Title of securities to be registered		Amount to be registered (1)				Proposed maximum offering price per share (2)				Proposed maximum aggregate offering price (2)				Amount of registration fee
Common Stock, $0.01 par value			4,500,000			$	1.43			$	6,435,000			$	836

(1)	Represents 4,500,000 shares of common stock that are issuable pursuant to a common stock purchase agreement with the selling stockholder named herein. Pursuant to Rule 416(a) of the Securities Act of 1933, as amended, this registration statement also covers any additional shares of common stock which may become issuable to prevent dilution from stock splits, stock dividends and similar events.
(2)	Estimated in accordance with Rules 457(c) and (h) under the Securities Act solely for the purposes of calculating the registration fee. The price per share represents the average high and low sales prices of the Common Stock as reported on the NASDAQ Capital Market on November 6, 2019.

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 whichthat 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.

 

 

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The information in this prospectus is not complete and may be changed. The selling stockholdersstockholder may not sell these securities pursuant to this prospectus until the registration statement filed with the Securities and Exchange Commission is effective. This prospectus is not an offer to sell these securities, and the selling stockholder is not soliciting offers to buy these securities, in any jurisdictionstate where the offer or sale of these securities is not permitted.

 

PROSPECTUS, SUBJECT TO COMPLETION, DATED NOVEMBER 8, 2019NOVEMBER 22, 2017

 

PROSPECTUS

1,314,443 4,500,000 Shares of Common Stock

Issuable upon Exercise of Outstanding Warrants

 

Common Stock

 

 

This prospectus relates to the resale, from time to time, by the selling stockholders identified in this prospectus under the caption “Selling Stockholders,”sale of up to 1,314,4434,500,000 shares of our common stock par value $0.01 per share, including (i) 1,166,250 shares issuable upon exercise of certain outstanding investor common stock purchase warrants and (ii) 66,000 shares issuable upon exercise of certain outstanding representative common stock purchase warrants. We are not selling any shares of common stock underby Aspire Capital Fund, LLC. Aspire Capital is also referred to in this prospectus andas the selling stockholder. The prices at which the selling stockholder may sell the shares will be determined by the prevailing market price for the shares or in negotiated transactions. We will not receive any proceeds from the sale of the shares of common stock by the selling stockholders. We willstockholder. However, we may receive proceeds from cash exercise of the warrants which, if exercised in cash with respectup to all of the 1,232,250 shares of common stock, would result in gross proceeds of approximately $7.4$10.0 million to us. The selling stockholders will bear all commissions and discounts, if any, attributable tofrom the sale of our common stock to the shares.selling stockholder, pursuant to a common stock purchase agreement entered into with the selling stockholder on October 28, 2019, once the registration statement, of which this prospectus is a part, is declared effective.

 

The selling stockholders may sellstockholder is an “underwriter” within the meaning of the Securities Act of 1933, as amended. We will pay the expenses of registering these shares, of our common stock offeredbut all selling and other expenses incurred by this prospectus from time to time on terms tothe selling stockholder will be determined atpaid by the time of sale through ordinary brokerage transactions or through any other means described in this prospectus under the caption “Plan of Distribution.” The shares of common stock may be sold at fixed prices, at market prices prevailing at the time of sale, at prices related to prevailing market price or at negotiated prices.selling stockholder.

 

Our common stock is listed on The NASDAQ Capitalthe Nasdaq Capital Market under the ticker symbol “CLSN.” On November 21, 2017,6, 2019, the last reported closing sale price per share of our common stock on The NASDAQ Capital Market was $2.86$1.43 per share.

 

You should read this prospectus and any prospectus supplement, together with additional information described under the headings “Incorporation of Certain Documents by Reference” and “Where You Can Find More Information,” carefully before you invest in any of our securities.

Investing in our common stocksecurities involves a high degree of risk. Before making an investment decision, please readSee “Risk Factors” on page 138 of this prospectus.

 

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

 

The date of this prospectus is               , 2017.

2019.

 

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TABLE OF CONTENTS

 

	Page
ABOUT THIS PROSPECTUS SUMMARY	1
RISK FACTORS	8
SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS	9
THE ASPIRE CAPITAL TRANSACTION	10
USE OF PROCEEDS	14
DILUTION	15
DESCRIPTION OF CAPITAL STOCK	16
SELLING STOCKHOLDER	21
PLAN OF DISTRIBUTION	22
LEGAL MATTERS	24
EXPERTS	24
WHERE YOU CAN FIND ADDITIONALMORE INFORMATION	1 24
INCORPORATION OF CERTAIN INFORMATION INCORPORATED BY REFERENCE	2
FORWARD-LOOKING STATEMENTS	3
PROSPECTUS SUMMARY	4
RISK FACTORS	13
USE OF PROCEEDS	14
MARKET INFORMATION FOR OUR COMMON STOCK	15
DESCRIPTION OF CAPITAL STOCK	16
SELLING STOCKHOLDERS	19
PLAN OF DISTRIBUTION	21
LEGAL MATTERS	22
EXPERTS	22 25

 

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ABOUT THIS PROSPECTUS

This prospectus relates to the resale, from time to time, byNeither we nor the selling stockholders identifiedstockholder have authorized anyone to provide you with additional information or information different from that contained in this prospectus under the caption “Selling Stockholders,” of up to 1,314,443shares of our common stock, par value $0.01 per share, including (i) 1,166,250 shares issuable upon exercise of certain outstanding investor common stock purchase warrants and (ii) 66,000 shares issuable upon exercise of certain outstanding representative common stock purchase warrants. As described below under “Description of the Private Placement” on page 10 of this prospectus, (i) on October 4, 2018, 1,166,250 shares of common stock will become exercisable at $6.20 per share by the selling stockholders and (ii) on April 30, 2018, 66,000 shares of common stock will become exercisable at $2.87 per share by the selling stockholders. We are not selling any shares of common stock under this prospectus and will not receive any proceeds from the sale of shares of common stock by the selling stockholders. We will receive proceeds from the cash exercise of the warrants which, if exercised in cash with respect to all of the 1,232,250 shares of common stock, would result in gross proceeds of $7,420,170 to us.

This prospectus is part of a registration statement on Form S-1 that we filed with the Securities and Exchange Commission, (SEC). It omits someor the SEC. We take no responsibility for, and can provide no assurance as to the reliability of, theany other information that others may give you. The selling stockholder is offering to sell, and seeking offers to buy, our common stock only in jurisdictions where offers and sales are permitted. The information contained in the registration statement and referencethis prospectus is made to the registration statement for further information with regard to us and the securities being offered by the selling stockholders. Any statement contained in the prospectus concerning the provisions of any document filedaccurate only as an exhibit to the registration statement or otherwise filed with the SEC is not necessarily complete, and in each instance, reference is made to the copy of the document filed.

You should readdate of this prospectus, any documents that we incorporate by reference in this prospectus andregardless of the additional information described below under “Where You Can Find Additional Information” and “Information Incorporated By Reference” before making an investment decision. You should rely only on the information contained or incorporated by reference in this prospectus. We have not authorized any other person to provide you with different information. If anyone provides you with additional, different or inconsistent information, you should not rely on it. This prospectus is not an offer to sell these securities and it is not soliciting an offer to buy these securities in any jurisdiction where the offer or sale is not permitted.

You should not assume that the information intime of delivery of this prospectus or any documents we incorporate by reference herein is accurate assale of any date other than the date on the frontshares of those documents.our common stock. Our business,business, financial condition, results of operations and prospects may have changed since those dates.  that date.

 

UnlessNeither we nor the context indicates otherwise, as used inselling stockholder have taken any action that would permit this offering or possession or distribution of this prospectus the terms “Celsion,” “the Company,” “we,” “us” and “our” refer to Celsion Corporation, a Delaware corporation, and its wholly-owned subsidiary CLSN Laboratories, Inc., also a Delaware corporation. The Celsion brand and product names, including but not limited to Celsion^® and ThermoDox^® contained in this prospectus are trademarks, registered trademarks or service marks of Celsion Corporation or its subsidiaryany jurisdiction where action for that purpose is required, other than in the United States and certain other countries. This document may also contain references to trademarks and service marks of other companies that are the property of their respective owners.

WHERE YOU CAN FIND MORE INFORMATION

We are subject to the information requirements of the Securities Exchange Act of 1934, as amended (the Exchange Act). In accordance with the Exchange Act, we file annual, quarterly and current reports, proxy statements and other information with the SEC. Such reports, proxy statements and other information filed by us are available to the public free of charge at www.sec.gov. You may also read and copy any document we file with the SEC at the public reference facilities maintained by the SEC at 100 F Street, N.E., Washington, D.C. 20549. You may obtain information on the operation of the public reference facilities by calling the SEC at 1-800-SEC-0330. Copies of certain information filed by us with the SEC are also available on our website at www.celsion.com. The information available on or through our website is not partStates. Persons who have come into possession of this prospectus in a jurisdiction outside the United States are required to inform themselves about and should not be relied upon.

This prospectus is partto observe any restrictions relating to the offering of a registration statement that we filed with the SEC. This prospectus omits some information contained in the registration statement in accordance with SEC rules and regulations. You should review the information and exhibits in the registration statement for further information about usshares of common stock and the securities being offered hereby. Statements in this prospectus concerning any document we filed as an exhibit to the registration statement or that we otherwise filed with the SEC are not intended to be comprehensive and are qualified by reference to the filings. You should review the complete document to evaluate these statements.

INFORMATION INCORPORATED BY REFERENCE

SEC rules allow us to “incorporate by reference” into this prospectus much of the information we file with the SEC, which means that we can disclose important information to you by referring you to those publicly available documents. The information that we incorporate by reference into this prospectus is considered to be partdistribution of this prospectus. These documents may include Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q and Current Reports on Form 8-K, as well as proxy statements. You should read the information incorporated by reference because it is an important part of this prospectus.

 

This prospectus incorporates by reference important information as further described under “Where You Can Find More Information” and “Incorporation of Certain Information by Reference.” We may amend or supplement this prospectus from time to time by filing amendments or supplements. You should read the entire prospectus and any amendments or supplements, together with any documents listthat we incorporate by reference in this prospectus, before making an investment decision.

i

ed below, otherSUMMARY

This summary highlights certain information about us, this offering and selected information contained in the prospectus. This summary is not complete and does not contain all of the information that you should consider before deciding whether to invest in our common stock. For a more complete understanding of our company and this offering, we encourage you to read and consider the more detailed information in the prospectus, including “Risk Factors” and the financial statements and related notes. Unless we specify otherwise, all references in this prospectus to “Celsion,” “we,” “our,” “us” and “our company” refer toCelsion Corporation.

CELSION CORPORATION

Company Overview

We are a fully integrated development clinical stage oncology drug company focused on advancing innovative cancer treatments, including directed chemotherapies, DNA-mediated immunotherapy and RNA based therapies. Our lead product candidate is ThermoDox®, a proprietary heat-activated liposomal encapsulation of doxorubicin, currently in a Phase III clinical trial for the treatment of primary liver cancer (the “OPTIMA Study”). Second in our pipeline is GEN-1, a DNA-mediated immunotherapy for the localized treatment of ovarian cancer. These investigational products are based on technologies that provide the platform for the future development of a range of therapeutics for difficult-to-treat forms of cancer. The first technology is Lysolipid Thermally Sensitive Liposomes, a heat sensitive liposomal based dosage form that targets disease with known chemotherapeutics in the presence of mild heat. The second technology is TheraPlas, a novel nucleic acid-based treatment for local transfection of therapeutic DNA plasmids. With these technologies we are working to develop and commercialize more efficient, effective and targeted oncology therapies that maximize efficacy while minimizing side effects common to cancer treatments.

ThermoDox®

ThermoDox® is being evaluated in a Phase III clinical trial for primary liver cancer, which we call the OPTIMA Study, which was initiated in 2014. ThermoDox® is a liposomal encapsulation of doxorubicin, an approved and frequently used oncology drug for the treatment of a wide range of cancers. Localized heat at hyperthermia temperatures (greater than those documents40° Celsius) releases the encapsulated doxorubicin from the liposome enabling high concentrations of doxorubicin to be deposited preferentially in and around the targeted tumor.

The OPTIMA Study. The OPTIMA Study represents an evaluation of ThermoDox® in combination with a first line therapy, RFA, for newly diagnosed, intermediate stage HCC patients. HCC incidence globally is approximately 755,000 new cases per year and is the third largest cancer indication globally. Approximately 30% of newly diagnosed patients can be addressed with RFA.

On February 24, 2014, we announced that the United States Food and Drug Administration, or the portionsFDA, provided clearance for the OPTIMA Study, which is a pivotal, double-blind, placebo-controlled Phase III trial of those documents deemedThermoDox®, in combination with standardized RFA, for the treatment of primary liver cancer. The trial design of the OPTIMA Study is based on the comprehensive analysis of data from an earlier clinical trial called the HEAT Study. The OPTIMA Study is supported by a hypothesis developed from an overall survival analysis of a large subgroup of patients from the HEAT Study.

The OPTIMA Study was designed with extensive input from globally recognized HCC researchers and expert clinicians and after receiving formal written feedback from the FDA. The OPTIMA Study was designed to enroll up to 550 patients globally at approximately 65 clinical sites in the U.S., Canada, European Union (EU), China and other countries in the Asia-Pacific region and will evaluate ThermoDox® in combination with standardized RFA, which will require a minimum of 45 minutes across all investigators and clinical sites for treating lesions three to seven centimeters, versus standardized RFA alone. The primary endpoint for this clinical trial is overall survival , or OS, and the secondary endpoints are progression free survival and safety. The statistical plan calls for two interim efficacy analyses by an independent Data Monitoring Committee, or DMC.

Post-hoc data analysis from our earlier Phase III HEAT Study suggest that ThermoDox® may substantially improve OS, when compared to the control group, in patients if their lesions undergo a 45-minute RFA procedure standardized for a lesion greater than 3 cm in diameter. Data from nine OS sweeps have been conducted since the top line progression free survival, or PFS, data from the HEAT Study were announced in January 2013, with each data set demonstrating substantial improvement in clinical benefit over the control group with statistical significance. On August 15, 2016, we announced updated results from its final retrospective OS analysis of the data from the HEAT Study. These results demonstrated that in a large, well bounded, subgroup of patients with a single lesion (n=285, 41% of the HEAT Study patients), treatment with a combination of ThermoDox® and optimized RFA provided an average 54% risk improvement in OS compared to optimized RFA alone. The Hazard Ratio, or HR, at this analysis is 0.65 (95% CI 0.45 - 0.94) with a p-value of 0.02. Median OS for the ThermoDox® group has been reached which translates into a two-year survival benefit over the optimized RFA group (projected to be furnishedgreater than 80 months for the ThermoDox® plus optimized RFA group compared to less than 60 months projection for the optimized RFA only group).

While this information should be viewed with caution since it is based on a retrospective analysis of a subgroup, we also conducted additional analyses that further strengthen the evidence for the HEAT Study subgroup. We commissioned an independent computational model at the University of South Carolina Medical School. The results unequivocally indicate that longer RFA heating times correlate with significant increases in doxorubicin concentration around the RFA treated tissue. In addition, we conducted a prospective preclinical study in 22 pigs using two different manufacturers of RFA and not filedhuman equivalent doses of ThermoDox® that clearly support the relationship between increased heating duration and doxorubicin concentrations.

We completed enrollment of 556 patients in the Phase III OPTIMA Study in August 2018. Data for the study will be reviewed as it matures up to two interim analyses expected to be conducted in the fourth quarter of 2019 and in the first half of 2020. We expect that the final efficacy analysis, if necessary, will be completed in the first half of 2021. If the study proves to provide a clinically meaningful improvement in overall survival, we will immediately apply for marketing authorization in the US, Europe and China. ThermoDox® has received U.S. FDA Fast Track Designation and has been granted orphan drug designation for primary liver cancer in both the U.S. and the EU. Additionally, the U.S. FDA has provided ThermoDox® with a 505(b)(2) registration pathway. Subject to a successful trial, the OPTIMA Study has been designed to support registration in all key primary liver cancer markets. We fully expect to submit registrational applications in the U.S., Europe and China. We expect to submit and believes that applications will be accepted in South Korea, Taiwan and Vietnam, three other significant markets for ThermoDox® if it were to receive approval in Europe, China or the U.S.

On December 18, 2018, we announced that the DMC for the OPTIMA Study completed its last scheduled review of all patients enrolled in the trial and unanimously recommended that the OPTIMA Study continue according to protocol to its final data readout. The DMC’s recommendation was based on the Committee’s assessment of safety and data integrity of all patients randomized in the trial as of October 4, 2018. The DMC reviewed study data at regular intervals throughout the patient enrollment period, with the primary responsibilities of ensuring the safety of all patients enrolled in the study, the quality of the data collected, and the continued scientific validity of the study design. As part of its review of all 556 patients enrolled into the trial, the DMC evaluated a quality matrix relating to the total clinical data set, confirming the timely collection of data, that all data are current as well as other data collection and quality criteria.

On August 5, 2019, the Company announced that the prescribed number of events has been reached for the first prespecified interim analysis of the OPTIMA Phase III Study with ThermoDox® plus RFA in patients with HCC, or primary liver cancer. Following preparation of the data, the first interim analysis was conducted by the Independent Data Monitoring Committee (iDMC) on November 1, 2019. This timeline was consistent with the Company’s stated expectations and is necessary to provide a full and comprehensive data set that may represent the potential for a successful trial outcome. In accordance with SEC rules:the statistical plan, this initial interim analysis has a target of 118 events, or 60% of the total number required for the final analysis. At the time of the data cutoff, the Company received reports of 128 events. The hazard ratio for success at 128 events is approximately 0.63, which represents a 37% reduction in the risk of death compared with RFA alone and is consistent with the 0.65 hazard ratio that was observed in the prospective HEAT Study subgroup, which demonstrated a two-year overall survival advantage and a median time to death of more than seven and a half years.

On November 4, 2019, the Company announced that the independent Data Monitoring Committee (iDMC) unanimously recommended the OPTIMA Study continue according to protocol. The recommendation was based on a review of blinded safety and data integrity from 556 patients enrolled in the Company’s multinational, double-blind, placebo-controlled pivotal Phase III study with ThermoDox® plus RFA in patients with hepatocellular carcinoma (HCC), or primary liver cancer.

The iDMC’s pre-planned interim efficacy review followed 128 patient events, or deaths, which occurred in August 2018. Data presented demonstrated that PFS and OS data appear to be tracking with patient data observed at a similar point in the Company’s subgroup of patients followed prospectively in the earlier Phase III HEAT Study, upon which the OPTIMA Study is based.

The data review demonstrated the following:

 

	●	our Annual Report on Form 10-K forThe OPTIMA Study patient demographics and risk factors are consistent with what the fiscal year ended December 31, 2016, filedCompany observed in the HEAT Study subgroup with the SEC on March 24, 2017;
	●	our Quarterly Report on Form 10-Q for the quarter ended March 31, 2017, filed with the SEC on May 12, 2017;
	●	our Quarterly Report on Form 10-Q for the quarter ended June 30, 2017, filed with the SEC on August 14, 2017; all data quality metrics meeting expectations.
	●	our Quarterly Report on Form 10-QMedian PFS for the quarter ended September 30, 2017, filedOPTIMA Study reached 17 months as of August 2019. These blinded data compare favorably with 16 months median PFS for the SEC on November 14, 2017; 285 patients in the HEAT Study subgroup of patients treated with RFA >45 minutes and followed prospectively for overall survival.
	●	our Current Reports on Form 8-K filedMedian OS for the OPTIMA Study has not been reached as of August 5, 2019, however median OS appears to be consistent with the SEC on February 15, 2017, May 16, 2017, May 26, 2017, June 6, 2017, June 9, 2017, June 19, 2017, June 22, 2017, June 23, 2017, June 26, 2017, July 6, 2017, July 11, 2017, August 15, 2017, September 21, 2017, October 4, 2017, October 27, 2017HEAT Study subgroup of patients treated with RFA >45 minutes and October 31, 2017; followed prospectively for overall survival.
	●	our Definitive Proxy Statement on Schedule 14A filed withThe OPTIMA Study has lost only 4 patients to follow-up from the SEC on April 4, 2017; andinitiation of the trial in September 2014 through August 2019 while the trial design allows for 3% risk for loss per year, which at this point would have exceeded 60 patients.

While the Company has not unblinded the study to report a hazard ratio, PFS and OS are tracking similarly to the subgroup of patients who received more than 45 minutes of RFA in our HEAT Study and followed prospectively for more than three years. This subgroup in the HEAT study demonstrated a 2-year overall survival advantage and a median time to death of more than 7 ½ years. This tracking appears to bode well for success at the next pre-planned interim efficacy analysis, which is intended after a minimum of 158 patient deaths and is projected to occur during the second quarter of 2020. The hazard ratio for success at 158 events is 0.70. This is below the hazard ratio of 0.65 observed for the 285 patients in the HEAT Study subgroup of patients treated with RFA > 45 minutes.

On August 13, 2019, we announced that results from an independent analysis of our ThermoDox^® HEAT Study conducted by the National Institutes of Health, or NIH, were published in the peer-reviewed publication,Journal of Vascular and Interventional Radiology. The analysis was conducted by the intramural research program of the NIH and the NIH Center for Interventional Oncology (CIO), with the full data set from the Company’s HEAT Study. The analysis evaluated the full data set to determine if there was a correlation between baseline tumor volume and radiofrequency ablation (RFA) heating time (minutes/tumor volume in milliliters), with or without ThermoDox® treatment, for patients with HCC. The NIH analysis was conducted under the direction of Dr. Bradford Wood, MD, Director, NIH Center for Interventional Oncology and Chief, NIH Clinical Center Interventional Radiology.

The article titled, “RFA Duration Per Tumor Volume May Correlate With Overall Survival in Solitary Hepatocellular Carcinoma Patients Treated With RFA Plus Lyso-thermosensitive Liposomal Doxorubicin,” discussed the NIH analysis of results from 437 patients in the HEAT Study (all patients with a single lesion representing 62.4% of the study population). The key finding was that increased RFA heating time per tumor volume significantly improved overall survival (OS) in patients with single-lesion HCC who were treated with RFA plus ThermoDox^®, compared to patients treated with RFA alone. A one-unit increase in RFA duration per tumor volume was shown to result in about a 20% improvement in OS for patients administered ThermoDox®, compared to RFA alone. The authors conclude that increasing RFA heating time in combination with ThermoDox® significantly improves OS and establishes an improvement of over two years versus the control arm when the heating time per milliliter of tumor is greater than 2.5 minutes. This finding is consistent with the Company’s own results, which defined the optimized RFA procedure as a 45-minute treatment for tumors with a diameter of 3 centimeters. Thus, the NIH analysis lends support to the hypothesis underpinning the OPTIMA Study.

On August 27, 2019, the Company announced that a study from a single site in China titled “Thermosensitive liposomal doxorubicin plus radiofrequency ablation increased tumor destruction and improved survival in patients with medium and large hepatocellular carcinoma: A randomized, double-blinded, dummy-controlled clinical trial in a single center” has been published in theJournal of Cancer Research and Therapeutics.These data were generated as part of the Phase III HEAT (Hepatocellular Carcinoma Study of RFA and ThermoDox^®) Study sponsored by Celsion Corporation. The data from this single site at the Peking University Cancer Hospital and Institute in Beijing show an overall survival (OS) improvement of 22.5 months in patients with 3-7 cm unresectable hepatocellular carcinoma (HCC) tumors receiving combined radiofrequency ablation (RFA) and ThermoDox^®, compared with the use of RFA alone.

In this study, patients received 50 mg/m² of ThermoDox^® or placebo, plus RFA for 45 minutes or longer. Patients were followed for 11 to 80 months (average: 49.1 ± 24.8 months), with 18 of 22 patients completing the study. The mean OS for the ThermoDox^® plus RFA group was 68.5 ± 7.2 months, which was significantly greater than the placebo plus RFA group (46.0 ± 10.6 months, pValue = 0.045). At the end of the follow-up period, the percentage of patients alive after 1, 3 and 5 years were as follows:

		ThermoDox + RFA				RFA Alone
% of patients alive at 1 year			90.0	%			87.5	%
% of patients alive at 3 years			90.0	%			50.0	%
% of patients alive at 5 years			77.1	%			37.5	%

The publication can be found in theJournal of Cancer Research and Therapeutics | Year: 2019 | Volume: 15 | Issue: 4 | Page 773 – 783. The authors are Yang W, Lee JC, Chen MH, Zhang ZY, Bai XM, Yin SS, et al. from the Departments of Ultrasound and Radiology, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Peking University Cancer Hospital and Institute in Beijing. Professor Min-Hua Chen was a principal investigator in Celsion’s Phase III HEAT Study, from which these data are derived, and is also a principal investigator in the Company’s ongoing Phase III OPTIMA Study for the treatment of primary liver cancer with ThermoDox^®plus standardized RFA.

The HEAT Study. On January 31, 2013, we announced that the HEAT Study, ThermoDox® in combination with RFA, did not meet the primary endpoint, PFS, in the Phase III clinical trial enrolling 701 patients with primary liver cancer. This determination was made after conferring with the HEAT Study independent DMC, that the HEAT Study did not meet the goal of demonstrating a clinically meaningful improvement in progression free survival. In the trial, ThermoDox® was well-tolerated with no unexpected serious adverse events. Following the announcement of the HEAT Study results, we continued to follow patients for OS, the secondary endpoint of the HEAT Study. We have conducted a comprehensive analysis of the data from the HEAT Study to assess the future strategic value and development strategy for ThermoDox®.

Acquisition of EGEN Assets

On June 20, 2014, we completed the acquisition of substantially all of the assets of EGEN, which has changed its company name to EGWU, Inc. after the closing of the acquisition, pursuant to an Asset Purchase Agreement dated as of June 6, 2014, by and between us and EGEN, or the Asset Purchase Agreement. We acquired all of EGEN’s right, title and interest in and to substantially all of the assets of EGEN, including cash and cash equivalents, patents, trademarks and other intellectual property rights, clinical data, certain contracts, licenses and permits, equipment, furniture, office equipment, furnishings, supplies and other tangible personal property. In addition, CLSN Laboratories assumed certain specified liabilities of EGEN, including the liabilities arising out of the acquired contracts and other assets relating to periods after the closing date.

At the time of the acquisition, the total purchase price for the asset acquisition was up to $44.4 million, including potential future earnout payments of up to $30.4 million contingent upon achievement of certain earnout milestones set forth in the Asset Purchase Agreement. We paid approximately $3.0 million in cash after the expense adjustment and issued 241,590 shares of our common stock to EGEN. The shares of common stock were issued in a private transaction exempt from registration under the Securities Act, pursuant to Section 4 (2) thereof.

On March 28, 2019, the Company entered into an amendment to the Asset Purchase Agreement, or the Amended Asset Purchase Agreement) with EGWU, Inc. Pursuant to the Amended Asset Purchase Agreement, payment of the earnout milestone liability related to the Ovarian Cancer Indication of $12.4 million has been modified. The Company has the option to make the payment as follows:

	a)	$7.0 million in cash within 10 business days of achieving the milestone; or
	●
	b)	$12.4 million in cash, common stock of the descrCompany, or a combination of either, within one year of achieving the milestone.

The Company provided EGWU, Inc. 200,000 warrants to purchase common stock at a strike price of $0.01 per warrant share as consideration for entering into this amended agreement. The warrant shares have no expiration and were fair valued at $2.00 using the closing price of our common stock on the date of issuance offset by the exercise price and were recorded as a non-cash expense in the income statement and classified as equity on the balance sheet.

GEN-1

GEN-1 is a DNA-based immunotherapeutic product candidate for the localized treatment of ovarian cancer by intraperitoneally administering an Interleukin-12, or IL-12,) plasmid formulated with our proprietary TheraPlas delivery system. In this DNA-based approach, the immunotherapy is combined with a standard chemotherapy drug, which can potentially achieve better clinical outcomes than with chemotherapy alone. We believe that increases in IL-12 concentrations at tumor sites for several days after a single administration could create a potent immune environment against tumor activity and that a direct killing of the tumor with concomitant use of cytotoxic chemotherapy could result in a more robust and durable antitumor response than chemotherapy alone. We believe the rationale for local therapy with GEN-1 is based on the following.

	●	Loco-regional production of the potent cytokine IL-12 avoids toxicities and poor pharmacokinetics associated with systemic delivery of recombinant IL-12;
	●	Persistent local delivery of IL-12 lasts up to one week and dosing can be repeated; and
	●	Ideal for long-term maintenance therapy.

OVATION Study

In February 2015, we announced that the FDA accepted, without objection, the Phase Ib dose-escalation clinical trial of GEN-1 in combination with the standard of care in neo-adjuvant ovarian cancer, or the OVATION Study. On September 30, 2015, we announced enrollment of the first patient in the OVATION Study. The OVATION Study was designed (i) to identify a safe, tolerable and potentially therapeutically active dose of GEN-1 by recruiting and maximizing an immune response and (ii) to enroll three to six patients per dose level to evaluate safety and efficacy and attempt to define an optimal dose for a follow-on Phase II study. In addition, the OVATION Study establishes a unique opportunity to assess how cytokine-based compounds such as GEN-1 directly affect ovarian cancer cells and the tumor microenvironment in newly diagnosed patients. The study was designed to characterize the nature of the immune response triggered by GEN-1 at various levels of the patients’ immune system, including:

We initiated the OVATION Study at four clinical sites at the University of Alabama at Birmingham, Oklahoma University Medical Center, Washington University in St. Louis and the Medical College of Wisconsin. During 2016 and 2017, we announced data from the first fourteen patients in the OVATION Study who completed treatment. On October 3, 2017 and again on March 2, 2109, we announced final clinical and translational research data from the OVATION Study, a Phase Ib dose escalating clinical trial combining GEN-1 with the standard of care for the treatment of newly-diagnosed patients with advanced Stage III/IV ovarian cancer who will undergo neoadjuvant chemotherapy followed by interval debulking surgery.

We reported positive clinical data from the first fourteen patients who have completed treatment in the OVATION Study. GEN-1 plus standard chemotherapy produced positive clinical results, with no dose limiting toxicities and positive dose dependent efficacy signals which correlate well with positive surgical outcomes. The OVATION Study evaluated escalating doses of GEN-1 (36 mg/m², 47 mg/m², 61 mg/m² and 79 mg/m²) administered intraperitoneally in combination with three cycles of neoadjuvant chemotherapy prior to interval debulking surgery, followed by three cycles of NAC in the treatment of newly diagnosed patients with Stage III/IV ovarian cancer.

In this Phase IB dose-escalation study, the 14 patients who were evaluable for response demonstrated median PFS of 21 months in patients treated per protocol and 17.1 months for the intent-to-treat population (n=18) for all dose cohorts, including three patients who dropped out of the study after 13 days or less, and two patients who did not receive full NAC and GEN-1 cycles. In addition, 100% of patients administered NAC plus the two higher doses of GEN-1 experienced an objective tumor response (defined as a partial or complete response) compared to only 60% of patients given the two lower doses. Pathological changes were assessed as part of the study, with the density of markers measured in tissue sections assessed via immunohistochemistry staining. Dose-limiting toxicity was not reached in the OVATION I Study.

OVATION 2 Study

On November 13, 2017, the Company filed its Phase I/II clinical trial protocol with the U.S. Food and Drug Administration for GEN-1 for the localized treatment of ovarian cancer. The protocol is designed with a single dose escalation phase to 100 mg/m² to identify a safe and tolerable dose of GEN-1 while maximizing an immune response. The Phase I portion of the study will be followed by a continuation at the selected dose in 130 patients randomized Phase II study. On November 5, 2019, the Company announced that the independent Data Safety Monitoring Board (DSMB) completed its safety review of data from the first eight patients enrolled in the ongoing Phase I/II OVATION 2 Study.  Based on the DSMB's recommendation, the study will continue as planned and the Company will proceed with completing enrollment in the Phase I portion of the trial. 

In the OVATION 2 Study, patients in the GEN-1 treatment arm will receive GEN-1 plus chemotherapy pre- and post-interval debulking surgery. The OVATION 2 Study will include up to 130 patients with Stage III/IV ovarian cancer, with 12 to 15 patients in the Phase I portion and up to 118 patients in Phase II. The study is powered to show a 33% improvement in the primary endpoint, PFS, when comparing GEN-1 with neoadjuvant + adjuvant chemotherapy versus neoadjuvant + adjuvant chemotherapy alone. The PFS primary analysis will be conducted after at least 80 events have been observed or after all patients have been followed for at least 16 months, whichever is later.

Developed with extensive input from the Company's Medical Advisory Board, the OVATION 2 Study builds on promising clinical and translational research data from the Phase IB dose-escalation OVATION I Study, in which enrolled patients received escalating weekly doses of GEN-1 up to 79 mg/m² for a total of eight treatments in combination with NACT, followed by IDS. In addition to exploring a higher dose of GEN-1 in the OVATION 2 study, patients will continue to receive GEN-1 after their IDS in combination with adjuvant chemotherapy.

The latest DSMB review of GEN-1 at 100 mg/m² has confirmed that there were no dose limiting toxicities detected in any of the five patients dosed with GEN-1 and that intraperitoneal administration is well tolerated even when given with standard NACT. “Of the eight patients treated in the Phase I portion of the OVATION 2 Study, five patients were treated with GEN-1 plus NACT and three patients were treated with NACT only.

Because of the risks and uncertainties discussed in this Annual Report on Form 10-K, among others, we are unable to estimate the duration and completion costs of our research and development projects or when, if ever, and to what extent we will receive cash inflows from the commercialization and sale of a product. Our inability to complete any of our research and development activities, preclinical studies or clinical trials in a timely manner or our failure to enter into collaborative agreements when appropriate could significantly increase our capital requirements and could adversely impact our liquidity. While our estimated future capital requirements are uncertain and could increase or decrease as a result of many factors, including the extent to which we choose to advance our research, development activities, preclinical studies and clinical trials, or if we are in a position to pursue manufacturing or commercialization activities, we will need significant additional capital to develop our product candidates through development and clinical trials, obtain regulatory approvals and manufacture and commercialize approved products, if any. We do not know whether we will be able to access additional capital when needed or on terms favorable to us or our stockholders. Our inability to raise additional capital, or to do so on terms reasonably acceptable to us, would jeopardize the future success of our business.

TheraPlas Technology Platform. TheraPlas is a technology platform for the delivery of DNA and messenger RNA, or mRNA, therapeutics via synthetic non-viral carriers and is capable of providing cell transfection for double-stranded DNA plasmids and large therapeutic RNA segments such as mRNA. There are two components of the TheraPlas system, a plasmid DNA or mRNA payload encoding a therapeutic protein and a delivery system. The delivery system is designed to protect the DNA/RNA from degradation and promote trafficking into cells and through intracellular compartments. We designed the delivery system of TheraPlas by chemically modifying the low molecular weight polymer to improve its gene transfer activity without increasing toxicity. We believe TheraPlas is a viable alternative to current approaches to gene delivery due to several distinguishing characteristics, including enhanced molecular versatility that allows for complex modifications to improve activity and safety.

On August 8, 2016, we signed the GEN-1 Agreement with Hisun to pursue an expanded partnership for the technology transfer relating to the clinical and commercial manufacture and supply of GEN-1, Our proprietary gene mediated, IL-12 immunotherapy, for the China territory, with the option to expand into other countries in the rest of the world after all necessary regulatory approvals are obtained. The GEN-1 Agreement will help to support supply for both ongoing and planned clinical studies in the U.S. and for potential future studies of GEN-1 in China. We are currently evaluating GEN-1 in first line ovarian cancer patients.

In June 2012, we and Hisun signed a long-term commercial supply agreement for the production of ThermoDox®. Hisun is one the largest manufacturers of chemotherapy agents globally, including doxorubicin. In July 2013, the ThermoDox® collaboration was expanded to focus on next generation liposomal formulation development with the goal of creating safer, more efficacious versions of marketed cancer chemotherapeutics. During 2015, Hisun successfully completed the manufacture of three registration batches for ThermoDox® and has obtained regulatory approvals to supply ThermoDox® to participating clinical trial sites in all of the countries of South East Asia and North America, as well as to the European Union countries allowing for early access to ThermoDox®. The future manufacturing of clinical and commercial supplies by Hisun will result in a cost structure allowing us to profitably access all global markets, including third world countries, and help accelerate the Company’s product development program in China for ThermoDox® in primary liver cancer and other approved indications.

Corporate Information

We were founded in 1982 and is a Delaware corporation. Our principal executive offices are located at 997 Lenox Drive, Suite 100, Lawrenceville, NJ 08648. Our telephone number is (609) 896-9100. Our website is www.celsion.com. The information contained on or that can be accessed through our website is not incorporated by reference into this prospectus, and you should not consider information on our website to be part of this prospectus or in deciding to purchase our common stock.

The Offering

iptionCommon stock being offered by the selling stockholder		4,500,000 shares
Common stock outstanding		22,002,418 (as of September 30, 2019, excluding the Commitment Shares, as defined below).
Use of proceeds		The selling stockholder will receive all of the proceeds from the sale of the shares offered for sale by it under this prospectus. We will not receive proceeds from the sale of the shares by the selling stockholder. However, we may receive up to $10.0 million in proceeds from the sale of our common stock containedto the selling stockholder under the common stock purchase agreement described below. Any proceeds from the selling stockholder that we receive under the purchase agreement are expected be used for working capital and general corporate purposes.
Nasdaq Symbol		CLSN
Risk Factors		Investing in our registration statement on Form 8-A filed withsecurities involves a high degree of risk. You should carefully review and consider the SEC on May 26, 2000, as amended by“Risk Factors” section of this prospectus for a Form 8-A/A dated February 7, 2008, and any amendments or reports filed for the purposediscussion of updating such description. factors to consider before deciding to invest in shares of our common stock.

 

Any The number of shares of our common stock outstanding is based on an aggregate of 22,002,418 shares of our common stock outstanding as ofSeptember 30, 2019and excludes the 100,000 Commitment Shares as defined below, and also excludes:

●	3,951,142 shares of common stock issuable upon the exercise of outstanding options as ofSeptember 30, 2019, having a weighted average exercise price of$2.56per share;
●	21,750 shares of common stock issuable upon the vesting of common stock awards as of September 30, 2019, having a weighted average grant day fair value of $2.22 per share;
●	626,098 shares of common stock issuable upon the exercise of outstanding warrants as ofSeptember 30, 2019 having a weighted average exercise price of $1.87 per share; and
●	854,507shares of common stock reserved for future issuance pursuant to our existing stock incentive plan.

Common Stock Issued and Issuable to the Selling Stockholder

On October 28, 2019, we entered into a common stock purchase agreement (referred to in this prospectus as the “Purchase Agreement”), with Aspire Capital Fund, LLC, an Illinois limited liability company (referred to in this prospectus as “Aspire Capital” or the “selling stockholder”), which provides that, upon the terms and subject to the conditions and limitations set forth therein, Aspire Capital is committed to purchase up to an aggregate of $10.0 million of our shares of common stock over the approximately 24-month term of the Purchase Agreement. In consideration for entering into the Purchase Agreement, concurrently with the execution of the Purchase Agreement, we issued to Aspire Capital 100,000 shares of our common stock as a commitment fee (referred to in this prospectus as the “Commitment Shares”). Concurrently with entering into the Purchase Agreement, we also entered into a registration rights agreement with Aspire Capital (referred to in this prospectus as the “Registration Rights Agreement”), in which we agreed to file one or more registration statements, including the registration statement containedof which this prospectus is a part, as permissible and necessary to register under the Securities Act of 1933, as amended, or the Securities Act, the sale of the shares of our common stock that have been and may be issued to Aspire Capital under the Purchase Agreement.

As of October 28, 2019, there were 22,655,818 shares of our common stock outstanding excluding the 4,500,000 shares offered that have been issued or may be issuable to Aspire Capital pursuant to the Purchase Agreement. If all of such shares of our common stock offered hereby were issued and outstanding as of the date hereof, such shares would represent 19.99% of the total common stock outstanding as of the date hereof. The number of shares of our common stock ultimately offered for sale by Aspire Capital is dependent upon the number of shares purchased by Aspire Capital under the Purchase Agreement.

Pursuant to the Purchase Agreement and the Registration Rights Agreement, we are registering 4,500,000 shares of our common stock under the Securities Act, which includes the Commitment Shares that have already been issued to Aspire Capital and 4,400,000 shares of common stock which we may issue to Aspire Capital after this registration statement is declared effective under the Securities Act. All 4,500,000 shares of common stock are being offered pursuant to this prospectus.

After the Securities and Exchange Commission has declared effective the registration statement of which this prospectus is a part, on any trading day on which the closing sale price of our common stock exceeds $0.25, we have the right, in any document incorporatedour sole discretion, to present Aspire Capital with a purchase notice (each, a “Purchase Notice”), directing Aspire Capital (as principal) to purchase up to 100,000 shares of our common stock per trading day, up to $10.0 million of our common stock in the aggregate at a per share price (the “Purchase Price”) calculated by reference hereinto the prevailing market price of our common stock (as more specifically described below).

In addition, on any date on which we submit a Purchase Notice for 100,000 shares to Aspire Capital, we also have the right, in our sole discretion, to present Aspire Capital with a volume-weighted average price purchase notice (each, a “VWAP Purchase Notice”) directing Aspire Capital to purchase an amount of stock equal to up to 30% of the aggregate shares of the Company’s common stock traded on Nasdaq on the next trading day (the “VWAP Purchase Date”), subject to a maximum number of shares we may determine (the “VWAP Purchase Share Volume Maximum”) and a minimum trading price (the “VWAP Minimum Price Threshold”) (as more specifically described below). The purchase price per Purchase Share pursuant to such VWAP Purchase Notice (the “VWAP Purchase Price”) is calculated by reference to the prevailing market price of our common stock (as more specifically described below). The respective prices and share numbers in the preceding paragraphs shall be deemedappropriately adjusted for any reorganization, recapitalization, non-cash dividend, stock split, reverse stock split or other similar transaction.

The Purchase Agreement provides that the Company and Aspire Capital shall not effect any sales under the Purchase Agreement on any purchase date where the closing sale price of our common stock is less than $0.25 per share (the “Floor Price”). There are no trading volume requirements or restrictions under the Purchase Agreement, and we will control the timing and amount of any sales of our common stock to Aspire Capital. Aspire Capital has no right to require any sales by us, but is obligated to make purchases from us as we direct in accordance with the Purchase Agreement. There are no limitations on use of proceeds, financial or business covenants, restrictions on future fundings, rights of first refusal, participation rights, penalties or liquidated damages in the Purchase Agreement. Aspire Capital may not assign its rights or obligations under the Purchase Agreement. The Purchase Agreement may be modifiedterminated by us at any time, at our discretion, without any penalty or superseded for purposes of this prospectuscost to us.

Risk Factors

You should carefully consider the extent that a statementfollowing information about risks, together with the other information contained in this prospectus, before making an investment in our common stock. If any of the circumstances or events described below actually arises or occurs, our business, results of operations, cash flows and financial condition could be harmed. In any prospectus modifiessuch case, the market price of our common stock could decline, and you may lose all or supersedes such statement. Any statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of your investment.

Risks Related to This Offering

We will need to raise substantial additional capital in the future to fund our operations and we may be unable to raise such funds when needed and on acceptable terms.

The extent to which we utilize the Purchase Agreement with Aspire Capital as a source of funding will depend on a number of factors, including the prevailing market price of our common stock, the volume of trading in our common stock and the extent to which we are able to secure funds from other sources. The number of shares that we may sell to Aspire Capital under the Purchase Agreement on any given day and during the term of the agreement is limited. See “The Aspire Capital Transaction” section of this prospectus.prospectus for additional information. Additionally, we and Aspire Capital may not effect any sales of shares of our common stock under the Purchase Agreement during the continuance of an event of default or on any trading day that the closing sale price of our common stock is less than $0.25 per share. Even if we are able to access the full $10.0 million under the Purchase Agreement, we will still need additional capital to fully implement our business, operating and development plans.

 

The sale of our common stock to Aspire Capital may cause substantial dilution to our existing stockholders and the sale of the shares of common stock acquired by Aspire Capital could cause the price of our common stock to decline.

We also incorporateare registering for sale the Commitment Shares that we have issued and 4,400,000 shares that we may sell to Aspire Capital under the Purchase Agreement. It is anticipated that shares registered in this offering will be sold over a period of up to approximately 24 months from the date of this prospectus. The number of shares ultimately offered for sale by reference any future filings, other than current reports furnishedAspire Capital under Item 2.02this prospectus is dependent upon the number of shares we elect to sell to Aspire Capital under the Purchase Agreement. Depending on a variety of factors, including market liquidity of our common stock, the sale of shares under the Purchase Agreement may cause the trading price of our common stock to decline.

Aspire Capital may ultimately purchase all, some or Item 7.01 none of Form 8-K and exhibits filed on such formthe $10.0 million of common stock that, are related to such items, madetogether with the SECCommitment Shares, is the subject of this prospectus. Aspire Capital may sell all, some or none of our shares that it holds or comes to hold under the Purchase Agreement. Sales by Aspire Capital of shares acquired pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act, in each case, other than those documents or the portions of those documents deemed to be furnished and not filed in accordance with SEC rules, until the offering of the securitiesPurchase Agreement under the registration statement, of which this prospectus formsis a part, is terminated or completed. Informationmay result in such future filings updates and supplementsdilution to the information providedinterests of other holders of our common stock. The sale of a substantial number of shares of our common stock by Aspire Capital in this prospectus. Any statements in anyoffering, or anticipation of such future filings will be deemedsales, could cause the trading price of our common stock to modify and supersede any information in any document we previously filed with the SEC that is incorporateddecline or deemedmake it more difficult for us to be incorporated herein by reference to the extent that statementssell equity or equity-related securities in the later filed document modify or replace such earlier statements.

Because we are incorporating by reference future filings with the SEC, this prospectus is continually updatedat a time and later information filed with the SEC may update and supersede some of the information included or incorporated by reference in this prospectus. This means that you must look at all of the SEC filingsa price that we incorporate by referencemight otherwise desire. However, we have the right under the Purchase Agreement to determine if anycontrol the timing and amount of sales of our shares to Aspire Capital, and the statements in this prospectus or in any document previously incorporated by reference have been modified or superseded.

We will provide without charge to each person, including any beneficial owners, to whom this prospectus is delivered, upon his or her written or oral request, a copy of any or all reports or documents referred to above which have been orPurchase Agreement may be incorporatedterminated by reference into this prospectus but not delivered with this prospectus, excluding exhibits to those reports or documents unless they are specifically incorporated by reference into those documents. You may request a copy of these documents by writing or telephoning us at the following address.any time at our discretion without any penalty or cost to us.

Celsion Corporation

997 Lenox Drive, Suite 100

Lawrenceville, New Jersey 08648

(609) 896-9100

Attention: Jeffrey W. Church

Senior Vice President, Chief Financial Officer and Corporate Secretary

SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

Certain statements contained or incorporated by reference in this prospectus, in any applicable prospectus and in any related free writing prospectus constitute forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 and releases issued by the SEC and within the meaning of Section 27A of the Securities Act of 1933, as amended (the Securities Act), and Section 21E of the Exchange Act. From time to time, we may publish forward-looking statements relating to such matters as anticipated financial performance, business prospects, technological developments, product pipelines, clinical trials and research and development activities, the adequacy of capital reserves and anticipated operating results and cash expenditures, current and potential collaborations, strategic alternatives and other aspects of our present and future business operations and similar matters that also constitute such forward-looking statements. These statements involve known and unknown risks, uncertainties and other factors that may cause our or our industry’s actual results, levels of activity, performance or achievements to be materially different from any future results, levels of activity, performance or achievements expressed or implied by such forward-looking statements. Such statements include, without limitation:

In some cases, you can identify forward-looking statements by terminology such as “expect,“expect,” “anticipate,” “estimate,” “continue,” “plan,” “believe,” “could,” “intend,” “predict,” “may,” “should,” “will,” “would” and words of similar import regarding our expectations. Forward-looking statements are only predictions. Actual events or results may differ materially. Although we believe that our expectations are based on reasonable assumptions within the bounds of our knowledge of our industry, business and operations, we cannot guarantee that actual results will not differ materially from our expectations. In evaluating such forward-looking statements, you should specifically consider various factors, including the risks outlined under “Risk Factors” contained in this prospectus and any related free writing prospectus, and in our most recent Annual Report on Form 10-K and our most recent filed Quarterly Reports on Form 10-Q, as well as any amendments thereto reflected in subsequent filings with the SEC. The discussion of risks and uncertainties set forth in those filings is not necessarily a complete or exhaustive list of all risks facing us at any particular point in time. We operate in a highly competitive, highly regulated and rapidly changing environment, and our business is in a state of evolution. Therefore, it is likely that new risks will emerge and the nature and elements of existing risks will change. It is not possible for management to predict all such risk factors or changes therein or to assess either the impact of all such risk factors on our business or the extent to which any individual risk factor, combination of factors or new or altered factors may cause results to differ materially from those contained in any forward-looking statement. Forward-looking statements represent our estimates and assumptions only as of the date such forward-looking statements are made. You should carefully read this prospectus supplement and any related free writing prospectus, together with the information incorporated herein or therein by reference as described under the section titled “Information Incorporated By Reference,” and with the understanding that our actual future results may materially differ from what we expect.

Except as required by law, forward-looking statements speakspeak only as of the date they are made, and we assume no obligation to update any forward-looking statements publicly, or to update the reasons why actual results could differ materially from those anticipated in any forward-looking statements, even if new information becomes available.

PROSPECTUS SUMMARY

The following summary highlights information contained elsewhere or incorporated by reference in this prospectus. This summary does not contain all of the information you should consider before investing in the securities. Before making an investment decision, you should read the entire prospectus carefully, including the matters discussed under the heading “Risk Factors” in this prospectus and under similar headings in other documents that are incorporated by reference into this prospectus.

Overview

Celsion is a fully-integrated development stage oncology drug company focused on advancing a portfolio of innovative cancer treatments, including directed chemotherapies, DNA-mediated immunotherapy and RNA based therapies. Our lead product candidate is ThermoDox^®, a proprietary heat-activated liposomal encapsulation of doxorubicin, currently in a Phase III clinical trial for the treatment of primary liver cancer (the “OPTIMA Study”), and a Phase II clinical trial for the treatment of recurrent chest wall breast cancer (the “DIGNITY Study”). Second in our pipeline is GEN-1, a DNA-mediated immunotherapy for the localized treatment of ovarian and brain cancers. We have two platform technologies providing the basis for the future development of a range of therapeutics for difficult-to-treat forms of cancer including: Lysolipid Thermally Sensitive Liposomes, a heat sensitive liposomal based dosage form that targets disease with known therapeutics in the presence of mild heat and TheraPlas, a novel nucleic acid-based treatment for local transfection of therapeutic plasmids. With these technologies we are working to develop and commercialize more efficient, effective and targeted oncology therapies that maximize efficacy while minimizing side-effects common to cancer treatments.Aspire Capital Transaction

ThermoDox®

ThermoDox^® is being evaluated in a Phase III clinical trial for primary liver cancer, which we call the OPTIMA Study, which was initiated in 2014, and a Phase II clinical trial for recurrent chest wall breast cancer, which we call the DIGNITY Study. ThermoDox^® is a liposomal encapsulation of doxorubicin, an approved and frequently used oncology drug for the treatment of a wide range of cancers. Localized heat at hyperthermia temperatures (greater than 40° Celsius) releases the encapsulated doxorubicin from the liposome enabling high concentrations of doxorubicin to be deposited preferentially in and around the targeted tumor.

The OPTIMA Study.The OPTIMA Study represents an evaluation of ThermoDox^® in combination with a first line therapy, radiofrequency ablation (“RFA”), for newly diagnosed, intermediate stage HCC patients. HCC incidence globally is approximately 850,000 new cases per year and is the third largest cancer indication globally. Approximately 30% of newly diagnosed patients can be addressed with RFA alone.General

On February 24, 2014,October 28, 2019, we announcedentered into the Purchase Agreement which provides that, upon the United States Foodterms and Drug Administration (the “FDA”), after its customary 30-day review period, provided clearance forsubject to the OPTIMA Study, whichconditions and limitations set forth therein, Aspire Capital is a pivotal, double-blind, placebo-controlled Phase III trialcommitted to purchase up to an aggregate of ThermoDox^®, in combination with standardized RFA, for$10.0 million of our shares of common stock over the treatment of primary liver cancer. The trial designterm of the OPTIMA Study is based onPurchase Agreement. In consideration for entering into the comprehensive analysis of data from an earlier clinical trial calledPurchase Agreement, concurrently with the HEAT Study, which is described below. The OPTIMA Study is supported by a hypothesis developed from an overall survival analysis of a large subgroup of patients from the HEAT Study.

We initiated the OPTIMA Study in the first half of 2014. The OPTIMA Study was designed with extensive input from globally recognized hepatocellular carcinoma (“HCC”) researchers and expert clinicians and after receiving formal written consultation from the FDA. The OPTIMA Study is expected to enroll up to 550 patients globally at up to 65 sites in the United States, Canada, Europe Union, China and other countries in the Asia-Pacific region, and will evaluate ThermoDox^® in combination with standardized RFA, which will require a minimum of 45 minutes across all investigators and clinical sites for treating lesions three to seven centimeters, versus standardized RFA alone. The primary endpoint for this clinical trial is overall survival (“OS”), and the secondary endpoints are progression free survival and safety. The statistical plan calls for two interim efficacy analyses by an independent Data Monitoring Committee (“DMC”).

On December 16, 2015, we announced that we had received the clinical trial application approval from the China Food and Drug Administration (the “CFDA”) to conduct the OPTIMA Study in China. This clinical trial application approval will allow Celsion to enroll patients at up to 20 clinical sites in China. On April 26, 2016, we announced that the first patient in China had been enrolled in the OPTIMA Study. Results from the OPTIMA Study, if successful, will provide the basis for a global registration filing and marketing approval.

On August 7, 2017, the Company announced that the independent Data Monitoring Committee (DMC) for the Company's OPTIMA Study completed a regularly scheduled reviewexecution of the first 50% of patients enrolled inPurchase Agreement, we issued to Aspire Capital the trial and has unanimously recommended thatCommitment Shares. Concurrently with entering into the OPTIMA Study continue according to protocol to its final data readout. The DMC reviewed study data at regular intervals, with the primary responsibilities of ensuring the safety of all patients enrolled in the study, the quality of the data collected, and the continued scientific validity of the study design. As part of its review of the first 275 patients, the DMC monitored a quality matrix relating to the total clinical data set, confirming the timely collection of data, that all data are current as well as other data collection and quality criteria.

The Company hosted an Investigators Meeting with physicians in South East Asia and key opinion leaders on July 22-23, 2017 in Bangkok, Thailand. A second Investigators Meeting was held on September 23, 2017 with physicians in China. The Company has initiated approximately 70 clinical sites in 14 countries with plans to activate up to 8 additional clinical trial sites in China or Vietnam by the end of 2017. In addition, the Company announced that patient enrollment in the 550 patient Phase III global study has reached over 67%. Based on current enrollment rates, the Company expects to complete enrollment of the study by mid-2018.

Post-hoc data analysis from the Company’s earlier Phase III HEAT Study suggest that ThermoDox^® may substantially improve OS, when compared to the control group, in patients if their lesions undergo a 45 minute RFA procedure standardized for a lesion greater than 3 cm in diameter. Data from nine OS sweeps have been conducted since the top line progression free survival (“PFS”) data from the HEAT Study were announced in January 2013, with each data set demonstrating substantial improvement in clinical benefit over the control group with statistical significance. On August 15, 2016, the Company announced updated results from its final retrospective OS analysis of the data from the HEAT Study. These results demonstrated that in a large, well bounded, subgroup of patients with a single lesion (n=285, 41% of the HEAT Study patients), treatment with a combination of ThermoDox^® and optimized RFA provided an average 54% risk improvement in OS compared to optimized RFA alone. The Hazard Ratio (“HR”) at this analysis is 0.65 (95% CI 0.45 - 0.94) with a p-value of 0.02. Median OS for the ThermoDox^® group has been reached which translates into a two year survival benefit over the optimized RFA group (projected to be greater than 80 months for the ThermoDox^® plus optimized RFA group compared to less than 60 months projection for the optimized RFA only group). Additional findings from this most recent analysis specific to the Chinese patient cohort of 223 patients are summarized below:

While this information should be viewed with caution since it is based on a retrospective analysis of a subgroup,Purchase Agreement, we also conducted additional analyses that further strengthenentered into the evidence forRegistration Rights Agreement, in which we agreed to file one or more registration statements as permissible and necessary to register under the HEAT Study sub-group. We commissioned an independent computational model atSecurities Act, the Universitysale of South Carolina Medical School. The results indicate that longer RFA heating times correlate with significant increases in doxorubicin concentration around the RFA treated tissue. In addition, we conducted a prospective preclinical study in 22 pigs using two different manufacturers of RFA and human equivalent doses of ThermoDox^® that clearly support the relationship between increased heating duration and doxorubicin concentrations.

On November 29, 2016, the Company announced the results of an independent analysis conducted by the National Institutes of Health (the “NIH”) from the HEAT Study which reaffirmed the correlation between increased RFA burn time per tumor volume and improvements in overall survival. The NIH analysis, which sought to evaluate the correlation between RFA burn time per tumor volume (min/ml) and clinical outcome, concluded that increased burn time per tumor volume significantly improved overall survival in patients treated with RFA plus ThermoDox^® compared to patients treated with RFA alone. For all patients with single lesions treated with RFA plus ThermoDox^®:

The HEAT Study. On January 31, 2013, the Company announced that the HEAT Study, ThermoDox^® in combination with RFA, did not meet the primary endpoint, PFS, of a Phase III clinical trial enrolling 701 patients with primary liver cancer. This determination was made after conferring with the HEAT Study independent DMC, that the HEAT Study did not meet the goal of demonstrating a clinically meaningful improvement in progression free survival. In the trial, ThermoDox^® was well-tolerated with no unexpected serious adverse events. Following the announcement of the HEAT Study results, we continued to follow patients for OS, the secondary endpoint of the HEAT Study. We have conducted a comprehensive analysis of the data from the HEAT Study to assess the future strategic value and development strategy for ThermoDox^®.

The DIGNITY Study.On December 14, 2015, we announced final data from our ongoing DIGNITY study, which is an open-label, dose-escalating Phase II trial of ThermoDox^® in patients with recurrent chest wall (“RCW”) breast cancer. The DIGNITY Study was designed to establish a safe therapeutic dose in Phase I, and to demonstrate local control in Phase II, including complete and partial responses, and stable disease as its primary endpoint. The DIGNITY Study was also designed to evaluate kinetics in ThermoDox^® produced from more than one manufacturing site. Of the 29 patients enrolled and treated, 21 patients were eligible for evaluation of efficacy. Approximately 62% of evaluable patients experienced a local response, including six complete responses and seven partial responses.

Acquisition of EGEN Assets

On June 20, 2014, we completed the acquisition of substantially all of the assets of Egen, Inc., an Alabama corporation, which has changed its company name to EGWU, Inc. after the closing of the acquisition (“EGEN”), pursuant to an asset purchase agreement dated as of June 6, 2014, by and between EGEN and Celsion (the “Asset Purchase Agreement”). We acquired all of EGEN’s right, title and interest in and to substantially all of the assets of EGEN, including cash and cash equivalents, patents, trademarks and other intellectual property rights, clinical data, certain contracts, licenses and permits, equipment, furniture, office equipment, furnishings, supplies and other tangible personal property. In addition, CLSN Laboratories assumed certain specified liabilities of EGEN, including the liabilities arising out of the acquired contracts and other assets relating to periods after the closing date.

The total purchase price for the asset acquisition is up to $44.4 million, including potential future earnout payments of up to $30.4 million contingent upon achievement of certain earnout milestones set forth in the Asset Purchase Agreement. At the closing, we paid approximately $3.0 million in cash after the expense adjustment and issued 193,728 shares of our common stock that have been and may be issued to EGEN. The shares of common stock were issued in a private transaction exempt from registrationAspire Capital under the Securities Act, pursuant to Section 4(2) thereof. In addition, 47,862 shares of common stock were held back by us at the closing and are issuable to EGEN pending satisfactory resolution of any post-closing adjustments for expenses or in relation to EGEN’s indemnification obligations under the Asset Purchase Agreement. These shares were issued on June 16, 2017.

The earnout paymentsAs of up to $30.4 million will become payable, in cash,October 28, 2019, there were 22,655,818 shares of our common stock or a combination thereof, atoutstanding (168,672 shares held by affiliates) excluding the 4,500,000 shares offered that may be issuable to Aspire Capital pursuant to the Purchase Agreement. If all of such 4,500,000 shares of our option upon achievement of three major milestone eventscommon stock offered hereby were issued and outstanding as follows: 

Our obligations to make the earnout payments will terminate on the seventh anniversary of the closing date. In the acquisition, we purchased GEN-1, a DNA-based immunotherapy for the localized treatment of ovarian and brain cancers, and two platform technologies for the development of treatments for those suffering with difficult-to-treat forms of cancer, novel nucleic acid-based immunotherapies and other anticancer DNA or RNA therapies, including TheraPlas and TheraSilence.

GEN-1

GEN-1 is a DNA-based immunotherapeutic product for the localized treatment of ovarian and brain cancers by intraperitoneally administering an Interleukin-12 (“IL-12”) plasmid formulated with our proprietary TheraPlas delivery system. In this DNA-based approach, the immunotherapy is combined with a standard chemotherapy drug, which can potentially achieve better clinical outcomes than with chemotherapy alone. We believe that increases in IL-12 concentrations at tumor sites for several days after a single administration could create a potent immune environment against tumor activity and that a direct killingdate hereof, such shares would represent 19.99% of the tumor with concomitant use of cytotoxic chemotherapy could result in a more robust and durable antitumor response than chemotherapy alone. We believe the rationale for local therapy with GEN-1 are based on the following.

We believe the rationale for local therapy with GEN-1 are based on the following:

GEN-1 OVATION Study.In February 2015, we announced that the FDA accepted, without objection, the Phase I dose-escalation clinical trial of GEN-1 in combination with the standard of care in neo-adjuvant ovarian cancer (the “OVATION Study”). On September 30, 2015, we announced enrollmenttotal common stock outstanding or 20.00% of the first patient in the OVATION Study. The OVATION Study will seek to identify a safe, tolerable and potentially therapeutically active dose of GEN-1 by recruiting and maximizing an immune response and is designed to enroll three to six patients per dose level and will evaluate safety and efficacy and attempt to define an optimal dose for a follow-on Phase I/II study combining GEN-1 with Avastin^® and Doxil^®. In addition, the OVATION Study establishes a unique opportunity to assess how cytokine-based compounds such as GEN-1, directly affect ovarian cancer cells and the tumor microenvironment in newly diagnosed patients. The study is designed to characterize the nature of the immune response triggered by GEN-1 at various levels of the patients’ immune system, including:

We initiated the OVATION Study at four clinical sites at the University of Alabama at Birmingham, Oklahoma University Medical Center, Washington University in St. Louis and the Medical College of Wisconsin. During 2016 and 2017, we announced data from the first fourteen patients in the OVATION Study who completed treatment.

On October 3, 2017, we announced final clinical and translational research data from its OVATION Study, a Phase Ib dose escalating clinical trial combining GEN-1, the Company's DNA-based immunotherapy, with the standard of care for the treatment of newly-diagnosed patients with advanced Stage III/IV ovarian cancer who will undergo neoadjuvant chemotherapy followed by interval debulking surgery.

Key translational research findings from all evaluable patients are consistent with the earlier reports from partial analysis of the data and are summarized below:

Celsion also reported positive clinical data from the first fourteen patients who have completed treatment in the OVATION Study.  GEN-1 plus standard chemotherapy produced positive clinical results, with no dose limiting toxicities and positive dose dependent efficacy signals which correlate well with positive surgical outcomes as summarized below:

The Company also held an Advisory Board Meeting on September 27, 2017 with the clinical investigators and scientific experts including those from Roswell Park Cancer Institute, Vanderbilt University Medical School, and M.D. Anderson Cancer Center to review and finalize clinical, translational research and safety data from the OVATION Study in order to determine the next steps forward for our GEN-1 immunotherapy.  With the endorsement and recommendations from the Advisory Board, the Company expects to file a next phase protocol with FDA by the end of 2017.

GEN-1 Plus Doxil®and Avastin®Trial.On April 29, 2015, we announced the expansion of our ovarian cancer development program to include a Phase I dose escalating trial to evaluate GEN-1 in combination with Avastin^® and Doxil^® in platinum-resistant ovarian cancer patients. This new combination study in platinum-resistant ovarian cancer is supported by three preclinical studies indicating that the combination of GEN-1 with Avastin^® may result in significant clinical benefit with a favorable safety profile.

Specifically:

TheraPlas™Technology Platform.TheraPlas™ is a technology platform for the delivery of DNA and messenger RNA (“mRNA”) therapeutics via synthetic non-viral carriers and is capable of providing cell transfection for double-stranded DNA plasmids and large therapeutic RNA segments such as mRNA. There are two components of the TheraPlas™ system, a plasmid DNA or mRNA payload encoding a therapeutic protein and a delivery system. The delivery system is designed to protect the DNA/RNA from degradation and promote trafficking into cells and through intracellular compartments. We designed the delivery system of TheraPlas™ by chemically modifying the low molecular weight polymer to improve its gene transfer activity without increasing toxicity. We believe TheraPlas™ is a viable alternative to current approaches to gene delivery due to several distinguishing characteristics, including enhanced molecular versatility that allows for complex modifications to improve activity and safety.

Technology Development and Licensing Agreements. Our current efforts and resources are applied on the development and commercialization of cancer drugs including tumor-targeting chemotherapy treatments using focused heat energy in combination with heat-activated drug delivery systems, immunotherapies and RNA-based therapies. To support our research and development, we raised gross proceeds of approximately $127.2 million in equity financings and warrant and option exercises in the years 2010 through 2015. During 2016, we raised gross proceeds of $7.8 million through two registered direct equity financings with several institutional investors. In 2017 thus far, we raised $10.1 million in gross proceeds from a public offering equity financing and $22.0 million from the exercise of warrants to purchase common stock. We had cash and cash equivalents totaling $2.7 million at September 30, 2017. We have one credit facility for a total principle amount of up to $20 million and have drawn down $10 million under this credit facility.

On August 8, 2016, we signed a Technology Transfer, Manufacturing and Commercial Supply Agreement (the “GEN-1 Agreement”) with Hisun to pursue an expanded partnership for the technology transfer relating to the clinical and commercial manufacture and supply of GEN-1, Celsion’s proprietary gene mediated, IL-12 immunotherapy, for the greater China territory, with the option to expand into other countries in the rest of the world after all necessary regulatory approvals are obtained. The GEN-1 Agreement will help to support supply for both ongoing and planned clinical studies in the United States, and for potential future studies of GEN-1 in China. GEN-1 is currently being evaluated by Celsion in first line ovarian cancer patients.

In June 2012, Celsion and Hisun signed a long-term commercial supply agreement for the production of ThermoDox^®. Hisun is one the largest manufacturers of chemotherapy agents globally, including doxorubicin. In July 2013, the ThermoDox^® collaboration was expanded to focus on next generation liposomal formulation development with the goal of creating safer, more efficacious versions of marketed cancer chemotherapeutics. During 2015, Hisun successfully completed the manufacture of three registration batches for ThermoDox^® and has obtained regulatory approvals to supply ThermoDox^® to participating clinical trial sites in all of the countries of South East Asia, Europe and North America, as well as to the European Union countries allowing for early access to ThermoDox^®. The future manufacturing of clinical and commercial supplies by Hisun will result in a cost structure allowing Celsion to profitably access all global markets, including third world countries, and help accelerate the Company’s product development program in China for ThermoDox^® in primary liver cancer and other approved indications.  

Business Strategy and Development Plan

We have not generated and do not expect to generate any revenue from product sales in the next several years, if at all. An element of our business strategy has been to pursue, as resources permit, the research and development of a range of product candidates for a variety of indications. We may also evaluate licensing cancer products from third parties for cancer treatments to expand our current product pipeline. This is intended to allow us to diversify the risks associated with our research and development expenditures. To the extent we are unable to maintain a broad range of product candidates, our dependence on the success of one or a few product candidates would increase and results such as those announced in relation to the HEAT study on January 31, 2013 will have a more significant impact on our financial prospects, financial condition and market value. We may also consider and evaluate strategic alternatives, including investment in, or acquisition of, complementary businesses, technologies or products. As demonstrated by the HEAT Study results, drug research and development is an inherently uncertain process and there is a high risk of failure at every stage prior to approval. The timing and the outcome of clinical results are extremely difficult to predict. The success or failure of any preclinical development and clinical trial can have a disproportionately positive or negative impact on our results of operations, financial condition, prospects and market value.  

Our current business strategy includes the possibility of entering into collaborative arrangements with third parties to complete the development and commercialization of our product candidates. In the event that third parties take over the clinical trial process for one or more of our product candidates, the estimated completion date would largely be under the control of that third party rather than us. We cannot forecast with any degree of certainty which proprietary products or indications, if any, will be subject to future collaborative arrangements, in whole or in part, and how such arrangements would affect our development plan or capital requirements. We may also apply for subsidies, grants or government or agency-sponsored studies that could reduce our development costs.

As of September 30, 2017, we have approximately $2.7 million in cash and cash equivalents. In July 2017, the Company completed a $5 million registered direct equity offering ofnon-affiliate shares of common stock or pre-funded warrants in lieu thereof, and a concurrent private placement of warrants to purchase common stock, with several institutional healthcare investors. In early October 2017, the Company received $17 million in gross proceeds collectively from certain warrant holders exercising warrants to purchase collectively 5.0 million shares of common stock. On October 27, 2017, we entered into an underwriting agreement whereby the Company sold approximately 2.6 million shares of common stock and warrants to purchase approximately 1.3 million shares of common stock for gross proceeds of $6.6 million. The Company has a Controlled Equity Offering^SM Sales Agreement (the “ATM Agreement”) with Cantor Fitzgerald & Co. In connection with the underwritten offering, we have agreed not to sell any additional shares under the Sales Agreement for a period of two months after the closing date of this offering. The Company will be required to obtain additional funding in order to continue the development of its current product candidates within the anticipated time periods, if at all, and to continue to fund operations. The Company has $7.5 million available under a controlled equity offering facility it has with Cantor Fitzgerald & Co. Besides this equity facility, the Company does not have any committed sources of financing at this time, and there is substantial uncertainty whether additional funding will be available when needed on terms that will be acceptable to it, or at all. If the Company would not be able to obtain financing when needed, it could be unable to carry out the business plan and may have to significantly limit its operations and its business and its financial condition and results of operations could be materially harmed. With the current cash on hand and from the gross proceeds of $23.6 million from warrant exercises and the equity offering in October, 2017, the Company believes it has sufficient capital resources to fund its operations well into the second quarter of 2019.

Recent Developments

On October 4, 2017, the Company entered into letter agreements (the “Exercise Agreements”) with the holders of the Series AAA and Series BBB Warrants issued in the July 6, 2017 Common Stock Offering (the “Exercising Holders”). The Exercise Agreements amended the Series AAA Warrants to permit their immediate exercise. Prior to the execution of the Exercise Agreements, the Series AAA Warrants were not exercisable until January 11, 2018. Pursuant to the Exercise Agreements, the Exercising Holders and the Company agreed that the Exercising Holders would exercise all of their Existing Warrants with respect to 4,665,000 shares of Common Stock underlying such Existing Warrants. The Series AAA Warrants and Series BBB Warrants were exercised at a price of $2.07 per share and $4.75 per share, respectively, which were their respective original exercise prices.

The Exercise Agreements also provide for the issuance of 1,166,250 Series DDD Warrants, each to purchase one share of Common Stock (the “Series DDD Warrants”). The Series DDD Warrants are initially exercisable no sooner than six months following issuance, and terminate six months following when the Series DDD Warrants are initially exercisable. The Series DDD Warrants have an exercise price no than less than $6.20 per share.

The Series DDD Warrants and the shares of Common Stock issuable upon the exercise of the Series DDD Warrants are not being registered under the Securities Act of 1933,outstanding as amended, and are being offered pursuant to the exemption provided in Section 4(a)(2) under the Securities Act or Rule 506(b) promulgated thereunder. Pursuant to the Exercise Agreements, the Series DDD Warrants shall be substantially in the form of the Existing Warrants and the Company will be required to register for resale the shares of Common Stock underlying the Series DDD Warrants.

In early October 2017, certain holders of the other 205,000 Series BBB Warrants and 108,455 Series AA Warrants from the February 14, 2017 Public Offering were exercised and, together with the exercise of the 4,665,000 Series AAA and Series BBB Warrants exercised by the Exercising Holders, the Company received aggregate gross proceeds of approximately $20.0 million in October 2017.

On October 27, 2017, the Company entered into an underwriting agreement (the “Underwriting Agreement”) with Oppenheimer & Co. Inc. (the “Underwriter”), relating to the issuance and sale (the “Offering”) of 2,640,000 shares (the “Shares”) of the Company’s common stock, $0.01 par value per share (the “Common Stock”), and warrants to purchase an aggregate of 1,320,000 shares of Common Stock. Each share of Common Stock is being sold together with 0.5 warrants (the “Investor Warrants”), each whole Investor Warrant being exercisable for one share of Common Stock, at an offering price of $2.50 per share and related Investor Warrants.

Pursuant to the terms of the Underwriting Agreement, the Underwriter has agreed to purchase the Shares and related Investor Warrants from the Company at a price of $2.325 per share and related Investor Warrants. Each Investor Warrant is exercisable six months from the date of issuance. The Investor Warrants have an exercise price of $3.00 per whole share, and expire five years from the date first exercisable.

The Company received $6.6 million of gross proceeds from the sale of the Shares and Investor Warrant. The Offering closed on October 31, 2017. This Offering was made pursuant to the Company’s effective shelf registration statement on Form S-3 (File No. 333-206789) filed with the Securities and Exchange Commission on September 4, 2015, and declared effective on September 25, 2015.

The Underwriting Agreement contains customary representations, warranties and agreements by the Company, customary conditions to closing, indemnification obligations of the Company and the Underwriters, including for liabilities under the Securities Act, other obligations of the parties, and termination provisions. The Company also agreed to issue to the Underwriter warrants to purchase up to 66,000 shares of the Company’s common stock, such issuance being exempt from registration pursuant to Section 4(a)(2) of the Securities Act.

Corporate Information

We were founded in 1982 and are a Delaware corporation. Our shares of common stock trade on The NASDAQ Capital Market under the symbol “CLSN.” Our principal executive offices are located at 997 Lenox Drive, Suite 100, Lawrenceville, New Jersey 08648. Our telephone number is (609) 896-9100 and our website is www.celsion.com. The information available on or through our website is not part of, nor incorporated by reference into, this prospectus, and should not be relied upon.

Description of the Private Placement

As previously reported, on July 6, 2017, the Company entered into a securities purchase agreement (the “Purchase Agreement”) with certain investors pursuant to which the Company agreed, among other things, to issue 2,435,000 Series AAA Warrants (the “Series AAA Warrants”) and 2,435,000 Series BBB Warrants (the “Series BBB Warrants” and together with the Series AAA Warrants, the “Existing Warrants”), each to purchase one share of common stock of the Company, par value $0.01 (“Common Stock”), to such investors in a private placement.

On October 4, 2017, the Company entered into letter agreements (the “Exercise Agreements”) with the holders of certain of the Existing Warrants (the “Exercising Holders”). The Exercise Agreements amend the Series AAA Warrants to permit their immediate exercise. Prior to the execution of the Exercise Agreements, the Series AAA Warrants were not exercisable until January 11, 2018. Pursuant to the Exercise Agreements, the Exercising Holders and the Company agreed that the Exercising Holders would exercise all of their Existing Warrants with respect to 4,665,000 shares of Common Stock underlying such Existing Warrants. The Series AAA Warrants and Series BBB Warrants will be exercised at a price of $2.07 per share and $4.75 per share, respectively, which were their respective original exercise prices.

The Exercise Agreements also provide for the issuance of 1,166,250 Series DDD Warrants in a concurrent private placement, each to purchase one share of Common Stock (the “Series DDD Warrants”). The Series DDD Warrants are initially exercisable twelve (12) months following issuance, and terminate six months following when the Series DDD Warrants are initially exercisable. The Series DDD Warrants have an exercise price $6.20 per share. Subject to limited exceptions, a holder of a Series DDD Warrant will not have the right to exercise any portion of its warrants if the holder, together with its affiliates, would beneficially own in excess of 4.99% of the number of shares of Common Stock outstanding immediately after giving effect to such exercise (the “Beneficial Ownership Limitation”); provided, however, that upon 61 days’ prior notice to the Company, the holder may increase or decrease the Beneficial Ownership Limitation, provided that in no event shall the Beneficial Ownership Limitation exceed 9.99%.

We filed the registration statement on Form S-1, of which this prospectus is a part, to fulfill our contractual obligations under the Exercise Agreement to provide for the resale by these investors of up to 1,166,250 shares of common stock issuable upon exercise of the warrants. We agree to use commercially reasonable efforts to cause such registration to become effective 60 days following the date of issuance of the warrants and to keep such registration statement effective at all times until (a) the warrant shares are sold under such registration statement or pursuant to Rule 144 under the Securities Act, (b) the warrant shares may be sold without volume or manner-of-sale restrictions pursuant to Rule 144 under the Securities Act, and (c) the one and one-half year anniversary of the date of the issuance of the warrants, whichever is the earliest to occur.

On October 31, 2017, the Company issued warrants to purchase up to 66,000 shares of Common Stock in a private placement. The exercise price of the warrants was equal to $2.87 per share of Common Stock. The representative’s warrants have been deemed underwriting compensation by FINRA and are therefore subject to a 180-day lock-up pursuant to Rule 5110(g)(1) of FINRA’s Rules.

We issued 82,193 shares of Common Stock in a private placement to satisfy obligations from the July 6, 2017 Common Stock Offering.

The Offering

hereof. The number of shares of our common stock shown aboveultimately offered for sale by Aspire Capital is dependent upon the number of shares purchased by Aspire Capital under the Purchase Agreement.

Pursuant to be outstanding immediately beforethe Purchase Agreement and the Registration Rights Agreement, we are registering 4,500,000 shares of our common stock under the Securities Act, which includes the Commitment Shares that have already been issued to Aspire Capital and 4,400,000 shares of common stock which we may issue to Aspire Capital after this offeringregistration statement is baseddeclared effective under the Securities Act. All 4,500,000 shares of common stock are being offered pursuant to this prospectus. Under the Purchase Agreement, we have the right but not the obligation to issue more than the 4,400,000 shares of common stock included in this prospectus to Aspire Capital. As of the date hereof, we do not have any plans or intent to issue to Aspire Capital any shares of common stock in addition to the 4,500,000 shares of common stock offered hereby.

After the Securities and Exchange Commission has declared effective the registration statement of which this prospectus is a part, on 8,354,679 any trading day on which the closing sale price of our common stock is not less than $0.25 per share, we have the right, in our sole discretion, to present Aspire Capital with a Purchase Notice, directing Aspire Capital (as principal) to purchase up to 100,000 shares outstandingof our common stock per business day, up to $10.0 million of our common stock in the aggregate over the term of the Purchase Agreement, at a Purchase Price calculated by reference to the prevailing market price of our common stock over the preceding 10-business day period (as more specifically described below); however, no sale pursuant to a Purchase Notice may exceed $500,000 per trading day.

In addition, on any date on which we submit a Purchase Notice to Aspire Capital for 100,000 Purchase Shares, we also have the right, in our sole discretion, to present Aspire Capital with a VWAP Purchase Notice directing Aspire Capital to purchase an amount of stock equal to up to 30% of the aggregate shares of the Company’s common stock traded on the Nasdaq Capital Market on the next trading day, subject to the VWAP Purchase Share Volume Maximum and the VWAP Minimum Price Threshold. The VWAP Purchase Price is calculated by reference to the prevailing market price of our common stock (as more specifically described below).

The Purchase Agreement provides that the Company and Aspire Capital shall not effect any sales under the Purchase Agreement on any purchase date where the closing sale price of our common stock is less than the Floor Price. There are no trading volume requirements or restrictions under the Purchase Agreement, and we will control the timing and amount of any sales of our common stock to Aspire Capital. Aspire Capital has no right to require any sales by us, but is obligated to make purchases from us as we direct in accordance with the Purchase Agreement. There are no limitations on use of September 30, 2017, and excludes, asproceeds, financial or business covenants, restrictions on future financings, rights of first refusal, participation rights, penalties or liquidated damages in the Purchase Agreement. Aspire Capital may not assign its rights or obligations under the Purchase Agreement. The Purchase Agreement may be terminated by us at any time, at our discretion, without any penalty or cost to us.

Purchase Of Shares Under The Common Stock Purchase Agreement

Under the common stock Purchase Agreement, on any trading day selected by us on which the closing sale price of our common stock exceeds $0.25 per share, we may direct Aspire Capital to purchase up to 100,000 shares of our common stock per trading day. The Purchase Price of such date:shares is equal to the lesser of:

In addition, on any date on which we submit a Purchase Notice to Aspire Capital for purchase of 100,000 shares, we also have the right to direct Aspire Capital to purchase an amount of stock equal to up to 30% of the aggregate shares of our common stock traded on the Nasdaq Capital Market on the next trading day, subject to the VWAP Purchase Share Volume Maximum and the VWAP Minimum Price Threshold, which is equal to the greater of (a) 80% of the closing price of the Company’s common stock on the business day immediately preceding the VWAP Purchase Date or (b) such higher price as set forth by the Company in the VWAP Purchase Notice. The VWAP Purchase Price of such shares is the lower of:

The Purchase Price will be adjusted for any reorganization, recapitalization, non-cash dividend, stock split, or other similar transaction occurring during the trading day(s) used to compute the Purchase Price. We may deliver multiple Purchase Notices and VWAP Purchase Notices to Aspire Capital from time to time during the term of the Purchase Agreement, so long as the most recent purchase has been completed.

Minimum Share Price

Under the Purchase Agreement, we and Aspire Capital may not effect any sales of shares of our common stock under the Purchase Agreement on any trading day that the closing sale price of our common stock is less than $0.25 per share.

Events of Default

No sales are permitted to be made under the Purchase Agreement upon the occurrence of any of the following, among other, events of default:

SubsequentThe Purchase Agreement will be automatically terminated in the event of any participation in insolvency or bankruptcy proceedings by or against us.

Our Termination Rights

The Purchase Agreement may be terminated by us at any time, at our discretion, without any penalty or cost to September 30, 2017,us.

No Short-Selling or Hedging by Aspire Capital

Aspire Capital has agreed that neither it nor any of its agents, representatives and affiliates shall engage in any direct or indirect short-selling or hedging of our common stock during any time prior to the Company issued 4,978,445termination of the Purchase Agreement.

Effect of Performance of the Purchase Agreement on Our Stockholders

The Purchase Agreement does not limit the ability of Aspire Capital to sell any or all of the 4,500,000 shares registered in this offering. It is anticipated that shares registered in this offering will be sold over a period of up to approximately thirty months from the date of this prospectus. The sale by Aspire Capital of a significant amount of shares registered in this offering at any given time could cause the market price of our common stock to decline and/or to be highly volatile. Aspire Capital may ultimately purchase all, some or none of the 4,400,000 shares of common stock uponnot yet issued but registered in this offering. After it has acquired such shares, it may sell all, some or none of such shares. Therefore, sales to Aspire Capital by us pursuant to the exercisePurchase Agreement also may result in substantial dilution to the interests of outstanding warrants, 2,640,000other holders of our common stock. However, we have the right to control the timing and amount of any sales of our shares issued from an underwritten equity offering completed on October 31, 2017to Aspire Capital and 89,217the Purchase Agreement may be terminated by us at any time at our discretion without any penalty or cost to us.

Percentage of Outstanding Shares After Giving Effect to the Purchased Shares Issued to Aspire Capital

In connection with entering into the Purchase Agreement, we authorized the sale to Aspire Capital of up to $10.0 million of our shares of common stock. However, we estimate that we will sell no more than 4,500,000 shares from other transactions. Including such issuances, asto Aspire Capital under the Purchase Agreement (exclusive of November 21, 2017, the Company had 16,062,341 shares of common stock outstanding.

RISK FACTORS

Investing in our securities involves a high degree of risk. You should carefully consider and evaluateCommitment Shares), all of which are included in this offering. Subject to any required approval by our board of directors, we have the information containedright but not the obligation to issue more than the 4,500,000 shares included in this prospectus to Aspire Capital under the Purchase Agreement. In the event we elect to issue more than 4,500,000 shares under the Purchase Agreement, we will be required to file a new registration statement and inhave it declared effective by the documents incorporatedSEC. The number of shares ultimately offered for sale by referenceAspire Capital in this prospectus before you decide to purchase our securities. In particular, you should carefully consider and evaluateoffering is dependent upon the risks and uncertainties described in “Part I — Item 1A. Risk Factors”number of our most recent Annual Report on Form 10-K, as updatedshares purchased by the additional risks and uncertainties set forth in our most recent Quarterly Reports on Form 10-Q and in other filings we make with the SEC, as well as the risks and uncertainties describedAspire Capital under the heading “Risk Factors” contained in the applicable prospectus or in any other document incorporated by reference into this prospectus. Any of the risks and uncertainties set forth therein could materially and adversely affect our business, results of operations and financial condition, which in turn could materially and adversely affect the trading price or value of our securities. As a result, you could lose all or part of your investment.

USE OF PROCEEDS

All shares of our common stock offered by this prospectus are being registered for the account of the selling stockholders. We will not receive any of the proceeds from the sale of these shares. We will receive proceeds from the cash exercise of the warrants which, if exercised in cash with respect to all of the 1,232,250 shares of common stock, would result in gross proceeds of $7,420,170 to us. We will use any proceeds received by us from the cash exercise of the warrants for general corporate purposes, including research and development activities, capital expenditures and working capital. We may also use all or a portion of such proceeds to fund possible investments in, or acquisitions of, complementary businesses, technologies or products, but we currently have no agreements or commitments with respect to any investment or acquisition. We cannot predict when or if the warrants will be exercised, and it is possible that the warrants may expire and never be exercised.

MARKET INFORMATION FOR OUR COMMON STOCK

Purchase Agreement. The following table sets forth the highnumber and low reported closingpercentage of outstanding shares to be held by Aspire Capital after giving effect to the sale prices on NASDAQ for the periods indicated:of shares of common stock issued to Aspire Capital at varying purchase prices: