EX-10.1



 Exhibit 10.1 

RESTORBIO, INC. 
 2017 STOCK
INCENTIVE PLAN 
 1. Purpose 
 The
purpose of this 2017 Stock Incentive Plan (the “Plan”) of resTORbio, 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 or 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 promulgated 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”). 

2. Eligibility 
 All of the Company’s
employees, officers, directors, consultants and advisors are eligible to be granted options, restricted stock, restricted stock units and other stock-based awards (each, an “Award”) under the Plan. Each person who receives an Award
under the Plan is deemed a “Participant”. 
 3. Administration and Delegation 

(a) Administration by Board of Directors. 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 decisions by the Board shall be made in the Board’s sole discretion and shall be final and binding on all persons having or claiming any interest in the Plan or in any Award. No director or person acting pursuant to the
authority delegated by the Board shall be liable for any action or determination relating to or under the Plan made in good faith. 
 (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 (a “Committee”). All references in
the Plan to the “Board” shall mean the Board or a Committee of the Board 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. To the extent permitted by applicable law, 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 or any of its present or future subsidiary corporations and to exercise such other powers
under the Plan as the Board may determine, provided that the Board shall fix the terms of the Awards to be granted by such officers (including the exercise price of such Awards, which may include a formula by which the exercise price will be
determined) and the maximum number of shares subject to Awards that the officers may grant; provided further, however, 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 under the
Exchange Act). 
 4. Stock Available for Awards. 

(a) Number of Shares. Subject to adjustment under Section 8, Awards may be made under the Plan for up to 581,875 shares of common
stock, $0.0001 par value per share, of the Company (the “Common Stock”). 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 covered by 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 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 (as hereinafter defined), the foregoing provisions 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. 
 (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 covered by 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. An Option that is not intended to be an Incentive Stock Option shall be designated a “Nonstatutory Stock Option”. 

  
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 (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 the Company, any of the Company’s present or 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. The Company shall have no liability to a Participant, or any other party, if an Option (or any part thereof) that is intended to be an Incentive Stock Option is not an Incentive Stock Option or for any action taken by
the Board, including without limitation the conversion of 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 Fair Market Value (as defined below) on the date the
Option is granted. 
 (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. 
 (e) Exercise of Options. Options may be exercised by delivery to the
Company of a written notice of exercise signed by the proper person or by any other form of notice (including electronic notice) approved by the Board together with payment in full as specified in Section 5(f) 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, 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 sole discretion, by delivery (either by actual delivery or attestation) of shares of Common Stock owned by the Participant valued at their fair market value as determined by (or in a manner approved by) the Board (“Fair
Market Value”), 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; 

(4) to the extent permitted by applicable law and provided for in the applicable option agreement or approved by the Board, in its sole
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 

  
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 (5) by any combination of the above permitted forms of payment. 

6. Restricted Stock; Restricted Stock Units 

(a) General. The Board may grant Awards entitling recipients 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 such shares if issued at no cost) from the recipient 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. Instead of granting Awards for Restricted Stock, the Board may grant Awards
entitling the recipient 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. Participants holding shares of Restricted Stock will be entitled to all ordinary cash dividends paid with respect to such
shares, unless otherwise provided by the Board. Unless otherwise provided, by the Board, if any dividends or distributions are paid in shares, or consist of a dividend or distribution to holders of Common Stock other than an ordinary cash dividend,
the shares, cash or other property will be subject to the same restrictions on transferability and forfeitability as the shares of Restricted Stock with respect to which they were paid. Each dividend payment will be made no later than the end of the
calendar year in which the dividends are paid to shareholders of that class of stock or, if later, the 15th day of the third month following the date the dividends are paid to shareholders of that class of stock. 

(2) Stock Certificates. The Company may require that any stock certificates issued in respect of shares of 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 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 (the “Designated Beneficiary”). In the absence of an effective designation by a Participant, “Designated Beneficiary” shall mean the Participant’s estate. 

  
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 7. Other Stock-Based Awards 

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, may be granted hereunder to Participants (“Other Stock-Based Awards”), including without limitation stock appreciation rights (“SARs”) and Awards entitling recipients to receive
shares of Common Stock to be delivered in the future. 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. 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. 
 8. 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 this Plan, (ii) the number and class of securities and exercise price per share of each outstanding Option, (iii) the number of shares subject to and the repurchase price per share subject to
each outstanding Restricted Stock Award, and (iv) the terms of each other outstanding 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. 

(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 exchange of all of the Common Stock of the Company for cash,
securities or other property pursuant to a share exchange transaction or (c) any liquidation or dissolution of the Company. 
 (2)
Consequences of a Reorganization Event on Awards Other than Restricted Stock Awards. 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 Awards on such terms as the Board determines: (i) provide that 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 the Participant’s unexercised Awards will terminate immediately prior to the consummation of such Reorganization Event unless exercised by the Participant within a specified
period following the date of such notice, (iii) provide that outstanding Awards shall become exercisable, 

  
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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 a Participant
equal to the excess, if any, of (A) the Acquisition Price times the number of shares of Common Stock subject to the Participant’s Awards (to the extent the exercise price does not exceed the Acquisition Price) over (B) the aggregate
exercise price of all such outstanding Awards and any applicable tax withholdings, in exchange for the termination of such Awards, (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 price thereof and any applicable tax withholdings) and (vi) any combination of the foregoing. In taking any of the actions permitted under this Section 8(b), 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. 

For purposes of clause (i) above, an Option shall be considered assumed if, following consummation of the Reorganization Event, the
Option confers the right to purchase, for each share of Common Stock subject to the Option 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 of Options to consist solely of common stock of the acquiring or succeeding corporation (or an
affiliate thereof) equivalent in value (as determined 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 Awards. Upon the occurrence of a Reorganization Event other than a
liquidation or dissolution of the Company, the repurchase and other rights of the Company under each outstanding Restricted Stock Award 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 the Common Stock subject to such Restricted
Stock Award. 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 Award or any other
agreement between a Participant and the Company, all restrictions and conditions on all Restricted Stock Awards then outstanding shall automatically be deemed terminated or satisfied. 

  
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 9. General Provisions Applicable to Awards 

(a) Transferability of Awards. Except as the Board may otherwise determine or provide in an Award, Awards shall not be sold, assigned,
transferred, pledged or otherwise encumbered by the person to whom they are granted, either voluntarily or by operation of law, except by will or the laws of descent and distribution or, other than in the case of an Incentive Stock Option, pursuant
to a qualified domestic relations order, and, during the life of the Participant, shall be exercisable only by the Participant. References to a Participant, to the extent relevant in the context, shall include references to authorized transferees.

 (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 decide 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 or release from forfeiture of
an Award or, if the Company so requires, at the same time as payment of the exercise price unless the Company determines otherwise. If provided for in an Award or approved by the Board in its sole discretion, a Participant may satisfy such tax
obligations in whole or in part by delivery of shares of Common Stock, including shares retained from the Award creating the tax obligation, valued at their Fair Market Value; 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 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). Shares surrendered to satisfy tax withholding requirements cannot be subject to any repurchase, forfeiture, unfulfilled vesting or other similar requirements. 

  
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 (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, would not materially and adversely affect the Participant’s rights under the Plan or (ii) the change is permitted under Section 8 hereof. 

(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 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 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 full or in part, free of some
or all restrictions or conditions, or otherwise realizable in full or in part, as the case may be. 
 10. Miscellaneous 

(a) No Right to Employment or Other Status. No person shall have any claim or right to be granted an Award, 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. 

  
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 (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 10(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 does not materially and adversely affect the rights of Participants under the Plan. 

(e) Authorization of Sub-Plans. The Board may from time to time establish one or more sub-plans under the Plan for purposes of satisfying applicable blue sky, securities or tax laws of various jurisdictions. The Board shall establish such sub-plans by adopting
supplements to this 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
Code Section 409A. No Award shall provide for deferral of compensation that does not comply with Section 409A of the Code, unless the Board, at the time of grant, specifically provides that the Award is not intended to
comply with Section 409A of the Code. The Company shall have no liability to a Participant, or any other party, if an Award that is intended to be exempt from, or compliant with, Section 409A is not so exempt or compliant or for any action
taken by the Board. 
 (g) 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 such state. 

  
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 RESTORBIO, INC. 

Restricted Stock Agreement 

Granted Under 2017 Stock Incentive Plan 

AGREEMENT made this [            ] day of
[                    ], 20[         ], between resTORbio, Inc., a Delaware corporation
(the “Company”), and [                            ] (the “Participant”). 

For valuable consideration, receipt of which is acknowledged, the parties hereto agree as follows: 

1. Purchase of Shares. 

The Company shall issue and sell to the Participant, and the Participant shall purchase from the Company, subject to the terms and conditions
set forth in this Agreement and in the Company’s 2017 Stock Incentive Plan (the “Plan”), [______] shares (the “Shares”) of common stock, $0.0001 par value, of the Company (“Common Stock”), at a purchase price of $[
] per share. The aggregate purchase price for the Shares shall be paid by the Participant by check payable to the order of the Company or such other method as may be acceptable to the Company. Upon receipt by the Company of payment for the
Shares, the Company shall issue to the Participant one or more certificates in the name of the Participant for that number of Shares purchased by the Participant. The Participant agrees that the Shares shall be subject to the purchase options set
forth in Sections 2 and 5 of this Agreement and the restrictions on transfer set forth in Section 4 of this Agreement. 
 2.
Purchase Option. 
 (a) In the event that the Participant ceases to be employed by the Company for any reason or no reason, with or
without cause, prior to [            ], the Company shall have the right and option (the “Purchase Option”) to purchase from the Participant, for a sum of $[__] per share
(the “Option Price”), some or all of the Unvested Shares (as defined below). 
 “Unvested Shares” means the total number
of Shares multiplied by the Applicable Percentage at the time the Purchase Option becomes exercisable by the Company. The “Applicable Percentage” shall be (i) 100% during the 12-month period
ending [                    ], 20[ ], (ii) [75%] less [12.5%] for each [six] months of employment completed by the Participant with the
Company from and after [        ], 20[ ], and (iii) zero on or after [                ],
20[        ]. 
 (b) If the Participant is employed by a parent or subsidiary of the Company,
any references in this Agreement to employment with the Company or termination of employment by or with the Company shall instead be deemed to refer to such parent or subsidiary. 







 3. Exercise of Purchase Option and Closing. 

(a) The Company may exercise the Purchase Option by delivering or mailing to the Participant (or his estate), within 90 days after the
termination of the employment of the Participant with the Company, a written notice of exercise of the Purchase Option. Such notice shall specify the number of Shares to be purchased. If and to the extent the Purchase Option is not so exercised by
the giving of such a notice within such 90-day period, the Purchase Option shall automatically expire and terminate effective upon the expiration of such 90-day period.

 (b) Within 10 days after delivery to the Participant of the Company’s notice of the exercise of the Purchase Option pursuant to
subsection (a) above, the Participant (or his estate) shall, pursuant to the provisions of the Joint Escrow Instructions referred to in Section 7 below, tender to the Company at its principal offices the certificate or certificates
representing the Shares which the Company has elected to purchase in accordance with the terms of this Agreement, duly endorsed in blank or with duly endorsed stock powers attached thereto, all in form suitable for the transfer of such Shares to the
Company. Promptly following its receipt of such certificate or certificates, the Company shall pay to the Participant the aggregate Option Price for such Shares (provided that any delay in making such payment shall not invalidate the Company’s
exercise of the Purchase Option with respect to such Shares). 
 (c) After the time at which any Shares are required to be delivered to the
Company for transfer to the Company pursuant to subsection (b) above, the Company shall not pay any dividend to the Participant on account of such Shares or permit the Participant to exercise any of the privileges or rights of a stockholder
with respect to such Shares, but shall, in so far as permitted by law, treat the Company as the owner of such Shares. 
 (d) The Option Price
may be payable, at the option of the Company, in cancellation of all or a portion of any outstanding indebtedness of the Participant to the Company or in cash (by check) or both. 

(e) The Company shall not purchase any fraction of a Share upon exercise of the Purchase Option, and any fraction of a Share resulting from a
computation made pursuant to Section 2 of this Agreement shall be rounded to the nearest whole Share (with any one-half Share being rounded upward). 

(f) The Company may assign its Purchase Option to one or more persons or entities. 

4. Restrictions on Transfer. 

(a) The Participant shall not sell, assign, transfer, pledge, hypothecate or otherwise dispose of, by operation of law or otherwise
(collectively “transfer”) any Shares, or any interest therein, that are subject to the Purchase Option, except that the Participant may transfer such Shares (i) to or for the benefit of any spouse, children, parents, uncles, aunts,
siblings, grandchildren and any other relatives approved by the Board of Directors (collectively, “Approved Relatives”) or to a trust established solely for the benefit of the Participant and/or


  
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Approved Relatives, provided that such Shares shall remain subject to this Agreement (including without limitation the restrictions on transfer set forth in this Section 4, the
Purchase Option and the right of first refusal set forth in Section 5) and such permitted transferee shall, as a condition to such transfer, deliver to the Company a written instrument confirming that such transferee shall be bound by all of
the terms and conditions of this Agreement or (ii) as part of the sale of all or substantially all of the shares of capital stock of the Company (including pursuant to a merger or consolidation), provided that, in accordance with the
Plan, the securities or other property received by the Participant in connection with such transaction shall remain subject to this Agreement. 

(b) The Participant shall not transfer any Shares, or any interest therein, that are no longer subject to the Purchase Option, except in
accordance with Section 5 below. 
 5. Right of First Refusal. 

(a) If the Participant proposes to transfer any Shares that are no longer subject to the Purchase Option (either because they are no longer
Unvested Shares or because the Purchase Option expired unexercised), then the Participant shall first give written notice of the proposed transfer (the “Transfer Notice”) to the Company. The Transfer Notice shall name the proposed
transferee and state the number of such Shares the Participant proposes to transfer (the “Offered Shares”), the price per share and all other material terms and conditions of the transfer. 

(b) For 30 days following its receipt of such Transfer Notice, the Company shall have the option to purchase all or part of the Offered Shares
at the price and upon the terms set forth in the Transfer Notice. In the event the Company elects to purchase all or part of the Offered Shares, it shall give written notice of such election to the Participant within such 30-day period. Within 10 days after his or her receipt of such notice, the Participant shall tender to the Company at its principal offices the certificate or certificates representing the Offered Shares to be
purchased by the Company, duly endorsed in blank by the Participant or with duly endorsed stock powers attached thereto, all in a form suitable for transfer of the Offered Shares to the Company. Promptly following receipt of such certificate or
certificates, the Company shall deliver or mail to the Participant a check in payment of the purchase price for such Offered Shares; provided that if the terms of payment set forth in the Transfer Notice were other than cash against
delivery, the Company may pay for the Offered Shares on the same terms and conditions as were set forth in the Transfer Notice; and provided further that any delay in making such payment shall not invalidate the Company’s exercise
of its option to purchase the Offered Shares. 
 (c) If the Company does not elect to acquire all of the Offered Shares, the Participant may,
within the 30-day period following the expiration of the option granted to the Company under subsection (b) above, transfer the Offered Shares which the Company has not elected to acquire to the proposed
transferee, provided that such transfer shall not be on terms and conditions more favorable to the transferee than those contained in the Transfer Notice. Notwithstanding any of the above, all Offered Shares transferred pursuant to
this Section 5 shall remain subject to this Agreement (including without limitation the restrictions on transfer set forth in Section 4 and the right of first refusal set forth in this Section 5) and such transferee shall, as a
condition to such transfer, deliver to the Company a written instrument confirming that such transferee shall be bound by all of the terms and conditions of this Agreement. 

  
 - 3 - 








 (d) After the time at which the Offered Shares are required to be delivered to the Company for
transfer to the Company pursuant to subsection (b) above, the Company shall not pay any dividend to the Participant on account of such Offered Shares or permit the Participant to exercise any of the privileges or rights of a stockholder with
respect to such Offered Shares, but shall, insofar as permitted by law, treat the Company as the owner of such Offered Shares. 
 (e) The
following transactions shall be exempt from the provisions of this Section 5: 
 (1) a transfer of Shares to or for the benefit of any
Approved Relatives, or to a trust established solely for the benefit of the Participant and/or Approved Relatives; 
 (2) any transfer
pursuant to an effective registration statement filed by the Company under the Securities Act of 1933, as amended (the “Securities Act”); and 

(3) the sale of all or substantially all of the outstanding shares of capital stock of the Company (including pursuant to a merger or
consolidation); 
 provided, however, that in the case of a transfer pursuant to clause (1) above, such Shares shall remain subject to this
Agreement (including without limitation the restrictions on transfer set forth in Section 4 and the right of first refusal set forth in this Section 5) and such transferee shall, as a condition to such transfer, deliver to the Company a
written instrument confirming that such transferee shall be bound by all of the terms and conditions of this Agreement. 
 (f) The Company
may assign its rights to purchase Offered Shares in any particular transaction under this Section 5 to one or more persons or entities. 

(g) The provisions of this Section 5 shall terminate upon the earlier of the following events: 

(1) the closing of the sale of shares of Common Stock in an underwritten public offering pursuant to an effective registration statement filed
by the Company under the Securities Act; or 
 (2) the sale of all or substantially all of the outstanding shares of capital stock, assets
or business of the Company, by merger, consolidation, sale of assets or otherwise (other than a merger or consolidation in which all or substantially all of the individuals and entities who were beneficial owners of the Company’s voting
securities immediately prior to such transaction beneficially own, directly or indirectly, more than 50% (determined on an as-converted basis) of the outstanding securities entitled to vote generally in the
election of directors of the resulting, surviving or acquiring corporation in such transaction). 

  
 - 4 - 








 (h) The Company shall not be required (1) to transfer on its books any of the Shares which
shall have been sold or transferred in violation of any of the provisions set forth in this Agreement, or (2) to treat as owner of such Shares or to pay dividends to any transferee to whom any such Shares shall have been so sold or transferred.

 6. Agreement in Connection with Initial Public Offering. 

The Participant agrees, in connection with the initial underwritten public offering of the Common Stock pursuant to a registration statement
under the Securities Act, (i) not to (a) offer, pledge, announce the intention to sell, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to
purchase, or otherwise transfer or dispose of, directly or indirectly, any shares of Common Stock or any securities convertible into or exercisable or exchangeable for shares of Common Stock or (b) enter into any swap or other agreement that
transfers, in whole or in part, any of the economic consequences of ownership of shares of Common Stock, whether any transaction described in clause (a) or (b) is to be settled by delivery of shares of Common Stock or other securities, in cash
or otherwise, during the period beginning on the date of the filing of such registration statement with the Securities and Exchange Commission and ending 180 days from the date of the final prospectus relating to the offering (plus up to an
additional 34 days to the extent requested by the managing underwriters for such offering in order to address Rule 2711(f) of the National Association of Securities Dealers, Inc. or any similar successor provision), and (ii) to execute any
agreement reflecting clause (i) above as may be requested by the Company or the managing underwriters at the time of such offering. The Company may impose stop-transfer instructions with respect to the shares of Common Stock or other securities
subject to the foregoing restriction until the end of the “lock-up” period. 
 7.
Escrow. 
 The Participant shall, upon the execution of this Agreement, execute Joint Escrow Instructions in the form attached to this
Agreement as Exhibit A. The Joint Escrow Instructions shall be delivered to the President of the Company, as escrow agent thereunder. The Participant shall deliver to such escrow agent a stock assignment duly endorsed in blank, in the form
attached to this Agreement as Exhibit B, and hereby instructs the Company to deliver to such escrow agent, on behalf of the Participant, the certificate(s) evidencing the Shares issued hereunder. Such materials shall be held by such escrow
agent pursuant to the terms of such Joint Escrow Instructions. 
 8. Restrictive Legends. 

All certificates representing Shares shall have affixed thereto legends in substantially the following form, in addition to any other legends
that may be required under federal or state securities laws: 
 “The shares of stock represented by this certificate are subject to
restrictions on transfer and an option to purchase set forth in a certain Restricted Stock Agreement between the corporation and the registered owner of these shares (or his predecessor in interest), and such Agreement is available for inspection
without charge at the office of the Secretary of the corporation.” 

  
 - 5 - 








 “The shares represented by this certificate have not been registered under the Securities
Act of 1933, as amended, and may not be sold, transferred or otherwise disposed of in the absence of an effective registration statement under such Act or an opinion of counsel satisfactory to the corporation to the effect that such registration is
not required.” 
 9. Provisions of the Plan. 

(a) This Agreement is subject to the provisions of the Plan, a copy of which is furnished to the Participant with this Agreement. 

(b) As provided in the Plan, upon the occurrence of a Reorganization Event (as defined in the Plan), the repurchase and other rights of the
Company hereunder shall inure to the benefit of the Company’s successor and shall apply to the cash, securities or other property which the Shares were converted into or exchanged for pursuant to such Reorganization Event in the same manner and
to the same extent as they applied to the Shares under this Agreement. If, in connection with a Reorganization Event, a portion of the cash, securities and/or other property received upon the conversion or exchange of the Shares is to be placed into
escrow to secure indemnification or similar obligations, the mix between the vested and unvested portion of such cash, securities and/or other property that is placed into escrow shall be the same as the mix between the vested and unvested portion
of such cash, securities and/or other property that is not subject to escrow. 
 10. Investment Representations. 

The Participant represents, warrants and covenants as follows: 

(a) The Participant is purchasing the Shares for his own account for investment only, and not with a view to, or for sale in connection with,
any distribution of the Shares in violation of the Securities Act, or any rule or regulation under the Securities Act. 
 (b) The Participant
has had such opportunity as he has deemed adequate to obtain from representatives of the Company such information as is necessary to permit him to evaluate the merits and risks of his investment in the Company. 

(c) The Participant has sufficient experience in business, financial and investment matters to be able to evaluate the risks involved in the
purchase of the Shares and to make an informed investment decision with respect to such purchase. 
 (d) The Participant can afford a
complete loss of the value of the Shares and is able to bear the economic risk of holding such Shares for an indefinite period. 

  
 - 6 - 








 (e) The Participant understands that (i) the Shares have not been registered under the
Securities Act and are “restricted securities” within the meaning of Rule 144 under the Securities Act; (ii) the Shares cannot be sold, transferred or otherwise disposed of unless they are subsequently registered under the
Securities Act or an exemption from registration is then available; (iii) in any event, the exemption from registration under Rule 144 will not be available for at least one year and even then will not be available unless a public market
then exists for the Common Stock, adequate information concerning the Company is then available to the public, and other terms and conditions of Rule 144 are complied with; and (iv) there is now no registration statement on file with the
Securities and Exchange Commission with respect to any stock of the Company and the Company has no obligation or current intention to register the Shares under the Securities Act. 

11. Withholding Taxes; Section 83(b) Election. 

(a) The Participant acknowledges and agrees that the Company has the right to deduct from payments of any kind otherwise due to the Participant
any federal, state or local taxes of any kind required by law to be withheld with respect to the purchase of the Shares by the Participant or the lapse of the Purchase Option. 

(b) The Participant has reviewed with the Participant’s own tax advisors the federal, state, local and foreign tax consequences of this
investment and the transactions contemplated by this Agreement. The Participant is relying solely on such advisors and not on any statements or representations of the Company or any of its agents. The Participant understands that the Participant
(and not the Company) shall be responsible for the Participant’s own tax liability that may arise as a result of this investment or the transactions contemplated by this Agreement. The Participant understands that it may be beneficial in many
circumstances to elect to be taxed at the time the Shares are purchased rather than when and as the Company’s Purchase Option expires by filing an election under Section 83(b) of the Internal Revenue Code of 1986 with the I.R.S. within 30
days from the date of purchase. 
 THE PARTICIPANT ACKNOWLEDGES THAT IT IS SOLELY THE PARTICIPANT’S RESPONSIBILITY AND NOT THE
COMPANY’S TO FILE TIMELY THE ELECTION UNDER SECTION 83(b), EVEN IF THE PARTICIPANT REQUESTS THE COMPANY OR ITS REPRESENTATIVES TO MAKE THIS FILING ON THE PARTICIPANT’S BEHALF. 

12. Miscellaneous. 
 (a)
No Rights to Employment. The Participant acknowledges and agrees that the vesting of the Shares pursuant to Section 2 hereof is earned only by continuing service as an employee at the will of the Company (not through the act of being
hired or purchasing shares hereunder). The Participant further acknowledges and agrees that the transactions contemplated hereunder and the vesting schedule set forth herein do not constitute an express or implied promise of continued engagement as
an employee or consultant for the vesting period, for any period, or at all. 

  
 - 7 - 








 (b) Severability. The invalidity or unenforceability of any provision of this Agreement
shall not affect the validity or enforceability of any other provision of this Agreement, and each other provision of this Agreement shall be severable and enforceable to the extent permitted by law. 

(c) Waiver. Any provision for the benefit of the Company contained in this Agreement may be waived, either generally or in any
particular instance, by the Board of Directors of the Company. 
 (d) Binding Effect. This Agreement shall be binding upon and inure
to the benefit of the Company and the Participant and their respective heirs, executors, administrators, legal representatives, successors and assigns, subject to the restrictions on transfer set forth in Sections 4 and 5 of this Agreement.

 (e) Notice. All notices required or permitted hereunder shall be in writing and deemed effectively given upon personal delivery or
five days after deposit in the United States Post Office, by registered or certified mail, postage prepaid, addressed to the other party hereto at the address shown beneath his or its respective signature to this Agreement, or at such other address
or addresses as either party shall designate to the other in accordance with this Section 12(e). 
 (f) Pronouns. Whenever the
context may require, any pronouns used in this Agreement shall include the corresponding masculine, feminine or neuter forms, and the singular form of nouns and pronouns shall include the plural, and vice versa. 

(g) Entire Agreement. This Agreement and the Plan constitute the entire agreement between the parties, and supersedes all prior
agreements and understandings, relating to the subject matter of this Agreement. 
 (h) Amendment. This Agreement may be amended or
modified only by a written instrument executed by both the Company and the Participant. 
 (i) Governing Law. This Agreement shall be
construed, interpreted and enforced in accordance with the internal laws of the State of Delaware without regard to any applicable conflicts of laws. 

(j) Participant’s Acknowledgments. The Participant acknowledges that he or she: (i) has read this Agreement; (ii) has
been represented in the preparation, negotiation, and execution of this Agreement by legal counsel of the Participant’s own choice or has voluntarily declined to seek such counsel; (iii) understands the terms and consequences of this
Agreement; (iv) is fully aware of the legal and binding effect of this Agreement; and (v) understands that the law firm of WilmerHale, is acting as counsel to the Company in connection with the transactions contemplated by the Agreement,
and is not acting as counsel for the Participant. 

  
 - 8 - 








 IN WITNESS WHEREOF, the parties hereto have executed this Agreement as of the day and year first
above written. 
  

			
	RESTORBIO, INC.


 
			
		
	By:	 	  

	Name:	 	
	Title:	 	


  

	
	PARTICIPANT:
	  

	[Name of Participant]


  

			
	Address:	 	  

		 	  




  
 - 9 - 








 Exhibit A 

RESTORBIO, INC. 
 Joint Escrow
Instructions 

                    ,
[        ] 
 resTORbio, Inc. 

President 
 501 Boylston Street, Suite 6102 

Boston, MA 02116 
 Dear Sir or Madam: 

As Escrow Agent for resTORbio, Inc., a Delaware corporation, and its successors in interest (the “Company”) under the Restricted
Stock Agreement (the “Agreement”) of even date herewith, to which a copy of these Joint Escrow Instructions is attached, and the undersigned person (“Holder”), you are hereby authorized and directed to hold the documents
delivered to you pursuant to the terms of the Agreement in accordance with the following instructions: 
 1. Appointment. Holder
irrevocably authorizes the Company to deposit with you any certificates evidencing Shares (as defined in the Agreement) to be held by you hereunder and any additions and substitutions to said Shares. For purposes of these Joint Escrow Instructions,
“Shares” shall be deemed to include any additional or substitute property. Holder does hereby irrevocably constitute and appoint you as his attorney-in-fact
and agent for the term of this escrow to execute with respect to such Shares all documents necessary or appropriate to make such Shares negotiable and to complete any transaction herein contemplated. Subject to the provisions of this Section 1
and the terms of the Agreement, Holder shall exercise all rights and privileges of a stockholder of the Company while the Shares are held by you. 

2. Closing of Purchase. 

(a) Upon any purchase by the Company of the Shares pursuant to the Agreement, the Company shall give to Holder and you a written notice
specifying the number of Shares to be purchased, the purchase price for the Shares, as determined pursuant to the Agreement, and the time for a closing hereunder (the “Closing”) at the principal office of the Company. Holder and the
Company hereby irrevocably authorize and direct you to close the transaction contemplated by such notice in accordance with the terms of said notice. 

(b) At the Closing, you are directed (i) to date the stock assignment form or forms necessary for the transfer of the Shares, (ii) to
fill in on such form or forms the number of Shares being transferred, and (iii) to deliver the same, together with the certificate or certificates evidencing the Shares to be transferred, to the Company against the simultaneous delivery to you
of the purchase price for the Shares being purchased pursuant to the Agreement. 

  
 - 10 - 








 3. Withdrawal. The Holder shall have the right to withdraw from this escrow any Shares as
to which the Purchase Option (as defined in the Agreement) has terminated or expired. 
 4. Duties of Escrow Agent. 

(a) Your duties hereunder may be altered, amended, modified or revoked only by a writing signed by all of the parties hereto. 

(b) You shall be obligated only for the performance of such duties as are specifically set forth herein and may rely and shall be protected in
relying or refraining from acting on any instrument reasonably believed by you to be genuine and to have been signed or presented by the proper party or parties. You shall not be personally liable for any act you may do or omit to do hereunder as
Escrow Agent or as attorney-in-fact of Holder while acting in good faith and in the exercise of your own good judgment, and any act done or omitted by you pursuant to
the advice of your own attorneys shall be conclusive evidence of such good faith. 
 (c) You are hereby expressly authorized to disregard any
and all warnings given by any of the parties hereto or by any other person or entity, excepting only orders or process of courts of law, and are hereby expressly authorized to comply with and obey orders, judgments or decrees of any court. If you
are uncertain of any actions to be taken or instructions to be followed, you may refuse to act in the absence of an order, judgment or decrees of a court. In case you obey or comply with any such order, judgment or decree of any court, you shall not
be liable to any of the parties hereto or to any other person or entity, by reason of such compliance, notwithstanding any such order, judgment or decree being subsequently reversed, modified, annulled, set aside, vacated or found to have been
entered without jurisdiction. 
 (d) You shall not be liable in any respect on account of the identity, authority or rights of the parties
executing or delivering or purporting to execute or deliver the Agreement or any documents or papers deposited or called for hereunder. 

(e) You shall be entitled to employ such legal counsel and other experts as you may deem necessary properly to advise you in connection with
your obligations hereunder and may rely upon the advice of such counsel. 
 (f) Your rights and responsibilities as Escrow Agent hereunder
shall terminate if (i) you cease to be Secretary of the Company or (ii) you resign by written notice to each party. In the event of a termination under clause (i), your successor as Secretary shall become Escrow Agent hereunder; in
the event of a termination under clause (ii), the Company shall appoint a successor Escrow Agent hereunder. 
 (g) If you reasonably
require other or further instruments in connection with these Joint Escrow Instructions or obligations in respect hereto, the necessary parties hereto shall join in furnishing such instruments. 

  
 - 11 - 








 (h) It is understood and agreed that if you believe a dispute has arisen with respect to the
delivery and/or ownership or right of possession of the securities held by you hereunder, you are authorized and directed to retain in your possession without liability to anyone all or any part of said securities until such dispute shall have been
settled either by mutual written agreement of the parties concerned or by a final order, decree or judgment of a court of competent jurisdiction after the time for appeal has expired and no appeal has been perfected, but you shall be under no duty
whatsoever to institute or defend any such proceedings. 
 (i) These Joint Escrow Instructions set forth your sole duties with respect to any
and all matters pertinent hereto and no implied duties or obligations shall be read into these Joint Escrow Instructions against you. 
 (j)
The Company shall indemnify you and hold you harmless against any and all damages, losses, liabilities, costs, and expenses, including attorneys’ fees and disbursements, (including without limitation the fees of counsel retained pursuant to
Section 4(e) above, for anything done or omitted to be done by you as Escrow Agent in connection with this Agreement or the performance of your duties hereunder, except such as shall result from your gross negligence or willful misconduct. 

5. Notice. Any notice required or permitted hereunder shall be given in writing and shall be deemed effectively given upon personal
delivery or upon deposit in the United States Post Office, by registered or certified mail with postage and fees prepaid, addressed to each of the other parties thereunto entitled at the following addresses, or at such other addresses as a party may
designate by ten days’ advance written notice to each of the other parties hereto. 
  

					
		 	COMPANY:	  	Notices to the Company shall be sent to the address set forth in the salutation hereto, Attn: President
			
		 	HOLDER:	  	Notices to Holder shall be sent to the address set forth below Holder’s signature below.
			
		 	ESCROW AGENT:	  	Notices to the Escrow Agent shall be sent to the address set forth in the salutation hereto.

 6. Miscellaneous. 

(a) By signing these Joint Escrow Instructions, you become a party hereto only for the purpose of said Joint Escrow Instructions, and you do
not become a party to the Agreement. 
 (b) This instrument shall be binding upon and inure to the benefit of the parties hereto and their
respective successors and permitted assigns. 

  
 - 12 - 








 
			
	Very truly yours,


  

			
	RESTORBIO, INC.


  

			
	By:	 	  

	Name:	 	
	Title:	 	


  

	
	HOLDER:
	
	  

	(Signature)
	
	  

	Print Name


  

			
	Address:	 	  

		 	  

	Date Signed:
                                         
   


 ESCROW AGENT: 

                          
                                       

  
 -13- 








 Exhibit B 

(STOCK ASSIGNMENT SEPARATE FROM CERTIFICATE) 

FOR VALUE RECEIVED, I hereby sell, assign and transfer unto
                     (                ) shares of
Common Stock, $0.0001 par value per share, of resTORbio, Inc. (the “Corporation”) standing in my name on the books of the Corporation represented by Certificate(s) Number
                     herewith, and do hereby irrevocably constitute and appoint
                             attorney to transfer the said stock on the books of the Corporation with full
power of substitution in the premises. 
  

	
	HOLDER:
	  

	Name:
	Dated:
                                         
                           


 IN PRESENCE OF
                                         
                            

NOTICE: The signature(s) to this assignment must correspond with the name as written upon the face of the certificate, in every particular,
without alteration, enlargement, or any change whatever and must be guaranteed by a commercial bank, trust company or member firm of the Boston, New York or Midwest Stock Exchange. 

  
 - 14 - 








 RESTORBIO, INC. 

Nonstatutory Stock Option Agreement 

Granted Under 2017 Stock Incentive Plan 

1. Grant of Option. 
 This agreement
evidences the grant by resTORbio, Inc., a Delaware corporation (the “Company”), on                 ,
20[        ] (the “Grant Date”) to [             ], an [employee], [consultant],
[director] of the Company (the “Participant”), of an option to purchase, in whole or in part, on the terms provided herein and in the Company’s 2017 Stock Incentive Plan (the “Plan”), a total of
[             ] shares (the “Shares”) of common stock, $0.0001 par value per share, of the Company (“Common Stock”) at
$[                     ] per Share. Unless earlier terminated, this option shall expire at 5:00 p.m., Eastern time, on
[                ] (the “Final Exercise Date”). 

It is intended that the option evidenced by this agreement shall not be an incentive stock option as defined in Section 422 of the
Internal Revenue Code of 1986, as amended, and any regulations promulgated thereunder (the “Code”). Except as otherwise indicated by the context, the term “Participant”, as used in this option, shall be deemed to include any
person who acquires the right to exercise this option validly under its terms. 
 2. Vesting Schedule. 

This option will become exercisable (“vest”) as to [25]% of the original number of Shares on the [first] anniversary of the Vesting
Commencement Date and as to an additional [12.5]% of the original number of Shares at the end of each successive [six-month] period following the first anniversary of the Vesting Commencement
Date until the [fourth] anniversary of the Vesting Commencement Date. The Vesting Commencement Date shall be [                    ]. 

The right of exercise shall be cumulative so that to the extent the option is not exercised in any period to the maximum extent permissible it
shall continue to be exercisable, in whole or in part, with respect to all Shares for which it is vested until the earlier of the Final Exercise Date or the termination of this option under Section 3 hereof or the Plan. 

3. Exercise of Option. 
 (a) Form of
Exercise. Each election to exercise this option shall be accompanied by a completed Notice of Stock Option Exercise in the form attached hereto as Exhibit A, signed by the Participant, and received by the Company at its principal office,
accompanied by this Agreement, and payment in full in the manner provided in the Plan. The Participant may purchase less than the number of shares covered hereby, provided that no partial exercise of this option may be for any fractional share. 

(b) Continuous Relationship with the Company Required. Except as otherwise provided in this Section 3, this option may not be
exercised unless the Participant, at the time he or she exercises this option, is, and has been at all times since the Grant Date, an [employee or officer of], or consultant or advisor to, the Company or any other entity the employees, officers,
directors, consultants, or advisors of which are eligible to receive option grants under the Plan (an “Eligible Participant”). 







 (c) Termination of Relationship with the Company. If the Participant ceases to be an
Eligible Participant for any reason, then, except as provided in paragraphs (d) and (e) below, the right to exercise this option shall terminate three months after such cessation (but in no event after the Final Exercise Date),
provided that this option shall be exercisable only to the extent that the Participant was entitled to exercise this option on the date of such cessation. Notwithstanding the foregoing, if the Participant, prior to the Final Exercise
Date, violates the non-competition or confidentiality provisions of any employment contract, confidentiality and nondisclosure agreement or other agreement between the Participant and the Company, the right to
exercise this option shall terminate immediately upon such violation. 
 (d) Exercise Period Upon Death or Disability. If the
Participant dies or becomes disabled (within the meaning of Section 22(e)(3) of the Code) prior to the Final Exercise Date while he or she is an Eligible Participant and the Company has not terminated such relationship for “cause” as
specified in paragraph (e) below, this option shall be exercisable, within the period of one year following the date of death or disability of the Participant, by the Participant (or in the case of death by an authorized transferee),
provided that this option shall be exercisable only to the extent that this option was exercisable by the Participant on the date of his or her death or disability, and further provided that this option shall not be exercisable after
the Final Exercise Date. 
 (e) Termination for Cause. If, prior to the Final Exercise Date, the Participant’s employment or
other relationship with the Company is terminated by the Company for Cause (as defined below), the right to exercise this option shall terminate immediately upon the effective date of such termination of employment or other relationship. If the
Participant is party to an employment, consulting or severance agreement with the Company that contains a definition of “cause” for termination of employment or other relationship, “Cause” shall have the meaning ascribed to such
term in such agreement. Otherwise, “Cause” shall mean willful misconduct by the Participant or willful failure by the Participant to perform his or her responsibilities to the Company (including, without limitation, breach by the
Participant of any provision of any employment, consulting, advisory, nondisclosure, non-competition or other similar agreement between the Participant and the Company), as determined by the Company, which
determination shall be conclusive. The Participant’s employment or other relationship shall be considered to have been terminated for “Cause” if the Company determines, within 30 days after the Participant’s resignation, that
termination for Cause was warranted. 
 4. Company Right of First Refusal. 

(a) Notice of Proposed Transfer. If the Participant proposes to sell, assign, transfer, pledge, hypothecate or otherwise dispose of, by
operation of law or otherwise (collectively, “transfer”) any Shares acquired upon exercise of this option, then the Participant shall first give written notice of the proposed transfer (the “Transfer Notice”) to the Company. The
Transfer Notice shall name the proposed transferee and state the number of such Shares the Participant proposes to transfer (the “Offered Shares”), the price per share and all other material terms and conditions of the transfer. 

  
 -2- 








 (b) Company Right to Purchase. For 30 days following its receipt of such Transfer Notice,
the Company shall have the option to purchase all or part of the Offered Shares at the price and upon the terms set forth in the Transfer Notice. In the event the Company elects to purchase all or part of the Offered Shares, it shall give written
notice of such election to the Participant within such 30-day period. Within 10 days after his or her receipt of such notice, the Participant shall tender to the Company at its principal offices the
certificate or certificates representing the Offered Shares to be purchased by the Company, duly endorsed in blank by the Participant or with duly endorsed stock powers attached thereto, all in a form suitable for transfer of the Offered Shares to
the Company. Promptly following receipt of such certificate or certificates, the Company shall deliver or mail to the Participant a check in payment of the purchase price for such Offered Shares; provided that if the terms of payment
set forth in the Transfer Notice were other than cash against delivery, the Company may pay for the Offered Shares on the same terms and conditions as were set forth in the Transfer Notice; and provided further that any delay in making
such payment shall not invalidate the Company’s exercise of its option to purchase the Offered Shares. 
 (c) Shares Not Purchased By
Company. If the Company does not elect to acquire all of the Offered Shares, the Participant may, within the 30-day period following the expiration of the option granted to the Company under subsection
(b) above, transfer the Offered Shares which the Company has not elected to acquire to the proposed transferee, provided that such transfer shall not be on terms and conditions more favorable to the transferee than those contained
in the Transfer Notice. Notwithstanding any of the above, all Offered Shares transferred pursuant to this Section 4 shall remain subject to the right of first refusal set forth in this Section 4 and such transferee shall, as a condition to
such transfer, deliver to the Company a written instrument confirming that such transferee shall be bound by all of the terms and conditions of this Section 4. 

(d) Consequences of Non-Delivery. After the time at which the Offered Shares are required to be
delivered to the Company for transfer to the Company pursuant to subsection (b) above, the Company shall not pay any dividend to the Participant on account of such Offered Shares or permit the Participant to exercise any of the privileges or
rights of a stockholder with respect to such Offered Shares, but shall, insofar as permitted by law, treat the Company as the owner of such Offered Shares. 

(e) Exempt Transactions. The following transactions shall be exempt from the provisions of this Section 4: 

(1) any transfer of Shares to or for the benefit of any spouse, child or grandchild of the Participant, or to a trust for their benefit; 

(2) any transfer pursuant to an effective registration statement filed by the Company under the Securities Act of 1933, as amended (the
“Securities Act”); and 
 (3) the sale of all or substantially all of the outstanding shares of capital stock of the Company
(including pursuant to a merger or consolidation); 

  
 -3- 








 provided, however, that in the case of a transfer pursuant to clause (1) above, such Shares
shall remain subject to the right of first refusal set forth in this Section 4. 
 (f) Assignment of Company Right. The Company
may assign its rights to purchase Offered Shares in any particular transaction under this Section 4 to one or more persons or entities. 

(g) Termination. The provisions of this Section 4 shall terminate upon the earlier of the following events: 

(1) the closing of the sale of shares of Common Stock in an underwritten public offering pursuant to an effective registration statement filed
by the Company under the Securities Act; or 
 (2) the sale of all or substantially all of the outstanding shares of capital stock, assets or
business of the Company, by merger, consolidation, sale of assets or otherwise (other than a merger or consolidation in which all or substantially all of the individuals and entities who were beneficial owners of the Company’s voting securities
immediately prior to such transaction beneficially own, directly or indirectly, more than 50% (determined on an as-converted basis) of the outstanding securities entitled to vote generally in the election of
directors of the resulting, surviving or acquiring corporation in such transaction). 
 (h) No Obligation to Recognize Invalid
Transfer. The Company shall not be required (1) to transfer on its books any of the Shares which shall have been sold or transferred in violation of any of the provisions set forth in this Section 4, or (2) to treat as owner of
such Shares or to pay dividends to any transferee to whom any such Shares shall have been so sold or transferred. 
 (i) Legends. The
certificate representing Shares shall bear a legend substantially in the following form (in addition to, or in combination with, any legend required by applicable federal and state securities laws and agreements relating to the transfer of the
Company securities): 
 “The shares represented by this certificate are subject to a right of first refusal in favor of the Company, as
provided in a certain stock option agreement with the Company.” 
 5. Agreement in Connection with Initial Public Offering. 

The Participant agrees, in connection with the initial underwritten public offering of the Common Stock pursuant to a registration statement
under the Securities Act, (i) not to (a) offer, pledge, announce the intention to sell, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to
purchase, or otherwise transfer or dispose of, directly or indirectly, any shares of Common Stock or any other securities of the Company or (b) enter into any swap or other agreement that transfers, in whole or in part, any of the economic
consequences of ownership of shares of Common Stock or other securities of the Company, whether any transaction described in clause (a) or (b) is to be settled by delivery of securities, in cash or otherwise, during the period beginning on the
date of 

  
 -4- 








 
the filing of such registration statement with the Securities and Exchange Commission and ending 180 days after the date of the final prospectus relating to the offering (plus up to an additional
34 days to the extent requested by the managing underwriters for such offering in order to address Rule 2711(f) of the National Association of Securities Dealers, Inc. or any similar successor provision), and (ii) to execute any agreement
reflecting clause (i) above as may be requested by the Company or the managing underwriters at the time of such offering. The Company may impose stop-transfer instructions with respect to the shares of Common Stock or other securities subject
to the foregoing restriction until the end of the “lock-up” period. 
 6. Withholding. 

No Shares will be issued pursuant to the exercise of this option unless and until the Participant pays to the Company, or makes provision
satisfactory to the Company for payment of, any federal, state or local withholding taxes required by law to be withheld in respect of this option. 
 7.
Transfer Restrictions. 
 (a) This option may not be sold, assigned, transferred, pledged or otherwise encumbered by the Participant,
either voluntarily or by operation of law, except by will or the laws of descent and distribution, and, during the lifetime of the Participant, this option shall be exercisable only by the Participant.
 
 (b) The Participant agrees that he or she will not transfer any Shares issued pursuant to the exercise of this option unless the
transferee, as a condition to such transfer, delivers to the Company a written instrument confirming that such transferee shall be bound by all of the terms and conditions of Section 4 and Section 5; provided that such a written
confirmation shall not be required with respect to (1) Section 4 after such provision has terminated in accordance with Section 4(g) or (2) Section 5 after the completion of the
lock-up period in connection with the Company’s initial underwritten public offering. 
 8. Provisions of
the Plan. 
 This option is subject to the provisions of the Plan (including the provisions relating to amendments to the Plan), a copy
of which is furnished to the Participant with this option. 

  
 -5- 








 IN WITNESS WHEREOF, the Company has caused this option to be executed under its corporate seal by
its duly authorized officer. This option shall take effect as a sealed instrument. 
  

			
	RESTORBIO, INC.


 
			
		
	By:	 	  

	Name:	 	
	Title:	 	



  
 -6- 








 PARTICIPANT’S ACCEPTANCE 

The undersigned hereby accepts the foregoing option and agrees to the terms and conditions thereof. The undersigned hereby acknowledges
receipt of a copy of the Company’s 2017 Stock Incentive Plan. 
  

			
	PARTICIPANT:
	  

		
	Address:	 	  

		 	  




  
 -7- 








 EXHIBIT A 

NOTICE OF STOCK OPTION EXERCISE 

[DATE]1 

resTORbio, Inc. 
 501 Boylston Street, Suite 6102 

Boston, MA 02116 
 Attention: Treasurer 

Dear Sir or Madam: 
 I am the holder of an
Nonstatutory Stock Option granted to me under the resTORbio, Inc. (the “Company”) 2017 Stock Incentive Plan on
[                    ]2 for the purchase of
[                    ]3 shares of Common Stock of the Company at a purchase price of
$[                    ]4 per share. 

I hereby exercise my option to purchase
[                ]5 shares of Common Stock (the “Shares”), for which I have enclosed
[                ]6 in the amount of
[                ]7. Please register my stock certificate as follows: 

 

							
		 	Name(s):	  	                                      
                  8	  	
		 		  	                                      
                  	  	
				
		 	Address:	  	                                      
                  	  	
		 		  	                                      
                  	  	

 I represent, warrant and covenant as follows: 

 

	1 	Enter date of exercise. 


	2 	Enter the date of grant. 


	3 	Enter the total number of shares of Common Stock for which the option was granted. 


	4 	Enter the option exercise price per share of Common Stock. 


	5 	Enter the number of shares of Common Stock to be purchased upon exercise of all or part of the option. 


	6 	Enter “cash”, “personal check” or if permitted by the option or Plan, “stock certificates No. XXXX and XXXX”. 


	7 	Enter the dollar amount (price per share of Common Stock times the number of shares of Common Stock to be purchased), or the number of shares tendered. Fair market value of shares tendered, together with cash or check,
must cover the purchase price of the shares issued upon exercise. 


	8 	Enter name(s) to appear on stock certificate in one of the following formats: (a) your name only (i.e., John Doe); (b) your name and other name (i.e., John Doe and Jane Doe, Joint Tenants with Right to
Survivorship); or for Nonstatutory Stock Options only, (c) a child’s name, with you as custodian (i.e. Jane Doe, Custodian for Tommy Doe). Note: There may be income and/or gift tax consequences for registering shares in a child’s
name. 


  
 -8- 








 1. I am purchasing the Shares for my own account for investment only, and not with a view to, or for sale in
connection with, any distribution of the Shares in violation of the Securities Act of 1933 (the “Securities Act”), or any rule or regulation under the Securities Act. 

2. I have had such opportunity as I have deemed adequate to obtain from representatives of the Company such information as is necessary to permit me to
evaluate the merits and risks of my investment in the Company. 
 3. I have sufficient experience in business, financial and investment matters to be able to
evaluate the risks involved in the purchase of the Shares and to make an informed investment decision with respect to such purchase. 
 4. I can afford a
complete loss of the value of the Shares and am able to bear the economic risk of holding such Shares for an indefinite period. 
 5. I understand that
(i) the Shares have not been registered under the Securities Act and are “restricted securities” within the meaning of Rule 144 under the Securities Act, (ii) the Shares cannot be sold, transferred or otherwise disposed of unless
they are subsequently registered under the Securities Act or an exemption from registration is then available; (iii) in any event, the exemption from registration under Rule 144 will not be available for at least one year and even then will not
be available unless a public market then exists for the Common Stock, adequate information concerning the Company is then available to the public, and other terms and conditions of Rule 144 are complied with; and (iv) there is now no
registration statement on file with the Securities and Exchange Commission with respect to any stock of the Company and the Company has no obligation or current intention to register the Shares under the Securities Act. 

 

	
	Very truly yours,
	  

	[Name]


  
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 RESTORBIO, INC. 

Incentive Stock Option Agreement 

Granted Under 2017 Stock Incentive Plan 

1. Grant of Option. 
 This agreement
evidences the grant by resTORbio, Inc., a Delaware corporation (the “Company”), on                  ,
20[        ] (the “Grant Date”) to [                ], an employee of the
Company (the “Participant”), of an option to purchase, in whole or in part, on the terms provided herein and in the Company’s 2017 Stock Incentive Plan (the “Plan”), a total of
[             ] shares (the “Shares”) of common stock, $0.0001 par value per share, of the Company (“Common Stock”) at
$[             ] per Share. Unless earlier terminated, this option shall expire at 5:00 p.m., Eastern time, on
[                ] (the “Final Exercise Date”). 

It is intended that the option evidenced by this agreement shall be an incentive stock option as defined in Section 422 of the Internal
Revenue Code of 1986, as amended, and any regulations promulgated thereunder (the “Code”). Except as otherwise indicated by the context, the term “Participant”, as used in this option, shall be deemed to include any person who
acquires the right to exercise this option validly under its terms. 
 2. Vesting Schedule. 

This option will become exercisable (“vest”) as to [25]% of the original number of Shares on the [first] anniversary of the
Vesting Commencement Date and as to an additional [12.5]% of the original number of Shares at the end of each successive [six-month] period following the first anniversary of the Vesting
Commencement Date until the [fourth] anniversary of the Vesting Commencement Date. The Vesting Commencement Date shall be [                ]. 

The right of exercise shall be cumulative so that to the extent the option is not exercised in any period to the maximum extent permissible it
shall continue to be exercisable, in whole or in part, with respect to all Shares for which it is vested until the earlier of the Final Exercise Date or the termination of this option under Section 3 hereof or the Plan. 

3. Exercise of Option. 
 (a) Form of
Exercise. Each election to exercise this option shall be accompanied by a completed Notice of Stock Option Exercise in the form attached hereto as Exhibit A, signed by the Participant, and received by the Company at its principal office,
accompanied by this Agreement, and payment in full in the manner provided in the Plan. The Participant may purchase less than the number of shares covered hereby, provided that no partial exercise of this option may be for any fractional share. 

(b) Continuous Relationship with the Company Required. Except as otherwise provided in this Section 3, this option may not be
exercised unless the Participant, at the time he or she exercises this option, is, and has been at all times since the Grant Date, an employee or officer of, or consultant or advisor to, the Company or any parent or subsidiary of the Company as
defined in Section 424(e) or (f) of the Code (an “Eligible Participant”). 







 (c) Termination of Relationship with the Company. If the Participant ceases to be an
Eligible Participant for any reason, then, except as provided in paragraphs (d) and (e) below, the right to exercise this option shall terminate three months after such cessation (but in no event after the Final Exercise Date),
provided that this option shall be exercisable only to the extent that the Participant was entitled to exercise this option on the date of such cessation. Notwithstanding the foregoing, if the Participant, prior to the Final Exercise
Date, violates the non-competition or confidentiality provisions of any employment contract, confidentiality and nondisclosure agreement or other agreement between the Participant and the Company, the right to
exercise this option shall terminate immediately upon such violation. 
 (d) Exercise Period Upon Death or Disability. If the
Participant dies or becomes disabled (within the meaning of Section 22(e)(3) of the Code) prior to the Final Exercise Date while he or she is an Eligible Participant and the Company has not terminated such relationship for “cause” as
specified in paragraph (e) below, this option shall be exercisable, within the period of one year following the date of death or disability of the Participant, by the Participant (or in the case of death by an authorized transferee),
provided that this option shall be exercisable only to the extent that this option was exercisable by the Participant on the date of his or her death or disability, and further provided that this option shall not be exercisable after
the Final Exercise Date. 
 (e) Termination for Cause. If, prior to the Final Exercise Date, the Participant’s employment is
terminated by the Company for Cause (as defined below), the right to exercise this option shall terminate immediately upon the effective date of such termination of employment. If the Participant is party to an employment or severance agreement with
the Company that contains a definition of “cause” for termination of employment, “Cause” shall have the meaning ascribed to such term in such agreement. Otherwise, “Cause” shall mean willful misconduct by the
Participant or willful failure by the Participant to perform his or her responsibilities to the Company (including, without limitation, breach by the Participant of any provision of any employment, consulting, advisory, nondisclosure, non-competition or other similar agreement between the Participant and the Company), as determined by the Company, which determination shall be conclusive. The Participant’s employment shall be considered to
have been terminated for Cause if the Company determines, within 30 days after the Participant’s resignation, that termination for Cause was warranted. 

4. Company Right of First Refusal. 
 (a)
Notice of Proposed Transfer. If the Participant proposes to sell, assign, transfer, pledge, hypothecate or otherwise dispose of, by operation of law or otherwise (collectively, “transfer”) any Shares acquired upon exercise of this
option, then the Participant shall first give written notice of the proposed transfer (the “Transfer Notice”) to the Company. The Transfer Notice shall name the proposed transferee and state the number of such Shares the Participant
proposes to transfer (the “Offered Shares”), the price per share and all other material terms and conditions of the transfer. 

  
 -2- 








 (b) Company Right to Purchase. For 30 days following its receipt of such Transfer Notice,
the Company shall have the option to purchase all or part of the Offered Shares at the price and upon the terms set forth in the Transfer Notice. In the event the Company elects to purchase all or part of the Offered Shares, it shall give written
notice of such election to the Participant within such 30-day period. Within 10 days after his or her receipt of such notice, the Participant shall tender to the Company at its principal offices the
certificate or certificates representing the Offered Shares to be purchased by the Company, duly endorsed in blank by the Participant or with duly endorsed stock powers attached thereto, all in a form suitable for transfer of the Offered Shares to
the Company. Promptly following receipt of such certificate or certificates, the Company shall deliver or mail to the Participant a check in payment of the purchase price for such Offered Shares; provided that if the terms of payment
set forth in the Transfer Notice were other than cash against delivery, the Company may pay for the Offered Shares on the same terms and conditions as were set forth in the Transfer Notice; and provided further that any delay in making
such payment shall not invalidate the Company’s exercise of its option to purchase the Offered Shares. 
 (c) Shares Not Purchased By
Company. If the Company does not elect to acquire all of the Offered Shares, the Participant may, within the 30-day period following the expiration of the option granted to the Company under subsection
(b) above, transfer the Offered Shares which the Company has not elected to acquire to the proposed transferee, provided that such transfer shall not be on terms and conditions more favorable to the transferee than those contained
in the Transfer Notice. Notwithstanding any of the above, all Offered Shares transferred pursuant to this Section 4 shall remain subject to the right of first refusal set forth in this Section 4 and such transferee shall, as a condition to
such transfer, deliver to the Company a written instrument confirming that such transferee shall be bound by all of the terms and conditions of this Section 4. 

(d) Consequences of Non-Delivery. After the time at which the Offered Shares are required to be
delivered to the Company for transfer to the Company pursuant to subsection (b) above, the Company shall not pay any dividend to the Participant on account of such Offered Shares or permit the Participant to exercise any of the privileges or
rights of a stockholder with respect to such Offered Shares, but shall, insofar as permitted by law, treat the Company as the owner of such Offered Shares. 

(e) Exempt Transactions. The following transactions shall be exempt from the provisions of this Section 4: 

(1) any transfer of Shares to or for the benefit of any spouse, child or grandchild of the Participant, or to a trust for their benefit; 

(2) any transfer pursuant to an effective registration statement filed by the Company under the Securities Act of 1933, as amended (the
“Securities Act”); and 
 (3) the sale of all or substantially all of the outstanding shares of capital stock of the Company
(including pursuant to a merger or consolidation); 

  
 -3- 








 provided, however, that in the case of a transfer pursuant to clause (1) above, such Shares
shall remain subject to the right of first refusal set forth in this Section 4. 
 (f) Assignment of Company Right. The Company
may assign its rights to purchase Offered Shares in any particular transaction under this Section 4 to one or more persons or entities. 

(g) Termination. The provisions of this Section 4 shall terminate upon the earlier of the following events: 

(1) the closing of the sale of shares of Common Stock in an underwritten public offering pursuant to an effective registration statement filed
by the Company under the Securities Act; or 
 (2) the sale of all or substantially all of the outstanding shares of capital stock, assets or
business of the Company, by merger, consolidation, sale of assets or otherwise (other than a merger or consolidation in which all or substantially all of the individuals and entities who were beneficial owners of the Company’s voting securities
immediately prior to such transaction beneficially own, directly or indirectly, more than 50% (determined on an as-converted basis) of the outstanding securities entitled to vote generally in the election of
directors of the resulting, surviving or acquiring corporation in such transaction). 
 (h) No Obligation to Recognize Invalid
Transfer. The Company shall not be required (1) to transfer on its books any of the Shares which shall have been sold or transferred in violation of any of the provisions set forth in this Section 4, or (2) to treat as owner of
such Shares or to pay dividends to any transferee to whom any such Shares shall have been so sold or transferred. 
 (i) Legends. The
certificate representing Shares shall bear a legend substantially in the following form (in addition to, or in combination with, any legend required by applicable federal and state securities laws and agreements relating to the transfer of the
Company securities): 
 “The shares represented by this certificate are subject to a right of first refusal in favor of the Company, as
provided in a certain stock option agreement with the Company.” 
 5. Agreement in Connection with Initial Public Offering. 

The Participant agrees, in connection with the initial underwritten public offering of the Common Stock pursuant to a registration statement under the
Securities Act, (i) not to (a) offer, pledge, announce the intention to sell, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to purchase, or
otherwise transfer or dispose of, directly or indirectly, any shares of Common Stock or any other securities of the Company or (b) enter into any swap or other agreement that transfers, in whole or in part, any of the economic consequences of
ownership of shares of Common Stock or other securities of the Company, whether any transaction described in clause (a) or (b) is to be settled by delivery of securities, in cash or otherwise, during the period beginning on the date of


  
 -4- 








 
the filing of such registration statement with the Securities and Exchange Commission and ending 180 days after the date of the final prospectus relating to the offering (plus up to an additional
34 days to the extent requested by the managing underwriters for such offering in order to address Rule 2711(f) of the National Association of Securities Dealers, Inc. or any similar successor provision), and (ii) to execute any agreement
reflecting clause (i) above as may be requested by the Company or the managing underwriters at the time of such offering. The Company may impose stop-transfer instructions with respect to the shares of Common Stock or other securities subject
to the foregoing restriction until the end of the “lock-up” period. 
 6. Tax Matters. 

(a) Withholding. No Shares will be issued pursuant to the exercise of this option unless and until the Participant pays to the Company,
or makes provision satisfactory to the Company for payment of, any federal, state or local withholding taxes required by law to be withheld in respect of this option. 

(b) Disqualifying Disposition. If the Participant disposes of Shares acquired upon exercise of this option within two years from the
Grant Date or one year after such Shares were acquired pursuant to exercise of this option, the Participant shall notify the Company in writing of such disposition. 

7. Transfer Restrictions. 
 (a) This
option may not be sold, assigned, transferred, pledged or otherwise encumbered by the Participant, either voluntarily or by operation of law, except by will or the laws of descent and distribution, and, during the lifetime of the Participant, this
option shall be exercisable only by the Participant.  
 (b) The Participant agrees that
he or she will not transfer any Shares issued pursuant to the exercise of this option unless the transferee, as a condition to such transfer, delivers to the Company a written instrument confirming that such transferee shall be bound by all of the
terms and conditions of Section 4 and Section 5; provided that such a written confirmation shall not be required with respect to (1) Section 4 after such provision has terminated in accordance with Section 4(g) or
(2) Section 5 after the completion of the lock-up period in connection with the Company’s initial underwritten public offering. 

8. Provisions of the Plan. 
 This option
is subject to the provisions of the Plan (including the provisions relating to amendments to the Plan), a copy of which is furnished to the Participant with this option. 

  
 -5- 








 IN WITNESS WHEREOF, the Company has caused this option to be executed under its corporate seal by
its duly authorized officer. This option shall take effect as a sealed instrument. 
  

			
	RESTORBIO, INC.


 
			
		
	By:	 	  

		 	Name:
		 	Title:



  
 -6- 








 PARTICIPANT’S ACCEPTANCE 

The undersigned hereby accepts the foregoing option and agrees to the terms and conditions thereof. The undersigned hereby acknowledges
receipt of a copy of the Company’s 2017 Stock Incentive Plan. 
  

			
	PARTICIPANT:
	  

	Address:	 	  

		 	  




  
 -7- 








 EXHIBIT A 

NOTICE OF STOCK OPTION EXERCISE 

[DATE]1 

resTORbio, Inc. 
 501 Boylston Street, Suite 6102 

Boston, MA 02116 
 Attention: Treasurer 

Dear Sir or Madam: 
 I am the holder of an
Incentive Stock Option granted to me under the resTORbio, Inc. (the “Company”) 2017 Stock Incentive Plan on [                ]2 for the purchase of
[                    ]3 shares of Common Stock of the Company at a purchase price of
$[                    ]4 per share. 

I hereby exercise my option to purchase
[                    ]5 shares of Common Stock (the “Shares”), for which
I have enclosed [                ]6 in the amount of
[                ]7. Please register my stock certificate as follows: 

 

							
		 	Name(s):	  	                                      
                  8	  	
		 		  	                                      
                  	  	
				
		 	Address:	  	                                      
                  	  	
		 		  	                                      
                  	  	

 I represent, warrant and covenant as follows: 

 

	1 	Enter date of exercise. 


	2 	Enter the date of grant. 


	3 	Enter the total number of shares of Common Stock for which the option was granted. 


	4 	Enter the option exercise price per share of Common Stock. 


	5 	Enter the number of shares of Common Stock to be purchased upon exercise of all or part of the option. 


	6 	Enter “cash”, “personal check” or if permitted by the option or Plan, “stock certificates No. XXXX and XXXX”. 


	7 	Enter the dollar amount (price per share of Common Stock times the number of shares of Common Stock to be purchased), or the number of shares tendered. Fair market value of shares tendered, together with cash or check,
must cover the purchase price of the shares issued upon exercise. 


	8 	Enter name(s) to appear on stock certificate in one of the following formats: (a) your name only (i.e., John Doe); (b) your name and other name (i.e., John Doe and Jane Doe, Joint Tenants with Right to
Survivorship); or for Nonstatutory Stock Options only, (c) a child’s name, with you as custodian (i.e. Jane Doe, Custodian for Tommy Doe). Note: There may be income and/or gift tax consequences for registering shares in a child’s
name. 


  
 -8- 








 1. I am purchasing the Shares for my own account for investment only, and not with a view to, or for sale in
connection with, any distribution of the Shares in violation of the Securities Act of 1933 (the “Securities Act”), or any rule or regulation under the Securities Act. 

2. I have had such opportunity as I have deemed adequate to obtain from representatives of the Company such information as is necessary to permit me to
evaluate the merits and risks of my investment in the Company. 
 3. I have sufficient experience in business, financial and investment matters to be able to
evaluate the risks involved in the purchase of the Shares and to make an informed investment decision with respect to such purchase. 
 4. I can afford a
complete loss of the value of the Shares and am able to bear the economic risk of holding such Shares for an indefinite period. 
 5. I understand that
(i) the Shares have not been registered under the Securities Act and are “restricted securities” within the meaning of Rule 144 under the Securities Act, (ii) the Shares cannot be sold, transferred or otherwise disposed of unless
they are subsequently registered under the Securities Act or an exemption from registration is then available; (iii) in any event, the exemption from registration under Rule 144 will not be available for at least one year and even then will not
be available unless a public market then exists for the Common Stock, adequate information concerning the Company is then available to the public, and other terms and conditions of Rule 144 are complied with; and (iv) there is now no
registration statement on file with the Securities and Exchange Commission with respect to any stock of the Company and the Company has no obligation or current intention to register the Shares under the Securities Act. 

 

	
	Very truly yours,
	
	  

	[Name]


  
 -9-