AILERON THERAPEUTICS, INC. (A corporation existing under the laws of the State of Delaware)

Exhibit 10.3

NEITHER THIS SECURITY NOR THE SECURITIES INTO WHICH THIS SECURITY IS EXERCISABLE HAVE 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 AND THE SECURITIES ISSUABLE UPON EXERCISE OF THIS SECURITY MAY BE PLEDGED IN CONNECTION WITH A BONA FIDE MARGIN ACCOUNT OR OTHER LOAN SECURED BY SUCH SECURITIES.

Number of Warrants:                                                                                                                               Warrant Certificate No.                 

AILERON THERAPEUTICS, INC.

(A corporation existing under the laws of the State of Delaware)

THIS COMMON STOCK PURCHASE WARRANT (the “Warrant”) certifies that, for value received,                      (the “Holder”), is entitled, upon the terms and subject to the limitations on exercise and the conditions hereinafter set forth, including without limitation Section 2(d), at any time on or after the date hereof and on or prior to 5:00 p.m. (New York time) on                     , 2024 (the “Expiry Time”) but not thereafter, to subscribe for and purchase from Aileron Therapeutics, Inc., a Delaware corporation (the “Company”), up to                      shares (the “Warrant Shares”) of Common Stock, par value $0.001 per share, of the Company (the “Common Stock”), subject to adjustment as provided herein. The purchase price of one share of Common Stock under this Warrant shall be equal to the Exercise Price, as defined in Section 2(b).

Section 1.    Definitions. Capitalized terms used and not otherwise defined herein shall have the meanings set forth in that certain Securities Purchase Agreement (the “Securities Purchase Agreement”), dated March 28, 2019, among the Company and the purchasers signatory thereto.

Section 2.    Exercise.

a)    Exercise of Warrant. Exercise of the purchase rights represented by this Warrant may be made, in whole or in part, at any time or times on or after the date of issuance of this Warrant and on or before the Expiry Time by delivery to the Company in accordance with the notice provisions of section 5(h) hereof of a duly executed facsimile copy or PDF copy submitted by e-mail (or e-mail attachment) of the Notice of Exercise in the form annexed hereto (the “Notice of Exercise”). Within two (2) Trading Days following the date of delivery of the Notice of Exercise, the Holder shall deliver the aggregate Exercise Price for the shares being purchased as specified in the applicable Notice of Exercise by wire transfer or cashier’s check drawn on a United States bank unless the cashless exercise procedure specified in Section 2(c)

below is specified in the applicable Notice of Exercise. No ink-original Notice of Exercise shall be required, nor shall any medallion guarantee (or other type of guarantee or notarization) of any Notice of Exercise be required. Notwithstanding anything herein to the contrary, the Holder shall not be required to physically surrender this Warrant to the Company until the Holder has purchased all of the Warrant Shares available hereunder and the Warrant has been exercised in full, in which case, the Holder shall surrender this Warrant to the Company for cancellation within three (3) Trading Days of the date on which the final Notice of Exercise is delivered to the Company. Partial exercises of this Warrant resulting in purchases of a portion of the total number of Warrant Shares available hereunder shall have the effect of lowering the outstanding number of Warrant Shares purchasable hereunder in an amount equal to the applicable number of Warrant Shares purchased. The Holder and the Company shall maintain records showing the number of Warrant Shares purchased and the date of such purchases. The Company shall deliver any objection to any Notice of Exercise within one Trading Day of receipt of such notice. The Holder and any assignee, by acceptance of this Warrant, acknowledge and agree that, by reason of the provisions of this paragraph, following the purchase of a portion of the Warrant Shares hereunder, the number of Warrant Shares available for purchase hereunder at any given time may be less than the amount stated on the face hereof.

b)    Exercise Price. The exercise price of the Common Stock under this Warrant shall be $2.00 per share, subject to adjustment hereunder.

c)    Cashless Exercise. This Warrant may also be exercised, in whole or in part, by means of a “cashless exercise” in which the Holder shall be entitled to receive a number of Warrant Shares equal to the quotient obtained by dividing [(A-B)*(X)] by (A), where:

If Warrant Shares are issued in such a cashless exercise to the holder of this Warrant, the parties acknowledge and agree that in accordance with Section 3(a)(9) of the Securities Act of 1933, as amended (the “Securities Act”), the Warrant Shares shall take on the characteristics of the Warrants being exercised, and, for purposes of Rule 144, the holding period of the Warrant Shares being issued may be tacked on to the holding period of this Warrant. The Company agrees not to take any position contrary to this Section 2(c).

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The “VWAP” means, for any date, the price determined by the first of the following clauses that applies: (a) if the Common Stock is then listed or quoted on a Trading Market, the daily volume weighted average price of the Common Stock for such date (or the nearest preceding date) on the Trading Market as reported by Bloomberg Financial L.P. (based on a Trading Day from 9:30 a.m. Eastern Time to 4:02 p.m. Eastern Time); (b) the volume weighted average price of the Common Stock for such date (or the nearest preceding date) on the OTCQB or OTCQX as applicable or (c) if the Common Stock is not then listed or quoted on the OTC QB or OTCQX and if prices for the Common Stock are then reported in the “Pink Sheets” published by the OTC Markets Group (or a similar organization or agency succeeding to its functions of reporting prices), the most recent bid price per share of the Common Stock so reported; or (d) in all other cases, the fair market value of a share of Common Stock as determined by a good faith determination of the Company’s Board of Directors.

d)    [Percentage Limitation.¹ Notwithstanding anything to the contrary contained herein, other than as provided in Section 2(f) and Section 3(c), the number of Warrant Shares that may be acquired by the Holder upon any exercise of this Warrant (or otherwise in respect hereof) shall be limited to the extent necessary to ensure that, following such exercise (or other issuance), the total number of shares of Common Stock then beneficially owned by the Holder and its affiliates and any other Persons whose beneficial ownership of Common Stock would be aggregated with the Holder’s for purposes of Section 13(d) of the Securities Exchange Act of 1934, as amended (the “1934 Act”), of the 1934 Act and the rules and regulations promulgated thereunder, including any “group” of which the Holder is a member, does not exceed [4.999]% of the total number of then issued and outstanding shares of Common Stock (including for such purpose the shares of Common Stock issuable upon such exercise), it being acknowledged by the Holder that the Company is not representing to such Holder that such calculation is in compliance with Section 13(d) of the 1934 Act and such Holder is solely responsible for any schedules required to be filed in accordance therewith. To the extent that the limitation contained in this Section 2(d) applies, the determination of whether this Warrant is exercisable (in relation to other securities owned by such Holder) and of which a portion of this Warrant is exercisable shall be in the sole discretion of a Holder, and the submission of a Notice of Exercise shall be deemed to be the Holder’s determination of whether this Warrant is exercisable (in relation to other securities owned by such Holder) and of which portion of this Warrant is exercisable, in each case subject to such aggregate percentage limitation, and the Company shall have no obligation to verify or confirm the accuracy of such determination. In addition, a determination under this Section 2(d) as to any group status shall be determined in accordance with Section 13(d) of the 1934 Act and the rules and regulations promulgated thereunder. For purposes of this Section 2(d), in determining the number of outstanding shares of Common Stock, the Holder may rely on the number of outstanding shares of Common Stock as reflected in (x) the Company’s most recent Form 10-Q or Form 10-K, as the case may be, (y) a more recent public announcement by the Company or (z) any other more recent notice by the Company or the transfer agent of the Company (the “Transfer Agent”) setting forth the number

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of shares of Common Stock outstanding. Upon the written request of the Holder, the Company shall within three (3) Trading Days confirm in writing to such Holder the number of shares of Common Stock then outstanding. Notwithstanding the foregoing, by written notice to the Company, which will not be effective until the sixty-first (61st) day after such notice is delivered to the Company, the Holder may waive the provisions of this Section 2(d) (but such waiver will not affect any other holder) or change the beneficial ownership limitation to such percentage of the number of shares of the Common Stock outstanding immediately after giving effect to the issuance of shares of Common Stock upon exercise of this Warrant, as the Holder shall determine, in its sole discretion, subject to Section 2(e), and the provisions of this Section 2(d) shall continue to apply[; provided that in no event shall such percentage limitation be increased to more than 9.999%]. Upon such a change by a Holder of the beneficial ownership limitation from such [4.999]% limitation to such other percentage limitation, the beneficial ownership limitation may not be further waived by such Holder without first providing the minimum 61-day notice required by this Section 2(d).]

[e)    Notwithstanding anything to the contrary contained herein, including Section 2(d), other than as provided in Section 2(f) and Section 3(c), the Company shall not effect any exercise of this Warrant, and the Holder shall not be entitled to exercise this Warrant for a number of Warrant Shares in excess of that number of Warrant Shares which, upon giving effect to such exercise, would cause (i) the aggregate number of shares of Common Stock beneficially owned by the Holder and its Affiliates and any other Persons whose beneficial ownership of Common Stock would be aggregated with the Holder’s for purposes of Section 13(d) of the 1934 Act and the rules and regulations promulgated thereunder, including any “group” of which the Holder is a member, to exceed 19.99% of the total number of issued and outstanding shares of Common Stock of the Company following such exercise, or (ii) the combined voting power of the securities of the Company beneficially owned by the Holder and its Affiliates and any other Persons whose beneficial ownership of Common Stock would be aggregated with the Holder’s for purposes of Section 13(d) of the 1934 Act to exceed 19.99% of the combined voting power of all of the securities of the Company then outstanding following such exercise. For purposes of this Section 2(e), the aggregate number of shares of Common Stock or voting securities beneficially owned by the Holder and its Affiliates and any other Persons whose beneficial ownership of Common Stock would be aggregated with the Holder’s for purposes of Section 13(d) of the 1934 Act shall include the shares of Common Stock issuable upon the exercise of this Warrant with respect to which such determination is being made, but shall exclude the number of shares of Common Stock which would be issuable upon (x) exercise of the remaining unexercised and non-cancelled portion of this Warrant by the Holder and (y) exercise or conversion of the unexercised, non-converted or non-cancelled portion of any other securities of the Company that do not have voting power (including without limitation 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, right, option, warrant or other instrument that is at any time convertible into or exercisable or exchangeable for, or otherwise entitles the holder thereof to receive, Common Stock), is subject to a limitation on conversion or exercise analogous to the limitation contained herein and is beneficially owned by the Holder or any of its Affiliates and other Persons whose beneficial ownership of Common Stock would be aggregated with the Holder’s for purposes of Section 13(d) of the 1934 Act.]²

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f)    Neither Section 2(d) nor Section 2(e) shall restrict the number of shares of Common Stock which a Holder may receive or beneficially own in order to determine the amount of securities or other consideration that such Holder may receive in the event of a Fundamental Transaction as contemplated in Section 3(c) of this Warrant.

g)    Mechanics of Exercise.

i.    Authorization of Warrant Shares. The Company covenants that all Warrant Shares which may be issued upon the exercise of the purchase rights represented by this Warrant will, upon exercise of the purchase rights represented by this Warrant and payment to the Company of the purchase price therefor, be duly authorized, validly issued, fully paid and nonassessable and free from all taxes, liens and charges in respect of the issue thereof (other than taxes in respect of any transfer occurring contemporaneously with such issue).

ii.    Delivery of Certificates Upon Exercise. Certificates for shares purchased hereunder shall be transmitted by the Transfer Agent to the Holder in electronic book entry form to the account of such Holder or, upon request of the Holder, by physical delivery to the address specified by the Holder in the Notice of Exercise within two (2) Trading Days following the delivery of the applicable Notice of Exercise (the “Warrant Share Delivery Date”), provided, however, that if Holder shall request physical delivery of certificates representing the Warrant Shares or shall fail to remit payment for the Warrant Shares within two (2) Trading Days following the date of delivery of the Notice of Exercise pursuant to Section 2(a) (other than in the case of a cashless exercise pursuant to Section 2(c)), there shall be no requirement to deliver such certificates on or prior to the Warrant Share Delivery Date. This Warrant shall be deemed to have been exercised on the date the Exercise Price and the Notice of Exercise is delivered to the Company (or in the case of a cashless exercise pursuant to Section 2(c), the date Notice of Exercise is delivered). The Warrant Shares shall be deemed to have been issued, and Holder shall be deemed to have become a holder of record of such shares for all purposes, as of such date irrespective of the date such Warrant Shares are credited in book entry to the Holder’s account. Notwithstanding the foregoing, if requested by the Holder, the Company shall cause the Warrant Shares purchased hereunder to be transmitted by the Transfer Agent to the Holder by crediting the account of the Holder’s or its designee’s balance account with The Depository Trust Company through its Deposit or Withdrawal at Custodian system (“DWAC”) if the Company is then a participant in such system and either (A) a registration statement covering the resale of Warrant Shares by the Holder is effective under the Securities Act or (B) the Warrant Shares are eligible for sale under Rule 144 and without the requirement to be in compliance with Rule 144(c)(1) (assuming cashless exercise of the Warrants), irrespective of the date. The Company agrees to maintain a transfer agent that is a participant in the FAST program so long as this Warrant remains outstanding and exercisable. Solely for purposes of Regulation SHO, this Warrant shall be deemed to have been exercised upon delivery of a Notice of Exercise so long as the applicable Exercise Price is delivered to the Company no later than two Trading Days following the delivery of the applicable Notice of Exercise.

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iii.    Delivery of New Warrants Upon Exercise. If this Warrant shall have been exercised in part, the Company shall, at the request of a Holder and upon surrender of this Warrant, deliver to Holder a new Warrant evidencing the rights of Holder to purchase the unpurchased Warrant Shares called for by this Warrant, which new Warrant shall in all other respects be identical with this Warrant.

iv.    Rescission Rights. If the Company fails to cause its Transfer Agent to transmit to the Holder the Warrant Shares pursuant to Section 2(g)(ii) by the Warrant Share Delivery Date, then the Holder will have the right to rescind such exercise.

v.    Compensation for Buy-In on Failure to Timely Deliver Warrant Shares Upon Exercise. In addition to any other rights available to the Holder, if the Company fails to cause the Transfer Agent to transmit to the Holder the Warrant Shares in accordance with the provisions of Section 2(g)(ii) above pursuant to an exercise on or before the Warrant Share Delivery Date, and if after such date the Holder is required by its broker to purchase and does purchase (in an open market transaction or otherwise) or the Holder’s brokerage firm otherwise purchases on the Holder’s behalf, shares of Common Stock to deliver in satisfaction of a sale by the Holder of the Warrant Shares which the Holder anticipated receiving upon such exercise (a “Buy-In”), then the Company shall (A) pay in cash to the Holder the amount, if any, by which (x) the Holder’s total purchase price (including brokerage commissions, if any) for the shares of Common Stock so purchased exceeds (y) the amount obtained by multiplying (1) the number of Warrant Shares that the Company was required to deliver to the Holder in connection with the exercise at issue and (2) the VWAP on the date of delivery of the Exercise Notice, and (B) at the option of the Holder, either reinstate the portion of the Warrant and equivalent number of Warrant Shares for which such exercise was not honored (in which case such exercise shall be deemed rescinded) or deliver to the Holder the number of shares of Common Stock that would have been issued had the Company timely complied with its exercise and delivery obligations hereunder. The Holder shall provide the Company written notice indicating the amounts payable to the Holder in respect of the Buy-In. Nothing herein shall limit a ▇▇▇▇▇▇’s right to pursue any other remedies available to it hereunder, at law or in equity including, without limitation, a decree of specific performance and/or injunctive relief with respect to the Company’s failure to timely deliver shares of Common Stock upon exercise of the Warrant as required pursuant to the terms hereof.

vi.    No Fractional Shares or Scrip. No fractional shares or scrip representing fractional shares shall be issued upon the exercise of this Warrant. As to any fraction of a share that Holder would otherwise be entitled to purchase upon such exercise, the Company shall pay a cash adjustment in respect of such final fraction in an amount equal to such fraction multiplied by the Exercise Price.

vii.    Charges, Taxes and Expenses. The issuance of Warrant Shares shall be made without charge to the Holder for any issue or transfer tax or other incidental expense in respect of such issuance, all of which taxes and expenses shall be paid by the Company, and the Company shall pay all applicable transfer agent fees and fees to the Depository Trust Company (or another established clearing corporation performing similar functions) as may be required for same day processing. The Warrant Shares shall be issued in the name of the Holder or in such name or names as may be directed by the Holder; provided,

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however, that in the event that Warrant Shares are to be issued in a name other than the name of the Holder, this Warrant when surrendered for exercise shall be accompanied by the Assignment Form attached hereto duly executed by the Holder; and the Company may require, as a condition thereto, the payment of a sum sufficient to reimburse it for any transfer tax incidental thereto.

h)    Obligations of the Company. The Company’s obligations to issue and deliver Warrant Shares in accordance with the terms hereof are absolute and unconditional, irrespective of any action or inaction by the Holder to enforce the same, any waiver or consent with respect to any provision hereof, the recovery of any judgment against any Person or any action to enforce the same, or any setoff, counterclaim, recoupment, limitation or termination, or any breach or alleged breach by the Holder or any other Person of any obligation to the Company or any violation or alleged violation of law by the Holder or any other Person, and irrespective of any other circumstance which might otherwise limit such obligation of the Company to the Holder in connection with the issuance of Warrant Shares. Nothing herein shall limit a Holder’s right to pursue any other remedies available to it hereunder, at law or in equity including, without limitation, a decree of specific performance and/or injunctive relief with respect to the Company’s failure to timely deliver the Warrant Shares upon exercise of the Warrant as required pursuant to the terms hereof.

Section 3.    Certain Adjustments.

a)    Stock Dividends and Splits. If the Company, at any time while this Warrant is outstanding: (A) pays a stock dividend or otherwise makes a distribution or distributions on shares of its Common Stock or any other equity or equity equivalent securities payable in shares of Common Stock (which, for avoidance of doubt, shall not include any shares of Common Stock issued by the Company pursuant to this Warrant), (B) subdivides outstanding shares of Common Stock into a larger number of shares, (C) combines (including by way of reverse stock split) outstanding shares of Common Stock into a smaller number of shares, or (D) issues by reclassification of shares of the Common Stock any shares of capital stock of the Company, then in each case the Exercise Price shall be multiplied by a fraction, of which the numerator shall be the number of shares of Common Stock (excluding treasury shares, if any) outstanding immediately before such event and of which the denominator shall be the number of shares of Common Stock outstanding immediately after such event and the number of shares issuable upon exercise of this Warrant shall be proportionately adjusted in an inverse manner (e.g., an increase in the Exercise Price shall result in a decrease in the number of shares of Common Stock). Any adjustment made pursuant to this Section 3(a) shall become effective immediately after the record date for the determination of stockholders entitled to receive such dividend or distribution and shall become effective immediately after the effective date in the case of a subdivision, combination or re-classification.

b)    Pro Rata Distributions. If the Company, at any time prior to the Expiry Time, shall declare, or distribute any dividend or other distribution to all holders of Common Stock (and not to Holders of the Warrants) of assets or evidence of its indebtedness (including cash and cash dividends) or rights or warrants to subscribe for or purchase any security other than the Common Stock, then in each such case the Exercise Price shall be adjusted by multiplying the Exercise Price in effect immediately prior to the record date fixed for determination of stockholders entitled to receive such distribution by a fraction, of which the

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denominator shall be the VWAP determined as of the record date mentioned above, and of which the numerator shall be such VWAP on such record date less the then per share fair market value at such record date of the portion of such assets or evidence of indebtedness so distributed applicable to one outstanding share of the Common Stock as determined by the Board of Directors of the Company in good faith. The adjustment shall be described in a statement provided to the Holder. Such adjustment shall be made whenever any such distribution is made and shall become effective immediately after the record date mentioned above.

c)    Fundamental Transaction. If, at any time while this Warrant is outstanding, (i) the Company, directly or indirectly, in one or more related transactions effects any merger or consolidation of the Company with or into another Person, (ii) the Company, directly or indirectly, effects any sale, lease, license, assignment, transfer, conveyance or other disposition of all or substantially all of its assets in one or a series of related transactions, (iii) any, direct or indirect, purchase offer, tender offer or exchange offer (whether by the Company or another Person) is completed pursuant to which holders of Common Stock are permitted to sell, tender or exchange their shares for other securities, cash or property and such offer has been accepted by the holders of a majority of the outstanding Common Stock, (iv) the Company, directly or indirectly, in one or more related transactions effects any reclassification, reorganization or recapitalization of the Common Stock or any compulsory share exchange pursuant to which the Common Stock is effectively converted into or exchanged for other securities, cash or property, or (v) the Company, directly or indirectly, in one or more related transactions consummates a stock or share purchase agreement or other business combination (including, without limitation, a reorganization, recapitalization, spin-off or scheme of arrangement) with another Person or group of Persons whereby such other Person or group acquires more than 50% of the outstanding shares of Common Stock (not including any shares of Common Stock held by the other Person or other Persons making or party to, or associated or affiliated with the other Persons making or party to, such stock or share purchase agreement or other business combination) (each a “Fundamental Transaction”), then, upon any subsequent exercise of this Warrant, the Holder shall have the right to receive, for each Warrant Share that would have been issuable upon such exercise immediately prior to the occurrence of such Fundamental Transaction, the number of shares of common stock or other equity securities of the successor or acquiring corporation or of the Company, if it is the surviving corporation, and any other or additional consideration (the “Alternate Consideration”) receivable as a result of such Fundamental Transaction by a holder of the number of shares of Common Stock for which this Warrant is then exercisable immediately prior to such Fundamental Transaction (without regard to any limitation in Section 2(d) or 2(e) on the exercise of this Warrant, which shall cease to be applicable at the time of and following the Fundamental Transaction). For purposes of any such exercise, the determination of the Exercise Price shall be appropriately adjusted to apply to such Alternate Consideration based on the amount of Alternate Consideration issuable in respect of one share of Common Stock in such Fundamental Transaction, and the Company shall apportion the Exercise Price among the Alternate Consideration in a reasonable manner reflecting the relative value of any different components of the Alternate Consideration. If holders of Common Stock are given any choice as to the securities, cash or property to be received in a Fundamental Transaction, then the Holder shall be given the same choice as to the Alternate Consideration it receives upon any exercise of this Warrant following such Fundamental Transaction. Notwithstanding the foregoing, in the event the Alternative Consideration consists solely of cash (a “Fundamental Cash Transaction”), then Holder shall exercise its conversion or

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purchase right under this Warrant and such exercise will be deemed effective immediately prior to the consummation of such Fundamental Cash Transaction. If Holder does not so exercise this Warrant, this Warrant shall automatically be exercised pursuant to Section 2(c) hereof, without any action by Holder and without regard to any ownership limitation in Section 2(d) or 2(e) immediately prior to the consummation of such Fundamental Cash Transaction and in such event Holder shall not be required to pay the exercise price for the shares of Common Stock and may in the alternative elect to receive the cash consideration upon consummation, less the exercise price for the shares of Common Stock for which this Warrant has been exercised. The Company shall provide the Holder with written notice of the Fundamental Cash Transaction (together with such reasonable information as the Holder may request in connection with such contemplated Acquisition giving rise to such notice), which is to be delivered to Holder not less than ten (10) days prior to the closing of the proposed Fundamental Cash Transaction. To the extent necessary to effectuate the foregoing provisions, any successor to the Company or surviving entity in such Fundamental Transaction shall issue to the Holder a new warrant consistent with the foregoing provisions and evidencing the Holder’s right to exercise such warrant for the Alternate Consideration. The terms of any agreement pursuant to which a Fundamental Transaction is effected shall include terms requiring any such successor or surviving entity to comply with the provisions of this Section 3(c) and insuring that this Warrant (or any such replacement security) will be similarly adjusted upon any subsequent transaction analogous to a Fundamental Transaction.

d)    Calculations. All calculations under this Section 3 shall be made to the nearest cent or the nearest 1/100th of a share, as the case may be. For purposes of this Section 3, the number of shares of Common Stock deemed to be issued and outstanding as of a given date shall be the sum of the number of shares of Common Stock (excluding treasury shares, if any) issued and outstanding.

e)    Notice to Holders.

i.    Adjustment to Exercise Price. Whenever the Exercise Price is adjusted pursuant to this Section 3, the Company shall promptly deliver to each Holder a notice setting forth the Exercise Price after such adjustment and setting forth a brief statement of the facts requiring such adjustment.

ii.    Notice to Allow Exercise by ▇▇▇▇▇▇. If (A) the Company shall declare a dividend (or any other distribution) on the Common Stock; (B) the Company shall declare a special nonrecurring cash dividend on or a redemption of the Common Stock; (C) the Company shall authorize the granting to all holders of the Common Stock rights or warrants to subscribe for or purchase any shares of capital stock of any class or of any rights; (D) the approval of any stockholders of the Company shall be required in connection with any Fundamental Transaction; (E) the Company shall authorize the voluntary or involuntary dissolution, liquidation or winding up of the affairs of the Company; then, in each case, the Company shall cause to be delivered by facsimile or email to the Holder at its last address as it shall appear upon the Warrant Register of the Company, at least ten (10) calendar days prior to the applicable record or effective date hereinafter specified, a notice stating (x) the date on which a record is to be taken for the purpose of such dividend, distribution, redemption, rights or warrants, or if a record is not to be taken, the date as of which the holders of the Common Stock

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of record to be entitled to such dividend, distributions, redemption, rights or warrants are to be determined or (y) the date on which such reclassification, consolidation, merger, sale, transfer or share exchange is expected to become effective or close, and the date as of which it is expected that holders of the Common Stock of record shall be entitled to exchange their shares of the Common Stock for securities, cash or other property deliverable upon such reclassification, consolidation, merger, sale, transfer or share exchange; provided, that the failure to deliver such notice or any defect therein or in the delivery thereof shall not affect the validity of the corporate action required to be specified in such notice. The Holder is entitled to exercise this Warrant during the ten (10)-day period commencing on the date of such notice to the effective date of the event triggering such notice. To the extent that any notice provided in this Warrant constitutes, or contains, material non-public information regarding the Company, the Company shall make such information known to the public through a press release, filing with the Securities and Exchange Commission, or other public announcement prior to or in conjunction with such notice being provided to the Holder.

Section 4.    Transfer of Warrant.

a)    Transferability. Subject to compliance with any applicable securities laws and to the provisions of Section 7.5 of the Purchase Agreement, this Warrant and all rights hereunder are transferable, in whole or in part, upon surrender of this Warrant at the principal office of the Company or its designated agent, together with a written assignment of this Warrant substantially in the form attached hereto duly executed by the Holder or its agent or attorney and funds sufficient to pay any transfer taxes payable upon the making of such transfer. Upon such surrender and, if required, such payment, the Company shall execute and deliver a new Warrant or Warrants in the name of the assignee or assignees, as applicable, and in the denomination or denominations specified in such instrument of assignment, and shall issue to the assignor a new Warrant evidencing the portion of this Warrant not so assigned, and this Warrant shall promptly be cancelled. This Warrant, if properly assigned in accordance herewith, may be exercised by a new holder for the purchase of Warrant Shares without having a new Warrant issued. The Holder represents that by accepting this Warrant it understands that this Warrant and any securities obtainable upon exercise of this Warrant have not been registered for sale under Federal or state securities laws and are being offered and sold to the Holder pursuant to one or more exemptions from the registration requirements of such securities laws. The Holder understands that it must bear the economic risk of its investment in this Warrant and any securities obtainable upon exercise of this Warrant for an indefinite period of time, as this Warrant and such securities have not been registered under Federal or state securities laws and therefore cannot be sold unless subsequently registered under such laws, unless an exemption from such registration is available.

b)    New Warrants. This Warrant may be divided or combined with other Warrants upon presentation hereof at the aforesaid office of the Company, together with a written notice specifying the names and denominations in which new Warrants are to be issued, signed by the Holder or its agent or attorney. Subject to compliance with Section 4(a), as to any transfer which may be involved in such division or combination, the Company shall execute and deliver a new Warrant or Warrants or like tenor in exchange for the Warrant or Warrants to be divided or combined in accordance with such notice.

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c)    Warrant Register. The Company shall register this Warrant, upon records to be maintained by the Company for that purpose (the “Warrant Register”), in the name of the record Holder hereof. The Company may deem and treat the registered Holder of this Warrant as the absolute owner hereof for the purpose of any exercise hereof or any distribution to the Holder, and for all other purposes, absent actual notice to the contrary.

Section 5.    Miscellaneous.

a)    No Rights as Stockholder Until Exercise. This Warrant does not entitle the Holder to any voting rights or other rights as a stockholder of the Company prior to effectiveness of the exercise hereof.

b)    Loss, Theft, Destruction or Mutilation of Warrant. The Company covenants that upon receipt by the Company of evidence reasonably satisfactory to it of the loss, theft, destruction or mutilation of this Warrant or any stock certificate relating to the Warrant Shares, and in case of loss, theft or destruction, of indemnity or security reasonably satisfactory to it (which, in the case of the Warrant, shall not include the posting of any bond), and upon surrender and cancellation of such Warrant or stock certificate, if mutilated, the Company will make and deliver a new Warrant or stock certificate of like tenor and dated as of such cancellation, in lieu of such Warrant or stock certificate.

c)    Saturdays, Sundays, Holidays, etc. If the last or appointed day for the taking of any action or the expiration of any right required or granted herein shall be a Saturday, Sunday or a legal holiday, then such action may be taken or such right may be exercised on the next succeeding day not a Saturday, Sunday or legal holiday.

d)    Authorized Shares. The Company covenants that during the period the Warrant is outstanding, it will maintain a reserve, free from preemption rights, from its duly authorized shares of Common Stock for issuance upon exercise of this Warrant. The Company further covenants that its issuance of this Warrant shall constitute full authority to its officers who are charged with the duty of executing stock certificates or book entry shares to execute and issue the necessary certificates or book entry shares for the Warrant Shares upon the exercise of the purchase rights under this Warrant. If at any time prior to the Expiry Time the number of authorized but unissued shares of Common Stock shall not be sufficient to permit exercise of this Warrant, the Company will take such corporate action as may, in the opinion of its counsel, be necessary to increase its authorized but unissued shares of Common Stock (or other securities as provided herein) to such number of shares as shall be sufficient for such purposes.

Except and to the extent waived or consented to by the Holder, the Company hereby covenants to not, by any action, including, without limitation, amending its certificate of incorporation, by-laws or through any reorganization, transfer of assets, consolidation, merger, dissolution, issue or sale of securities or any other voluntary action, avoid or seek to avoid the observance or performance of any of the terms of this Warrant, and will at all times in good faith assist in the carrying out of all such terms and in the taking of all such actions as may be necessary or appropriate to protect the rights of Holder as set forth in this Warrant against impairment. Without limiting the generality of the foregoing, the Company will (a) not increase the par value of any Warrant Shares above the Exercise Price then in effect and (b) take all such action as may be necessary or appropriate in order that the Company may validly and legally issue fully paid and nonassessable Warrant Shares upon the exercise of this Warrant.

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e)    Jurisdiction. All questions concerning the construction, validity, enforcement and interpretation of this Warrant shall be determined in accordance with the provisions of the Securities Purchase Agreement.

f)    Restrictions. The Holder acknowledges that the Warrant Shares acquired upon the exercise of this Warrant, if not registered and if the Holder does not utilize cashless exercise after expiration of the Rule 144 holding period, will contain a legend to the effect that the Warrant Shares are not registered.

g)    Nonwaiver and Expenses. No course of dealing or any delay or failure to exercise any right hereunder on the part of Holder shall operate as a waiver of such right or otherwise prejudice Holder’s rights, powers or remedies, notwithstanding the fact that the right to exercise this Warrant terminates on the Expiry Time. If the Company willfully and knowingly fails to comply with any provision of this Warrant, which results in any material damages to the Holder, the Company shall pay to Holder such amounts as shall be sufficient to cover any costs and expenses including, but not limited to, reasonable attorney’s fees, including those of appellate proceedings, incurred by the Holder in collecting any amounts due pursuant hereto or in otherwise enforcing any of its rights, powers or remedies hereunder.

h)    Notices. Any notice, request or other document required or permitted to be given or delivered to the Holder by the Company shall be delivered in accordance with the notice provisions of the Securities Purchase Agreement.

i)    Limitation of Liability. No provision hereof, in the absence of any affirmative action by Holder to exercise this Warrant or purchase Warrant Shares, and no enumeration herein of the rights or privileges of Holder, shall give rise to any liability of Holder for the purchase price of any Common Stock or as a stockholder of the Company, whether such liability is asserted by the Company or by creditors of the Company.

j)    Remedies. The remedies provided in this Warrant shall be cumulative and in addition to all other remedies available or granted by law, including recovery of damages. Each of the parties hereto will be entitled to specific performance of its rights under this Warrant. The Company acknowledges that a breach by it of its obligations hereunder will cause irreparable harm to the Holder and agrees that monetary damages would not be adequate compensation for any loss incurred by reason of a breach or threatened breach by it of the provisions of this Warrant and hereby agrees to waive the defense in any action for specific performance that a remedy at law would be adequate including making a showing of economic loss and the posting of a bond or other security.

k)    Successors and Assigns. Subject to applicable securities laws, this Warrant and the rights and obligations evidenced hereby shall inure to the benefit of and be binding upon the successors of the Company and the successors and permitted assigns of Holder. The provisions of this Warrant are intended to be for the benefit of all Holders from time to time of this Warrant and shall be enforceable by any such Holder or holder of Warrant Shares.

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l)    Amendment. This Warrant may be modified or amended or the provisions hereof waived only with the written consent of the Company and the Holder.

m)    Severability. Wherever possible, each provision of this Warrant shall be interpreted in such manner as to be effective and valid under applicable law, but if any provision of this Warrant shall be prohibited by or invalid under applicable law, such provision shall be ineffective to the extent of such prohibition or invalidity, without invalidating the remainder of such provisions or the remaining provisions of this Warrant.

n)    Headings. The headings used in this Warrant are for the convenience of reference only and shall not, for any purpose, be deemed a part of this Warrant.

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IN WITNESS WHEREOF, the Company has caused this Warrant to be executed by its officer thereunto duly authorized.

Dated: April 2, 2019

NOTICE OF EXERCISE

TO:    AILERON THERAPEUTICS, INC.

(1)    The undersigned hereby elects to purchase                  Warrant Shares of the Company pursuant to the terms of the attached Warrant (only if exercised in full), and tenders herewith payment of the Exercise Price in full, together with all applicable transfer taxes, if any.

(2)    Payment shall take the form of (check applicable box):

(3)    Please cause the Warrant Shares to be issued in the name of the undersigned or in such other name as is specified below:

The Warrant Shares shall be delivered to the following DWAC Account Number :

(4)    Accredited Investor. The undersigned is an “accredited investor” as defined in Regulation D promulgated under the Securities Act of 1933, as amended.

Name of Investing Entity:                                                                                                                                                                

Signature of Authorized Signatory of Investing Entity:                                                                                                                 

Name of Authorized Signatory:                                                                                                                                                        

Title of Authorized Signatory:                                                                                                                                                          

Date:                                                                                                                                                                                                   

ASSIGNMENT FORM

(To assign the foregoing warrant, execute

this form and supply required information.

Do not use this form to exercise the warrant.)

FOR VALUE RECEIVED, the foregoing Warrant and all rights evidenced thereby are hereby assigned to:

whose address is:

Dated:                                 ,                             

Holder’s Signature:                                                                                                                                                           

Holder’s Address:                                                                                                                                                             

Signature Guaranteed:                                                                                                                                                       

NOTE: The signature to this Assignment Form must correspond with the name as it appears on the face of the Warrant, without alteration or enlargement or any change whatsoever, and must be guaranteed by a bank or trust company. Officers of corporations and those acting in a fiduciary or other representative capacity should file proper evidence of authority to assign the foregoing Warrant.