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Approximate date of commencement of proposed sale to the public:From time to time after the effective date of this registration statement.

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Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b2 of the Exchange Act.

The registrant hereby amends this registration statement on such date or dates as may be necessary to delay its effective date until the registrant shall file a further amendment which specifically states that this registration statement shall thereafter become effective in accordance with section 8(a) of the Securities Act of 1933, as amended, or until the registration statement shall become effective on such date as the Securities and Exchange Commission, acting pursuant to said section 8(a), may determine.

The information contained in this prospectus is not complete and may be changed. We may not sell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This prospectus is not an offer to sell these securities and it is not soliciting an offer to buy these securities in any state where the offer or sale is not permitted.

This prospectus relates to the proposed resale or other disposition of up to 2,518,929 shares of the common stock, par value $0.006 per share, of Marina Biotech, Inc., by the selling stockholders identified in this prospectus. We are not selling any common stock under this prospectus and will not receive any of the proceeds from the sale or other disposition of shares by the selling stockholders.

The selling stockholders or their pledgees, assignees or successors-in-interest may offer and sell or otherwise dispose of the shares of common stock described in this prospectus from time to time through underwriters, broker-dealers or agents, in public or private transactions at prevailing market prices, at prices related to prevailing market prices or at privately negotiated prices. The selling stockholders will bear all commissions and discounts, if any, attributable to the sales of shares. We will bear all other costs, expenses and fees in connection with the registration of the shares. See “Plan of Distribution” beginning on page 27 for more information about how the selling stockholders may sell or dispose of their shares of common stock.

Investing in our common stock involves risks. See “Risk Factors” beginning on page 4.

Our common stock is traded on The Nasdaq Global Market under the symbol “MRNA”. On March ~~21,~~23, 2011, the last reported sale price for our common stock on The Nasdaq Global Market was ~~$0.63~~$0.61 per share. We urge you to obtain current market quotations of our common stock.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus. Any representation to the contrary is a criminal offense.

This prospectus is a part of a registration statement that we filed with the Securities and Exchange Commission, or the SEC, utilizing a “shelf” registration process. Under this shelf registration process, certain selling stockholders may from time to time sell the shares of common stock described in this prospectus in one or more offerings.

We have not authorized anyone to give any information or to make any representation other than those contained or incorporated by reference in this prospectus. You must not rely upon any information or representation not contained or incorporated by reference in this prospectus. The selling stockholders are offering to sell, and seeking offers to buy, shares of our common stock only in jurisdictions where it is lawful to do so. This prospectus does not constitute an offer to sell or the solicitation of an offer to buy any shares other than the registered shares to which they relate, nor does this prospectus constitute an offer to sell or the solicitation of an offer to buy shares in any jurisdiction to any person to whom it is unlawful to make such offer or solicitation in such jurisdiction. You should not assume that the information contained in this prospectus is accurate on any date subsequent to the date set forth on the front of the document or that any information we have incorporated by reference is correct on any date subsequent to the date of the document incorporated by reference, even though this prospectus is delivered or shares are sold on a later date.

Unless the context requires otherwise, in this prospectus the terms “Marina Biotech, Inc.,” “the Company,” “we,” “us” and “our” refer to Marina Biotech, Inc.

This document, as supplemented from time to time, may include product names, trade names and trademarks of other companies. All such product names and trademarks appearing in this document are the property of their respective holders.

Some of the statements in this prospectus and in the documents incorporated herein by reference contain 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. These forward-looking statements reflect our current views with respect to future events or our financial performance, and involve certain known and unknown risks, uncertainties and other factors, including those identified below and throughout this prospectus, those discussed in Item 1A of our Annual Report on Form 10-K for the fiscal year ended December 31, 2010 under the heading “Risk Factors,” and those discussed in our other filings with the Securities and Exchange Commission, which may cause our or our industry’s actual or future results, levels of activity, performance or achievements to differ materially from those expressed or implied by any forward-looking statements or from historical results. We intend such forward-looking statements to be covered by the safe harbor provisions for forward-looking statements contained in Section 27A of the Securities Act and Section 21E of the Exchange Act. Forward-looking statements include information concerning our possible or assumed future results of operations and statements preceded by, followed by, or that include the words “may,” “will,” “could,” “would,” “should,” “believe,” “expect,” “plan,” “anticipate,” “intend,” “estimate,” “predict,” “potential” or similar expressions.

Forward-looking statements are inherently subject to risks and uncertainties, many of which we cannot predict with accuracy and some of which we might not even anticipate. Although we believe that the expectations reflected in such forward-looking statements are based upon reasonable assumptions at the time made, we can give no assurance that such expectations will be achieved. Future events and actual results, financial and otherwise, may differ materially from the results discussed in the forward-looking statements. Readers are cautioned not to place undue reliance on these forward-looking statements. We undertake no obligation to publicly update or revise any forward-looking statements after the date of this prospectus or to conform them to actual results, new information, future events or otherwise, except as otherwise required by securities and other applicable laws.

The following factors, among others, could cause our or our industry’s future results to differ materially from historical results or those anticipated:

our ability to obtain additional funding for our company;

our ability to attract and/or maintain manufacturing, research, development and commercialization partners;

the ability of our company and/or a partner to successfully complete product research and development, including pre-clinical and clinical studies and commercialization;

the ability of our company and/or a partner to obtain required governmental approvals, including product and patent approvals;

the ability of our company and/or a partner to develop and commercialize products prior to, and that can compete favorably with those of, our competitors;

the timing of costs and expenses related to our research and development programs;

the timing and recognition of revenue from milestone payments and other sources not related to product sales;

our ability to attract and retain our key officers and employees;

costs associated with any product liability claims, patent prosecution, patent infringement lawsuits and other lawsuits; and

our ability to maintain our listing on The Nasdaq Global Market.

These factors are the important factors of which we are currently aware that could cause actual results, performance or achievements to differ materially from those expressed in any of our forward-looking statements. We operate in a continually changing business environment, and new risk factors emerge from time to time. Other unknown or unpredictable factors also could have material adverse effects on our future results, performance or achievements. We cannot assure you that projected results or events will be achieved or will occur.

We are a biotechnology company focused on the discovery, development and commercialization of oligonucleotide therapies based on gene silencing approaches such as RNA interference (“RNAi”) and blocking messenger RNA (mRNA) transcription. Our goal is to improve human health through the development of these nucleic acid-based therapeutics as well as the drug delivery technologies that together provide superior treatment options for patients. We have multiple proprietary technologies integrated into a broad oligonucleotide-based drug discovery platform, with the capability to deliver these novel therapeutics via systemic, local and oral administration to target a wide range of human diseases based on the unique characteristics of the cells and organs involved in each disease.

Our pipeline includes a clinical program in Familial Adenomatous Polyposis (FAP) and two preclinical programs in malignant ascites and bladder cancer, respectively. In February 2011, we entered an exclusive agreement with Debiopharm Group for the development and commercialization of the bladder cancer program.

Our team of approximately 30 scientists brings expertise in molecular and cellular biology, microbiology, oligonucleotide, nucleoside, lipid, peptide and alkylated amino acid chemistry, pharmacology, bioinformatics, pre-clinical and clinical development, regulatory affairs and quality control, in addition to an experienced pharmaceutical management team.

In addition to our own, internally developed technologies, we strategically in-license and further develop nucleic acid- and delivery-related technologies, forming an integrated drug discovery platform. We are currently employing our platform for the discovery of multiple nucleic-based therapeutics including RNAi-, microRNA- and single stranded oligonucleotide-based drugs.

Our business strategy is two-fold. First, we strive to establish collaborations and strategic partnerships with pharmaceutical and biotechnology companies in the area of nucleic acid-based therapeutics to: (1) generate revenue and non-dilutive financing; (2) gain access to technical resources; and (3) further validate our drug discovery platforms. Secondly, we expect to advance our own pipeline of nucleic acid-based therapeutics as a foundation upon which to improve all aspects of our drug discovery platform and to have the opportunity to commercialize drug therapies. In terms of collaborations and strategic partnerships, the Debiopharm Group is fully funding the development of the bladder cancer program using our proprietary DiLA² delivery technology for local administration, which includes the potential for significant milestones, and ProNAi Therapeutics, a licensee of certain of our technology, is funding their Phase 1 clinical trial using our proprietary SMARTICLES^® delivery technology for systemic administration, which does not provide any financial benefit to us but continues to validate and advance our SMARTICLES^® delivery technology. With these relationships financing the advancement of several of our small interfering RNA (siRNA) proprietary delivery technologies, we are focusing resources on the Phase 1b/2a clinical trial of CEQ508 in Familial Adenomatous Polyposis (FAP) as well as the development of our Conformationally Restricted Nucleotide technology (CRN) for the development of single-stranded oligonucleotide therapies.

In 2010 we entered into five early collaborative efforts (a sixth had been initiated in 2009) with major pharmaceutical companies and a biotechnology company to evaluate our DiLA² and SMARTICLES delivery technologies for local and systemic delivery of siRNA. Four of the six efforts continued into 2011, and our goal continues to be the establishment of a strategic partnership with at least one of these companies in 2011. We expect to structure certain of our collaborative agreements to receive upfront non-refundable payments, research and development funding, milestone payments and royalties on commercial sales of products.

With respect to collaborations and strategic partnerships, our concept is to provide multiple therapeutic options based on a partner’s target and indication. We can apply our broad capabilities to pursue the most appropriate nucleic acid therapeutic approach to a specific, often undruggable, target for a specific indication. Each approach, i.e. RNAi, microRNA or single-strand oligonucleotide, has its advantages and disadvantages, and we can utilize our broad capabilities to screen across multiple modalities to identify the most effective therapeutic. We believe this capability makes us extremely unique in the sector.

In 2010, we acquired Cequent Pharmaceuticals, Inc. and itsTransKingdom RNA^™ interference (tkRNAi) platform and FAP clinical program, the intellectual property related to the CRN technology from Valeant Pharmaceuticals and the intellectual property related to SMARTICLES from Novosom. Additionally, we licensed one of our nasal legacy assets, carbetocin, to Cypress Biosciences.

In order to protect our innovations, which encompass a broad platform of both nucleic acid constructs and delivery technologies, as well as the drug products that may emerge from that platform; we aggressively continue to build upon our extensive and enabling intellectual property (“IP”) estate.

We believe we have established ourselves as a leading nucleic acid-based therapeutics company by leveraging our broad and proven expertise to create an industry-leading integrated nucleic acid-based drug discovery platform, which is protected by a strong IP position and validated through licensing agreements with two large international pharmaceutical companies, our FAP phase 1b/2a clinical trial, the bladder cancer research and license agreement with Debiopharm Group and the phase 1 ProNAi trial using our SMARTICLES delivery technology.

We were incorporated in Delaware on September 23, 1983. Our principal executive offices are located at 3830 Monte Villa Parkway, Bothell, Washington 98021, and our telephone number is (425) 908-3600. We maintain an Internet website at www.marinabiotech.com. We have not incorporated by reference into this prospectus the information in, or that can be accessed through, our website, and you should not consider it to be a part of this prospectus.

Before you decide whether to purchase any of our common stock, in addition to the other information in this prospectus, you should carefully consider the risk factors set forth below and under the heading “Risk Factors” in our most recent Annual Report on Form 10-K, which is incorporated by reference into this prospectus, as the same may be updated from time to time by our future filings under the Securities Exchange Act of 1934, as amended. Additional risks and uncertainties of which we are unaware or that we believe are not material at the time could also materially adversely affect our business, financial condition or results of operations. In any case, the value of our securities could decline, and you could lose all or part of your investment. For more information, see the sections entitled “Incorporation by Reference” and “Forward-Looking Statements” elsewhere in this prospectus.

Risks Relating to being an Early State Drug Development Company and Managing Growth

We have no history of profitability and there is a potential for fluctuation in operating results.

We have experienced significant operating losses since inception and have an accumulated deficit of $290.8 million at December 31, 2010. In the third quarter of 2008 we suspended all research and clinical development of our intranasal programs and incurred a restructuring charge to exit a facility which was used primarily for our intranasal activities. As of September 30, 2008, our accumulated deficit, which was primarily related to clinical development of our intranasal programs, was approximately $241.8 million. We currently have no revenues from product sales and will not have any such revenues unless and until a marketable product is successfully developed, receives regulatory approvals, and is successfully manufactured and distributed to the market. We expect to continue to experience losses for the foreseeable future. See “Forward-Looking Statements”.

We are developing products based on RNA interference technology. The process of developing such products requires significant research and development efforts, including basic research, pre-clinical and clinical development, and regulatory approval. These activities, together with our sales, marketing, general and administrative expenses, have resulted in operating losses in the past, and there can be no assurance that we can achieve profitability in the future. Our ability to achieve profitability depends on our ability, alone or with our collaborators, to develop our drug candidates, conduct pre-clinical development and clinical trials, obtain necessary regulatory approvals, and manufacture, distribute, market and sell our drug products. We cannot assure you that we will be successful at any of these activities or predict if or when we will ever become profitable.

We do not generate operating income and will require additional financing in the future. If additional capital is not available, we may have to curtail or cease operations.

Our business currently does not generate the cash that is necessary to finance our operations. We incurred net losses of approximately $8.0 million in 2009 and $27.8 million in 2010. Subject to the success of our research and development programs and potential licensing or partnering transactions, we will need to raise significant additional capital to:

fund research and development activities relating to our RNAi drug discovery platform and the development of our product candidates, including clinical and pre-clinical trials;

obtain regulatory approval for our product candidates;

protect our intellectual property;

attract and retain highly-qualified scientists;

respond effectively to competitive pressures; and

acquire complementary businesses or technologies.

the scope, duration and expenditures associated with our research and development;

continued scientific progress in these programs;

the outcome of potential partnering or licensing transactions, if any;

competing technological developments;

our proprietary patent position, if any, in our products; and

the regulatory approval process for our products.

We believe that our existing cash should be sufficient to fund our operations into the second quarter of 2011. We may seek to raise necessary funds through public or private equity offerings, debt financings or additional strategic alliances and licensing arrangements. We may not be able to obtain additional financing on terms favorable to us, if at all. General market conditions may make it very difficult for us to seek financing from the capital markets, and the terms of any financing may adversely affect the holdings or the rights of our stockholders. For example, if we raise additional funds by issuing equity securities, further dilution to our stockholders will result. In addition, as a condition to providing additional funds to us, future investors may demand, and may be granted, rights superior to those of existing stockholders. Debt financing, if available, may involve restrictive covenants that could limit our flexibility in conducting future business activities and, in the event of insolvency, would be paid before holders of equity securities received any distribution of corporate assets. We may be required to relinquish rights to our technologies or drug candidates, or grant licenses on terms that are not favorable to us, in order to raise additional funds through alliance, joint venture or licensing arrangements. If adequate funds are not available, we may have to delay, reduce or eliminate one or more of our research or development programs or reduce overall overhead expenses. These actions would likely reduce the market price of our common stock.

Our independent registered public accounting firm has expressed substantial doubt about our ability to continue as a going concern.

Our independent registered public accounting firm, in its audit opinion issued in connection with our consolidated balance sheets as of December 31, 2010 and 2009 and our consolidated statements of operations, stockholders’ equity (deficit) and cash flows for the years ended December 31, 2010 and 2009, has expressed substantial doubt about our ability to continue as a going concern given our net losses, accumulated deficit and negative cash flows. The corresponding consolidated financial statements were prepared on the basis of a going concern, which contemplates the realization of assets and the satisfaction of liabilities and commitments in the normal course of business, and accordingly do not contain any adjustments which may result due to the outcome of this uncertainty.

If we lose our key personnel, or if we are unable to attract and retain additional personnel, then we may be unable to successfully develop our business.

If we are unable to retain one or more of our executive officers, including J. Michael French, our President and Chief Executive Officer, Peter S. Garcia, our Chief Financial Officer and Secretary, Dr. Barry Polisky, our Chief Scientific Officer, or any of our other key managers or key technical personnel, our business could be seriously harmed. We have entered into employment agreements with Messrs. French and Garcia and with Dr. Polisky. Whether or not a member of management has executed an

employment agreement, there can be no assurance that we will be able to retain our key managers or key technical personnel or replace any of them if we lose their services for any reason. Although we make a significant effort and allocate substantial resources to recruit candidates, competition for competent managers and technical personnel is intense. Failure to attract and retain our key personnel may compromise our ability to negotiate and enter into additional collaborative arrangements, delay our ongoing discovery research efforts, delay pre-clinical or clinical testing of our product candidates, delay the regulatory approval process or prevent us from successfully commercializing our product candidates. In addition, if we have to replace any of these individuals, we may not be able to replace knowledge that they have about our operations.

We may encounter difficulties managing our growth, which could adversely affect our business.

We currently have approximately 45 full-time-equivalent employees, and we expect that as we seek to increase the number of product candidates we are developing we will need to expand our operations in the future. If our business grows, it may place a strain on us, our management and our resources. Our ability to effectively manage our operations, relationships, growth and various projects requires us to continue to improve our operational, financial and management controls, and our reporting systems and procedures, and to attract and retain sufficient numbers of talented employees. We may not be able to successfully implement these tasks on a larger scale and, accordingly, we may not achieve our research, development and commercialization goals. If we do not improve our operational, financial and management information systems, or fail to effectively monitor or manage our growth, our business could suffer significantly.

If we make strategic acquisitions, we will incur a variety of costs and might never realize the anticipated benefits.

Despite our acquisition of Cequent Pharmaceuticals, Inc. in July 2010, we have limited experience in independently identifying acquisition candidates and integrating the operations of acquisition candidates with our company. If appropriate opportunities become available, we might attempt to acquire approved products, additional drug candidates, technologies or businesses that we believe are a strategic fit with our business. If we pursue any transaction of that sort, the process of negotiating the acquisition and integrating an acquired product, drug candidate, technology or business might result in operating difficulties and expenditures and might require significant management attention that would otherwise be available for ongoing development of our business, whether or not any such transaction is ever consummated. Moreover, we might never realize the anticipated benefits of any acquisition. Future acquisitions could result in potentially dilutive issuances of equity securities, the incurrence of debt, contingent liabilities, or impairment expenses related to goodwill, and impairment or amortization expenses related to other intangible assets, which could harm our financial condition.

Failure of our internal control over financial reporting could harm our business and financial results.

Our management is responsible for establishing and maintaining adequate internal control over financial reporting. Internal control over financial reporting is a process to provide reasonable assurance regarding the reliability of financial reporting for external purposes in accordance with accounting principles generally accepted in the United States. Internal control over financial reporting includes maintaining records that in reasonable detail accurately and fairly reflect our transactions; providing reasonable assurance that transactions are recorded as necessary for preparation of the financial statements; providing reasonable assurance that receipts and expenditures of our assets are made in accordance with management authorization; and providing reasonable assurance that unauthorized acquisition, use or disposition of our assets that could have a material effect on the financial statements would be prevented or detected on a timely basis. Because of its inherent limitations, internal control over financial reporting is not intended to provide absolute assurance that a misstatement of our financial statements would be prevented or detected. Our growth and entry into new products, technologies and markets will place significant additional pressure on our system of internal control over financial reporting. Any failure to maintain an effective system of internal control over financial reporting could limit our ability to report our financial results accurately and timely or to detect and prevent fraud.

Despite the implementation of security measures, our internal computer systems and those of our contractors and consultants are vulnerable to damage from computer viruses, unauthorized access, natural disasters, terrorism, war and telecommunication and electrical failures. Such events could cause interruption of our operations. For example, the loss of pre-clinical trial data or data from completed or ongoing clinical trials for our product candidates could result in delays in our regulatory filings and development efforts and significantly increase our costs. To the extent that any disruption or security breach were to result in a loss of or damage to our data, or inappropriate disclosure of confidential or proprietary information, we could incur liability and the development of our product candidates could be delayed.

RNAi-based drug development is unproven and may never lead to marketable products.

Our future success depends on the successful development of products based on RNAi technology. Neither we nor any other company has received regulatory approval to market therapeutics utilizing siRNAs. The scientific discoveries that form the basis for our efforts to discover and develop new siRNA drugs are relatively new. The scientific evidence to support the feasibility of developing drugs based on these discoveries is both preliminary and limited. Skepticism as to the feasibility of developing RNAi therapeutics has been expressed in scientific literature.

Relatively few product candidates based on RNAi technology have ever been tested in animals or humans, none of which have received regulatory approval. We currently have only limited data suggesting that we can introduce typical drug-like properties and characteristics into siRNAs, such as favorable distribution within the body or tissues or the ability to enter cells and exert their intended effects. In addition, RNA-based compounds may not demonstrate in patients the chemical and pharmacological properties ascribed to them in laboratory studies, and they may interact with human biological systems in unforeseen, ineffective or harmful ways. We may make significant expenditures trying to develop RNA-based technologies without success. As a result, we may never succeed in developing a marketable product. If we do not successfully develop and commercialize drugs based upon our RNA-based drug candidates, we may not become profitable and the value of our common stock will likely decline.

Further, our focus solely on RNAi technology for developing drugs, as opposed to multiple, more proven technologies for drug development, increases the risks associated with the ownership of our common stock. If we are not successful in developing a product candidate using RNAi technology, we may be required to change the scope and direction of our product development activities. In that case, we may not be able to identify and implement successfully an alternative product development strategy.

All of our programs, other than our program for CEQ508, are in pre-clinical studies or early stage research. If we are unable to develop and commercialize our product candidates, our business will be adversely affected.

A key element of our strategy is to discover, develop and commercialize a portfolio of new products. We are seeking to do so through our internal research programs and intend to explore strategic collaborations for the development of new products. Whether or not any product candidates are ultimately identified, research programs to identify new disease targets and product candidates require substantial technical, financial and human resources. Our research programs may initially show promise in identifying potential product candidates, yet fail to yield a successful commercial product for many reasons, including the following:

competitors may develop alternatives that render our product candidates obsolete;

a product candidate may not have a sustainable intellectual property position in major markets;

a product candidate may, after additional studies, be shown to have harmful side effects or other characteristics that indicate it is unlikely to be effective;

a product candidate may not receive regulatory approval;

a product candidate may not be capable of production in commercial quantities at an acceptable cost, or at all; or

a product candidate may not be accepted by patients, the medical community or third-party payors.

Upon entering into clinical trials, clinical trials of our product candidates would be expensive and time-consuming, and the results of any of these trials would be uncertain.

Our research and development programs are at an early stage. Before obtaining regulatory approval for the sale of our product candidates, we must conduct, at our own expense, extensive pre-clinical tests and clinical trials to demonstrate the safety and efficacy in humans of our product candidates. Pre-clinical and clinical testing in patients is a long, expensive and uncertain process, and the historical failure rate for product candidates is high. The length of time generally varies substantially according to the type of drug, complexity of clinical trial design, regulatory compliance requirements, intended use of the drug candidate and rate of patient enrollment for the clinical trials.

A failure of one or more of our pre-clinical studies or clinical trials can occur at any stage of testing. We may experience numerous unforeseen events during, or as a result of, the pre-clinical testing and the clinical trial process that could delay or prevent our ability to receive regulatory approval or potentially commercialize our product candidates, including:

regulators may not authorize us to commence a clinical trial or conduct a clinical trial at a prospective trial site;

our pre-clinical tests or clinical trials may produce negative or inconclusive results, and we may decide, or a regulator may require us, to conduct additional pre-clinical testing or clinical trials, or we may abandon projects that we previously expected to be promising;

enrollment in our clinical trials may be slower than we anticipate or participants may drop out of our clinical trials at a higher rate than we anticipate, resulting in significant delays;

our third party contractors may fail to comply with regulatory requirements or meet their contractual obligations to us in a timely manner;

our product candidates may have very different chemical and pharmacological properties in humans than in laboratory testing and may interact with human biological systems in unforeseen, ineffective or harmful ways;

we might have to suspend or terminate our clinical trials if the participants are being exposed to unacceptable health risks;

regulators, including the FDA, may require that we hold, suspend or terminate clinical research for various reasons, including noncompliance with regulatory requirements;

the cost of our clinical trials may be greater than we anticipate;

the supply or quality of our drug candidates or other materials necessary to conduct our clinical trials may be insufficient or inadequate; and

effects of product candidates may not have the desired effects or may include undesirable side effects or the product candidates may have other unexpected characteristics.

Further, even if the results of our pre-clinical studies or clinical trials are initially positive, it is possible that we will obtain different results in the later stages of drug development or that results seen in clinical trials will not continue with longer term treatment. Drugs in late stages of clinical development may fail to show the desired safety and efficacy traits despite having progressed through initial clinical testing. For example, positive results in early Phase 1 or Phase 2 clinical trials may not be repeated in larger Phase 2 or Phase 3 clinical trials. All of our potential drug candidates are prone to the risks of failure inherent in drug development. The clinical trials of any or all of our drugs or drug candidates could be unsuccessful, which would prevent us from commercializing these drugs. The FDA conducts its own independent analysis of some or all of the pre-clinical and clinical trial data submitted in a regulatory filing and often comes to different and potentially more negative conclusions than the analysis performed by the drug sponsor. Our failure to develop safe, commercially viable drugs approved by the FDA would substantially impair our ability to generate revenues and sustain our operations and would materially harm our business and adversely affect our stock price. In addition, significant delays in pre-clinical studies and clinical trials will impede our ability to seek regulatory approvals, commercialize our drug candidates and generate revenue, as well as substantially increase our development costs.

Even if we obtain regulatory approvals, 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 materially adversely affected.

Following any initial FDA or foreign regulatory approval of any drugs we may develop, we will also be subject to continuing regulatory review, including the review of adverse drug experiences and clinical results that are reported after our drug products are made available to patients. This would include results from any post marketing tests or vigilance required as a condition of approval. The manufacturer and manufacturing facilities we use to make any of our drug candidates will also be subject to periodic review and inspection by regulatory authorities, including the FDA. The discovery of any new or previously unknown problems with the product, manufacturer or facility may result in restrictions on the drug or manufacturer or facility, including withdrawal of the drug from the market. Our product promotion, advertising and labeling also will be subject to regulatory requirements and continuing regulatory review. If we fail to comply with applicable continuing regulatory requirements, we may be subject to fines, suspension or withdrawal of regulatory approval, product recalls and seizures, operating restrictions and other adverse consequences.

We are subject to extensive U.S. and foreign government regulation, including the requirement of approval before our products may be manufactured or marketed.

We, our present and future collaboration partners, and the drug product candidates developed by us or in collaboration with partners are subject to extensive regulation by governmental authorities in the U.S. and other countries. Failure to comply with applicable requirements could result in, among other things, any of the following actions: warning letters, fines and other civil penalties, unanticipated expenditures, delays in approving or refusal to approve a product candidate, product recall or seizure, interruption of manufacturing or clinical trials, operating restrictions, injunctions and criminal prosecution.

Our product candidates cannot be marketed in the U.S. without FDA approval or clearance, and they cannot be marketed in foreign countries without applicable regulatory approval. Neither the FDA nor any foreign regulatory authority has approved any of our product candidates. Our product candidates are in pre-clinical and early clinical development, and will have to be approved by the FDA or applicable foreign regulatory authorities before they can be marketed in the U.S. or abroad. Obtaining regulatory approval requires substantial time, effort, and financial resources, and may be subject to both expected and unforeseen delays, including, without limitation, citizen’s petitions or other filings with the FDA, and there can be no assurance that any approval will be granted on a timely basis, if at all, or that delays will be resolved favorably or in a timely manner. If our product candidates are not approved in a timely fashion, or are not approved at all, our business and financial condition may be adversely affected. We, our present and

future collaboration partners or the FDA may suspend or terminate human clinical trials at any time on various grounds, including a finding that the patients are being exposed to an unacceptable health risk.

In addition, both before and after regulatory approval, we, our collaboration partners and our product candidates are subject to numerous requirements by the FDA and foreign regulatory authorities covering, among other things, testing, manufacturing, quality control, labeling, advertising, promotion, distribution and export. These requirements may change and additional government regulations may be promulgated that could affect us, our collaboration partners or our product candidates. We cannot predict the likelihood, nature or extent of government regulation that may arise from future legislation or administrative action, either in the U.S. or abroad. There can be no assurance that we will not be required to incur significant costs to comply with such laws and regulations in the future or that such laws or regulations will not have a material adverse effect upon our business.

We use hazardous chemicals and biological materials in our business. Any disputes relating to improper use, handling, storage or disposal of these materials could be time-consuming and costly.

Our research and development operations involve the use of hazardous and biological, potentially infectious, materials. We are subject to the risk of accidental contamination or discharge or any resultant injury from these materials. Federal, state and local laws and regulations govern the use, manufacture, storage, handling and disposal of these materials and specific waste products. We could be subject to damages, fines or penalties in the event of an improper or unauthorized release of, or exposure of individuals to, these hazardous materials, and our liability could be substantial. The costs of complying with these current and future environmental laws and regulations may be significant, thereby impairing our business.

We are also subject to numerous environmental, health and workplace safety laws and regulations, including those governing laboratory procedures, exposure to blood-borne pathogens and the handling of biohazardous materials. We maintain workers’ compensation insurance to cover us for costs and expenses we may incur due to injuries to our employees resulting from the use of these materials. The limits of our workers’ compensation insurance are mandated by state law, and our workers’ compensation liability is capped at these state-mandated limits. We do not maintain insurance for environmental liability or toxic tort claims that may be asserted against us in connection with our storage or disposal of biological, hazardous or radioactive materials. Additional federal, state and local laws and regulations affecting our operations may be adopted in the future. We may incur substantial costs to comply with, and substantial fines or penalties if we violate, any of these laws or regulations.

Failure to comply with foreign regulatory requirements governing human clinical trials and marketing approval for drugs could prevent us from selling our drug candidates in foreign markets, which may adversely affect our operating results and financial condition.

The requirements governing the conduct of clinical trials, product licensing, pricing and reimbursement for marketing our drug candidates outside the U.S. vary greatly from country to country. We have limited experience in obtaining foreign regulatory approvals. The time required to obtain approvals outside the U.S. may differ from that required to obtain FDA approval. We may not obtain foreign regulatory approvals on a timely basis, if at all. Approval by the FDA does not ensure approval by regulatory authorities in other countries, and approval by one foreign regulatory authority does not ensure approval by regulatory authorities in other countries or by the FDA. Failure to comply with these regulatory requirements or obtain required approvals could impair our ability to develop foreign markets for our drug candidates and may have a material adverse effect on our financial condition or results of operations.

We may become dependent on our collaborative arrangements with third parties for a substantial portion of our revenue, and our development and commercialization activities may be delayed or reduced if we fail to initiate, negotiate or maintain successful collaborative arrangements.

We may become dependent on possible future collaborators to develop and commercialize many of our product candidates and to provide the regulatory compliance, sales, marketing and distribution capabilities required for the success of our business. If we fail to secure or maintain successful collaborative arrangements, our development and commercialization activities will be delayed, reduced or terminated, and our revenues could be materially and adversely impacted.

Over the next several years, we may depend on these types of collaboration partnerships for a significant portion of our revenue. The expected future milestone payments and cost reimbursements from collaboration agreements could provide an important source of financing for our research and development programs, thereby facilitating the application of our technology to the development and commercialization of our products. These collaborative agreements might be terminated either by us or by our partners upon the satisfaction of certain notice requirements. Our partners may not be precluded from independently pursuing competing products and drug delivery approaches or technologies. Even if our partners continue their contributions to our collaborative arrangements, of which there can be no assurance, they may nevertheless determine not to actively pursue the development or commercialization of any resulting products. Our partners may fail to perform their obligations under the collaborative arrangements or may be slow in performing their obligations. In addition, our partners may experience financial difficulties at any time that could prevent them from having available funds to contribute to these collaborations. If our collaboration partners fail to conduct their commercialization, regulatory compliance, sales and marketing or distribution activities successfully and in a timely manner, or if they terminate or materially modify their agreements with us, the development and commercialization of one or more product candidates could be delayed, curtailed or terminated because we may not have sufficient financial resources or capabilities to continue such development and commercialization on our own.

For example, in February 2011, we entered into an exclusive research and license agreement with Debiopharm S.A. concerning the development and commercialization of our pre-clinical program in bladder cancer, pursuant to which we and Debiopharm will work together to advance to market an RNAi-based therapy for the treatment of non-muscle invasive bladder cancer. Under the agreement, Debiopharm will have full responsibility for the development and commercialization of any products arising from the partnership, and will fund all of our research and development costs for the bladder cancer program beginning in February 2011. Debiopharm also agreed to pay to us up to $25 million based on predefined research and development milestones as well as royalties on the sales of products resulting from the partnership. If Debiopharn terminates this agreement or fails to perform its obligations thereunder, we may not be able to advance our bladder cancer program as scheduled, or at all. If that were to occur, we may not receive any revenues from our bladder cancer program or our agreement with Debiopharm, including any milestone or royalty payments.

An interruption in the supply of our raw and bulk materials needed for our product candidates could cause our product development to be slowed or stopped.

We currently obtain supplies of critical raw and bulk materials used in our research and development efforts from several suppliers. However, we do not have long-term contracts with any of these suppliers. While our existing arrangements supply sufficient quantities of raw and bulk materials needed to accomplish the current preclinical and clinical development of our product candidates, there can be no assurance that we would have the capability to manufacture sufficient quantities of our product candidates to meet our needs if our suppliers are unable or unwilling to supply such materials. Any delay or disruption in the availability of raw or bulk materials could slow or stop research and development of the relevant product.

We rely and anticipate that we will continue to rely on third parties to conduct our clinical trials, and those third parties may not perform satisfactorily, including failing to meet established deadlines for the completion of such clinical trials.

We are, and anticipate that we will continue to be, dependent on contract research organizations, third-party vendors and investigators for pre-clinical testing and clinical trials related to our drug discovery and development efforts. These parties are not our employees and we cannot control the amount or timing of

resources that they devote to our programs. If they fail to devote sufficient time and resources to our drug development programs or if their performance is substandard, it will delay the development and commercialization of our product candidates. The parties with which we contract for execution of our clinical trials play a significant role in the conduct of the trials and the subsequent collection and analysis of data. Their failure to meet their obligations could adversely affect clinical development of our product candidates. Moreover, these parties also may have relationships with other commercial entities, some of which may compete with us. If they assist our competitors, it could harm our competitive position.

If we were to lose our relationship with any one or more of these parties, we could experience a significant delay in both identifying another comparable provider and then contracting for its services. We may then be unable to retain an alternative provider on reasonable terms, if at all. Even if we locate an alternative provider, is it likely that this provider may need additional time to respond to our needs and may not provide the same type or level of service as the original provider. In addition, any provider that we retain will be subject to Good Laboratory Practices, or cGLP, and similar foreign standards and we do not have control over compliance with these regulations by these providers. Consequently, if these practices and standards are not adhered to by these providers, the development and commercialization of our product candidates could be delayed.

We have very limited experience in marketing, selling or distributing our products, and we may need to rely on marketing partners or contract sales companies.

Even if we are able to develop our products and obtain necessary regulatory approvals, we have very limited experience or capabilities in marketing , selling or distributing our products. We currently have no sales, marketing and distribution infrastructure. Accordingly, we will be dependent on our ability to build this capability ourselves, which would require the investment of significant financial and management resources, or to find collaborative marketing partners or contract sales companies for commercial sale of our internally-developed products. Even if we find a potential marketing partner, of which there can be no assurance, we may not be able to negotiate a licensing contract on favorable terms to justify our investment or achieve adequate revenues.

We have very limited manufacturing experience or resources and we must incur significant costs to develop this expertise or rely on third parties to manufacture our products.

We have very limited manufacturing experience. Our internal manufacturing capabilities are limited to small-scale production of non-cGMP material for use inin vitro andin vivo experiments. Some of our product candidates utilize specialized formulations whose scale-up and manufacturing could be very difficult. We also have very limited experience in such scale-up and manufacturing, requiring us to depend on a limited number of third parties, who might not be able to deliver in a timely manner, or at all. In order to develop products, apply for regulatory approvals and commercialize our products, we will need to develop, contract for, or otherwise arrange for the necessary manufacturing capabilities. We may manufacture clinical trial materials ourselves or we may rely on others to manufacture the materials we will require for any clinical trials that we initiate. There are a limited number of manufacturers that supply synthetic siRNAs. We currently rely on several contract manufacturers for our supply of synthetic siRNAs. There are risks inherent in pharmaceutical manufacturing that could affect the ability of our contract manufacturers to meet our delivery time requirements or provide adequate amounts of material to meet our needs. Included in these risks are synthesis and purification failures and contamination during the manufacturing process, which could result in unusable product and cause delays in our development process, as well as additional expense to us. To fulfill our siRNA requirements, we may also need to secure alternative suppliers of synthetic siRNAs. In addition to the manufacture of the synthetic siRNAs, we may have additional manufacturing requirements related to the technology required to deliver the siRNA to the relevant cell or tissue type. In some cases, the delivery technology we utilize is highly specialized or proprietary, and for technical and legal reasons, we may have access to only one or a limited number of potential manufacturers for such delivery technology. Failure by these manufacturers to properly formulate our siRNAs for delivery could also result in unusable product and cause delays in our discovery and development process, as well as additional expense to us.

The manufacturing process for any products that we may develop is subject to the FDA and foreign regulatory authority approval process and we will need to contract with manufacturers who can meet all applicable FDA and foreign regulatory authority requirements on an ongoing basis. In addition, if we receive the necessary regulatory approval for any product candidate, we also expect to rely on third parties, including our commercial collaborators, to produce materials required for commercial supply. We may experience difficulty in obtaining adequate manufacturing capacity for our needs. If we are unable to obtain or maintain contract manufacturing for these product candidates, or to do so on commercially reasonable terms, we may not be able to successfully develop and commercialize our products.

To the extent that we enter into manufacturing arrangements with third parties, we will depend on these third parties to perform their obligations in a timely manner and consistent with regulatory requirements, including those related to quality control and quality assurance. The failure of a third-party manufacturer to perform its obligations as expected could adversely affect our business in a number of ways, including:

we may not be able to initiate or continue pre-clinical and clinical trials of products that are under development;

we may be delayed in submitting regulatory applications, or receiving regulatory approvals, for our product candidates;

we may lose the cooperation of our collaborators;

our products could be the subject of inspections by regulatory authorities;

we may be required to cease distribution or recall some or all batches of our products; and

ultimately, we may not be able to meet commercial demands for our products.

If a third-party manufacturer with whom we contract fails to perform its obligations, we may be forced to manufacture the materials ourselves, for which we may not have the capabilities or resources, or enter into an agreement with a different third-party manufacturer, which we may not be able to do on reasonable terms, if at all. In some cases, the technical skills required to manufacture our product may be unique to the original manufacturer and we may have difficulty transferring such skills to a back-up or alternate supplier, or we may be unable to transfer such skills at all. In addition, if we are required to change manufacturers for any reason, we will be required to verify that the new manufacturer maintains facilities and procedures that comply with quality standards and with all applicable regulations and guidelines. The delays associated with the verification of a new manufacturer could negatively affect our ability to develop product candidates in a timely manner or within budget. Furthermore, a manufacturer may possess technology related to the manufacture of our product candidate that such manufacturer owns independently. This would increase our reliance on such manufacturer or require us to obtain a license from such manufacturer in order to have another third party manufacture our products.

If we are unable to adequately protect our proprietary technology from legal challenges, infringement or alternative technologies, our competitive position may be hurt and our operating results may be negatively impacted.

We specialize in the development and delivery of therapeutics based on RNA-based technologies, and rely on the issuance of patents, both in the U.S. and internationally, for protection against competitive technologies. Although we believe we exercise the necessary due diligence in our patent filings, our proprietary position is not established until the appropriate regulatory authorities actually issue a patent, which may take several years from initial filing or may never occur.

Moreover, even the established patent positions of pharmaceutical companies are generally uncertain and involve complex legal and factual issues. Although we believe our issued patents are valid, third parties may infringe our patents or may initiate proceedings challenging the validity or enforceability of our patents. The issuance of a patent is not conclusive as to its claim scope, validity or enforceability. Challenges raised in patent infringement litigation we initiate or in proceedings initiated by third parties may result in determinations that our patents have not been infringed or that they are invalid, unenforceable or otherwise subject to limitations. In the event of any such determinations, third parties may be able to use the discoveries or technologies claimed in our patents without paying us licensing fees or royalties, which could significantly diminish the value of these discoveries or technologies. As a result of such determinations, we may be enjoined from pursuing research, development or commercialization of potential products or may be required to obtain licenses, if available, to the third party patents or to develop or obtain alternative technology. Responding to challenges initiated by third parties may require significant expenditures and divert the attention of our management and key personnel from other business concerns.

Furthermore, it is possible others will infringe or otherwise circumvent our issued patents and that we will be unable to fund the cost of litigation against them or that we would elect not to pursue litigation. In addition, enforcing our patents against third parties may require significant expenditures regardless of the outcome of such efforts. We also cannot assure you that others have not filed patent applications for technology covered by our pending applications or that we were the first to invent the technology. There may also exist third party patents or patent applications relevant to our potential products that may block or compete with the technologies covered by our patent applications and third parties may independently develop IP similar to our patented IP, which could result in, among other things, interference proceedings in the U.S. Patent and Trademark Office to determine priority of invention.

In addition, we may not be able to protect our established and pending patent positions from competitive technologies, which may provide more effective therapeutic benefit to patients and which may therefore make our products, technology and proprietary position obsolete.

We also rely on copyright and trademark protection, trade secrets, know-how, continuing technological innovation and licensing opportunities. In an effort to maintain the confidentiality and ownership of our trade secrets and proprietary information, we require our employees, consultants, advisors and others to whom we disclose confidential information to execute confidentiality and proprietary information agreements. However, it is possible that these agreements may be breached, invalidated or rendered unenforceable, and if so, there may not be an adequate corrective remedy available. Furthermore, like many companies in our industry, we may from time to time hire scientific personnel formerly employed by other companies involved in one or more areas similar to the activities we conduct. In some situations, our confidentiality and proprietary information agreements may conflict with, or be subject to, the rights of third parties with whom our employees, consultants or advisors have prior employment or consulting relationships. Although we require our employees and consultants to maintain the confidentiality of all confidential information of previous employers, we or these individuals may be subject to allegations of trade secret misappropriation or other similar claims as a result of their prior affiliations. Finally, others may independently develop substantially equivalent proprietary information and techniques, or otherwise gain access to our trade secrets. Our failure to protect our proprietary information and techniques may inhibit or limit our ability to exclude certain competitors from the market and execute our business strategies.

If we are unable to adequately protect our proprietary intellectual property from legal challenges, infringement or alternative technologies, we will not be able to compete effectively in the drug discovery and development business.

Because intellectual property rights are of limited duration, expiration of intellectual property rights and licenses will negatively impact our operating results.

Intellectual property rights, such as patents and license agreements based on those patents, generally are of limited duration. Our operating results depend on our patents and IP licenses. Therefore, the expiration or other loss of rights associated with IP and IP licenses can negatively impact our business.

Our patent applications may be inadequate in terms of priority, scope or commercial value.

We apply for patents covering our discoveries and technologies as we deem appropriate. However, we may fail to apply for patents on important discoveries or technologies in a timely fashion or at all. Also, our pending patent applications may not result in the issuance of any patents. These applications may not be sufficient to meet the statutory requirements for patentability, and therefore we may be unable to obtain enforceable patents covering the related discoveries or technologies we may want to commercialize. In addition, because patent applications are maintained in secrecy for approximately 18 months after filing, other parties may have filed patent applications relating to inventions before our applications covering the same or similar inventions. In addition, foreign patent applications are often published initially in local languages, and until an English language translation is available it can be impossible to determine the significance of a third party invention. Any patent applications filed by third parties may prevail over our patent applications or may result in patents that issue alongside patents issued to us, leading to uncertainty over the scope of the patents or the freedom to practice the claimed inventions.

Although we have in-licensed a number of issued patents, the discoveries or technologies covered by these patents may not have any therapeutic or commercial value. Also, issued patents may not provide commercially meaningful protection against competitors. Other parties may be able to design around our issued patents or independently develop products having effects similar or identical to our patented product candidates. In addition, the scope of our patents is subject to considerable uncertainty and competitors or other parties may obtain similar patents of uncertain scope.

We are dependent on technologies we license, and if we lose the right to license such technologies or we fail to license new technologies in the future, our ability to develop new products would be harmed.

We currently are dependent on licenses from third parties for our key technologies relating to fundamental RNAi technologies. Our current licenses impose, and any future licenses we enter are likely to impose, various development, funding, royalty, diligence, sublicensing, insurance and other obligations on us. If our license with respect to any of these technologies is terminated for any reason, the development of the products contemplated by the licenses would be delayed, or suspended altogether, while we seek to license similar technology or develop new non-infringing technology. The costs of obtaining new licenses are high, and many patents in the RNAi field have already been exclusively licensed to third parties, including our competitors. If any of our existing licenses is terminated, the development of the products contemplated by the licenses could be delayed or terminated and we may not be able to negotiate additional licenses on acceptable terms, if at all, which would have a material adverse effect on our business.

We may be required to defend lawsuits or pay damages for product liability claims.

Our business inherently exposes us to potential product liability claims. We face substantial product liability exposure in human clinical trials that we may initiate and for products that we sell, or manufacture for others to sell, after regulatory approval. The risk exists even with respect to those drugs that are approved by regulatory agencies for commercial distribution and sale and are manufactured in facilities licensed and regulated by regulatory agencies. Any product liability claims, regardless of their merits, could be costly, divert management’s attention, delay or prevent completion of our clinical development programs, and adversely affect our reputation and the demand for our products. We currently have product liability insurance that we believe is appropriate for our stage of development and may need to obtain higher levels prior to marketing any of our product candidates. Any insurance we have or may obtain may not provide sufficient coverage against potential liabilities. Furthermore, clinical trial and product liability insurance is becoming increasingly expensive. As a result, we may be unable to obtain sufficient insurance at a reasonable cost to protect us against losses caused by product liability claims that could have a material adverse effect on our business.

Our future results of operations depend, to a significant degree, upon our and any collaboration partners’ ability to successfully develop and commercialize pharmaceutical products. The development and commercialization process, particularly with respect to innovative products, is both time consuming and costly and involves a high degree of business risk. Successful product development in the pharmaceutical industry is highly uncertain, and very few research and development projects result in a commercial product. Product candidates that appear promising in the early phases of development, such as in preclinical testing or in early human clinical trials, may fail to reach the market for a number of reasons, such as:

a product candidate may not perform as expected in later or broader trials in humans and limit marketability of such product candidate;

necessary regulatory approvals may not be obtained in a timely manner, if at all;

a product candidate may not be able to be successfully and profitably produced and marketed;

third parties may have proprietary rights to a product candidate, and do not allow sale on reasonable terms; or

a product candidate may not be financially successful because of existing therapeutics that offer equivalent or better treatments.

Only one of our product candidates utilizing our technologies has commenced human clinical studies, and none of such product candidates has been approved by the FDA or any foreign regulatory authority. There can be no assurance that any of our product candidates currently in research or development, or that may enter research or development, will ever be successfully commercialized, and delays in any part of the process or our inability to obtain regulatory approval could adversely affect our operating results by restricting introduction of new products by us or any future collaboration partners.

Even if we are successful in developing and commercializing a product candidate, it is possible that the commercial opportunity for RNA-based therapeutics will be limited.

The product candidates that we are developing are based on new technologies and therapeutic approaches, none of which have yet been brought to market. Key participants in pharmaceutical marketplaces, such as physicians, third-party payors and consumers, may not accept a product intended to improve therapeutic results based on RNAi technology. Accordingly, while we believe there will be a commercial market for RNA-based therapeutics utilizing our technologies, there can be no assurance that this will be the case, in particular given the novelty of the field. Many factors may affect the market acceptance and commercial success of any potential products, including:

establishment and demonstration of the effectiveness and safety of the drugs;

timing of market entry as compared to competitive products and alternative treatments;

the benefits of our drugs relative to their prices, and the comparative price of competing products and treatments;

the availability of adequate government and third-party payor reimbursement;

marketing and distribution support of our products;

the safety, efficacy and ease of administration of our product candidates;

the willingness of patients to accept, and the willingness of medical professionals to prescribe, relatively new therapies; and

any restrictions on labeled indications.

Any drugs we develop may become subject to unfavorable pricing regulations, third-party reimbursement practices or healthcare reform initiatives, which could have a material adverse effect on our business.

The success of our products will depend upon the extent to which third-party payors, such as Medicare, Medicaid and other domestic and international government programs, private insurance plans and managed care programs, provide reimbursement for the use of such products. Most third-party payors may deny reimbursement if they determine that a medical product was not used in accordance with cost-effective treatment methods, as determined by the third-party payor, or was used for an unapproved indication.

Third-party payors also may refuse to reimburse for experimental procedures and devices. Furthermore, because our programs are in the early stages of development, we are unable at this time to determine their cost-effectiveness and the level or method of reimbursement. Increasingly, the third-party payors, who reimburse patients, such as government and private insurance plans, are requiring that drug companies provide them with predetermined discounts from list prices, and are challenging the prices charged for medical products. If the price we are able to charge for any products we develop is inadequate in light of our development and other costs, our profitability could be adversely effected.

We currently expect that any drugs we develop may need to be administered under the supervision of a physician. Under currently applicable law, drugs that are not usually self-administered may be eligible for coverage by the Medicare program if:

they are “incidental” to a physician’s services;

they are “reasonable and necessary” for the diagnosis or treatment of the illness or injury for which they are administered according to accepted standards of medical practice;

they are not excluded as immunizations; and

they have been approved by the FDA.

There may be significant delays in obtaining insurance coverage for newly-approved drugs, and insurance coverage may be more limited than the purpose for which the drug is approved by the FDA. Moreover, eligibility for insurance coverage does not imply that any drug will be reimbursed in all cases or at a rate that covers our costs, including research, development, manufacture, sale and distribution. Interim payments for new drugs, if applicable, may also not be sufficient to cover our costs and may not be made permanent. Reimbursement may be based on payments for other services and may reflect budgetary constraints or imperfections in Medicare data. Net prices for drugs may be reduced by mandatory discounts or rebates required by government health care programs or private payors and by any future relaxation of laws that presently restrict imports of drugs from countries where they may be sold at lower prices than in the United States. Third-party payors often rely upon Medicare coverage policy and payment limitations in setting their own reimbursement rates. Our inability to promptly obtain coverage and profitable reimbursement rates from both government-funded and private payors for new drugs that we develop could have a material adverse effect on our operating results, our ability to raise capital needed to develop products, and our overall financial condition.

We believe that the efforts of governments and third-party payors to contain or reduce the cost of healthcare and legislative and regulatory proposals to broaden the availability of healthcare will continue to affect the business and financial condition of pharmaceutical and biopharmaceutical companies. A number of legislative and regulatory changes in the healthcare system in the United States and other major healthcare markets have been proposed in recent years, and such efforts have expanded substantially in

recent years. These developments have included prescription drug benefit legislation that was enacted and took effect in January 2006, healthcare reform legislation recently enacted by certain states, and major healthcare reform legislation that was passed by Congress and enacted into law in the United States in 2010. These developments could, directly or indirectly, affect our ability to sell our products, if approved, at a favorable price.

In particular, in March 2010, the Patient Protection and Affordable Care Act, or PPACA, and a related reconciliation bill were signed into law. This new legislation changes the current system of healthcare insurance and benefits intended to broaden coverage and control costs. The new law also contains provisions that will affect companies in the pharmaceutical industry and other healthcare related industries by imposing additional costs and changes to business practices.

The full effects of the U.S. healthcare reform legislation cannot be known until the new law is implemented through regulations or guidance issued by the Centers for Medicare & Medicaid Services and other federal and state healthcare agencies. The financial impact of the U.S. healthcare reform legislation over the next few years will depend on a number of factors, including but not limited, to the policies reflected in implementing regulations and guidance, and changes in sales volumes for products affected by the new system of rebates, discounts and fees. The new legislation may also have a positive impact on our future net sales, if any, by increasing the aggregate number of persons with healthcare coverage in the United States, but such increases are unlikely to be realized until approximately 2014 at the earliest.

Moreover, we cannot predict what healthcare reform initiatives may be adopted in the future. Further federal and state legislative and regulatory developments are likely, and we expect ongoing initiatives in the United States to increase pressure on drug pricing. Such reforms could have an adverse effect on anticipated revenues from product candidates that we may successfully develop and for which we may obtain regulatory approval and may affect our overall financial condition and ability to develop drug candidates.

The pharmaceutical market is intensely competitive. If we are unable to compete effectively with existing drugs, new treatment methods and new technologies, we may be unable to commercialize successfully any drugs that we develop.

The pharmaceutical market is intensely competitive and rapidly changing. Many large pharmaceutical and biotechnology companies, academic institutions, governmental agencies and other public and private research organizations are pursuing the development of novel drugs for the same diseases that we are targeting or expect to target. Many of our competitors have:

much greater financial, technical and human resources than we have at every stage of the discovery, development, manufacture and commercialization of products;

more extensive experience in pre-clinical testing, conducting clinical trials, obtaining regulatory approvals, and in manufacturing, marketing and selling pharmaceutical products;

product candidates that are based on previously tested or accepted technologies;

products that have been approved or are in late stages of development; and

collaborative arrangements in our target markets with leading companies and research institutions.

We will face intense competition from drugs that have already been approved and accepted by the medical community for the treatment of the conditions for which we may develop drugs. We also expect to face competition from new drugs that enter the market. We believe a significant number of drugs are currently under development, and may become commercially available in the future, for the treatment of conditions for which we may try to develop drugs. These drugs may be more effective, safer, less expensive, or marketed and sold more effectively, than any products we develop.

If we successfully develop product candidates, and obtain approval for them, we will face competition based on many different factors, including:

the safety and effectiveness of our products;

the ease with which our products can be administered and the extent to which patients accept relatively new routes of administration;

the timing and scope of regulatory approvals for these products;

the availability and cost of manufacturing, marketing and sales capabilities;

reimbursement coverage; and

Our competitors may develop or commercialize products with significant advantages over any products we develop based on any of the factors listed above or on other factors. Our competitors may therefore be more successful in commercializing their products than we are, which could adversely affect our competitive position and business. Competitive products may make any products we develop obsolete or noncompetitive before we can recover the expenses of developing and commercializing our product candidates. Such competitors could also recruit our employees, which could negatively impact our level of expertise and the ability to execute on our business plan. Furthermore, we also face competition from

existing and new treatment methods that reduce or eliminate the need for drugs, such as the use of advanced medical devices. The development of new medical devices or other treatment methods for the diseases we are targeting could make our product candidates noncompetitive, obsolete or uneconomical.

We may be unable to compete successfully against other companies that are working to develop novel drugs and technology platforms using technology similar to ours.

In addition to the competition we face from competing drugs in general, we also face competition from other pharmaceutical companies and medical institutions that are working to develop novel drugs using technology that competes more directly with our own. Among those companies that are working in this field are: Alnylam Pharmaceuticals, Benitec, Dicerna Pharmaceuticals, Inc., Quark Pharmaceuticals, Inc., Regulus, RXi Pharmaceuticals, Silence Therapeutics plc and Tekmira Pharmaceutical Corp., as well as a number of the multinational pharmaceutical companies. Any of these companies may develop its technology more rapidly and more effectively than us.

In addition to competition with respect to our technology and with respect to specific products, we face substantial competition to discover and develop safe and effective means to deliver the drugs that we develop to the relevant cell and tissue types. Substantial resources are being expended by third parties, both in academic laboratories and in the corporate sector, in the effort to discover and develop a safe and effective means of delivery into the relevant cell and tissue types. If safe and effective means of delivery to the relevant cell and tissue types were developed by our competitors, our ability to successfully commercialize a competitive product would be adversely affected.

Many of our competitors have substantially greater research and development capabilities and financial, scientific, technical, manufacturing, marketing, distribution, and other resources than us. Even if we are successful in developing our product candidates, in order to compete successfully we may need to be first to market or to demonstrate that our products are superior to therapies based on different technologies. If we are not first to market or are unable to demonstrate such superiority, any products for which we are able to obtain approval may not be successful.

The trading price of our common stock has been volatile, and investors in our common stock may experience substantial losses.

The trading price of our common stock has been volatile and may become volatile again in the future. The trading price of our common stock could decline or fluctuate in response to a variety of factors, including:

our ability to enter into collaborative arrangements with third parties;

our failure to meet the performance estimates of securities analysts;

changes in buy/sell recommendations by securities analysts;

negative results from our clinical and pre-clinical trials;

fluctuation in our quarterly operating results;

substantial sales of our common stock;

general stock market conditions;

our general financial condition; or

other economic or external factors.

The stock markets in general, and the markets for biotechnology stocks in particular, have experienced extreme volatility that has often been unrelated to the operating performance of particular companies. These broad market fluctuations may adversely affect the trading price of our common stock.

The Nasdaq Global Market imposes listing standards on our common stock that we may not be able to fulfill, thereby leading to a possible delisting of our common stock.

As a listed Nasdaq Global Market company, we are subject to rules covering, among other things, certain major corporate transactions, the composition of our Board of Directors and committees thereof, minimum bid price of our common stock and minimum stockholders equity. The failure to meet these or other Nasdaq Global Market requirements may result in the de-listing of our common stock from the Nasdaq Global Market, which could adversely affect the liquidity and market price thereof.

Various restrictions in our charter documents and Delaware law could prevent or delay a change in control of us that is not supported by our board of directors.

We are subject to a number of provisions in our charter documents and Delaware law that may discourage, delay or prevent a merger, acquisition or change of control that a stockholder may consider favorable. These anti-takeover provisions include:

advance notice procedures for nominations of candidates for election as directors and for stockholder proposals to be considered at stockholders’ meetings; and

the Delaware anti-takeover statute contained in Section 203 of the Delaware General Corporation Law.

Section 203 of the Delaware General Corporation Law prohibits a merger, consolidation, asset sale or other similar business combination between us and any stockholder of 15% or more of our voting stock for a period of three years after the stockholder acquires 15% or more of our voting stock, unless (1) the transaction is approved by our board of directors before the stockholder acquires 15% or more of our voting stock, (2) upon completing the transaction the stockholder owns at least 85% of our voting stock outstanding at the commencement of the transaction, or (3) the transaction is approved by our board of directors and the holders of 66 2/3% of our voting stock, excluding shares of our voting stock owned by the stockholder.

We have never paid dividends on our common stock and we do not anticipate paying cash dividends in the foreseeable future.

We have not paid any dividends on our common stock to date, and we currently intend to retain our future earnings, if any, to fund the development and growth of our business. In addition, the terms of any future debt or credit facility may preclude us from paying any dividends.

The anti-takeover provisions of our stockholder rights plan may entrench management, may delay or prevent beneficial takeover bids by third parties and may prevent or frustrate any stockholder attempt to replace or remove the current management even if the stockholders consider it beneficial to do so.

We have a stockholder rights plan designed to protect our stockholders from coercive or unfair takeover tactics. Under the plan, we declared a dividend of one preferred stock purchase right for each share of common stock outstanding on March 17, 2000. Each preferred stock purchase right entitles the holder to purchase from us 1/1000th of a share of Series A Junior Participating Preferred Stock for $50.00. In the event any acquiring entity or group accumulates or initiates a tender offer to purchase 15% or more of our common stock, then each holder of a preferred stock purchase right, other than the acquiring entity and its affiliates, will have the right to receive, upon exercise of the preferred stock purchase right, shares

of our common stock or shares in the acquiring entity having a value equal to two times the exercise price of the preferred stock purchase right. The preferred stock purchase rights will expire on March 17, 2013, unless we extend the expiration date or in certain limited circumstances, we redeem or exchange such rights prior to such date.

The intent of the stockholder rights plan is to protect our stockholders’ interests by encouraging anyone seeking control of our company to negotiate with our board of directors. However, our stockholder rights plan could make it more difficult for a third party to acquire us without the consent of our board of directors, even if doing so may be beneficial to our stockholders. This plan may discourage, delay or prevent a tender offer or takeover attempt, including offers or attempts that could result in a premium over the market price of our common stock. This plan could reduce the price that investors might be willing to pay for shares of our common stock in the future. Furthermore, the anti-takeover provisions of our stockholder rights plan may entrench management and make it more difficult for stockholders to replace management even if the stockholders consider it beneficial to do so.

A significant number of shares of our common stock are subject to options, warrants and subscription investment units, and we expect to sell additional shares of our common stock in the future. Sales of these shares will dilute the interests of other security holders and may depress the price of our common stock.

As of March 15, 2011, there were 34,364,514 shares of common stock outstanding. As of March 15, 2011, there were vested outstanding options to purchase 2,033,428 shares of common stock, unvested outstanding options to purchase 543,633 shares of common stock, outstanding warrants to purchase 4,943,276 shares of common stock, and outstanding subscription investment units to purchase 2,348,550 shares of common stock. At March 15, 2011, there were 1,077,895 shares of common stock available for future issuance under our stock compensation plans. In addition, we may issue additional common stock and warrants from time to time to finance our operations. We may also issue additional shares to fund potential acquisitions or in connection with additional stock options or restricted stock granted to our employees, officers, directors and consultants under our equity compensation plans. The issuance, perception that issuance may occur, or exercise of warrants or options will have a dilutive impact on other stockholders and could have a material negative effect on the market price of our common stock.

We will not receive any of the proceeds from the sale of shares of our common stock in this offering. The selling stockholders will receive all of the proceeds from this offering.

The selling stockholders will pay any underwriting discounts and commissions and expenses incurred by the selling stockholders for brokerage, accounting, tax or legal services or any other expenses incurred by the selling stockholders in disposing of the shares. We will bear all other costs, fees and expenses incurred in effecting the registration of the shares covered by this prospectus, including, without limitation, all registration and filing fees, and fees and expenses of our counsel and our independent registered public accountants.

Set forth below is a description of our capital stock. The following description of our capital stock is a summary and is subject to and qualified by the applicable provisions of our certificate of incorporation, our bylaws and the relevant provisions of the laws of the State of Delaware.

We are currently authorized to issue up to 90,000,000 shares of common stock, par value $.006 per share. As of March 15, 2011, 34,364,514 shares of our common stock were issued and outstanding,

3,654,956 unissued shares of common stock were reserved for future issuance under our equity compensation plans, 4,943,276 unissued shares of common stock were reserved for issuance upon the exercise of outstanding warrants, and 2,348,550 unissued shares of common stock were reserved for issuance upon the exercise of outstanding subscription investment units, leaving approximately 44,688,704 shares of common stock unissued and unreserved.

All shares of common stock issued will be duly authorized, fully paid and non-assessable. The holders of our common stock are entitled to one vote for each share held of record on all matters submitted to a vote of the holders of our common stock. Under Delaware law, stockholders generally are not liable for our debts or obligations. Our certificate of incorporation does not authorize cumulative voting for the election of directors. Subject to the rights of the holders of any class of our capital stock having any preference or priority over our common stock, the holders of shares of our common stock are entitled to receive dividends that are declared by the board of directors out of legally available funds. In the event of our liquidation, dissolution or winding-up, the holders of common stock are entitled to share ratably in our net assets remaining after payment of liabilities, subject to prior rights of preferred stock, if any, then outstanding. Our common stock has no preemptive rights, conversion rights, redemption rights or sinking fund provisions, and there are no dividends in arrears or default. All shares of our common stock have equal distribution, liquidation and voting rights, and have no preferences or exchange rights.

On February 22, 2000, our board of directors adopted a stockholder rights plan and declared a dividend of one preferred share purchase right for each outstanding share of common stock. Each right entitles the holder, once the right becomes exercisable, to purchase from us one one-thousandth of a share of our Series A Junior Participating Preferred Stock, par value $.01 per share. We issued these rights on March 17, 2000 to each stockholder of record on such date, and these rights attach to shares of common stock subsequently issued. The rights will cause substantial dilution to a person or group that attempts to acquire us on terms not approved by our board of directors and could, therefore, have the effect of delaying or preventing someone from taking control of us, even if a change of control were in the best interest of our stockholders.

Holders of our preferred share purchase rights are generally entitled to purchase from us one one-thousandth of a share of Series A preferred stock at a price of $50.00, subject to adjustment as provided in the Stockholder Rights Agreement. These preferred share purchase rights will generally be exercisable only if a person or group becomes the beneficial owner of 15 percent or more of our outstanding common stock or announces a tender offer for 15 percent or more of our outstanding common stock. Each holder of a preferred share purchase right, excluding an acquiring entity or any of its affiliates, will have the right to receive, upon exercise, shares of our common stock, or shares of stock of the acquiring entity, having a market value equal to two times the purchase price paid for one one-thousandth of a share of Series A preferred stock. The preferred share purchase rights expire on March 17, 2013, unless we extend the expiration date or in certain limited circumstances, we redeem or exchange such rights prior to such date.

We are authorized to issue 100,000 shares of preferred stock, par value $.01 per share, with 10,000 shares undesignated and 90,000 shares of previously undesignated preferred stock designated as Series A Junior Participating Preferred Stock.

We may issue shares of our authorized but unissued preferred stock in one or more series having the rights, privileges, and limitations, including voting rights, conversion rights, liquidation preferences, dividend rights and redemption rights, as may, from time to time, be determined by our board of directors. Preferred stock may be issued in the future in connection with acquisitions, financings, or other matters, as our board of directors deems appropriate. In the event that we determine to issue any shares of our authorized but unissued preferred stock, a certificate of designation containing the rights, privileges and limitations of this series of preferred stock will be filed with the Secretary of State of the State of Delaware. The effect of this preferred stock designation power is that our board of directors alone, subject to Federal securities laws, applicable blue sky laws, and Delaware law, may be able to authorize the issuance of

preferred stock which could have the effect of delaying, deferring, or preventing a change in control without further action by our stockholders, and may adversely affect the voting and other rights of the holders of our common stock.

As further inducement for BMR-3450 Monte Villa Parkway LLC (the “Landlord”), the successor-in-interest to Phase 3 Science Center LLC, to enter into a fifth amendment, dated as of December 16, 2010, of that certain Lease dated as of April 23, 2002 whereby we lease certain premises from the Landlord at 3450 Monte Villa Parkway in Bothell, Washington, we entered into a Stock Purchase Agreement (the “Purchase Agreement”) with BioMed Realty, L.P. (“BioMed”), the sole member of the Landlord, pursuant to which we agreed to issue to BioMed an aggregate of 2,115,727 shares (the “BioMed Shares”) of our common stock. The Purchase Agreement provides BioMed with certain piggyback registration rights with respect to the BioMed Shares, which rights continue until such time as the BioMed Shares may be sold publicly without restriction under the Securities Act, including in reliance on Rule 144 promulgated thereunder. The piggyback registration rights with respect to the BioMed Shares have been triggered as a result of the filing of the registration statement of which this prospectus forms a part.

Pursuant to that certain Payment Acknowledgement between our company and Canaccord Genuity Inc. (“Canaccord”) dated December 31, 2010, we issued to Canaccord an aggregate of 289,436 shares of our common stock (the “Canaccord Shares”) in full and complete satisfaction of any and all remaining liabilities owed to Canaccord by us arising out of that certain letter agreement dated February 4, 2010 between our company and Canaccord (the “Letter Agreement”). The services that Canaccord provided to us pursuant to the Letter Agreement related to that certain merger between a wholly-owned subsidiary of our company and Cequent Pharmaceuticals, Inc., which merger was consummated on July 21, 2010. In the Payment Acknowledgement, we agreed to use best efforts to file a registration statement registering the Canaccord Shares for resale under the Securities Act within thirty (30) days from the date of the Payment Acknowledgement and to cause such registration statement to be declared effective by the SEC as soon as practical thereafter.

Pursuant to Amendment No. 4 (“Amendment No. 4”), dated as of March 3, 2011, to that certain Patent Assignment and License Agreement effective as of May 21, 2008 by and between our company and Ribotask ApS, a privately-held Danish company, we agreed to issue to Ribotask such number of shares of our common stock having a total value equal to $80,000, with the value of each share to be determined based upon the volume weighted average price of our common stock on The Nasdaq Global Market for the five (5) trading days immediately prior to the effective date of Amendment No. 4. We also agreed to use reasonable best efforts to file a registration statement under the Securities Act to register the shares issued to Ribotask for resale within thirty (30) days from the effective date of Amendment No. 4 and to cause such registration statement to be declared effective by the SEC as soon as practicable thereafter. Based upon a volume weighted average price per share of $0.7032, we issued 113,766 shares of common stock to Ribotask in connection with Amendment No. 4, which shares are being registered on the registration statement of which this prospectus forms a part.

We are subject to Section 203 of the General Corporation Law of the State of Delaware. This law prohibits a publicly held Delaware corporation from engaging in any business combination with any interested stockholder for a period of three years following the date that the stockholder became an interested stockholder unless:

prior to the date of the transaction, the board of directors of the corporation approved either the business combination or the transaction which resulted in the stockholder becoming an interested stockholder;

upon consummation of the transaction which resulted in the stockholder becoming an interested stockholder, the interested stockholder owned at least 85% of the voting stock of the corporation outstanding at the time the transaction commenced, excluding for purposes of determining the number of shares outstanding those shares owned by persons who are directors and also officers and by employee stock plans in which employee participants do not have the right to determine confidentially whether shares held subject to the plan will be tendered in a tender or exchange offer; or

on or subsequent to the date of the transaction, the business combination is approved by the board of directors and authorized at an annual or special meeting of stockholders, and not by written consent, by the affirmative vote of at least two-thirds of the outstanding voting stock which is not owned by the interested stockholder.

Any merger or consolidation involving the corporation and the interested stockholder;

Any sale, transfer, pledge or other disposition of 10% or more of our assets involving the interested stockholder;

In general, any transaction that results in the issuance or transfer by a corporation of any of its stock to the interested stockholder; or

The receipt by the interested stockholder of the benefit of any loans, advances, guarantees, pledges or other financial benefits provided by or through the corporation.

In general, Section 203 defines an “interested stockholder” as an entity or person beneficially owning 15% or more of the outstanding voting stock of the corporation and any entity or person affiliated with or controlling or controlled by the entity or person.

Our common stock currently is trading on The NASDAQ Global Market under the symbol “MRNA.”.

American Stock Transfer & Trust Company is the transfer agent and registrar for our common stock.

Pursuant to that certain Payment Acknowledgement between our company and Canaccord Genuity Inc. (“Canaccord”) dated December 31, 2010, we issued to Canaccord an aggregate of 289,436 shares of our common stock (the “Canaccord Shares”) in full and complete satisfaction of any and all remaining liabilities owed to Canaccord by us arising out of that certain letter agreement dated February 4, 2010 between our company and Canaccord (the “Letter Agreement”). The services that Canaccord provided to us pursuant to the Letter Agreement related to that certain merger between a wholly-owned subsidiary of our company an Cequent Pharmaceuticals, Inc., which merger was consummated on July 21, 2010. In the Payment Acknowledgement, we agreed to use best efforts to file a registration statement registering the Canaccord Shares for resale under the Securities Act within thirty (30) days from the date of the Payment Acknowledgement and to cause such registration statement to be declared effective by the SEC as soon as practical thereafter.

Canaccord previously acted as placement agent for the placement of 1,346,389 shares of our common stock and warrants to purchase 875,155 shares of our common stock pursuant to that certain Placement Agency Agreement dated as of January 13, 2010 between our company and Canaccord, and as placement agent for the placement of 1,312,500 shares of our common stock and warrants to purchase 1,312,500 shares of our common stock pursuant to that certain Placement Agency Agreement dated as of June 9, 2009 between our company and Canaccord.

Pursuant to Amendment No. 4 (“Amendment No. 4”), dated as of March 3, 2011, to that certain Patent Assignment and License Agreement effective as of May 21, 2008 by and between our company and Ribotask ApS, a privately-held Danish company, we agreed to issue to Ribotask such number of shares of our common stock having a total value equal to $80,000, with the value of each share to be determined based upon the volume weighted average price of our common stock on The Nasdaq Global Market for the five (5) trading days immediately prior to the effective date of Amendment No. 4. We also agreed to use reasonable best efforts to file a registration statement under the Securities Act to register the shares issued to Ribotask for resale within thirty (30) days from the effective date of Amendment No. 4 and to cause such registration statement to be declared effective by the SEC as soon as practicable thereafter. Based upon a volume weighted average price per share of $0.7032, we issued 113,766 shares of common stock to Ribotask in connection with Amendment No. 4. Pursuant to our Patent Assignment and License Agreement with Ribotask, as amended from time to time, we had acquired from Ribotask exclusive rights for the development and commercialization of therapeutics incorporating Unlocked Nucleobase Analogs (UNA) and UNA-based diagnostics.

This prospectus covers the sale or other disposition by BioMed, Canaccord, Ribotask or their transferees of that number of shares of common stock set forth below. Throughout this prospectus, when we refer to the shares of our common stock being registered on behalf of the selling stockholders, we are referring to that number of shares of common stock set forth below that was issued to BioMed pursuant to the Purchase Agreement to Canaccord pursuant to the Payment Acknowledgement and to Ribotask pursuant to Amendment No. 4, and when we refer to the selling stockholders in this prospectus, we are referring to BioMed, Canaccord and Ribotask.

We are registering the shares specified below to permit the selling stockholders and their pledgees, donees, transferees or other successors-in-interest that receive their shares after the date of this prospectus to resell or otherwise dispose of the shares in the manner contemplated under the “Plan of Distribution.”

Except as otherwise disclosed in this “Selling Stockholders” section, or disclosed in the footnotes below, the selling stockholders do not have, or within the past three years have not had, any position, office or other material relationship with us or any of our affiliates.

We are registering for resale an aggregate of 2,518,929 shares of our common stock that we issued to the selling stockholders, as further described in this prospectus.

The following table sets forth the name of each selling stockholder, the number of shares owned by each selling stockholder, the number of shares that may be offered under this prospectus and the number of

shares of our common stock owned by each selling stockholder assuming all of the shares covered hereby are sold. Unless otherwise noted, the number of shares in the column “Number of Shares Being Offered” represents all of the shares that a selling stockholder may offer under this prospectus. Each selling stockholders may sell some, all or none of its shares. Other than as set forth below, we do not know how long the selling stockholders will hold the shares before selling them, and we currently have no agreements, arrangements or understandings with the selling stockholders regarding the sale or other disposition of any of the shares. The shares covered hereby may be offered from time to time by the selling stockholders.

The information set forth below is based upon information obtained from the selling stockholders and upon information in our possession regarding the issuance of shares of common stock to the selling stockholders. The percentages of shares owned after the offering are based on 34,364,514 shares of our common stock outstanding as of March 15, 2011, including the shares of common stock covered hereby.

The selling stockholders, and any of their pledgees, assignees and successors-in-interest (the “Selling Stockholders”), may from time to time offer and sell, separately or together, some or all of the shares of common stock covered by this registration statement. Registration of shares of common stock covered by the registration statement does not mean, however, that those shares necessarily will be offered or sold.

We will not receive any proceeds from the sale of the common stock by the Selling Stockholders.

The Selling Stockholders may sell shares in one or more of the following ways (or in any combination) from time to time:

through underwriters or dealers;

directly to one or more purchasers;

through any other methods described in a prospectus supplement.

Neither we nor the Selling Stockholders have entered into any agreements, understandings or arrangements with any underwriters or dealers regarding the sale of shares covered by the registration statement. At any time a particular offer of the shares covered by the registration statement is made, a revised prospectus or prospectus supplement, if required, will be distributed which will set forth the aggregate amount of shares of common stock covered by the registration statement being offered and the terms of the offering, including the name or names of any underwriters, dealers or agents. In addition, to the extent required, any discounts, commissions, concessions and other items constituting underwriters’ or agents’ compensation, as well as any discounts, commissions or concessions allowed or re-allowed or paid to dealers, will be set forth in such revised prospectus or prospectus supplement. Any such required prospectus or prospectus supplement, and, if necessary, a post-effective amendment to any registration statement, will be filed with the SEC to reflect the disclosure of additional information with respect to the distribution of the common stock covered by the registration statement.

The shares may also be sold in one or more of the following transactions, or in any transactions described in a prospectus or prospectus supplement:

block transactions in which a broker-dealer may sell all or a portion of the shares as agent but may position and resell all or a portion of the block as principal to facilitate the transaction;

purchase by a broker-dealer as principal and resale by the broker-dealer for its own account;

ordinary brokerage transactions and transactions in which a broker-dealer solicits purchasers;

sales “at the market” to or through a market maker or into an existing trading market, on an exchange or otherwise;

through the writing of options; or

sales in other ways not involving market makers or established trading markets, including direct sales to purchasers.

The shares that the Selling Stockholders sell by any of the methods described above may be sold to the public, in one or more transactions, either:

at a fixed public offering price or prices, which may be changed;

at market prices prevailing at the time of sale;

at prices related to prevailing market prices;

at varied prices determined at the time of sale; or

at negotiated prices.

Underwriters and agents may be entitled under agreements entered into with the Selling Stockholders to indemnification by us and/or the Selling Stockholders against certain civil liabilities, including liabilities under the Securities Act, or to contribution with respect to payments which the underwriters or agents may be required to make. Underwriters and agents may engage in transactions with, or perform services for, our company, our affiliates, the Selling Stockholders and their affiliates in the ordinary course of business.

The Selling Stockholders may also sell shares under Rule 144 under the Securities Act, if available.

Broker-dealers engaged by the Selling Stockholders may arrange for other brokers-dealers to participate in sales. Broker-dealers may receive commissions or discounts from the Selling Stockholders (or, if any broker-dealer acts as agent for the purchaser of shares, from the purchaser) in amounts to be negotiated, but, except as set forth in a supplement to this prospectus, in the case of an agency transaction not in excess of a customary brokerage commission in compliance with FINRA Rule 2440; and in the case of a principal transaction a markup or markdown in compliance with FINRA IM-2440.

In connection with the sale of the common stock or interests therein, the Selling Stockholders may enter into hedging transactions with broker-dealers or other financial institutions, which may in turn engage in short sales of the common stock in the course of hedging the positions they assume. The Selling Stockholders may also sell shares of the common stock short and deliver these securities to close out their short positions, or loan or pledge the common stock to broker-dealers that in turn may sell these securities. The Selling Stockholders may also enter into option or other transactions with broker-dealers or other financial institutions or the creation of one or more derivative securities which require the delivery to such broker-dealer or other financial institution of shares offered by this prospectus, which shares such broker-dealer or other financial institution may resell pursuant to this prospectus (as supplemented or amended to reflect such transaction).

The Selling Stockholders and any broker-dealers or agents that are involved in selling the shares may be deemed to be “underwriters” within the meaning of the Securities Act in connection with such sales. In such event, any commissions received by such broker-dealers or agents and any profit on the resale of the shares purchased by them may be deemed to be underwriting commissions or discounts under the Securities Act. Each Selling Stockholder has informed us that it does not have any written or oral agreement or understanding, directly or indirectly, with any person to distribute the common stock. In no event shall any broker-dealer receive fees, commissions and markups which, in the aggregate, would exceed eight percent (8%).

Because certain Selling Stockholders may be deemed to be an “underwriter” within the meaning of the Securities Act, they will be subject to the prospectus delivery requirements of the Securities Act including Rule 172 thereunder. There is no underwriter or coordinating broker acting in connection with the proposed sale of the resale shares by the Selling Stockholders.

We have agreed to keep this prospectus effective until the earlier of (i) the date on which the shares may be resold by the Selling Stockholders without registration by reason of Rule 144 under the Securities Act or any other rule of similar effect or (ii) all of the shares have been sold pursuant to this prospectus or Rule 144 under the Securities Act or any other rule of similar effect. The resale shares will be sold only through registered or licensed brokers or dealers if required under applicable state securities laws. In addition, in certain states, the resale shares may not be sold unless they have been registered or qualified for sale in the applicable state or an exemption from the registration or qualification requirement is available and is complied with.

Under applicable rules and regulations under the Exchange Act, any person engaged in the distribution of the resale shares may not simultaneously engage in market making activities with respect to the common stock for the applicable restricted period, as defined in Regulation M, prior to the commencement of the distribution. In addition, the Selling Stockholders will be subject to applicable provisions of the Exchange Act and the rules and regulations thereunder, including Regulation M, which may limit the timing of purchases and sales of shares of the common stock by the Selling Stockholders or any other person. We will make copies of this prospectus available to the Selling Stockholders and have informed them of the need to deliver a copy of this prospectus to each purchaser at or prior to the time of the sale (including by compliance with Rule 172 under the Securities Act).

The validity of the shares of common stock registered for resale hereby will be passed upon by Pryor Cashman LLP. Pryor Cashman owns 25,000 shares of our common stock.

The consolidated financial statements of Marina Biotech, Inc. as of December 31, 2010 and 2009, and for each of the years in the two-year period ended December 31, 2010, have been incorporated by reference herein in reliance upon the report of KPMG LLP, independent registered public accounting firm, incorporated by reference herein, and upon the authority of said firm as experts in accounting and auditing. The audit report covering the December 31, 2010 consolidated financial statements contains an explanatory paragraph that states that we have incurred recurring losses and have an accumulated deficit and have had recurring negative cash flows from operations, that raise substantial doubt about our ability to continue as a going concern. The consolidated financial statements do not include any adjustments that might result from the outcome of that uncertainty.

The financial statements of Cequent Pharmaceuticals, Inc. as of December 31, 2009 and 2008, and for the years then ended, incorporated by reference herein from our Current Report on Form 8-K filed with the SEC on February 9, 2011, have been audited by Wolf & Company, P.C., independent auditors, as stated in their report, which is incorporated herein by reference. Such financial statements have been so incorporated in reliance upon the report of such firm given upon their authority as experts in accounting and auditing.

We are subject to the reporting requirements of the Exchange Act, and in accordance with such laws we file annual, quarterly and current reports and other information with the SEC. The SEC maintains a website that contains annual, quarterly and current reports, proxy and information statements and other information filed with the SEC. The SEC’s website address is http://www.sec.gov. You may also read and copy any document we file with the SEC at the SEC’s public reference room, 100 F Street, N.E., Washington, D.C. 20549. Please call the SEC at 1-800-SEC-0330 for further information on the operation of its public reference room. The information we file with the SEC and other information about us is also available on our website at www.marinabiotech.com. However, the information on our website is not a part of, nor is such information to be deemed incorporated by reference into, this prospectus.

We have filed with the SEC a registration statement on Form S-3 (of which this prospectus is a part) under the Securities Act, with respect to the securities offered by this prospectus. This prospectus does not contain all of the information set forth in the registration statement, certain portions of which have been omitted as permitted by the rules and regulations of the SEC. Statements contained in this prospectus as to the contents of any contract or other document are not necessarily complete, and in each instance please see the copy of such contract or other document filed as an exhibit to the registration statement, each such statement being qualified in all respects by such reference and the exhibits and schedules thereto. For further information regarding us and the securities offered by this prospectus, please refer to the registration statement and such exhibits and schedules which may be obtained from the SEC at its principal office in Washington, D.C. upon payment of the fees prescribed by the SEC, or from its web site.

The SEC allows us to “incorporate by reference” into this prospectus the information we have filed with the SEC. The information we incorporate by reference into this prospectus is an important part of this prospectus. Any statement in a document we have filed with the SEC prior to the date of this prospectus and which is incorporated by reference into this prospectus will be considered to be modified or superseded to the extent a statement contained in this prospectus or any other subsequently filed document that is

incorporated by reference into this prospectus modifies or supersedes that statement. The modified or superseded statement will not be considered to be a part of this prospectus, except as modified or superseded.

We incorporate by reference into this prospectus the information contained in the documents listed below, which is considered to be a part of this prospectus:

our annual report on Form 10-K for the fiscal year ended December 31, 2010, filed with the SEC on March 23, 2011;

our current reports on Form 8-K, as filed with the SEC on February 9, 2011, February 9, 2011 and February 10, 2011;

the description of our common stock and the description of certain provisions of Delaware Law contained or incorporated by reference in our registration statement on Form 8-A, filed with the SEC on August 12, 1985, including any amendments or reports filed for the purposes of updating this description;

the description of our preferred stock purchase rights contained in our registration statement on Form 8-A, filed with the SEC on March 16, 2000, including any amendments or reports filed for the purposes of updating this description; and

future filings we make with the SEC under Sections 13(a), 13(c), 14, or 15(d) of the Exchange Act after the date of this prospectus but prior to the termination of the offering of the securities covered by this prospectus.

You may obtain copies of these filings, at no cost, by writing or telephoning us at the following address:

The following sets forth the costs and expenses payable by us in connection with the distribution of the securities being registered. All amounts except the SEC registration fee are estimated.

Our Restated Certificate of Incorporation currently provides that our board of directors has the authority to utilize, to the fullest extent possible, the indemnification provisions of Sections 102(b)(7) and 145 of the Delaware General Corporation Law (the “DGCL”), and our directors and officers are provided with the broadest available indemnification coverage. Such indemnification for our directors and officers is mandatory. Our Restated Certificate of Incorporation also expressly provides that the advancement of expenses is mandatory and not subject to the discretion of our board of directors, except that any of our directors or officers who request advancement must undertake to repay the advanced amounts if it is determined that such person is not entitled to be indemnified by us. Further, our Restated Certificate of Incorporation contains provisions to eliminate the liability of our directors to us or our stockholders to the fullest extent permitted by Section 102(b)(7) of the DGCL, as amended from time to time.

Section 102(b)(7) of the DGCL permits a corporation to provide in its certificate of incorporation that a director of the corporation shall not be personally liable to the corporation or its stockholders for monetary damages for breach of fiduciary duty as a director, except for liability (i) for any breach of the director’s duty of loyalty to the corporation or its stockholders, (ii) for acts or omissions not in good faith or which involve intentional misconduct or a knowing violation of law, (iii) for unlawful payments of dividends or unlawful stock repurchases, redemptions or other distributions, or (iv) for any transaction from which the director derived an improper personal benefit. Our Restated Certificate of Incorporation provides for such limitation of liability.

Under Section 145 of the DGCL, a corporation may indemnify any individual made a party or threatened to be made a party to any type of proceeding, other than an action by or in the right of the corporation, because he or she is or was an officer, director, employee or agent of the corporation or was serving at the request of the corporation as an officer, director, employee or agent of another corporation or entity against expenses, judgments, fines and amounts paid in settlement actually and reasonably incurred in connection with such proceeding: (1) if he or she acted in good faith and in a manner he or she reasonably believed to be in or not opposed to the best interests of the corporation; or (2) in the case of a criminal proceeding, he or she had no reasonable cause to believe that his or her conduct was unlawful. A corporation may indemnify any individual made a party or threatened to be made a party to any threatened, pending or completed action or suit brought by or in the right of the corporation because he or she was an officer, director, employee or agent of the corporation, or is or was serving at the request of the corporation as a director, officer, employee or agent of another corporation or other entity, against expenses actually and reasonably incurred in connection with such action or suit if he or she acted in good faith and in a manner he or she reasonably believed to be in or not opposed to the best interests of the corporation, provided that such indemnification will be denied if the individual is found liable to the corporation unless, in such a case, the court determines the person is nonetheless entitled to indemnification for such expenses.

A corporation must indemnify a present or former director or officer who successfully defends himself or herself in a proceeding to which he or she was a party because he or she was a director or officer of the corporation against expenses actually and reasonably incurred by him or her. Expenses incurred by an officer or director, or any employees or agents as deemed appropriate by the board of directors, in defending civil or criminal proceedings may be paid by the corporation in advance of the final disposition of such proceedings upon receipt of an undertaking by or on behalf of such director, officer, employee or agent to repay such amount if it shall ultimately be determined that he or she is not entitled to be indemnified by the corporation. The Delaware law regarding indemnification and expense advancement is not exclusive of any other rights which may be granted by our restated certificate of incorporation or restated bylaws, a vote of stockholders or disinterested directors, agreement or otherwise.

We maintain a policy of directors and officer’s liability insurance covering certain liabilities incurred by our directors and officers in connection with the performance of their duties.

Insofar as indemnification for liabilities arising under the Securities Act is permitted for our directors, officers or controlling persons, pursuant to the above mentioned statutes or otherwise, we understand that the SEC is of the opinion that such indemnification may contravene federal public policy, as expressed in the Securities Act, and therefore, is unenforceable. Accordingly, in the event that a claim for such indemnification is asserted by any of our directors, officers or controlling persons, and the SEC is still of the same opinion, we (except insofar as such claim seeks reimbursement from us of expenses paid or incurred by a director, officer of controlling person in successful defense of any action, suit or proceeding) will, unless the matter has theretofore been adjudicated by precedent deemed by our counsel to be controlling, submit to a court of appropriate jurisdiction the question whether or not indemnification by it is against public policy as expressed in the Securities Act and will be governed by the final adjudication of such issue.

At present, there is no pending litigation or proceeding involving any of our directors, officers or employees as to which indemnification is sought, nor are we aware of any threatened litigation or proceeding that may result in claims for indemnification.

See the Exhibit Index attached to this registration statement that is incorporated herein by reference.

(1) To file, during any period in which offers or sales are being made, a post-effective amendment to this registration statement:

(i) To include any prospectus required by Section 10(a)(3) of the Securities Act;

(ii) To reflect in the prospectus any facts or events arising after the effective date of the registration statement (or the most recent post-effective amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information set forth in the registration statement. Notwithstanding the foregoing, any increase or decrease in volume of securities offered (if the total dollar value of securities offered would not exceed that which was registered) and any deviation from the low or high end of the estimated maximum offering range may be reflected in the form of prospectus filed with the Securities and Exchange Commission pursuant to Rule 424(b) if, in the aggregate, the changes in volume and price represent no more than a 20 percent change in the maximum aggregate offering price set forth in the “Calculation of Registration Fee” table in the effective registration statement; and

(iii) To include any material information with respect to the plan of distribution not previously disclosed in the registration statement or any material change to such information in the registration statement;

provided,however, that paragraphs (1)(i), (1)(ii) and (1)(iii) do not apply if the registration statement is on Form S-3 and the information required to be included in a post-effective amendment by those paragraphs is contained in periodic reports filed with or furnished to the Securities and Exchange Commission by the registrant pursuant to Section 13 or 15(d) of the Exchange Act (15 U.S.C. 78m or 78o(d)) that are incorporated by reference in the registration statement, or is contained in a form of prospectus filed pursuant to Rule 424(b) (§ 230.424(b) of this chapter) that is part of the registration statement.

(2) That, for the purpose of determining any liability under the Securities Act, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

(3) To remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the offering.

(4) That, for the purpose of determining liability under the Securities Act of 1933 to any purchaser:

(i) Each prospectus filed by the registrant pursuant to Rule 424(b)(3) shall be deemed to be part of the registration statement as of the date the filed prospectus was deemed part of and included in the registration statement; and

(ii) Each prospectus required to be filed pursuant to Rule 424(b)(2), (b)(5), or (b)(7) as part of a registration statement in reliance on Rule 430B relating to an offering made pursuant to Rule 415(a)(1)(i), (vii), or (x) for the purpose of providing the information required by section 10(a) of the Securities Act of 1933 shall be deemed to be part of and included in the registration statement as of the earlier of the date such form of prospectus is first used after effectiveness or the date of the first contract of sale of securities in the offering described in the prospectus. As provided in Rule 430B, for liability purposes of the issuer and any person that is at that date an underwriter, such date shall be deemed to be a new effective date of the registration statement relating to the securities in the registration statement to which that prospectus relates, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof. Provided, however, that no statement made in a registration statement or prospectus that is part of the registration statement or made in a document incorporated or deemed incorporated by reference into the registration statement or prospectus that is a part of the registration statement will, as to a purchaser with a time of contract sale prior to such effective date, supersede or modify any statement that was made in the registration statement or prospectus that was a part of the registration statement or made in any such document immediately prior to such effective date.

The undersigned registrant hereby undertakes that, for purposes of determining any liability under the Securities Act, each filing of the registrant’s annual report pursuant to Section 13(a) or 15(d) of the Exchange Act and (and, where applicable, each filing of an employee benefit plan’s annual report pursuant to Section 15(d) of the Exchange Act) that is incorporated by reference in the registration statement shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

Insofar as indemnification for liabilities arising under the Securities Act may be permitted to directors, officers and controlling persons of the registrant pursuant to the foregoing provisions, or otherwise, the registrant has been advised that in the opinion of the Securities and Exchange Commission such indemnification is against public policy as expressed in the Securities Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrant of expenses incurred or paid by a director, officer or controlling person of the registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Securities Act and will be governed by the final adjudication of such issue.

Pursuant to the requirements of the Securities Act of 1933, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-3 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the city of Bothell, State of Washington, on the 2325^rdth day of March, 2011.


MARINA BIOTECH, INC.

By:	/s/ J. Michael French
Name:		J. Michael French
Title:		President and Chief
		Executive Officer

Pursuant to the requirements of the Securities Act of 1933, as amended, this registration statement has been signed by the following persons in the capacities and on the dates indicated.



Title Of Each Class Of Securities To Be Registered	Amount to be Registered(1)	Proposed Maximum Offering Price Per Share(2)	Proposed Maximum Aggregate Offering Price	Amount Of Registration Fee
Common Stock, $0.006 par value per share	2,518,929 shares	$0.67	$1,687,683(2)	$196.00(3)


	Shares of Common Stock Owned Prior to Offering		Number of Shares Being Offered		Shares Owned After This Offering(1)
Name of Beneficial Owner					Number		Percent
Canaccord Genuity, Inc.(2)		289,436		289,436		—		—
BioMed Realty, L.P.(3)		2,115,727		2,115,727		—		—
Ribotask ApS (4)		114,538		113,766		772		*


SEC Registration Fee	$	196.00
Legal Fees and Expenses		5,000.00
Accounting Fees and Expenses		10,000.00
Miscellaneous		1,000.00

Total:	$	16,196.00


Signature	Title	Date

/s/ J. Michael French	President, Chief Executive Officer and a Director (Principal Executive Officer)	March ~~23,~~25, 2011
J. Michael French

/s/ Peter S. Garcia	Secretary and Chief Financial Officer (Principal Financial Officer and Principal Accounting Officer)	March ~~23,~~25, 2011
Peter S. Garcia

*	Director	March ~~23,~~25, 2011
James M. Karis

	Director
Chiang J. Li, M.D.

*	Director	March ~~23,~~25, 2011
Peter D. Parker

*	Director	March ~~23,~~25, 2011
Gregory Sessler

	Director
Michael D. Taylor, Ph.D.


	PAGE

About this Prospectus		1

Forward-Looking Statements		2

About the Company		3

Risk Factors		4

Use of Proceeds		22

Description of Capital Stock		22

Selling Stockholders		25

Plan of Distribution		27

Legal Matters		30

Experts		30

Where You Can Find More Information		30

Incorporation by Reference		30


Exhibit No.		Description

3.1		Restated Certificate of Incorporation of the Registrant dated July 20, 2005 (filed as Exhibit 3.1 to our Current Report on Form 8-K dated July 20, 2005, and incorporated herein by reference).

3.2		Certificate of Amendment of the Restated Certificate of Incorporation of the Registrant, dated June 10, 2008 (filed as Exhibit 3.1 to our Current Report on Form 8-K dated June 10, 2008, and incorporated herein by reference).

3.3		Certificate of Amendment of the Restated Certificate of Incorporation of the Registrant, dated July 21, 2010 (filed as Exhibit 3.1 to our Current Report on Form 8-K filed on July 21, 2010, and incorporated herein by reference).

3.4		Certificate of Amendment of the Restated Certificate of Incorporation of the Registrant, dated July 21, 2010 (filed as Exhibit 3.1 to our Current Report on Form 8-K filed July 23, 2010, and incorporated herein by reference).

3.5		Amended and Restated Bylaws of the Registrant dated September 19, 2007 (filed as Exhibit 3.1 to our Current Report on Form 8-K dated September 19, 2007, and incorporated herein by reference).

3.6		Certificate of Designation, Rights and Preferences of Series A Junior Participating Preferred Stock dated January 17, 2007 (filed as Exhibit 3.1 to our Current Report on Form 8-K dated January 19, 2007, and incorporated herein by reference).

3.7		Amended Designation, Rights, and Preferences of Series A Junior Participating Preferred Stock, dated June 10, 2008 (filed as Exhibit 3.2 to our Current Report on Form 8-K dated June 10, 2008, and incorporated herein by reference).

4.1		Rights Agreement, dated February 22, 2000, between the Registrant and American Stock Transfer & Trust Company as Rights Agent (filed as Exhibit 1 to our Current Report on Form 8-K dated February 22, 2000, and incorporated herein by reference).

4.2		Amendment No. 1 to Rights Agreement dated as of January 17, 2007 by and between the Registrant and American Stock Transfer and Trust Company (filed as Exhibit 4.1 to our Current Report on Form 8-K dated January 19, 2007, and incorporated herein by reference).

4.3		Amendment No. 2 to Rights Agreement dated as of March 17, 2010 by and between the Registrant and American Stock Transfer and Trust Company (filed as Exhibit 4.1 to our Current Report on Form 8-K dated March 5, 2010, and incorporated herein by reference).

4.4		Amendment No. 3 to Rights Agreement dated as of March 31, 2010 by and between the Registrant and American Stock Transfer and Trust Company (filed as Exhibit 4.3 to our Current Report on Form 8-K dated March 31, 2010, and incorporated herein by reference).

4.5		Form of Amended and Restated Common Stock Purchase Warrant originally issued by the Registrant in April 2008 (filed as Exhibit 10.2 to our Quarterly Report on Form 10-Q for the quarter ended June 30, 2009, and incorporated herein by reference).

4.6		Form of Common Stock Purchase Warrant issued by the Registrant in June 2009 (filed as Exhibit 10.3 to our Current Report on Form 8-K dated June 10, 2009, and incorporated herein by reference).



4.7		Form of Common Stock Purchase Warrant issued by the Registrant in December 2009 (filed as Exhibit 4.2 to our Current Report on Form 8-K dated December 22, 2009, and incorporated herein by reference).

4.8		Form of Common Stock Purchase Warrant issued by the Registrant in January 2010 (filed as Exhibit 4.1 to our Current Report on Form 8-K dated January 13, 2010, and incorporated herein by reference).

4.9		Form of Subscription Investment Unit issued by the Registrant on November 5, 2010 (filed as Exhibit 4.1 to our Current Report on Form 8-K dated November 4, 2010, and incorporated herein by reference).

4.10		Form of Common Stock Purchase Warrant issued by the Registrant on November 8, 2010 (filed as Exhibit 4.2 to our Current Report on Form 8-K dated November 4, 2010, and incorporated herein by reference).

4.11		Form of Warrant Certificate issued by the Registrant in February 2011 (filed as Exhibit 4.1 to our Current Report on Form 8-K dated February 10, 2011, and incorporated herein by reference).

4.12		Form of Warrant Agreement by and between the Registrant and American Stock Transfer & Trust Company, LLC (filed as Exhibit 4.2 to our current Report on Form 8-K dated February 10, 2011, and incorporated herein by reference).

5.1		Opinion of Pryor Cashman LLP (filed as Exhibit 5.1 to our Registration Statement on Form S-3 filed with the SEC on March 14, 2011, and incorporated herein by reference).

23.1		Consent of KPMG LLP, independent registered public accounting firm. (1)

23.2		Consent of Wolf & Company, P.C., independent auditors. (1)

23.3		Consent of Pryor Cashman LLP (included in Exhibit 5.1).

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