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As filed with the Securities and Exchange Commission March 16, 2018on April 17, 2023
Registration Statement No. 333-​

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549
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FORM S-3
REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933
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CARISMA THERAPEUTICS INC.
Eleven Biotherapeutics, Inc.
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(Exact name of registrant as specified in its charter)
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Delaware
26-2025616
(State or other jurisdiction of
incorporation or organization)​
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26-2025616
(I.R.S. Employer
Identification No.)Number)
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245 First3675 Market Street, Suite 1800
Cambridge, MA
(617) 444-8550200
Philadelphia, PA 19104
(267) 491-6422
(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)
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Stephen A. Hurly
Steven Kelly
President and Chief Executive Officer
Eleven Biotherapeutics,
Carisma Therapeutics Inc.
245 First
3675 Market Street, Suite 1800
Cambridge, MA 02142
(617) 444-8550200
Philadelphia, PA 19104
(267) 491-6422
(Name, address, including zip code, and telephone number, including area code, of agent for service)
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Copy to:
Copies to:Brian A. Johnson
Wilmer Cutler Pickering Hale and Dorr LLP
7 World Trade Center
250 Greenwich Street
New York, New York 10007
Telephone: (212) 230-8800
Fax: (212) 230-8888

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 Steven J. Abrams
Hogan Lovells US LLP
1735 Market Street, 23rd Floor
Philadelphia, Pennsylvania 19103
(267) 675-4600
Approximate date of commencement of proposed sale to the public:public: From time to time on or after the effective date of this Registration Statement.registration statement becomes effective.
If the only securities being registered on this Form are being offered pursuant to dividend or interest reinvestment plans, please check the following box.  ¨box: ☐


If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, other than securities offered only in connection with dividend or interest reinvestment plans, check the following box.  xbox: ☒
If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ¨☐                  
If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ¨☐
If this Form is a registration statement pursuant to General Instruction I.D. or a post-effective amendment thereto that shall become effective upon filing with the Commission pursuant to Rule 462(e) under the Securities Act, check the following box. ¨☐
If this Form is a post-effective amendment to a registration statement filed pursuant to General Instruction I.D. filed to register additional securities or additional classes of securities pursuant to Rule 413(b) under the Securities Act, check the following box. ¨☐
Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company”company,” and "emerging“emerging growth company"company” in Rule 12b-2 of the Exchange Act:Act.
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Large accelerated filer
☐
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Accelerated filer
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Non-accelerated filer​
¨Non-accelerated filer  (Do not check if a smaller reporting company)
☒
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Smaller reporting company
☒
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x​
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Emerging Growthgrowth company
☐
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x​

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act. x
The registrant is an emerging growth company, as defined in Section 2(a) of the Securities Act. This Registration Statement complies with the requirements that apply to an issuer that is an emerging growth company.


CALCULATION OF REGISTRATION FEE

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Title of Securities to be
Registered
 
Amount to be
Registered
(1)(2)
 
  Proposed Maximum  
Offering Price Per Share
(3)
 
  Proposed Maximum  
Aggregate Offering Price
(3)
 
Amount of
Registration Fee
(4)
Debt Securities —
 —
 —
  —
Common Stock, par value $0.001 per share —
 —
 —
  —
Preferred Stock —
 —
 —
  —
Depositary Shares(5) —
 —
 —
  —
Purchase Contracts —
 —
 —
  —
Purchase Units —
 —
 —
  —
Warrants —
 —
 —
  —
Total —
 —
 $150,000,000(3) $18,675.00
          
(1)Not specified as to each class of security to be registered pursuant to General Instruction II.D. of Form S-3 under the Securities Act of 1933, as amended, or Securities Act.
(2)There are being registered hereunder an indeterminate number of securities of each identified class as may be issued from time to time at indeterminate prices, as well as an indeterminate number of shares of common stock and preferred stock as may be issued upon conversion, exercise or exchange of any of the securities issued directly under this registration statement. No separate consideration is payable for any shares of common stock and preferred stock so issued upon conversion, exercise or exchange. Securities registered hereby may be sold separately, together or in units with other securities registered hereby.


(3)
The proposed maximum offering price per security and the proposed maximum aggregate offering price per class of security will be determined from time to time by the Registrant in connection with the issuance by the Registrant of the securities registered hereunder and is not specified as to each class of security pursuant to General Instruction II.D. of Form S-3 under the Securities Act. The proposed maximum aggregate offering price has been estimated solely for the purpose of calculating the registration fee in accordance with Rule 457(o) under the Securities Act. The aggregate maximum offering price of all securities issued pursuant to this registration statement will not exceed $150,000,000.
(4)
Pursuant to Rule 415(a)(6) under the Securities Act, the securities registered pursuant to this registration statement include unsold securities previously registered by the registrant on the registrant's registration statement (File No. 333-202676) filed on March 12, 2015 and declared effective on March 20, 2015 (the “2015 Registration Statement”). The 2015 Registration Statement registered the offer and sale of an indeterminate number or amount of debt securities, common stock, preferred stock, depositary shares, purchase contracts, purchase units and warrants, having an aggregate initial offering price of $200,000,000, a portion of which remains unsold as of the date of filing this registration statement. The Registrant has determined to include in this registration statement certain unsold securities under the 2015 Registration Statement with an aggregate offering price of $150,000,000 (the “Unsold Securities”). Pursuant to Rule 415(a)(6) under the Securities Act, the filing fee of $18,675.00 relating to the Unsold Securities will continue to be applied to the Unsold Securities registered pursuant to this registration statement and is offset against the total registration fees due hereunder. Accordingly, no additional filing fee is being paid herewith. Pursuant to Rule 415(a)(6) under the Securities Act, the offering of the Unsold Securities under the 2015 Registration Statement will be deemed terminated as of the date of effectiveness of this registration statement.
(5)Each depositary share will be issued under a deposit agreement, will represent an interest in a fractional share or multiple shares of preferred stock and will be evidenced by a depositary receipt.

The Registrantregistrant hereby amends this registration statement on such date or dates as may be necessary to delay its effective date until the Registrantregistrant shall file a further amendment thatwhich specifically states that this registration statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933 or until this 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 Registrant has an existing “shelf” registration statement, File No. 333-202676, that was declared effective on March 20, 2015 and which expires on March 20, 2018 pursuant to Rule 415(a)(5) under the Securities Act. Pursuant to Rule 415(a)(6) promulgated under the Securities Act, the filing fees previously paid in connection with the securities being registered hereunder will continue to be applied to such securities. In accordance with Rule 415(a)(5) and Rule 415(a)(6), the Registrant may continue to offer and sell the securities covered by the existing shelf registration statement during the grace period afforded by Rule 415(a)(5). If the Registrant sells any securities being registered hereunder during the grace period, the Registrant will identify in a pre-effective amendment to this registration statement the new amount of securities to be carried forward to this registration statement in reliance upon Rule 415(a)(6).
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TABLE OF CONTENTS

The information in this prospectus is not complete and may be changed. WeThe selling stockholders named in this prospectus may not sell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This prospectus is not an offer to sell these securities and it isthe selling stockholders named in this prospectus are not soliciting an offeroffers to buy these securities in any statejurisdiction where the offer or sale is not permitted.
Subject To Completion, Dated March 16, 2018to completion, dated April 17, 2023
PROSPECTUS
$150,000,000[MISSING IMAGE: lg_carismatherapeutics-4c.jpg]

3,730,608 SHARES
ebioforms3universalsh_image1.jpgCOMMON STOCK

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Debt Securities
Common Stock
Preferred Stock
Depository Shares
Purchase Contracts
Purchase Units
Warrants


This prospectus relates to the resale of up to 3,730,608 shares of common stock of Carisma Therapeutics Inc. by the selling stockholders identified in this prospectus. We are registering these shares on behalf of the selling stockholders, to be offered and sold by them from time to time. We will not receive any proceeds from the sale of the shares offered by this prospectus.
We have agreed, pursuant to a Registration Rights Agreement that we entered into with the selling stockholders, to bear all of the expenses incurred in connection with the registration of these shares. The selling stockholders will pay or assume underwriting discounts, commissions, fees of underwriters, selling brokers or dealer managers and similar expenses, if any, incurred for the sale of shares of our common stock.
The selling stockholders identified in this prospectus, or their transferees, pledgees, donees or other successors-in-interest, may offer and sell up to $150,000,000 in the aggregate of the securities identified aboveshares from time to time in onethrough public or more offerings. This prospectus provides a general description of the securities that we may offer. Each time that we offer securities under this prospectus, we will provide the specific terms of the securities offered, including the public offering price, in a supplementprivate transactions at prevailing market prices, at prices related to this prospectus. Any prospectus supplement may add to, updateprevailing market prices or change information contained in this prospectus. You should read this prospectus and any applicable prospectus supplement together with additional information described under the heading “Where You Can Find More Information” before you make your investment decision.
The securities may be sold by us to or through underwriters or dealers, directly to purchasers or through agents designated from time to time.at privately negotiated prices. For additional information on the methods of sale you should refer tothat may be used by the selling stockholders, see the section entitled “Plan of Distribution” in this prospectus and the comparable section of any applicable prospectus supplement. If any underwriters are involved in the sale of the securities with respect to whichprospectus.
We may amend or supplement this prospectus is being delivered,from time to time by filing amendments or supplements as required. You should read the names of such underwriters and any applicable discounts or commissions and over-allotment options will be set forthentire prospectus, including the documents incorporated by reference in the applicable prospectus supplement. No securities may be sold without delivery of this prospectus, and the applicable prospectus supplement.any amendments or supplements carefully before you make an investment decision.
Our common stock tradesis traded on the Nasdaq Global Market or Nasdaq, under the ticker symbol “EBIO.“CARM.” On March 16, 2018,April 14, 2023, the last reportedclosing sale price per share of our common stock on the Nasdaq Global Market was $1.07$3.56 per share. You are urged to obtain current market quotations for our common stock.
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Investing in our common stock involves significant risks. See the information included under “Risk Factors” on page 4 of this prospectus and under similar headings in the documents incorporated by reference in this prospectus for a discussion of the factors you should carefully consider before deciding to purchase shares of our common stock.
INVESTING IN OUR SECURITIES INVOLVES A HIGH DEGREE OF RISK. RISKS ASSOCIATED WITH AN INVESTMENT IN OUR SECURITIES WILL BE DESCRIBED IN THE APPLICABLE PROSPECTUS SUPPLEMENT AND CERTAIN OF OUR FILINGS WITH THE SECURITIES AND EXCHANGE COMMISSION INCORPORATED BY REFERENCE INTO THIS PROSPECTUS, AS DESCRIBED UNDER “RISK FACTORS” ON PAGE 5.
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Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus. Any representation to the contrary is a criminal offense.

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The date of this prospectus is                 , 2018.2023


TABLE OF CONTENTS

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TABLE OF CONTENTS
​​​Page​
PROSPECTUS SUMMARY
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THE OFFERING
Page​​​​3​​
RISK FACTORS
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ABOUT THIS PROSPECTUS
FORWARD-LOOKING STATEMENTS
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FORWARD-LOOKING STATEMENTS
1
THE COMPANY
3
RISK FACTORS
5
USE OF PROCEEDS
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RATIO OF EARNINGS TO FIXED CHARGES
SELLING STOCKHOLDERS
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DESCRIPTION OF OUR DEBT SECURITIESCAPITAL STOCK
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DESCRIPTION OF OUR CAPITAL STOCK
14
DESCRIPTION OF OUR DEPOSITARY SHARES
21
DESCRIPTION OF PURCHASE CONTRACTS AND PURCHASE UNITS
23
DESCRIPTION OF OUR WARRANTS
24
FORMS OF SECURITIES
25
PLAN OF DISTRIBUTION
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​​​2617​​
LEGAL MATTERS
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​​​2919​​
EXPERTS
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INCORPORATION BY REFERENCE
30
WHERE YOU CAN FIND MORE INFORMATION​​​​20​​
31INCORPORATION BY REFERENCE
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ABOUT THIS PROSPECTUS
This prospectus is a part of a registration statement that we filed with the Securities and Exchange Commission, or the SEC, using a “shelf” registration process. Under this shelf registration process, we may offer to sell any of the securities, or any combination of the securities, described in this prospectus, in each case in one or more offerings, up to a total dollar amount of $150,000,000.
This prospectus provides youYou should rely only with a general description ofon the securities that we may offer. Each time securities are sold under the shelf registration statement, we will provide a prospectus supplement or free writing prospectus that will contain specific information about the terms of those securities and the terms of that offering. The prospectus supplement or free writing prospectus may also add, update or change information contained in this prospectus. You should read both this prospectus and any prospectus supplement or free writing prospectus, including all documents incorporated by reference herein and therein, together with the additional information described under “Where You Can Find More Information” below.
The registration statement that contains this prospectus, including the exhibits to the registration statement and the information incorporated by reference, contains additional information about the securities offered under this prospectus. That registration statement can be read at the SEC website or at the SEC offices mentioned below under the heading “Where You Can Find More Information.” You should read the exhibits carefully for provisions that may be important to you.
We have not authorized any dealer, agent or other person to give any information or to make any representation other than those contained or incorporated by reference in this prospectus and any accompanying prospectus supplementprospectus. We have not authorized anyone to provide you with different or free writing prospectus. You must not rely upon any information or representation not contained or incorporated by reference in this prospectus or an accompanying prospectus supplement or free writing prospectus.additional information. This prospectus and the accompanying prospectus supplement or free writing prospectus, if any, dodoes not constitute an offer to sell or the solicitation of an offer to buy any securities other than the registered securities to which they relate, nor dodescribed in this prospectus and the accompanying prospectus supplement or free writing prospectus, if any, constitute an offer to sell or the solicitation of an offer to buy such securities in any jurisdiction to any person to whom it is unlawful to makecircumstances in which such offer or solicitation in such jurisdiction.is unlawful. You should not assume that the information containedappearing in this prospectus and the accompanying prospectus supplement or free writing prospectus, if any, is accurate on any date subsequent to the date set forth on the frontonly as of such document or that any information we have incorporated by reference is correct on any date subsequent to the date of the document incorporated by reference, even though this prospectus, regardless of the time of delivery of this prospectus or of any sale of common stock. Our business, financial condition, results of operations and any accompanying prospectus supplement or free writing prospectus is delivered or securities are sold on a later date.prospects may have changed materially since such date.
ReferencesUnless the context otherwise indicates, references in this prospectus to the terms “the Company,“Company,” “Eleven,“Carisma,” “we,” “our” and “us” refer, collectively, to Carisma Therapeutics Inc., a Delaware corporation, and its consolidated subsidiaries.

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PROSPECTUS SUMMARY
This summary highlights, and is qualified in its entirety by, the more detailed information included elsewhere in this prospectus or incorporated by reference in this prospectus. This summary does not contain all of the information that you should consider before investing in our common stock. You should read and carefully consider the entire prospectus, including the information incorporated by reference in the prospectus, especially the risks of investing in our common stock discussed in the “Risk Factors” section.
Carisma Therapeutics Inc.
Carisma is a clinical stage cell therapy company focused on utilizing its proprietary macrophage and monocyte cell engineering platform to develop transformative immunotherapies to treat cancer and other similar terms meanserious diseases. We have created a comprehensive cell therapy platform to enable the therapeutic use of engineered macrophages and monocytes, which belong to a subgroup of white blood cells called myeloid cells. Macrophages and monocytes are part of the innate immune system and can detect and degrade harmful substances through a process referred to as phagocytosis, in which the harmful substance is engulfed and destroyed and in turn leads to the activation of a broad immune response.
To harness the powerful immunologic functions of macrophages against cancer, we have developed a proprietary Chimeric Antigen Receptor Macrophage, or CAR-M, platform technology. Chimeric antigen receptors, or CARs, are synthetically engineered receptors that are designed to bestow immune cells with the ability to target specific antigens on the surface of cancer cells. By introducing CARs into macrophage and monocyte cells, we aim to redirect their potent innate immune functions against cancer. Our CAR-M platform technology incorporates proprietary tumor targeting constructs vectors to deliver CARs to macrophages and monocytes and novel manufacturing processes. Our CAR-M therapeutics are designed to infiltrate the solid tumor microenvironment, kill cancer cells via targeted phagocytosis, and activate other immune cells, such as T-cells, to initiate a robust anti-tumor immune response.
Our lead product candidate CT-0508, the first CAR-M to be evaluated in a human clinical trial, is an ex vivo autologous cell therapy product candidate, wherein immune cells from blood drawn from a patient are engineered outside of the body and reinfused into the same patient. CT-0508 is intended to treat solid tumors that overexpress HER2, a protein that is overexpressed on the surface of a variety of solid tumors, including breast cancer, gastric cancer, esophageal cancer, salivary gland cancer, and numerous others. Beyond CT-0508, we have a broad pipeline of cell therapy assets in various stages of pre-clinical development. In addition to the development of ex vivo CAR-M cell therapies, we are also developing in vivo CAR-M gene therapies, wherein immune cells are directly engineered within the patient’s body.
Corporate Information
We were incorporated under the laws of the state of Delaware on February 25, 2008 under the name NewCo LS14, Inc. We subsequently changed our name to DeNovo Therapeutics, Inc. in September 2008, to Eleven Biotherapeutics, Inc. in February 2010, to Sesen Bio, Inc. in May 2018 and to Carisma Therapeutics Inc. in March 2023, in connection with the completion of the Merger (as defined below).
Our principal executive offices are located at 3675 Market Street, Suite 200, Philadelphia, Pennsylvania 19104, and our telephone number is (267) 491-6422. Our website address is www.carismatx.com. The information contained on, or that can be accessed through, our website is not a part of this prospectus. We have included our website address in this prospectus solely as an inactive textual reference.
Private Placement
On March 7, 2023, we completed a business combination in accordance with the terms of the Agreement and Plan of Merger and Reorganization, dated as of September 20, 2022, as subsequently amended, by and among the Company, CTx Operations, Inc. (formerly CARISMA Therapeutics Inc.), or Legacy Carisma, and Seahawk Merger Sub, Inc., a Delaware corporation and a wholly owned subsidiaries, unless we state otherwisesubsidiary of the Company, or Merger Sub, pursuant to which, among other matters, Merger Sub merged with and into Legacy Carisma, with Legacy Carisma continuing as a wholly owned subsidiary of the Company and the surviving corporation of the merger, or the context indicates otherwise.Merger. As of the effective time of the Merger, we changed our name from “Sesen


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Bio, Inc.” to “Carisma Therapeutics Inc.” and the business conducted by the Company became primarily the business conducted by Legacy Carisma, as described above.
Immediately prior to the effective time of the Merger, Legacy Carisma issued an aggregate of 1,964,101 shares of Legacy Carisma common stock for an aggregate purchase price of approximately $30.6 million, or the Private Placement, pursuant to an Amended and Restated Subscription Agreement, dated as of December 29, 2022, or the Subscription Agreement, between Legacy Carisma and the selling stockholders. All of the shares of Legacy Carisma common stock held by the selling stockholders immediately prior to the effective time of the Merger, including shares of Legacy Carisma common stock issued in connection with the Private Placement, were exchanged into an aggregate of 3,730,608 shares of the Company’s common stock at the effective time of the Merger.
For a detailed description of the transactions contemplated by the Subscription Agreement with the selling stockholders, see the section entitled “Selling Stockholders” in this prospectus. We filed the registration statement on Form S-3, of which this prospectus forms a part, to fulfill our contractual obligations under the Registration Rights Agreement with the selling stockholders, dated as of March 7, 2023, or the Registration Rights Agreement, entered into concurrently with the consummation of the Private Placement to provide for the resale by the selling stockholders of the shares of common stock acquired pursuant to the Subscription Agreement.

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THE OFFERING
Common stock offered by selling stockholders
3,730,608 shares.
Use of proceeds
We will not receive any proceeds from the sale of shares in this offering.
Risk Factors
You should read the “Risk Factors” section of this prospectus for a discussion of factors to consider carefully before deciding to invest in shares of our common stock.
Nasdaq Global Market symbol
“CARM”

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RISK FACTORS
Investing in our securities involves significant risks. You should carefully consider the risks and uncertainties described in Exhibit 99.3 to our Current Report on Form 8-K filed with the SEC on March 8, 2023, as updated by our subsequent filings, which are incorporated by reference into this prospectus, before deciding whether to purchase shares of our common stock. Each of the risk factors could adversely affect our business, financial condition, results of operations, or prospects, as well as adversely affect the value of an investment in our common stock, and the occurrence of any of these risks might cause you to lose all or part of your investment. Additional risks not presently known to us or that we currently believe are immaterial may also significantly impair our business operations.

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FORWARD-LOOKING STATEMENTS
This prospectus includingand the documents that we incorporateinformation incorporated by reference herein, includesin this prospectus contain certain forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, or the Securities Act, and Section 21E of the Securities Exchange Act of 1934, as amended, or the Exchange Act. For this purpose, anyAll statements, contained herein, other than statements of historical fact,facts, contained in this prospectus and the information incorporated by reference herein, including statements regarding our strategy, future operations, future product research or development, future financial position, future revenues, projected costs, prospects, plans and objectives of management, are forward-looking statements. The words “anticipate,” “believe,” “goals,” “estimate,” “expect,” “intend,” “may,” “might,” “plan,” “predict,” “project,” “target,” “potential,” “will,” “would,” “could,” “should,” “continue”“anticipates”, “believes”, “could”, “estimates”, “expects”, “intends”, “may”, “plans”, “potential”, “predicts”, “projects”, “should”, “will”, “would” and the negative version of these words and other similar expressions are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words. Such forward-looking statements are subject to various risks and uncertainties. Accordingly, there are or will be important factors that could cause actual outcomes or results to differ materially from those indicated in these statements.
The forward-looking statements in this prospectus and the documents incorporated by reference in the prospectus include, among other things, the statements about:
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the timing and conduct of our expected future lossongoing Phase 1 clinical trial of CT-0508 and accumulated deficit levels;our planned clinical trial utilizing CT-0508 in combination with pembrolizumab;
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•
the timing and conduct of our planned clinical trial of CT-0525 for solid tumors that overexpress HER2;
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the timing and conduct of our planned clinical trial of CT-1119 for advanced mesothelin-positive solid tumors;
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the timing and conduct of our planned clinical trial of CT-0729 for prostate-specific membrane antigen positive castrate resistant prostate cancer;
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our projected financial positionability to replicate in later clinical trials positive results found in preclinical studies and estimatedearly-stage clinical trials of our product candidates;
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our plans to conduct discovery and pre-clinical testing of the development of in vivo CAR-M therapeutics for up to twelve oncology targets, as well as multiple other targets and indications;
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our ability to successfully enroll patients in and complete clinical trials;
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our plans to conduct discovery and pre-clinical testing of other product candidates;
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our ability to realize the anticipated benefits of our research and development programs, strategic partnerships, research and licensing programs and academic and other collaborations;
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the timing of applying for and receiving, and our ability to maintain, marketing approvals from applicable regulatory authorities for our product candidates;
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our ability to obtain and maintain intellectual property protection and regulatory exclusivity for CT-0508 and any other product candidates we are developing or may develop in the future;
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acceptance of CT-0508 and any other product candidates, if and when approved, by patients, the medical community and third-party payors;
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our expectations regarding our ability to fund our operating expenses and capital expenditure requirements with our cash, burn rate;cash equivalents and short-term investments;
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the potential advantages of our product candidates;
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our estimates regarding the potential market opportunity for our product candidates;
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our commercialization and manufacturing capabilities and strategy;
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the impact of COVID-19 on our business and operations;
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our estimates regarding expenses, future revenues,revenue, capital requirements and needs for and ability to obtain, additional financing;
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our competitive position;
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•
the impact of government laws and regulations;
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•
our ability to continue as a going concern;recognize the benefits of the Merger and the effect the completion of the Merger will have on our business relationships, operating results and business generally;
our need to raise substantial additional capital to fund our operations;​
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the potential impairmentreceipt of any payments under the contingent value rights issued to our goodwillstockholders in connection with the closing of the Merger, the realization of value for Sesen Bio, Inc. legacy assets and indefinite lived intangible assets;
the effect of recent changes in our senior management team on our business;
the success, costamount and timing of distributions to be made to our pre-clinical studiesstockholders, if any; and clinical trials
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•
political and economic developments.
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Forward-looking statements inherently involve known and unknown risks, uncertainties, and other factors, which may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements. You are cautioned that these forward-looking statements are only predictions and are subject to risks, uncertainties and assumptions. You should carefully review the risk factors and cautionary statements described in the United States, Canada and in other foreign jurisdictions;
documents we file from time to time with the potential that results of pre-clinical studies and clinical trials indicateSEC, specifically Exhibit 99.3 to our product candidates are unsafe or ineffective;
our dependenceCurrent Report on third parties, including contract research organizations, or CROs, inForm 8-K filed with the conduct ofSEC on March 8, 2023, as updated by our pre-clinical studies and clinical trials;
the difficulties and expenses associated with obtaining and maintaining regulatory approval of our product candidates and companion diagnostics, if any, in the United States, Canada and in other foreign jurisdictions, and the labeling under any approval we may obtain;
our plans and ability to develop and commercialize our product candidates;
our ability to achieve certain future regulatory, development and commercialization milestones under our license agreement, which we refer to as the License Agreement, with F. Hoffmann-La Roche Ltd and Hoffmann La-Roche Inc., or collectively, Roche;
market acceptance of our product candidates, the size and growth of the potential markets for our product candidates, and our ability to serve those markets;
obtaining and maintaining intellectual property protection for our product candidates and our proprietary technology;
the successful development of our commercialization capabilities, including sales and marketing capabilities; and
the success of competing therapies and products that are or become available.
Our product candidates are investigational biologics undergoing clinical development and have not been approved by the U.S. Food and Drug Administration, or FDA, Health Canada, or the European Commission. Our product candidates have not been, nor may they ever be, approved by any regulatory agency or competent authorities nor marketed anywhere in the world.
We may not actually achieve the plans, intentions or expectations disclosed in our forward-looking statements, and our stockholders should not place undue reliance on our forward-looking statements. Actual results or events could differ

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materially from the plans, intentions and expectations disclosed in the forward-looking statements we make. We have included important factors in the cautionary statements included in this prospectus, particularly in the “Risk Factors” section beginning on page 5 and those identified under the heading “Risk Factors” in our most recent Annual Report on Form 10-K, that could cause actual results or events to differ materially from the forward-looking statements that we make. Our forward-looking statements do not reflect the potential impact of any future acquisitions, mergers, dispositions, joint ventures or investments we may make.our Quarterly Reports on Form 10-Q and our other Current Reports on Form 8-K.
You should read this prospectus and the documents thatincorporated by reference in this prospectus and the documents we have filed as exhibits to the registration statement of which this prospectus formsis a part completely and with the understanding that our actual future results may be materially different from what we expect. The forward-looking statements contained in this prospectus are made as of the date of this prospectus, and we do not assume any obligation to update any forward-looking statements, whether as a result of new information, future events or otherwise, except as required by applicable law.


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THE COMPANY
OverviewUSE OF PROCEEDS
We are a biologics oncology company focused primarily on designing, engineeringnot selling any securities under this prospectus and developing targeted protein therapeutics. Our TPTs are single-protein therapeutics composedwe will not receive any proceeds from the sale of targeting moieties genetically fused via linker domains to cytotoxic protein payloads that are produced through our proprietary one-step manufacturing process. We target tumor cell surface antigens that allowshares by the selling stockholders.
The selling stockholders will pay any underwriting discounts, commissions, fees of underwriters, selling brokers or dealer managers and expenses incurred by the selling stockholders for rapid internalization intobrokerage, accounting, tax or legal services or any other expenses incurred by the targeted cancer cell and have limited expression on normal cells. We have designed our TPTs to overcome the fundamental efficacy and safety challenges inherentselling stockholders in existing antibody drug conjugates, or ADCs, where a payload is chemically attached to a targeting antibody.
Our most advanced product candidate is Vicinium, which is a locally-administered TPT. In a completed Phase 2 clinical trial,disposing of the 45 evaluable subjects treated with Vicinium, 40% achieved a complete response or no evidenceshares. We will bear all other costs, fees and expenses incurred in effecting the registration of disease at three months while 16% remained disease-free for at least 18 months. In the third quartershares covered by this prospectus, including, without limitation, all registration and filing fees, printing fees, Nasdaq listing fees and fees and expenses of 2015,our counsel and our accountants.

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SELLING STOCKHOLDERS
On March 7, 2023, we throughcompleted the Merger. As of the effective time of the Merger, we changed our subsidiary Viventianame from “Sesen Bio, Inc., or Viventia, commenced” to “Carisma Therapeutics Inc.” and the business conducted by the Company became primarily the business conducted by Legacy Carisma, as described above.
Immediately prior to the effective time of the Merger, Legacy Carisma issued an aggregate of 1,964,101 shares of Legacy Carisma common stock to the selling stockholders in the United States and CanadaPrivate Placement pursuant to the Subscription Agreement at a Phase 3 clinical trialpurchase price of Vicinium$15.60 per share of Legacy Carisma common stock, for an aggregate purchase price of approximately $30.6 million. The Private Placement was effected pursuant to an exemption from registration afforded by Section 4(a)(2) of the treatmentSecurities Act. At the effective time of subjects with high-grade non-muscle invasive bladder cancer, or NMIBC. We completed enrollment in this clinical trial in March 2018 and anticipate reporting topline three-month data in mid-2018 and topline twelve-month datathe Merger, the shares purchased by the selling stockholders in the second quarterPrivate Placement were exchanged for 3,730,608 shares of 2019. our common stock in the aggregate, based on the exchange ratio set forth in the Merger Agreement.
In June 2017,connection with the closing of the Private Placement, we entered into a Cooperative Research and Developmentthe Registration Rights Agreement, or CRADA, with the National Cancer Institute, or NCI, for the development of Vicinium in combination with AstraZeneca’s immune checkpoint inhibitor, durvalumab, for the treatment of NMIBC. Under the terms of the CRADA, the NCI will conduct a Phase 1 clinical trial in subjects with high-grade NMIBC to evaluate the safety, efficacy and biological correlates of Vicinium in combination with durvalumab.
Our second most advanced product candidate is Proxinium, a locally-administered TPT intended for the treatment of squamous cell carcinoma of the head and neck, or SCCHN. In our two Phase 1 clinical trials, 53% of evaluable subjects treated with Proxinium demonstrated antitumor activity with epithelial cell adhesion molecule, or EpCAM-expressing tumors as assessed by investigator’s clinical measurements, the investigator’s overall assessment including qualitative changes, and assessment of available radiologic data. In addition, three out of the four subjects with complete responses of injected tumors had regression or complete resolution of adjacent non-injected lesions. In a Phase 2 clinical trial, we observed tumor shrinkage in 10 of the 14 evaluable subjects (71.4%). We intend to initiate a Phase 1/2a clinical trial that will explore the potential of Proxinium in combination with a checkpoint inhibitor for the treatment of SCCHN and are actively seeking partners for a combination program. In addition to our locally-administered TPTs, our pipeline also includes systemically-administered TPTs in development. Our systemically-administered TPTs are built around our proprietary de-immunized variant of the plant-derived cytotoxin bouganin, or deBouganin. Our lead systemically-administered product candidate, VB6-845d, is being developed for the treatment of multiple types of EpCAM-positive solid tumors. VB6-845d is administered by intravenous infusion. A Phase 1 clinical trial conducted with VB6-845, the prior version of VB6-845d, revealed no clinically relevant immune response to the deBouganin payload. We plan on submitting an IND with VB6-845d, once funding or a partner is secured for this program.
We have deferred further development of Proxinium and VB6-845d in order to focus our efforts and our resources on our ongoing development of Vicinium. We are also exploring collaboration agreements for Vicinium, Proxinium and VB6-845d.
Our locally-administered TPTs contain a targeting moiety that is designed to bind to EpCAM, which is a protein over expressed in many cancers. This targeting moiety is genetically fused to a truncated form of ETA, which is an immunogenic cytotoxic protein payload that is produced by the bacterial species, Pseudomonas. These product candidates are designed to bind to EpCAM on the surface of cancer cells. The TPT-EpCAM complex is subsequently internalized into the cell and, once inside the cell, the TPT is cleaved by a cellular enzyme to release the cytotoxic protein payload, thus enabling cancer cell-killing. We believe that our TPTs designed for local administration may not only directly kill cancer cells through a targeted delivery of a cytotoxic protein payload, but also potentiate an anti-cancer therapeutic immune response in cancer cells near the site of administration. This immune response is believed to be triggered by both the immunogenic cell death of the cancer cells due to our payload’s mechanism of action and the subsequent release of tumor antigens and the immunologically active setting created by the nature of the cytotoxic protein payloads.

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Our early pipeline product candidate, VB6-845d, was being developed for systemic administration as a treatment for multiple types of EpCAM-positive solid tumors. VB6-845d is a TPT consisting of an EpCAM targeting Fab genetically linked to deBouganin, a novel plant derived cytotoxic payload that we have optimized for minimal immunogenic potential.
We maintain global development, marketing and commercialization rights for all of our TPT-based product candidates. Upon regulatory approval for our product candidates, we will explore various commercialization strategies to market our products. If we obtain regulatory approval for Vicinium in high-grade NMIBC, we may build a North American specialty urology sales force to market the product or seek commercialization partners. If we obtain regulatory approval for our other product candidates, including Proxinium, we may seek partners with oncology expertise in order to maximize the commercial value of each asset or a portfolio of assets. We also own or exclusively license worldwide intellectual property rights for all of our TPT-based product candidates, covering our key patents with protection ranging from 2018 to 2036.
On June 10, 2016, we entered into a License Agreement, or the License Agreement, with F. Hoffmann-La Roche Ltd and Hoffmann-La Roche Inc., or collectively, Roche, pursuant to which we licensed our monoclonal antibody EBI-031agreed to, as promptly as reasonably practicable and all other IL-6 antagonist antibody technology owned by us. Underin any event within 60 days after the License Agreement, Roche is required to continue developing EBI-031 at its cost. At the timedate of the LicenseRegistration Rights Agreement, EBI-031, which was derived usingfile a registration statement on Form S-3 with the SEC covering the resale of the shares of common stock sold in the Private Placement, or the Registrable Subscription Securities. We will use our previous AMP-Rx platform, was in pre-clinical development as an intravitreal injectionreasonable best efforts to have the registration statement on Form S-3 declared effective by the SEC and maintain such effectiveness continuously for diabetic macular edemaa period up to the earlier of (i) three years from the date of the Registration Rights Agreement and uveitis. We(ii) the date that all Registrable Subscription Securities covered by the registration statement on Form S-3 have received $30.0 million in payments from Rochebeen sold or can be sold without restriction pursuant to Rule 144 promulgated by the LicenseSEC under the Securities Act, or SEC Rule 144, or another similar exemption under the Securities Act and without the requirement to be in compliance with subsection (c)(1) of SEC Rule 144 (or any successor thereto). The Registration Rights Agreement includingincludes customary indemnification rights in connection with the registration statement. We filed the registration statement on Form S-3, of which this prospectus forms a $7.5 million upfront payment and a $22.5 million milestone payment as a resultpart, to fulfill our contractual obligations under the Registration Rights Agreement.
The foregoing summary descriptions of the IND application for EBI-031 becoming effective. WeSubscription Agreement and the Registration Rights Agreement do not purport to be complete and are also entitledqualified in their entirety by reference to receive an additional $240.0 million upon the achievementfull text of other specified regulatory, developmentsuch documents, which are filed as exhibits to the registration statement of which this prospectus is a part and commercial milestones,are incorporated by reference herein.
The table below sets forth, to our knowledge, information concerning the beneficial ownership of shares of our common stock by the selling stockholders after closing of the Merger as of March 7, 2023. The information in the table below with respect to the selling stockholders has been obtained from the selling stockholders. When we refer to the “selling stockholders” in this prospectus, we mean the selling stockholders listed in the table below as offering shares, as well as royaltiestheir respective transferees, pledgees or donees or other successors-in-interest. The selling stockholders may sell all, some or none of the shares of common stock subject to this prospectus. See “Plan of Distribution.”
The number of shares of common stock beneficially owned prior to the offering for each selling stockholder includes (i) all shares of common stock held by such selling stockholder as of March 7, 2023, (ii) all shares as to which such selling stockholder has the right to acquire within 60 days of March 7, 2023 and (iii) all shares of common stock purchased by such selling stockholder in the Private Placement. The percentages of shares owned before and after the offering are based on net sales40,254,666 shares of potential future products containing EBI-031 orcommon stock outstanding as of March 7, 2023, which includes the outstanding shares of common stock offered by this prospectus. In computing the number of shares of common stock beneficially owned by a person and the percentage ownership of that person, we deemed outstanding shares of common stock issuable upon the exercise of options held by that selling stockholder that are exercisable within 60 days of March 7, 2023. We did not deem these shares outstanding, however, for the purpose of computing the percentage ownership of any other potential future products containing other IL-6 compounds.person.
Beneficial ownership is determined in accordance with the rules of the SEC and includes voting or investment power with respect to shares. Unless otherwise indicated below, to our knowledge, each selling stockholder named in the table has sole voting and investment power with respect to the shares of common

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stock beneficially owned by it, except to the extent authority is shared by spouses under applicable law. The inclusion of any shares in this table does not constitute an admission of beneficial ownership for any selling stockholder named below.
​​​
Shares of
Common Stock
Beneficially
Owned Prior
to Offering
​​
Number of
Shares of
Common Stock
Being
Offered
​​
Shares of
Common Stock
to be
Beneficially Owned
After Offering(1)
​
Name of Selling Stockholder​​Number​​Percentage​​Number​​Percentage​
Healthcap VII L.P.(2)
​​​​3,398,248​​​​​8.44%​​​​​575,907​​​​​2,822,341​​​​​7.01%​​
AbbVie Biotechnology Ltd.(3)
​​​​2,749,855​​​​​6.83%​​​​​462,674​​​​​2,287,181​​​​​5.68%​​
Wellington Life Sciences V GmbH & Co. KG(4)
​​​​2,297,546​​​​​5.71%​​​​​401,795​​​​​1,895,751​​​​​4.71%​​
Symbiosis II, LLC(5)
​​​​2,215,877​​​​​5.50%​​​​​389,620​​​​​1,826,257​​​​​4.54%​​
The Trustees of the University of Pennsylvania(6)
​​​​2,182,812​​​​​5.42%​​​​​340,917​​​​​1,841,895​​​​​4.58%​​
TPG Biotechnology Partners V L.P.(7)
​​​​1,684,062​​​​​4.18%​​​​​85,229​​​​​1,598,833​​​​​3.97%​​
MRL Ventures Fund LLC(8)
​​​​1,473,240​​​​​3.66%​​​​​304,390​​​​​1,168,850​​​​​2.90%​​
Agent Capital Fund I LP(9)
​​​​1,126,241​​​​​2.80%​​​​​91,317​​​​​1,034,924​​​​​2.57%​​
Aju Life Science 3.0 Venture Fund(10)
​​​​718,332​​​​​1.78%​​​​​109,580​​​​​608,752​​​​​1.51%​​
Livzon International Ventures I(11)
​​​​718,332​​​​​1.78%​​​​​109,580​​​​​608,752​​​​​1.51%​​
Pictet Thematic Private Equity, SICAV-RAIF – Pictet Thematic Private Equity – Health Fund I(12)
​​​​669,660​​​​​1.66%​​​​​669,660​​​​​—​​​​​—​​
b-to-v Partners S.à r.l.(13)
​​​​654,001​​​​​1.62%​​​​​109,580​​​​​544,421​​​​​1.35%​​
4BIO Ventures II LP(14)
​​​​445,628​​​​​1.11%​​​​​80,359​​​​​365,269​​​​​*​​
​
*
Less than 1%
​
(1)
We also previously investeddo not know when or in what amounts a significant portionselling stockholder may offer shares for sale. The selling stockholders might not sell any or might sell all of the shares offered by this prospectus. Because the selling stockholders may offer all or some of the shares pursuant to this offering, and because there are currently no agreements, arrangements or understandings with respect to the sale of any of the shares, we cannot estimate the number of the shares that will be held by the selling stockholders after completion of the offering. However, for purposes of this table, we have assumed that, after completion of the offering, none of the shares covered by this prospectus will be held by the selling stockholders.
​
(2)
Consists of (i) 575,907 shares issued to Healthcap VII L.P. in the Private Placement and (ii) 2,822,341 additional shares held by Healthcap VII L.P. HealthCap VII GP SA, a Swiss registered L.C.C., is the sole general partner of HealthCap VII, L.P. and has voting and investment control over the shares. HealthCap VII GP SA disclaims beneficial ownership of all shares held by HealthCap VII L.P., except to the extent of their pecuniary interest therein. Fabrice Bernhard is the General Manager of HealthCap VII GP SA. Dag Richter, Daniel Schafer and Frans Wuite are each Directors of HealthCap VII GP SA. Each of Messrs. Bernhard, Richter, Schafer and Wuite may be deemed to share voting and investment power with respect to the shares held by HealthCap VII L.P. and disclaim beneficial ownership of all shares held by HealthCap VII L.P., except to the extent of their pecuniary interest therein. Björn Odlander is a Managing Partner of VII Advisor AB, an affiliate of Healthcap VII L.P., and is a member of our efforts and financial resourcesboard of directors. Dr. Odlander disclaims beneficial ownership of all shares held by HealthCap VII L.P. except to the extent of his pecuniary interest therein, if any. The business address of HealthCap VII L.P. is c/o HealthCap VII GP SA, Avenue Villamont 23, CH 1005 Lausanne Switzerland.
​
(3)
Consists of (i) 462,674 shares issued to AbbVie Biotechnology Ltd. in the developmentPrivate Placement and (ii) 2,287,181 additional shares held by AbbVie Biotechnology Ltd. AbbVie Biotechnology Ltd. holds voting and investment control over the shares. The Board of Directors of AbbVie Biotechnology Ltd. consists of Lindsey Bristow, Jonathan C. Clipper, Stephen Muldoon and Arthur Price. Each of Ms. Bristow and each of Messrs. Clipper, Muldoon and Price may be deemed to share voting and
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investment power with respect to the shares held by AbbVie Biotechnology Ltd. and disclaim beneficial ownership of all shares held by AbbVie Biotechnology Ltd., except to the extent of their pecuniary interest therein, if any. The business address of AbbVie Biotechnology Ltd. is Thistle House, 4 Burnaby Street, Hamilton HM 11, Bermuda.
(4)
Consists of (i) 401,795 shares issued to Wellington Life Sciences V GmbH & Co. KG, or the Wellington Fund, in the Private Placement and (ii) 1,895,751 additional shares held by the Wellington Fund. The Wellington Fund is represented by Wellington Life Sciences Venture Capital Consulting GmbH, or the Wellington General Partner. The Wellington General Partner holds voting and investment control over the shares. Dr. Regina Hodits and Dr. Rainer Strohmenger, in their functions as managing directors of the Wellington General Partner, have individual signatory power as well as voting and/or investment control over the shares. Dr. Regina Hodits is a member of our product candidate isunakinra (EBI-005)board of directors. Dr. Regina Hodits disclaims beneficial ownership of all shares held by the Wellington Fund except to the extent of her pecuniary interest therein, if any. The business address of the Wellington Fund and the Wellington General Partner is Tuerkenstrasse 5, 80333 Munich, Germany.
​
(5)
Consists of (i) 389,620 shares issued to Symbiosis II, LLC in the Private Placement and (ii) 1,826,257 additional shares held by Symbiosis II, LLC, which exercises voting and investment control of the shares. Chidozie Ugwumba is the Managing Partner of Symbiosis II, LLC and as such has sole voting and investment control over the shares. Mr. Ugwumba is also a member of our board of directors. The business address of Symbiosis II, LLC is 609 S.W. 8th Street, Suite 365, Bentonville, Arkansas 72712.
​
(6)
Consists of (i) 340,917 shares issued to The Trustees of the University of Pennsylvania in the Private Placement and (ii) 1,841,895 additional shares held by The Trustees of the University of Pennsylvania. The Board of Trustees of the University of Pennsylvania has voting and dispositive power over the shares. The Board of Trustees of the University of Pennsylvania is comprised of more than three individuals who have authority over the voting and disposition of the shares. A business address of The Trustees of the University of Pennsylvania is 2929 Walnut Street, Suite 300, Philadelphia, Pennsylvania 19104.
​
(7)
Consists of (i) 85,229 shares issued to TPG Biotechnology Partners V, L.P., a Delaware limited partnership, in the Private Placement and (ii) 1,598,833 additional shares held by TPG Biotechnology Partners V, L.P. The general partner of TPG Biotechnology Partners V, L.P. is TPG Biotechnology GenPar V, L.P., a Delaware limited partnership, whose general partner is TPG Biotech GenPar V Advisors, LLC, a Delaware limited liability company, whose sole member is TPG Operating Group I, L.P., a Delaware limited partnership, whose general partner is TPG Holdings I-A, LLC, a Delaware limited liability company, whose managing member is TPG GPCo, LLC, a Delaware limited liability company, whose managing member is TPG Inc., a Delaware corporation, whose shares of Class B common stock (which represent a majority of the combined voting power of the common stock) are held by TPG Group Holdings (SBS), L.P., a Delaware limited partnership, whose general partner is TPG Group Holdings (SBS) Advisors, LLC, a Delaware limited liability company, whose managing member is TPG GP A, LLC, a Delaware limited liability company, which is owned by entities owned by David Bonderman, James G. Coulter and Jon Winkelried. Messrs. Bonderman, Coulter and Winkelried may therefore be deemed to share voting and investment power with respect to, and thus beneficially own the securities directly held by TPG Biotechnology Partners V, L.P. Messrs. Bonderman, Coulter and Winkelried disclaim beneficial ownership of the securities directly held by TPG Biotechnology Partners V, L.P. except to the extent of their pecuniary interest therein. The address of each of TPG GP A, LLC and Messrs. Bonderman, Coulter and Winkelried is 301 Commerce Street, Suite 3300, Fort Worth, Texas 76102.
​
(8)
Consists of (i) 304,390 shares issued to MRL Ventures Fund LLC in the Private Placement and (ii) 1,168,850 additional shares held by MRL Ventures Fund LLC. MRL Ventures Fund, LLC holds investment and voting control over the shares. Peter Dudek, Sunil Patel, Dean Li, Caroline Litchfield, Eliav Barr and George Adonna are members of the investment committee of MRL Ventures Fund, LLC. Each of Messrs. Dudek, Patel, Li, Miletich, Litchfield, Barr and Adonna may be deemed to share voting and investment power with respect to the shares held by MRL Ventures Fund, LLC and disclaim beneficial ownership of all shares held by MRL Ventures Fund, LLC, except to the extent of their pecuniary interest therein. The business address of MRL Ventures Fund, LLC is One Merck Drive, Whitehouse Station, New Jersey 08889.
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(9)
Consists of (i) 91,317 shares issued to Agent Capital Fund I LP in the Private Placement and (ii) 1,034,924 additional shares held by Agent Capital Fund I LP. Agent Capital Fund I LP is a Delaware limited partnership whose general partner is Agent Capital Fund I GP, LLC, or ACGPI, a Delaware limited liability company. Geeta Vemuri is the managing member of ACGPI and exercises voting and investment power with respect to the shares owned by Agent Capital Fund I LP. ACGPI and Ms. Vemuri disclaim beneficial ownership of all shares held by Agent Capital Fund I LP, except to the extent of their respective pecuniary interests therein. The address of each of Agent Capital Fund I LP, ACGPI and Ms. Vemuri is 1400 Main Street, Floor 1, Waltham, MA 02451.
​
(10)
Consists of (i) 109,580 shares issued to Aju Life Science 3.0 Venture Fund in the Private Placement and (ii) 608,752 additional shares held by Aju Life Science 3.0 Venture Fund. Aju IB Investment is the general partner of Aju Life Science 3.0 Venture Fund, and Solasta Ventures is a subsidiary of Aju IB Investment. Derek Yoon in his capacity as President and Chief Executive Officer of Solasta Ventures and Ji-won Kim in his capacity as Chief Executive Officer of Aju IB Investment have sole voting and investment control over the shares. Mr. Yoon and Mr. Kim. disclaim beneficial ownership of all shares held by Aju Life Science 3.0 Venture Fund, except to the extent of their pecuniary interest therein, if any. The address of Aju Life Science 3.0 Venture Fund is 201 Teheran-ro, Floor, Gangnam-gu, Seoul, Korea 06141.
​
(11)
Consists of (i) 109,580 shares issued to Livzon International Ventures I in the Private Placement and (ii) 608,752 additional shares held by Livzon International Ventures I. Livzon Pharmaceutical Group Inc. (SHE: 000513, HK: 01513), whose outstanding shares are publicly-held and listed on the Shenzhen Stock Exchange and the HongKong Stock Exchange, wholly owns Livzon International Ventures I. The address of Livzon International Ventures I is PO Box 309, Ugland House, Grand Cayman, KY1-1104, Cayman Islands.
​
(12)
Consists of shares issued to Pictet Thematic Private Equity, SICAV-RAIF — Pictet Thematic Private Equity — Health Fund I, or Pictet, in the Private Placement. Jens Hoellermann, Francesco Ilardi, Aurélien Favier and Yves Kuhn may be deemed to have voting and dispositive power over the shares held by Pictet . The address for each of Messrs. Jens Hoellermann, Francesco Ilardi, Aurélien Favier and Yves Kuhn is 15 Avenue J.F. Kennedy, L-1855 Luxembourg.
​
(13)
Consists of (i) 109,580 shares issued to b-to-v Partners S.à r.l. in the treatmentPrivate Placement and (ii) 544,421 additional shares held by b-to-v Partners S.à r.l. Dr. Christian Schütz and Florian Schweitzer, each in their capacity as Managing Directors of subjectsb-to-v Partners S.à r.l., have sole voting and investment control over the shares. Dr. Schütz and Mr. Schweitzer disclaim beneficial ownership of all shares held by b-to-v Partners S.à r.l., except to the extent of their pecuniary interest therein, if any. The address of b-to-v Partners S.à r.l. is 1c, rue Gabriel Lippmann, 5365 Munsbach, Luxembourg.
​
(14)
Consists of (i) 80,359 shares issued to 4BIO Ventures II LP in the Private Placement and (ii) 365,269 additional shares held by 4BIO Ventures II LP. 4BIO Ventures II GP Ltd, the general partner of 4BIO Ventures II LP, has voting and investment control with dry eye diseaserespect to the shares. Andrey Kozlov, Dmitry Kuzmin and allergic conjunctivitis. Based on negative results fromKieran Mudryy in their functions as directors of 4BIO Ventures II GP Ltd, have individual signatory power as well as voting and/or investment control over the shares. The address of 4BIO Ventures II LP is 78 Pall Mall, London SW1Y 5ES United Kingdom.
​
Relationships with Selling Stockholders
Board of Directors
Björn Odlander, who is a member of our completed Phase 3 clinical trials in dry eye diseaseboard of directors, is Managing Partner of HealthCap VII Advisor AB, an affiliate of Healthcap VII L.P., which is a selling stockholder. Chidozie Ugwumba, who is a member of our board of directors, is the Managing Partner of Symbiosis II, LLC, which is a selling stockholder. Dr. Regina Hodits, who is a member of our board of directors, is a director of Wellington General Partner, an affiliate of the Wellington Fund, which is a selling stockholder. Margarita Chavez, who was a former director of Legacy Carisma until March 7, 2023, is employed as a Managing Director of AbbVie Ventures, an affiliate of AbbVie Biotechnology Ltd., which is a selling stockholder.
Series A Convertible Preferred Stock Financing
In June 2018, November 2018 and allergic conjunctivitis, we do not plan to pursue further development of isunakinra.
Corporate Information
We were incorporatedMarch 2020, Legacy Carisma and CARISMA Therapeutics S.à r.l., a société à responsabilité limitée organized under the laws of Luxembourg and a subsidiary of Legacy

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Carisma, or Carisma Europe, as applicable, issued and sold an aggregate of 5,201,017 shares of the stateLegacy Carisma Series A preferred stock, $0.0001 par value per share and an aggregate of Delaware on937,501 Class B Shares, with a nominal value of one tenth of one eurocent (EUR 0.001), of Carisma Europe, or the Class B exchangeable shares, of which (i) 4,701,925 shares of Series A preferred stock and all of the Class B exchangeable shares were sold at a price per share of $10.40 in cash, for an aggregate purchase price of $58,650,030.40 and (ii) 499,092 shares of Legacy Carisma Series A preferred stock were sold at a price per share of $8.06 against payment by cancellation or conversion of indebtedness of Legacy Carisma to the applicable purchaser, including interest. Legacy Carisma also issued one share of Special Voting Preferred Stock of Legacy Carisma, $0.0001 par value per share, to the holder of the Class B exchangeable shares, which share was automatically cancelled when the Class B exchangeable shares were exchanged for capital stock of Legacy Carisma immediately prior to the effective time of the Merger. All of the shares of Legacy Carisma preferred stock held by the selling stockholders were exchanged for shares of the Company’s common stock at the effective time of the Merger. The following selling stockholders participated in the Series A convertible preferred stock financing: AbbVie Biotechnology Ltd., Agent Capital Fund I LP, b-to-v Partners S.à r.l., Healthcap VII L.P., MRL Ventures Fund LLC, The Trustees of the University of Pennsylvania, TPG Biotechnology Partners V L.P. and Wellington Life Sciences V GmbH & Co. KG.
Series B Convertible Preferred Stock Financing
In December 2020 and February 25, 2008 under2021, Legacy Carisma and Carisma Europe, as applicable, issued and sold an aggregate of 3,499,866 shares of the name NewCo LS14, Inc. We subsequently changed our nameLegacy Carisma Series B preferred stock, $0.0001 par value per share and an aggregate of 297,764 Class B-1 Shares, with a nominal value of one tenth of one eurocent (EUR 0.001), of Carisma Europe, or the Class B-1 exchangeable shares, all of which were sold at a price per share of $15.60 in cash, for an aggregate purchase price of $59,243,028.00. Legacy Carisma also issued one share of Legacy Carisma Series B special voting preferred stock, $0.0001 par value per share, to DeNovo Therapeutics, Inc.the holder of the Class B-1 exchangeable shares, which share was automatically cancelled when the Class B-1 exchangeable shares were exchanged for capital stock of Legacy Carisma immediately prior to the effective time of the Merger. All of the shares of Legacy Carisma preferred stock held by the selling stockholders were exchanged for shares of the Company’s common stock at the effective time of the Merger. The following selling stockholders participated in September 2008the Series B convertible preferred stock financing: 4BIO Ventures II LP, AbbVie Biotechnology Ltd., Agent Capital Fund I LP, Aju Life Science 3.0 Venture Fund, b-to-v Partners S.à r.l., Healthcap VII L.P., Livzon International Ventures I, MRL Ventures Fund LLC, Symbiosis II, LLC, The Trustees of the University of Pennsylvania, TPG Biotechnology Partners V L.P. and againWellington Life Sciences V GmbH & Co. KG.
Investor Rights Agreement
In December 2020, Legacy Carisma and Carisma Europe entered into an amended and restated investor rights agreement, or the Investor Rights Agreement, with certain holders of Legacy Carisma common stock, the Series A preferred stock, Series B preferred stock, Class B exchangeable shares and Class B-1 exchangeable shares, including certain holders of 5% of Legacy Carisma’s capital stock, and including certain affiliates of Legacy Carisma’s directors and their affiliates. The Investor Rights Agreement provided such holders with certain registration rights, including the right to Eleven Biotherapeutics, Inc.demand that Legacy Carisma file a registration statement or request that their shares be covered by a registration statement that Legacy Carisma is otherwise filing. The Investor Rights Agreement also provided certain major investors with certain information and observer rights. The Investor Rights Agreement was terminated in connection with the closing of the Merger. The following selling stockholders were party to the Investor Rights Agreement: 4BIO Ventures II LP, AbbVie Biotechnology Ltd., Agent Capital Fund I LP, Aju Life Science 3.0 Venture Fund, b-to-v Partners S.à r.l., Healthcap VII L.P., Livzon International Ventures I, MRL Ventures Fund LLC, Symbiosis II, LLC, The Trustees of the University of Pennsylvania, TPG Biotechnology Partners V L.P. and Wellington Life Sciences V GmbH & Co. KG.
Voting Agreement
In December 2020, Legacy Carisma and Carisma Europe entered into an amended and restated voting agreement, or the Voting Agreement, with certain holders of Legacy Carisma common stock, Series A preferred stock, Series B preferred stock, Class B exchangeable shares and Class B-1 exchangeable shares,

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including certain holders of 5% of Legacy Carisma’s capital stock, and including certain of Legacy Carisma’s directors and their affiliates. Pursuant to the Voting Agreement, such holders party thereto agreed to vote their shares in favor of the election of certain directors and specified transactions approved by the requisite majority of the shares of voting capital stock held by such holders. The Voting Agreement was terminated in connection with the closing of the Merger. The following selling stockholders were party to the Voting Agreement: 4BIO Ventures II LP, AbbVie Biotechnology Ltd., Agent Capital Fund I LP, Aju Life Science 3.0 Venture Fund, b-to-v Partners S.à r.l., Healthcap VII L.P., Livzon International Ventures I, MRL Ventures Fund LLC, Symbiosis II, LLC, The Trustees of the University of Pennsylvania, TPG Biotechnology Partners V L.P. and Wellington Life Sciences V GmbH & Co. KG.
Right of First Refusal and Co-Sale Agreement
In December 2020, Legacy Carisma entered into an amended and restated right of first refusal and co-sale agreement, or the ROFR Agreement, with certain holders of Legacy Carisma common stock, the Series A preferred stock, Series B preferred stock, Class B exchangeable shares and Class B-1 exchangeable shares, including certain holders of 5% of its capital stock, and including certain of Legacy Carisma’s directors and their affiliates. Pursuant to the ROFR Agreement, Legacy Carisma had a right of first refusal in respect of certain sales of securities by certain holders of its capital stock. To the extent Legacy Carisma did not exercise such right in full, certain holders of its capital stock were granted certain rights of first refusal and co-sale in respect of such sales. The ROFR Agreement was terminated in connection with the closing of the Merger. The following selling stockholders were party to the ROFR Agreement: 4BIO Ventures II LP, AbbVie Biotechnology Ltd., Agent Capital Fund I LP, Aju Life Science 3.0 Venture Fund, b-to-v Partners S.à r.l., Healthcap VII L.P., Livzon International Ventures I, MRL Ventures Fund LLC, Symbiosis II, LLC, The Trustees of the University of Pennsylvania, TPG Biotechnology Partners V L.P. and Wellington Life Sciences V GmbH & Co. KG.
Share Exchange and Voting Agreement
In December 2020, Legacy Carisma and Carisma Europe entered into an amended and restated share exchange and voting agreement, or the Share Exchange Agreement, with certain holders of the Series A preferred stock, Series B preferred stock, Class B exchangeable shares and Class B-1 exchangeable shares, including certain holders of 5% of its capital stock, and including certain of Legacy Carisma’s directors and their affiliates. The Share Exchange Agreement provided for the exchange of the Class B exchangeable shares and Class B-1 exchangeable shares for shares of Series A preferred stock and Series B preferred stock, respectively, either voluntarily or automatically, upon certain circumstances as set forth therein. In connection with the closing of the Merger, the Class B exchangeable shares and Class B-1 exchangeable shares were exchanged into Legacy Carisma preferred stock, and the Share Exchange Agreement terminated. The following selling stockholders were party to the Share Exchange Agreement: 4BIO Ventures II LP, AbbVie Biotechnology Ltd., Agent Capital Fund I LP, Aju Life Science 3.0 Venture Fund, b-to-v Partners S.à r.l., Healthcap VII L.P., Livzon International Ventures I, MRL Ventures Fund LLC, Symbiosis II, LLC, The Trustees of the University of Pennsylvania, TPG Biotechnology Partners V L.P. and Wellington Life Sciences V GmbH & Co. KG.
University of Pennsylvania License Agreement
In November 2017, Legacy Carisma entered into a license agreement with the Trustees of the University of Pennsylvania, or Penn, which was amended in February 2010. Our principal executive offices are located at 245 First Street, Suite 1800, Cambridge, Massachusetts 02142,2018, January 2019, March 2020 and June 2021, or the Penn License Agreement. Pursuant to the Penn License Agreement, Legacy Carisma is responsible for paying Penn an annual license maintenance fee in the low tens of thousands of dollars, payable until Legacy Carisma’s first payment of a royalty. Legacy Carisma is required to pay Penn up to $10.9 million per product in development and regulatory milestone payments, up to $30.0 million per product in commercial milestone payments, and up to an additional $1.7 million in development and regulatory milestone payments for the first CAR-M product directed to mesothelin. As of April 17, 2023, Penn is a holder of 5% or more of our telephone numbervoting securities and a selling stockholder.

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DESCRIPTION OF CAPITAL STOCK
The following description of our capital stock is (617) 444-8550. Our website address is www.elevenbio.com. The information contained on, or that can be accessed through, our websiteintended as a summary only and therefore is not a part of this prospectus. We have included our website address in this prospectus solely as an inactive textual reference.
Eleven Biotherapeutics, Viventia Bio and the Viventia and Eleven logos are our trademarks. The other trademarks, trade names and service marks appearing in this prospectus are the property of their respective owners.
Implications of Being an Emerging Growth Company
We are an “emerging growth company,” as defined in the Jumpstart Our Business Startups Act of 2012, or the JOBS Act. We will remain an emerging growth company until the earliest of (1) the last day of the fiscal year following the fifth anniversarycomplete description of our initial public offering, or December 31, 2019, (2) the last day of the fiscal year after our annual gross revenuecapital stock. This description is $1.07 billion or more, (3) the date on which we have, during the previous three-year period, issued more than $1.0 billion in non-convertible debt securitiesbased upon, and (4) the last day of any fiscal year in which the market value of our common stock held by non-affiliates exceeded $700 million as of the end of the second quarter of that fiscal year.
For as long as we remain an “emerging growth company,” we may take advantage of certain exemptions from various reporting requirements that are applicable to public companies that are not “emerging growth companies” including,

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but not limited to, not being required to comply with the auditor attestation requirements of Section 404 of the Sarbanes-Oxley Act, reduced disclosure obligations regarding executive compensation and financial statements in our periodic reports and proxy statements, and exemptions from the requirements of holding a nonbinding advisory vote to approve executive compensation and shareholder approval of any golden parachute payments not previously approved. We may take advantage of one or more of these reporting exemptions until we are no longer an “emerging growth company.”
The JOBS Act provides that an “emerging growth company” can take advantage of an extended transition period for complying with new or revised accounting standards. We have irrevocably elected not to avail ourselves of this exemption and, therefore, we are subject to the same new or revised accounting standards as other public companies that are not “emerging growth companies.”

RISK FACTORS
Our business is influenced by many factors that are difficult to predict, and that involve uncertainties that may materially affect actual operating results, cash flows and financial condition. Before making an investment decision, you should carefully consider these risks, including those set forth in the “Risk Factors” section of our most recent Annual Report on Form 10-K filed with the SEC, as revised or supplemented by our Quarterly Reports on Form 10-Q filed with the SEC since the filing of our most recent Annual Report on Form 10-K, each of which is incorporatedqualified by reference into this prospectus.to, our Restated Certificate of Incorporation, or certificate of incorporation, our Amended and Restated By-laws, or by-laws, and applicable provisions of Delaware corporate law. You should also carefully consider any other information we include or incorporate by reference in this prospectus or include in any applicable prospectus supplement. Eachread our certificate of the risks described in these sectionsincorporation and documents could materially and adversely affect our business, financial condition, results of operations and prospects, and could result in a partial or complete loss of your investment.

USE OF PROCEEDS
Unless otherwise indicated in a prospectus supplement or free writing prospectus, we anticipate that the net proceeds from our sale of any securities will be used to fund the ongoing clinical development of Vicinium and for general corporate purposes,by-laws, which may include capital expenditures and funding our working capital needs. We expect from time to time to evaluate the acquisition of businesses, products and technologies for which a portion of the net proceeds may be used, although we currently are not planning or negotiating any such transactions. Pending such uses, we may invest the net proceeds in investment grade interest-bearing securities.
The amounts actually expended for each purpose may vary significantly depending upon numerous factors, including the amount and timing of the proceeds from any sale of securities. Expenditures will also depend upon the establishment of collaborative arrangements with other companies, the availability of additional financing and other factors. Investors will be relying on the judgment of our management regarding the application of the proceeds of any sale of securities.

RATIO OF EARNINGS TO FIXED CHARGES
Any time debt securities are offered pursuant to this prospectus, we will provide a table setting forth our ratio of earnings to fixed charges on a historical basis in the applicable prospectus supplement, if required.

DESCRIPTION OF OUR DEBT SECURITIES
We may offer debt securities which may be senior or subordinated. We refer to the senior debt securities and the subordinated debt securities collectivelyfiled as debt securities. The following description summarizes the general terms and provisions of the debt securities. We will describe the specific terms of the debt securities and the extent, if any, to which the general provisions summarized below apply to any series of debt securities in the prospectus supplement relating to the series and any applicable free writing prospectus that we authorize to be delivered. When we refer to

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“the Company,” “we,” “our,” and “us” in this section, we mean Eleven Biotherapeutics, Inc. excluding, unless the context otherwise requires or as otherwise expressly stated, our subsidiaries.
We may issue senior debt securities from time to time, in one or more series under a senior indenture to be entered into between us and a senior trustee to be named in a prospectus supplement, which we refer to as the senior trustee. We may issue subordinated debt securities from time to time, in one or more series under a subordinated indenture to be entered into between us and a subordinated trustee to be named in a prospectus supplement, which we refer to as the subordinated trustee. Together, the senior indenture and the subordinated indenture are referred to as the indentures and, together, the senior trustee and the subordinated trustee are referred to as the trustees. This prospectus briefly outlines some of the provisions of the indentures. The following summary of the material provisions of the indentures is qualified in its entirety by the provisions of the indentures, including definitions of certain terms used in the indentures. Wherever we refer to particular sections or defined terms of the indentures, those sections or defined terms are incorporated by reference in this prospectus or the applicable prospectus supplement. You should review the indentures that are incorporated by referenceexhibits to the registration statement of which this prospectus forms a part, for additional information.
None of the indentures will limit the amount of debt securities that we may issue. The applicable indenture will provide that debt securities may be issued up to an aggregate principal amount authorized from time to time by us and may be payable in any currency or currency unit designated by us or in amounts determined by reference to an index.
General
The senior debt securities will constitute our unsecured and unsubordinated general obligations and will rank pari passu with our other unsecured and unsubordinated obligations. The subordinated debt securities will constitute our unsecured and subordinated general obligations and will be junior in right of payment to our senior indebtedness (including senior debt securities), as described under the heading “—Certain Terms of the Subordinated Debt Securities—Subordination.” The debt securities will be structurally subordinated to all existing and future indebtedness and other liabilities of our subsidiaries unless such subsidiaries expressly guarantee such debt securities.
The debt securities will be our unsecured obligations. Any secured debt or other secured obligations will be effectively senior to the debt securities to the extent of the value of the assets securing such debt or other obligations.
The applicable prospectus supplement and/or free writing prospectus will include any additional or different terms of the debt securities of any series being offered, including the following terms:
the title and type of the debt securities;
whether the debt securities will be senior or subordinated debt securities, and, with respect to debt securities issued under the subordinated indenture the terms on which they are subordinated;
the aggregate principal amount of the debt securities;
the price or prices at which we will sell the debt securities;
the maturity date or dates of the debt securities and the right, if any, to extend such date or dates;
the rate or rates, if any, per year, at which the debt securities will bear interest, or the method of determining such rate or rates;
the date or dates from which such interest will accrue, the interest payment dates on which such interest will be payable or the manner of determination of such interest payment dates and the related record dates;
the right, if any, to extend the interest payment periods and the duration of that extension;

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the manner of paying principal and interest and the place or places where principal and interest will be payable;
provisions for a sinking fund, purchase fund or other analogous fund, if any;
any redemption dates, prices, obligations and restrictions on the debt securities;
the currency, currencies or currency units in which the debt securities will be denominated and the currency, currencies or currency units in which principal and interest, if any, on the debt securities may be payable;
any conversion or exchange features of the debt securities;
whether and upon what terms the debt securities may be defeased;
any events of default or covenants in addition to or in lieu of those set forth in the indenture;
whether the debt securities will be issued in definitive or global form or in definitive form only upon satisfaction of certain conditions;
whether the debt securities will be guaranteed as to payment or performance;
any special tax implications of the debt securities; and
any other material terms of the debt securities.
When we refer to “principal” in this section with reference to the debt securities, we are also referring to “premium, if any.”
We may from time to time, without notice to or the consent of the holders of any series of debt securities, create and issue further debt securities of any such series ranking equally with the debt securities of such series in all respects (or in all respects other than (1) the payment of interest accruing prior to the issue date of such further debt securities or (2) the first payment of interest following the issue date of such further debt securities). Such further debt securities may be consolidated and form a single series with the debt securities of such series and have the same terms as to status, redemption or otherwise as the debt securities of such series.
You may present debt securities for exchange and you may present debt securities for transfer in the manner, at the places and subject to the restrictions set forth in the debt securities and the applicable prospectus supplement. We will provide you those services without charge, although you may have to pay any tax or other governmental charge payable in connection with any exchange or transfer, as set forth in the indenture.
Debt securities may bear interest at a fixed rate or a floating rate. Debt securities bearing no interest or interest at a rate that at the time of issuance is below the prevailing market rate (original issue discount securities) may be sold at a discount below their stated principal amount. U.S. federal income tax considerations applicable to any such discounted debt securities or to certain debt securities issued at par which are treated as having been issued at a discount for U.S. federal income tax purposes will be described in the applicable prospectus supplement.
We may issue debt securities with the principal amount payable on any principal payment date, or the amount of interest payable on any interest payment date, to be determined by reference to one or more currency exchange rates, securities or baskets of securities, commodity prices or indices. You may receive a payment of principal on any principal payment date, or a payment of interest on any interest payment date, that is greater than or less than the amount of principal or interest otherwise payable on such dates, depending on the value on such dates of the applicable currency, security or basket of securities, commodity or index. Information as to the methods for determining the amount of principal or interest payable on any date, the currencies, securities or baskets of securities, commodities or indices to which the

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amount payable on such date is linked and certain related tax considerations will be set forth in the applicable prospectus supplement.
Certain Terms of the Senior Debt Securities
Covenants.Unless we indicate otherwise in a prospectus supplement, the senior debt securities will not contain any financial or restrictive covenants, including covenants restricting either us or any of our subsidiaries from incurring, issuing, assuming or guaranteeing any indebtedness secured by a lien on any of our or our subsidiaries’ property or capital stock, or restricting either us or any of our subsidiaries from entering into sale and leaseback transactions.
Consolidation, Merger and Sale of Assets. Unless we indicate otherwise in a prospectus supplement, we may not consolidate with or merge into any other person, in a transaction in which we are not the surviving corporation, or convey, transfer or lease our properties and assets substantially as an entirety to any person, in either case, unless:
the successor entity, if any, is a U.S. corporation, limited liability company, partnership or trust (subject to certain exceptions provided for in the senior indenture);
the successor entity assumes our obligations on the senior debt securities and under the senior indenture;
immediately after giving effect to the transaction, no default or event of default shall have occurred and be continuing; and
certain other conditions are met.
No Protection in the Event of a Change in Control. Unless we indicate otherwise in a prospectus supplement with respect to a particular series of senior debt securities, the senior debt securities will not contain any provisions that may afford holders of the senior debt securities protection in the event we have a change in control or in the event of a highly leveraged transaction (whether or not such transaction results in a change in control).are important to you.
Events of Default. Unless we indicate otherwise in a prospectus supplement with respect to a particular series of senior debt securities, the following are events of default under the senior indenture for any series of senior debt securities:
failure to pay interest on any senior debt securities of such series when due and payable, if that default continues for a period of 30 days (or such other period as may be specified for such series);
failure to pay principal on the senior debt securities of such series when due and payable whether at maturity, upon redemption, by declaration or otherwise (and, if specified for such series, the continuance of such failure for a specified period);
default in the performance of or breach of any of our covenants or agreements in the senior indenture applicable to senior debt securities of such series, other than a covenant breach which is specifically dealt with elsewhere in the senior indenture, and that default or breach continues for a period of 90 days after we receive written notice from the trustee or from the holders of 25% or more in aggregate principal amount of the senior debt securities of such series;
certain events of bankruptcy or insolvency, whether or not voluntary; and
any other event of default provided for in such series of senior debt securities as may be specified in the applicable prospectus supplement.
The default by us under any other debt, including any other series of debt securities, is not a default under the senior indenture.

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If an event of default other than an event of default specified in the fourth bullet point above occurs with respect to a series of senior debt securities and is continuing under the senior indenture, then, and in each such case, either the trustee or the holders of not less than 25% in aggregate principal amount of such series then outstanding under the senior indenture (each such series voting as a separate class) by written notice to us and to the trustee, if such notice is given by the holders, may, and the trustee at the request of such holders shall, declare the principal amount of and accrued interest on such series of senior debt securities to be immediately due and payable, and upon this declaration, the same shall become immediately due and payable.
If an event of default specified in the fourth bullet point above occurs and is continuing, the entire principal amount of and accrued interest on each series of senior debt securities then outstanding shall become immediately due and payable.
Unless otherwise specified in the prospectus supplement relating to a series of senior debt securities originally issued at a discount, the amount due upon acceleration shall include only the original issue price of the senior debt securities, the amount of original issue discount accrued to the date of acceleration and accrued interest, if any.
Upon certain conditions, declarations of acceleration may be rescinded and annulled and past defaults may be waived by the holders of a majority in aggregate principal amount of all the senior debt securities of such series affected by the default, each series voting as a separate class. Furthermore, subject to various provisions in the senior indenture, the holders of a majority in aggregate principal amount of a series of senior debt securities, by notice to the trustee, may waive an existing default or event of default with respect to such senior debt securities and its consequences, except a default in the payment of principal of or interest on such senior debt securities or in respect of a covenant or provision of the senior indenture which cannot be modified or amended without the consent of the holders of each such senior debt security. Upon any such waiver, such default shall cease to exist, and any event of default with respect to such senior debt securities shall be deemed to have been cured, for every purpose of the senior indenture; but no such waiver shall extend to any subsequent or other default or event of default or impair any right consequent thereto.
The holders of a majority in aggregate principal amount of a series of senior debt securities may direct the time, method and place of conducting any proceeding for any remedy available to the trustee or exercising any trust or power conferred on the trustee with respect to such senior debt securities. However, the trustee may refuse to follow any direction that conflicts with law or the senior indenture, that may involve the trustee in personal liability or that the trustee determines in good faith may be unduly prejudicial to the rights of holders of such series of senior debt securities not joining in the giving of such direction and may take any other action it deems proper that is not inconsistent with any such direction received from holders of such series of senior debt securities. A holder may not pursue any remedy with respect to the senior indenture or any series of senior debt securities unless:
the holder gives the trustee written notice of a continuing event of default;
the holders of at least 25% in aggregate principal amount of such series of senior debt securities make a written request to the trustee to pursue the remedy in respect of such event of default;
the requesting holder or holders offer the trustee indemnity satisfactory to the trustee against any costs, liability or expense;
the trustee does not comply with the request within 60 days after receipt of the request and the offer of indemnity; and
during such 60-day period, the holders of a majority in aggregate principal amount of such series of senior debt securities do not give the trustee a direction that is inconsistent with the request.
These limitations, however, do not apply to the right of any holder of a senior debt security to receive payment of the principal of and interest on such senior debt security in accordance with the terms of such debt security, or to bring suit for the enforcement of any such payment in accordance with the terms of such debt security, on or after the due date for the senior debt securities, which right shall not be impaired or affected without the consent of the holder.

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The senior indenture requires certain of our officers to certify, on or before a fixed date in each year in which any senior debt security is outstanding, as to their knowledge of our compliance with all covenants, agreements and conditions under the senior indenture.
Satisfaction and Discharge. We can satisfy and discharge our obligations to holders of any series of debt securities if:
we pay or cause to be paid, as and when due and payable, the principal of and any interest on all senior debt securities of such series outstanding under the senior indenture; or
all senior debt securities of such series have become due and payable or will become due and payable within one year (or are to be called for redemption within one year) and we deposit in trust a combination of cash and U.S. government or U.S. government agency obligations that will generate enough cash to make interest, principal and any other payments on the debt securities of that series on their various due dates.
Under current U.S. federal income tax law, the deposit and our legal release from the debt securities would be treated as though we took back your debt securities and gave you your share of the cash and debt securities or bonds deposited in trust. In that event, you could recognize gain or loss on the debt securities you give back to us. Purchasers of the debt securities should consult their own advisers with respect to the tax consequences to them of such deposit and discharge, including the applicability and effect of tax laws other than the U.S. federal income tax law.
Defeasance. Unless the applicable prospectus supplement provides otherwise, the following discussion of legal defeasance and discharge and covenant defeasance will apply to any series of debt securities issued under the indentures.
Legal Defeasance. We can legally release ourselves from any payment or other obligations on the debt securities of any series (called “legal defeasance”) if certain conditions are met, including the following:
We deposit in trust for your benefit and the benefit of all other direct holders of the debt securities of the same series a combination of cash and U.S. government or U.S. government agency obligations that will generate enough cash to make interest, principal and any other payments on the debt securities of that series on their various due dates.
There is a change in current U.S. federal income tax law or an IRS ruling that lets us make the above deposit without causing you to be taxed on the debt securities any differently than if we did not make the deposit and instead repaid the debt securities ourselves when due. Under current U.S. federal income tax law, the deposit and our legal release from the debt securities would be treated as though we took back your debt securities and gave you your share of the cash and debt securities or bonds deposited in trust. In that event, you could recognize gain or loss on the debt securities you give back to us.
We deliver to the trustee a legal opinion of our counsel confirming the tax law change or ruling described above.
If we accomplish legal defeasance, as described above, you would have to rely solely on the trust deposit for repayment of the debt securities. You could not look to us for repayment in the event of any shortfall.
Covenant Defeasance. Without any change of current U.S. federal tax law, we can make the same type of deposit described above and be released from some of the covenants in the debt securities (called “covenant defeasance”). In that event, you would lose the protection of those covenants but would gain the protection of having money and securities set aside in trust to repay the debt securities. In order to achieve covenant defeasance, we must do the following (among other things):
We must deposit in trust for your benefit and the benefit of all other direct holders of the debt securities of the same series a combination of cash and U.S. government or U.S. government agency obligations

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that will generate enough cash to make interest, principal and any other payments on the debt securities of that series on their various due dates.
We must deliver to the trustee a legal opinion of our counsel confirming that under current U.S. federal income tax law we may make the above deposit without causing you to be taxed on the debt securities any differently than if we did not make the deposit and instead repaid the debt securities ourselves when due.
If we accomplish covenant defeasance, you could still look to us for repayment of the debt securities if there were a shortfall in the trust deposit. In fact, if one of the events of default occurred (such as our bankruptcy) and the debt securities become immediately due and payable, there may be such a shortfall. Depending on the events causing the default, you may not be able to obtain payment of the shortfall.
Modification and Waiver. We and the trustee may amend or supplement the senior indenture or the senior debt securities without the consent of any holder:
to convey, transfer, assign, mortgage or pledge any assets as security for the senior debt securities of one or more series;
to evidence the succession of a corporation, limited liability company, partnership or trust to us, and the assumption by such successor of our covenants, agreements and obligations under the senior indenture or to otherwise comply with the covenant relating to mergers, consolidations and sales of assets;
to comply with requirements of the SEC in order to effect or maintain the qualification of the senior indenture under the Trust Indenture Act of 1939, as amended, or the Trust Indenture Act;
to add to our covenants such new covenants, restrictions, conditions or provisions for the protection of the holders, and to make the occurrence, or the occurrence and continuance, of a default in any such additional covenants, restrictions, conditions or provisions an event of default;
to cure any ambiguity, defect or inconsistency in the senior indenture or in any supplemental indenture or to conform the senior indenture or the senior debt securities to the description of senior debt securities of such series set forth in this prospectus or any applicable prospectus supplement;
to provide for or add guarantors with respect to the senior debt securities of any series;
to establish the form or forms or terms of the senior debt securities as permitted by the senior indenture;
to evidence and provide for the acceptance of appointment under the senior indenture by a successor trustee, or to make such changes as shall be necessary to provide for or facilitate the administration of the trusts in the senior indenture by more than one trustee;
to add to, delete from or revise the conditions, limitations and restrictions on the authorized amount, terms, purposes of issue, authentication and delivery of any series of senior debt securities;
to make any change to the senior debt securities of any series so long as no senior debt securities of such series are outstanding; or
to make any change that does not adversely affect the rights of any holder in any material respect.
Other amendments and modifications of the senior indenture or the senior debt securities issued may be made, and our compliance with any provision of the senior indenture with respect to any series of senior debt securities may be waived, with the consent of the holders of a majority of the aggregate principal amount of the outstanding senior debt securities

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of all series affected by the amendment or modification (voting together as a single class); provided, however, that each affected holder must consent to any modification, amendment or waiver that:
extends the final maturity of any senior debt securities of such series;
reduces the principal amount of any senior debt securities of such series;
reduces the rate or extends the time of payment of interest on any senior debt securities of such series;
reduces the amount payable upon the redemption of any senior debt securities of such series;
changes the currency of payment of principal of or interest on any senior debt securities of such series;
reduces the principal amount of original issue discount securities payable upon acceleration of maturity or the amount provable in bankruptcy;
waives an uncured default in the payment of principal of or interest on the senior debt securities (except in the case of a rescission of acceleration as described above);
changes the provisions relating to the waiver of past defaults or changes or impairs the right of holders to receive payment or to institute suit for the enforcement of any payment or conversion of any senior debt securities of such series on or after the due date therefor;
modifies any of the provisions of these restrictions on amendments and modifications, except to increase any required percentage or to provide that certain other provisions cannot be modified or waived without the consent of the holder of each senior debt security of such series affected by the modification; or
reduces the above-stated percentage of outstanding senior debt securities of such series whose holders must consent to a supplemental indenture or modifies or amends or waives certain provisions of or defaults under the senior indenture.
It shall not be necessary for the holders to approve the particular form of any proposed amendment, supplement or waiver, but it shall be sufficient if the holders’ consent approves the substance thereof. After an amendment, supplement or waiver of the senior indenture in accordance with the provisions described in this section becomes effective, the trustee must give to the holders affected thereby certain notice briefly describing the amendment, supplement or waiver. Any failure by the trustee to give such notice, or any defect therein, shall not, however, in any way impair or affect the validity of any such amendment, supplemental indenture or waiver.
No Personal Liability of Incorporators, Stockholders, Officers, Directors. The senior indenture provides that no recourse shall be had under any obligation, covenant or agreement of ours in the senior indenture or any supplemental indenture, or in any of the senior debt securities or because of the creation of any indebtedness represented thereby, against any of our incorporators, stockholders, officers or directors, past, present or future, or of any predecessor or successor entity thereof under any law, statute or constitutional provision or by the enforcement of any assessment or by any legal or equitable proceeding or otherwise. Each holder, by accepting the senior debt securities, waives and releases all such liability.
Concerning the Trustee. The senior indenture provides that, except during the continuance of an event of default, the trustee will not be liable except for the performance of such duties as are specifically set forth in the senior indenture. If an event of default has occurred and is continuing, the trustee will exercise such rights and powers vested in it under the senior indenture and will use the same degree of care and skill in its exercise as a prudent person would exercise under the circumstances in the conduct of such person’s own affairs.
The senior indenture and the provisions of the Trust Indenture Act incorporated by reference therein contain limitations on the rights of the trustee thereunder, should it become a creditor of ours or any of our subsidiaries, to obtain payment

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of claims in certain cases or to realize on certain property received by it in respect of any such claims, as security or otherwise. The trustee is permitted to engage in other transactions, provided that if it acquires any conflicting interest (as defined in the Trust Indenture Act), it must eliminate such conflict or resign.
We may have normal banking relationships with the senior trustee in the ordinary course of business.
Unclaimed Funds. All funds deposited with the trustee or any paying agent for the payment of principal, premium, interest or additional amounts in respect of the senior debt securities that remain unclaimed for two years after the date upon which such principal, premium or interest became due and payable will be repaid to us. Thereafter, any right of any holder of senior debt securities to such funds shall be enforceable only against us, and the trustee and paying agents will have no liability therefor.
Governing Law. The senior indenture and the senior debt securities will be governed by, and construed in accordance with, the internal laws of the State of New York.
Certain Terms of the Subordinated Debt Securities
Other than the terms of the subordinated indenture and subordinated debt securities relating to subordination or otherwise as described in the prospectus supplement relating to a particular series of subordinated debt securities, the terms of the subordinated indenture and subordinated debt securities are identical in all material respects to the terms of the senior indenture and senior debt securities.
Additional or different subordination terms may be specified in the prospectus supplement applicable to a particular series.
Subordination. The indebtedness evidenced by the subordinated debt securities is subordinate to the prior payment in full of all of our senior indebtedness, as defined in the subordinated indenture. During the continuance beyond any applicable grace period of any default in the payment of principal, premium, interest or any other payment due on any of our senior indebtedness, we may not make any payment of principal of or interest on the subordinated debt securities (except for certain sinking fund payments). In addition, upon any payment or distribution of our assets upon any dissolution, winding-up, liquidation or reorganization, the payment of the principal of and interest on the subordinated debt securities will be subordinated to the extent provided in the subordinated indenture in right of payment to the prior payment in full of all our senior indebtedness. Because of this subordination, if we dissolve or otherwise liquidate, holders of our subordinated debt securities may receive less, ratably, than holders of our senior indebtedness. The subordination provisions do not prevent the occurrence of an event of default under the subordinated indenture.
The term “senior indebtedness” of a person means with respect to such person the principal of, premium, if any, interest on, and any other payment due pursuant to any of the following, whether outstanding on the date of the subordinated indenture or incurred by that person in the future:
all of the indebtedness of that person for money borrowed;
all of the indebtedness of that person evidenced by notes, debentures, bonds or other securities sold by that person for money;
all of the lease obligations that are capitalized on the books of that person in accordance with generally accepted accounting principles;
all indebtedness of others of the kinds described in the first two bullet points above and all lease obligations of others of the kind described in the third bullet point above that the person, in any manner, assumes or guarantees or that the person in effect guarantees through an agreement to purchase, whether that agreement is contingent or otherwise; and

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all renewals, extensions or refundings of indebtedness of the kinds described in the first, second or fourth bullet point above and all renewals or extensions of leases of the kinds described in the third or fourth bullet point above;
unless, in the case of any particular indebtedness, renewal, extension or refunding, the instrument creating or evidencing it or the assumption or guarantee relating to it expressly provides that such indebtedness, renewal, extension or refunding is not superior in right of payment to the subordinated debt securities. Our senior debt securities constitute senior indebtedness for purposes of the subordinated debt indenture.

DESCRIPTION OF OUR CAPITAL STOCK
The following description of our capital stock and provisions of our certificate of incorporate, bylaws and the Delaware General Corporate Law, or DGCL, are summaries and are qualified in their entirety by reference to the certificate of incorporation and the bylaws. We have filed copies of these documents with the SEC as exhibits to our registration statement, of which this prospectus forms a part.
As of March 13, 2018, our authorized capital stock consists of 200,000,000100,000,000 shares of our common stock par value $0.001 per share, and 5,000,000 shares of our preferred stock, par value $0.001 per share, all of which preferred stock is undesignated.  As of March 13, 2018, we had 35,127,773 sharesstock.
Common Stock
Annual Meeting.   Annual meetings of our common stockstockholders are held on the date designated in accordance with our by-laws. Written notice must be mailed to each stockholder entitled to vote not less than ten nor more than 60 days before the date of the meeting. The presence in person or by proxy of the holders of record of a majority of our issued and outstanding shares entitled to vote at such meeting constitutes a quorum for the transaction of business at meetings of the stockholders. Special meetings of the stockholders may be called at any time only by the board of directors, stating the purpose of such meeting. Except as may be otherwise provided by applicable law, our certificate of incorporation or our by-laws, all elections shall be decided by a plurality, and all other questions shall be decided by a majority, of the votes cast by stockholders entitled to vote thereon at a duly held by 33meeting of stockholders of record. This number does not include beneficial owners whose shares were held in street name.at which a quorum is present.
Common Stock
HoldersVoting Rights.   Each holder of our common stock areis entitled to one vote for each share held of record on all matters submitted to a votebe voted upon by stockholders, including the election of stockholdersdirectors. Our certificate of incorporation and by-laws do not haveprovide for cumulative voting rights. Eachrights.Except as otherwise provided by law, our certificate of incorporation and by-laws, in all matters other than the election of directors, the affirmative vote of the majority of the shares present in person or represented by our stockholders willproxy at a meeting at which a quorum is present and entitled to vote on the subject matter shall be determinedthe act of the stockholders. Directors shall be elected by a plurality of the votes castshares present in person or represented by the stockholdersproxy at a meeting at which a quorum is present and entitled to vote on the election. Holderselection of directors.
Dividends.   Subject to the rights, powers and preferences of any outstanding preferred stock, and except as provided by law or in our certificate of incorporation, dividends may be declared and paid or set aside for payment on the common stock are entitledout of legally available assets or funds when and as declared by the board of directors. The payment of dividends is contingent upon our revenue and earnings, capital requirements, and general financial condition, as well as contractual restrictions and other considerations deemed to receive proportionately any dividends as may be declaredrelevant by our board of directors, subjectdirectors.
Liquidation, Dissolution and Winding Up.   Subject to any preferential dividendthe rights, powers and preferences of thenany outstanding preferred stock.
Instock, in the event of our liquidation, dissolution or dissolution,winding up, our net assets will be distributed pro rata to the holders of our common stock are entitled to receive proportionately all assets available for distribution to stockholders after the payment of all debts and other liabilities and subject to the prior rights of any of our then outstanding preferred stock.
Other Rights.
Holders of ourthe common stock have no preemptive, subscription, redemptionright to:
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convert the stock into any other security;
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have the stock redeemed;
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purchase additional stock; or conversion rights.
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maintain their proportionate ownership interest.
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Holders of shares of the common stock are not required to make additional capital contributions.
Transfer Agent and Registrar.   Computershare Trust Company, N.A. is transfer agent and registrar for the common stock.

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Preferred Stock
Our board of directors is authorized to issue up to 5,000,000 shares of preferred stock in one or more series, with such rights, preferences and privileges as shall be determined by our board of directors. The rights, preferences and privileges of the holders of our common stock are subject to, and may be adversely affected by, the rights of the holders of shares of any series of our preferred stock that we may designateclassify and issue in the future.
Preferred Stock
We are authorized to issue “blank check” preferred stock, which may be issued in one or more series upon authorizationProvisions of our boardOur Certificate of directors. Our board of directors is authorized to fix the designation of the series, the number of authorized shares of the series, dividend rightsIncorporation and terms, conversion rights, voting rights, redemption rightsBy-laws and terms, liquidation preferences and any other rights, powers, preferences and limitations applicable to each series of preferred stock. The authorized shares of our preferred stock are available for issuance without further action by our stockholders, unless such action is required by applicable law or the rules of any stock exchange on which our securities may be listed. If the approval of our stockholders is not required for the issuance of shares of our preferred stock, our board may determine not to seek stockholder approval. The specific terms of any series of preferred stock offered pursuant to this prospectus will be described in the prospectus supplement relating to that series of preferred stock.
A series of our preferred stock could, depending on the terms of such series, impede the completion of a merger, tender offer or other takeover attempt. Our board of directors will make any determination to issue preferred shares based upon its judgment as to the best interests of our stockholders. Our directors, in so acting, could issue preferred stock having terms that could discourage an acquisition attempt through which an acquirer may be able to change the composition of our board of directors, including a tender offer or other transaction that some, or a majority, of our

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stockholders might believe to be in their best interests or in which stockholders might receive a premium for their stock over the then-current market price of the stock.
The preferred stock has the terms described below unless otherwise provided in the prospectus supplement relating to a particular series of preferred stock. You should read the prospectus supplement relating to the particular series of preferred stock being offered for specific terms, including:
the designation and stated value per share of the preferred stock and the number of shares offered;
the amount of liquidation preference per share;
the price at which the preferred stock will be issued;
the dividend rate, or method of calculation of dividends, the dates on which dividends will be payable, whether dividends will be cumulative or noncumulative and, if cumulative, the dates from which dividends will commence to accumulate;
any redemption or sinking fund provisions;
if other than the currency of the United States, the currency or currencies including composite currencies in which the preferred stock is denominated and/or in which payments will or may be payable;
a discussion of any material U.S. federal income tax considerations applicable to the preferred stock;
any conversion provisions;
whether we have elected to offer depositary shares as described under “Description of Depositary Shares”; and
any other rights, preferences, privileges, limitations and restrictions on the preferred stock.
The preferred stock will, when issued, be fully paid and non-assessable. Unless otherwise specified in the prospectus supplement, each series of preferred stock will rank equally as to dividends and liquidation rights in all respects with each other series of preferred stock. The rights of holders of shares of each series of preferred stock will be subordinate to those of our general creditors.
As described under “Description of Depositary Shares,” we may, at our option, with respect to any series of preferred stock, elect to offer fractional interests in shares of preferred stock, and provide for the issuance of depositary receipts representing depositary shares, each of which will represent a fractional interest in a share of the series of preferred stock. The fractional interest will be specified in the prospectus supplement relating to a particular series of preferred stock.
Rank. Unless otherwise specified in the prospectus supplement, the preferred stock will, with respect to dividend rights and rights upon our liquidation, dissolution or winding up of our affairs, rank:Delaware Law That May Have Anti-Takeover Effects
senior to our common stock and to all equity securities ranking junior to such preferred stock with respect to dividend rights or rights upon our liquidation, dissolution or winding up of our affairs;
on a parity with all equity securities issued by us, the terms of which specifically provide that such equity securities rank on a parity with the preferred stock with respect to dividend rights or rights upon our liquidation, dissolution or winding up of our affairs; and

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junior to all equity securities issued by us, the terms of which specifically provide that such equity securities rank senior to the preferred stock with respect to dividend rights or rights upon our liquidation, dissolution or winding up of our affairs.
The term “equity securities” does not include convertible debt securities.
Dividends. Holders of the preferred stock of each series will be entitled to receive, when, as and if declared by our board of directors, cash dividends at such rates and on such dates described in the prospectus supplement. Different series of preferred stock may be entitled to dividends at different rates or based on different methods of calculation. The dividend rate may be fixed or variable or both. Dividends will be payable to the holders of record as they appear on our stock books on record dates fixed by our board of directors, as specified in the applicable prospectus supplement.
Dividends on any series of preferred stock may be cumulative or noncumulative, as described in the applicable prospectus supplement. If our board of directors does not declare a dividend payable on a dividend payment date on any series of noncumulative preferred stock, then the holders of that noncumulative preferred stock will have no right to receive a dividend for that dividend payment date, and we will have no obligation to pay the dividend accrued for that period, whether or not dividends on that series are declared payable on any future dividend payment dates. Dividends on any series of cumulative preferred stock will accrue from the date we initially issue shares of such series or such other date specified in the applicable prospectus supplement.
No dividends may be declared or paid or funds set apart for the payment of any dividends on any parity securities unless full dividends have been paid or set apart for payment on the preferred stock. If full dividends are not paid, the preferred stock will share dividends pro rata with the parity securities.
No dividends may be declared or paid or funds set apart for the payment of dividends on any junior securities unless full dividends for all dividend periods terminating on or prior to the date of the declaration or payment will have been paid or declared and a sum sufficient for the payment set apart for payment on the preferred stock.
Liquidation Preference. Upon any voluntary or involuntary liquidation, dissolution or winding up of our affairs, then, before we make any distribution or payment to the holders of any common stock or any other class or series of our capital stock ranking junior to the preferred stock in the distribution of assets upon any liquidation, dissolution or winding up of our affairs, the holders of each series of preferred stock shall be entitled to receive out of assets legally available for distribution to stockholders, liquidating distributions in the amount of the liquidation preference per share set forth in the prospectus supplement, plus any accrued and unpaid dividends thereon. Such dividends will not include any accumulation in respect of unpaid noncumulative dividends for prior dividend periods. Unless otherwise specified in the prospectus supplement, after payment of the full amount of their liquidating distributions, the holders of preferred stock will have no right or claim to any of our remaining assets. Upon any such voluntary or involuntary liquidation, dissolution or winding up, if our available assets are insufficient to pay the amount of the liquidating distributions on all outstanding preferred stock and the corresponding amounts payable on all other classes or series of our capital stock ranking on parity with the preferred stock and all other such classes or series of shares of capital stock ranking on parity with the preferred stock in the distribution of assets, then the holders of the preferred stock and all other such classes or series of capital stock will share ratably in any such distribution of assets in proportion to the full liquidating distributions to which they would otherwise be entitled.
Upon any such liquidation, dissolution or winding up and if we have made liquidating distributions in full to all holders of preferred stock, we will distribute our remaining assets among the holders of any other classes or series of capital stock ranking junior to the preferred stock according to their respective rights and preferences and, in each case, according to their respective number of shares. For such purposes, our consolidation or merger with or into any other corporation, trust or entity, or the sale, lease or conveyance of all or substantially all of our property or assets will not be deemed to constitute a liquidation, dissolution or winding up of our affairs.
Redemption. If so provided in the applicable prospectus supplement, the preferred stock will be subject to mandatory redemption or redemption at our option, as a whole or in part, in each case upon the terms, at the times and at the redemption prices set forth in such prospectus supplement.

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The prospectus supplement relating to a series of preferred stock that is subject to mandatory redemption will specify the number of shares of preferred stock that shall be redeemed by us in each year commencing after a date to be specified, at a redemption price per share to be specified, together with an amount equal to all accrued and unpaid dividends thereon to the date of redemption. Unless the shares have a cumulative dividend, such accrued dividends will not include any accumulation in respect of unpaid dividends for prior dividend periods. We may pay the redemption price in cash or other property, as specified in the applicable prospectus supplement. If the redemption price for preferred stock of any series is payable only from the net proceeds of the issuance of shares of our capital stock, the terms of such preferred stock may provide that, if no such shares of our capital stock shall have been issued or to the extent the net proceeds from any issuance are insufficient to pay in full the aggregate redemption price then due, such preferred stock shall automatically and mandatorily be converted into the applicable shares of our capital stock pursuant to conversionCertain provisions specified in the applicable prospectus supplement. Notwithstanding the foregoing, we will not redeem any preferred stock of a series unless:
if that series of preferred stock has a cumulative dividend, we have declared and paid or contemporaneously declare and pay or set aside funds to pay full cumulative dividends on the preferred stock for all past dividend periods and the then current dividend period; or
if such series of preferred stock does not have a cumulative dividend, we have declared and paid or contemporaneously declare and pay or set aside funds to pay full dividends for the then current dividend period.
In addition, we will not acquire any preferred stock of a series unless:
if that series of preferred stock has a cumulative dividend, we have declared and paid or contemporaneously declare and pay or set aside funds to pay full cumulative dividends on all outstanding shares of such series of preferred stock for all past dividend periods and the then current dividend period; or
if that series of preferred stock does not have a cumulative dividend, we have declared and paid or contemporaneously declare and pay or set aside funds to pay full dividends on the preferred stock of such series for the then current dividend period.
However, at any time we may purchase or acquire preferred stock of that series (1) pursuant to a purchase or exchange offer made on the same terms to holders of all outstanding preferred stock of such series or (2) by conversion into or exchange for shares of our capital stock ranking junior to the preferred stock of such series as to dividends and upon liquidation.
If fewer than all of the outstanding shares of preferred stock of any series are to be redeemed, we will determine the number of shares that may be redeemed pro rata from the holders of record of such shares in proportion to the number of such shares held or for which redemption is requested by such holder or by any other equitable manner that we determine. Such determination will reflect adjustments to avoid redemption of fractional shares.
Unless otherwise specified in the prospectus supplement, we will mail notice of redemption at least 30 days but not more than 60 days before the redemption date to each holder of record of preferred stock to be redeemed at the address shown on our stock transfer books. Each notice shall state:
the redemption date;
the number of shares and series of preferred stock to be redeemed;
the redemption price;
the place or places where certificates for such preferred stock are to be surrendered for payment of the redemption price;

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that dividends on the shares to be redeemed will cease to accrue on such redemption date;
the date on which the holder’s conversion rights, if any, as to such shares shall terminate; and
the specific number of shares to be redeemed from each such holder if fewer than all the shares of any series are to be redeemed.
If notice of redemption has been given and we have set aside the funds necessary for such redemption in trust for the benefit of the holders of any shares called for redemption, then from and after the redemption date, dividends will cease to accrue on such shares, and all rights of the holders of such shares will terminate, except the right to receive the redemption price.
Voting Rights. Holders of preferred stock will not have any voting rights, except as required by law or as indicated in the applicable prospectus supplement.
Unless otherwise provided for under the terms of any series of preferred stock, no consent or vote of the holders of shares of preferred stock or any series thereof shall be required for any amendment to our certificate of incorporation that would increase the number of authorized shares of preferred stock or the number of authorized shares of any series thereof or decrease the number of authorized shares of preferred stock or the number of authorized shares of any series thereof (but not below the number of authorized shares of preferred stock or such series, as the case may be, then outstanding).
Conversion Rights. The terms and conditions, if any, upon which any series of preferred stock is convertible into our common stock will be set forth in the applicable prospectus supplement relating thereto. Such terms will include the number of shares of common stock into which the shares of preferred stock are convertible, the conversion price, rate or manner of calculation thereof, the conversion period, provisions as to whether conversion will be at our option or at the option of the holders of the preferred stock, the events requiring an adjustment of the conversion price and provisions affecting conversion in the event of the redemption.
Common Stock Warrants
As of March 13, 2018, we had outstanding:
warrants held by Silicon Valley Bank, or the SVB warrants, to purchase up to an aggregate of 55,000 shares of our common stock, at a weighted-average exercise price of $11.44 per share; and
warrants held by certain of our investors issued in connection with a publicly registered follow-on offering, or the November 2017 warrants, to purchase up to aggregate of 9,579,222 shares of our common stock, at a weighted-average exercise price of $0.80 per share.
These warrants provide for adjustments in the event of specified mergers, reorganizations, reclassifications, stock dividends, stock splits or other changes in our corporate structure. The SVB warrants are exercisable until November 24, 2024 and will be exercised automatically on a net issuance basis if not exercised prior to the expiration date and if the then-current fair market value of one share of our common stock is greater than the exercise price then in effect. The November 2017 warrants are exercisable until November 1, 2022 and as of March 13, 2018, 420,778 of the November 2017 warrants had been exercised.
Options to Purchase our Common Stock
As of March 13, 2018, options to purchase an aggregate of 2,795,796 shares of our common stock, at a weighted-average exercise price of $3.08 per share, were outstanding.
Delaware Anti-Takeover Law and Certain Charter and Bylaw provisions

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The following summary of certain provisions of Delaware law and of our certificate of incorporation and bylaws does not purport to be complete and is subject to and qualified in its entirety by reference to Delaware law and to our certificateby-laws may have the effect of incorporation and bylaws, copies of which are filed with the SEC as exhibits to the registration statement of which this prospectus forms a part.
Delaware Law. We are subject to Section 203 of the DGCL. Subject to certain exceptions, Section 203 prevents a publicly held Delaware corporation from engaging in a “business combination” with any “interested stockholder” for three years following the date that the person became an interested stockholder, unless either the interested stockholder attained such status with the approval of our board of directors, the business combination is approved by our board of directors and stockholders in a prescribed manner or the interested stockholder acquired at least 85% of our outstanding voting stock in the transaction in which it became an interested stockholder. A “business combination” includes, among other things, a merger or consolidation involving us and the “interested stockholder” and the sale of more than 10% of our assets. In general, an “interested stockholder” is any entity or person beneficially owning 15% or more of our outstanding voting stock and any entity or person affiliated with or controlling or controlled by such entity or person.
The restrictions in Section 203 do not apply to corporations that have elected, in the manner provided in Section 203, not to be subject to Section 203 of the DGCL or, with certain exceptions, which do not have a class of voting stock that is listed on a national securities exchange or held of record by more than 2,000 stockholders. Our certificate of incorporation and bylaws do not opt out of Section 203.
Section 203 could delay or prohibit mergers or other takeover or change in control attempts with respect to us and, accordingly, may discourage attempts to acquire us even though such a transaction may offer our stockholders the opportunity to sell their stock at a price above the prevailing market price.
Staggered Board; Removal of Directors. Our certificate of incorporation and our bylaws divide our board of directors into three classes with staggered three-year terms. In addition, our certificate of incorporation and our bylaws provide that directors may be removed only for cause and only by the affirmative vote of the holders of 75% of our shares of common stock present in person or by proxy and entitled to vote. Under our certificate of incorporation and bylaws, any vacancy on our board of directors, including a vacancy resulting from an enlargement of our board of directors, may be filled only by vote of a majority of our directors then in office. Furthermore, our certificate of incorporation provides that the authorized number of directors may be changed only by the resolution of our board of directors. The classification of our board of directors and the limitations on the ability of our stockholders to remove directors, change the authorized number of directors and fill vacancies could makemaking it more difficult for a third party to acquire, or discourageof discouraging a third party from seekingattempting to acquire, control of us. Such provisions could limit the price that certain investors might be willing to pay in the future for shares of our company.common stock and may limit the ability of stockholders to remove current management or directors or approve transactions that stockholders may deem to be in their best interest and, therefore, could adversely affect the price of our common stock.
No Cumulative Voting.   The Delaware General Corporation Law, or the DGCL, provides that stockholders are not entitled to the right to accumulate votes in the election of directors unless our certificate of incorporation provides otherwise. Our certificate of incorporation does not provide for cumulative voting.
Stockholder Action; Special MeetingBoard of Stockholders; Advance Notice Requirements for Stockholder Proposals and Director NominationsDirectors.   Our certificate of incorporation and our bylawsby-laws provide that any action required or permittedfor a board of directors divided as nearly equally as possible into three classes. Each class is elected to be taken by our stockholdersa term expiring at anthe annual meeting or special meeting of stockholders may only be taken if itheld in the third year following the year of such election. The number of directors comprising our board of directors is properly brought before such meeting and may not be taken by written action in lieu of a meeting. Our certificate of incorporation and our bylaws also provide that, except as otherwise required by law, special meetings of the stockholders can only be calledfixed from time to time by the chairmanboard of directors.
Removal of Directors by Stockholders.   Delaware law provides that members of our board of directors our chief executive officer or our board of directors. In addition, our bylaws establish an advance notice procedure for stockholder proposals to be brought before an annual meeting of stockholders, including proposed nominations of candidates for election to our board of directors. Stockholders at an annual meeting may only consider proposals or nominations specified in the notice of meeting or brought before the meeting by or at the direction of our board of directors, orbe removed for cause by a stockholdervote of record on the record date forholders of at least seventy-five percent (75%) of the meeting who isoutstanding shares entitled to vote aton the meeting and who has delivered timely written notice in proper form to our secretaryelection of the stockholder’s intention to bring such business before the meeting. These provisions could have the effectdirectors.
Board Vacancies Filled Only by Majority of delaying until the next stockholder meeting stockholder actions that are favoredDirectors Then in Office.   Vacancies and newly created seats on our board may be filled only by the holdersa vote of a majority of our outstanding voting securities. These provisions also could discourageboard of directors. Further, only our board of directors may determine the number of directors on our board. The inability of stockholders to determine the number of directors or to fill vacancies or newly created seats on the board makes it more difficult to change the composition of our board of directors.
Stockholder Nomination of Directors.   Our by-laws provide that a third party from makingstockholder must notify us in writing of any stockholder nomination of a tender offer for our common stock because evendirector not earlier than, the 120th day and not later than on the 90th day prior to the first anniversary of the preceding year’s annual meeting; provided, that if the third party acquired a majoritydate of our outstanding voting stock, it wouldthe annual meeting is advanced or delayed by more than 30 days from such anniversary date, notice by the stockholder to be abletimely must be so delivered not earlier than the 120th day prior to take action as a stockholder,the date of such as electing new directors or approving a merger, only at a duly called stockholdersannual meeting and not later than on the later of (x) the 90th day prior to the date of such meeting and (y) the 10th day following the day on which public announcement of the date of such annual meeting is first made by us.
No Action By Written Consent.   Our certificate of incorporation provides that our stockholders may not act by written consent.consent and may only act at duly called meetings of stockholders.

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Undesignated Preferred Stock.   As discussed above, our board of directors has the ability to issue preferred stock with voting or other rights or preferences that could impede the success of any attempt to change control of our company. These and other provisions may have the effect of deferring hostile takeovers or delaying changes in control or management of us.
Super-Majority Voting.The DGCLDelaware law provides generally that the affirmative vote of a majority of the shares entitled to vote on any matter is required to amend a corporation’s certificate of incorporation or bylaws unless a corporation’s certificate of incorporation or bylaws, as the case may be, requires a greater percentage. Our bylawsby-laws may be amended or repealed by a majority vote of our board of directors or the affirmative vote of the holders of at least 75% of the votes that all our stockholders would be entitled

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to cast in any annual election of directors. In addition, the affirmative vote of the holders of at least 75% of the votes that all our stockholders would be entitled to cast in any election of directors is required to amend or repeal or to adopt any provisions inconsistent with any of the provisions of our certificate of incorporation described above.
Registration Rights
Prior HoldersThese provisions of Series B Redeemable Convertible Preferred Stock. On February 9, 2010, we entered into an investors’ rights agreement, subsequently amended on April 23, 2012, which we refer to as the Investor Rights Agreement, with holders of our then-outstanding preferred stock. Under the Investor Rights Agreement, if holders of at least 25% of shares of common stock under the agreement request that we register their shares which represent an anticipated net aggregate offering price of at least $5 million, then we shall file a registration statement under the Securities Act covering such shares. In addition, if we propose to register for our own account any of our securities under the Securities Act, holders of at least 10% of shares of common stock under the agreement have the right to require us to use our best efforts to register all or a portion of their shares subject to the agreement and still held by them in such registration statement. If not otherwise exercised, the rights under the Investor Rights Agreement will expire on February 6, 2019, the fifth anniversary of the closing of our IPO.
Private Placement. On December 2, 2014, we entered into a registration rights agreement with certain holders of our common stock in connection with a private placement transaction. Under the registration rights agreement for the private placement, we were required to file a registration statement with the SEC, covering the resale of the 1,743,680 shares of common stock issued in the private placement and the 871,840 shares of common stock issuable upon exercise of the warrants issued in the private placement. A registration statement relating to such shares was filed on December 19, 2014 and declared effective by the SEC on December 31, 2014.
Shares Issued in our Acquisition of Viventia Bio Inc. In connection with our acquisition of Viventia, we entered into a registration rights agreement dated September 20, 2016, or the Registration Rights Agreement, with Clairmark Investments Ltd., or Clairmark, a former stockholder of Viventia and an affiliate of Leslie Dan, one of our directors, which acquired shares of our common stock in the acquisition. Under the Registration Rights Agreement, if Clairmark requests that we register at least 1,791,164 shares of our common stock which represent an anticipated net aggregate offering price of at least $5 million, then we shall file a registration statement under the Securities Act covering such shares. In addition, if we propose to register for our own account any of our securities under the Securities Act, Clairmark has the right to require us to use our best efforts to register all or a portion of the shares acquired in the acquisition and still held by it in such registration statement. If not otherwise exercised, the rights under the Registration Rights Agreement described below will expire on September 20, 2021.
Expenses.Pursuant to the Investor Rights Agreement and the Registration Rights Agreement, we are required to pay all registration expenses, including the fees and expenses of one counsel to represent such holders of our common stock, other than any underwriting discounts, selling commissions and fees and expenses of such holder's own counsel related to any demand or incidental registration. We are not required to pay registration expenses if the registration request under the Investor Rights Agreement or the Registration Rights Agreement is withdrawn at the request of such holders, unless the withdrawal is due to discovery of a materially adverse change in our business after the initiation of such registration request.
The Investor Rights Agreement and the Registration Rights Agreement contain customary cross-indemnification provisions, pursuant to which we are obligated to indemnify such holders in the event of material misstatements or omissions in the registration statement attributable to us or any violation or alleged violation whether by action or inaction by us under the Securities Act, the Exchange Act, any state securities or Blue SkyDelaware law, or any rule or regulation promulgated under the Securities Act, the Exchange Act or any state securities or Blue Sky law in connection with such

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registration statement or the qualification or compliance of the offering, and such holders are obligated to indemnify us for material misstatements or omissions in the registration statement attributable to it.
All applicable registration rights with respect to the registration statement of which this prospectus forms a part have been waived.
Transfer Agent and Registrar
The transfer agent and registrar for our common stock is Computershare Trust Company, Inc.
Stock Market Listing
Our common stock is listed for trading on the Nasdaq Global Market under the symbol “EBIO.”

DESCRIPTION OF OUR DEPOSITARY SHARES
General
We may, at our option, elect to offer fractional shares of preferred stock, which we call depositary shares, rather than full shares of preferred stock. If we do, we will issue to the public receipts, called depositary receipts, for depositary shares, each of which will represent a fraction, to be described in the applicable prospectus supplement, of a share of a particular series of preferred stock. Unless otherwise provided in the prospectus supplement, each owner of a depositary share will be entitled, in proportion to the applicable fractional interest in a share of preferred stock represented by the depositary share, to all the rights and preferences of the preferred stock represented by the depositary share. Those rights include dividend, voting, redemption, conversion and liquidation rights.
The shares of preferred stock underlying the depositary shares will be deposited with a bank or trust company selected by us to act as depositary under a deposit agreement between us, the depositary and the holders of the depositary receipts. The depositary will be the transfer agent, registrar and dividend disbursing agent for the depositary shares.
The depositary shares will be evidenced by depositary receipts issued pursuant to the deposit agreement. Holders of depositary receipts agree to be bound by the deposit agreement, which requires holders to take certain actions such as filing proof of residence and paying certain charges.
The summary of terms of the depositary shares contained in this prospectus is not a complete description of the terms of the depository shares. You should refer to the form of the deposit agreement, our certificate of incorporation and by-laws may have the certificateeffect of designationdeterring hostile takeovers or delaying changes in our control or in our management. These provisions are intended to enhance the likelihood of continued stability in the composition of our board of directors and in the policies they implement, and to discourage certain types of transactions that may involve an actual or threatened change of our control. These provisions are designed to reduce our vulnerability to an unsolicited acquisition proposal. The provisions also are intended to discourage certain tactics that may be used in proxy fights. However, such provisions could have the effect of discouraging others from making tender offers for our shares and, as a consequence, they also may inhibit fluctuations in the applicable seriesmarket price of preferredour shares that could result from actual or rumored takeover attempts.
Delaware Business Combination Statute.   We are subject to Section 203 of the DGCL, or Section 203, which prohibits a Delaware corporation from engaging in business combinations with an interested stockholder. An interested stockholder is generally defined as an entity or person beneficially owning 15% or more of the outstanding voting stock of the corporation or any entity or person affiliated with or controlling or controlled by such entity or person, or interested stockholder. Section 203 provides that an interested stockholder may not engage in business combinations with the corporation for a period of three years after the date that such stockholder became an interested stockholder, with the following exceptions:
•
before such date, the board of directors of the corporation approved either the business combination or the transaction that resulted in the stockholder becoming an interested stockholder;
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•
upon completion of the transaction that resulted in the stockholder becoming an interested stockholder, the interested stockholder owned at least 85% of the voting stock of the corporation outstanding at the time the transaction began, excluding for purposes of determining the voting stock outstanding (but not the outstanding voting stock owned by the interested stockholder) those shares owned (i) by persons who are directors and also officers and (ii) employee stock plans in which employee participants do not have the right to determine confidentially whether shares held subject to the plan will be tendered in a tender or exchange offer; or
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•
on or after such date, the business combination is approved by the board of directors and authorized at an annual or special meeting of the stockholders, and not by written consent, by the affirmative vote of at least 66 2/3% of the outstanding voting stock that are,is not owned by the interested stockholder.
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In general, Section 203 defines business combinations to include the following:
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any merger or will be, filedconsolidation involving the corporation and the interested stockholder;
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•
any sale, lease, transfer, pledge or other disposition of 10% or more of the assets of the corporation to or with the SEC.interested stockholder;
Dividends and Other Distributions​
The depositary will distribute all cash dividends•
subject to certain exceptions, any transaction that results in the issuance or other cash distributions, iftransfer by the corporation of any received in respectstock of the preferred stock underlying the depositary sharescorporation to the record holdersinterested stockholder;
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•
any transaction involving the corporation that has the effect of depositary shares in proportion toincreasing the numbers of depositary shares owned by those holders on the relevant record date. The relevant record date for depositary shares will be the same date as the record date for the underlying preferred stock.
If there is a distribution other than in cash, the depositary will distribute property (including securities) received by it to the record holders of depositary shares, unless the depositary determines that it is not feasible to make the distribution. If this occurs, the depositary may, with our approval, adopt another method for the distribution, including selling the property and distributing the net proceeds from the sale to the holders.
Liquidation Preference

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If a series of preferred stock underlying the depositary shares has a liquidation preference, in the event of the voluntary or involuntary liquidation, dissolution or winding up of us, holders of depositary shares will be entitled to receive the fraction of the liquidation preference accorded eachproportionate share of the applicablestock or any class or series of preferred stock, as set forth in the applicable prospectus supplement.corporation beneficially owned by the interested stockholder; or
Withdrawal of Stock​
Unless •
the related depositary shares have been previously called for redemption, upon surrenderreceipt by the interested stockholder of the depositary receipts atbenefit of any loss, advances, guarantees, pledges or other financial benefits by or through the office of the depositary, the holder of the depositary shares will be entitled to delivery, at the office of the depositary tocorporation.
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TABLE OF CONTENTS​

PLAN OF DISTRIBUTION
The selling stockholders, which as used herein includes donees, pledgees, transferees or upon his or her order, of the number of wholeother successors-in-interest selling shares of common stock or interests in shares of common stock received after the preferred stock and any moneydate of this prospectus from a selling stockholder as a gift, pledge, partnership distribution or other property represented by the depositary shares. If the depositary receipts delivered by the holder evidence a number of depositary shares in excess of the number of depositary shares representing the number of whole shares of preferred stock to be withdrawn, the depositary will deliver to the holder at the same time a new depositary receipt evidencing the excess number of depositary shares. In no event will the depositary deliver fractional shares of preferred stock upon surrender of depositary receipts. Holders of preferred stock thus withdrawn may not thereafter deposit those shares under the deposit agreement or receive depositary receipts evidencing depositary shares therefor.
Redemption of Depositary Shares
Whenever we redeem shares of preferred stock held by the depositary, the depositary will redeem as of the same redemption date the number of depositary shares representing shares of the preferred stock so redeemed, so long as we have paid in full to the depositary the redemption price of the preferred stock to be redeemed plus an amount equal to any accumulated and unpaid dividends on the preferred stock to the date fixed for redemption. The redemption price per depositary share will be equal to the redemption price and any other amounts per share payable on the preferred stock multiplied by the fraction of a share of preferred stock represented by one depositary share. If less than all the depositary shares are to be redeemed, the depositary shares to be redeemed will be selected by lot or pro rata or by any other equitable method as may be determined by the depositary.
After the date fixed for redemption, depositary shares called for redemption will no longer be deemed to be outstanding and all rights of the holders of depositary shares will cease, except the right to receive the monies payable upon redemption and any money or other property to which the holders of the depositary shares were entitled upon redemption upon surrender to the depositary of the depositary receipts evidencing the depositary shares.
Voting the Preferred Stock
Upon receipt of notice of any meeting at which the holders of the preferred stock are entitled to vote, the depositary will mail the information contained in the notice of meeting to the record holders of the depositary receipts relating to that preferred stock. The record date for the depositary receipts relating to the preferred stock will be the same date as the record date for the preferred stock. Each record holder of the depositary shares on the record date will be entitled to instruct the depositary as to the exercise of the voting rights pertaining to the number of shares of preferred stock represented by that holder’s depositary shares. The depositary will endeavor, insofar as practicable, to vote the number of shares of preferred stock represented by the depositary shares in accordance with those instructions, and we will agree to take all action that may be deemed necessary by the depositary in order to enable the depositary to do so. The depositary will not vote any shares of preferred stock except to the extent it receives specific instructions from the holders of depositary shares representing that number of shares of preferred stock.
Charges of Depositary
We will pay all transfer, and other taxes and governmental charges arising solely from the existence of the depositary arrangements. We will pay charges of the depositary in connection with the initial deposit of the preferred stock and any redemption of the preferred stock. Holders of depositary receipts will pay transfer, income and other taxes and governmental charges and such other charges (including those in connection with the receipt and distribution of dividends, the sale or exercise of rights, the withdrawal of the preferred stock and the transferring, splitting or grouping of depositary receipts) as are expressly provided in the deposit agreement to be for their accounts. If these charges have

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not been paid by the holders of depositary receipts, the depositary may refuse to transfer depositary shares, withhold dividends and distributions and sell the depositary shares evidenced by the depositary receipt.
Amendment and Termination of the Deposit Agreement
The form of depositary receipt evidencing the depositary shares and any provision of the deposit agreement may be amended by agreement between us and the depositary. However, any amendment that materially and adversely alters the rights of the holders of depositary shares, other than fee changes, will not be effective unless the amendment has been approved by the holders of a majority of the outstanding depositary shares. The deposit agreement may be terminated by the depositary or us only if:
all outstanding depositary shares have been redeemed; or
there has been a final distribution of the preferred stock in connection with our dissolution and such distribution has been made to all the holders of depositary shares.
Resignation and Removal of Depositary
The depositary may resign at any time by delivering to us notice of its election to do so, and we may remove the depositary at any time. Any resignation or removal of the depositary will take effect upon our appointment of a successor depositary and its acceptance of such appointment. The successor depositary must be appointed within 60 days after delivery of the notice of resignation or removal and must be a bank or trust company having its principal office in the United States and having the requisite combined capital and surplus as set forth in the applicable agreement.
Notices
The depositary will forward to holders of depositary receipts all notices, reports and other communications, including proxy solicitation materials received from us, that are delivered to the depositary and that we are required to furnish to the holders of the preferred stock. In addition, the depositary will make available for inspection by holders of depositary receipts at the principal office of the depositary, and at such other places as it may, from time to time, deem advisable, any reports and communications we deliver to the depositary as the holder of preferred stock.
Limitation of Liability
Neither we nor the depositary will be liable if either wesell, transfer or it is prevented or delayed by law or any circumstance beyond its control in performing its obligations. Our obligations and those of the depositary will be limited to performance in good faith of our and their duties thereunder. We and the depositary will not be obligated to prosecute or defend any legal proceeding in respectotherwise dispose of any depositary shares or preferred stock unless satisfactory indemnity is furnished. We and the depositary may rely upon written adviceall of counsel or accountants, on information provided by persons presenting preferred stock for deposit, holders of depositary receipts or other persons believed to be competent to give such information and on documents believed to be genuine and to have been signed or presented by the proper party or parties.

DESCRIPTION OF PURCHASE CONTRACTS AND PURCHASE UNITS
We may issue purchase contracts, including contracts obligating holders to purchase from or sell to us, and obligating us to sell to or purchase from the holders, a specified number of shares of our common stock, preferred stock or depositary shares at a future date or dates, which we refer to in this prospectus as purchase contracts. The price per share of common stock, preferred stock or depositary shares and the number of shares of each may be fixed at the time the purchase contracts are issued or may be determined by reference to a specific formula set forth in the purchase contracts. The purchase contracts may be issued separately or as part of units, often known as purchase units, consisting of one or more purchase contracts and beneficial interests in debt securities or any other securities described in the

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applicable prospectus supplement or any combination of the foregoing, securing the holders’ obligations to purchase the common stock, preferred stock or depositary shares under the purchase contracts.
The purchase contracts may require us to make periodic payments to the holders of the purchase units or vice versa, and these payments may be unsecured or prefunded on some basis. The purchase contracts may require holders to secure their obligations under those contracts in a specified manner, including pledging their interest in another purchase contract.
The applicable prospectus supplement will describe the terms of the purchase contracts and purchase units, including, if applicable, collateral or depositary arrangements.

DESCRIPTION OF OUR WARRANTS
We may issue warrants to purchase common stock, preferred stock, depositary shares or debt securities. We may offer warrants separately or together with one or more additional warrants, common stock, preferred stock, depositary shares or debt securities, or any combination of those securities in the form of units, as described in the applicable prospectus supplement. If we issue warrants as part of a unit, the accompanying prospectus supplement will specify whether those warrants may be separated from the other securities in the unit prior to the expiration date of the warrants. The applicable prospectus supplement will also describe the following terms of any warrants:
the specific designation and aggregate number of, and the offering price at which we will issue, the warrants;
the currency or currency units in which the offering price, if any, and the exercise price are payable;
the date on which the right to exercise the warrants will begin and the date on which that right will expire or, if you may not continuously exercise the warrants throughout that period, the specific date or dates on which you may exercise the warrants;
whether the warrants are to be sold separately or with other securities as parts of units;
whether the warrants will be issued in definitive or global form or in any combination of these forms, although, in any case, the form of a warrant included in a unit will correspond to the form of the unit and of any security included in that unit;
any applicable material U.S. federal income tax consequences;
the identity of the warrant agent for the warrants and of any other depositaries, execution or paying agents, transfer agents, registrars or other agents;
the proposed listing, if any, of the warrants or any securities purchasable upon exercise of the warrants on any securities exchange;
the designation and terms of any equity securities purchasable upon exercise of the warrants;
the designation, aggregate principal amount, currency and terms of any debt securities that may be purchased upon exercise of the warrants;
if applicable, the designation and terms of the preferred stock or depositary shares with which the warrants are issued and the number of warrants issued with each security;
if applicable, the date from and after which any warrants issued as part of a unit and the related debt securities, preferred stock, depositary shares or common stock will be separately transferable;

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the number of shares of common stock preferredor interests in shares of common stock on any stock exchange, market or depositarytrading facility on which the shares purchasable upon exerciseare traded or in private transactions. These dispositions may be at fixed prices, at prevailing market prices at the time of a warrant andsale, at prices related to the prevailing market price, at which those sharesvarying prices determined at the time of sale, or at negotiated prices.
The selling stockholders may be purchased;
if applicable, the minimum or maximum amount of the warrants that may be exercised atuse any one time;
information with respect to book-entry procedures, if any;
the anti-dilution provisions of, and other provisions for changes to or adjustment in the exercise price of, the warrants, if any;
any redemption or call provisions; and
any additional terms of the warrants, including terms, procedures and limitations relating to the exchange or exercise of the warrants.;
Description of Outstanding Warrants
As of March 13, 2018, there were 9,634,222 warrants to purchase shares of our common stock outstanding. See “Description of Our Capital Stock - Common Stock Warrants.”

FORMS OF SECURITIES
Each debt security, depositary share, purchase contract, purchase unit and warrant may be represented either by a certificate issued in definitive form to a particular investor or by one or more global securities representing the entire issuance of securities. Unless the applicable prospectus supplement provides otherwise, certificated securities in definitive form and global securities will be issued in registered form. Definitive securities name you or your nominee as the owner of the security,following methods when disposing of shares or interests therein:
•
ordinary brokerage transactions and in order to transfer or exchange these securities or to receive payments other than interest or other interim payments, you or your nominee must physically deliver the securities to the trustee, registrar, paying agent or other agent, as applicable. Global securities name a depositary or its nominee as the owner of the debt securities, depositary shares, purchase contracts, purchase units or warrants represented by these global securities. The depositary maintains a computerized system that will reflect each investor’s beneficial ownership of the securities through an account maintained by the investor with its broker/dealer, bank, trust company or other representative, as we explain more fully below.
Global Securities
We may issue the debt securities, depositary shares, purchase contracts, purchase units and warrants in the form of one or more fully registered global securities that will be deposited with a depositary or its nominee identified in the applicable prospectus supplement and registered in the name of that depositary or nominee. In those cases, one or more global securities will be issued in a denomination or aggregate denominations equal to the portion of the aggregate principal or face amount of the securities to be represented by global securities. Unless and until it is exchanged in whole for securities in definitive registered form, a global security may not be transferred except as a whole by and among the depositary for the global security, the nominees of the depositary or any successors of the depositary or those nominees.
If not described below, any specific terms of the depositary arrangement with respect to any securities to be represented by a global security will be described in the prospectus supplement relating to those securities. We anticipate that the following provisions will apply to all depositary arrangements.
Ownership of beneficial interests in a global security will be limited to persons, called participants, that have accounts with the depositary or persons that may hold interests through participants. Upon the issuance of a global security, the depositary will credit, on its book-entry registration and transfer system, the participants’ accounts with the respective principal or face amounts of the securities beneficially owned by the participants. Any dealers, underwriters or agents

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participating in the distribution of the securities will designate the accounts to be credited. Ownership of beneficial interests in a global security will be shown on, and the transfer of ownership interests will be effected only through, records maintained by the depositary, with respect to interests of participants, and on the records of participants, with respect to interests of persons holding through participants. The laws of some states may require that some purchasers of securities take physical delivery of these securities in definitive form. These laws may impair your ability to own, transfer or pledge beneficial interests in global securities.
So long as the depositary, or its nominee, is the registered owner of a global security, that depositary or its nominee, as the case may be, will be considered the sole owner or holder of the securities represented by the global security for all purposes under the applicable indenture, deposit agreement, purchase contract, warrant agreement or purchase unit agreement. Except as described below, owners of beneficial interests in a global security will not be entitled to have the securities represented by the global security registered in their names, will not receive or be entitled to receive physical delivery of the securities in definitive form and will not be considered the owners or holders of the securities under the applicable indenture, deposit agreement, purchase contract, purchase unit agreement or warrant agreement. Accordingly, each person owning a beneficial interest in a global security must rely on the procedures of the depositary for that global security and, if that person is not a participant, on the procedures of the participant through which the person owns its interest, to exercise any rights of a holder under the applicable indenture, deposit agreement, purchase contract, purchase unit agreement or warrant agreement. We understand that under existing industry practices, if we request any action of holders or if an owner of a beneficial interest in a global security desires to give or take any action that a holder is entitled to give or take under the applicable indenture, deposit agreement, purchase contract, purchase unit agreement or warrant agreement, the depositary for the global security would authorize the participants holding the relevant beneficial interests to give or take that action, and the participants would authorize beneficial owners owning through them to give or take that action or would otherwise act upon the instructions of beneficial owners holding through them.
Principal, premium, if any, and interest payments on debt securities, and any payments to holders with respect to depositary shares, warrants, purchase agreements or purchase units, represented by a global security registered in the name of a depositary or its nominee will be made to the depositary or its nominee, as the case may be, as the registered owner of the global security. None of us, or any trustee, warrant agent, unit agent or other agent of ours, or any agent of any trustee, warrant agent or unit agent will have any responsibility or liability for any aspect of the records relating to payments made on account of beneficial ownership interests in the global security or for maintaining, supervising or reviewing any records relating to those beneficial ownership interests.
We expect that the depositary for any of the securities represented by a global security, upon receipt of any payment to holders of principal, premium, interest or other distribution of underlying securities or other property on that registered global security, will immediately credit participants’ accounts in amounts proportionate to their respective beneficial interests in that global security as shown on the records of the depositary. We also expect that payments by participants to owners of beneficial interests in a global security held through participants will be governed by standing customer instructions and customary practices, as is now the case with the securities held for the accounts of customers or registered in “street name,” and will be the responsibility of those participants.
If the depositary for any of the securities represented by a global security is at any time unwilling or unable to continue as depositary or ceases to be a clearing agency registered under the Exchange Act, and a successor depositary registered as a clearing agency under the Exchange Act is not appointed by us within 90 days, we will issue securities in definitive form in exchange for the global security that had been held by the depositary. Any securities issued in definitive form in exchange for a global security will be registered in the name or names that the depositary gives to the relevant trustee, warrant agent, unit agent or other relevant agent of ours or theirs. It is expected that the depositary’s instructions will be based upon directions received by the depositary from participants with respect to ownership of beneficial interests in the global security that had been held by the depositary.

PLAN OF DISTRIBUTION
We may sell the securities being offered by this prospectus separately or together:

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directly to purchasers;
through agents;
to or through underwriters;
through dealers;
through a block tradetransactions in which the broker or dealer engaged to handlebroker-dealer solicits purchasers;
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•
block trades in which the block tradebroker-dealer will attempt to sell the securitiesshares as agent, but may position and resell a portion of the block as principal to facilitate the transaction; or
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•
purchases by a broker-dealer as principal and resale by the broker-dealer for its account;
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an exchange distribution in accordance with the rules of the applicable exchange;
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privately negotiated transactions;
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short sales;
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•
through the writing or settlement of options or other hedging transactions, whether through an options exchange or otherwise;
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•
broker-dealers may agree with a selling stockholder to sell a specified number of such shares at a stipulated price per share;
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•
a combination of any of thesesuch methods of sale.sale; and
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In addition, we•
any other method permitted by applicable law.
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The selling stockholders may, issue the securities being offered by this prospectus as a dividend or distribution or in a subscription rights offering to our existing security holders. This prospectus may be used in connection with any offering of our securities through any of these methods or other methods described in the applicable prospectus supplement or free writing prospectus.
We may directly solicit offers to purchase securities, or agents may be designated to solicit such offers. We will, in the prospectus supplement relating to such offering, name any agent that could be viewed as an underwriter under the Securities Act, and describe any commissions that we must pay. Any such agent will be acting on a best efforts basis for the period of its appointment or, if indicated in the applicable prospectus supplement, on a firm commitment basis.
We may effect the distribution of the securities from time to time, pledge or grant a security interest in onesome or more transactions:
at a fixed price,all of the shares of common stock owned by them and, if they default in the performance of their secured obligations, the pledgees or prices, whichsecured parties may be changedoffer and sell the shares of common stock, from time to time;
at market prices prevailing at the time, of sale;
at prices related to such prevailing market prices; or
at negotiated prices.
For example, we may engage in at-the-market offerings into an existing trading market in accordance with Rule 415(a)(4) under the Securities Act. We may also sell securities through a rights offering, forward contracts or similar arrangements. In any distribution of subscription rights to shareholders, if all of the underlying securities are not subscribed for, we may then sell the unsubscribed securities directly to third parties or may engage the services of one or more underwriters, dealers or agents, including standby underwriters, to sell the unsubscribed securities to third parties.
Except as described in a prospectus supplement or a free writing prospectus, the securities issued and sold under this prospectus, or under an amendment to this prospectus under Rule 424(b)(3) or other applicable provision of the Securities Act, amending the list of selling stockholders to include the pledgee, transferee or other successors in interest as selling stockholders under this prospectus. The selling stockholders also may transfer the shares of common stock in other circumstances, in which case the transferees, pledgees or other successors in interest will have no established trading market, other thanbe the selling beneficial owners for purposes of this prospectus.
In connection with the sale of our common stock or interests therein, the selling stockholders may enter into hedging transactions with broker-dealers or other financial institutions, which is listed onmay in turn engage in short sales of the Nasdaq Global Market. Except as describedcommon stock in a prospectus supplement or a free writing prospectus, anythe course of hedging the positions they assume. The selling stockholders may also sell shares of our common stock soldshort and deliver these securities to close out their short positions, or loan or pledge the common stock to broker-dealers that in turn may sell these securities. The selling stockholders may also enter into option or other transactions with broker-dealers or other financial institutions or the creation of one or more derivative securities which require the delivery to such broker-dealer or other financial institution of shares offered by this prospectus, which shares such broker-dealer or other financial institution may resell pursuant to this prospectus (as supplemented or amended to reflect such transaction).
The aggregate proceeds to the selling stockholders from the sale of the common stock offered by them will be eligible for listing and trading on the Nasdaq Global Market, subject to official notice of issuance. Any underwriters to whom securities are sold by us for public offering and sale may make a market in the securities, but the underwriters will not be obligated to do so and may discontinue any market making at any time without notice. The securities, other than our common stock, may or may not be listed on a national securities exchange or other trading market.
We will set forth in a prospectus supplement or free writing prospectus:
the terms of any underwriting or other agreement that we reach relating to sales under this prospectus;

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the method of distribution of the securities;
the names of any agents, underwriters or dealers, including any managing underwriters, used in the offering of securities;
 the terms of any direct sales, including the terms of any bidding or auction process, or the terms of any other transactions;
the compensation payable to agents, underwriters and dealers, which may be in the form of discounts, concessions or commissions;
any activities that may be undertaken by agents, underwriters and dealers to stabilize, maintain or otherwise affect thepurchase price of the securities;common stock less discounts or commissions, if any. Each of the selling stockholders reserves the right to accept and, together with their agents from time to time, to reject, in whole or in part, any proposed purchase of common stock to be made directly or through agents. We will not receive any of the proceeds from this offering.
 any indemnification

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TABLE OF CONTENTS

The selling stockholders also may resell all or a portion of the shares in open market transactions in reliance upon Rule 144 under the Securities Act, provided that they meet the criteria and contribution obligations owingconform to agents, underwritersthe requirements of that rule.
The selling stockholders and dealers.
If any underwriters, broker-dealers or agents are utilizedthat participate in the sale of the securities in respectcommon stock or interests therein may be “underwriters” within the meaning of which this prospectus is delivered, weSection 2(a)(11) of the Securities Act. Any discounts, commissions, concessions or profit they earn on any resale of the shares may be underwriting discounts and commissions under the Securities Act. Selling stockholders who are “underwriters” within the meaning of Section 2(a)(11) of the Securities Act will enter into an underwriting agreement or other agreement with them at the time of salebe subject to them, and we will set forth in the prospectus supplement relatingdelivery requirements of the Securities Act.
To the extent required, the shares of our common stock to such offeringbe sold, the names of the underwritersselling stockholders, the respective purchase prices and public offering prices, the names of any agent, dealer or agentsunderwriter, and any applicable commissions or discounts with respect to a particular offer will be set forth in an accompanying prospectus supplement or, if appropriate, a post-effective amendment to the termsregistration statement that includes this prospectus.
In order to comply with the securities laws of some states, if applicable, the common stock may be sold in these jurisdictions only through registered or licensed brokers or dealers. In addition, in some states the common stock may not be sold unless it has been registered or qualified for sale or an exemption from registration or qualification requirements is available and is complied with.
We have advised the selling stockholders that the anti-manipulation rules of Regulation M under the Exchange Act may apply to sales of shares in the market and to the activities of the related agreement with them.
Ifselling stockholders and their affiliates. In addition, to the extent applicable, we sell directly to institutional investors or others, theywill make copies of this prospectus (as it may be deemedsupplemented or amended from time to be underwriters withintime) available to the meaningselling stockholders for the purpose of satisfying the prospectus delivery requirements of the Securities Act with respect toAct. The selling stockholders may indemnify any resale of the securities. Unless otherwise indicatedbroker-dealer that participates in a prospectus supplement or free writing prospectus, if we sell through an agent, such agent will be acting on a best efforts basis for the period of its appointment. Any agent may be deemed to be an “underwriter” of the securities as that term is defined in the Securities Act.  If a dealer is used intransactions involving the sale of the securities, we or an underwriter will sell securities to the dealer, as principal. The dealer may resell the securities to the public at varying prices to be determined by the dealer at the time of resale.
If we offer securities in a subscription rights offering to our existing security holders, we may enter into a standby underwriting agreement with dealers, acting as standby underwriters. We may pay the standby underwriters a commitment fee for the securities they commit to purchase on a standby basis. If we do not enter into a standby underwriting arrangement, we may retain a dealer-manager to manage a subscription rights offering for us.
Remarketing firms, agents, underwriters, dealers and other persons may be entitled under agreements which they may enter into with us to indemnification by usshares against certain civilliabilities, including liabilities arising under the Securities Act.
We have agreed to indemnify the selling stockholders against liabilities, including liabilities under the Securities Act and may be customersstate securities laws, relating to the registration of engage in transactions with or perform services for us in the ordinary course of business.shares offered by this prospectus.
We may authorize agents, underwritershave agreed with the selling stockholders to use reasonable best efforts to cause the registration statement of which this prospectus constitutes a part to become effective and dealers to solicit offers by certain institutional investorsmaintain such effectiveness continuously for a period up to purchase offered securities under contracts providing for payment and delivery on a futurethe earlier of (i) three years from the date specified in a prospectus supplement or free writing prospectus. The prospectus supplement or free writing prospectus will also describe the public offering price for the securities and the commission payable for solicitation of these delayed delivery contracts. Delayed delivery contracts will contain definite fixed price and quantity terms. The obligations of a purchase under these delayed delivery contracts will be subject to only two conditions:
that the institution’s purchase of the securities atRegistration Rights Agreement and (ii) the time of delivery ofdate that all Registrable Subscription Securities covered by the securities is not prohibited under the law of any jurisdictionregistration statement on Form S-3 have been sold or can be sold without restriction pursuant to which the institution is subject; and
if the securities are also being sold to underwriters acting as principals for their own account, the underwriters shall have purchased such securities not sold for delayed delivery. The underwriters and other persons acting as our agents will not have any responsibility in respect of the validitySEC Rule 144, or performance of delayed delivery contracts.
To the extent permitted by and in accordance with Regulation Manother similar exemption under the Securities Exchange Act and without the requirement to be in compliance with subsection (c)(1) of 1934, as amended, or the Exchange Act, in connection with an offering an underwriter may engage in over-allotments, stabilizingSEC Rule 144 (or any successor thereto).

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transactions, short covering transactions and penalty bids. Over-allotments involve sales in excess of the offering size, which creates a short position. Stabilizing transactions permit bids to purchase the underlying security so long as the stabilizing bids do not exceed a specified maximum. Short covering transactions involve purchases of the securities in the open market after the distribution is completed to cover short positions. Penalty bids permit the underwriters to reclaim a selling concession from a dealer when the securities originally sold by the dealer are purchased in a covering transaction to cover short positions. Those activities may cause the price of the securities to be higher than it would be otherwise. If commenced, the underwriters may discontinue any of the activities at any time.
To the extent permitted by and in accordance with Regulation M under the Exchange Act, any underwriters who are qualified market makers on Nasdaq may engage in passive market making transactions in the securities on Nasdaq during the business day prior to the pricing of an offering, before the commencement of offers or sales of the securities. Passive market makers must comply with applicable volume and price limitations and must be identified as passive market makers. In general, a passive market maker must display its bid at a price not in excess of the highest independent bid for such security; if all independent bids are lowered below the passive market maker’s bid, however, the passive market maker’s bid must then be lowered when certain purchase limits are exceeded.
The specific terms of any lock-up provisions in respect of any given offering will be described in the applicable prospectus supplement or free writing prospectus.
Under Rule 15c6-1 of the Exchange Act, trades in the secondary market generally are required to settle in two business days, unless the parties to any such trade expressly agree otherwise. The applicable prospectus supplement may provide that the original issue date for your securities may be more than two scheduled business days after the trade date for your securities. Accordingly, in such a case, if you wish to trade securities on any date prior to the second business day before the original issue date for your securities, you will be required, by virtue of the fact that your securities initially are expected to settle more than two scheduled business days after the trade date for your securities, to make alternative settlement arrangements to prevent a failed settlement.
In compliance with the guidelines of the Financial Industry Regulatory Authority, or FINRA, the aggregate maximum discount, commission or agency fees or other items constituting underwriting compensation to be received by any FINRA member or independent broker-dealer will not exceed 8% of the proceeds from any offering pursuant to this prospectus and any applicable prospectus supplement.
The underwriters, dealers and agents may engage in transactions with us, or perform services for us, in the ordinary course of business for which they receive compensation.
No securities may be sold under this prospectus without delivery, in paper format or in electronic format, or both, of the applicable prospectus supplement or free writing prospectus describing the method and terms of the offering.

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LEGAL MATTERS
The validity of the issuanceshares of the securitiesour common stock offered hereby will beby this prospectus has been passed upon for us by Hogan Lovells USWilmer Cutler Pickering Hale and Dorr LLP. As appropriate, legal counsel representing the underwriters, dealers or agents will be named in the accompanying prospectus supplement and may opine to certain legal matters.

EXPERTS
EXPERTS
Ernst & Young LLP, independent registered public accounting firm, has audited ourthe consolidated financial statements of Carisma Therapeutics Inc. (formerly Sesen Bio, Inc.) included in our Annual Report on Form 10–K10-K for the year ended December 31, 2016,2022, as set forth in their report, which contains an explanatory paragraph describing conditions that raise substantial doubt about the Company's ability to continue as a going concern as described in Note 1 to the consolidated financial statements, included therein, and which areis incorporated by reference in this prospectus and elsewhere in the registration statement. OurSuch financial statements

29


are incorporated by reference in reliance on Ernst & Young LLP'sLLP’s report, given on their authority as experts in accounting and auditing.
The consolidated financial statements of Viventia included in Eleven Biotherapeutics,Carisma Therapeutics Inc.'s Current Report on Form 8-K/A dated as of December 6, 2016, (which contains an explanatory paragraph describing conditions that raise substantial doubt about Viventia's ability to continue as a going concern as described in Note 1 to31, 2022 and 2021, and for the consolidated financial statements, included therein) andyears then ended, have been incorporated by reference as Exhibits 99.1herein and 99.2 toin the registration statement of which this prospectus forms a part, have been incorporated in reliance onupon the report of PricewaterhouseCoopersKPMG LLP, independent auditors, given onregistered public accounting firm, incorporated by reference herein, and upon the authority of said firm as experts in auditingaccounting and accounting.auditing.

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WHERE YOU CAN FIND MORE INFORMATION
We file annual, quarterly and current reports, proxy statements and other information with the SEC. Our SEC filings are available to the public over the Internet at the SEC’s website at www.sec.gov. Copies of certain information filed by us with the SEC are also available on our website at www.carismatx.com. Our website is not a part of this prospectus and is not incorporated by reference in this prospectus.
This prospectus is part of a registration statement 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 us and our consolidated subsidiaries and the securities we are offering. 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 these filings and the exhibits attached thereto. You should review the complete document to evaluate these statements.
INCORPORATION BY REFERENCE
The SEC allows us to “incorporateincorporate by reference”reference much of the information from other documents that we file with it,the SEC, which means that we can disclose important information to you by referring you to those publicly available documents. The information incorporatedthat we incorporate by reference in this prospectus is considered to be part of this prospectus. InformationBecause we are incorporating by reference future filings with the SEC, this prospectus is continually updated and those future filings may modify or supersede some of the information included or incorporated in this prospectus. This means that you must look at all of the SEC filings that we incorporate by reference to determine if any of the statements in this prospectus supersedes informationor in any document previously incorporated by reference thathave been modified or superseded. This prospectus incorporates by reference the documents listed below (File No. 001-36296) and any future filings we make with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934, as amended, or the Exchange Act (in each case, other than those documents or the portions of those documents not deemed to be filed) between the date of the initial registration statement and the effectiveness of the registration statement and following the effectiveness of the registration statement until the offering of the securities under the registration statement is terminated or completed:
•
Annual Report on Form 10-K for the fiscal year ended December 31, 2022, as filed with the SEC prior toon February 28, 2023, including the date of this prospectus.
We incorporateinformation specifically incorporated by reference into this prospectus and the registrationAnnual Report on Form 10-K from our definitive proxy statement for the 2023 Annual Meeting of which this prospectus is a part the information or documents listed below that we haveStockholders;
​
•
Current Reports on Form 8-K as filed with the SEC:SEC on January 30, 2023, January 31, 2023, February 1, 2023, February 2, 2023, February 7, 2023, February 14, 2023, February 27, 2023, March 2, 2023, March 6, 2023, March 8, 2023, and April 4, 2023; and
​
•
The description of our common stock contained in our registration statement on Form 8-A, as filed with the SEC under the Exchange Act on February 3, 2014, as the description therein has been updated and superseded by the description of our capital stock contained on Exhibit 4.1 to our Annual Report on Form 10-K for the fiscal year ended December 31, 2016, filed on March 24, 2017;
2022 and our Quarterly Reports on Form 10-Q for the quarters ended March 31, 2017, June 30, 2017 and September 30, 2017, filed on May 4, 2017, August 14, 2017 and November 17, 2017, respectively;
those portions of our Definitive Proxy Statement on Schedule 14A filed on April 7, 2017 that are deemed “filed” with the SEC;
our Current ReportsReport on Form 8-K (other than portions thereof furnished under Item 2.02 or Item 7.01 of Form 8-K and exhibits accompanying such reports that relate to such items)as filed with the SEC on January 6, 2017, March 6, 2017, April 3, 2017, May 1, 2017, May 22, 2017, June 12, 2017, September 22, 2017, October 13, 2017 (as amended on October 18, 2017)8, 2023, October 20, 2017, November 3, 2017, November 16, 2017 (including Item 2.02 and Exhibit 99.1), December 15, 2017, January 25, 2018 and March 13, 2018; and
the description of our capital stock contained in Form 8-A filed with the SEC on February 3, 2014, including any amendment or report filed for the purpose of updating such description.
In addition, all documents that we file with the SEC pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act after the date of the initial registration statement of which this prospectus is a part and prior to the effectiveness of such registration statement and all such documents that we file with the SEC after the date of this prospectus and before the termination of the offering of our securities shall be deemed incorporated by reference into this prospectus and to be a part of this prospectus from the respective dates of filing such documents.
Any statement contained in a document incorporated by reference in this prospectus shall be deemed to be modified or superseded for purposes of this prospectus to the extent that a statement contained in this prospectus or in any other subsequently filed document that also is or is deemed to be incorporated by reference in this prospectus modifies 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 this prospectus.​
You may request orally or in writing, a copy of any or all of the documents incorporated herein by reference. These documents will be provided to youthese filings, at no cost, by contacting: Eleven Biotherapeutics,writing or telephoning us at the following address or telephone number:
Carisma Therapeutics Inc., Attn: Chief Financial Officer, 245 First
3675 Market Street, Suite 1800, Cambridge, MA 02142. In addition, copies of any or all of the documents incorporated200
Philadelphia, PA 19104
Attn: Investor Relations
(267) 491-6422

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herein by reference may be accessed at our website at http://www.elevenbio.com. The information on such website is not incorporated by reference and is not a part of this prospectus.

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WHERE YOU CAN FIND MORE INFORMATION
​
​
[MISSING IMAGE: lg_carismatherapeutics-4c.jpg]
We file annual, quarterly and current reports, proxy statements and other information with the SEC. You may read and copy any document we file with the SEC at the SEC’s public reference room at 100 F Street NE, Room 1580, Washington, D.C. 20549. You may obtain information on the operation of the SEC’s public reference facilities by calling the SEC at 1-800-SEC-0330. You can request copies of these documents, upon payment of a duplicating fee, by writing to the SEC at its principal office at 100 F Street NE, Room 1580, Washington, D.C. 20549-1004. The SEC maintains an Internet website at http://www.sec.gov that contains reports, proxy and information statements, and other information regarding issuers that file electronically with the SEC. Our SEC filings are accessible through the Internet at that website. Our reports on Forms 10-K, 10-Q and 8-K, and amendments to those reports, are also available for download, free of charge, as soon as reasonably practicable after these reports are filed with the SEC, at our website at http://www.elevenbio.com. The content contained in, or that can be accessed through, our website is not a part of this prospectus.3,730,608 SHARES


COMMON STOCK
31​







$150,000,000
Debt Securities
Common Stock
Preferred Stock
Depositary Shares
Purchase Contracts
Purchase Units
Warrants



PROSPECTUS

​

           , 20182023
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TABLE OF CONTENTS




PART II
INFORMATION NOT REQUIRED IN PROSPECTUS
Item 14.   Other Expenses of Issuance and Distribution.
SetThe following table sets forth below is an estimate (except in the case of the registration fee) of the amount of fees andvarious expenses to be incurred in connection with the issuancesale and distribution of the offered securities being registered hereby, other than underwriting discounts and commission, if any, incurred in connection with the saleall of the offered securities. All such amountswhich will be borne by Eleven Biotherapeutics,Carisma Therapeutics Inc. (except any underwriting discounts, commissions, fees of underwriters, selling brokers or dealer managers and expenses incurred by the selling stockholders for brokerage, accounting, tax or legal services or any other expenses incurred by the selling stockholders in disposing of the shares). All amounts shown are estimates except the SEC registration fee.
     
  Amount to
be paid		 
SEC registration fee $18,675.00 
FINRA filing fees $(1) 
Printing expenses $(1) 
Accounting fees and expenses $(1) 
Legal fees and expenses $(1) 
Miscellaneous $(1) 
     
Total $(1) 
(1)These fees are calculated based on the securities offered and the number of issuances and accordingly cannot be estimated at this time.
​SEC registration fee​​​$1,152​​
​Legal fees and expenses​​​​50,000​​
​Accounting fees and expenses​​​​20,000​​
​Printing fees and expenses​​​​7,000​​
​Miscellaneous fees and expenses​​​​—​​
​Total expenses​​​$78,152​​
Item 15.   Indemnification of Directors and Officers.
Section 102 of the DGCL permits a corporation to eliminate the personal liability of its directors or its stockholders for monetary damages for a breach of fiduciary duty as a director, except where the director breached his or her duty of loyalty, failed to act in good faith, engaged in intentional misconduct or knowingly violated a law, authorized the payment of a dividend or approved a stock repurchase in violation of Delaware corporate law or obtained an improper personal benefit. OurThe registrant’s certificate of incorporation provides that no director shall be personally liable to usthe registrant or ourthe registrant’s stockholders for monetary damages for any breach of fiduciary duty as a director, notwithstanding any provision of law imposing such liability, except to the extent that the DGCL prohibits the elimination or limitation of liability of directors for breaches of fiduciary duty.
Section 145 of the DGCL provides that a corporation has the power to indemnify a director, officer, employee or agent of the corporation and certain other persons serving at the request of the corporation in related capacities against expenses (including attorneys’ fees), judgments, fines and amounts paid in settlements actually and reasonably incurred by the person in connection with an action, suit or proceeding to which he or she is or is threatened to be made a party by reason of such position, if such person acted in good faith and in a manner he or she reasonably believed to be in or not opposed to the best interests of the corporation, and, in any criminal action or proceeding, had no reasonable cause to believe his or her conduct was unlawful, except that, in the case of actions brought by or in the right of the corporation, no indemnification shall be made with respect to any claim, issue or matter as to which such person shall have been adjudged to be liable to the corporation unless and only to the extent that the Court of Chancery or other adjudicating court determines that, despite the adjudication of liability but in view of all of the circumstances of the case, such person is fairly and reasonably entitled to indemnification for such expenses which the Court of Chancery or such other court shall deem proper.
OurThe registrant’s certificate of incorporation provides that wethe registrant will indemnify each person who was or is a party or threatened to be made a party to any threatened, pending or completed action, suit or proceeding, whether civil, criminal, administrative

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or investigative (other than an action by or in the right of us)the registrant), by reason of the fact that he or she is or was, or has agreed to become, ourthe registrant’s director or officer, or is or was serving, or has agreed to serve, at ourthe registrant’s request as a director, officer, partner, employee or trustee of, or in a similar capacity with, another corporation, partnership, joint venture, trust or other enterprise (all such persons being referred to as an Indemnitee), or by reason of any action alleged to have been taken or omitted in such capacity, against all expenses (including attorneys’ fees), judgments, fines and amounts paid in settlement actually and reasonably incurred in connection with such action, suit or proceeding and any appeal therefrom if such Indemnitee acted in good faith and in a manner

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he or she reasonably believed to be in, or not opposed to, ourthe registrant’s best interests, and, with respect to any criminal action or proceeding, he or she had no reasonable cause to believe his or her conduct was unlawful.
OurThe registrant’s certificate of incorporation also provides that wethe registrant will indemnify any Indemnitee who was or is a party to an action or suit by or in the right of usthe registrant to procure a judgment in ourthe registrant’s favor by reason of the fact that the Indemnitee is or was, or has agreed to become, ourthe registrant’s director or officer, or is or was serving, or has agreed to serve, at ourthe registrant’s request as a director, officer, partner, employee or trustee or,of, or in a similar capacity with, another corporation, partnership, joint venture, trust or other enterprise, or by reason of any action alleged to have been taken or omitted in such capacity, against all expenses (including attorneys’ fees) and, to the extent permitted by law, amounts paid in settlement actually and reasonably incurred in connection with such action, suit or proceeding, and any appeal therefrom, if the Indemnitee acted in good faith and in a manner he or she reasonably believed to be in, or not opposed to, ourthe registrant’s best interests, except that no indemnification shall be made with respect to any claim, issue or matter as to which such person shall have been adjudged to be liable to us,the registrant, unless a court determines that, despite such adjudication but in view of all of the circumstances, he or she is entitled to indemnification of such expenses. Notwithstanding the foregoing, to the extent that any Indemnitee has been successful, on the merits or otherwise, he or she will be indemnified by usthe registrant against all expenses (including attorneys’ fees) actually and reasonably incurred by him or her or on his or her behalf in connection therewith. If we dothe registrant does not assume the defense, expenses must be advanced to an Indemnitee under certain circumstances.
We haveIn addition, the registrant has entered into indemnification agreements with our directorsall of the registrant’s executive officers and executive officers.directors. In general, these agreements provide that wethe registrant will indemnify the directorexecutive officer or executive officerdirector to the fullest extent permitted by law for claims arising in his or her capacity as aan executive officer or director or officer of our companythe registrant or in connection with theirhis or her service at ourthe registrant’s request for another corporation or entity. The indemnification agreements also provide for procedures that will apply in the event that a director oran executive officer or director makes a claim for indemnification and establish certain presumptions that are favorable to the directorexecutive officer or executive officer.director.
We maintainThe registrant maintains a general liability insurance policy that covers certain liabilities of ourthe registrant’s directors and officers arising out of claims based on acts or omissions in their capacities as directors or officers.
Insofar as the forgoing provisions permit indemnification of directors, executive officers, or persons controlling us for liability arising under the Securities Act of 1933, as amended, or the Securities Act, we have been informed that, in the opinion of the SEC, such indemnification is against public policy as expressed in the Securities Act and is therefore unenforceable.

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Item 16.   Exhibits.Exhibits
Exhibit Index
Exhibit No.​​Description​
​​2.1​​​Agreement and Plan of Merger and Reorganization, dated as of September 20, 2022, by and among Sesen Bio, Inc., Seahawk Merger Sub, Inc., and CARISMA Therapeutics Inc. (incorporated by reference to Exhibit 2.1 to the registrant’s Current Report on Form 8-K (File No. 001-36296) filed on September 21, 2022)​
  1.1*​​2.2​​​First Amendment to Agreement and Plan of Merger and Reorganization, dated as of
December 29, 2022, by and among Sesen Bio, Inc., Seahawk Merger Sub, Inc., and CARISMA
Therapeutics, Inc. (incorporated by reference to Exhibit 2.1 to the registrant’s Current Report
on Form of Underwriting Agreement.8-K (File No. 001-36296) filed on December 29, 2022)		​
​​2.3​​​Second Amendment to Agreement and Plan of Merger and Reorganization, dated as of February 13, 2023, by and among Sesen Bio, Inc., Seahawk Merger Sub, Inc., and CARISMA Therapeutics, Inc. (incorporated by reference to Exhibit 2.1 to the registrant’s Current Report on Form 8-K (File No. 001-36296) filed on February 14, 2023)​
​​4.1​
​
​Restated Certificate of Incorporation of Eleven Biotherapeutics,Carisma Therapeutics Inc., dated March 7, 2023 (incorporated herein by reference to Exhibit 3.1 to the Company’sregistrant’s Current Report on Form 8-K (File No. 001-36296) filed on February 18, 2014).March 8, 2023)​

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Exhibit No.​​Description​
​​
4.2​
​
​Amended and Restated BylawsBy-Laws of Eleven Biotherapeutics,Carisma Therapeutics Inc., as amendeddated March 7, 2023 (incorporated herein by reference to Exhibit 3.13.2 to the Company’sregistrant’s Current Report on Form 8-K (File No. 001-36296) filed on April 16, 2015).March 8, 2023)​
​​
4.3​
​
​Specimen Stock Certificate evidencingAmended and Restated Subscription Agreement, dated as of December 29, 2022, by and
between Carisma and each of the shares of common stockpurchasers listed on the signature pages thereto, severally and
not jointly (incorporated herein by reference to Exhibit 4.110.35 to the Company’s Registration Statement registrant’s registration statement
on Form S-1/S-4/A (No. 333-267891) filed on January 23, 2014 (Reg. No. 333-193131)).10, 2023)		​
​​4.4
  4.4*​​Form of any Certificate of Designation setting forth the preferences and rights with respect to any preferred stock issued hereunder.​
  4.5
Registration Rights Agreement, dated as of September 20, 2016 by and among Eleven Biotherapeutics, Inc. and the shareholders named thereinMarch 7, 2023 (incorporated herein by reference to Exhibit 4.1 10.4
to the Company’sregistrant’s Current Report on Form 8-K (File No. 001-36296) filed on September 21, 2016 (File No. 001-36296)).

2022)		​
​​
  4.65.1*​
Amended and Restated Investors’ Rights Agreement of Eleven Biotherapeutics, Inc. (incorporated herein by reference to Exhibit 4.2 to the Company’s Registration Statement on Form S-1/A filed with the SEC on January 23, 2014 (Reg. No. 333-193131)).
​
  4.7
Form of Warrant issued to Silicon Valley Bank and Life Science Loans, LLC dated November 25, 2014 (incorporated herein by reference to Exhibit 10.23 to the Company’s Registration Statement on Form S-1 filed on December 19, 2014 (Reg. No. 333-201176)).
  4.8
Form of Common Warrant (incorporated herein by reference to Exhibit 4.1 to the Company’s Current Report on Form 8-K filed with the SEC on November 3, 2017 (File. No. 001-36296)).
  4.9
Form of Senior Indenture (incorporated herein by reference to Exhibit 4.3 to the Company’s Registration Statement on Form S-3 filed on March 12, 2015 (File No. 333-202676)).
  4.10
Form of Subordinated Indenture (incorporated herein by reference to Exhibit 4.4 to the Company’s Registration Statement on Form S-3 filed on March 12, 2015 (File No. 333-202676)).
  4.11
Form of Senior Note (incorporated herein by reference to Exhibit 4.5 to the Company’s Registration Statement on Form S-3 filed on March 12, 2015 (File No. 333-202676)).
  4.12
Form of Subordinated Note (incorporated herein by reference to Exhibit 4.6 to the Company’s Registration Statement on Form S-3 filed on March 12, 2015 (File No. 333-202676)).
  4.13*Form of Deposit Agreement.
  4.14*Form of Warrant Agreement.
  4.15*Form of Purchase Contract Agreement.
  4.16*Form of Purchase Unit Agreement.
  5.1​
Opinion of Hogan Lovells US LLP.Wilmer Cutler Pickering Hale and Dorr LLP
​
​​23.1*​​​
Consent of KPMG LLP, independent registered public accounting firm
​
  12.1*​​Computation of Ratio of Earnings to Fixed Charges.23.2*
​​
  23.1​
Consent of Ernst & Young LLP, Independent Registered Public Accounting Firm.independent registered public accounting firm
​
​​23.3*
  23.2​​​
Consent of PricewaterhouseCoopers LLP, Independent Registered Accounting Firm.
  23.3
Consent of Hogan Lovells USWilmer Cutler Pickering Hale and Dorr LLP (included in ExhibitsExhibit 5.1).
​
​​
24.1*​​​
PowerPowers of Attorney (included onin the signature page hereto).pages to the registration statement)
​
​​

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107*​​
  25.1**Form T-1 Statement of Eligibility and Qualification under the Trust Indenture Act of 1939 of Trustee for Form of Indenture.
  99.1​
Audited consolidated financial statements of Viventia Bio Inc. (incorporated herein by reference to Exhibit 99.1 to the Company’s Current Report on Form 8-K/A filed on December 6, 2016 (File No. 001-36296)).Filing Fee Table
  99.2
Unaudited interim consolidated financial statements of Viventia Bio Inc. (incorporated herein by reference to Exhibit 99.2 to the Company’s Current Report on Form 8-K/A filed on December 6, 2016 (File No. 001-36296)).
*To be filed by amendment or as an exhibit to a report pursuant to Section 13(a), 13(c) or 15(d) of the Exchange Act.​

​
**To be filed in accordance with the requirements of Section 305(b)(2) of the Trust Indenture Act of 1939 and Rule 5b-3 thereunder.
*
Filed herewith
​
Item 17.   Undertakings.
(a)The undersigned registrant hereby undertakes:
(1)To file, during any period in which offers or sales are being made, a post-effective amendment to this registration statement:
(i)To include any prospectus required by section 10(a)(3) of the Securities Act of 1933;
(ii)To reflect in the prospectus any facts or events arising after the effective date of the registration statement (or the most recent post-effective amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information in the registration statement. Notwithstanding the foregoing, any increase or decrease in volume of securities offered (if the total dollar value of securities offered would not exceed that which was registered) and any deviation from the low or high end of the estimated maximum offering range may be reflected in the form of prospectus filed with the SEC pursuant to Rule 424(b) if, in the aggregate, the changes in volume and price represent no more than a 20% change in the maximum aggregate offering price set forth in the “Calculation of Registration Fee” table in the effective registration statement; and
(iii)To include any material information with respect to the plan of distribution not previously disclosed in the registration statement or any material change to such information in the registration statement;
The undersigned registrant hereby undertakes:
(a)(1)
To file, during any period in which offers or sales are being made, a post-effective amendment to this registration statement:
​
(i)
to include any prospectus required by Section 10(a)(3) of the Securities Act;
​
(ii)
to reflect in the prospectus any facts or events arising after the effective date of this registration statement (or the most recent post-effective amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information set forth in this registration statement. Notwithstanding the foregoing, any increase or decrease in volume of securities offered (if the total dollar value of securities offered would not exceed that which was registered) and any deviation from the low or high end of the estimated maximum offering range may be reflected in the form of prospectus filed with the Commission pursuant to Rule 424(b) if, in the aggregate, the changes in volume and price represent no more than a 20 percent change in the maximum aggregate offering price set forth in the “Calculation of Registration Fee” table in the effective registration statement; and
​
(iii)
to include any material information with respect to the plan of distribution not previously disclosed in this registration statement or any material change to such information in this registration statement;
​
provided, however, that paragraphs (a)(1)(i), (a)(1)(ii) and (a)(1)(iii) do not apply if the information required to be included in a post-effective amendment by those paragraphs is contained in reports filed with or furnished to the SECCommission by the registrant pursuant to Section 13 or Section 15(d) of the Exchange Act, that are incorporated by reference in thethis registration statement, or is contained in a form of prospectus filed pursuant to Rule 424(b) that is part of thethis registration statement.
(2)
That, for the purpose of determining any liability under the Securities Act of 1933, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.
(3)To remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the offering.

II-4That, for the purpose of determining any liability under the Securities Act, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at the time shall be deemed to be the initial bona fide offering thereof.
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(5)That, for the purpose of determining liability under the Securities Act of 1933 to any purchaser:
(i)Each prospectus filed by the registrant pursuant to Rule 424(b)(3) shall be deemed to be part of the registration statement as of the date the filed prospectus was deemed part of and included in the registration statement; and
(ii)Each prospectus required to be filed pursuant to Rule 424(b)(2), (b)(5) or (b)(7) as part of a registration statement in reliance on Rule 430B relating to an offering made pursuant to Rule 415(a)(1)(i), (vii) or (x) for the purpose of providing the information required by Section 10(a) of the Securities Act shall be deemed to be part of and included in the registration statement as of the earlier of the date such form of prospectus is first used after effectiveness or the date of the first contract of sale of securities in the offering described in the prospectus. As provided in Rule 430B, for liability purposes of the issuer and any person that is at that date an underwriter, such date shall be deemed to be a new effective date of the registration statement relating to the securities in the registration statement to which the prospectus relates, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof. Provided, however, that no statement made in a registration statement or prospectus that is part of the registration statement or made in a document incorporated or deemed incorporated by reference into the registration statement or prospectus that is part of the registration statement will, as to a purchaser with a time of contract of sale prior to such effective date, supersede or modify any statement that was made in the registration statement or prospectus that was part of the registration statement or made in any such document immediately prior to such effective date; or
(6)That, for the purpose of determining liability of the registrant under the Securities Act to any purchaser in the initial distribution of the securities, the undersigned registrant undertakes that in a primary offering of securities of the undersigned registrant pursuant to this registration statement, regardless of the underwriting method used to sell the securities to the purchaser, if the securities are offered or sold to such purchaser by means of any of the following communications, the undersigned registrant will be a seller to the purchaser and will be considered to offer or sell such securities to such purchaser:
(i)Any preliminary prospectus or prospectus of the undersigned registrant relating to the offering required to be filed pursuant to Rule 424;
(ii)Any free writing prospectus relating to the offering prepared by or on behalf of the undersigned registrant or used or referred to by the undersigned registrant;
(iii)The portion of any other free writing prospectus relating to the offering containing material information about the undersigned registrant or its securities provided by or on behalf of the undersigned registrant; and
(iv)Any other communication that is an offer in the offering made by the undersigned registrant to the purchaser.
(b)The undersigned registrant hereby undertakes that, for purposes of determining any liability under the Securities Act, each filing of the registrant’s annual report pursuant to Section 13(a) or 15(d) of the Exchange Act (and, where applicable, each filing of an employee benefit plan’s annual report pursuant to Section 15(d) of the Exchange Act) that is incorporated by reference in the registration statement shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.
(h)Insofar as indemnification for liabilities arising under the Securities Act of 1933 may be permitted to directors, officers and controlling persons of the registrant pursuant to the foregoing provisions, or otherwise, the registrant has been advised that in the opinion of the Securities and Exchange Commission such indemnification
(3)
II-5To remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the offering.

​
(4)
That, for the purpose of determining liability under the Securities Act to any purchaser:
​
(i)
each prospectus filed by the registrant pursuant to Rule 424(b)(3) shall be deemed to be part of the registration statement as of the date the filed prospectus was deemed part of and included in the registration statement; and
​
(ii)
each prospectus required to be filed pursuant to Rule 424(b)(2), (b)(5), or (b)(7) as part of a registration statement in reliance on Rule 430B relating to an offering made pursuant to Rule 415(a)(1)(i), (vii) or (x) for the purpose of providing the information required by Section 10(a) of the Securities Act shall be deemed to be part of and included in the registration statement as of the earlier of the date such form of prospectus is first used after effectiveness or the date of the first contract of sale of securities in the offering described in the prospectus. As provided in Rule 430B, for liability purposes of the issuer and any person that is at that date an underwriter, such date shall be deemed to be a new effective date of the registration statement relating to the securities in the registration statement to which that prospectus relates, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof; provided, however, that no statement made in a registration statement or prospectus that is part of the registration statement or made in a document incorporated or deemed incorporated by reference into the registration statement or prospectus that is part of the registration statement will, as to a purchaser with a time of contract of sale prior to such effective date, supersede or modify any statement that was made in the registration statement or prospectus that was part of the registration statement or made in any such document immediately prior to such effective date.
​
(b)
The undersigned registrant hereby undertakes that, for purposes of determining any liability under the Securities Act, each filing of the registrant’s annual report pursuant to Section 13(a) or 15(d) of the Exchange Act (and, where applicable, each filing of an employee benefit plan’s annual report pursuant to Section 15(d) of the Exchange Act) that is incorporated by reference in this registration statement shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.
​
(c)
Insofar as indemnification for liabilities arising under the Securities Act may be permitted to directors, officers and controlling persons of the registrant pursuant to the indemnification provisions described herein, or otherwise, the registrant has been advised that in the opinion of the Commission such indemnification is against public policy as expressed in the Securities Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrant of expenses incurred or paid by a director, officer or controlling person of the registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Securities Act and will be governed by the final adjudication of such issue.
(j)The undersigned registrant hereby undertakes to file an application for the purpose of determining the eligibility of the trustee to act under subsection (a) of Section 310 of the Trust Indenture Act in accordance with the rules and regulations prescribed by the SEC under Section 305(b)(2) of the Act.

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SIGNATURES
SIGNATURES
Pursuant to the requirements of the Securities Act of 1933, the Registrantregistrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-3 and has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the towncity of Cambridge, thePhiladelphia, Commonwealth of Massachusetts,Pennsylvania, on March 16, 2018.April 17, 2023.
​​​​CARISMA THERAPEUTICS INC.​
​​
​​
ELEVEN BIOTHERAPEUTICS, INC.
By:​​/s/ Stephen A. HurlySteven Kelly​
​​  Stephen A. Hurly​​​​​Steven Kelly​
​​​​​​​President and Chief Executive Officer​
SIGNATURES AND POWER OF ATTORNEY

Each ofWe, the undersigned officers and directors and officers of Eleven Biotherapeutics,Carisma Therapeutics Inc. hereby constitutesseverally constitute and appointsappoint Steven Kelly, Richard Morris and Thomas Wilton, and each of Stephen A. Hurly and Richard F. Fitzgerald of Eleven Biotherapeutics, Inc., his or herthem singly, our true and lawful attorneys-in-fact and agents with full power to any of substitutionthem, and resubstitution,to each of them singly, to sign for him or herus and in his or her name, placeour names in the capacities indicated below the registration statement on Form S-3 filed herewith and stead, in any and all capacities, to execute any and all amendments (including post-effective amendments) to thissaid registration statement, to sign any registration statement related to this registration statement filed pursuant to Rule 462(b) of the Securities Act of 1933, and to file or cause the same to be filed the same, with all exhibits thereto and allother documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorneys-in-fact and agents, and each of them, full power and authoritygenerally to do all such things in our name and perform eachon our behalf in our capacities as officers and every actdirectors to enable Carisma Therapeutics Inc. to comply with the provisions of the Securities Act of 1933, as amended, and thing requisiteall requirements of the Securities and desirable to be done in and about the premises as fully and to all intents and purposes as the undersigned might or could do in person,Exchange Commission, hereby ratifying and confirming all acts and things that said attorneys-in-factattorneys, and agents or anyeach of them, or their or his or her substitute or substitutes, may lawfullyshall do or cause to be done by virtue hereof.
Pursuant to the requirements of the Securities Act of 1933, as amended, this registration statement has been signed by the following persons in the capacities and on the dates indicated.
​
Signature​​Title​​Date​
​
/s/ Stephen A. HurlySteven Kelly
​
Steven Kelly
​Director, ​President, and Chief Executive Officer, (PrincipalDirector
(Principal Executive Officer)		March 16, 2018​​April 17, 2023​
Stephen A. Hurly​
/s/ Richard F. FitzgeraldMorris
​
Richard Morris
​​Chief Financial Officer (Principal
(Principal Financial and Accounting Officer)		March 16, 2018​​April 17, 2023​
Richard F. Fitzgerald​
/s/ Wendy L. Dixon, Ph.D.Sanford Zweifach
​
Sanford Zweifach
​​Director and Chair of the Board of DirectorsMarch 16, 2018​​April 17, 2023​
Wendy L. Dixon, Ph.D.​
/s/ Abbie C. CelnikerRegina Hodits, Ph.D.
​
Regina Hodits, Ph.D.
​​DirectorMarch 16, 2018​​April 17, 2023​
Abbie C. Celniker, Ph.D.​
/s/ Paul G. ChaneyBriggs Morrison, M.D.
​
Briggs Morrison, M.D.
​​DirectorMarch 16, 2018​​April 17, 2023​
Paul G. Chaney​
/s/ Leslie DanBjörn Odlander, M.D.
​
Björn Odlander, M.D.
​​DirectorMarch 16, 2018​​April 17, 2023​
Leslie Dan​
/s/ Jay S. Duker, M.D.Michael Torok
​
Michael Torok
​​DirectorMarch 16, 2018​​April 17, 2023​
Jay S. Duker, M.D.​
/s/ Barry J. Gertz, M.D., Ph.D.Chidozie Ugwumba
​
Chidozie Ugwumba
​​DirectorMarch 16, 2018
Barry J. Gertz, M.D., Ph.D.​​April 17, 2023
/s/    Jane V. HendersonDirectorMarch 16, 2018
Jane V. Henderson
/s/    Daniel S. LynchDirectorMarch 16, 2018
Daniel S. Lynch​


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