EX-10.4



 Exhibit 10.4 

2016 STOCK INCENTIVE PLAN 

OF 

AILERON THERAPEUTICS, INC. 







 TABLE OF CONTENTS 

 

									
	 	 	 	  	 	  	PAGE	 
	 1.
	 	 Purpose
	  	 	1	 
	 2.
	 	 Eligibility
	  	 	1	 
	 3.
	 	 Administration and Delegation
	  	 	1	 
		 	 (a)
	  	 Administration by the Board
	  	 	1	 
		 	 (b)
	  	 Appointment of Committees
	  	 	2	 
		 	 (c)
	  	 Delegation to Officers
	  	 	2	 
	 4.
	 	 Stock Available for Awards
	  	 	2	 
		 	 (a)
	  	 Number of Shares
	  	 	2	 
		 	 (b)
	  	 Substitute Awards
	  	 	3	 
	 5.
	 	 Stock Options
	  	 	3	 
		 	 (a)
	  	 General
	  	 	3	 
		 	 (b)
	  	 Incentive Stock Options
	  	 	3	 
		 	 (c)
	  	 Exercise Price
	  	 	3	 
		 	 (d)
	  	 Duration of Options
	  	 	4	 
		 	 (e)
	  	 Exercise of Options
	  	 	4	 
		 	 (f)
	  	 Payment Upon Exercise
	  	 	4	 
	 6.
	 	 Stock Appreciation Rights
	  	 	5	 
		 	 (a)
	  	 General
	  	 	5	 
		 	 (b)
	  	 Measurement Price
	  	 	5	 
		 	 (c)
	  	 Duration of SARs
	  	 	5	 
		 	 (d)
	  	 Exercise of SARs
	  	 	5	 
	 7.
	 	 Restricted Stock; Restricted Stock Units
	  	 	5	 
		 	 (a)
	  	 General
	  	 	5	 
		 	 (b)
	  	 Terms and Conditions for All Restricted Stock Awards
	  	 	6	 
		 	 (c)
	  	 Additional Provisions Relating to Restricted Stock
	  	 	6	 
		 	 (d)
	  	 Additional Provisions Relating to Restricted Stock Units
	  	 	6	 
	 8.
	 	 Other Stock-Based Awards
	  	 	7	 
		 	 (a)
	  	 General
	  	 	7	 
		 	 (b)
	  	 Terms and Conditions
	  	 	7	 
	 9.
	 	 Adjustments for Changes in Common Stock and Certain Other Events
	  	 	7	 
		 	 (a)
	  	 Changes in Capitalization
	  	 	7	 
		 	 (b)
	  	 Reorganization Events
	  	 	8	 
	 10.
	 	 General Provisions Applicable to Awards
	  	 	9	 
		 	 (a)
	  	 Transferability of Awards
	  	 	9	 
		 	 (b)
	  	 Documentation
	  	 	10	 
		 	 (c)
	  	 Board Discretion
	  	 	10	 
		 	 (d)
	  	 Termination of Status
	  	 	10	 
		 	 (e)
	  	 Withholding
	  	 	10	 
		 	 (f)
	  	 Amendment of Award
	  	 	11	 
		 	 (g)
	  	 Conditions on Delivery of Stock
	  	 	11	 
		 	 (h)
	  	 Acceleration
	  	 	11	 









									
	 11.
	 	 Miscellaneous
	  	 	12	 
		 	 (a)
	  	 No Right To Employment or Other Status
	  	 	12	 
		 	 (b)
	  	 No Rights As Stockholder
	  	 	12	 
		 	 (c)
	  	 Effective Date and Term of Plan
	  	 	12	 
		 	 (d)
	  	 Amendment of Plan
	  	 	12	 
		 	 (e)
	  	 Authorization of Sub-Plans (including Grants to non-U.S. Employees)
	  	 	12	 
		 	 (f)
	  	 Compliance with Section 409A of the Code
	  	 	12	 
		 	 (g)
	  	 Limitations on Liability
	  	 	13	 
		 	 (h)
	  	 Governing Law
	  	 	13	 


  
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 2016 STOCK INCENTIVE PLAN 

OF 

AILERON THERAPEUTICS, INC. 

 

	1.	Purpose 

 The purpose of this 2016 Stock Incentive Plan (the “Plan”) of
Aileron Therapeutics, Inc., a Delaware corporation (the “Company”), is to advance the interests of the Company’s stockholders by enhancing the Company’s ability to attract, retain and motivate persons who are
expected to make important contributions to the Company and by providing such persons with equity ownership opportunities and performance-based incentives that are intended to better align the interests of such persons with those of the
Company’s stockholders. Except where the context otherwise requires, the term “Company” shall include any of the Company’s present and future parent or subsidiary corporations as defined in Sections 424(e) or
(f) of the Internal Revenue Code of 1986, as amended, and any regulations thereunder (the “Code”) and any other business venture (including, without limitation, joint venture or limited liability company) in which the Company
has a controlling interest, as determined by the Board of Directors of the Company (the “Board”); provided, however, that such other business ventures shall be limited to entities that, where required by Section 409A
of the Code, are eligible issuers of service recipient stock (as defined in Treas. Reg. Section 1.409A-1(b)(5)(iii)(E), or applicable successor regulation). 

 

	2.	Eligibility 

 All of the Company’s employees, officers and directors, as well as
consultants and advisors to the Company (as such terms consultants and advisors are defined and interpreted for purposes of Rule 701 under the Securities Act of 1933, as amended (the “Securities Act”) (or any successor rule)) are
eligible to be granted Awards under the Plan. Each person who is granted an Award under the Plan is deemed a “Participant.” “Award” means Options (as defined in Section 5), SARs (as defined in Section 6),
Restricted Stock (as defined in Section 7), Restricted Stock Units (as defined in Section 7) and Other Stock-Based Awards (as defined in Section 8). 
  

	3.	Administration and Delegation 

 (a)    Administration by the
Board. The Plan will be administered by the Board. The Board shall have authority to grant Awards and to adopt, amend and repeal such administrative rules, guidelines and practices relating to the Plan as it shall deem advisable. The Board may
construe and interpret the terms of the Plan and any Award agreements entered into under the Plan. The Board may correct any defect, supply any omission or reconcile any inconsistency in the Plan or any Award in the manner and to the extent it shall
deem expedient to carry the Plan into effect and it shall be the sole and final judge of such expediency. All actions and decisions by the Board with respect to the Plan and any Awards shall be made in the Board’s discretion and shall be final
and binding on all Participants and any other persons having or claiming any interest in the Plan or in any Award. 







 (b)    Appointment of Committees. To the extent permitted by
applicable law, the Board may delegate any or all of its powers under the Plan to one or more committees or subcommittees of the Board (each, a “Committee”). All references in the Plan to the “Board” shall mean the
Board or a Committee or the officers referred to in Section 3(c) to the extent that the Board’s powers or authority under the Plan have been delegated to such Committee or officers. 

(c)    Delegation to Officers. Subject to any requirements of applicable law (including as applicable Sections 152
and 157(c) of the General Corporation Law of the State of Delaware), the Board may delegate to one or more officers of the Company the power to grant Awards (subject to any limitations under the Plan) to employees or officers of the Company and to
exercise such other powers under the Plan as the Board may determine, provided that the Board shall fix the terms of Awards to be granted by such officers, the maximum number of shares subject to Awards that the officers may grant, and the time
period in which such Awards may be granted; and provided further, that no officer shall be authorized to grant Awards to any “executive officer” of the Company (as defined by Rule 3b-7 under the
Securities Exchange Act of 1934, as amended (the “Exchange Act”)) or to any “officer” of the Company (as defined by Rule 16a-1(f) under the Exchange Act). 

 

	4.	Stock Available for Awards 

 (a)    Number of Shares. Subject
to adjustment under Section 9, Awards may be made under the Plan for up to such number of shares of common stock, $0.001 par value per share, of the Company (the “Common Stock”) as is equal to the sum of: 

(1)    7,583,595 shares of Common Stock; plus 

(2)    such additional number of shares of Common Stock (up to 9,757,648 shares) as is equal to the number of shares of
Common Stock subject to awards granted under the Company’s 2006 Stock Incentive Plan which awards expire, terminate or are otherwise surrendered, canceled, forfeited or repurchased by the Company at their original issuance price pursuant to a
contractual repurchase right (subject, however, in the case of Incentive Stock Options to any limitations of the Code). 
 Any or all Awards
may be in the form of Incentive Stock Options (as defined in Section 5(b)). If any Award expires or is terminated, surrendered or canceled without having been fully exercised, is forfeited in whole or in part (including as the result of shares of
Common Stock subject to such Award being repurchased by the Company at the original issuance price pursuant to a contractual repurchase right), or results in any Common Stock not being issued, the unused Common Stock subject to such Award shall
again be available for the grant of Awards under the Plan. Further, shares of Common Stock tendered to the Company by a Participant to exercise an Award or to satisfy tax withholding obligations arising with respect to an Award shall be added to the
number of shares of Common Stock available for the grant of Awards under the Plan. However, in the case of Incentive Stock Options, the two immediately preceding sentences shall be subject to any limitations under the Code. Shares issued under the
Plan may consist in whole or in part of authorized but unissued shares or treasury shares. 

  
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 (b)    Substitute Awards. In connection with a merger or consolidation
of an entity with the Company or the acquisition by the Company of property or stock of an entity, the Board may grant Awards in substitution for any options or other stock or stock-based awards granted by such entity or an affiliate thereof.
Substitute Awards may be granted on such terms as the Board deems appropriate in the circumstances, notwithstanding any limitations on Awards contained in the Plan. Substitute Awards shall not count against the overall share limit set forth in
Section 4(a), except as may be required by reason of Section 422 and related provisions of the Code. 
  

	5.	Stock Options 

 (a)    General. The Board may grant options to
purchase Common Stock (each, an “Option”) and determine the number of shares of Common Stock to be subject to each Option, the exercise price of each Option and the conditions and limitations applicable to the exercise of each
Option, including conditions relating to applicable federal or state securities laws, as it considers necessary or advisable. 

(b)    Incentive Stock Options. An Option that the Board intends to be an “incentive stock option” as
defined in Section 422 of the Code (an “Incentive Stock Option”) shall only be granted to employees of Aileron Therapeutics, Inc., any of Aileron Therapeutics, Inc.’s present and future parent or subsidiary corporations as
defined in Sections 424(e) or (f) of the Code, and any other entities the employees of which are eligible to receive Incentive Stock Options under the Code, and shall be subject to and shall be construed consistently with the requirements of
Section 422 of the Code. An Option that is not intended to be an Incentive Stock Option shall be designated non-statutory stock option (a “Nonstatutory Stock Option).” The Company shall have no liability to a
Participant, or any other person, if an Option (or any part thereof) that is intended to be an Incentive Stock Option is not an Incentive Stock Option or if the Company converts an Incentive Stock Option to a Nonstatutory Stock Option. 

(c)    Exercise Price. The Board shall establish the exercise price of each Option and specify the exercise price
in the applicable Option agreement. The exercise price shall be not less than 100% of the Grant Date Fair Market Value (as defined below) of the Common Stock on the date the Option is granted; provided that if the Board approves the grant of an
Option with an exercise price to be determined on a future date, the exercise price shall not be less than 100% of the Grant Date Fair Market Value on such future date. The “Grant Date Fair Market Value” of a share of Common
Stock for purposes of the Plan will be determined as follows: 
 (1)    if the Common Stock is not publicly traded, the
Board will determine the Fair Market Value for purposes of the Plan using any measure of value it determines to be appropriate (including, as it considers appropriate, relying on appraisals) in a manner consistent with the valuation principles under
Code Section 409A, except as the Board may expressly determine otherwise; 
 (2)    if the Common Stock is listed on a
national securities exchange, the closing sale price (for the primary trading session) on the date of grant; or 

  
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 (3)    if the Common Stock is not listed on any such exchange, the average of
the closing bid and asked prices as reported by an authorized OTCBB market data vendor as listed on the OTCBB website (otcbb.com) on the date of grant. 

For any date that is not a trading day, the Grant Date Fair Market Value of a share of Common Stock for such date will be determined by using
the closing sale price or average of the bid and asked prices, as appropriate, for the immediately preceding trading day and with the timing in the formulas above adjusted accordingly. The Board can substitute a particular time of day or other
measure of “closing sale price” or “bid and asked prices” if appropriate because of exchange or market procedures or can, in its discretion, use weighted averages either on a daily basis or such longer period as complies with
Code Section 409A. 
 The Board has discretion to determine the Grant Date Fair Market Value for purposes of the Plan, and all Awards are
conditioned on the applicable Participant’s agreement that the Board’s determination is conclusive and binding even though others might make a different determination. 

(d)    Duration of Options. Each Option shall be exercisable at such times and subject to such terms and conditions
as the Board may specify in the applicable option agreement; provided, however, that no Option will be granted with a term in excess of 10 years. 

(e)    Exercise of Options. Options may be exercised by delivery to the Company of a notice of exercise in a form
of notice (which may be electronic) approved by the Company, together with payment in full (in the manner specified in Section 5(f)) of the exercise price for the number of shares for which the Option is exercised. Shares of Common Stock subject to
the Option will be delivered by the Company as soon as practicable following exercise. 
 (f)    Payment
Upon Exercise. Common Stock purchased upon the exercise of an Option granted under the Plan shall be paid for as follows: 

(1)    in cash or by check, payable to the order of the Company; 

(2)    when the Common Stock is registered under the Exchange Act, except as may otherwise be provided in the applicable
Option agreement or approved by the Board, in its discretion, by (i) delivery of an irrevocable and unconditional undertaking by a creditworthy broker to deliver promptly to the Company sufficient funds to pay the exercise price and any
required tax withholding or (ii) delivery by the Participant to the Company of a copy of irrevocable and unconditional instructions to a creditworthy broker to deliver promptly to the Company cash or a check sufficient to pay the exercise price
and any required tax withholding; 
 (3)    when the Common Stock is registered under the Exchange Act and to the extent
provided for in the applicable Option agreement or approved by the Board, in its discretion, by delivery (either by actual delivery or attestation) of shares of Common Stock owned by the Participant valued at their fair market value (valued in the
manner determined by (or in a manner approved by) the Board), provided (i) such method of payment is then permitted under applicable law, (ii) such Common Stock, if acquired directly from the Company, was owned by the Participant
for such minimum period of time, if any, as may be established by the Board in its discretion and (iii) such Common Stock is not subject to any repurchase, forfeiture, unfulfilled vesting or other similar requirements; 

  
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 (4)    to the extent provided for in the applicable Nonstatutory Stock Option
agreement or approved by the Board in its discretion, by delivery of a notice of “net exercise” to the Company, as a result of which the Participant would receive (i) the number of shares underlying the portion of the Option being
exercised, less (ii) such number of shares as is equal to (A) the aggregate exercise price for the portion of the Option being exercised divided by (B) the fair market value of the Common Stock (valued in the manner determined by (or
in a manner approved by) the Board) on the date of exercise; 
 (5)    to the extent permitted by applicable law and
provided for in the applicable Option agreement or approved by the Board, in its discretion, by (i) delivery of a promissory note of the Participant to the Company on terms determined by the Board, or (ii) payment of such other lawful
consideration as the Board may determine; or 
 (6)    by any combination of the above permitted forms of payment. 

 

	6.	Stock Appreciation Rights 

 (a)    General. The Board may
grant Awards consisting of stock appreciation rights (“SARs”) entitling the Participant, upon exercise, to receive an amount of Common Stock or cash or a combination thereof (such form to be determined by the Board) determined by
reference to appreciation, from and after the date of grant, in the fair market value of a share of Common Stock (valued in the manner determined by (or in a manner approved by) the Board) over the measurement price established pursuant to Section
6(b). The date as of which such appreciation is determined shall be the exercise date. 
 (b)    Measurement
Price. The Board shall establish the measurement price of each SAR and specify it in the applicable SAR agreement. The measurement price shall not be less than 100% of the Grant Date Fair Market Value of a share of Common Stock on the date the
SAR is granted; provided, that if the Board approves the grant of an SAR effective as of a future date, the measurement price shall not be less than 100% of the Grant Date Fair Market Value on such future date. 

(c)    Duration of SARs. Each SAR shall be exercisable at such times and subject to such terms and conditions as
the Board may specify in the applicable SAR agreement; provided, however, that no SAR will be granted with a term in excess of 10 years. 

(d)    Exercise of SARs. SARs may be exercised by delivery to the Company of a notice of exercise in a form (which
may be electronic) approved by the Company, together with any other documents required by the Board. 
  

	7.	Restricted Stock; Restricted Stock Units 

 (a)    General. The
Board may grant Awards entitling Participants to acquire shares of Common Stock (“Restricted Stock”), subject to the right of the Company to repurchase all or part of such shares at their issue price or other stated or formula price
(or to require forfeiture of 

  
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such shares if issued at no cost) from the Participant in the event that conditions specified by the Board in the applicable Award are not satisfied prior to the end of the applicable restriction
period or periods established by the Board for such Award. The Board may also grant Awards entitling the Participant to receive shares of Common Stock or cash to be delivered at the time such Award vests (“Restricted Stock Units”)
(Restricted Stock and Restricted Stock Units are each referred to herein as a “Restricted Stock Award”). 

(b)    Terms and Conditions for All Restricted Stock Awards. The Board shall determine the terms and conditions of
a Restricted Stock Award, including the conditions for vesting and repurchase (or forfeiture) and the issue price, if any. 

(c)    Additional Provisions Relating to Restricted Stock. 

(1)    Dividends. Unless otherwise provided in the applicable Award agreement, any dividends (whether paid in cash,
stock or property) declared and paid by the Company with respect to shares of Restricted Stock (“Accrued Dividends”) shall be paid to the Participant only if and when such shares become free from the restrictions on transferability
and forfeitability that apply to such shares. Each payment of Accrued Dividends will be made no later than the end of the calendar year in which the dividends are paid to stockholders of that class of stock or, if later, the 15th day of the third
month following the lapsing of the restrictions on transferability and the forfeitability provisions applicable to the underlying shares of Restricted Stock. 

(2)    Stock Certificates. The Company may require that any stock certificates issued in respect of shares of
Restricted Stock, as well as dividends or distributions paid on such Restricted Stock, shall be deposited in escrow by the Participant, together with a stock power endorsed in blank, with the Company (or its designee). At the expiration of the
applicable restriction periods, the Company (or such designee) shall deliver the certificates no longer subject to such restrictions to the Participant or if the Participant has died, to Participant’s Designated Beneficiary. “Designated
Beneficiary” means (i) the beneficiary designated, in a manner determined by the Board, by a Participant to receive amounts due or exercise rights of the Participant in the event of the Participant’s death or (ii) in the
absence of an effective designation by a Participant, “Designated Beneficiary” means the Participant’s estate. 

(d)    Additional Provisions Relating to Restricted Stock Units. 

(1)    Settlement. Upon the vesting of and/or lapsing of any other restrictions (i.e., settlement) with respect to
each Restricted Stock Unit, the Participant shall be entitled to receive from the Company the number of shares of Common Stock specified in the Award agreement or (if so provided in the applicable Award agreement or otherwise determined by the
Board) an amount of cash equal to the fair market value (valued in the manner determined by (or in a manner approved by) the Board) of such number of shares of Common Stock or a combination thereof. The Board may, in its discretion, provide that
settlement of Restricted Stock Units shall be deferred, on a mandatory basis or at the election of the Participant in a manner that complies with Section 409A of the Code. 

  
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 (2)    Voting Rights. A Participant shall have no voting rights with
respect to any Restricted Stock Units. 
 (3)    Dividend Equivalents. The Award agreement for Restricted Stock
Units may provide Participants with the right to receive an amount equal to any dividends or other distributions declared and paid on an equal number of outstanding shares of Common Stock (“Dividend Equivalents”). Dividend
Equivalents may be paid currently or credited to an account for the Participants, may be settled in cash and/or shares of Common Stock and may be subject to the same restrictions on transfer and forfeitability as the Restricted Stock Units with
respect to which paid, in each case to the extent provided in the applicable Award agreement. 
  

	8.	Other Stock-Based Awards 

 (a)    General. The Board may grant
other Awards of shares of Common Stock, and other Awards that are valued in whole or in part by reference to, or are otherwise based on, shares of Common Stock or other property (“Other Stock-Based Awards”). Such Other Stock-Based
Awards shall also be available as a form of payment in the settlement of other Awards granted under the Plan or as payment in lieu of compensation to which a Participant is otherwise entitled. Other Stock-Based Awards may be paid in shares of Common
Stock or cash, as the Board shall determine. 
 (b)    Terms and Conditions. Subject to the provisions of the
Plan, the Board shall determine the terms and conditions of each Other Stock-Based Award, including any purchase price applicable thereto. 
  

	9.	Adjustments for Changes in Common Stock and Certain Other Events 


(a)    Changes in Capitalization. In the event of any stock split, reverse stock split, stock dividend,
recapitalization, combination of shares, reclassification of shares, spin-off or other similar change in capitalization or event, or any dividend or distribution to holders of Common Stock other than an
ordinary cash dividend, (i) the number and class of securities available under the Plan, (ii) the number and class of securities and exercise price per share of each outstanding Option, (iii) the share and per-share provisions and the measurement price of each outstanding SAR, (iv) the number of shares subject to and the repurchase price per share subject to each outstanding Award of Restricted Stock and
(v) the share and per-share-related provisions and the purchase price, if any, of each outstanding Award of Restricted Stock Unit and each outstanding Other Stock-Based Award, shall be equitably adjusted
by the Company (or substituted Awards may be made, if applicable) in the manner determined by the Board. Without limiting the generality of the foregoing, in the event the Company effects a split of the Common Stock by means of a stock dividend and
the exercise price of and the number of shares subject to an outstanding Option are adjusted as of the date of the distribution of the dividend (rather than as of the record date for such dividend), then an optionee who exercises an Option between
the record date and the distribution date for such stock dividend shall be entitled to receive, on the distribution date, the stock dividend with respect to the shares of Common Stock acquired upon such Option exercise, notwithstanding the fact that
such shares were not outstanding as of the close of business on the record date for such stock dividend. 

  
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 (b)    Reorganization Events. 

(1)    Definition. A “Reorganization Event” shall mean: (a) any merger or consolidation of the
Company with or into another entity as a result of which all of the Common Stock of the Company is converted into or exchanged for the right to receive cash, securities or other property or is cancelled, (b) any transfer or disposition of all
of the Common Stock of the Company for cash, securities or other property pursuant to a share exchange or other transaction or (c) any liquidation or dissolution of the Company. 

(2)    Consequences of a Reorganization Event on Awards Other than Restricted Stock. 

(i)    In connection with a Reorganization Event, the Board may take any one or more of the following actions as to all or
any (or any portion of) outstanding Awards other than Restricted Stock on such terms as the Board determines (except to the extent specifically provided otherwise in an applicable Award agreement or another agreement between the Company and the
Participant): (i) provide that such Awards shall be assumed, or substantially equivalent Awards shall be substituted, by the acquiring or succeeding corporation (or an affiliate thereof), (ii) upon written notice to a Participant, provide
that all of the Participant’s unexercised and/or unvested Awards will terminate immediately prior to the consummation of such Reorganization Event unless exercised by the Participant (to the extent then exercisable) within a specified period
following the date of such notice, (iii) provide that outstanding Awards shall become exercisable, realizable, or deliverable, or restrictions applicable to an Award shall lapse, in whole or in part prior to or upon such Reorganization Event,
(iv) in the event of a Reorganization Event under the terms of which holders of Common Stock will receive upon consummation thereof a cash payment for each share surrendered in the Reorganization Event (the “Acquisition
Price”), make or provide for a cash payment to Participants with respect to each Award held by a Participant equal to (A) the number of shares of Common Stock subject to the vested portion of the Award (after giving effect to any
acceleration of vesting that occurs upon or immediately prior to such Reorganization Event) multiplied by (B) the excess, if any, of (I) the Acquisition Price over (II) the exercise, measurement or purchase price of such Award and any
applicable tax withholdings, in exchange for the termination of such Award, (v) provide that, in connection with a liquidation or dissolution of the Company, Awards shall convert into the right to receive liquidation proceeds (if applicable,
net of the exercise, measurement or purchase price thereof and any applicable tax withholdings) and (vi) any combination of the foregoing. In taking any of the actions permitted under this Section 9(b)(2), the Board shall not be obligated by
the Plan to treat all Awards, all Awards held by a Participant, or all Awards of the same type, identically. 

(ii)    Notwithstanding the terms of Section 9(b)(2)(i), in the case of outstanding Restricted Stock Units that are
subject to Section 409A of the Code: (i) if the applicable Restricted Stock Unit agreement provides that the Restricted Stock Units shall be settled upon a “change in control event” within the meaning of Treasury Regulation Section 1.409A-3(i)(5)(i), and the Reorganization Event constitutes such a “change in control event”, then no assumption or substitution shall be permitted pursuant to Section 9(b)(2)(i) and the Restricted Stock
Units shall instead be settled in accordance with the terms of the applicable Restricted Stock Unit agreement; and (ii) the Board may only undertake the actions set forth in 

  
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clauses (iii), (iv) or (v) of Section 9(b)(2)(i) if the Reorganization Event constitutes a “change in control event” as defined under Treasury Regulation Section 1.409A-3(i)(5)(i) and such action is permitted or required by Section 409A of the Code; if the Reorganization Event is not a “change in control event” as so defined or such action is not permitted or
required by Section 409A of the Code, and the acquiring or succeeding corporation does not assume or substitute the Restricted Stock Units pursuant to clause (i) of Section 9(b)(2)(i), then the unvested Restricted Stock Units shall terminate
immediately prior to the consummation of the Reorganization Event without any payment in exchange therefor. 

(iii)    For purposes of Section 9(b)(2)(i), an Award (other than Restricted Stock) shall be considered assumed if,
following consummation of the Reorganization Event, such Award confers the right to purchase or receive pursuant to the terms of such Award, for each share of Common Stock subject to the Award immediately prior to the consummation of the
Reorganization Event, the consideration (whether cash, securities or other property) received as a result of the Reorganization Event by holders of Common Stock for each share of Common Stock held immediately prior to the consummation of the
Reorganization Event (and if holders were offered a choice of consideration, the type of consideration chosen by the holders of a majority of the outstanding shares of Common Stock); provided, however, that if the consideration received as a
result of the Reorganization Event is not solely common stock of the acquiring or succeeding corporation (or an affiliate thereof), the Company may, with the consent of the acquiring or succeeding corporation, provide for the consideration to be
received upon the exercise or settlement of the Award to consist solely of such number of shares of common stock of the acquiring or succeeding corporation (or an affiliate thereof) that the Board determined to be equivalent in value (as of the date
of such determination or another date specified by the Board) to the per share consideration received by holders of outstanding shares of Common Stock as a result of the Reorganization Event. 

(3)    Consequences of a Reorganization Event on Restricted Stock. Upon the occurrence of a Reorganization Event
other than a liquidation or dissolution of the Company, the repurchase and other rights of the Company with respect to outstanding Restricted Stock shall inure to the benefit of the Company’s successor and shall, unless the Board determines
otherwise, apply to the cash, securities or other property which the Common Stock was converted into or exchanged for pursuant to such Reorganization Event in the same manner and to the same extent as they applied to such Restricted Stock;
provided, however, that the Board may provide for termination or deemed satisfaction of such repurchase or other rights under the instrument evidencing any Restricted Stock or any other agreement between a Participant and the Company,
either initially or by amendment, or provide for forfeiture of such Restricted Stock if issued at no cost. Upon the occurrence of a Reorganization Event involving the liquidation or dissolution of the Company, except to the extent specifically
provided to the contrary in the instrument evidencing any Restricted Stock or any other agreement between a Participant and the Company, all restrictions and conditions on all Restricted Stock then outstanding shall automatically be deemed
terminated or satisfied. 
  

	10.	General Provisions Applicable to Awards. 

 (a)    Transferability
of Awards. Except as the Board may otherwise determine or provide in an Award, Awards (or any interest in an Award, including, prior to exercise, any 

  
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interest in shares of Common Stock issuable upon exercise of an Option or SAR) shall not be sold, assigned, transferred (including by establishing any short position, put equivalent position (as
defined in Rule 16a-1 issued under the Exchange Act) or call equivalent position (as defined in Rule 16a-1 issued under the Exchange Act)), pledged, hypothecated or
otherwise encumbered by the person to whom they are granted, either voluntarily or by operation of law, and, during the life of the Participant, shall be exercisable only by the Participant; except that Awards, other than Awards subject to Section
409A of the Code, may be transferred to family members (as defined in Rule 701(c)(3) under the Securities Act) through gifts or (other than Incentive Stock Options) domestic relations orders or to an executor or guardian upon the death of the
Participant. The Company shall not be required to recognize any such permitted transfer until such time as such permitted transferee shall deliver to the Company a written instrument, as a condition to such transfer, in form and substance
satisfactory to the Company confirming that such transferee shall be bound by all of the terms and conditions of the Award. References to a Participant, to the extent relevant in the context, shall include references to authorized transferees. For
the avoidance of doubt, nothing contained in this Section 10(a) shall be deemed to restrict a transfer to the Company. 

(b)    Documentation. Each Award shall be evidenced in such form (written, electronic or otherwise) as the Board
shall determine. Each Award may contain terms and conditions in addition to those set forth in the Plan. 

(c)    Board Discretion. Except as otherwise provided by the Plan, each Award may be made alone or in addition or
in relation to any other Award. The terms of each Award need not be identical, and the Board need not treat Participants uniformly. 

(d)    Termination of Status. The Board shall determine the effect on an Award of the disability, death,
termination or other cessation of employment, authorized leave of absence or other change in the employment or other status of a Participant and the extent to which, and the period during which, the Participant, or the Participant’s legal
representative, conservator, guardian or Designated Beneficiary, may exercise rights under the Award.  

(e)    Withholding. The Participant must satisfy all applicable federal, state, and local or other income and
employment tax withholding obligations before the Company will deliver stock certificates or otherwise recognize ownership of Common Stock under an Award. The Company may elect to satisfy the withholding obligations through additional withholding on
salary or wages. If the Company elects not to or cannot withhold from other compensation, the Participant must pay the Company the full amount, if any, required for withholding or have a broker tender to the Company cash equal to the withholding
obligations. Payment of withholding obligations is due before the Company will issue any shares on exercise, vesting or release from forfeiture of an Award or at the same time as payment of the exercise or purchase price unless the Company
determines otherwise. If provided for in an Award or approved by the Board in its discretion, a Participant may satisfy such tax obligations in whole or in part by delivery (either by actual delivery or attestation) of shares of Common Stock,
including shares retained from the Award creating the tax obligation, valued at their fair market value (valued in the manner determined by (or in a manner approved by) the Company); provided, however, except as otherwise provided by the
Board, that the total tax withholding where stock is being used to satisfy such tax obligations cannot exceed the Company’s minimum statutory 

  
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withholding obligations (based on minimum statutory withholding rates for federal and state tax purposes, including payroll taxes, that are applicable to such supplemental taxable income),
except that, to the extent that the Company is able to retain shares of Common Stock having a fair market value (valued in the manner determined by (or in a manner approved by) the Company) that exceeds the statutory minimum applicable
withholding tax without financial accounting implications or the Company is withholding in a jurisdiction that does not have a statutory minimum withholding tax, the Company may retain such number of shares of Common Stock (up to the number of
shares having a fair market value (valued in the manner determined by (or in a manner approved by) the Company) equal to the maximum individual statutory rate of tax) as the Company shall determine in its discretion to satisfy the tax liability
associated with any Award. Shares used to satisfy tax withholding requirements cannot be subject to any repurchase, forfeiture, unfulfilled vesting or other similar requirements. 

(f)    Amendment of Award. 

(1)    The Board may amend, modify or terminate any outstanding Award, including but not limited to, substituting therefor
another Award of the same or a different type, changing the date of exercise or realization, and converting an Incentive Stock Option to a Nonstatutory Stock Option. The Participant’s consent to such action shall be required unless (i) the
Board determines that the action, taking into account any related action, does not materially and adversely affect the Participant’s rights under the Plan or (ii) the change is permitted under Section 9. 

(2)    The Board may, without stockholder approval, amend any outstanding Award granted under the Plan to provide an
exercise price per share that is lower than the then-current exercise price per share of such outstanding Award. The Board may also, without stockholder approval, cancel any outstanding award (whether or not granted under the Plan) and grant in
substitution therefor new Awards under the Plan covering the same or a different number of shares of Common Stock and having an exercise price per share lower than the then-current exercise price per share of the cancelled award. 

(g)    Conditions on Delivery of Stock. The Company will not be obligated to deliver any shares of Common Stock
pursuant to the Plan or to remove restrictions from shares previously issued or delivered under the Plan until (i) all conditions of the Award have been met or removed to the satisfaction of the Company, (ii) in the opinion of the
Company’s counsel, all other legal matters in connection with the issuance and delivery of such shares have been satisfied, including any applicable securities laws and regulations and any applicable stock exchange or stock market rules and
regulations, and (iii) the Participant has executed and delivered to the Company such representations or agreements as the Company may consider appropriate to satisfy the requirements of any applicable laws, rules or regulations. 

(h)    Acceleration. The Board may at any time provide that any Award shall become immediately exercisable in whole
or in part, free of some or all restrictions or conditions, or otherwise realizable in whole or in part, as the case may be. 

  
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	11.	Miscellaneous. 

 (a)    No Right To Employment or Other
Status. No person shall have any claim or right to be granted an Award by virtue of the adoption of the Plan, and the grant of an Award shall not be construed as giving a Participant the right to continued employment or any other relationship
with the Company. The Company expressly reserves the right at any time to dismiss or otherwise terminate its relationship with a Participant free from any liability or claim under the Plan, except as expressly provided in the applicable Award. 

(b)    No Rights As Stockholder. Subject to the provisions of the applicable Award, no Participant or
Designated Beneficiary shall have any rights as a stockholder with respect to any shares of Common Stock to be distributed with respect to an Award until becoming the record holder of such shares. 

(c)    Effective Date and Term of Plan. The Plan shall become effective on the date on which it is adopted by the
Board. No Awards shall be granted under the Plan after the expiration of 10 years from the earlier of (i) the date on which the Plan was adopted by the Board or (ii) the date the Plan was approved by the Company’s stockholders, but
Awards previously granted may extend beyond that date. 
 (d)    Amendment of Plan. The Board may amend, suspend
or terminate the Plan or any portion thereof at any time; provided that if at any time the approval of the Company’s stockholders is required as to any modification or amendment under Section 422 of the Code or any successor
provision with respect to Incentive Stock Options, the Board may not effect such modification or amendment without such approval. Unless otherwise specified in the amendment, any amendment to the Plan adopted in accordance with this Section 11(d)
shall apply to, and be binding on the holders of, all Awards outstanding under the Plan at the time the amendment is adopted, provided the Board determines that such amendment, taking into account any related action, does not materially and
adversely affect the rights of Participants under the Plan. 
 (e)    Authorization of
Sub-Plans (including Grants to non-U.S. Employees). The Board may from time to time establish one or more sub-plans under the
Plan for purposes of satisfying applicable securities, tax or other laws of various jurisdictions. The Board shall establish such sub-plans by adopting supplements to the Plan containing (i) such
limitations on the Board’s discretion under the Plan as the Board deems necessary or desirable or (ii) such additional terms and conditions not otherwise inconsistent with the Plan as the Board shall deem necessary or desirable. All
supplements adopted by the Board shall be deemed to be part of the Plan, but each supplement shall apply only to Participants within the affected jurisdiction and the Company shall not be required to provide copies of any supplement to Participants
in any jurisdiction which is not the subject of such supplement. 
 (f)    Compliance with
Section 409A of the Code. If and to the extent (i) any portion of any payment, compensation or other benefit provided to a Participant pursuant to the Plan in connection with Participant’s employment termination
constitutes “nonqualified deferred compensation” within the meaning of Section 409A of the Code and (ii) the Participant is a specified employee as defined in Section 409A(a)(2)(B)(i) of the Code, in each case as determined by the
Company in accordance with its procedures, by which determinations the Participant (through accepting the Award) agrees that the Participant is bound, such portion of 

  
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the payment, compensation or other benefit shall not be paid before the day that is six months plus one day after the date of “separation from service” (as determined under Section 409A
of the Code) (the “New Payment Date”), except as Section 409A of the Code may then permit. The aggregate of any payments that otherwise would have been paid to the Participant during the period between the date of separation from
service and the New Payment Date shall be paid to the Participant in a lump sum on such New Payment Date, and any remaining payments will be paid on their original schedule. 

The Company makes no representations or warranty and shall have no liability to the Participant or any other person if any provisions of or payments,
compensation or other benefits under the Plan are determined to constitute nonqualified deferred compensation subject to Section 409A of the Code but do not to satisfy the conditions of that section. 

(g)    Limitations on Liability. Notwithstanding any other provisions of the Plan, no individual
acting as a director, officer, other employee, or agent of the Company will be liable to any Participant, former Participant, spouse, beneficiary, or any other person for any claim, loss, liability, or expense incurred in connection with the
Plan, nor will such individual be personally liable with respect to the Plan because of any contract or other instrument such individual executes in such individual’s capacity as a director, officer, other employee, or agent of the Company. The
Company will indemnify and hold harmless each director, officer, other employee, or agent of the Company to whom any duty or power relating to the administration or interpretation of the Plan has been or will be delegated, against any cost or
expense (including attorneys’ fees) or liability (including any sum paid in settlement of a claim with the Board’s approval) arising out of any act or omission to act concerning the Plan unless arising out of such person’s own fraud
or bad faith. 
 (h)    Governing Law. The provisions of the Plan and all Awards made hereunder shall be governed
by and interpreted in accordance with the laws of the State of Delaware, excluding choice-of-law principles of the law of such state that would require the application
of the laws of a jurisdiction other than the State of Delaware. 
 * * * * 

  
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 AILERON THERAPEUTICS, INC. 

2016 STOCK INCENTIVE PLAN 

CALIFORNIA SUPPLEMENT 

Pursuant to Section 11(e) of the Plan, the Board has adopted this supplement for purposes of satisfying the requirements of Section 25102(o)
of the California Law: 
 Any Awards granted under the Plan to a Participant who is a resident of the State of California on the date of
grant (a “California Participant”) shall be subject to the following additional limitations, terms and conditions: 

1.    Additional Limitations on Options. 

(a)    Maximum Duration of Options. No Options granted to California Participants shall have a term in excess of 10
years measured from the Option grant date. 
 (b)    Minimum Exercise Period Following Termination. Unless a
California Participant’s employment is terminated for cause (as defined by applicable law, the terms of the Plan or option grant or a contract of employment), in the event of termination of employment of such Participant, such Participant shall
have the right to exercise an Option, to the extent that such Participant is entitled to exercise such Option on the date employment terminated, until the earlier of: (i) at least six months from the date of termination, if termination was
caused by such Participant’s death or disability, (ii) at least 30 days from the date of termination, if termination was caused other than by such Participant’s death or disability and (iii) the Option expiration date. 

2.    Additional Limitations for Other Stock-Based Awards. The terms of all Awards granted to a California Participant under
Section 8 of the Plan shall comply, to the extent applicable, with Section 260.140.46 of the California Code of Regulations. 

3.    Additional Limitations on Timing of Awards. No Award granted to a California Participant shall become exercisable, vested or
realizable, as applicable to such Award, unless the Plan has been approved by the holders of a majority of the Company’s outstanding voting securities by the later of (i) within 12 months before or after the date the Plan was adopted by
the Board, or (ii) prior to or within 12 months of the granting of any Award to a California Participant. 
 4.    Additional
Restriction Regarding Recapitalizations, Stock Splits, Etc. For purposes of Section 9 of the Plan, in the event of a stock split, reverse stock split, stock dividend, recapitalization, combination, reclassification or other distribution of
the Company’s securities underlying the Award without the receipt of consideration by the Company, the number of securities purchasable, and in the case of Options, the exercise price of such Options, shall be proportionately adjusted.

 5.    Additional Limitations on Transferability of Awards. Notwithstanding the provisions of Section 10(a) of the Plan, an
Award granted to a California Participant may not be transferred to an executor or guardian upon the disability of the Participant. 
 * * *
* 

  
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