As filed with the Securities and Exchange Commission on August 9, 2017.June 26, 2020

RegistrationNo. 333-            

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington,WASHINGTON, D.C. 20549

FORM S-3

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

ZAFGEN, INC.Larimar Therapeutics, Inc.

(Exact name of registrant as specified in its charter)

175 Portland Street, 4th FloorThree Bala Plaza East, Suite 506

Boston, Massachusetts 02114Bala Cynwyd, PA 19004

(484)414-2700

(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)

(617)Carole622-4003Ben-Maimon, M.D.

(Registrant’s telephone number, including area code)

Thomas E. Hughes, Ph.D.

President and Chief Executive Officer

Zafgen,Larimar Therapeutics, Inc.

175 Portland Street, 4th FloorThree Bala Plaza East, Suite 506

Boston, Massachusetts 02114Bala Cynwyd, PA 19004

(617)(484)622-4003414-2700

(Name, address, including zip code, and telephone number, including area code, of agent for service)

With copiesCopies to:

Mitchell S. Bloom,Rachael M. Bushey, Esq.

Laurie A. Burlingame,Jennifer L. Porter, Esq.

Goodwin ProcterPepper Hamilton LLP

100 Northern Avenue3000 Two Logan Square

Boston, Massachusetts 02210Eighteenth and Arch Streets

(617)570-1000Philadelphia, PA 19103

(215) 981-4000

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

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, as amended, or Securities Act, other than securities offered only in connection with dividend or interest reinvestment plans, check the following box:  ☒

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 Formform 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, anon-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company” and “emerging growth company” inRule 12b-2 of the Exchange Act of 1934, as amended.Act.

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.  ☒

CALCULATION OF REGISTRATION FEE

THE REGISTRANT HEREBY AMENDS THIS REGISTRATION STATEMENT ON SUCH DATE OR DATES AS MAY BE NECESSARY TO DELAY ITS EFFECTIVE DATE UNTIL THE REGISTRANT SHALL FILE A FURTHER AMENDMENT WHICH SPECIFICALLY STATES THAT THIS REGISTRATION STATEMENT SHALL THEREAFTER BECOME EFFECTIVE IN ACCORDANCE WITH SECTION

The registrant hereby amends this registration statement on such date or dates as may be necessary to delay its effective date until the registrant shall file a further amendment that specifically states that this registration statement shall thereafter become effective in accordance with Section 8(a) OF THE SECURITIES ACT OFof the Securities Act of 1933 AS AMENDED, OR UNTIL THE REGISTRATION STATEMENT SHALL BECOME EFFECTIVE ON SUCH DATE AS THE COMMISSION ACTING PURSUANT TO SAID SECTIONor until the registration statement shall become effective on such date as the Securities and Exchange Commission, acting pursuant to said Section 8(a), MAY DETERMINE.may determine.

The information contained in this preliminary prospectus is not complete and may be changed. TheseA registration statement relating to these securities may not be sold until the registration statementhas been filed with the Securities and Exchange Commission. The selling stockholders may not sell these securities until the Securities and Exchange Commission isdeclares the registration statement effective. This preliminary prospectus is not an offer to sell nor doesthese securities and it seekis not soliciting an offer to buy these securities in any jurisdiction where the offer or sale is not permitted.

SUBJECT TO COMPLETION,

DATED AUGUST 9, 2017.JUNE 26, 2020.

PROSPECTUS

$150,000,000

12,860,272 Shares of Common Stock

Preferred Stock

Debt Securities

Warrants

Units

WeThis prospectus of Larimar Therapeutics, Inc. (formerly known as Zafgen, Inc.), a Delaware corporation, or Larimar, relates to the offering and resale by the selling stockholders identified herein of up to 12,860,272 shares of common stock of Larimar, par value $0.001 per share, or Common Stock. The shares offered by the selling stockholders consist of:

The shares of Common Stock described in this prospectus or in any supplement to this prospectus may be sold from time to time issue,pursuant to this prospectus by the selling stockholders in oneordinary brokerage transactions, in transactions in which brokers solicit purchases, in negotiated transactions, or more seriesin a combination of such methods of sale, at market prices prevailing at the time of sale, at prices related to such prevailing market prices, at fixed prices or classes, upprices subject to $150,000,000change, or at negotiated prices. See “Selling Stockholders” and “Plan of Distribution.” We cannot predict when or in aggregate principal amountwhat amounts the selling stockholders may sell any of the shares offered by this prospectus.

We are not selling any shares of our common stock, preferred stock, debt securities, warrants and/or units. We may offer these securities separately or together in units. WeCommon Stock, and we will specify in the accompanying prospectus supplement the termsnot receive any of the securities being offered.proceeds from the sale of shares by the selling stockholders. The selling stockholders will pay all brokerage fees and commissions and similar sale-related expenses. We may sell these securitiesare only paying expenses relating to or through underwriters and also to other purchasers or through agents. We will set forth the names of any underwriters or agents, and any fees, conversions, or discount arrangements, in the accompanying prospectus supplement. We may not sell any securities under this prospectus without deliveryregistration of the applicable prospectus supplement.

You should read this documentshares with the U.S. Securities and Exchange Commission. The registration of the shares of our Common Stock does not necessarily mean that any prospectus supplementof such shares will be offered or amendment carefully before you invest in our securities.sold by the selling stockholders.

Our common stockCommon Stock is listed on The NASDAQthe Nasdaq Global Market under the symbol “ZFGN.“LRMR.” On August 7, 2017, the closingThe last reported sale price forof our common stock, as reportedCommon Stock on The NASDAQ Global Market,June 25, 2020 was $3.49$14.04 per share. Our principal executive offices are located at 175 Portland Street, 4th Floor, Boston, Massachusetts 02114.

Investing in our securities involves a high degree of risk. You should review carefully the risks and uncertainties described under the headingINVESTING IN OUR SECURITIES INVOLVES RISKS. SEE THE “Risk FactorsRISK FACTORS” contained in this prospectus beginning on page 4 and any applicable prospectus supplement, and under similar headings in the other documents that are incorporated by reference into this prospectus.BEGINNING ON PAGE 5 OF THIS PROSPECTUS AND ANY SIMILAR SECTION CONTAINED IN THE APPLICABLE PROSPECTUS SUPPLEMENT OR ANY DOCUMENTS THAT ARE INCORPORATED BY REFERENCE INTO THIS PROSPECTUS BEFORE INVESTING IN OUR SECURITIES

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

The date of this Prospectus is                , 2017.NEITHER THE SECURITIES AND EXCHANGE COMMISSION NOR ANY STATE SECURITIES COMMISSION HAS APPROVED OR DISAPPROVED OF THESE SECURITIES OR DETERMINED IF THIS PROSPECTUS IS TRUTHFUL OR COMPLETE. ANY REPRESENTATION TO THE CONTRARY IS A CRIMINAL OFFENSE.

Prospectus dated             , 2020

TABLE OF CONTENTS

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ABOUT THIS PROSPECTUS

This prospectus is part of a registration statement on Form S-3 that we filed with the Securities and Exchange Commission, or SEC, pursuant to which the SEC, using a “shelf” registration process. Under this shelf registration process, weselling stockholders named herein may, from time to time, offer and sell any combinationor otherwise dispose of the securities describedshares of our common stock covered by this prospectus. If required, each time a selling stockholder offers common stock, in addition to this prospectus, in one or more offerings for an aggregate offering price of up to $150,000,000.

This prospectus provideswe may provide you with a general description of the securities we may offer. Each time we sell securities, we will provide one or more prospectus supplementssupplement that will contain specific information about the terms of thethat offering. TheWe may also authorize one or more free writing prospectuses to be provided to you that may contain material information relating to that offering. We may also use a prospectus supplement may alsoand any related free writing prospectus to add, update or change any of the information contained in this prospectus. prospectus or in documents we have incorporated by reference.

You should read bothnot assume that the information contained in this prospectus is accurate on any date subsequent to the date set forth on the front cover of this prospectus or that any information we have incorporated by reference is correct on any date subsequent to the date of the document incorporated by reference, even though this prospectus is delivered or shares of common stock are sold or otherwise disposed of on a later date. It is important for you to read and consider all information contained in this prospectus, including the accompanying prospectus supplement together withdocuments incorporated by reference therein, in making your investment decision. You should also read and consider the additional information describedin the documents to which we have referred you under the headingcaptions “Where You Can Find MoreAdditional Information” beginning on page 34 ofand “Information Incorporated by Reference” in this prospectus.

You should rely only onNeither we nor the selling stockholders have authorized any dealer, agent or other person to give any information or to make any representation other than those contained in or incorporated by reference in this prospectus and any accompanying prospectus supplement or related 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 related free writing prospectus. This prospectus and any accompanying prospectus supplement or related free writing prospectus, filed by us with the SEC. We have not authorized anyone to provide you with different information. This prospectus and the accompanying prospectus supplementif any, do not constitute an offer to sell or the solicitation of an offer to buy any securities other than the registered securities described in theto which they relate, nor does this prospectus and any accompanying prospectus supplement or related free writing prospectus, if any, constitute an offer to sell or the solicitation of an offer to buy such securities in any circumstances in whichjurisdiction to any person to whom it is unlawful to make such offer or solicitation is unlawful. You should assumein such jurisdiction.

This prospectus incorporates by reference, and any prospectus supplement or free writing prospectus may contain and incorporate by reference, market data and industry statistics and forecasts that are based on independent industry publications and other publicly available information. Although we believe these sources are reliable, we do not guarantee the accuracy or completeness of this information appearingand we have not independently verified this information. In addition, the market and industry data and forecasts that may be included or incorporated by reference in this prospectus, any prospectus supplement or any applicable free writing prospectus may involve estimates, assumptions and other risks and uncertainties and are subject to change based on various factors, including those discussed under the heading “Risk Factors” contained in this prospectus, the applicable prospectus supplement and any applicable free writing prospectus, and under similar headings in other documents that are incorporated by reference into this prospectus. Accordingly, investors should not place undue reliance on this information.

Unless the context otherwise requires, references in this prospectus to “Larimar,” the “Company,” “we,” “our” or “us” refer to Larimar Therapeutics, Inc. (formerly known as Zafgen, Inc.) and its subsidiaries, references to “Zafgen” refer to the Company prior to the completion of the Merger, references to “Chondrial” refer to Chondrial Therapeutics, Inc., a privately held corporation prior to the completion of the Merger, and references to “Merger Subsidiary” refer to Zordich Merger Sub, Inc., the Company’s wholly owned subsidiary following the Merger.

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RISK FACTORS

Investing in our securities involves a high degree of risk. You should carefully consider the risk factors set forth under “Risk Factors” in (i) our Annual Report on Form10-K for the year ended December 31, 2019, (ii) our Quarterly Report on Form10-Q for the three months ended March 31, 2020 and (iii) our current report on Form8-K/A filed on June 26, 2020, each of which is incorporated by reference in this prospectus, together with all other information contained or incorporated by reference in this prospectus, as updated by our subsequent filings under the Exchange Act, and the risk factors and other information contained in any applicable prospectus supplement, before deciding whether to purchase any of the securities being registered pursuant to the registration statement of which this prospectus is a part. The risks described below and uncertainties we describe in the documents incorporated by reference in this prospectusherein are not the only ones we face. Additional risks and any prospectus supplement,uncertainties not presently known to us could adversely affect our business, operating results and financial condition, as well as other information we include or incorporate by reference into this prospectus and any applicable prospectus supplement, before makingadversely affect the value of an investment decision. Our business, financial condition or results of operations could be materially adversely affected by the materialization of any of these risks. The trading price ofin our securities, could decline due toand the materializationoccurrence of any of these risks andmight cause you mayto lose all or part of your investment.

Risks Related to this Offering

The number of shares being registered for sale is significant in relation to the number of outstanding shares of our Common Stock.

We have filed a registration statement of which this prospectus is a part to register the shares offered hereunder for sale into the public market by the selling stockholders. Upon registration of the shares of common stock offered hereunder, 6,769,022 shares of the common stock registered hereunder may be resold in the public market immediately without restriction. The remaining 6,091,250 shares of the common stock registered hereunder are currently restricted as a result oflock-up agreements but will be freely tradeable 180 days after May 28, 2020, the closing date of the Merger. These shares represent a large number of shares of our common stock, and if sold in the market all at once or at about the same time, could depress the market price of our common stock during the period the registration statement remains effective and could also affect our ability to raise equity capital.

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CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus and the documents incorporated herein by reference also contain forward-looking statements that involve risks and uncertainties. Actual results could differ materially from those anticipated in these forward-looking statements as a result of certain factors, including the risks described below and in the documents incorporated herein by reference, including (i) our annual report onForm 10-K for the fiscal year ended December 31, 2016, which is on file with the SEC and is incorporated herein by reference, (ii) our quarterly reports on Form10-Q for the quarters ended March 31, 2017 and June 30, 2017, which are on file with the SEC and are incorporated herein by reference, and (iii) other documents we file with the SEC that are deemed incorporated by reference into this prospectus.

CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS

This prospectus including the documents that we incorporate by reference, containsmay contain forward-looking statements within the meaning of Section 27A of the Securities Act, and Section 21E of the Securities Exchange Act, about us and our subsidiaries. These forward-looking statements are intended to be covered by the safe harbor for forward-looking statements provided by the Private Securities Litigation Reform Act of 1934, as amended, or the Exchange Act. Any1995. Forward-looking statements about our expectations, beliefs, plans, objectives, assumptions or future events or performance are not statements of historical factsfact, and maycan be forward-looking. These statements are often, but are not always, made throughidentified by the use of words or phrasesforward-looking terminology such as “anticipate,“believes,” “believe,“expects,” “contemplate,“may,” “continue,“will,” “could,” “estimate,“should,” “expect,“projects,” “intend,“plans,” “may,“goal,” “plan,“targets,” “potential,” “predict,“estimates,” “project,“pro forma,” “seek,“seeks,” “should,” “target,” “will,” “would,” and similar expressions,“intends” or “anticipates” or the negative of these terms,thereof or similar expressions. Accordingly, these statements involve estimates, assumptions and uncertainties which could cause actual results to differ materially from those expressed in them. Any forward-looking statements are qualified in their entirety by reference to the factors discussed throughout this prospectus, and in particular those factors referenced in the section “Risk Factors.”

This prospectus contains forward-looking statements that are based on our management’s belief and assumptions and on information currently available to our management. These statements relate to future events or our future financial performance, and involve known and unknown risks, uncertainties and other factors that may cause our actual results, levels of activity, performance or achievements to be materially different from any future results, levels of activity, performance or achievements expressed or implied by these forward-looking statements.comparable terminology. Forward-looking statements include, but are not limited to, statements about:concerning:

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THE COMPANY

We are a biopharmaceutical company dedicated to significantly improving the health and well-being of patients affected by metabolic diseases including type 2 diabetes and obesity. We are focused on developing novel therapeutics that treat the underlying biological mechanisms through the methionine aminopeptidase 2, or MetAP2, pathway. We have pioneered the study of MetAP2 inhibitors in both common and rare forms of obesity. Our lead product candidate isZGN-1061, a novel fumagillin-class MetAP2 inhibitor administered by subcutaneous injection, which is currently being profiled for its utility in the treatment of metabolic diseases including type 2 diabetes and obesity. We have completed a Phase 1 clinical trial ofZGN-1061 in the Netherlands, which was comprised of a single ascending dose, or SAD, portion and a multiple ascending dose, or MAD, portion. This clinical trial evaluatedZGN-1061 for safety, tolerability and pharmacokinetics while also gaining an early indication of efficacy over four weeks of treatment. We reported positive top line results from this clinical trial in May 2017 and presented the full data package at the American Diabetes Association’s 77th Annual Scientific Sessions in June2017. ZGN-1061 demonstrated rapid drug absorption and clearance in line with criteria established in advance for the molecule, and has a favorable safety profile, with no evidence of prothrombotic effects. The data show thatZGN-1061 treatment causes improvements across multiple metabolic measures consistent with MetAP2 inhibition, and patients in the clinical trial experienced mean weight loss of up to approximately one pound per week. We plan to advanceZGN-1061 into a Phase 2 clinical trial in patients with type 2 diabetes who are overweight or obese, in Australia and New Zealand in the third quarter of 2017.

ZGN-1061 acts through potent inhibition of MetAP2, an enzyme that modulates the activity of key cellular processes that control metabolism. MetAP2 inhibitors work, at least in part, by directing MetAP2 binding to cellular stress and growth factor mediators, thereby reducing the tone of signals that drive lipid synthesis by the liver and fat storage throughout the body. In this manner, MetAP2 inhibition serves the purpose ofre-establishing balance to the ways the body stores and metabolizes fat and glucose. MetAP2 inhibitors reduce the production of new fatty acid molecules by the liver and help convert stored fats into useful energy, while reducing hunger. In animal models that mimic aspects of type 2 diabetes, these processes lead to improvement of glycemic control independent of weight loss.

ZGN-1061 was discovered by our researchers as part of a multi-year campaign to identify novel compounds for development in the treatment of type 2 diabetes, and that avoided limitingpre-clinical safety concerns observed with beloranib, including teratogenicity and effects on testicular function. To date, the compound has similar efficacy, potency, and range of activity in animal models as beloranib, but displays highly differentiated properties and improved safety margins inpre-clinical studies, supporting the value of the compound as a more highly optimized MetAP2 inhibitor. Further, the compound displays improved safety margins innon-clinical safety studies relative to beloranib for effects on coagulation in dogs, an effect that correlates with reduced impact on endothelial cell proliferationin vitro.

We own various U.S. federal trademark registrations and applications, and unregistered trademarks, including our corporate name and our corporate logo.

Our principal executive offices are located at 175 Portland Street, 4th Floor, Boston, Massachusetts 02114 and our telephone number is (617)622-4003.

RATIO OF EARNINGS TO FIXED CHARGES

The following table sets forth our ratio of earnings to fixed charges for the periods shown. You should read this table in conjunction withprospectus and the consolidated financial statements and notesdocuments incorporated by reference completely and with the understanding that our actual future results may be materially different from what we currently expect. Our business and operations are and will be subject to a variety of risks, uncertainties and other factors. Consequently, actual results and experience may materially differ from those contained in any forward-looking statements. Such risks, uncertainties and other factors that could cause actual results and experience to differ from those projected include, but are not limited to, the risk factors discussed under the heading “Risk Factors” contained in this prospectus, any applicable prospectus supplement and any related free writing prospectus, and under similar headings in the other documents that are incorporated by reference into this prospectus. We have no shares

You should assume that the information appearing in this prospectus, any accompanying prospectus supplement or related free writing prospectus and any document incorporated herein by reference is accurate as of preferred stock outstandingits date only. Because the risk factors referred to above could cause actual results or outcomes to differ materially from those expressed in any forward-looking statements made by us or on our behalf, you should not place undue reliance on any forward-looking statements. Further, any forward-looking statement speaks only as of the date on which it is made. New factors emerge from time to time, and paid no dividendsit is not possible for us to predict which factors will arise. In addition, we cannot assess the impact of each factor on sharesour business or the extent to which any factor, or combination of preferred stock duringfactors, may cause actual results to differ materially from those contained in any forward-looking statements. Unless legally required, we do not undertake any obligation to release publicly any revisions to such forward-looking statements to reflect events or circumstances after the periods indicated. Therefore,date of this prospectus or to reflect the ratiosoccurrence of earnings to combined fixed charges and preferred dividends are the same as the ratios of earnings to fixed charges presented below.unanticipated events.

For purposes of calculating the ratios in the table above, earnings consist of net loss before income taxes. Fixed charges include interest expense on indebtedness and an estimate of the interest expense within rental expense.-7-

USE OF PROCEEDS

We intend to usewill not receive any of the net proceeds from the sale of our common stock by the selling stockholders named in this prospectus. All proceeds from the resale of the shares of our common stock offered by this prospectus will belong to the selling stockholders identified in this prospectus under “Selling Stockholders.”

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SELLING STOCKHOLDERS

This prospectus relates to the sale or other disposition of up to 12,860,272 shares of our common stock by the selling stockholders named below, and their donees, pledgees, transferees or othersuccessors-in-interest selling shares of common stock or interests in shares of common stock received after the date of this prospectus from a selling stockholder as a gift, pledge, partnership distribution or other transfer, collectively, the sellingstockholders. These shares consist of (i) 6,091,250 shares issued to certain of the selling stockholders pursuant to the Merger Agreement; (ii) 6,105,359 shares that were issued to certain of the selling stockholders in the Private Placement; (iii) 628,403 shares that are issuable upon exercise of thePre-Funded Warrants; and (iv) 35,260 shares that were issued as compensation to a placement agent for services rendered to Larimar in connection with the Private Placement. See “Prospectus Summary–The Merger, Reverse Stock Split and Name Change,” “Prospectus Summary–Private Placement of Common Stock andPre-Funded Warrants” and “Prospectus Summary-Description of Placement Agent Compensation.”

The table below sets forth information as of the date of this prospectus, to our knowledge, the selling stockholders and other information regarding the beneficial ownership (as determined under Section 13(d) of the Exchange Act and the rules and regulations thereunder) of the shares of common stock held by the selling stockholders. The second column lists the number of shares of common stock beneficially owned by the selling stockholders, as of June 26, 2020. The third column lists the maximum number of shares of common stock that may be sold or otherwise disposed of by the selling stockholders pursuant to the registration statement of which this prospectus forms a part. The selling stockholders may sell or otherwise dispose of some, all or none of their shares. Pursuant to Rules13d-3 and13d-5 of the Exchange Act, beneficial ownership includes any securitiesshares of our common stock as to which a stockholder has sole or shared voting power or investment power, and also any shares of our common stock which the stockholder has the right to acquire within 60 days of June 26, 2020. The percent of beneficial ownership for the selling stockholders is based on 15,356,206 shares of our common stock outstanding as of June 26, 2020 (which does not include the 628,403 shares of common stock issuable upon exercise of thePre-Funded Warrants). Except as described below, to our knowledge, none of the selling stockholders have been an officer or director of ours or of our affiliates within the past three years or had any material relationship with us or our affiliates within the past three years. Our knowledge is based on information provided by the selling stockholders in investor questionnaires in connection with the Merger and Private Placement, as well as information obtained from relevant Schedule 13D and 13G filings.

The shares of common stock being covered hereby may be sold or otherwise disposed of from time to time during the period the registration statement of which this prospectus is a part remains effective, by or for the account of the selling stockholders. After the date of effectiveness, the selling stockholders may have sold or transferred, in transactions covered by this prospectus or in transactions exempt from the registration requirements of the Securities Act, some or all of their common stock.

Information about the selling stockholders may change over time. Any changed information will be set forth in an amendment to the registration statement or supplement to this prospectus, to the extent required by law.

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PLAN OF DISTRIBUTION

The selling stockholders, which as used herein includes donees, pledgees, transferees or othersuccessors-in-interest selling shares of common stock or interests in shares of common stock received after the date of this prospectus from a selling stockholder as a gift, pledge, partnership distribution or other transfer, may, from time to time, sell, transfer or otherwise dispose of any or all of their shares of common stock or interests in shares of common stock on any stock exchange, market or trading facility on which the shares are traded or in private transactions. These dispositions may be at fixed prices, at prevailing market prices at the time of sale, at prices related to the prevailing market price, at varying prices determined at the time of sale, or at negotiated prices.

The selling stockholders may use any one or more of the following methods when disposing of shares or interests therein:

The selling stockholders may, from time to time, pledge or grant a security interest in some or all of the shares of common stock owned by them and, if they default in the performance of their secured obligations, the pledgees or secured parties may offer and sell the shares of common stock, from time to time, under this prospectus, or under an amendment or supplement 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 be the selling beneficial owners for general corporate purposes unless otherwise indicatedof 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 may in turn engage in short sales of the common stock in the applicablecourse of hedging the positions they assume. The selling stockholders may also sell shares of our common stock short and deliver these securities to close out their short positions, or loan or pledge the common stock to broker-dealers that in turn may sell these securities. The selling stockholders may also enter into option or other transactions with broker-dealers or other financial institutions or the creation of one or more derivative securities which require the delivery to such broker-dealer or other financial institution of shares offered by this prospectus, supplement. General corporate purposeswhich shares such broker-dealer or other financial institution may include research and development costs, potential strategic acquisitions of complementary businesses, servicesresell pursuant to this prospectus (supplemented or technologies, repayment and refinancing of debt, general and administrative costs, working capital and capital expenditures. We may temporarily invest the net proceeds in a variety of capital preservation instruments, including investment grade, interest bearing instruments and U.S. government securities, until they are used for their stated purpose. We have not determined the amount of netamended as necessary to reflect such transaction).

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The aggregate proceeds to be used specifically for such purposes. As a result, management will retain broad discretion over the allocation of net proceeds.

SECURITIES WE MAY OFFER

This prospectus contains summary descriptionsselling stockholders from the sale of the securities we may offercommon stock offered by them will be the purchase price of the 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. These summary descriptions are not meanttime, to reject, in whole or in part, any proposed purchase of common stock to be complete descriptionsmade directly or through agents. We will not receive any of each security. the proceeds from this offering. Upon any exercise of the Pre-Funded Warrants by payment of cash, however, we will receive the exercise price of the warrants.

The particular termsselling stockholders also may resell all or a portion of the shares in open market transactions in reliance upon Rule 144 under the Securities Act.

The selling stockholders and any underwriters, broker-dealers or agents that participate in the sale of the common stock or interests therein may be deemed to be “underwriters” within the meaning of Section 2(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.

To the extent required, the shares of our common stock to be sold, the names of the selling stockholders, the respective purchase prices and public offering prices, the names of any securityagents, dealer or underwriter, any applicable commissions or discounts with respect to a particular offer will be describedset forth in an accompanying prospectus supplement or, if appropriate, a post-effective amendment to the registration 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.

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 selling stockholders and their Affiliates. In addition, to the extent applicable we will make copies of this prospectus supplement.(as it may be supplemented or amended from time to time) available to the selling stockholders for the purpose of satisfying any prospectus delivery requirements of the Securities Act. The selling stockholders may indemnify any broker-dealer that participates in transactions involving the sale of the shares against certain liabilities, including liabilities arising under the Securities Act.

We have agreed to indemnify the selling stockholders against liabilities, including liabilities under the Securities Act and state securities laws, relating to the registration of the shares offered by this prospectus.

We have agreed with the selling stockholders to keep the registration statement of which this prospectus constitutes a part effective until the earlier of (1) such time as all of the shares covered by this prospectus have been disposed of pursuant to and in accordance with such registration statement or (2) the date on which all of the shares may be sold by the selling stockholders without restriction (including any current public information requirement) pursuant to Rule 144 of the Securities Act.

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DESCRIPTION OF CAPITAL STOCK

The following description of our common stock and preferred stock together with the additional information we include in any applicable prospectus supplements, summarizes the material terms and provisions of theour common stock and preferred stock that we may offer under this prospectus.stock. The following description of our capital stock does not purport to be complete and is subject to, and qualified in its entirety by, our ninth amended and restated certificate of incorporation, orreferred to in this section as the Charter, and our amended and restated bylaws, orby-laws, as may be amended, referred to in this section as the Bylaws, which are exhibitsincorporated by reference to Exhibits 3.1 and 3.2, respectively, of our Annual Report on Form10-K for the registration statement of which this prospectus forms a part,year ended December 31, 2019 as filed with the SEC on March 5, 2020 and by applicable law.law, and does not include changes resulting from the amendments to our Charter to effect a name change to Larimar Therapeutics, Inc. and to effect the Reverse Split (as defined below). The terms of our common stock and preferred stock may also be affected by Delaware law.

Common Stock

Authorized Capital Stock

. Our authorized capital stock consists of (i) 115,000,000 shares of common stock, par value $0.001 per share, of which 15,354,335 shares have been issued and are outstanding as of June 26, 2020, referred to as the capitalization date, and (ii) 5,000,000 shares of preferred stock, par value $0.001 per share. Asshare, of August 7, 2017, we had 27,483,925which no shares have been issued and are outstanding as of the capitalization date. We do not hold any shares of commonour capital stock outstanding and no shares of preferred stock outstanding.in its treasury.

Common Stock

Voting Rights. Holders of our common stock are entitled to one vote for each share held of record on all matters submitted to a vote of stockholders andstockholders. The holders of our common stock do not have any cumulative voting rights.

Dividends. Holders of our common stock are entitled to receive ratably any dividends declared by the boardour Board of directorsDirectors, or Board, out of funds legally available for that purpose, subject to any preferential dividend rights of any outstanding preferred stock.

No Preemptive or Similar Rights. Our common stock has no preemptive rights, conversion rights or other subscription rights or redemption or sinking fund provisions. In the event of oura liquidation, dissolution or winding up of us, holders of our common stock will be entitled to share ratably in all assets remaining after payment of all debts and other liabilities and any liquidation preference of any outstanding preferred stock. All outstanding shares are fully-paid andnon-assessable.

Listing

Our common stock is listed on The NASDAQ Global Market under the symbol “ZFGN.” On August 7, 2017, the closing price for our common stock, as reported on The NASDAQ Global Market, was $3.49 per share.

Transfer Agent and Registrar

. The transfer agent and registrar for our common stock is Computershare Trust Company, N.A.

Listing. Our common stock is listed on The Nasdaq Global Market under the symbol “LRMR.” On June 25, 2020, the last reported sale price of our common stock on The Nasdaq Global Market was $14.04 per share. As of June 26, 2020, we had approximately 55 stockholders of record.

Reverse Split

On May 28, 2020, we filed an amendment to our Charter in order to effect a1-for-12 reverse stock split of our common stock, or the Reverse Split, effective for trading purposes on May 29, 2020. The number of authorized stock remained unchanged at 120,000,000 shares.

Preferred Stock

Our board of directors is authorizedBoard currently has the authority, without further action by our stockholders, to issue up to 5,000,000 shares of preferred stock in one or more series without stockholder approval. Our board of directors may determineand to fix the rights, preferences, privileges and restrictions including votingthereof. These rights, preferences and privileges could include dividend rights, conversion rights, voting rights, terms of redemption, privileges and liquidation preferences, of each series of preferred stock.

The purpose of authorizing our board of directors to issue preferred stock in one or more seriessinking fund terms and determine the number of shares inconstituting, or the designation of, such series, and itsany or all of which may be greater than the rights and preferences is to eliminate delays associated with a stockholder vote on specific issuances. Examples of rights and preferences that the board of directors may fix are:

common stock. The existence of authorized but unissued sharesissuance of preferred stock may enable our board of directors to render more difficult or to discourage an attempt to obtain control ofby us by means of a merger, tender offer, proxy contest or otherwise. For example, if in the due exercise of its fiduciary obligations, our board of directors were to determine that a takeover proposal is not in the best interests of us or our stockholders, our board of directors could cause shares of preferred stock to be issued without stockholder approval in one or more private offerings or other transactions that might diluteadversely affect the voting or other rights of the proposed acquirer, stockholder or stockholder group. The rightspower of holders of our common stock described above,and the likelihood that such holders will be subject to,receive dividend payments and may be adversely affected by,payments upon a liquidation of us. In addition, the rights of any preferred stock that we may designate and issue in the future. The issuance of shares of preferred stock could decrease the amount of earnings and assets available for distribution to holders of shares of common stock. The issuance may also adversely affect the rights and powers, including voting rights, of these holders and may have the effect of delaying, deterringdeferring or preventing a change in control of us.

We will incorporate by reference as an exhibit to the registration statement, which includes this prospectus, the form of any certificate of designation that describes the terms of the series of preferred stock we are offering. This description and the applicable prospectus supplement will include:

When we issuecorporate action. No shares of preferred stock under this prospectus,are outstanding, and we have no present plans to issue any shares of preferred stock.

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Warrants

In connection with the Private Placement, we issued and soldpre-funded warrants to purchase 628,403 shares of our common stock, or thePre-Funded Warrants, to certain investors, or the Investors. ThePre-Funded Warrants are exercisable immediately upon issuance at an exercise price of $0.01 and will be exercisable indefinitely. The Investors may exercise thePre-Funded Warrants on a cashless basis in the event that there is no effective registration statement covering the resale of the shares of our common stock underlying thePre-Funded Warrants, or the Warrant Shares, on the date in which we are required to deliver the shares.

ThePre-Funded Warrants may not be exercised by the holder to the extent that the holder would beneficially own, after such exercise 9.99% of the shares of our common stock then outstanding (subject to the right of the holder to increase or decrease such beneficial ownership limitation upon notice to us, provided that such limitation cannot exceed 19.99%) and provided that any increase in the beneficial ownership limitation shall not be effective until 61 days after such notice is delivered.

Registration Rights

Shortly after the Merger we entered into a Registration Rights Agreement, or Merger Registration Rights Agreement, with the members of Chondrial Holdings, LLC pursuant to which we have agreed that promptly, but no later than 30 calendar days from the closing of the Merger, we will fully be paidfile a registration statement with the SEC covering the shares of common stock issued to Chondrial Holdings, LLC in exchange for all of the shares of common stock of Chondrial Therapeutics, Inc. and nonassessablesubsequently distributed to its members. We will use our commercially reasonable efforts to ensure that the such registration statement is declared effective as soon as practicable after the filing. In addition, the Merger Registration Rights Agreement also provides the members of Chondrial Holdings, LLC with demand and will not have, or be“piggy-back” registration rights, subject to any preemptivecertain minimum requirements and customary conditions.

In connection with the Private Placement, we entered into a Registration Rights Agreement, or similar rights.the Private Placement Registration Rights Agreement, and collectively with the Merger Registration Rights Agreement, the Registration Rights Agreements, with our investors pursuant to which we have agreed that promptly, but no later than 30 calendar days from the final closing of the Private Placement, we will file a registration statement with the SEC covering (a) the shares of common stock issued in the Offering and (b) the shares of common stock underlying thePre-Funded Warrants issued in the Private Placement. We will use our commercially reasonable efforts to ensure that such registration statement is declared effective as soon as practicable after the filing.

These registration rights granted under the Registration Rights Agreements are subject to certain conditions, including our right to delay or withdraw a registration statement under certain circumstances. The registration rights granted in the Registration Rights Agreements are also subject to customary indemnification and contribution provisions.

Provisions of ourOur Charter and Bylaws and Delaware Anti-Takeover Law

Certain provisions of the Delaware General Corporation Law, or DGCL, and of our Charter and Bylaws could have the effect of delaying, deferring or discouraging another party from acquiring control of us. These provisions, which are summarized below, are expected to discourage certain types of coercive takeover practices and inadequate takeover bids and, as a consequence, they might also inhibit temporary fluctuations in the market price of our common stock that often result from actual or rumored hostile takeover attempts. These provisions are also designed in part to encourage anyone seeking to acquire control of us or considering unsolicited tender offers or other unilateral takeover proposals to first negotiate with our board of directors rather than pursuenon-negotiated takeover attempts.Board. These provisions might also have the effect of preventing changes in our management. It is possible that these provisions could make it more difficult to accomplish transactions that stockholders might otherwise deem to be in their best interests. However, we believe that the advantages gained by protecting our ability to negotiate with any unsolicited and potentially unfriendly acquirer outweigh the disadvantages of discouraging such proposals, including those priced above the then-current market value of our common stock, because, among other reasons, the negotiation of such proposals could improve their terms.

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Board Composition and Filling Vacancies. Our Charter provides for the division of our board of directorsBoard into three classes serving staggered three-year terms, with one class being elected each year. Our Charter also provides that directors may be removed only for cause and then only by the affirmative vote of the holders of 75% or more of the shares then entitled to vote at an election of directors. Furthermore, any vacancy on our board of directors,Board, however occurring, including a vacancy resulting from an increase in the size of our board,Board, may only be filled by the affirmative vote of a majority of our directors then in office even if less than a quorum.

No Written Consent of Stockholders. Our Charter provides that all stockholder actions are required to be taken by a vote of the stockholders at an annual or special meeting, and that stockholders may not take any action by written consent in lieu of a meeting.

Meetings of Stockholders. Our Charter and Bylaws provide that only a majority of the members of our board of directorsBoard then in office may call special meetings of stockholders and only those matters set forth in the notice of the special meeting may be considered or acted upon at a special meeting of stockholders. Our Bylaws limit the business that may be conducted at an annual meeting of stockholders to those matters properly brought before the meeting.

Advance Notice Requirements.Requirements. Our Bylaws establish advance notice procedures with regard to stockholder proposals relating to the nomination of candidates for election as directors or new business to be brought before meetings of our stockholders. These procedures provide that notice of stockholder proposals must be timely given in writing to our corporate secretary prior to the meeting at which the action is to be taken. Generally, to be timely, notice must be received at our principal executive offices not less

than 90 days nor more than 120 days prior to the first anniversary date of the annual meeting for the preceding year. Our Bylaws specify the requirements as to form and content of all stockholders’ notices.

Amendment to Charter and Bylaws. As required by the Delaware General Corporation Law,DGCL, any amendment of our Charter must first be approved by a majority of our board of directors,Board, and if required by law or our Charter, must thereafter be approved by a majority of the outstanding shares entitled to vote on the amendment and a majority of the outstanding shares of each class entitled to vote thereon as a class, except that the amendment of the provisions relating to stockholder action, board composition, limitation of liability and the amendment of our Charter must be approved by not less than 75% of the outstanding shares entitled to vote on the amendment, and not less than 75% of the outstanding shares of each class entitled to vote thereon as a class. Our Bylaws may be amended by the affirmative vote of a majority of the directors then in office, subject to any limitations set forth in the Bylaws; and may also be amended by the affirmative vote of at least 75% of the outstanding shares entitled to vote on the amendment, or, if our board of directorsBoard recommends that the stockholders approve the amendment, by the affirmative vote of the majority of the outstanding shares entitled to vote on the amendment, in each case voting together as a single class.

As a Delaware Anti-Takeover Law

Wecorporation, we are also subject to the provisions of Delaware law, including Section 203 of the Delaware General Corporation Law.DGCL. In general, Section 203 prohibits a publicly-heldpublicly held Delaware corporation from engaging in a “business combination” with an “interested stockholder” for a three-year period following the time that this stockholder becomes an interested stockholder, unless the business combination is approved in a prescribed manner. A “business combination” includes, among other things, a merger, asset or stock sale or other transaction resulting in a financial benefit to the interested stockholder. An “interested stockholder” is a person who, together with affiliates and associates, owns, or did own within three years prior to the determination of interested stockholder status, 15% or more of the corporation’s voting stock. Under Section 203, a business combination between a corporation and an interested stockholder is prohibited unless it satisfies one of the following conditions:

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Exclusive JurisdictionSection 203 defines a business combination to include:

We also incorporate by reference any future filings we make(other than any filings or portions of such reports that are not deemed “filed” under the Exchange Act in accordance with the Exchange Act and applicable SEC rules, including current reports furnished under Item 2.02 or Item 7.01 of Form 8-K and exhibits furnished on such form that are related to such items unless such Form 8-K expressly provides to the contrary) made with the SEC underpursuant to Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act, including all filingsthose made after the date of the initial filing of thisthe registration statement of which this prospectus is a part and prior to the effectiveness of thisthe registration statement, except as to any portion of any future report or document that is not deemed filed under such provisions, until we sell allfile a post-effective amendment that indicates the termination of the securities:

Upon request, weWe will provide,furnish without charge to each person, including any beneficial owner, to whomyou, upon written or oral request, a copy of this prospectus is delivered, a copyany or all of the documents incorporated by reference, into this prospectus but not delivered with the prospectus. You may request a copy ofincluding exhibits to these filings, and any exhibits we have specifically incorporated by reference as an exhibit in this prospectus, at no costdocuments by writing or telephoning us at the following address:

Zafgen, Inc., 175 Portland Street, 4th Floor, Boston, MA 02114, Attention: Secretary,address or phone number below. You may also access this information on our website at www.larimartx.com by telephone requestviewing the “Financials & Filings” subsection of the “Investors” menu. No additional information is deemed to (617)622-4003.

This prospectus isbe part of a registration statement we filed with the SEC. We have incorporated exhibits into this registration statement. You should read the exhibits carefully for provisions that may be important to you.

You should rely only on the informationor incorporated by reference or provided ininto this prospectus or any prospectus supplement. We have not authorized anyone to provide you with different information. We are not making an offer of these securities in any state where the offer is not permitted. You should not assume that the information in this prospectus or in the documents incorporated by reference is accurate as of any date other than the date on the front of this prospectus or those documents.prospectus.

Attention: Corporate Secretary

Three Bala Plaza East, Suite 506

Bala Cynwyd, Pennsylvania, 19004

(484)414-2700

$150,000,000-22-

12,860,272 Shares

Common Stock

Preferred Stock

Debt Securities

Warrants

Units

PROSPECTUSProspectus

            , 2017

We have not authorized any dealer, salesperson or other person to give any information or represent anything not contained in this prospectus. You must not rely on any unauthorized information. If anyone provides you with different or inconsistent information, you should not rely on it. This prospectus does not offer to sell any securities in any jurisdiction where it is unlawful. Neither the delivery of this prospectus, nor any sale made hereunder, shall create any implication that the information in this prospectus is correct after the date hereof.2020

Part II—PART II

INFORMATION NOT REQUIRED IN THE PROSPECTUS

The following table sets forth an estimate of the fees and expenses payable by Zafgen, Inc. (the “Registrant” or the “Company”)us in connection with the issuance and distribution of the securitiesshares of common stock being registered (other than underwriting discounts and commissions, if any)by this registration statement. None of the expenses listed below are set forth below. Each item listed is estimated,to be borne by any of the selling stockholders named in the prospectus that forms a part of this registration statement. All the amounts shown are estimates, except for the Securities and Exchange Commission, (the “SEC”)or SEC, registration fee.

Section 145 ofWe are governed by the Delaware General Corporation Law, permitsor DGCL. Section 145 of the DGCL provides that a corporation may indemnify any person, including an officer or director, who was or is, or is threatened to be made, a party to any threatened, pending or completed legal action, suit or proceeding, whether civil, criminal, administrative or investigative (other than an action by or in the right of such corporation), by reason of the fact that such person was or is an officer, director, employee or agent of such corporation or is or was serving at the request of such corporation as a director, officer, employee or agent of another corporation or enterprise. The indemnity may include expenses (including attorneys’ fees), judgments, fines and amounts paid in its charter documents,settlement actually and reasonably incurred by such person in connection with such action, suit or proceeding, provided such officer, director, employee or agent acted in good faith and in agreements betweena manner such person reasonably believed to be in, or not opposed to, the corporation’s best interest and, for criminal proceedings, had no reasonable cause to believe that such person’s conduct was unlawful. A Delaware corporation may indemnify any person, including an officer or director, who was or is, or is threatened to be made, a party to any threatened, pending or contemplated action or suit by or in the right of such corporation, under the same conditions, except that such indemnification is limited to expenses (including attorneys’ fees) actually and reasonably incurred by such person, and except that no indemnification is permitted without judicial approval if such person is adjudged to be liable to such corporation. Where an officer or director of a corporation is successful, on the merits or otherwise, in the defense of any action, suit or proceeding referred to above, or any claim, issue or matter therein, the corporation must indemnify that person against the expenses (including attorneys’ fees) which such officer or director actually and its directors and officers, provisions expanding the scope of indemnification beyond that specifically provided by the current law.reasonably incurred in connection therewith.

Our Ninth Amended and Restated Certificate of Incorporation, as amended, or the Charter, provides for the indemnification of directors to the fullest extent permissible under Delaware law. Accordingly, our directors will not be personally liable for monetary damages for breach of their fiduciary duty as directors, except for liabilities:

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Our amended and restated bylaws, or the Bylaws, provide for the indemnification of officers, directors and third parties acting on our behalf if such persons act in good faith and in a manner reasonably believed to be in and not opposed to our best interest, and, with respect to any criminal action or proceeding, such indemnified party had no reason to believe his or her conduct was unlawful.

We have entered into indemnification agreements with each of our directors and certain of our executive officers. These agreements provide that we will indemnify each of our directors and certain of our executive officers to the fullest extent permitted by law. We intend to enter into indemnification agreements with any new directors and executive officers in the future.

We also maintain a general liability insurance policy which covers certain liabilities of directors and officers of our Company arising out of claims based on acts or omissions in their capacities as directors or officers.

We believe that the limitation of liability provision in the Charter and the indemnification agreements facilitate our ability to continue to attract and retain qualified individuals to serve as directors and officers. The limitation of liability and indemnification provisions in the Charter and Bylaws may discourage stockholders from bringing a lawsuit against directors for breach of their fiduciary duties. They may also reduce the likelihood of derivative litigation against directors and officers, even though an action, if successful, might benefit us and our stockholders. A stockholder’s investment may be harmed to the extent we pay the costs of settlement and damage awards against directors and officers pursuant to these indemnification provisions.

A list of exhibits filed with this registration statement onForm S-3 is set forth on the Exhibit Index and is incorporated herein by reference.

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(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 set forth in the registration statement. Notwithstanding the foregoing, any increase or decrease in the volume of securities offered (if the total dollar value of securities offered would not exceed that which was registered) and any deviation from the low or high end of the estimated maximum offering range may be reflected in the form of prospectus filed with the Securities and Exchange CommissionSEC pursuant to Rule 424(b) if, in the aggregate, the changes in volume and price represent no more than a 20 percent change in the maximum aggregate offering price set forth in the “Calculation of Registration Fee” table in the effective registration statement; and

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

provided,however, that paragraphs (a)(l)(1)(i), (a)(l)(1)(ii), and (a)(l)(1)(iii) of this sectionabove 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 Securities and Exchange CommissionSEC by the registrant pursuant to Sectionsection 13 or Sectionsection 15(d) of the Securities Exchange Act of 1934 that are incorporated by reference in the registration statement, or is contained in a form of prospectus filed pursuant to Rule 424(b) that is a part of the registration statement;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 initialbona fide offering thereof;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;offering.

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

(i)    If the registrant is relying on 430B:

(A)     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)(B)     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)(l)(1)(i), (vii), or (x) for the purpose of providing the information required by Sectionsection 10(a) of the Securities Act of 1933 shall be deemed to be part of and included in the registration statement as of the earlier of the date such form of prospectus is first used after effectiveness or the date of the first contract of sale of securities in the offering described in the prospectus. As provided in Rule 430B, for liability purposes of the issuer and any person that is at that date an underwriter, such date shall be deemed to be a new effective date of the registration statement relating to the securities in the registration statement to which that prospectus relates, and the offering of such securities at that time shall be deemed to be the initialbona fide offering thereof;thereof.provided, 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;date.

(5) That, for the purpose of determining liability of(ii)    If the registrant under the Securities Act of 1933is subject 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:

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(i) Any preliminaryRule 430C, each prospectus or prospectus of the undersigned registrant relating to the offering required to be filed pursuant to Rule 424;

(ii) Any free writing prospectus424(b) as part of a registration statement relating to an offering, other than registration statements relying on Rule 430B or other than prospectuses filed in reliance on Rule 430A, shall be deemed to be part of and included in the offering prepared by or on behalfregistration statement as of the date it is first used after effectiveness.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 first use, 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 date of first use.

(5)    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 communicationhereby undertakes that, is an offer in the offering made by the undersigned registrant to the purchaser;

(6) That, for purposes of determining any liability under the Securities Act of 1933, each filing of the registrant’s annual report pursuant to Section 13(a) or Section 15(d) of the Securities Exchange Act of 1934 (and, where applicable, each filing of an employee benefit plan’s annual report pursuant to Sectionsection 15(d) of the Securities Exchange Act of 1934) 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 initialbona fide offering thereof;thereof.

(7)(6)    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 CommissionSEC such indemnification is against public policy as expressed in the Securities Act of 1933 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 of 1933 and will be governed by the final adjudication of such issue;

(8) That, for purposes of determining any liability under the Securities Act of 1933, the information omitted from the form of prospectus filed as part of this registration statement in reliance upon Rule 430A and contained in a form of prospectus filed by the registrant pursuant to Rule 424(b)(1) or (4) or 497(h) under the Securities Act of 1933 shall be deemed to be part of this registration statement as of the time it was declared effective;

(9) That, for the purpose of determining any liability under the Securities Act of 1933, each post-effective amendment that contains a form of prospectus 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 initialbona fide offering thereof; and

(10) 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 of 1939 in accordance with the rules and regulations prescribed by the Securities and Exchange Commission under Section 305(b)(2) of the Trust Indenture Act of 1939.

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SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, the registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on FormS-3 and has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized, in Boston, Massachusetts,the Unincorporated Community of Bala Cynwyd, Commonwealth of Pennsylvania, on this 9th day of August, 2017.June 26, 2020.

POWER OF ATTORNEY

We, the undersigned officers and directors of Larimar Therapeutics, Inc., hereby severally constitutesconstitute and appoints each of Thomas E. Hughes, Ph.D.appoint CaroleBen-Maimon and Patricia L. Allen, and each of them singly, as such person’sMichael Celano, our true and lawfulattorneys-in-factattorney-in-fact and agents,agent, with full power of substitution and resubstitution in her or him for such personher or him and in such person’sher or his name, place and stead, and in any and all capacities, to sign any orand all amendments (including without limitation, post-effective amendments) to this registration statement, (or any registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933), and to file the same, with all exhibits thereto and allother documents in connection therewith, with the Securities and Exchange Commission, granting unto each saidattorney-in-fact and agent full power and authority to do and perform each and every act and thing requisite andor necessary to be done in and about the premises, as fullyfull to all intents and purposes as such personshe or he might or could do in person, hereby ratifying and confirming all that any saidattorney-in-fact and agent, or anyher or his substitute or substitutes, of any of them, may lawfully do or cause to be done by virtue hereof.

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

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EXHIBIT INDEX