EX-10.1





 Exhibit 10.1 

SECURITIES PURCHASE AGREEMENT 

This SECURITIES PURCHASE AGREEMENT (this “Agreement”) is made and entered into as of March 28, 2019 by and among Aileron
Therapeutics, Inc., a Delaware corporation (the “Company”), and the Investors identified on Exhibit A attached hereto (each an “Investor” and collectively the “Investors”). 

RECITALS 

A.    The Company and the Investors are executing and delivering this Agreement in reliance upon the exemption from
securities registration afforded by the provisions of Regulation D (“Regulation D”), as promulgated by the U.S. Securities and Exchange Commission (the “SEC”) under the Securities Act of 1933, as amended; and 

B.    The Investors wish to purchase from the Company, and the Company wishes to sell and issue to the Investors, upon the
terms and subject to the conditions stated in this Agreement, (i) (A) shares (the “Shares”) of the Company’s Common Stock, par value $0.001 per share (the “Common Stock”) and (B) warrants in the form attached
hereto as Exhibit B to purchase Common Stock (each, a “Common Warrant” and collectively, the “Common Warrants”) and/or (ii) (A) pre-funded warrants in the form attached hereto
as Exhibit C to purchase common stock (each, a “Pre-Funded Warrant” and collectively, the “Pre-Funded Warrants”) and (B) Common Warrants.

 C.    Contemporaneously with the sale of the Shares and Common Warrants, the parties hereto will execute and deliver
a Registration Rights Agreement, in the form attached hereto as Exhibit D (the “Registration Rights Agreement”), pursuant to which the Company will agree to provide certain registration rights in respect of the
Shares and the Common Warrant Shares (as defined below) under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder, and applicable state securities laws. 

In consideration of the mutual promises made herein and for other good and valuable consideration, the receipt and sufficiency of which are
hereby acknowledged, the parties hereto agree as follows: 
 1.    Definitions. For the purposes of this
Agreement, the following terms shall have the meanings set forth below: 
 “Affiliate” means, with respect to any Person,
any other Person which directly or indirectly through one or more intermediaries Controls, is controlled by, or is under common Control with, such Person. 

“Board” means the Company’s Board of Directors. 

“Business Day” means a day, other than a Saturday or Sunday, on which banks in New York City are open for the general
transaction of business. 
 “Closing” has the meaning set forth in Section 3.1. 












 “Closing Date” has the meaning set forth in Section 3.1. 

“Closing Securities” means the Shares and the Common Warrants. 

“Common Stock Equivalents” means any securities of the Company which would entitle the holder thereof to acquire at any time
Common Stock, including without limitation, any debt, preferred stock, rights, options, warrants or other instrument that is at any time convertible into or exchangeable for, or otherwise entitles the holder thereof to receive, Common Stock. 

“Common Warrants” has the meaning set forth in the recitals to this Agreement. 

“Common Warrant Shares” means the shares of Common Stock issuable upon exercise of the Common Warrants. 

“Company Intellectual Property” has the meaning set forth in Section 4.14. 

“Company’s Knowledge” means the actual knowledge of the executive officers (as defined in Rule 405 under the 1933
Act) of the Company. 
 “Control” (including the terms “controlling”, “controlled by” or “under
common control with”) means the possession, direct or indirect, of the power to direct or cause the direction of the management and policies of a Person, whether through the ownership of voting securities, by contract or otherwise. 

“Disclosure Schedules” has the meaning set forth in Section 4. 

“Disclosure Time” means, (i) if this Agreement is signed on a day that is not a Trading Day or after 9:00 a.m. (New York
City time) and before midnight (New York City time) on any Trading Day, 9:01 a.m. (New York City time) on the Trading Day immediately following the date hereof and (ii) if this Agreement is signed between midnight (New York City time) and 9:00
a.m. (New York City time) on any Trading Day, no later than 9:01 a.m. (New York City time) on the date hereof. 
 “Draft Form 10-K” means the draft of the Company’s Annual Report on Form 10-K for the year ended December 31, 2018 as provided to the Investors prior to the execution
of this Agreement. 
 “Environmental Laws” has the meaning set forth in Section 4.15. 

“Exempt Issuance” means the issuance of (a) Common Warrant Shares, (b) the
Pre-Funded Warrants Shares, (c) Common Stock or Common Stock Equivalents pursuant to any Company stock-based compensation plans approved by the Company’ stockholders or in accordance with Nasdaq
Stock Market Rule 5635(c)(4), (d) Common Stock upon the exercise or exchange of or conversion of any Common Stock Equivalents issued and outstanding on the date of this Agreement, (e) Common Stock or Common Stock Equivalents in connection with
a transaction with an unaffiliated third party approved by the Board that includes a bona fide commercial relationship with the Company (including any joint venture, marketing or distribution arrangement, strategic alliance, collaboration agreement
or corporate partnering, 

  
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intellectual property license agreement or acquisition agreement with the Company), (f) Common Stock or Common Stock Equivalents in connection with a merger with, or acquisition of, an
unaffiliated third party approved by the Board and (g) shares of Common Stock or Common Stock Equivalents issued to banks, equipment lessors or other financial institutions, or to real property lessors, pursuant to a debt financing, equipment
leasing or real property leasing transaction approved by the Board. 
 “FDA” has the meaning set forth in
Section 4.30. 
 “GAAP” has the meaning set forth in Section 4.17. 

“Losses” has the meaning set forth in Section 8.2. 

“Major Investor” means any Investor that, individually or together with such Investor’s Affiliates, has purchased
Securities with an aggregate purchase price of at least $5,000,000 under this Agreement. 
 “Material Adverse Effect” means
a material adverse effect on (i) the assets, liabilities, results of operations, financial condition or business of the Company, (ii) the legality or enforceability of any of the Transaction Documents or Closing Securities or
(iii) the ability of the Company to perform its obligations under the Transaction Documents. 
 “Material Contract”
means any contract, instrument or other agreement to which the Company is a party or by which it is bound that has been filed or was required to have been filed as an exhibit to the SEC Filings pursuant to Item 601(b)(4) or Item 601(b)(10) of Regulation S-K. 
 “Nasdaq” means The Nasdaq Global Market. 

“New Securities” means, collectively, equity securities of the Company, whether or not currently authorized, as well as
options or warrants to purchase such equity securities, or securities of any type whatsoever that are convertible or exchangeable into or exercisable for such equity securities. 

“Person” means an individual, corporation, partnership, limited liability company, trust, business trust, association, joint
stock company, joint venture, sole proprietorship, unincorporated organization, governmental authority or any other form of entity not specifically listed herein. 

“Placement Agent” means William Blair & Company, L.L.C. 

“Pre-Funded Warrants” has the meaning set forth in the recitals to this Agreement.

 “Pre-Funded Warrant Shares” means the shares of Common Stock issuable upon
exercise of the Pre-Funded Warrants. 
 “Press Release” has the meaning set forth
in Section 9.7. 

  
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 “Principal Trading Market” means the Trading Market on which the Common
Stock is primarily listed on and quoted for trading, which, as of the date of this Agreement and the Closing Date, shall be The Nasdaq Global Market. 

“Registration Rights Agreement” has the meaning set forth in the recitals to this Agreement. 

“Required Investors” has the meaning set forth in the Registration Rights Agreement. 

“Rule 144” means Rule 144 promulgated under the 1933 Act. 

“SEC Filings” means (i) all documents and reports filed by the Company with the SEC pursuant to the 1934 Act, including
pursuant to Section 13(a) or 15(d) thereof, since January 1, 2019 and (ii) the Draft Form 10-K. 

“Securities” means the Shares, the Common Warrants, the Pre-Funded Warrants and the
Warrant Shares. 
 “Shares” has the meaning set forth in the recitals to this Agreement. 

“Short Sales” means all “short sales” as defined in Rule 200 of Regulation SHO under the 1934 Act (but shall not be
deemed to include the location and/or reservation of borrowable shares of Common Stock). 
 “Subscription Amount” means, as
to an Investor, the aggregate amount to be paid for the Closing Securities purchased hereunder as specified opposite such Investor’s name on Exhibit A attached hereto, under the column entitled “Aggregate Purchase Price of Closing
Securities,” in U.S. Dollars and in immediately available funds. 
 “Trading Day” means (i) a day on which the
Common Stock is listed or quoted and traded on its Principal Trading Market (other than the OTC Bulletin Board), or (ii) if the Common Stock is not listed on a Trading Market (other than the OTC Bulletin Board), a day on which the Common Stock
is traded in the over-the-counter market, as reported by the OTC Bulletin Board, or (iii) if the Common Stock is not quoted on any Trading Market, a day on which
the Common Stock is quoted in the over-the-counter market as reported in the “pink sheets” by Pink Sheets LLC (or any similar organization or agency succeeding
to its functions of reporting prices); provided, that in the event that the Common Stock is not listed or quoted as set forth in (i), (ii) and (iii) hereof, then Trading Day shall mean a Business Day. 

“Trading Market” means whichever of the New York Stock Exchange, the NYSE American (formerly the American Stock Exchange),
the Nasdaq Global Select Market, the Nasdaq Global Market, the Nasdaq Capital Market or the OTC Bulletin Board on which the Common Stock is listed or quoted for trading on the date in question. 

“Transfer Agent” means Computershare Trust Company, N.A. 

“Transaction Documents” means this Agreement, the Common Warrants, the Pre-Funded
Warrants and the Registration Rights Agreement. 

  
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 “Warrants” means the Common Warrants and the
Pre-Funded Warrants. 
 “Warrant Shares” means the Common Warrant Shares and the Pre-Funded Warrant Shares. 
 “1933 Act” means the Securities Act of 1933, as amended, or
any successor statute, and the rules and regulations promulgated thereunder. 
 “1934 Act” means the Securities Exchange
Act of 1934, as amended, or any successor statute, and the rules and regulations promulgated thereunder. 

2.    Purchase and Sale. 

2.1.    On the Closing Date, upon the terms and subject to the conditions set forth herein, the Company will issue and
sell, and the Investors will purchase, severally and not jointly, (i) (A) the number of Shares set forth opposite the name of such Investor under the heading “Number of Shares to be Purchased” on Exhibit A attached hereto and
(B) a Common Warrant to purchase one share of Common Stock for every one Share purchased at Closing and (ii) the number of Pre-Funded Warrants set forth opposite the name of such Investor under the
heading “Number of Shares to be Purchased” on Exhibit A attached hereto, if any, and (ii) a Common Warrant to purchase one share of Common Stock for every one Pre-Funded Warrant purchased
at Closing. The purchase price per Share and associated Common Warrant shall be $2.01. The purchase price per Pre-Funded Warrant and associated Common Warrant shall be $2.01. 

2.2.    The Pre-Funded Warrants shall have an exercise price equal to $0.01 per Pre-Funded Warrant Share and shall be exercisable for one share of Common Stock (subject to adjustment as provided therein). The Common Warrants shall have an exercise price equal to $2.00 per Common Warrant Share
(subject to adjustment as provided therein). 
 3.    Closing. 

3.1.    Upon the satisfaction of the conditions set forth in Section 6, the completion of the
purchase and sale of the Closing Securities (the “Closing”) shall occur remotely via exchange of executed documents and funds on April 2, 2019 (the “Closing Date”). 

3.2.    On the Closing Date, each Investor shall deliver or cause to be delivered to the Company the Subscription Amount
via wire transfer of immediately available funds pursuant to the wire instructions delivered to such Investor by the Company on or prior to the Closing Date. 

3.3.    At or before the Closing, the Company shall deliver or cause to be delivered 

(a)    to each Investor purchasing Shares the following: 

(i)    a number of Shares, in the form of a certificate registered in the name of the Investor or via book entry to the
applicable account registered in the name of the 

  
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Investor at the Transfer Agent, as may be requested by the Investor, equal to the number of Shares set forth opposite the name of such Investor under the heading “Number of Shares to be
Purchased” on Exhibit A attached hereto; and 
 (ii)    a Common Warrant, registered in the name of such
Investor, to purchase up to the number of Common Warrant Shares set forth opposite the name of such Investor under the heading “Number of Common Warrant Shares Underlying Common Warrant Purchased” on Exhibit A attached hereto.

 (b)    to each Investor purchasing Pre-Funded Warrants the following: 

(i)    a Pre-Funded Warrant, registered in the name of such Investor, to purchase
up to the number of Pre-Funded Warrant Shares set forth opposite the name of such Investor under the heading “Number of Pre-Funded Warrant Shares Underlying Pre-Funded Warrant Purchased” on Exhibit A attached hereto; and 

(ii)    a Common Warrant, registered in the name of such Investor, to purchase up to the number of Common Warrant Shares
set forth opposite the name of such Investor under the heading “Number of Common Warrant Shares Underlying Common Warrant Purchased” on Exhibit A attached hereto. 

4.    Representations and Warranties of the Company. The Company hereby represents and warrants to the Investors
that, except (a) as set forth in the schedules delivered herewith (collectively, the “Disclosure Schedules”) and arranged in numbered and lettered sections corresponding to the numbered and lettered sections contained in this
Section 4 or (b) or disclosed in the SEC Filings (excluding exhibits and information incorporated therein): 

4.1.    Organization, Good Standing and Qualification. The Company is a corporation duly organized, validly existing
and in good standing under the laws of the jurisdiction of its incorporation and has all requisite corporate power and authority to carry on its business as now conducted and to own or lease its properties. The Company is duly qualified to do
business as a foreign corporation and is in good standing in each jurisdiction in which the conduct of its business or its ownership or leasing of property makes such qualification or leasing necessary unless the failure to so qualify has not had
and would not reasonably be expected to have a Material Adverse Effect. 
 4.2.    Authorization. The Company has
the requisite corporate power and authority and has taken all requisite corporate action necessary for, and no further action on the part of the Company, its officers, directors and stockholders is necessary for, (i) the authorization,
execution and delivery of the Transaction Documents, (ii) the authorization of the performance of all obligations of the Company hereunder or thereunder, and (iii) the authorization, issuance (or reservation for issuance) and delivery of
the Closing Securities. The Transaction Documents constitute the legal, valid and binding obligations of the Company, enforceable against the Company in accordance with their terms, subject to bankruptcy, insolvency, fraudulent transfer,
reorganization, moratorium and similar laws of general applicability, relating to or affecting creditors’ rights generally and to general equitable principles. 

  
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 4.3.    Capitalization. The Company is authorized under its
Certificate of Incorporation to issue 150,000,000 shares of Common Stock. The Company’s disclosure of its issued and outstanding capital stock in its most recent SEC Filing containing such disclosure was accurate in all material respects as of
the date indicated in such SEC Filing. All of the issued and outstanding shares of the Company’s capital stock have been duly authorized and validly issued and are fully paid and nonassessable; none of such shares were issued in violation of
any pre-emptive rights; and such shares were issued in compliance in all material respects with applicable state and federal securities law and any rights of third parties. No Person is entitled to pre-emptive or similar statutory or contractual rights with respect to the issuance by the Company of any securities of the Company. There are no outstanding warrants, options, convertible securities or other
rights, agreements or arrangements of any character under which the Company is or may be obligated to issue any equity securities of any kind and except as contemplated by this Agreement. Except for the Registration Rights Agreement, there are no
voting agreements, buy-sell agreements, option or right of first purchase agreements or other agreements of any kind among the Company and any of the securityholders of the Company relating to the securities
of the Company held by them. Except as provided in the Registration Rights Agreement, no Person has the right to require the Company to register any securities of the Company under the 1933 Act, whether on a demand basis or in connection with the
registration of securities of the Company for its own account or for the account of any other Person. 
 The issuance and sale of the
Closing Securities hereunder will not obligate the Company to issue shares of Common Stock or other securities to any other Person (other than the Investors) and will not result in the adjustment of the exercise, conversion, exchange or reset price
of any outstanding security. 
 The Company does not have outstanding stockholder purchase rights or “poison pill” or any similar
arrangement in effect giving any Person the right to purchase any equity interest in the Company upon the occurrence of certain events. 

4.4.    Valid Issuance. The Shares have been duly and validly authorized and, when issued and paid for pursuant to
this Agreement, will be validly issued, fully paid and nonassessable, and shall be free and clear of all encumbrances and restrictions (other than those created by the Investors), except for restrictions on transfer set forth in the Transaction
Documents or imposed by applicable securities laws. The Common Warrant Shares have been duly and validly authorized and reserved for issuance and, upon exercise of the Common Warrants in accordance with their terms, including the payment of any
exercise price therefor, will be validly issued, fully paid and nonassessable and will be free and clear of all encumbrances and restrictions (other than those created by the Investors), except for restrictions on transfer set forth in the
Transaction Documents or imposed by applicable securities laws. The Pre-Funded Warrant Shares have been duly and validly authorized and reserved for issuance and, upon exercise of the Pre-Funded Warrants in accordance with their terms, including the payment of any exercise price therefor, will be validly issued, fully paid and nonassessable and will be free and clear of all encumbrances and
restrictions (other than those created by the Investors), except for restrictions on transfer set forth in the Transaction Documents or imposed by applicable securities laws. 

  
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 4.5.    Consents. Subject to the accuracy of the representations
and warranties of each Investor set forth in Section 5 hereof, the execution, delivery and performance by the Company of the Transaction Documents and the offer, issuance and sale of the Closing Securities require no consent of, action by or in
respect of, or filing with, any Person, governmental body, agency, or official other than filings that have been made pursuant to applicable state securities laws and post-sale filings pursuant to applicable state and federal securities laws and the
rules and regulations of Nasdaq which the Company undertakes to file within the applicable time periods and other than the registration statement required to be filed by the Registration Rights Agreement. The Company has taken all action necessary
to exempt (i) the issuance and sale of the Closing Securities and (ii) the other transactions contemplated by the Transaction Documents from the provisions of any stockholder rights plan or other “poison pill” arrangement, any
anti-takeover, business combination or control share law or statute binding on the Company, including Section 203 of the General Corporation Law of the State of Delaware, or to which the Company or any of its assets and properties is subject
that is or could reasonably be expected to become applicable to the Investors as a result of the transactions contemplated hereby, including without limitation, the issuance of the Closing Securities and the acquisition, ownership, disposition or
voting of the Shares or the Warrant Shares by the Investors or the exercise of any right granted to the Investors pursuant to this Agreement or the other Transaction Documents. 

4.6.    Use of Proceeds. The net proceeds of the sale of the Closing Securities hereunder shall be used by the
Company for working capital and general corporate purposes. 
 4.7.    No Material Adverse Change. Since
December 31, 2018, except as identified and described in the SEC Filings, there has not been: 
 (i)    any change
in the assets, liabilities, financial condition or operating results of the Company from that reflected in the financial statements included in the Draft Form 10-K as provided to Investors prior to execution
of this Agreement, except for changes in the ordinary course of business which have not had and would not reasonably be expected to have a Material Adverse Effect, individually or in the aggregate; 

(ii)    any declaration or payment by the Company of any dividend, or any authorization or payment by the Company of any
distribution, on any of the capital stock of the Company, or any redemption or repurchase by the Company of any securities of the Company; 

(iii)    any material damage, destruction or loss, whether or not covered by insurance, to any assets or properties of
the Company; 
 (iv)    any waiver, not in the ordinary course of business, by the Company of a material right or of a
material debt owed to it; 
 (v)    any satisfaction or discharge of any lien, claim or encumbrance or payment of any
obligation by the Company, except in the ordinary course of business and which is not material to the assets, properties, financial condition, operating results or business of the Company (as such business is presently conducted); 

  
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 (vi)    any change or amendment to the Company’s Certificate of
Incorporation or Bylaws, or material change to any material contract or arrangement by which the Company or is bound or to which any of its assets or properties is subject; 

(vii)    any material labor difficulties or, to the Company’s Knowledge, labor union organizing activities with
respect to employees of the Company; 
 (viii)    any material transaction entered into by the Company other than in
the ordinary course of business; 
 (ix)    the loss of the services of any key employee, or material change in the
composition or duties of the senior management of the Company; 
 (x)    any transaction disclosable under Item 404 of
Regulation S-K; 
 (xi)    the loss or, to the Company’s Knowledge,
threatened loss of any customer which has had or would reasonably be expected to have a Material Adverse Effect; or 

(xii)    any other event or condition of any character that has had or would reasonably be expected to have a Material
Adverse Effect. 
 4.8.    SEC Filings. 

(a)    The Company has filed all reports, schedules, certifications, forms, statements and other documents (including all
exhibits, amended and supplements thereto) required to be filed or furnished by the Company under the 1934 Act, including pursuant to Section 13(a) or 15(d) thereof, for the one year preceding the date hereof. As of their respective dates, or,
if amended or supplemented, as of the date of the last such amendment or supplement filed prior to date hereof, each of the SEC Filings complied in all material respects with the applicable requirements of the 1933 Act, the 1934 Act and the
Sarbanes-Oxley Act of 2002, and the applicable rules and regulations promulgated thereunder, as the case may be, each as in effect on the date so filed. 

4.9.    No Conflict, Breach, Violation or Default. The execution, delivery and performance of the Transaction
Documents by the Company and the issuance and sale of the Closing Securities in accordance with the provisions thereof will not, (i) conflict with or result in a breach or violation of (a) any of the terms and provisions of, or constitute
a default under, the Company’s Certificate of Incorporation or the Company’s Bylaws, both as in effect on the date hereof (true and complete copies of which have been made available to the Investors through the Electronic Data Gathering,
Analysis, and Retrieval system (the “EDGAR system”)), or (b) assuming the accuracy of the representations and warranties in Section 5, any applicable statute, rule, regulation or order of any governmental agency or body or any
court, domestic or foreign, having jurisdiction over the Company or any of its assets or properties, or (ii) except for such violations, conflicts or defaults as would not reasonably be expected, individually or in the aggregate, to have a
Material Adverse Effect, conflict with, or constitute a default (or an event that with notice or lapse of time or both would become a default) under, result in the creation of any lien, encumbrance or other adverse claim upon any of the properties
or assets of the Company or give to others any rights of termination, amendment, acceleration or cancellation 

  
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(with or without notice, lapse of time or both) of, any Material Contract. This Section does not relate to matters with respect to tax status, which are the subject of Section 4.10, employee
relations and labor matters, which are the subject of Section 4.13, and environmental laws, which are the subject of Section 4.15. 

4.10.    Tax Matters. The Company has timely prepared and filed all tax returns required to have been filed by it
with all appropriate governmental agencies and timely paid all taxes shown thereon or otherwise owed by the Company. The charges, accruals and reserves on the books of the Company in respect of taxes for all fiscal periods are adequate in all
material respects, and there are no material unpaid assessments against the Company nor, to the Company’s Knowledge, any basis for the assessment of any additional taxes, penalties or interest for any fiscal period or audits by any federal,
state or local taxing authority except for any assessment which is not material to the Company. All taxes and other assessments and levies that the Company is required to withhold or to collect for payment have been duly withheld and collected and
paid to the proper governmental entity or third party when due. There are no tax liens or claims pending or, to the Company’s Knowledge, threatened against the Company or any of its assets or property. There are no outstanding tax sharing
agreements or other such arrangements between the Company and any other corporation or entity. 
 4.11.    Title to
Properties. The Company has good and marketable title to all real properties and all other properties and assets owned by it, in each case free from liens, encumbrances and defects, except such as would not reasonably be expected, individually
or in the aggregate, to have a Material Adverse Effect; and the Company holds any leased real or personal property under valid and enforceable leases with no exceptions, except such as would not reasonably be expected, individually or in the
aggregate, to have a Material Adverse Effect. 
 4.12.    Certificates, Authorities and Permits. The Company
possesses adequate certificates, authorities or permits issued by appropriate governmental agencies or bodies necessary to conduct the business now operated by it, except where failure to so possess would not reasonably be expected, individually or
in the aggregate, to result in a Material Adverse Effect. The Company has not received any written notice of proceedings relating to the revocation or modification of any such certificate, authority or permit that would reasonably be expected to
have a Material Adverse Effect, individually or in the aggregate, on the Company. 
 4.13.    Labor Matters. 

(a)    The Company is not party to or bound by any collective bargaining agreements or other agreements with labor
organizations. To the Company’s knowledge, Company has not violated in any material respect any laws, regulations, orders or contract terms, affecting the collective bargaining rights of employees, labor organizations or any laws, regulations
or orders affecting employment discrimination, equal opportunity employment, or employees’ health, safety, welfare, wages and hours. 

(b)    No material labor dispute with the employees of the Company, or with the employees of any principal supplier,
manufacturer, customer or contractor of the Company, exists or, to the knowledge of the Company, is threatened or imminent. 

  
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 4.14.    Intellectual Property. Except as expressly contemplated
by the SEC Filings, the Company owns, possesses, licenses or has other rights to use, the patents and patent applications, copyrights, trademarks, service marks, trade names, service names and trade secrets described in the SEC Filings as necessary
or material for use in connection with its business and which the failure to so have would have or reasonably be expected to result in a Material Adverse Effect (collectively, the “Company Intellectual Property”). There is no pending or,
to the Company’s Knowledge, threatened action, suit, proceeding or claim by any Person that the Company’s business as now conducted infringes or otherwise violates any patent, trademark, copyright, trade secret or other proprietary rights
of another. To the Company’s Knowledge, there is no existing infringement by another Person of any of the Intellectual Property Rights that would have or would reasonably be expected to have a Material Adverse Effect. The Company has taken
reasonable security measures to protect the secrecy, confidentiality and value of all of its Intellectual Property Rights, except where failure to do so would not, individually or in the aggregate, reasonably be expected to have a Material Adverse
Effect. 
 4.15.    Environmental Matters. The Company is not in violation of any statute, rule, regulation,
decision or order of any governmental agency or body or any court, domestic or foreign, relating to the use, disposal or release of hazardous or toxic substances or relating to the protection or restoration of the environment or human exposure to
hazardous or toxic substances (collectively, “Environmental Laws”), has not released any hazardous substances regulated by Environmental Law on to any real property that it owns or operates, has not received any written notice or claim it
is liable for any off-site disposal or contamination pursuant to any Environmental Laws, which violation, release, notice, claim, or liability would reasonably be expected, individually or in the aggregate, to
have a Material Adverse Effect,; and to the Company’s Knowledge, there is no pending or threatened investigation that would reasonably be expected to lead to such a claim. 

4.16.    Legal Proceedings. There are no legal, governmental or regulatory investigations, actions, suits or
proceedings pending to which the Company is or may reasonably be expected to become a party or to which any property of the Company is or may reasonably be expected to become the subject that, individually or in the aggregate, would reasonably be
expected to have a Material Adverse Effect. 
 4.17.    Financial Statements. The financial statements included
in each SEC Filing filed prior to the date hereof comply in all material respects with applicable accounting requirements and the rules and regulations of the SEC with respect thereto as in effect at the time of filing and present fairly, in all
material respects, the financial position of the Company as of the dates shown and its results of operations and cash flows for the periods shown, subject in the case of unaudited financial statements to normal, immaterial year-end audit adjustments, and such financial statements have been prepared in conformity with United States generally accepted accounting principles applied on a consistent basis during the periods involved
(“GAAP”) (except as may be disclosed therein or in the notes thereto, and except that the unaudited financial statements may not contain all footnotes required by GAAP, and, in the case of quarterly financial statements, as permitted by
Form 10-Q under the 1934 Act). Except as set forth in the financial statements of the Company included in the SEC Filings filed prior to the date hereof, the Company has not incurred any liabilities,
contingent or otherwise, except those incurred in the ordinary course of business, consistent (as to amount and nature) with past practices since the date of such financial statements, none of which, individually or in the aggregate, have had or
would reasonably be expected to have a Material Adverse Effect. 

  
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 4.18.    Insurance Coverage. The Company maintains in full force
and effect insurance coverage that is customary for comparably situated companies for the business being conducted and properties owned or leased by the Company, and the Company reasonably believes such insurance coverage to be adequate against all
liabilities, claims and risks against which it is customary for comparably situated companies to insure. 

4.19.    Compliance with Nasdaq Continued Listing Requirements. The Company is in compliance with applicable Nasdaq
continued listing requirements and the execution, delivery and performance by the Company of the Transaction Documents and the offer, issuance and delivery of the Closing Securities will not violate applicable Nasdaq continued listing requirements.
There are no proceedings pending or, to the Company’s Knowledge, threatened against the Company relating to the continued listing of the Common Stock on Nasdaq and the Company has not received any notice of, nor to the Company’s Knowledge
is there any reasonable basis for, the delisting of the Common Stock from Nasdaq. 
 4.20.    Brokers and
Finders. Other than the Placement Agent, no Person will have, as a result of the transactions contemplated by the Transaction Documents, any valid right, interest or claim against or upon the Company or an Investor for any commission, fee or
other compensation pursuant to any agreement, arrangement or understanding entered into by or on behalf of the Company. No Investor shall have any obligation with respect to any fees, or with respect to any claims made by or on behalf of other
Persons for fees, in each case of the type contemplated by this Section 4.20 that may be due in connection with the transactions contemplated by this Agreement or the Transaction Documents. 

4.21.    No Directed Selling Efforts or General Solicitation. Neither the Company nor any Person acting on its
behalf has conducted any general solicitation or general advertising (as those terms are used in Regulation D) in connection with the offer or sale of any of the Closing Securities. 

4.22.    No Integrated Offering. Neither the Company nor any Person acting on its behalf has, directly or
indirectly, made any offers or sales of any Company security or solicited any offers to buy any Company security, under circumstances that would adversely affect reliance by the Company on Section 4(2) for the exemption from registration for
the transactions contemplated hereby or would require registration of the Closing Securities under the 1933 Act. 

4.23.    Private Placement. Assuming the accuracy of the representations and warranties of the Investors set forth
in Section 5, the offer and sale of the Closing Securities to the Investors as contemplated hereby is exempt from the registration requirements of the 1933 Act. The issuance and sale of the Closing Securities does not contravene the rules and
regulations of Nasdaq. 
 4.24.    Questionable Payments. Neither the Company nor, to the
Company’s Knowledge, any of its current or former directors, officers, employees, agents or other Persons acting on behalf of the Company, has on behalf of the Company in connection with its business:


  
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(a) used any corporate funds for unlawful contributions, gifts, entertainment or other unlawful expenses relating to political activity; (b) made any direct or indirect unlawful
payments to any governmental officials or employees from corporate funds; (c) established or maintained any unlawful or unrecorded fund of corporate monies or other assets which is in violation of law; (d) made any false or fictitious
entries on the books and records of the Company; or (e) made any unlawful bribe, rebate, payoff, influence payment, kickback or other unlawful payment of any nature. 

4.25.    Transactions with Affiliates. None of the executive officers or directors of the Company and, to the
Company’s Knowledge, none of the employees of the Company is presently a party to any transaction with the Company (other than as holders of stock options and/or warrants, and for services as employees, officers and directors), including any
contract, agreement or other arrangement providing for the furnishing of services to or by, providing for rental of real or personal property to or from, or otherwise requiring payments to or from any officer, director or such employee or, to the
Company’s Knowledge, any entity in which any officer, director, or any such employee has a substantial interest or is an officer, director, trustee or partner. 

4.26.    Internal Controls. The Company has established and maintains disclosure controls and procedures (as
defined in Rules 13a-15 and 15d-15 under the 1934 Act), which are designed to ensure that material information relating to the Company is made known to the
Company’s principal executive officer and its principal financial officer by others within those entities. Since the end of the Company’s most recent audited fiscal year, there have been no significant deficiencies or material weakness in
the Company’s internal control over financial reporting (whether or not remediated) and no change in the Company’s internal control over financial reporting that has materially affected, or is reasonably likely to materially affect, the
Company’s internal control over financial reporting. The Company is not aware of any change in its internal controls over financial reporting that has occurred during its most recent fiscal quarter that has materially affected, or is reasonably
likely to materially affect, the Company’s internal control over financial reporting. 

4.27.    Disclosures. Neither the Company nor any Person acting on its behalf has provided the Investors or their
agents or counsel with any information that constitutes or would reasonably be expected to constitute material, non-public information which according to applicable law, rule or regulation was required to have
been disclosed publicly by the Company, but which has not been so disclosed, other than with respect to the transactions contemplated hereby and except as will be disclosed in the Press Release (as defined below). The SEC Filings do not contain any
untrue statement of a material fact or omit to state a material fact necessary in order to make the statements contained therein, in light of the circumstances under which they were made, not misleading. The Company understands and confirms that the
Investors will rely on the foregoing representations in effecting transactions in securities of the Company.

4.28.    Required Filings. Since December 31, 2018, no event or circumstance has occurred or information
exists with respect to the Company or its business, properties, operations or financial condition, which, under applicable law, rule or regulation, requires public disclosure or announcement by the Company but which have not been so publicly
announced or disclosed (assuming for this purpose that the SEC Filings are being incorporated by reference into an effective registration statement filed by the Company under the 1933 Act). 

  
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 4.29.    Investment Company. The Company is not required to be
registered as, and is not an Affiliate of, and immediately following the Closing will not be required to register as, an “investment company” within the meaning of the Investment Company Act of 1940, as amended. 

4.30.    Tests and Preclinical and Clinical Trials. The studies, tests and preclinical and clinical trials
conducted by or, to the Company’s Knowledge, on behalf of the Company that are described in the SEC Filings were and, if still pending, are being, conducted in all material respects in accordance with the protocols submitted to the U.S. Food
and Drug Administration (the “FDA”) or any foreign governmental body exercising comparable authority, procedures and controls pursuant to, where applicable, accepted professional and scientific standards, and all applicable laws and
regulations; the descriptions of the studies, tests and preclinical and clinical trials conducted by or, to the Company’s Knowledge, on behalf of the Company, and the results thereof, contained in the SEC Filings are accurate and complete in
all material respects; the Company is not aware of any other studies, tests or preclinical and clinical trials, the results of which call into question the results described in the SEC Filings; and the Company has not received any notices or
correspondence from the FDA, any foreign, state or local governmental body exercising comparable authority or any Institutional Review Board requiring the termination, suspension, material modification or clinical hold of any studies, tests or
preclinical or clinical trials conducted by or on behalf of the Company. 
 4.31.    Manipulation of
Price. The Company has not, and, to the Company’s Knowledge, no Person acting on its behalf has taken, directly or indirectly, any action designed to cause or to result in the stabilization or manipulation of the price of any security
of the Company to facilitate the sale or resale of any of the Securities. 
 4.32.    Anti-Bribery and Anti-Money
Laundering Laws. Each of the Company and any of its officers, directors, supervisors, managers, agents, or employees, are and have at all times been in compliance with and its participation in the offering will not violate: (A) anti-bribery
laws, including but not limited to, any applicable law, rule, or regulation of any locality, including but not limited to any law, rule, or regulation promulgated to implement the OECD Convention on Combating Bribery of Foreign Public Officials in
International Business Transactions, signed December 17, 1997, including the U.S. Foreign Corrupt Practices Act of 1977, as amended, the U.K. Bribery Act 2010, or any other law, rule or regulation of similar purposes and scope or
(B) anti-money laundering laws, including but not limited to, applicable federal, state, international, foreign or other laws, regulations or government guidance regarding anti-money laundering, including, without limitation, Title 18 US. Code
section 1956 and 1957, the Patriot Act, the Bank Secrecy Act, and international anti-money laundering principles or procedures by an intergovernmental group or organization, such as the Financial Action Task Force on Money Laundering, of which the
United States is a member and with which designation the United States representative to the group or organization continues to concur, all as amended, and any Executive order, directive, or regulation pursuant to the authority of any of the
foregoing, or any orders or licenses issued thereunder. 

  
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 4.33.    Shell Company Status. The Company is not, and has never
been, an issuer identified in, or subject to, Rule 144(i). 
 5.    Representations and Warranties of the
Investors. Each of the Investors hereby severally, and not jointly, represents and warrants to the Company that: 

5.1.    Organization and Existence. Such Investor is a validly existing corporation, limited partnership or limited
liability company and has all requisite corporate, partnership or limited liability company power and authority to enter into and consummate the transactions contemplated by the Transaction Documents and to carry out its obligations hereunder and
thereunder, and to invest in the Securities pursuant to this Agreement. 
 5.2.    Authorization. The execution,
delivery and performance by such Investor of the Transaction Documents to which such Investor is a party have been duly authorized and each has been duly executed and when delivered will constitute the valid and legally binding obligation of such
Investor, enforceable against such Investor in accordance with their respective terms, subject to bankruptcy, insolvency, fraudulent transfer, reorganization, moratorium and similar laws of general applicability, relating to or affecting
creditors’ rights generally. 
 5.3.    Purchase Entirely for Own Account. The Securities to be received by
such Investor hereunder will be acquired for such Investor’s own account, not as nominee or agent, and not with a view to the resale or distribution of any part thereof in violation of the 1933 Act, and such Investor has no present intention of
selling, granting any participation in, or otherwise distributing the same in violation of the 1933 Act without prejudice, however, to such Investor’s right at all times to sell or otherwise dispose of all or any part of such Securities in
compliance with applicable federal and state securities laws. Nothing contained herein shall be deemed a representation or warranty by such Investor to hold the Securities for any period of time. Such Investor is not a broker-dealer
registered with the SEC under the 1934 Act or an entity engaged in a business that would require it to be so registered. 

5.4.    Investment Experience. Such Investor acknowledges that it can bear the economic risk and complete loss of
its investment in the Securities and has such knowledge and experience in financial or business matters that it is capable of evaluating the merits and risks of the investment contemplated hereby. 

5.5.    Disclosure of Information. Such Investor has had an opportunity to receive, review and understand all
information related to the Company requested by it and to ask questions of and receive answers from the Company regarding the Company, its business and the terms and conditions of the offering of the Securities, and has conducted and completed its
own independent due diligence. Such Investor acknowledges that copies of the SEC Filings are available on the EDGAR system. Based on the information such Investor has deemed appropriate, and without reliance upon any Placement Agent, it has
independently made its own analysis and decision to enter into the Transaction Documents. Such Investor is relying exclusively on its own sources of information, investment analysis and due diligence (including professional advice it deems
appropriate) with respect to the execution, delivery and performance of the Transaction Documents, the Securities and the business, condition (financial and otherwise), management, operations, properties and prospects of the Company, including but


  
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not limited to all business, legal, regulatory, accounting, credit and tax matters. Neither such inquiries nor any other due diligence investigation conducted by such Investor shall modify, limit
or otherwise affect such Investor’s right to rely on the Company’s representations and warranties contained in this Agreement. 

5.6.    Restricted Securities. Such Investor understands that the Securities are characterized as “restricted
securities” under the U.S. federal securities laws inasmuch as they are being acquired from the Company in a transaction not involving a public offering and that under such laws and applicable regulations such securities may be resold without
registration under the 1933 Act only in certain limited circumstances. 
 5.7.    Accredited Investor. Such
Investor is (a) an “accredited investor” within the meaning of Rule 501 under the 1933 Act and has executed and delivered to the Company a questionnaire in substantially the form attached hereto as Exhibit E (the “Investor
Questionnaire”), which such Investor represents and warrants is true, correct and complete. Such investor has sufficient knowledge and experience in investing in private equity transactions to properly evaluate the risks and merits of its
purchase of the Securities. Such Investor has determined based on its own independent review and such professional advice as it deems appropriate that its purchase of the Securities and participation in the transactions contemplated by the
Transaction Documents (i) are fully consistent with its financial needs, objectives and condition, (ii) comply and are fully consistent with all investment policies, guidelines and other restrictions applicable to such Investor,
(iii) have been duly authorized and approved by all necessary action, (iv) do not and will not violate or constitute a default under such Investor’s charter, bylaws or other constituent document or under any law, rule, regulation,
agreement or other obligation by which such Investor is bound and (v) are a fit, proper and suitable investment for such Investor, notwithstanding the substantial risks inherent in investing in or holding the Securities. 

5.8.    Placement Agent. Such Investor hereby acknowledges and agrees that (a) the Placement Agent is acting
solely as placement agent in connection with the execution, delivery and performance of the Transaction Documents and is not acting as an underwriter or in any other capacity and is not and shall not be construed as a fiduciary for such Investor,
the Company or any other person or entity in connection with the execution, delivery and performance of the Transaction Documents, (b) the Placement Agent has not made and will not make any representation or warranty, whether express or
implied, of any kind or character and has not provided any advice or recommendation in connection with the execution, delivery and performance of the Transaction Documents, (c) the Placement Agent will not have any responsibility with respect
to (i) any representations, warranties or agreements made by any person or entity under or in connection with the execution, delivery and performance of the Transaction Documents, or the execution, legality, validity or enforceability (with
respect to any person) thereof, or (ii) the business, affairs, financial condition, operations, properties or prospects of, or any other matter concerning the Company, and (d) the Placement Agent will not have any liability or obligation
(including without limitation, for or with respect to any losses, claims, damages, obligations, penalties, judgments, awards, liabilities, costs, expenses or disbursements incurred by such Investor, the Company or any other person or entity),
whether in contract, tort or otherwise, to such Investor, or to any person claiming through it, in respect of the execution, delivery and performance of the Transaction Documents. 

  
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 5.9.    No General Solicitation. Such Investor did not learn of
the investment in the Securities as a result of any general solicitation or general advertising. 
 5.10.    Brokers
and Finders. No Person will have, as a result of the transactions contemplated by the Transaction Documents, any valid right, interest or claim against or upon the Company or an Investor for any commission, fee or other compensation pursuant to
any agreement, arrangement or understanding entered into by or on behalf of such Investor. 
 5.12 Short Sales and Confidentiality Prior
to the Date Hereof. Other than consummating the transactions contemplated hereunder, such Investor has not, nor has any Person acting on behalf of or pursuant to any understanding with such Investor, directly or indirectly executed any purchases
or sales, including Short Sales, of the securities of the Company during the period commencing as of the time that such Investor was first contacted by the Company, the Placement Agent or any other Person regarding the transactions contemplated
hereby and ending immediately prior to the date hereof. Notwithstanding the foregoing, in the case of an Investor that is a multi-managed investment vehicle whereby separate portfolio managers manage separate portions of such Investor’s
assets and the portfolio managers have no direct knowledge of the investment decisions made by the portfolio managers managing other portions of such Investor’s assets, the representation set forth above shall only apply with respect to the
portion of assets managed by the portfolio manager that made the investment decision to purchase the Securities covered by this Agreement. Other than to other Persons party to this Agreement and their representatives, such Investor has
maintained the confidentiality of all non-public disclosures made to it in connection with this transaction (including the existence and terms of this transaction). Notwithstanding the foregoing, for avoidance
of doubt, nothing contained herein shall constitute a representation or warranty, or preclude any actions, with respect to the identification of the availability of, or securing of, available shares to borrow in order to effect Short Sales or
similar transactions in the future. 
 5.13 No Government Recommendation or Approval. Such Investor understands that no United States
federal or state agency, or similar agency of any other country, has reviewed, approved, passed upon, or made any recommendation or endorsement of the Company or the purchase of the Securities. 

5.15    No Rule 506 Disqualifying Activities. Such Investor has not taken any of the actions set forth in, and is
not subject to, the disqualification provisions of Rule 506(d)(1) of the 1933 Act. 
 5.16    Residency. Such
Investor is a resident of the jurisdiction specified below its address on the Schedule of Investors. 

6.    Conditions to Closing. 

6.1.    Conditions to the Investors’ Obligations. The obligation of each Investor to purchase Closing
Securities at the Closing is subject to the fulfillment to such Investor’s satisfaction, on or prior to the Closing Date, of the following conditions, any of which may be waived by such Investor (as to itself only): 

(a)    The representations and warranties made by the Company in Section 4 hereof shall be true and correct in all
material respects as of the date hereof and on the Closing 

  
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Date, except to the extent any such representation or warranty expressly speaks as of an earlier date, in which case such representation or warranty shall be true and correct in all material
respects as of such earlier date. The Company shall have performed in all material respects all obligations and covenants herein required to be performed by it on or prior to the Closing Date. 

(b)    The Company shall have obtained any and all consents, permits, approvals, registrations and waivers necessary for
consummation of the purchase and sale of the Closing Securities and the consummation of the other transactions contemplated by the Transaction Documents, all of which shall be in full force and effect. 

(c)    The Company shall have executed and delivered the Registration Rights Agreement. 

(d)    The Company shall have filed with Nasdaq a Notification Form: Listing of Additional Shares for the listing of the
Shares and the Warrant Shares. 
 (e)    No judgment, writ, order, injunction, award or decree of or by any court, or
judge, justice or magistrate, including any bankruptcy court or judge, or any order of or by any governmental authority, shall have been issued, and no action or proceeding shall have been instituted by any governmental authority, enjoining or
preventing the consummation of the transactions contemplated hereby or in the other Transaction Documents. 
 (f)    The
Company shall have received gross proceeds of at least $25 million from the sale of the Closing Securities. 

(g)    The Company shall have delivered a Certificate, executed on behalf of the Company by its Chief Executive Officer or
its Chief Financial Officer, dated as of the Closing Date, certifying to the fulfillment of the conditions specified in subsections (a), (b), (d), (e), (f), (i) and (j) of this Section 6.1. 

(h)    The Company shall have delivered a Certificate, executed on behalf of the Company by its Secretary, dated as of the
Closing Date, certifying the resolutions adopted by the Board approving the transactions contemplated by this Agreement and the other Transaction Documents and the issuance of the Closing Securities, certifying the current versions of the
Certificate of Incorporation and Bylaws of the Company and certifying as to the signatures and authority of persons signing the Transaction Documents and related documents on behalf of the Company. 

(i)    The Board shall have, effective as of the Closing, (i) elected Nolan Sigal to the Board as a Class II
director (with an initial term expiring at the Company’s 2019 annual meeting of stockholders, which is to be held on June 19, 2019), (ii) determined to nominate Dr. Sigal for election as a Class II director at the 2019 annual
meeting of stockholders (with an initial term expiring at the Company’s 2022 annual meeting of stockholders) and to recommend that the Company’s stockholders vote “for” Dr. Sigal at the 2019 annual meeting of stockholders,
(iii) appointed Dr. Sigal to the compensation committee and the nominating and governance committee of the Board and (iv) adopted written policies to require that the approval of the following matters by the Board will require a vote
of at least two-thirds of the independent and disinterested members of the Board to (a) any increase in the Company’s aggregate indebtedness for borrowed money to any amount exceeding
$2 million; (b) any transaction with Affiliates or related party transactions, (c) any increase in the size of the Board and (d) any amendment to the policies contemplated by clauses (a), (b) and (c). 

  
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 (j)    The Investors shall have received an opinion from Wilmer Cutler
Pickering Hale and Dorr LLP, the Company’s counsel, dated as of the Closing Date, in form and substance reasonably acceptable to the Placement Agent and addressing such legal matters as the Investors may reasonably request. 

(k)    No stop order or suspension of trading shall have been imposed by Nasdaq, the SEC or any other governmental or
regulatory body with respect to public trading in the Common Stock. 
 6.2.    Conditions to Obligations of the
Company. The Company’s obligation to sell and issue Closing Securities at the Closing is subject to the fulfillment to the satisfaction of the Company on or prior to the Closing Date of the following conditions, any of which may be waived
by the Company: 
 (a)    The representations and warranties made by the Investors in Section 5 hereof shall be true
and correct in all material respects as of the date hereof, and shall be true and correct in all material respects on the Closing Date with the same force and effect as if they had been made on and as of said date. The Investors shall have performed
in all material respects all obligations and covenants herein required to be performed by them on or prior to the Closing Date. 

(b)    The Investors shall have executed and delivered the Registration Rights Agreement and each Investor Questionnaire.

 (c)    Any Investor purchasing Closing Securities at the Closing shall have paid in full its Subscription Amount to
the Company. 
 6.3.    Termination of Obligations to Effect Closing; Effects. 

(a)    The obligations of the Company, on the one hand, and the Investors, on the other hand, to effect the Closing shall
terminate as follows: 
 (i)    Upon the mutual written consent of the Company and Investors that agreed to purchase a
majority of the Closing Securities to be issued and sold pursuant to this Agreement; 
 (ii)    By the Company if any
of the conditions set forth in Section 6.2 shall have become incapable of fulfillment, and shall not have been waived by the Company; 

(iii)    By an Investor (with respect to itself only) if any of the conditions set forth in Section 6.1 shall have
become incapable of fulfillment, and shall not have been waived by the Investor; or 

  
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 (iv)    By either the Company or any Investor (with respect to itself
only) if the Closing has not occurred on or prior to fifth Trading Day following the date of this Agreement; 
 provided, however, that, except in the case
of clause (i) above, the party seeking to terminate its obligation to effect the Closing shall not then be in breach of any of its representations, warranties, covenants or agreements contained in this Agreement or the other Transaction
Documents if such breach has resulted in the circumstances giving rise to such party’s seeking to terminate its obligation to effect the Closing. 

(b)    In the event of termination by the Company or any Investor of its obligations to effect the Closing pursuant to
this Section 6.3, written notice thereof shall be given to the other Investors by the Company and the other Investors shall have the right to terminate their obligations to effect the Closing upon written notice to the Company and the other
Investors. Nothing in this Section 6.3 shall be deemed to release any party from any liability for any breach by such party of the terms and provisions of this Agreement or the other Transaction Documents or to impair the right of any party to
compel specific performance by any other party of its obligations under this Agreement or the other Transaction Documents. 

7.    Covenants and Agreements of the Company. 

7.1.    No Conflicting Agreements. The Company will not take any action, enter into any agreement or make any
commitment that would conflict or interfere in any material respect with the Company’s obligations to the Investors under the Transaction Documents. 

7.2.    Nasdaq Listing; Depository Trust Company. The Company will use commercially reasonable efforts to continue
the listing and trading of its Common Stock on Nasdaq and, in accordance, therewith, will use commercially reasonable efforts to comply in all respects with the Company’s reporting, filing and other obligations under the bylaws or rules of such
market or exchange, as applicable. The Company will use commercially reasonable efforts to maintain the eligibility of its Common Stock for electronic transfer through the Depository Trust Company or another established clearing corporation. 

7.3.    Termination of Covenants. The provisions of Sections 7.1 and 7.2 shall terminate and be of no further
force and effect on the date on which the Company’s obligations under the Registration Rights Agreement to register or maintain the effectiveness of any registration covering the Registrable Securities (as such term is defined in the
Registration Rights Agreement) shall terminate. 
 7.4.    Annual Meeting; Board of Directors. The Company will
hold its 2019 annual meeting of stockholders on June 19, 2019. The Company will reduce the size of the Board to seven directors at such annual meeting, unless otherwise approved by a vote of at least a
two-thirds of the independent and disinterested members of the Board. 

7.5.    Transfer Restrictions. 

(a)    The Securities may only be disposed of in compliance with state and federal securities laws. In connection with any
transfer of Securities other than pursuant to an 

  
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effective registration statement or Rule 144, to the Company or to an Affiliate of an Investor or in connection with a pledge as contemplated in Section 7.5(b), the Company may require the
transferor thereof to provide to the Company an opinion of counsel selected by the transferor and reasonably acceptable to the Company, the form and substance of which opinion shall be reasonably satisfactory to the Company, to the effect that such
transfer does not require registration of such transferred Securities under the 1933 Act. As a condition of transfer, any such transferee shall agree in writing to be bound by the terms of this Agreement and the Registration Rights Agreement and
shall have the rights and obligations of an Investor under this Agreement and the Registration Rights Agreement. 

(b)    The Investors understands that, unless provided otherwise in this Agreement, a Common Warrant or a Pre-Funded Warrant, any of the Shares and Warrant Shares, whether certificated or in book-entry form, will be endorsed with the following legend: 

THIS SECURITY HAS NOT BEEN REGISTERED WITH THE SECURITIES AND EXCHANGE COMMISSION OR THE SECURITIES COMMISSION OF ANY STATE IN RELIANCE UPON AN
EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “SECURITIES ACT”), AND, ACCORDINGLY, MAY NOT BE OFFERED OR SOLD EXCEPT PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT OR PURSUANT TO AN
AVAILABLE EXEMPTION FROM, OR IN A TRANSACTION NOT SUBJECT TO, THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT AND IN ACCORDANCE WITH APPLICABLE STATE SECURITIES LAWS. THIS SECURITY MAY BE PLEDGED IN CONNECTION WITH A BONA FIDE MARGIN ACCOUNT
WITH A REGISTERED BROKER-DEALER OR OTHER LOAN WITH A FINANCIAL INSTITUTION THAT IS AN “ACCREDITED INVESTOR” AS DEFINED IN RULE 501(a) UNDER THE SECURITIES ACT OR OTHER LOAN SECURED BY SUCH SECURITIES. 

An Investor may from time to time pledge pursuant to a bona fide margin agreement with a registered broker-dealer or grant a security interest
in some or all of the Securities to a financial institution that is an “accredited investor” as defined in Rule 501(a) under the 1933 Act and who agrees to be bound by the provisions of this Agreement and, if required under the terms of
such arrangement, such Investor may transfer pledged or secured Securities to the pledgees or secured parties in compliance with applicable law. Such a pledge or transfer would not be subject to approval of the Company and no legal opinion of legal
counsel of the pledgee, secured party or pledgor shall be required in connection therewith. Further, no notice shall be required of such pledge. At the applicable Investor’s expense, the Company will execute and deliver such reasonable
documentation as a pledgee or secured party of Securities may reasonably request in connection with a pledge or transfer of the Securities. 

(c)    Notwithstanding Section 7.5(b), upon the written request of an Investor, any legend (including the legend set
forth in Section 7.5(b) hereof) on the Shares or Warrant Shares held by such Investor may be removed (i) while a registration statement (including the Registration Statement) covering the resale of such security is effective under the 1933
Act, (ii) following any sale of such Shares or Warrant Shares pursuant to Rule 144, (iii) if such Shares or Warrant Shares are eligible for sale under Rule 144 without the requirement to be in compliance


  
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with Rule 144(c)(1), or (iv) if such legend is not required under applicable requirements of the 1933 Act (including judicial interpretations and pronouncements issued by the staff of the
Commission), subject in the case of clauses (ii), (iii) and (iv) to receipt from the Investor by the Company and the Transfer Agent of customary representations reasonably acceptable to the Company and the Transfer Agent in connection with such
request. Upon such request, the Company shall (A) deliver to the Transfer Agent irrevocable instructions to the Transfer Agent to remove the legend, and (B) cause its counsel to deliver to the Transfer Agent one or more legal opinions to
the effect that the removal of such legend in such circumstances may be effected under the 1933 Act if required by the Transfer Agent to effect the removal of the legend in accordance with the provisions of this Agreement. If all or any portion of a
Common Warrant is exercised and (i) a registration statement (including the Registration Statement) covering the resale of such security is then effective under the 1933 Act, (ii) the Warrant Shares issuable upon such exercise are then
eligible for sale under Rule 144 and without the requirement to be in compliance with Rule 144(c)(1), or (iii) if a legend is not required under applicable requirements of the 1933 Act (including judicial interpretations and pronouncements
issued by the staff of the Commission), then such Warrant Shares shall be issued free of all legends, subject in the case of clauses (ii) and (iii) to receipt from the Investor by the Company and the Transfer Agent of customary representations
reasonably acceptable to the Company and the Transfer Agent in connection therewith. The Company agrees that following the effective date of a registration statement covering the resale of the Shares and Warrant Shares or at such time as such legend
is no longer required under this Section 7.5(c), it will, no later than two Trading Days following the delivery by an Investor to the Company or the Transfer Agent of a request for legend removal and in the case of a Shares or Warrant Shares
evidenced by a physical certificate, the delivery of the physical certificate, and if relying on Rule 144, receipt from the Investor by the Company and the Transfer Agent of customary representations reasonably acceptable to the Company and the
Transfer Agent in connection therewith (such second Trading Day, the “Legend Removal Date”), deliver or cause to be delivered to such Investor, as may be requested by the Investor, a certificate or book-entry position evidencing such
Shares and Warrant Shares that is free from all restrictive and other legends or by crediting the account of the Investor’s or its designee’s account with The Depository Trust Company through its Deposit or Withdrawal at Custodian system
if the Company is then a participant in such system. The Company may not make any notation on its records or give instructions to the Transfer Agent that enlarge the restrictions on transfer set forth in Section 7(b). 

(d)    If the Company fails to deliver any such Shares or Warrant Shares free from all restrictive legends on or before
the applicable Legend Removal Date and if after the Legend Removal Date, due to the Company’s continuing failure to deliver such Shares or Warrant Shares, such Investor purchases (in an open market transaction or otherwise) shares of Common
Stock to deliver in satisfaction of a sale by such Investor of all or any portion of the Shares or Warrant Shares anticipated receiving from the Company without any restrictive legend, then the Company shall pay in cash to the Investor in an amount
equal to the excess of such Investor’s total purchase price (including brokerage commissions, if any) for the shares of Common Stock so purchased (the “Buy-In Price”) over the product of
(A) such number of shares of Common Stock the Company was required to deliver to such Investor by the Legend Removal Date multiplied by (B) the lowest closing sale price of the Common Stock on any Trading Day during the period commencing
on the date of the delivery by such Investor to the Company such shares of Common Stock and ending on the date of such delivery and payment under this clause (ii). 

  
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 (e)    Each Investor, severally and not jointly with the other
Investors, agrees with the Company (i) that such Investor will sell any Shares or Warrant Shares pursuant to either the registration requirements of the 1933 Act, including any applicable prospectus delivery requirements, or an exemption
therefrom, (ii) that if Shares or Warrant Shares are sold pursuant to a Registration Statement, they will be sold in compliance with the plan of distribution set forth therein, (iii) that if, after the effective date of the registration
statement covering the resale of the Shares and the Warrant Shares, such registration statement ceases to be effective and the Company has provided notice to such Investor to that effect, such Investor will sell Shares only in compliance with an
exemption from the registration requirements of the 1933 Act; and acknowledges that the removal of the restrictive legend from the Shares and Warrant Shares due to the effectiveness of a registration statement as set forth in Section 7.5(c) is
predicated upon the Company’s reliance upon this Agreement. 
 7.6.    Subsequent Equity Sales. 

(a)    From the date hereof until thirty (30) days after the effective date of the registration statement covering the
resale of the Shares, without the consent of the Required Investors, the Company shall not (A) issue shares of Common Stock or Common Stock Equivalents or (B) file with the SEC a registration statement under the 1933 Act relating to any
shares of Common Stock or Common Stock Equivalents, except pursuant to the Registration Rights Agreement. Notwithstanding the foregoing, the provisions of this Section 7.6(a) shall not apply to (i) the issuance of the Securities hereunder,
(ii) the issuance of Common Stock or Common Stock Equivalents upon the conversion or exercise of any securities of the Company outstanding on the date hereof or outstanding pursuant to clause (iii) or (iv) below, (iii) the issuance of
any Common Stock or Common Stock Equivalents pursuant to any Company stock-based compensation plans approved by the Company’s stockholders or in accordance with Nasdaq Stock Market Rule 5635(c)(4), (iv) the issuance of any Common Stock or
Common Stock Equivalents in connection with a transaction with an unaffiliated third party approved by the Board that includes a bona fide commercial relationship with the Company (including any joint venture, marketing or distribution arrangement,
strategic alliance, collaboration agreement or corporate partnering, intellectual property license agreement or acquisition agreement with the Company); provided, however, that the aggregate number of shares of Common Stock issued pursuant to clause
(iv) during the restricted period shall not exceed 10% of the total number of shares of Common Stock issued and outstanding immediately following the Closing. 

(b)    The Company shall not, and shall use its commercially reasonable efforts to ensure that no Affiliate of the Company
shall, sell, offer for sale or solicit offers to buy or otherwise negotiate in respect of any security (as defined in Section 2 of the 1933 Act) that will be integrated with the offer or sale of the Securities in a manner that would require the
registration under the 1933 Act of the sale of the Securities to the Investors, or that will be integrated with the offer or sale of the Securities for purposes of the rules and regulations of any trading market such that it would require
stockholder approval prior to the closing of such other transaction unless stockholder approval is obtained before the closing of such subsequent transaction. 

  
 23 













 7.7.    Preemptive Rights. 

(a)    Subject to the terms and conditions of this Section 7.7 and any applicable securities laws, if the Company
proposes to offer or sell any New Securities (a “Subsequent Financing”) for cash consideration, indebtedness or a combination thereof, then each Major Investor shall have the right to purchase the same securities as are offered in the
Subsequent Financing and at the same price as the securities offered in the Subsequent Financing and on the same other terms as such securities are offered to other investors in the Subsequent Financing in an amount of the Subsequent Financing up to
the Major Investor’s Pro-Rata Share (as defined below); provided that if the Subsequent Financing is an offering that is registered under the 1933 Act, the Major Investor will have the right to purchase
New Securities in a side-by-side private placement. For purposes of this Agreement, each Major Investor’s “Pro-Rata
Share” shall be equal to the number of Shares and Warrant Shares held by such Major Investor and its Affiliates plus the number of Warrant Shares then issuable upon exercise of the Warrants held by such Major Investor and its Affiliates
immediately prior to the closing of the Subsequent Financing (based upon documentation or written representation reasonably satisfactory to the Company), divided by the total number of shares of Common Stock outstanding (assuming full conversion
and/or exercise, as applicable, of all Warrants) immediately prior to the closing of the Subsequent Financing. 

(b)    At least five (5) Trading Days prior to the entering into a definitive agreement for a Subsequent Financing,
the Company shall deliver to the Major Investors a confidential notice of its intention to effect a Subsequent Financing (the “Subsequent Financing Notice”) describing in reasonable detail the proposed terms of such Subsequent Financing,
such Major Investor’s Pro-Rate Share and the estimated date and time at which the Company expects to enter into an definitive agreement for the sale of securities in the Subsequent Financing. 

(c)    If a Major Investor desires to participate in a Subsequent Financing, then such Major Investor must provide a
written notice to the Company by not later than 5:30 p.m. (New York City time) on the third (3rd) Trading Day after such Major Investor has received a Subsequent Financing Notice, stating the amount of such Major Investor’s elected
participation. If the Company receives no such notice from a Major Investor within the time period set forth herein, such Major Investor shall be deemed to have notified the Company that it does not elect to purchase any securities in
connection with such Subsequent Financing and the Company shall be free to sell such securities in the Subsequent Financing. The closing of any purchase of New Securities by a Major Investor shall occur concurrently with the sale of New
Securities in the Subsequent Financing and it shall be a condition to the participation of the Major Investor in the Subsequent Financing that the Major Investor further agree to execute such other documents and agreements as may reasonably be
requested of a Major Investor by the Company in connection with a Subsequent Financing. 
 (d)    Notwithstanding
anything to the contrary in this Section 7.7 and unless otherwise agreed by each Major Investor that has elected to participate in such Subsequent Financing, in the event the Company determines to abandon a Subsequent Financing, the Company
shall, or shall cause the managing underwriter(s) or placement agent(s), as the case may be, to confirm such abandonment to each such Major Investor in the same manner and on the same day as such abandonment is communicated to other potential
investors. If, by the 

  
 24 













 
twentieth (20th) day following delivery of the Subsequent Financing Notice, no public disclosure regarding a transaction with respect to the Subsequent Financing has been made, such Subsequent
Financing shall be deemed to have been abandoned and the applicable Major Investors shall be deemed to not be in possession of any material, non-public information with respect to the proposed Subsequent
Financing by the Company, unless the Company advises the applicable Major Investors that the Subsequent Financing has not been abandoned. The Company understands and confirms that the Major Investors may rely on this Section 7.7(d) when
effecting transactions in securities of the Company 
 (e)    The rights set forth in this Section 7.7 shall remain
in effect with respect to a particular Major Investor as long as such Major Investor and its Affiliates collectively own fifty percent (50%) or more of the number of shares of Common Stock owned by the Investor and its Affiliates immediately
following the Closing. 
 (f)    Notwithstanding the foregoing, this Section 7.7 shall not apply in respect of an
Exempt Issuance and all rights of a Major Investor pursuant to this Section 7.7 shall terminate upon the occurrence of a Fundamental Transaction as defined in the Common Warrant. 

7.8.    Short Sales and Confidentiality After the Date Hereof. Each Investor covenants that neither it nor any
Affiliates acting on its behalf or pursuant to any understanding with it will execute any Short Sales during the period from the date hereof until the earlier of such time as (i) the transactions contemplated by this Agreement are first
publicly announced or (ii) this Agreement is terminated in full. Each Investor covenants that until such time as the transactions contemplated by this Agreement are publicly disclosed by the Company, such Investor will maintain the
confidentiality of all disclosures made to it in connection with this transaction (including the existence and terms of this transaction). 

7.9.    Public Information. At any time during the period commencing from the six (6) month anniversary of the
Closing Date and ending at such time that all of the Shares and Warrant Shares of an Investor, if a registration statement is not available for the resale of all of the Shares and Warrant Shares of an Investor, may be sold without restriction or
limitation pursuant to Rule 144 and without the requirement to be in compliance with Rule 144(c)(1), if the Company shall (i) fail for any reason to satisfy the requirements of Rule 144(c)(1), including, without limitation, the failure to
satisfy the current public information requirements under Rule 144(c) or (ii) if the Company has ever been an issuer described in Rule 144(i)(1)(i) or becomes such an issuer in the future, and the Company shall fail to satisfy any condition set
forth in Rule 144(i)(2) (each, a “Public Information Failure”) then, as partial relief for the damages to any holder of Securities by reason of any such delay in or reduction of its ability to sell the Shares and Warrant Shares (which
remedy shall not be exclusive of any other remedies available at law or in equity), the Company shall pay to such Investor or its designee an amount in cash equal to one percent (1.0%) of the aggregate Purchase Price of such holder’s Securities
on the day of a Public Information Failure and on every thirtieth day (pro-rated for periods totaling less than thirty days) thereafter until the earlier of (i) the date such Public Information Failure is
cured and (ii) such time that such Public Information Failure no longer prevents a holder of Securities from selling such Shares and Warrant Shares pursuant to Rule 144 without any restrictions or limitations. The payments to which a holder
shall be entitled pursuant to this Section 4(p) are referred to herein as “Public Information Failure Payments.” Public Information Failure 

  
 25 













 
Payments shall be paid on the earlier of (I) the last day of the calendar month during which such Public Information Failure Payments are incurred and (II) the third Business Day after
the event or failure giving rise to the Public Information Failure Payments is cured. In the event the Company fails to make Public Information Failure Payments in a timely manner, such Public Information Failure Payments shall bear interest at the
rate of 1.0% per month (prorated for partial months) until paid in full. 
 8.    Survival and Indemnification.

 8.1.    Survival. The representations, warranties, covenants and agreements contained in this Agreement shall
survive the Closing of the transactions contemplated by this Agreement for the applicable statute of limitations. 

8.2.    Indemnification. The Company agrees to indemnify and hold harmless each Investor and its Affiliates and
their respective directors, officers, trustees, members, managers, employees and agents, and their respective successors and assigns, from and against any and all losses, claims, damages, liabilities and expenses (including without limitation
reasonable attorney fees and disbursements and other expenses reasonably incurred in connection with investigating, preparing or defending any action, claim or proceeding, pending or threatened and the costs of enforcement thereof) (collectively,
“Losses”) to which such Person may become subject (i) as a result of any breach of representation, warranty, covenant or agreement made by or to be performed on the part of the Company under the Transaction Documents or
(ii) arising from the Company’s fraud, gross negligence and willful misconduct in connection with the execution, delivery and performance by the Company of the Transaction Documents and the offer, issuance and sale of the Closing
Securities, and will reimburse any such Person for all such amounts as they are incurred by such Person. 

8.3.    Conduct of Indemnification Proceedings. Any person entitled to indemnification hereunder
shall (i) give prompt notice to the Company of any claim with respect to which it seeks indemnification and (ii) permit the Company to assume the defense of such claim with counsel reasonably satisfactory to the indemnified party;
provided that any person entitled to indemnification hereunder shall have the right to employ separate counsel and to participate in the defense of such claim, but the fees and expenses of such counsel shall be at the expense of such person
unless (a) the Company has agreed to pay such fees or expenses, (b) the Company shall have failed to assume the defense of such claim and employ counsel reasonably satisfactory to such person or (c) in the reasonable judgment of any
such person, based upon written advice of its counsel, a conflict of interest exists between such person and the Company with respect to such claims (in which case, if the person notifies the Company in writing that such person elects to employ
separate counsel at the expense of the Company, the Company shall not have the right to assume the defense of such claim on behalf of such person); and provided, further, that the failure of any indemnified party to give notice as
provided herein shall not relieve the Company of its obligations hereunder, except to the extent that such failure to give notice shall materially adversely affect the Company in the defense of any such claim or litigation. It is understood that the
Company shall not, in connection with any proceeding in the same jurisdiction, be liable for fees or expenses of more than one separate firm of attorneys at any time for all such indemnified parties. The Company will not, except with the consent of
the indemnified party, which consent shall not be unreasonably withheld, conditioned or delayed, 

  
 26 













 
consent to entry of any judgment or enter into any settlement that does not include as an unconditional term thereof the giving by the claimant or plaintiff to such indemnified party of a release
from all liability in respect of such claim or litigation. No indemnified party will, except with the consent of the Company, consent to entry of any judgment or enter into any settlement. 

9.    Miscellaneous. 

9.1.    Successors and Assigns. This Agreement may not be assigned by a party hereto without the prior written
consent of the Company or each of the Investors, as applicable, provided, however, that an Investor may assign its rights and delegate its duties hereunder in whole or in part to an Affiliate or to a third party acquiring some or all of its
Securities in a transaction complying with applicable securities laws without the prior written consent of the Company or the other Investors, provided such assignee agrees in writing to be bound by the provisions hereof that apply to Investors. The
provisions of this Agreement shall inure to the benefit of and be binding upon the respective permitted successors and assigns of the parties. Without limiting the generality of the foregoing, in the event that the Company is a party to a merger,
consolidation, share exchange or similar business combination transaction in which the Common Stock is converted into the equity securities of another Person, from and after the effective time of such transaction, such Person shall, by virtue of
such transaction, be deemed to have assumed the obligations of the Company hereunder, the term “Company” shall be deemed to refer to such Person and the term “Securities” shall be deemed to refer to the securities received by the
Investors in connection with such transaction. Nothing in this Agreement, express or implied, is intended to confer upon any party other than the parties hereto or their respective permitted successors and assigns any rights, remedies, obligations,
or liabilities under or by reason of this Agreement, except as expressly provided in this Agreement. 

9.2.    Counterparts; Faxes; E-mail. This Agreement may be executed in one
or more counterparts, each of which shall be deemed an original, but all of which together shall constitute one and the same instrument. This Agreement may also be executed via facsimile or e-mail, which shall
be deemed an original. 
 9.3.    Titles and Subtitles. The titles and subtitles used in this Agreement are used
for convenience only and are not to be considered in construing or interpreting this Agreement. 

9.4.    Notices. Unless otherwise provided, any notice required or permitted under this Agreement shall be given in
writing and shall be deemed effectively given as hereinafter described (i) if given by personal delivery, then such notice shall be deemed given upon such delivery, (ii) upon delivery, if given by facsimile, so long as the sender receives
a machine generated notice of delivery, (iii) upon delivery, if delivered by e-mail so long as the send does not receive an automatically generated notice of delivery failure, (iv) if given by mail,
then such notice shall be deemed given upon the earlier of (A) receipt of such notice by the recipient or (B) three days after such notice is deposited in first class mail, postage prepaid, and (v) if given by an internationally
recognized overnight air courier, then such notice shall be deemed given one Business Day after delivery to such carrier. All notices shall be addressed to the party to be notified at the address as follows, or at such other address as such party
may designate by ten days’ advance written notice to the other party: 

  
 27 













 If to the Company: 

Aileron Therapeutics, Inc. 
 490
Arsenal Way 
 Watertown, Massachusetts 02472 

Attention: Chief Financial Officer 

Email: ddougherty@aileronrx.com 

With a copy to: 
 Wilmer Cutler
Pickering Hale and Dorr LLP 
 60 State Street 

Boston, Massachusetts 02109 

Attention: Stuart M. Falber 

Email: stuart.falber@wilmerhale.com 

If to the Investors: 
 to the addresses set
forth on the signature pages hereto. 
 9.5.    Expenses. The parties hereto shall pay their own costs and
expenses in connection herewith regardless of whether the transactions contemplated hereby are consummated; it being understood that each of the Company and each Investor has relied on the advice of its own respective counsel. 

9.6.    Amendments and Waivers. Any term of this Agreement may be amended and the observance of any term of this
Agreement may be waived (either generally or in a particular instance and either retroactively or prospectively), only with the written consent of the Company and (a) prior to the Closing, Investors that agreed to purchase a majority of the
Shares to be issued and sold pursuant to this Agreement and (b) following the Closing, the Required Investors. Notwithstanding the foregoing, this Agreement may not be amended and the observance of any term of this Agreement may not be waived
with respect to any Investor without the written consent of such Investor unless such amendment or waiver applies to all Investors in the same fashion. Any amendment or waiver effected in accordance with this paragraph shall be binding upon
(i) prior to Closing, each Investor and (ii) following the Closing, each holder of any Securities purchased under this Agreement at the time outstanding, and in each case, each future holder of all such Securities and the Company. 

9.7.    Publicity. Except as set forth below, no public release or announcement concerning the transactions
contemplated hereby shall be issued by the Investors without the prior consent of the Company (which consent shall not be unreasonably withheld), except for such disclosure to Affiliates or limited partners on a
non-public basis consistent with public disclosure by the Company and as such release or announcement may be required by law or the applicable rules or regulations of any securities exchange or securities
market, in which case the Investors shall allow the Company, to the extent reasonably practicable in the circumstances, reasonable time to comment on such release or announcement in advance of such issuance. The Company shall not include the name of
any Investor in any press release or public announcement 

  
 28 













 
(which, for the avoidance of doubt, shall not include any SEC Filing) without the prior written consent of such Investor. By the Disclosure Time, the Company shall issue a press release
disclosing all material terms of transactions contemplated by this Agreement (the “Press Release”). No later than 5:30 p.m. (New York City time) on the first Business Day following the date this Agreement is executed, the Company will file
a Current Report on Form 8-K (the “8-K Filing”) attaching the press release described in the foregoing sentence as well as copies of the Transaction Documents.
In addition, the Company will make such other filings and notices in the manner and time required by the SEC or Nasdaq. The parties acknowledge that from and after the issuance of the Press Release, no Investor shall be in possession of any
material, nonpublic information received from the Company or any of its respective officers, directors, employees or agents, with respect to the transactions contemplated hereby that is not disclosed in the Press Release. The Company shall not, and
shall cause each of its officers, directors, employees and agents, not to, provide any Investor with any such material, nonpublic information regarding the Company from and after the filing of the Press Release without the express prior written
consent of such Investor. 
 9.8.    Severability. Any provision of this Agreement that is prohibited or
unenforceable in any jurisdiction shall, as to such jurisdiction, be ineffective to the extent of such prohibition or unenforceability without invalidating the remaining provisions hereof but shall be interpreted as if it were written so as to be
enforceable to the maximum extent permitted by applicable law, and any such prohibition or unenforceability in any jurisdiction shall not invalidate or render unenforceable such provision in any other jurisdiction. To the extent permitted by
applicable law, the parties hereby waive any provision of law which renders any provision hereof prohibited or unenforceable in any respect. 

9.9.    Entire Agreement. This Agreement, including the signature pages, Exhibits and the Disclosure Schedules, and
the other Transaction Documents constitute the entire agreement among the parties hereof with respect to the subject matter hereof and thereof and supersede all prior agreements and understandings, both oral and written, between the parties with
respect to the subject matter hereof and thereof. 
 9.10.    Further Assurances. The parties shall execute and
deliver all such further instruments and documents and take all such other actions as may reasonably be required to carry out the transactions contemplated hereby and to evidence the fulfillment of the agreements herein contained. 

9.11.    Governing Law; Consent to Jurisdiction; Waiver of Jury Trial. This Agreement shall be governed by, and
construed in accordance with, the internal laws of the State of New York without regard to the choice of law principles thereof. Each of the parties hereto irrevocably submits to the exclusive jurisdiction of the courts of the State of New York
located in New York County and the United States District Court for the Southern District of New York for the purpose of any suit, action, proceeding or judgment relating to or arising out of this Agreement and the transactions contemplated hereby.
Service of process in connection with any such suit, action or proceeding may be served on each party hereto anywhere in the world by the same methods as are specified for the giving of notices under this Agreement. Each of the parties hereto
irrevocably consents to the jurisdiction of any such court in any such suit, action or proceeding and to the laying of venue in such court. Each party hereto irrevocably waives any 

  
 29 













 
objection to the laying of venue of any such suit, action or proceeding brought in such courts and irrevocably waives any claim that any such suit, action or proceeding brought in any such court
has been brought in an inconvenient forum. EACH OF THE PARTIES HERETO WAIVES ANY RIGHT TO REQUEST A TRIAL BY JURY IN ANY LITIGATION WITH RESPECT TO THIS AGREEMENT AND REPRESENTS THAT COUNSEL HAS BEEN CONSULTED SPECIFICALLY AS TO THIS WAIVER.

 9.12.    Independent Nature of Investors’ Obligations and Rights. The obligations of each Investor under
any Transaction Document are several and not joint with the obligations of any other Investor, and no Investor shall be responsible in any way for the performance of the obligations of any other Investor under any Transaction Document. The decision
of each Investor to purchase Closing Securities pursuant to the Transaction Documents has been made by such Investor independently of any other Investor. Nothing contained herein or in any Transaction Document, and no action taken by any Investor
pursuant thereto, shall be deemed to constitute the Investors as a partnership, an association, a joint venture or any other kind of entity, or create a presumption that the Investors are in any way acting in concert or as a group with respect to
such obligations or the transactions contemplated by the Transaction Documents. Each Investor acknowledges that no other Investor has acted as agent for such Investor in connection with making its investment hereunder and that no Investor will be
acting as agent of such Investor in connection with monitoring its investment in the Securities or enforcing its rights under the Transaction Documents. Each Investor shall be entitled to independently protect and enforce its rights, including,
without limitation, the rights arising out of this Agreement or out of the other Transaction Documents, and it shall not be necessary for any other Investor to be joined as an additional party in any proceeding for such purpose. The Company
acknowledges that each of the Investors has been provided with the same Transaction Documents for the purpose of closing a transaction with multiple Investors and not because it was required or requested to do so by any Investor. 

9.13.    Limitation of Liability. Notwithstanding anything herein to the contrary, the Company acknowledges and
agrees that the liability of an Investor arising directly or indirectly under any Transaction Document of any and every nature whatsoever shall be satisfied solely out of the assets of such Investor and that no trustee, officer, other investment
vehicle or any other Affiliate of such Investor or any investor, shareholder or holder of shares of beneficial interest of such Investor shall be personally liable for any liabilities of such Investor. 

[remainder of page intentionally left blank] 

  
 30 













 IN WITNESS WHEREOF, the parties have executed this Agreement or caused their duly authorized
officers to execute this Agreement as of the date first above written. 
  

					
	COMPANY:	 	AILERON THERAPEUTICS, INC.
			
		 	By:	 	 /s/ Manuel C. Alves Aivado

		 	Name:	 	Manuel C. Alves Aivado
		 	Title:	 	Chief Executive Officer














					
	INVESTOR:	 	SATTER MEDICAL TECHNOLOGY PARTNERS, L.P.
			
		 	By:	 	Satter Medical Technology GP, L.P.
		 	Its:	 	General Partner
			
		 	By:	 	Satter Medical Technology UGP, LLC
		 	Its:	 	General Partner
			
		 	By:	 	Muneer A. Satter Revocable Trust
		 	Its:	 	Managing Member
			
		 	By:	 	 /s/ Muneer A. Satter

		 	Name:	 	Muneer A. Satter
		 	Title:	 	Trustee
		
	INVESTOR:	 	ARMISTICE CAPITAL MASTERFUND LLC
			
		 	By:	 	 /s/ Anthony Cordone

		 	Name:	 	Anthony Cordone
		 	Title:	 	CFO
		
	INVESTOR:	 	Jennison Global Healthcare Master Fund, Ltd.
			
		 	By:	 	Jennison Associates LLC, as the Investment Manager of Jennison Global Healthcare Master Fund, Ltd.
			
		 	By:	 	 /s/ David Chan

		 	Name:	 	David Chan
		 	Title:	 	Managing Director of Jennison Associates LLC
		
	INVESTOR:	 	Prudential Sector Funds, Inc. - PGIM Jennison Health Sciences Fund
			
		 	By:	 	Jennison Associates LLC, as the Subadvisor of Prudential Sector Funds, Inc. - PGIM Jennison - Health Sciences Fund
			
		 	By:	 	 /s/ David Chan

		 	Name:	 	David Chan
		 	Title:	 	Managing Director of Jennison Associates LLC
		
	INVESTOR:	 	Jenop Global Healthcare Fund Limited
			
		 	By:	 	Jennison Associates LLC, as the Investment Manager of Jenop Global Healthcare Fund Limited
			
		 	By:	 	 /s/ David Chan

		 	Name:	 	David Chan
		 	Title:	 	Managing Director of Jennison Associates LLC
	INVESTOR:	 	
			
		 	By:	 	 /s/ Scott Kapnick

		 	Name:	 	Scott Kapnick
		 	Title:	 	
		
	INVESTOR:	 	SABBY VOLATILITY WARRANT MASTER FUND, LTD.
			
		 	By:	 	 /s/ Robert Grundstein

		 	Name:	 	Robert Grundstein
		 	Title:	 	COO of Investment Manager
		
	INVESTOR:	 	SIGMA EMERGING MARKETS LTD.
			
		 	By:	 	 /s/ Rafael Urquia II

		 	Name:	 	Rafael Urquia II
		 	Title:	 	Secretary
		
	INVESTOR:	 	CVF, LLC
			
		 	By:	 	 /s/ Gerrit Adams

		 	Name:	 	Gerrit Adams
		 	Title:	 	Senior Associate
		
	INVESTOR:	 	Empery Asset Master, LTD
			
		 	By:	 	Empery Asset Management, LP, its authorized agent
			
		 	By:	 	 /s/ Brett S. Director

		 	Name:	 	Brett S. Director
		 	Title:	 	General Counsel of Empery Asset Management, LP
		
	INVESTOR:	 	Empery Tax Efficient, LP
			
		 	By:	 	Empery Asset Management, LP, its authorized agent
			
		 	By:	 	 /s/ Brett S. Director

		 	Name:	 	Brett S. Director
		 	Title:	 	General Counsel of Empery Asset Management, LP
		
	INVESTOR:	 	Empery Tax Efficient II, LP
			
		 	By:	 	Empery Asset Management, LP, its authorized agent
			
		 	By:	 	 /s/ Brett S. Director

		 	Name:	 	Brett S. Director
		 	Title:	 	General Counsel of Empery Asset Management, LP
		
	INVESTOR:	 	Lincoln Park Capital Fund, LLC
			
		 	By:	 	Lincoln Park Capital LLC
			
		 	By:	 	Rockledge Capital Corporation
			
		 	By:	 	 /s/ Joshua Scheinfeld

		 	Name:	 	Joshua Scheinfeld
		 	Title:	 	President
		
	INVESTOR:	 	DAFNA Lifescience LP
			
		 	By:	 	 /s/ Fariba Ghodsian

		 	Name:	 	Fariba Ghodsian
		 	Title:	 	C.I.O.
		
	INVESTOR:	 	DAFNA Lifescience Select LP
			
		 	By:	 	 /s/ Fariba Ghodsian

		 	Name:	 	Fariba Ghodsian
		 	Title:	 	C.I.O.
		
	INVESTOR:	 	Intracoastal Capital LLC
			
		 	By:	 	 /s/ Keith Goodman

		 	Name:	 	Keith Goodman
		 	Title:	 	Authorized Signatory
		
	INVESTOR:	 	CVI Investments Inc.
			
		 	By:	 	Heights Capital Management Its Authorized Agent
			
		 	By:	 	 /s/ Martin Kobinger

		 	Name:	 	Martin Kobinger
		 	Title:	 	Investment Manager
	INVESTOR:	 	
			
		 	By:	 	 /s/ Josef von Rickenbach

		 	Name:	 	Josef von Rickenbach
		 	Title:	 	Mg. Dir.
		
	INVESTOR:	 	Terry J. Gottlieb Revocable Trust
			
		 	By:	 	 /s/ Terry Gottlieb

		 	Name:	 	Terry Gottlieb
		 	Title:	 	Trustee














			
	Investor Information	 	
		
	Entity Name:	 	
		
	Contact Person:	 	
		
	Address:	 	
		
	City:	 	
		
	State:	 	
		
	Zip Code:	 	
		
	Telephone:	 	
		
	Facsimile:	 	
		
	Email:	 	
		
	Tax ID # or Social Security #:	 	
		
	Name in which Securities should be issued:	 	


  
 33 













 EXHIBIT A 

Schedule of Investors 
  

																									
	 Investor Name and Address
	 	Number of
Shares to
be
Purchased	 	 	Number of
Common Warrant
Shares
Underlying
Common
Warrants
Purchased	 	 	Number of
Pre-Funded
Warrants to be
Purchased	 	 	Number
of
Pre-Funded
Warrant
Shares Underlying
Pre-Funded
Warrants
Purchased	 	 	Number of Common
Warrant Shares
Underlying
Common Warrants
Purchased	 	 	Aggregate
Purchase Price of
Closing Securities	 
	Satter Medical Technology Partners, L.P. 
676 N. Michigan Avenue, Suite 4000 
Chicago IL, 60611	 	 	3,731,343	 	 	 	3,731,343	 	 	 	0	 	 	 	0	 	 	 	0	 	 	$	7,499,999.43	 
							
	Armistice Capital Masterfund LLC 
510 Madison Ave. 7th Floor 
New York, NY 10022	 	 	2,137,089	 	 	 	2,137,089	 	 	 	1,096,741	 	 	 	1,096,741	 	 	 	1,096,741	 	 	$	6,499,998.30	 
							
	Prudential Sector Funds, Inc. - PGIM Jennison Health Sciences Fund 
c/o Jennison Associates LLC 
466 Lexington Avenue 
New York, NY 10017	 	 	895,522	 	 	 	895,522	 	 	 	0	 	 	 	0	 	 	 	0	 	 	$	1,799,999.22	 
							
	Jennison Global Healthcare Master Fund, Ltd. 
c/o Jennison Associates LLC 
466 Lexington Avenue 
New York, NY 10017	 	 	402,985	 	 	 	402,985	 	 	 	0	 	 	 	0	 	 	 	0	 	 	$	809,999.85	 
							
	Jenop Global Healthcare Fund Limited 
c/o Jennison Associates LLC 
466 Lexington Avenue 
New York, NY 10017	 	 	243,781	 	 	 	243,781	 	 	 	0	 	 	 	0	 	 	 	0	 	 	$	489,999.81	 
							
	Scott Kapnick 
[**]	 	 	1,492,537	 	 	 	1,492,537	 	 	 	0	 	 	 	0	 	 	 	0	 	 	$	2,999,999.37	 
							
	SABBY VOLATILITY WARRANT MASTER FUND, LTD. 
10 Mountainview Road, Suite 208 
Upper Saddle River, NJ 07458	 	 	995,024	 	 	 	995,024	 	 	 	0	 	 	 	0	 	 	 	0	 	 	$	1,999,998.24	 
							
	 Sigma Emerging Markets Ltd. 
OMC Chambers, Wickhams Cay 1 
Road Town, Tortola 
British Virgin Islands 
Attn.: Jaime J.
Montealegre
  
 WITH A COPY TO:

 
 Fox Horan & Camerini LLP 
Attn.: Rafael Urquia II, Esq. 
885 Third
Avenue, 17th Floor 
New York, NY 10022
	 	 	621,890	 	 	 	621,890	 	 	 	0	 	 	 	0	 	 	 	0	 	 	$	1,249,998.90	 
							
	CVF, LLC 
222 N. LaSalle St, Suite 2000 
Chicago, IL 60601	 	 	547,268	 	 	 	547,268	 	 	 	0	 	 	 	0	 	 	 	0	 	 	$	1,100,008.68	 


  
 34 














																									
							
	Empery Tax Efficient II, LP 
By: Empery Asset Management, LP, its 
authorized agent 
One Rockefeller Plaza, Suite 1205 
New York City, NY 10020	 	 	148,404	 	 	 	148,404	 	 	 	0	 	 	 	0	 	 	 	0	 	 	$	298,292.04	 
							
	Empery Asset Master, LTD 
By: Empery Asset Management, LP, its 
authorized agent 
One Rockefeller Plaza, Suite 1205 
New York City, NY 10020	 	 	82,944	 	 	 	82,944	 	 	 	0	 	 	 	0	 	 	 	0	 	 	$	166,717.44	 
							
	Empery Tax Efficient, LP 
By: Empery Asset Management, LP, its 
authorized agent 
One Rockefeller Plaza, Suite 1205 
New York City, NY 10020	 	 	17,408	 	 	 	17,408	 	 	 	0	 	 	 	0	 	 	 	0	 	 	$	34,990.08	 
							
	Lincoln Park Capital Fund, LLC 
440 N. Wells St., Suite 410 
Chicago, IL 60654	 	 	199,004	 	 	 	199,004	 	 	 	0	 	 	 	0	 	 	 	0	 	 	$	399,998.04	 
							
	DAFNA Lifescience LP 
10990 Wilshire Blvd., Suite 1400 
Los Angeles, CA 90024 
	 	 	69,652	 	 	 	69,652	 	 	 	0	 	 	 	0	 	 	 	0	 	 	$	140,000.52	 
							
	DAFNA Lifescience Select LP 
10990 Wilshire Blvd., Suite 1400 
Los Angeles, CA 90024	 	 	29,850	 	 	 	29,850	 	 	 	0	 	 	 	0	 	 	 	0	 	 	$	59,998.50	 
							
	Intracoastal Capital LLC 
2211A Lakeside Dr. 
Bannockburn, IL 60015	 	 	74,626	 	 	 	74,626	 	 	 	0	 	 	 	0	 	 	 	0	 	 	$	149,998.26	 
							
	CVI Investments Inc., 
by Heights Capital Management its Authorized Agent 
101 California St., Suite 3250 
San Francisco, CA 94111	 	 	74,626	 	 	 	74,626	 	 	 	0	 	 	 	0	 	 	 	0	 	 	$	149,998.26	 
							
	 Josef von Rickenbach
 [**]
	 	 	49,752	 	 	 	49,752	 	 	 	0	 	 	 	0	 	 	 	0	 	 	$	100,001.52	 
							
	Terry J. Gottlieb Revocable Trust 
9913 Casabella Way 
Bonita Springs, FL 34135	 	 	24,877	 	 	 	24,877	 	 	 	0	 	 	 	0	 	 	 	0	 	 	$	50,002.77	 
		 	  
	  
	 	 	  
	  
	 	 	  
	  
	 	 	  
	  
	 	 	  
	  
	 	 	  
	  
	 
	 TOTAL
	 	 	11,838,582	 	 	 	11,838,582	 	 	 	1,096,741	 	 	 	1,096,741	 	 	 	1,096,741	 	 	$	25,999,999.23	 
		 	  
	  
	 	 	  
	  
	 	 	  
	  
	 	 	  
	  
	 	 	  
	  
	 	 	  
	  
	 


  
 35 













 EXHIBIT B 

Form of Common Warrant 

  
 36 













 EXHIBIT C 

Form of Pre-Funded Warrant 

  
 37 













 EXHIBIT D 

Registration Rights Agreement 

  
 38 













 EXHIBIT E 

Investor Questionnaire 

  
 39 













 Disclosure Schedules 

None. 

  
 40