock price and harmed our future prospects. Although we have conducted our own analyses of the data from MAESTRO trial and have reviewed and discussed the results of our analyses with the PMDA in Japan to determine whether there is an appropriate path forward for submitting marketing authorization applications based on the data from the MAESTRO trial along with a bridging study, the PMDA and other health regulatory authorities may determine that the data from the MAESTRO trial and a bridging study are insufficient to support the approval of any marketing authorizations and that one or more additional clinical trials of evofosfamide would be required to be successfully conducted by us in order to support any such approval, including with respect to the Japanese sub-population we are targeting. If we are required to successfully conduct and complete any additional clinical trials of evofosfamide in order to support potential approval of evofosfamide in Japan, we would be required to obtain additional capital and there can be no assurances that we would be successful in obtaining the additional funding, whether through new collaborative, partnering or other strategic arrangements or otherwise, necessary to support any additional clinical development of evofosfamide. Moreover, apart from the planned Phase 1 clinical trial of evofosfamide, we cannot currently predict whether and to what extent we may continue or increase evofosfamide development activities in future periods, if at all, and what our future cash needs may be for any such activities.  For these and other reasons, we cannot assure you that we will be able to advance the development of evofosfamide.  In such event, we may be required to abandon the development of evofosfamide and forego any return on our investment from our evofosfamide program, which would severely harm our future prospects and may cause us to cease operations.  In any event, we do not expect to generate any revenue from the commercial sales of evofosfamide or any potential future product candidates, including evofosfamide, in the near term, and we expect to continue to have significant losses for the foreseeable future.

To attain ongoing profitability, we will need to develop products successfully and market and sell them effectively, or rely on other parties to do so. We cannot predict when we will achieve ongoing profitability, if at all. We have never generated revenue from the commercial sales of our product candidates, and there is no guarantee that we will be able to do so in the future. If we fail to become profitable, or if we are unable to fund our continuing losses, we would be unable to continue our research and development programs.

We need substantial additional funding and may be unable to raise capital, which could force us to delay, reduce or eliminate our drug discovery, product development and commercialization activities.

Developing drugs, conducting clinical trials, and commercializing products is expensive. Our future funding requirements will depend on many factors, including:

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We believe that our cash, cash equivalents and marketable securities will be sufficient to fund our projected operating requirements for the next twelve months based upon current operating plans and spending assumptions. However, we will need to raise substantial additional capital to meaningfully advance the clinical development of evofosfamide, whether through new collaborative, partnering or other strategic arrangements or otherwise, and to in-license or otherwise acquire and develop additional product candidates or programs.  In particular, our ability to meaningfully advance the clinical development of evofosfamide is dependent upon our ability to enter into new partnering, collaborative or other strategic arrangements for evofosfamide, or to otherwise obtain sufficient additional funding for such development, particularly since we are no longer eligible to receive any further milestone payments or other funding from Merck KGaA for evofosfamide, including the 70% of worldwide development costs for evofosfamide that were previously borne by Merck KGaA.

While we have been able to fund our operations to date, we currently have no ongoing collaborations for the development and commercialization of evofosfamide, and no source of revenue, nor do we expect to generate revenue for the foreseeable future. We also do not have any commitments for future external funding.  Until we can generate a sufficient amount of product revenue, which we may never do, we expect to finance future cash needs through a variety of sources, including:

Our ability to raise additional funds as well as the price and the terms upon which we are able to raise such funds have been severely harmed by the negative results reported from our two pivotal Phase 3 clinical trials of evofosfamide and our decision to discontinue development of tarloxotinib, and may in the future be adversely impacted by the uncertainty regarding the prospects for future development of evofosfamide and our ability to advance the development of evofosfamide or otherwise realize any return on our investments in evofosfamide, if at all. Our ability to raise additional funds and the terms upon which we are able to raise such funds may also be adversely affected by the uncertainties regarding our financial condition, the sufficiencyliquidity of our capital resources,common stock.

Future sales of shares by existing stockholders could cause our abilitystock price to maintain the listingdecline.

If our existing stockholders sell, or indicate an intention to sell, substantial amounts of our common stock on The NASDAQ Capital Market and recent and potential future management turnover. As a result of these and other factors, we cannot be certain that sufficient funds will be available to us or on satisfactory terms, if at all. To the extent we raise additional funds by issuing equity securities, our stockholders may experience significant dilution, particularly given our currently depressed stock price, and debt financing, if available, may involve restrictive covenants. If adequate funds are not available, we may be required to significantly reduce or refocus our operations or to obtain funds through arrangements that may require us to relinquish rights to our product candidates, technologies or potential markets, any of which could result in our stockholders having little or no continuing interest in our evofosfamide program as stockholders or otherwise, or which could delay or require that we curtail or eliminate some or all of our development activities or otherwise have a material adverse effect on our business, financial condition and results of operations.

If we are unable to secure additional funding on a timely basis or on terms favorable to us, we may be required to cease or reduce any product development activities, to conduct additional workforce reductions, to sell some or all of our technology or assets or to merge all or a portion of our business with another entity. Insufficient funds may require us to delay, scale back, or eliminate some or all of our activities, and if we are unable to obtain additional funding, there is uncertainty regarding our continued existence.

Our financial results are likely to fluctuate from period to period, making it difficult to evaluate our stock based on financial performance.

We believe that period-to-period comparisons of our operating results should not be relied upon as predictive of future performance. Our prospects must be considered in light of the risks, expenses and difficulties encountered by companies with no approved pharmaceutical products, and with only one product candidate in clinical development.

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Our success depends in part on attracting, retaining and motivating key personnel and, if we fail to do so, it may be more difficult for us to execute our business strategy. As a small organization we are dependent on key employees and we will need to hire additional personnel to execute our business strategy successfully.

Our success depends on our continued ability to attract, retain and motivate highly qualified management, clinical and scientific personnel and on our ability to develop and maintain important relationships with leading academic institutions, clinicians and scientists. We are highly dependent upon our senior management. The loss of the services of one or more of our other key employees could delay or adversely impact the development of our product candidates.

In December 2015, we announced a workforce reduction constituting approximately two-thirds of our workforce with an additional workforce reduction in September 2016, and as of December 31, 2016, we had only 15 employees. Our success will depend on our ability to retain and motivate remaining personnel and hire additional qualified personnel when required, and our history of implementing workforce reductions, along with the potential for future workforce reductions, may negatively affect our ability to retain and/or attract talented employees. In addition, competition for qualified personnel in the biotechnology field is intense. We face competition for personnel from other biotechnology and pharmaceutical companies, universities, public and private research institutions and other organizations. We may not be able to attract and retain qualified personnel on acceptable terms given the competition for such personnel. If we are unsuccessful in our retention, motivation and recruitment efforts, we may be unable to execute our business strategy.  

In addition, certain members of our management terms were part of our December 2015 and September 2016 workforce reductions, including our former senior vice presidents of regulatory affairs and pharmaceutical development and manufacturing as well as our former Chief Scientific Officer and our former Chief Operating Officer. Management transition inherently causes some loss of institutional knowledge, which can negatively affect strategy and execution and disrupt our ability to successfully manage and grow our business, and our results of operations and financial condition could suffer as a result.

Significant disruptions of information technology systems or breaches of data security could adversely affect our business.

Our business is increasingly dependent on critical, complex and interdependent information technology systems, including Internet-based systems, to support business processes as well as internal and external communications. The size and complexity of our computer systems make them potentially vulnerable to breakdown, malicious intrusion and computer viruses that may result in the impairment of production and key business processes.

In addition, our systems are potentially vulnerable to data security breaches — whether by employees or others — that may expose sensitive data to unauthorized persons. Such data security breaches could lead to the loss of trade secrets or other intellectual property, or could lead to the public exposure of personal information (including sensitive personal information) of our employees, clinical trial patients, customers and others. Such disruptions and breaches of security could have a material adverse effect on our business, financial condition and results of operations.

Our ability to use our net operating loss carryforwards and certain other tax attributes will be limited.

Under Section 382 of the Internal Revenue Code of 1986, as amended, if a corporation undergoes an “ownership change,” generally defined as a greater than 50% change (by value) in its equity ownership over a three-year period, the corporation’s ability to use its pre-change net operating loss carryforwards and other pre-change tax attributes (such as research tax credits) to offset its post- change taxable income or taxes may be limited. Our prior and potential future equity offerings and other changes in our stock ownership, some of which are outside of our control, may have resulted or could in the future result in an ownership change. If a limitation were to apply, utilization of a portion of our domestic net operating loss and tax credit carryforwards could be limited in future periods and a portion of the carryforwards could expire before being available to reduce future income tax liabilities.

Our facilities in California are located near an earthquake fault, and an earthquake or other natural disaster or resource shortage could disrupt our operations.

Important documents and records, such as hard copies of our laboratory books and records for our product candidates, are located in our corporate facilities in South San Francisco, California, near active earthquake zones. In the event of a natural disaster, such as an earthquake, drought or flood, or localized extended outages of critical utilities or transportation systems, we do not have a formal business continuity or disaster recovery plan, and could therefore experience a significant business interruption. In addition, California from time to time has experienced shortages of water, electric power and natural gas. Future shortages and conservation measures could disrupt our operations and could result in additional expense. Although we maintain business interruption insurance coverage, the policy specifically excludes coverage for earthquake and flood.

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Risks Related to Our Dependence on Third Parties

We rely on third parties to manufacture evofosfamide and expect to rely on third parties to manufacture any other potential future product candidates that we may develop. If these parties do not manufacture the active pharmaceutical ingredients or finished drug products of satisfactory quality, in a timely manner, in sufficient quantities or at an acceptable cost, clinical development and commercialization of evofosfamide and any other product candidates we may develop could be delayed.

We do not have our own manufacturing capability for the evofosfamide active pharmaceutical ingredient, or API, or evofosfamide drug product. To date, we have relied on, and we expect to continue to rely on, a limited number of third party contract manufacturers and excipient suppliers for the evofosfamide API and evofosfamide drug product to meet our clinical supply needs of evofosfamide. We have no long-term commitments or commercial supply agreements with any of our evofosfamide suppliers. Our current and anticipated future dependence upon others for the manufacture of our product candidates may adversely affect our ability to develop and commercialize any product candidates on a timely and competitive basis.

We need to have sufficient evofosfamide API and drug product manufactured to meet the clinical supply demands for our clinical trials. If we are not successful in having sufficient quantities of evofosfamide API and drug product manufactured, or if manufacturing is interrupted at our contract manufacturers and excipient suppliers for evofosfamide API and our evofosfamide drug product manufacturers due to regulatory or other reasons, or consume more drug product than anticipated because of a higher than expected trial utilization or have quality issues that limit the utilization of the drug product, we may experience a significant delay in our evofosfamide clinical program. In any event, we will need to order additional evofosfamide API and drug product and we have in the past experienced delays in the receipt of satisfactory drug product, and any additional delays we may experience in the receipt of satisfactory evofosfamide API or drug product could cause significant delays in our potential future evofosfamide clinical trials, which would harm our business. Moreover the need for additional supplies and preparation for registration may require manufacturing process improvements in evofosfamide API and drug product. The manufacturing processes improvements for the evofosfamide API may require facilities upgrades at our suppliers, which may lead to delays or disruption in supply, or delays in regulatory approval of evofosfamide. Changes to the formulation of evofosfamide for our potential future clinical trials may also require bridging studies to demonstrate the comparability of the new formulation with the old. These studies may delay our clinical trials and may not be successful. Even if we are successful in raising the additional capital necessary to meaningfully advance the development of evofosfamide, if we are not successful in procuring sufficient evofosfamide clinical trial material, we may experience a significant delay in our evofosfamide clinical program. Finally, we have not engaged any backup or alternative suppliers for parts of our evofosfamide supply chain for our potential future evofosfamide clinical trials. If we are required to engage a backup or alternative supplier, the transfer of technical expertise and manufacturing process to the backup or alternative supplier would be difficult, costly and time-consuming and would increase the likelihood of a significant delay or interruption in manufacturing or a shortage of supply of evofosfamide.

In any event, additional agreements for more supplies of each of our product candidates, including evofosfamide, will be needed to complete clinical development and/or commercialize them. In this regard, we may need to enter into agreements for additional supplies of evofosfamide to commercialize it or develop such capability itself. We cannot be certain that we can do so on favorable terms, if at all. We will need to satisfy all current good manufacturing practice, or cGMP, regulations, including passing specifications. Our inability to satisfy these requirements could delay our clinical programs and the potential commercialization of evofosfamide if approved for commercial sale.

If evofosfamide or any of our other product candidates is approved by the FDA, the PMDA or other regulatory agencies for commercial sale, we will need to have it manufactured in commercial quantities. It may not be possible to successfully manufacture commercial quantities of evofosfamide or increase the manufacturing capacity for evofosfamide or any of our other product candidates in a timely or economically feasible manner. Prior to commercial launch of evofosfamide, we may be required to manufacture additional validation batches, which the FDA, the PMDA and other regulatory agencies must review and approve. If we are unable to successfully manufacture the additional validation batches or increase the manufacturing capacity for evofosfamide or any other product candidates, the regulatory approval or commercial launch of that product candidate may be delayed, or there may be a shortage of supply which could limit sales.

In addition, if the facility or the equipment in the facility that produces our product candidates is significantly damaged or destroyed, adversely impacted by an action of a regulatory agency or if the facility is located in another country and trade or commerce with or exportation from such country is interrupted or delayed, we may be unable to replace the manufacturing capacity quickly or inexpensively. The inability to obtain manufacturing agreements, the damage or destruction of a facility on which we rely for manufacturing or any other delays in obtaining supply would delay or prevent us from completing our clinical trials and commercializing our current product candidates.

In addition, the evofosfamide formulation includes excipients that might be available from a limited number of suppliers. We have not signed long term supply agreements with these excipient suppliers. We will need to enter into long term supply agreements to

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ensure uninterrupted supply of these excipients to continuously manufacture clinical batches or commercial supplies, which we may be unable to do in a timely or economically feasible manner or at all.

We also expect to rely on contract manufacturers or other third parties to produce sufficient quantities of clinical trial product for any other product candidates that we may develop. It is possible that we might not be able to develop a formulation for evofosfamide with adequate quality that meets the need for testing in our clinical trials. In any event, in order for us to commence any potential future clinical trials of our current and potential future product candidates, including our planned Phase 1 clinical trial of evofosfamide, we need to obtain or have manufactured sufficient quantities of clinical trial product and there can be no assurance that we will be able to obtain sufficient quantities of clinical trial product in a timely manner or at all. Any delay in receiving sufficient supplies of clinical trial product for our potential future studies could negatively impact our development programs.

We have no control over our manufacturers’ and suppliers’ compliance with manufacturing regulations, and their failure to comply could result in an interruption in the supply of our product candidates.

The facilities used by our single source contract manufacturers must undergo an inspection by the FDA, the PMDA and other foreign agencies for compliance with cGMP regulations, before the respective product candidates can be approved in their region. In the event these facilities do not receive a satisfactory cGMP inspection for the manufacture of our product candidates, we may need to fund additional modifications to our manufacturing process, conduct additional validation studies, or find alternative manufacturing facilities, any of which would result in significant cost to us as well as a delay of up to several years in obtaining approval for such product candidate. In addition, our contract manufacturers, and any alternative contract manufacturer we may utilize, will be subject to ongoing periodic inspection by the FDA and corresponding state agencies, the PMDA and other foreign agencies for compliance with cGMP regulations, similar foreign regulations and other regulatory standards. We do not have control over our contract manufacturers’ compliance with these regulations and standards. Any failure by our third-party manufacturers or suppliers to comply with applicable regulations could result in sanctions being imposed on them (including fines, injunctions and civil penalties), failure of regulatory authorities to grant marketing approval of our product candidates, delays, suspension or withdrawal of approvals, warning letters, license revocation, seizures or recalls of product candidates or products, operating restrictions and criminal prosecution.

We expect to rely on third parties to conduct some of our potential future clinical trials, and their failure to perform their obligations in a timely or competent manner may delay development and commercialization of our product candidates.

We may use clinical research organizations to assist in conduct of our clinical trials. There are numerous alternative sources to provide these services. However, we may face delays outside of our control if these parties do not perform their obligations in a timely or competent fashion or if we are forced to change service providers. This risk is heightened for clinical trials conducted outside of the United States, where it may be more difficult to ensure that clinical trials are conducted in compliance with FDA and applicable foreign regulatory requirements. Any third-party that we hire to conduct clinical trials may also provide services to our competitors, which could compromise the performance of their obligations to us. If we experience significant delays in the progress of our future clinical trials, if any, and in our plans to submit NDAs to the FDA and PMDA, the commercial prospects for product candidates could be harmed and our ability to generate product revenue would be delayed or prevented.

We are dependent on Eleison Pharmaceuticals, Inc. to develop and commercialize glufosfamide

We are dependent upon Eleison Pharmaceuticals, Inc., or Eleison to whom we exclusively licensed glufosfamide in October 2009, to develop and commercialize glufosfamide. Any profit sharing or other payments to us under the Eleison license depend almost entirely upon the efforts of Eleison, which may not be able to raise sufficient funds to continue clinical development activities with glufosfamide. Even if Eleison is successful at raising sufficient funding, it may not be successful in developing and commercializing glufosfamide. We may also be asked to provide technical assistance related to the development of glufosfamide, which may divert our resources from other activities. If the Eleison license terminates in such a way that glufosfamide reverts to us and we seek alternative arrangements with one or more other parties to develop and commercialize glufosfamide, we may not be able to enter into such an agreement with another suitable third party or third parties on acceptable terms or at all. In such event, since we have no further development plans for glufosfamide, we may not receive any further return on our investment in glufosfamide.

Risks Related to Our Intellectual Property

Hypoxia-targeted prodrug technology is not a platform technology broadly protected by patents, and others may be able to develop competitive drugs using this approach.

Although we have U.S. and foreign issued patents that cover certain hypoxia- and AKR1C3 -targeted prodrugs, including evofosfamide, respectively, we have no issued patents or pending patent applications that would prevent others from taking advantage of hypoxia-prodrug technology generally to discover and develop new therapies for cancer or other diseases. Consequently, our

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competitors may seek to discover and develop potential therapeutics that operate by mechanisms of action that are the same or similar to the mechanism of action of our hypoxia-prodrug product candidate.

We are dependent on patents and proprietary technology. If we fail to adequately protect this intellectual property or if we otherwise do not have exclusivity for the marketing of our products, our ability to commercialize products could suffer.

Our commercial success will depend in part on our ability to obtain and maintain patent protection sufficient to prevent others from marketing our product candidates, as well as to defend and enforce these patents against infringement and to operate without infringing the proprietary rights of others. We will only be able to protect our product candidates from unauthorized use by third parties to the extent that valid and enforceable patents cover our product candidates or their manufacture or use or if they are effectively protected by trade secrets. If our patent applications do not result in issued patents, or if our patents are found to be invalid, we will lose the ability to exclude others from making, using or selling the inventions claimed therein. We have a limited number of patents and pending patent applications.

The patent positions of pharmaceutical and biotechnology companies can be highly uncertain and involve complex legal and factual questions. No consistent policy regarding the breadth of claims allowed in biotechnology patents has emerged to date in the United States. The laws of many countries may not protect intellectual property rights to the same extent as United States laws, and those countries may lack adequate rules and procedures for defending our intellectual property rights. Changes in either patent laws or in interpretations of patent laws in the United States and other countries may diminish the value of our intellectual property. We do not know whether any of our patent applications will result in the issuance of any patents and we cannot predict the breadth of claims that may be allowed in our patent applications or in the patent applications we may license from others.

The degree of future protection for our proprietary rights is uncertain because legal means afford only limited protection and may not adequately protect our rights or permit us to gain or keep our competitive advantage. For example:

Moreover, an issued patent does not guarantee us the right to practice the patented technology or commercialize the patented product. Third parties may have blocking patents that could be used to prevent us from commercializing our patented products and practicing our patented technology. Our issued patents and those that may be issued in the future may be challenged, invalidated or circumvented, which could limit our ability to prevent competitors from marketing the same or related product candidates or could limit the length of the term of patent protection of our product candidates. In addition, the rights granted under any issued patents may not provide us with proprietary protection or competitive advantages against competitors with similar technology. Furthermore, our competitors may independently develop similar technologies. Moreover, because of the extensive time required for development, testing and regulatory review of a potential product, it is possible that, before any of our product candidates can be commercialized, any related patent may expire or remain in force for only a short period following commercialization, thereby reducing any advantage of the patent. Patent term extensions may not be available for these patents. If we are not able to obtain adequate protection for, or defend, the intellectual property position of evofosfamide or any other potential future product candidates, then we may not be able to retain or attract collaborators to partner our development programs, including evofosfamide. Further, even if we can obtain protection for and defend the intellectual property position of evofosfamide or any potential future product candidates, we or any of our potential future strategic partners still may not be able to exclude competitors from developing or marketing competing drugs. Should this occur, we, and potential future strategic partners may not generate any revenues or profits from evofosfamide or any potential future product candidates, or our revenue or profit potential would be significantly diminished.

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We rely on trade secrets and other forms of non-patent intellectual property protection. If we are unable to protect our trade secrets, other companies may be able to compete more effectively against us.

We rely on trade secrets to protect certain aspects of our technology, especially where we do not believe patent protection is appropriate or obtainable. However, trade secrets are difficult to protect, especially in the pharmaceutical industry, where much of the information about a product must be made public during the regulatory approval process. Although we use reasonable efforts to protect our trade secrets, our employees, consultants, contractors, outside scientific collaborators and other advisors may unintentionally or willfully disclose our information to competitors. Enforcing a claim that a third party illegally obtained and is using our trade secret information is expensive and time consuming, and the outcome is unpredictable. In addition, courts outside the United States may be less willing to or may not protect trade secrets. Moreover, our competitors may independently develop equivalent knowledge, methods and know-how.

If we are sued for infringing intellectual property rights of third parties or if we are forced to engage in an interference proceeding, it will be costly and time consuming, and an unfavorable outcome in that litigation or interference would have a material adverse effect on our business.

Our ability to commercialize our product candidates depends on our ability to develop, manufacture, market and sell our product candidates without infringing the proprietary rights of third parties. Numerous United States and foreign patents and patent applications, which are owned by third parties, exist in the general field of cancer therapies or in fields that otherwise may relate to our product candidates. If we are shown to infringe, we could be enjoined from use or sale of the claimed invention if we are unable to prove that the patent is invalid. In addition, because patent applications can take many years to issue, there may be currently pending patent applications, unknown to us, which may later result in issued patents that our product candidates may infringe, or which may trigger an interference proceeding regarding one of our owned or licensed patents or applications. There could also be existing patents of which we are not aware that our product candidates may inadvertently infringe or which may become involved in an interference proceeding.

The biotechnology and pharmaceutical industries are characterized by the existence of a large number of patents and frequent litigation based on allegations of patent infringement. For so long as our product candidates are in clinical trials, we believe our clinical activities fall within the scope of the exemptions provided by 35 U.S.C. Section 271(e) in the United States, which exempts from patent infringement liability activities reasonably related to the development and submission of information to the FDA. As our clinical investigational drug product candidates progress toward commercialization, the possibility of a patent infringement claim against us increases. While we attempt to ensure that our active clinical investigational drugs and the methods we employ to manufacture them, as well as the methods for their use we intend to promote, do not infringe other parties’ patents and other proprietary rights, we cannot be certain they do not, and competitors or other parties may assert that we infringe their proprietary rights in any event.

We may be exposed to future litigation based on claims that our product candidates, or the methods we employ to manufacture them, or the uses for which we intend to promote them, infringe the intellectual property rights of others. Our ability to manufacture and commercialize our product candidates may depend on our ability to demonstrate that the manufacturing processes we employ and the use of our product candidates do not infringe third-party patents. If third-party patents were found to cover our product candidates or their use or manufacture, we could be required to pay damages or be enjoined and therefore unable to commercialize our product candidates, unless we obtained a license. A license may not be available to us on acceptable terms, if at all.

Risks Related To Our Industry

If our competitors are able to develop and market products that are more effective, safer or more affordable than ours, or obtain marketing approval before we do, our commercial opportunities may be limited.

Competition in the biotechnology and pharmaceutical industries is intense and continues to increase, particularly in the area of cancer treatment. Most major pharmaceutical companies and many biotechnology companies are aggressively pursuing oncology development programs, including traditional therapies and therapies with novel mechanisms of action. Our cancer product candidates face competition from established biotechnology and pharmaceutical companies and from generic pharmaceutical manufacturers. In particular, if approved for commercial sale for pancreatic cancer, evofosfamide would compete with Gemzar®, marketed by Eli Lilly and Company; Tarceva®, marketed by Roche/Genentech and Astellas Oncology; Abraxane® marketed by Celgene; and FOLFIRINOX, which is a combination of generic products that are sold individually by many manufacturers. There may also be product candidates of which we are not aware at an earlier stage of development that may compete with evofosfamide or other potential future product candidates, we may develop. In short, each cancer indication for which we are or may be developing product candidates has a number of established medical therapies with which our candidates will compete. Our evofosfamide product candidate for targeting the tumor hypoxia is likely to be in highly competitive markets and may eventually compete with other therapies offered by companies who are developing or were developing drugs that target tumor hypoxia.

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We also face potential competition from academic institutions, government agencies and private and public research institutions engaged in the discovery and development of drugs and therapies. Many of our competitors have significantly greater financial resources and expertise in research and development, preclinical testing, conducting clinical trials, obtaining regulatory approvals, manufacturing, sales and marketing than we do. Smaller or early-stage companies may also prove to be significant competitors, particularly through collaborative arrangements with large and established pharmaceutical companies.

Our competitors may succeed in developing products that are more effective, have fewer side effects and are safer or more affordable than our product candidates, which would render our product candidates less competitive or noncompetitive. These competitors also compete with us to recruit and retain qualified scientific and management personnel, establish clinical trial sites and patient registration for clinical trials, as well as to acquire technologies and technology licenses complementary to our programs or advantageous to our business. Moreover, competitors that are able to achieve patent protection obtain regulatory approvals and commence commercial sales of their products before we do, and competitors that have already done so, may enjoy a significant competitive advantage.

Our relationships with customers and third-party payors will be subject to applicable anti-kickback, fraud and abuse and other healthcare laws and regulations, which could expose us to criminal sanctions, civil penalties, contractual damages, reputational harm and diminished profits and future earnings.

Healthcare providers, physicians and third-party payors will play a primary role in the recommendation and prescription of any product candidates for which we obtain marketing approval. Our future arrangements with third-party payors and customers may expose us to broadly applicable fraud and abuse and other healthcare laws and regulations that may constrain the business or financial arrangements and relationships through which we would market, sell and distribute our products. As a biotechnology company, even though we do not and will not control referrals of healthcare services or bill directly to Medicare, Medicaid or other third-party payors, federal and state healthcare laws and regulations pertaining to fraud and abuse and patients’ rights are and will be applicable to our business. The laws that may affect our ability to operate include:

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Efforts to ensure that our business arrangements with third parties will comply with applicable healthcare laws and regulations will involve substantial costs. It is possible that governmental authorities will conclude that our business practices may not comply with current or future statutes, regulations or case law involving applicable fraud and abuse or other healthcare laws and regulations. If our operations are found to be in violation of any of these laws or any other governmental regulations that may apply to us, we may be subject to significant civil, criminal and administrative penalties, damages, fines, imprisonment, exclusion from government funded healthcare programs, such as Medicare and Medicaid, and the curtailment or restructuring of our operations. If any physicians or other healthcare providers or entities with whom we expect to do business are found to not be in compliance with applicable laws, they may be subject to criminal, civil or administrative sanctions, including exclusions from government funded healthcare programs.

There is a substantial risk of product liability claims in our business. If we do not obtain sufficient liability insurance, a product liability claim could result in substantial liabilities.

Our business exposes us to significant potential product liability risks that are inherent in the development, manufacturing and marketing of human therapeutic products. Regardless of merit or eventual outcome, product liability claims may result in:

If we succeed in marketing products, product liability claims could result in an FDA or foreign regulatory investigation of the safety or efficacy of our products, our manufacturing processes and facilities or our marketing programs. An FDA or foreign regulatory investigation could also potentially lead to a recall of our products or more serious enforcement actions, or limitations on the indications, for which they may be used, or suspension or withdrawal of approval.

We have product liability insurance that covers our clinical trials up to a $5 million annual aggregate limit. We intend to expand our insurance coverage to include the sale of commercial products if marketing approval is obtained for our product candidates or any other compound that we may develop. However, insurance coverage is expensive and we may not be able to maintain insurance coverage at a reasonable cost or at all, and the insurance coverage that we obtain may not be adequate to cover potential claims or losses.

Even if we receive regulatory approval to market our product candidates, the market may not be receptive to our product candidates upon their commercial introduction, which would negatively affect our ability to achieve profitability.

Our product candidates may not gain market acceptance among physicians, patients, healthcare payors and the medical community. The degree of market acceptance of any approved products will depend on a number of factors, including:

If our product candidates receive regulatory approval but do not achieve an adequate level of acceptance by physicians, patients, healthcare payors and the medical community, we may not generate product revenues sufficient to attain profitability.

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If third-party payors do not cover or adequately reimburse patients for any of our product candidates, if approved for marketing, we may not be successful in selling them.

Our ability to commercialize any approved products successfully will depend in part on the extent to which coverage and reimbursement will be available from governmental and other third-party payors, both in the United States and in foreign markets. Even if we succeed in bringing one or more products to the market, the amount reimbursed for our products may be insufficient to allow us to compete effectively and could adversely affect our profitability. Coverage and reimbursement by a governmental and other third-party payor may depend upon a number of factors, including a governmental or other third-party payor’s determination that use of a product is:

Obtaining coverage and reimbursement approval for a product from each third-party and governmental payor is a time consuming and costly process that could require us to provide supporting scientific, clinical and cost effectiveness data for the use of our products to each payor. We may not be able to provide data sufficient to obtain coverage and reimbursement.

Eligibility for coverage does not imply that any drug product will be reimbursed in all cases or at a rate that allows us to make a profit. Interim payments for new products, if applicable, may also not be sufficient to cover our costs and may not become permanent. Reimbursement rates may vary according to the use of the drug and the clinical setting in which it is used, may be based on payments allowed for lower-cost drugs that are already reimbursed, may be incorporated into existing payments for other products or services and may reflect budgetary constraints and/or Medicare or Medicaid data used to calculate these rates. Net prices for products also may be reduced by mandatory discounts or rebates required by government health care programs or by any future relaxation of laws that restrict imports of certain medical products from countries where they may be sold at lower prices than in the United States.

The health care industry is experiencing a trend toward containing or reducing costs through various means, including lowering reimbursement rates, limiting therapeutic class coverage and negotiating reduced payment schedules with service providers for drug products. The Medicare Prescription Drug, Improvement and Modernization Act of 2003, or MMA, became law in November 2003 and created a broader prescription drug benefit for Medicare beneficiaries. The MMA also contains provisions intended to reduce or eliminate delays in the introduction of generic drug competition at the end of patent or nonpatent market exclusivity. The impact of the MMA on drug prices and new drug utilization over the next several years is unknown. The MMA also made adjustments to the physician fee schedule and the measure by which prescription drugs are presently paid, changing from Average Wholesale Price to Average Sales Price. The effects of these changes are unknown but may include decreased utilization of new medicines in physician prescribing patterns, and further pressure on drug company sponsors to provide discount programs and reimbursement support programs.

In March 2010, the United States Congress enacted the Patient Protection and Affordable Care Act, as amended by the Health Care and Education Reconciliation Act, collectively, the Affordable Care Act, which, among other things, subjected manufacturers to new annual fees and taxes for certain branded prescription drugs and included the following changes to the coverage and payment for drug products under government health care programs:

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Other legislative changes have been proposed and adopted in the United States since the Affordable Care Act was enacted. In August 2011, the Budget Control Act of 2011, among other things, created measures for spending reductions by Congress. A Joint Select Committee on Deficit Reduction, tasked with recommending a targeted deficit reduction of at least $1.2 trillion for the years 2013 through 2021, was unable to reach required goals, thereby triggering the legislation’s automatic reduction to several government programs. This includes aggregate reductions of Medicare payments to providers up to 2% per fiscal year, which went into effect in April 2013 and will remain in effect through 2024 unless additional Congressional action is taken. In January 2013, President Obama signed into law the American Taxpayer Relief Act of 2012, which, among other things, further reduced Medicare payments to several providers, including hospitals and cancer treatment centers. Any reduction in reimbursement from Medicare or other government programs may result in a similar reduction in payments from private payors, which may adversely affect our future profitability.

There have been, and we expect that there will continue to be, federal and state proposals to constrain expenditures for medical products and services, which may affect reimbursement levels for our future products or otherwise result in pricing pressures with respect to our future products. In this regard, we expect further federal and state proposals and healthcare reforms to continue to be proposed to limit the price of, or to curb pricing increases for, prescription drugs, including as a result of negative publicity regarding drug pricing strategies by pharmaceutical companies and pricing increases on pharmaceutical products generally, which could limit the prices that can be charged for our future products, which in turn may limit our commercial opportunity and/or negatively impact revenues from sales of our future products. In addition, the Centers for Medicare & Medicaid Services frequently change product descriptors, coverage policies, product and service codes, payment methodologies and reimbursement values. Third-party payors often follow Medicare coverage policy and payment limitations in setting their own reimbursement rates and may have sufficient market power to demand significant price reductions.

Foreign governments tend to impose strict price controls, which may adversely affect our potential future profitability.

In some foreign countries, particularly in the European Union and Japan, prescription drug pricing is subject to governmental control. In these countries, pricing negotiations with governmental authorities can take considerable time after the receipt of marketing approval for a product. To obtain reimbursement or pricing approval in some countries, we may be required to conduct a clinical trial that compares the cost-effectiveness of our product candidate to other available therapies. If reimbursement of our products is unavailable or limited in scope or amount, or if pricing is set at unsatisfactory levels, our potential future profitability will be negatively affected.

We may incur significant costs complying with environmental laws and regulations, and failure to comply with these laws and regulations could expose us to significant liabilities.

Our research and development activities use biological and hazardous materials that are dangerous to human health and safety or the environment. We are subject to a variety of federal, state and local laws and regulations governing the use, generation, manufacture, storage, handling and disposal of these materials and wastes resulting from these materials. We are also subject to regulation by the Occupational Safety and Health Administration, or OSHA, the California and federal environmental protection agencies and to regulation under the Toxic Substances Control Act. OSHA or the California or federal environmental protection agencies, may adopt regulations that may affect our research and development programs. We are unable to predict whether any agency will adopt any regulations that could have a material adverse effect on our operations. We have incurred, and will continue to incur, capital and operating expenditures and other costs in the ordinary course of our business in complying with these laws and regulations. Although we believe our safety procedures for handling and disposing of these materials comply with federal, state and local laws and regulations, we cannot entirely eliminate the risk of accidental injury or contamination from the use, storage, handling or disposal of hazardous materials. In the event of contamination or injury, we could be held liable for any resulting damages, and any liability could significantly exceed our insurance coverage.

Risks Related to Ownership of our Common Stock

We may not be able to correctly estimate our future operating expenses or our operating expenses may exceed our expectations, which could cause the ownership percentage retained by the Threshold stockholders in the combined organization to be reduced.

Pursuant to the terms of the Merger Agreement, if Threshold’s net cash at the consummation of the merger is less than $12.5 million, the ownership percentage of Threshold’s stockholders, option holders and warrant holders in the combined organization immediately following the consummation of the merger will be reduced.  As of December 31, 2016, we had cash and cash equivalents totaling $23.6 million. However, certain contingent payments related to the Merger, including severance and change of control

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payments payable to our existing and former executive officers, will become due and payable in connection with the closing of the Merger.

Our operating expenses and expenses associated with the Merger and our obligations thereunder may exceed our estimates as a result of a variety of factors, many of which are outside of its control. These factors include:

If we have not correctly estimated our future operating expenses or our operating expenses exceed our expectations, we may be below the $12.5 million level at the time of the merger’s closing, which would result in an adjustment to the exchange ratio in the Merger Agreement such that the ownership percentage retained by the our stockholders in the combined organization immediately following the merger may be reduced.

If we fail to continue to meet all applicable NASDAQ Global Market requirements and NASDAQ determines to delist our common stock, the delisting could adversely affect the market liquidity of our common stock and the markettrading price of our common stock could decrease.

Our common stock is listed ondecline.  The NASDAQ Global Market. In order to maintain our listing, we must meet minimum financial and other requirements, including requirements for a minimum amount of capital, a minimum price per share and continued business operations so that we are not characterized as a “public shell company.” On November 11, 2016, we received a notice from the staff (the “Staff”) of The NASDAQ Stock Market LLC (“Nasdaq”) that, for the previous 30 consecutive business days, the closing bid price for the Company’s common stock was below the $1.00 per share minimum bid price requirement for continued listing on The NASDAQ Capital Market under Nasdaq Listing Rule 5550(a)(2) (the “Bid Price Rule”). In accordance with Nasdaq Listing Rule 5810(c)(3)(A), the Company will have 180 calendar days, or until May 10, 2017, to regain compliance with the Bid Price Rule. To regain compliance with the Bid Price Rule, the closing bid price of the Company’s common stock must be at least $1.00 per share for a minimum of 10 consecutive business days at any time during this 180-day period. If the Company regains compliance with the Bid Price Rule, Nasdaq will provide the Company with written confirmation and will close the matter.  If the Company does not regain compliance with the rule by May 10, 2017, the Company may be eligible for an additional 180 calendar day compliance period. To qualify, the Company would need to meet, on the 180th day of the first compliance period, the continued listing requirement for market value of publicly held shares and all other applicable standards for initial listing on The NASDAQ Capital Market, with the exception of the bid price requirement, and would need to provide written notice of its intention to cure the deficiency during the second compliance period by effecting a reverse stock split, if necessary. In March 2017, the Company’s board of directors approved a reverse stock split, within a range which shall be no less than 5:1 or more than 15:1 of the Company’s common and preferred stock, which would be contingent upon shareholder approval of the Merger and the stock split. However, if it appears to the Staff that the Company will not be able to cure the deficiency, or if the Company is not eligible for a second compliance period, Nasdaq will notify the Company that its common stock will be subject to delisting. In the event of such a notification, the Company may appeal the Staff’s determination to delist its securities, but there can be no assurance the Staff would grant the Company’s request for continued listing.  If we fail to continue to meet all applicable NASDAQ Global Market requirements, Nasdaq may determine to delist our common stock from The NASDAQ Global Market. If our common stock is delisted for any reason, it could reduce the value of our common stock and its liquidity.

If our common stock is delisted as a result of our failure to comply with the Bid Price Requirement or any other Nasdaq continued listing requirement, we would expect our common stock to be tradedperception in the over-the-counter market whichthat these sales may occur could adversely affectalso cause the liquidity of our common stock. Additionally, delisting would substantially impair our ability to raise additional funds to fund our operations, to meaningfully advance the development of evofosfamide and/or to acquire or in-license additional product candidates or development programs, and we could face other significant material adverse consequences, including:  

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Thetrading price of our common stock has been and may continue to be volatile.

The stock markets in general, the markets for biotechnology stocks and, in particular, the stock price of our common stock, have experienced extreme volatility. Further price declines in our common stock could result from general market and economic conditions and a variety of other factors, including:

In the past, following periods of volatility in the market price of a particular company’s securities, litigation has often been brought against that company. Any such lawsuit could consume resources and management time and attention, which could adversely affect our business.

If there are large sales of our common stock, the market price of our common stock could drop substantially. In addition, a significant number of shares of our common stock are subject to issuance upon exercise of outstanding options and warrants, which upon such exercise would result in dilution to our security holders.

If we or our existing stockholders sell a large number of shares of our common stock or the public market perceives that we or our existing stockholders might sell shares of our common stock, the market price of our common stock could decline significantly.decline.  As of December 31, 2016,March 21, 2018, we had 71,560,294 outstanding a total of approximately 27,058,244 shares of common stock, substantially all of which may be sold in the public market without restriction, subject to any affiliate restrictions. On November 2, 2015, we entered into a sales agreement with Cowen, under which we may sell shares of our common stock from time to time through Cowen, as our agent for the offer and sale of the shares, in an aggregate amount not to exceed $50 million. Though our ability to sell shares of common stock through Cowen under our sales agreement with Cowen is practically limited or precluded altogether due to our currently-depressed stock price, to the extent that we sell shares of our common stock pursuant to the sales agreement with Cowen in the future, our stockholders will experience dilution. In addition, a significant number of shares of our common stock are subject to issuance upon the exercise of outstanding options and warrants. On February 18, 2015, we issued warrants to purchase an aggregate of 8,300,000 shares of our common stock, at an initial exercise price per share of $10.86, which exercise price was adjusted to $3.62 on January 21, 2016. In addition, as of

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December 31, 2016, there were 10,941,745 shares of our common stock issuable upon the exercise of outstanding options having a weighted-average exercise price of $3.00 per share. Although we cannot determine at this time how many of the currently outstanding options and warrants will ultimately be exercised, the options and warrants will likely be exercised only if the exercise price is below the market price of our common stock. To the extent that the options and warrants are exercised, additional shares of our common stock will be issued that will be eligible for resale in the public market, which will result in dilution to our security holders.

Failure to maintain effective internal controls in accordance with Section 404 of the Sarbanes-Oxley Act of 2002 could have a material adverse effect on our stock price.

Section 404 of the Sarbanes-Oxley Act of 2002 and the related rules and regulations of the Securities and Exchange Commission, or SEC, require annual management assessments of the effectiveness of our internal control over financial reporting. If we fail to maintain the adequacy of our internal control over financial reporting, as such standards are modified, supplemented or amended from time to time, we may not be able to ensure that we can conclude on an ongoing basis that we have effective internal control over financial reporting in accordance with Section 404 of the Sarbanes-Oxley Act of 2002 and the related rules and regulations of the SEC. If we cannot favorably assess, or our independent registered public accounting firm is unable to provide an unqualified attestation report on, the effectiveness of our internal control over financial reporting, investor confidence in the reliability of our financial reports may be adversely affected, which could have a material adverse effect on our stock price.

Our certificate of incorporation, our bylaws and Delaware law contain provisions that could discourage another company from acquiring us and may prevent attempts by our stockholders to replace or remove our current management.

Provisions of Delaware law, where we are incorporated, our certificate of incorporation and bylaws may discourage, delay or prevent a merger or acquisition that stockholders may consider favorable, including transactions in which you might otherwise receive a premium for your shares. In addition, these provisions may frustrate or prevent any attempts by our stockholders to replace or remove our current management by making it more difficult for stockholders to replace or remove our board of directors. These provisions include:

Claims for indemnification by our directors and officers may reduce our available funds to satisfy successful third-party claims against us and may reduce the amount of money available to us.

Our amended and restated certificate of incorporation and amended and restated bylaws provide that we will indemnify our directors and officers, in each case to the fullest extent permitted by Delaware law.

In addition, as permitted by Section 145 of the Delaware General Corporation Law, or the DGCL, our amended and restated bylaws and our indemnification agreements that we have entered into with our directors and officers provide that: