Document:

EX-10.2

 Exhibit 10.2 

PRELUDE THERAPEUTICS INCORPORATED 

2016 STOCK INCENTIVE PLAN 

As Amended and Restated on September 2, 2020 

1. PURPOSE. The purpose of this Plan is to provide incentives to attract, retain and motivate eligible persons
whose present and potential contributions are important to the success of the Company, its Parent and Subsidiaries by offering eligible persons an opportunity to participate in the Company’s future performance through the grant of Awards
covering Shares. Capitalized terms not defined in the text are defined in Section 14 hereof. Although this Plan is intended to be a written compensatory benefit plan within the meaning of Rule 701, grants may be made pursuant to this Plan
that do not qualify for exemption under Rule 701. 
 2. SHARES SUBJECT TO THE PLAN. 

2.1 Number of Shares Available. Subject to Sections 2.2 and 11 hereof, the total number of Shares reserved
and available for grant and issuance pursuant to this Plan will be 10,420,296 Shares plus (a) any authorized shares not issued or subject to outstanding grants under the Company’s 2016 Stock Incentive Plan (the “Prior
Plan”) on the Effective Date (as defined in Section 13.1 hereof); (b) shares that are subject to issuance under the Prior Plan but cease to be subject to an award for any reason other than exercise of an option after the Effective
Date; and (c) shares that were issued under the Prior Plan which are repurchased by the Company or which are forfeited or used to pay withholding obligations or pay the exercise price of an Option. Subject to Sections 2.2 and 11 hereof,
(A) in the event that Shares previously issued under the Plan are reacquired by the Company pursuant to a forfeiture provision, right of first refusal, or repurchase by the Company, such Shares shall be added to the number of Shares then
available for issuance under the Plan; (B) in the event that Shares that otherwise would have been issuable under the Plan are withheld by the Company in payment of the Purchase Price, Exercise Price or withholding obligations, such Shares
shall remain available for issuance under the Plan; and (C) in the event that an outstanding Option, Restricted Stock Unit or SAR for any reason expires or is cancelled, forfeited or terminated, the Shares allocable to the unexercised or
unsettled portion of such Option, Restricted Stock Unit or SAR, as applicable, shall remain available for issuance under the Plan. To the extent an Award is settled in cash, the cash settlement shall not reduce the number of Shares remaining
available for issuance under the Plan. At all times the Company will reserve and keep available a sufficient number of Shares as will be required to satisfy the requirements of all Awards granted and outstanding under this Plan. In no event shall
the total number of Shares issued (counting each reissuance of a Share that was previously issued and then reacquired by the Company pursuant to a forfeiture provision, right of first refusal, or repurchase by the Company as a separate issuance)
under the Plan upon exercise of ISOs (as defined in Section 4 hereof) exceed 20,840,592 Shares (adjusted in proportion to any adjustments under Section 2.2 hereof) over the term of the Plan. 

2.2 Adjustment of Shares. In the event that the number of outstanding shares of the Company’s Common Stock is
changed by a stock dividend, recapitalization, stock split, reverse stock split, subdivision, combination, reclassification or other change in the capital structure of the Company affecting Shares without consideration, then in order to prevent
diminution or enlargement of the benefits or potential benefits intended to be made available under the Plan (a) the number and class of Shares reserved for issuance under this Plan, (b) the Exercise Prices of and number and class of
Shares subject to outstanding Options and SARs, and (c) the Purchase Prices of and/or number and class of Shares subject to other outstanding Awards will (to the extent appropriate) be proportionately adjusted, subject to any required action by
the Board or the stockholders of the Company and compliance with applicable securities or other laws; provided, however, that fractions of a Share will not be issued but will either be paid in cash at the Fair Market
Value of such fraction of a Share or will be rounded down to the nearest whole Share, as determined by the Committee. 

  
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 3. PLAN FOR BENEFIT OF SERVICE PROVIDERS. 

3.1 Eligibility. The Committee will have the authority to select persons to receive Awards. ISOs may be granted
only to employees (including officers and directors who are also employees) of the Company or of a Parent or Subsidiary of the Company. NQSOs (as defined in Section 4 hereof) and all other types of Awards may be granted to employees, officers,
directors and consultants of the Company or any Parent or Subsidiary of the Company; provided such consultants render bona fide services not in connection with the offer and sale of securities in a capital-raising transaction when Rule
701 is to apply to the Award granted for such services. A person may be granted more than one Award under this Plan. 
 3.2 No
Obligation to Employ. Nothing in this Plan or any Award granted under this Plan will confer or be deemed to confer on any Participant any right to continue in the employ of, or to continue any other relationship with, the Company or
any Subsidiary or Parent of the Company or limit in any way the right of the Company or any Subsidiary or Parent of the Company to terminate Participant’s employment or other relationship at any time, with or without Cause. 

4. OPTIONS. The Committee may grant Options to eligible persons described in Section 3 hereof and will
determine whether such Options will be Incentive Stock Options within the meaning of the Code (“ISOs”) or Nonqualified Stock Options (“NQSOs”), the number of Shares subject to the Option, the Exercise
Price of the Option, the period during which the Option may be exercised, and all other terms and conditions of the Option, subject to the following. 

4.1 Form of Option Grant. Each Option granted under this Plan will be evidenced by an Award Agreement which will
expressly identify the Option as an ISO or an NQSO (“Stock Option Agreement”), and will be in such form and contain such provisions (which may be electronic or written and need not be the same for each Participant) as the
Committee may from time to time approve, and which will comply with and be subject to the terms and conditions of this Plan. 
 4.2
Date of Grant. The date of grant of an Option will be the date on which the Committee makes the determination to grant such Option, unless a later date is otherwise specified by the Committee. The Stock Option Agreement and a
copy of this Plan will be delivered to the Participant within a reasonable time after the granting of the Option. 
 4.3
Exercise Period. Options may be exercisable within the time or upon the events determined by the Committee in the Award Agreement and may be awarded as immediately exercisable but subject to repurchase pursuant to
Section 10 hereof or may be exercisable within the times or upon the events determined by the Committee as set forth in the Stock Option Agreement governing such Option; provided, however, that (a) no Option
will be exercisable after the expiration of ten (10) years from the date the Option is granted; and (b) no ISO granted to a person who directly or by attribution owns more than ten percent (10%) of the total combined voting power of all
classes of stock of the Company or of any Subsidiary or Parent of the Company (“Ten Percent Stockholder”) will be exercisable after the expiration of five (5) years from the date the ISO is granted; but in no event shall
an Option granted to an employee who is a non-exempt employee for purposes of overtime pay under the U.S. Fair Labor Standards Act of 1938 be exercisable earlier than six (6) months after its date of
grant. The Committee also may provide for Options to become exercisable at one time or from time to time, periodically or otherwise, in such number of Shares or percentage of Shares as the Committee determines. 

4.4 Exercise Price. The Exercise Price of an Option will be determined by the Committee when the Option is granted
and shall not be less than the Fair Market Value per Share on the date of grant unless expressly determined in writing by the Committee on the Options’s date of grant; provided that the Exercise Price of an ISO granted to a Ten
Percent Stockholder will not be less than one hundred ten percent (110%) of the Fair Market Value of the Shares on the date of grant. Payment for the Shares purchased must be made in accordance with Section 8 hereof. 

  
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 4.5 Method of Exercise. Options may be exercised only by
delivery to the Company of a stock option exercise agreement (accepted via written, electronic or other means) (the “Exercise Agreement”) in a form approved by the Committee (which need not be the same for each Participant).
The Exercise Agreement will state (a) the number of Shares being purchased, (b) the restrictions imposed on the Shares purchased under such Exercise Agreement, if any, and (c) such representations and agreements regarding
Participant’s investment intent and access to information and other matters, if any, as may be required or desirable by the Company to comply with applicable securities or other laws. Each Participant’s Exercise Agreement may be modified
by (i) agreement of Participant and the Company or (ii) substitution by the Company, upon becoming a public company, in order to add the payment terms set forth in Section 8.1 that apply to a public company and such other terms as
shall be necessary or advisable in order to exercise a public company option. Upon exercise of an Option, Participant shall execute and deliver to the Company the Exercise Agreement then in effect, together with payment in full of the Exercise Price
for the number of Shares being purchased and satisfaction of any applicable Tax-Related Obligations (as defined in Section 8.2 hereof). No adjustment will be made for a dividend or other right for which
the record date is prior to the date the Shares are issued, except as provided in Section 2.2 of the Plan. Exercising an Option in any manner will decrease the number of Shares thereafter available, both for purposes of the Plan and for sale
under the Option, by the number of Shares as to which the Option is exercised. 
 4.6 Termination. Subject to
earlier termination pursuant to Sections 11 and 13 hereof and subject to any longer exercise periods set forth in the Stock Option Agreement, exercise of an Option will always be subject to the following terms and conditions. 

4.6.1 Other than Death or Disability or for Cause. If the Participant is Terminated for any reason other than death, Disability or for
Cause, then the Participant may exercise such Participant’s Options only to the extent that such Options are exercisable as to Vested Shares upon the Termination Date, except as otherwise determined by the Committee or required by applicable
law. Such Options must be exercised by the Participant, if at all, as to all or some of the Vested Shares calculated as of the Termination Date or such other date determined by the Committee, within three (3) months after the Termination Date
(or within such shorter time period, not less than thirty (30) days, or within such longer time period after the Termination Date as may be determined by the Committee or required by applicable law, with any exercise beyond three
(3) months after the date Participant ceases to be an employee deemed to be an NQSO) but, in any event, no later than the expiration date of the Options. 

4.6.2 Death or Disability. If the Participant is Terminated because of Participant’s death or Disability (or the Participant dies
within three (3) months after a Termination other than for Cause), then Participant’s Options may be exercised only to the extent that such Options are exercisable as to Vested Shares on the Termination Date, except as otherwise determined
by the Committee or required by applicable law. Such Options must be exercised by Participant (or Participant’s legal representative or authorized assignee), if at all, as to all or some of the Vested Shares calculated as of the Termination
Date or such other date determined by the Committee, within twelve (12) months after the Termination Date (or within such shorter time period, not less than six (6) months, or within such longer time period, after the Termination Date as
may be determined by the Committee or required by applicable law, with any exercise beyond (a) three (3) months after the date Participant ceases to be an employee when the Termination is for any reason other than the Participant’s
death or disability, within the meaning of Section 22(e)(3) of the Code, or (b) twelve (12) months after the date Participant ceases to be an employee when the Termination is for Participant’s disability, within the meaning of
Section 22(e)(3) of the Code, deemed to be an NQSO) but in any event no later than the expiration date of the Options. 
 4.6.3 For
Cause. If the Participant is Terminated for Cause, the Participant may exercise such Participant’s Options, but not to an extent greater than such Options are exercisable as to Vested Shares upon the Termination Date and Participant’s
Options shall expire on such Participant’s Termination Date, or at such later time and on such conditions as are determined by the Committee. 

  
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 4.7 Limitations on Exercise. The Committee may specify a
reasonable minimum number of Shares that may be purchased on any exercise of an Option, provided that such minimum number will not prevent Participant from exercising the Option for the full number of Shares for which it is then
exercisable. 
 4.8 Limitations on ISOs. The aggregate Fair Market Value (determined as of the date of grant) of
Shares with respect to which ISOs are exercisable for the first time by a Participant during any calendar year (under this Plan or under any other incentive stock option plan of the Company or any Parent or Subsidiary of the Company) will not exceed
One Hundred Thousand Dollars ($100,000). If the Fair Market Value of Shares on the date of grant with respect to which ISOs are exercisable for the first time by a Participant during any calendar year exceeds One Hundred Thousand Dollars ($100,000),
then the Options for the first One Hundred Thousand Dollars ($100,000) worth of Shares to become exercisable in such calendar year will be ISOs and the Options for the amount in excess of One Hundred Thousand Dollars ($100,000) that become
exercisable in that calendar year will be NQSOs. In the event that the Code or the regulations promulgated thereunder are amended after the Effective Date (as defined in Section 13.1 hereof) to provide for a different limit on the Fair Market
Value of Shares permitted to be subject to ISOs, then such different limit will be automatically incorporated herein and will apply to any Options granted after the effective date of such amendment. 

4.9 Modification, Extension or Renewal. The Committee may modify, extend or renew outstanding Options and
authorize the grant of new Options in substitution therefor, provided that any such action may not, without the written consent of a Participant, impair any of such Participant’s rights under any Option previously granted, unless
for the purpose of complying with applicable laws and regulations. Any outstanding ISO that is modified, extended, renewed or otherwise altered will be treated in accordance with Section 424(h) of the Code. Subject to Section 4.10 hereof,
the Committee may reduce the Exercise Price of outstanding Options without the consent of Participants by a written notice to them; provided, however, that the Exercise Price may not be reduced below the minimum Exercise
Price that would be permitted under Section 4.4 hereof for Options granted on the date the action is taken to reduce the Exercise Price. 

4.10 No Disqualification. Notwithstanding any other provision in this Plan, no term of this Plan relating to ISOs
will be interpreted, amended or altered, nor will any discretion or authority granted under this Plan be exercised, so as to disqualify this Plan under Section 422 of the Code or, without the consent of the Participant, to disqualify any
Participant’s ISO under Section 422 of the Code. 
 5. RESTRICTED STOCK. A Restricted Stock Award is
an offer by the Company to sell to an eligible person Shares that are subject to certain specified restrictions. The Committee will determine to whom an offer will be made, the number of Shares the person may purchase, the Purchase Price, the
restrictions to which the Shares will be subject, and all other terms and conditions of the Restricted Stock Award, subject to the following terms and conditions. 

5.1 Form of Restricted Stock Award. All purchases under a Restricted Stock Award made pursuant to this Plan will
be evidenced by an Award Agreement (“Restricted Stock Purchase Agreement”) that will be in such form (which need not be the same for each Participant) as the Committee will from time to time approve, and will comply with and
be subject to the terms and conditions of this Plan. The Restricted Stock Award will be accepted by the Participant’s execution and delivery of the Restricted Stock Purchase Agreement (accepted via written, electronic or other means) and full
payment for the Shares to the Company within thirty (30) days from the date the Restricted Stock Purchase Agreement is delivered to the person. If such person does not execute and deliver the Restricted Stock Purchase Agreement along with full
payment for the Shares to the Company within such thirty (30) days, then the offer will terminate, unless otherwise determined by the Committee. 

  
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 5.2 Purchase Price. The Purchase Price of Shares sold pursuant
to a Restricted Stock Award will be determined by the Committee on the date the Restricted Stock Award is granted. Payment of the Purchase Price must be made in accordance with Section 8 hereof. 

5.3 Dividends and Other Distributions. Participants holding Restricted Stock Awards will be entitled to receive
all dividends and other distributions paid with respect to such Shares, unless the Committee provides otherwise at the time the Award is granted. If any such dividends or distributions are paid in Shares, the Shares will be subject to the same
restrictions on transferability and forfeitability as the Restricted Stock Awards with respect to which they were paid. 
 5.4
Restrictions. Restricted Stock Awards may be subject to the restrictions set forth in Sections 9 and 10 hereof. 

6. RESTRICTED STOCK UNITS. 

6.1 Awards of Restricted Stock Units. A Restricted Stock Unit (“RSU”) is an Award covering
a number of Shares that may be settled in cash, by issuance of those Shares at a date in the future, or by a combination of cash and Shares. No Purchase Price shall apply to an RSU settled in Shares. All grants of RSUs will be evidenced by an Award
Agreement (the “RSU Agreement”) that will be in such form (which need not be the same for each Participant) as the Committee will from time to time approve, and will comply with and be subject to the terms and conditions of
this Plan. No RSU will have a term longer than ten (10) years from the date the RSU is granted. 
 6.2 Form and Timing of
Settlement. To the extent permissible under applicable law, the Committee may permit a Participant to defer payment (including settlement) under an RSU to a date or dates after the RSU has vested, provided that the terms
of the RSU and any deferral satisfy the requirements of Section 409A of the Code (or any successor) and any regulations or rulings promulgated thereunder, to the extent the Participant is subject to Section 409A of the Code. Payment may be
made in the form of cash or whole Shares or a combination thereof, all as the Committee determines. 
 6.3 Dividend Equivalent
Payments. The Board may permit Participants holding RSUs to receive dividend equivalent payments on outstanding RSUs if and when dividends are paid to stockholders on Shares. In the discretion of the Board, such dividend
equivalent payments may be paid in cash or Shares and they may either be paid at the same time as dividend payments are made to stockholders or delayed until Shares are issued pursuant to the RSU grants and may be subject to the same vesting or
performance requirements as the RSUs. If the Board permits dividend equivalent payments to be made on RSUs, the terms and conditions for such dividend equivalent payments will be set forth in the RSU Agreement. 

7. STOCK APPRECIATION RIGHTS. 

7.1 Awards of SARs. Stock Appreciation Rights (“SARs”) may be settled in cash or Shares
(which may consist of Restricted Stock or RSUs) or a combination thereof, having a value equal to the value determined by multiplying the difference between the Fair Market Value on the date of exercise over the Exercise Price and the number of
Shares with respect to which the SAR is being exercised. All grants of SARs made pursuant to this Plan will be evidenced by an Award Agreement (the “SAR Agreement”) that will be in such form (which need not be the same for
each Participant) as the Committee will from time to time approve, and will comply with and be subject to the terms and conditions of this Plan. 

  
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 7.2 Exercise Period and Expiration Date. A SAR will be
exercisable within the times or upon the occurrence of events determined by the Committee and set forth in the SAR Agreement. The SAR Agreement shall set forth the expiration date; provided that no SAR will be exercisable after the
expiration of ten (10) years from the date the SAR is granted. 
 7.3 Exercise Price. The Committee will
determine the Exercise Price of the SAR when the SAR is granted, which may not be less than the Fair Market Value on the date of grant. 

7.4 Termination. Subject to earlier termination pursuant to Sections 11 and 13 hereof and subject to any
longer exercise periods set forth in the SAR Agreement, exercise of SARs will always be subject to the following terms and conditions. 

7.4.1 Other than Death or Disability or for Cause. If the Participant is Terminated for any reason other than death, Disability or for
Cause, then the Participant may exercise such Participant’s SARs only to the extent that such SARs are exercisable as to Vested Shares upon the Termination Date or as otherwise determined by the Committee or as required by applicable law. SARs
must be exercised by the Participant, if at all, as to all or some of the Vested Shares calculated as of the Termination Date or such other date determined by the Committee, within three (3) months after the Termination Date (or within such
shorter time period, not less than thirty (30) days, or within such longer time period after the Termination Date as may be determined by the Committee or as required by applicable law), but in any event no later than the expiration date of the
SARs. 
 7.4.2 Death or Disability. If the Participant is Terminated because of Participant’s death or Disability (or the
Participant dies within three (3) months after a Termination other than for Cause), then Participant’s SARs may be exercised only to the extent that such SARs are exercisable as to Vested Shares on the Termination Date or as otherwise
determined by the Committee or as required by applicable law. Such SARs must be exercised by Participant (or Participant’s legal representative or authorized assignee), if at all, as to all or some of the Vested Shares calculated as of the
Termination Date or such other date determined by the Committee, within twelve (12) months after the Termination Date (or within such shorter time period, not less than six (6) months, or within such longer time period after the
Termination Date as may be determined by the Committee or as required by applicable law), but in any event no later than the expiration date of the SARs. 

7.4.3 For Cause. If the Participant is Terminated for Cause, the Participant may exercise such Participant’s SARs, but not to an
extent greater than such SARs are exercisable as to Vested Shares upon the Termination Date and Participant’s SARs shall expire on such Participant’s Termination Date, or at such later time and on such conditions as are determined by the
Committee. 
 8. PAYMENT FOR PURCHASES AND EXERCISES. 

8.1 Payment in General. Payment for Shares acquired pursuant to this Plan may be made in cash equivalents
(including by check or Automated Clearing House (“ACH”) transfer) or, where expressly approved for the Participant by the Committee and subject to compliance with applicable law: 

(a) by cancellation of indebtedness of the Company owed to the Participant; 

(b) by surrender of shares of the Company that are clear of all liens, claims, encumbrances or security interests and: (i) for which the
Company has received “full payment of the purchase price” within the meaning of SEC Rule 144 (and, if such shares were purchased from the Company by use of a promissory note, such note has been fully paid with respect to such shares)
or (ii) that were obtained by Participant in the public market; 

  
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 (c) by tender of a full recourse promissory note having such terms as may be approved by
the Committee and bearing interest at a rate sufficient to avoid (i) imputation of income under Sections 483 and 1274 of the Code and (ii) unfavorable accounting treatment as determined by the Committee; provided,
however, that Participants who are not employees or directors of the Company will not be entitled to purchase Shares with a promissory note unless the note is adequately secured by collateral other than the Shares;
provided, further, that the portion of the Exercise Price or Purchase Price, as the case may be, equal to the par value (if any) of the Shares must be paid in cash or other legal consideration permitted by the laws under
which the Company is then incorporated or organized; 
 (d) by waiver of compensation due or accrued to the Participant from the Company
for services rendered; 
 (e) by participating in a formal cashless exercise program implemented by the Committee in connection with the
Plan; 
 (f) provided that a public market for the Company’s common stock exists, by exercising through a “same day sale”
commitment from the Participant and a broker-dealer whereby the Participant irrevocably elects to exercise the Award and to sell a portion of the Shares so purchased sufficient to pay the total Exercise Price or Purchase Price, and whereby the
broker-dealer irrevocably commits upon receipt of such Shares to forward the total Exercise Price or Purchase Price directly to the Company; or 

(g) by any combination of the foregoing or any other method of payment approved by the Committee. 

For avoidance of uncertainty: ACH transfers that have been received by the Company into its bank account designated for receipt of such transfers under this
Section 8.1 shall be deemed to have been received for all purposes under this Plan as of the date on which such transfers were initiated from the transferor’s account and made irrevocable by the transferor. 

8.2 Withholding Taxes. 

8.2.1 Withholding Generally. Whenever Shares are to be issued in satisfaction of Awards granted under this Plan, the Company may
require the Participant to remit to the Company an amount sufficient to satisfy the maximum tax withholding requirements as to income tax, social insurance, payroll tax, fringe benefits tax, payment on account and other tax-related obligations (collectively, “Tax-Related Obligations”) prior to the delivery of any written or electronic certificate or certificates for
such Shares. Whenever, under this Plan, payments in satisfaction of Awards are to be made in cash by the Company, such payment will be net of an amount sufficient to satisfy applicable tax withholding requirements. 

8.2.2 Stock Withholding. When, under applicable tax laws, a Participant incurs tax liability in connection with the exercise or
vesting of any Award that is subject to tax withholding and the Participant is obligated to pay the Company the amount required to be withheld, the Committee may in its sole discretion allow the Participant to satisfy up to the maximum Tax-Related Obligations in the employee’s applicable jurisdictions by electing to have the Company withhold from the Shares to be issued up to the number of Shares having a Fair Market Value on the date that
the amount of tax to be withheld is to be determined that is not more than the maximum Tax-Related Obligations in the employee’s applicable jurisdictions; or to arrange a mandatory “sell to
cover” on Participant’s behalf (without further authorization) but in no event will the Company withhold Shares or “sell to cover” if such withholding would result in adverse accounting or compliance consequences to the Company.
The maximum Tax-Related Obligations are based on the applicable rates of the relevant tax authorities (for example, federal, state and local), including the employee’s share of payroll or similar taxes,
as provided in the tax law, regulations or the authority’s administrative practices, not to exceed the highest statutory rate in that jurisdiction. Any elections to have Shares withheld or sold for this purpose will be made in accordance with
the requirements established by the Committee for such elections and be in writing in a form acceptable to the Committee. 

  
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 8.2.3 Elections Under Section 83(i) of the Code. A Participant
will not make an election under Section 83(i) of the Code if the Company determines that the Participant is then ineligible to make such an election under applicable law or without the Company’s prior written consent (which will not be
unreasonably withheld or delayed, but may be conditioned upon the Participant’s entry into additional commitments as determined by the Company). 

9. RESTRICTIONS ON AWARDS. 

9.1 Transferability. Except as permitted by the Committee, Awards granted under this Plan, and any interest
therein, will not be transferable or assignable by Participant, other than by will or by the laws of descent and distribution, and, with respect to NQSOs for Participants in the U.S., by instrument to an inter vivos or testamentary trust in which
the NQSOs are to be passed to beneficiaries upon the death of the trustor (settlor), or by gift to “family member” as that term is defined in Rule 701, and may not be made subject to execution, attachment or similar process. For the
avoidance of doubt, the prohibition against assignment and transfer applies to Awards and any Shares underlying the Awards prior to the issuance of the Shares, and pursuant to the foregoing sentence shall be understood to include, without
limitation, a prohibition against any pledge, hypothecation, or other transfer, including any short position, any “put equivalent position” or any “call equivalent position” (in each case, as defined in Rule 16a-1 promulgated under the Exchange Act). Unless an Award is transferred pursuant to the terms of this Section, during the lifetime of the Participant an Award will be exercisable only by the Participant or
Participant’s legal representative and any elections with respect to an Award may be made only by the Participant or Participant’s legal representative. The terms of an Award shall be binding upon the executor, administrator, successors
and assigns of the Participant who is a party thereto. 
 9.2 Securities Law and Other Regulatory Compliance.
Although this Plan is intended to be a written compensatory benefit plan within the meaning of Rule 701 promulgated under the Securities Act, Awards may be made pursuant to this Plan that do not qualify for exemption under Rule 701. An Award
will not be effective unless such Award is in compliance with all applicable U.S. and non-U.S. federal, state and local securities laws, rules and regulations of any governmental body, and the requirements of
any stock exchange or automated quotation system upon which the Company’s equity securities may then be listed or quoted, as they are in effect on the date of grant of the Award and also on the date of exercise, settlement or other issuance.
Notwithstanding any other provision in this Plan, the Company will have no obligation to issue Shares or deliver certificates for Shares under this Plan prior to (a) obtaining any approvals from governmental agencies that the Company determines
are necessary or advisable, and/or (b) compliance with any exemption, completion of any registration or other qualification of such Shares under any U.S. and non-U.S. federal, state or local law or ruling
of any governmental body that the Company determines to be necessary or advisable. The Company will be under no obligation to register the Shares with the SEC or to effect compliance with the exemption, registration, qualification or listing
requirements of any securities laws, stock exchange or automated quotation system, and the Company will have no liability for any inability or failure to do so. 

9.3 Exchange and Buyout of Awards. The Committee may, at any time or from time to time, authorize the Company,
with the consent of the respective Participants, to issue new Awards in exchange for the surrender and cancellation of any or all outstanding Awards. Without prior stockholder approval the Committee may reprice Options or SARs (and where such
repricing is a reduction in the Exercise Price of outstanding Options or SARs, the consent of the affected Participants is not required provided written notice is provided to them). The Committee may at any time buy from a Participant an Award
previously granted with payment in cash, Shares (including Restricted Stock) or other consideration, based on such terms and conditions as the Committee and the Participant may agree. 

  
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 10. RESTRICTIONS ON SHARES. 

10.1 Privileges of Stock Ownership. No Participant will have any of the rights of a stockholder with respect to
any Shares until such Shares are issued to the Participant. After Shares are issued to the Participant, the Participant will be a stockholder and have all the rights of a stockholder with respect to such Shares, including the right to vote and
receive all dividends or other distributions made or paid with respect to such Shares; provided, that if such Shares are Restricted Stock, then any new, additional or different securities the Participant may become entitled to receive
with respect to such Shares by virtue of a stock dividend, stock split or any other change in the corporate or capital structure of the Company will be subject to the same restrictions as the Restricted Stock. The Participant will have no right to
retain such stock dividends or stock distributions with respect to Unvested Shares that are repurchased as described in this Section 10. 

10.2 Rights of First Refusal and Repurchase. At the discretion of the Committee, the Company may reserve to itself
and/or its assignee(s) in the Award Agreement (a) a right of first refusal to purchase all Shares that a Participant (or a subsequent transferee) may propose to transfer to a third party, provided that such right of first refusal
terminates upon (i) subject to any applicable market standoff restrictions, the effective date of the first sale of common stock of the Company to the general public pursuant to a registration statement filed with and declared effective
by the SEC under the Securities Act (other than a registration statement relating solely to the issuance of common stock pursuant to a business combination or an employee incentive or benefit plan); (ii) any transfer or conversion of Shares made
pursuant to a statutory merger or statutory consolidation of the Company with or into another corporation or corporations if the common stock of the surviving corporation or any direct or indirect Parent thereof is registered under the
Exchange Act; or (iii) any transfer or conversion of Shares made pursuant to a statutory conversion of the Company into another form of legal entity if the common equity (or comparable equity security) of entity resulting from such
conversion is registered under the Exchange Act; and (b) a right to repurchase Unvested Shares held by a Participant for cash and/or cancellation of purchase money indebtedness owed to the Company by the Participant following such
Participant’s Termination at any time. 
 10.3 Agreement to Vote Shares. At the discretion of the
Committee, the Company may require that, as a condition to the receipt of the Shares upon issuance of an Award, exercise of an Option or SAR or settlement of an RSU, the Participant and any transferee of the Shares agree to vote such Shares pursuant
to the terms of a Voting Agreement by and between the Company and certain of its stockholders. 
 10.4 Escrow; Pledge of
Shares. To enforce any restrictions on a Participant’s Shares, the Committee may require the Participant to deposit all written or electronic certificates representing Shares, together with stock powers or other instruments of
transfer approved by the Committee, appropriately endorsed in blank, with the Company or an agent designated by the Company to hold in escrow until such restrictions have lapsed or terminated. The Committee may cause a legend or legends referencing
such restrictions to be placed on the written or electronic certificate. Any Participant who is permitted to execute a promissory note as partial or full consideration for the purchase of Shares under this Plan will be required to pledge and deposit
with the Company all or part of the Shares so purchased as collateral to secure the payment of Participant’s obligation to the Company under the promissory note; provided, however, that the Committee may require or
accept other or additional forms of collateral to secure the payment of such obligation and, in any event, the Company will have full recourse against the Participant under the promissory note notwithstanding any pledge of the Participant’s
Shares or other collateral. In connection with any pledge of the Shares, Participant will be required to execute and deliver a written pledge agreement in such form as the Committee will from time to time approve. The Shares purchased with the
promissory note may be released from the pledge on a pro rata basis as the promissory note is paid. 

  
 9 

 10.5 Securities Law Restrictions. All written or electronic
certificates for Shares or other securities delivered under this Plan will be subject to such stock transfer orders, legends and other restrictions as the Committee may deem necessary or advisable, including restrictions under any applicable U.S.
and non-U.S. federal, state or local securities law, or any rules, regulations and other requirements of the SEC or any stock exchange or automated quotation system upon which the Company’s equity
securities may be listed or quoted. 
 11. CORPORATE TRANSACTIONS. 

11.1 Acquisitions or Other Combinations. In the event that the Company is subject to an Acquisition or Other
Combination, outstanding Awards acquired under the Plan shall be subject to the agreement evidencing the Acquisition or Other Combination, which need not treat all outstanding Awards in an identical manner. Such agreement, without the
Participant’s consent, shall provide for one or more of the following with respect to all outstanding Awards as of the effective date of such Acquisition or Other Combination: 

(a) The continuation of such outstanding Awards by the Company (if the Company is the successor entity). 

(b) The assumption of outstanding Awards by the successor or acquiring entity (if any) in such Acquisition or Other Combination (or by any of
its Parents, if any), which assumption, will be binding on all Participants; provided that the exercise price and the number and nature of shares issuable upon exercise of any such option or stock appreciation right, or upon the settlement of any
award that is subject to Section 409A of the Code, will be adjusted appropriately pursuant to Section 424(a) and Section 409A of the Code. For the purposes of this Section 11, an Award will be considered assumed if, following the
Acquisition or Other Combination, the Award confers the right to purchase or receive, for each Share subject to the Award immediately prior to the Acquisition or Other Combination, the consideration (whether stock, cash, or other securities or
property) received in the Acquisition or Other Combination by holders of Shares for each Share held on the effective date of the transaction (and if holders were offered a choice of consideration, the type of consideration chosen by the holders of a
majority of the outstanding Shares); provided, however, that if such consideration received in the Acquisition or Other Combination is not solely common stock of the successor corporation or its Parent, the Committee may, with the consent of the
successor corporation, provide for the consideration to be received upon the exercise of an Option or Stock Appreciation Right or upon the settlement of an RSU, for each Share subject to such Award, to be solely common stock of the successor
corporation or its Parent equal in fair market value to the per share consideration received by holders of Common Stock in the Acquisition or Other Combination. 

(c) The substitution by the successor or acquiring entity in such Acquisition or Other Combination (or by any of its Parents, if any) of
equivalent awards with substantially the same terms for such outstanding Awards (except that the exercise price and the number and nature of shares issuable upon exercise of any such option or stock appreciation right, or any award that is subject
to Section 409A of the Code, will be adjusted appropriately pursuant to Section 424(a) and Section 409A of the Code). 
 (d)
The full or partial exercisability or vesting and accelerated expiration of outstanding Awards. 
 (e) The settlement of the Fair Market
Value of such outstanding Award (whether or not then vested or exercisable) in cash, cash equivalents, or securities of the successor entity (or its Parent, if any), followed by the cancellation of such Awards; provided however, that such Award may
be cancelled without consideration if such Award has no value, as determined by the Committee, in its discretion. Subject to Section 409A of the Code, such payment may be made in installments and may be deferred until the date or dates when the
Award would have become exercisable or vested. Such payment may be subject to vesting based on the Participant’s continued service, provided that without the Participant’s consent, the vesting schedule shall not be less favorable to the
Participant than the schedule under which the Award would have become vested or exercisable. For purposes of this Section 11.1(e), the Fair Market Value of any security shall be determined without regard to any vesting conditions that may apply
to such security. 

  
 10 

 (f) The termination in its entirety of any outstanding Award, without payment of any
consideration, that is not exercised in accordance with its terms upon or prior to consummation of the transactions contemplated by the Acquisition or Other Combination within a time specified by the Committee, in its discretion, for such exercise,
whether or not such Award is then fully exercisable. 
 Immediately following an Acquisition or Other Combination, outstanding Awards shall
terminate and cease to be outstanding, except to the extent such Awards, have been continued, assumed or substituted, as described in Sections 11.1(a), (b) and/or (c). 

11.2 Substitution or Assumption of Awards by the Company. The Company, from time to time, also may substitute or
assume outstanding awards granted by another entity, whether in connection with an acquisition of such other entity or otherwise, by either (a) granting an Award under this Plan in substitution of such other entity’s award or
(b) assuming and/or converting such award as if it had been granted under this Plan if the terms of such assumed award could be applied to an Award granted under this Plan. Such substitution or assumption will be permissible if the holder of
the substituted or assumed award would have been eligible to be granted an Award under this Plan if the other entity had applied the rules of this Plan to such grant. In the event the Company assumes an award granted by another entity, the terms and
conditions of such award will remain unchanged (except that the exercise price and the number and nature of shares issuable upon exercise of any such option or stock appreciation right, or any award that is subject to Section 409A of the Code,
will be adjusted appropriately pursuant to Section 424(a) or Section 409A of the Code). In the event the Company elects to grant a new Option or SAR in substitution for and rather than assuming an existing option or stock appreciation
right, such new Option or SAR may be granted with a similarly adjusted Exercise Price and number of underlying Shares and such other changes approved by the Committee, subject to the consent of the Participant. 

12. ADMINISTRATION. 

12.1 Committee Authority. This Plan will be administered by the Committee. Subject to the general purposes, terms
and conditions of this Plan, and to the direction of the Board, the Committee will have full power to implement and carry out this Plan. Without limitation, the Committee will have the authority to: 

(a) construe and interpret this Plan, any Award Agreement and any other agreement or document executed pursuant to this Plan; 

(b) prescribe, amend, expand, modify and rescind or terminate rules and regulations relating to this Plan; 

(c) approve persons to receive Awards; 

(d) determine the form and terms of Awards; 

(e) determine the number of Shares or other consideration subject to Awards granted under this Plan; 

(f) determine the Fair Market Value in good faith and interpret the applicable provisions of this Plan and the definition of Fair Market
Value in connection with circumstances that impact the Fair Market Value, if necessary; 

  
 11 

 (g) determine whether Awards will be granted singly, in combination with, in tandem with,
in replacement of, or as alternatives to, other Awards under this Plan or awards under any other incentive or compensation plan of the Company or any Parent or Subsidiary of the Company; 

(h) grant waivers of any conditions of this Plan or any Award; 

(i) determine the terms of vesting, exercisability, settlement and payment of Awards to be granted pursuant to this Plan; 

(j) correct any defect, supply any omission, or reconcile any inconsistency in this Plan, any Award, any Award Agreement or any Exercise
Agreement; 
 (k) determine whether an Award has vested or become exercisable; 

(l) extend the vesting period beyond a Participant’s Termination Date; 

(m) adopt rules and/or procedures (including the adoption of any subplan under this Plan) relating to the operation and administration of the
Plan to accommodate or facilitate requirements of local law and procedures outside of the United States; 
 (n) delegate any of the
foregoing to a subcommittee consisting of one or more directors or executive officers pursuant to a specific delegation as may otherwise be permitted by applicable law; 

(o) change the vesting schedule of Awards under the Plan prospectively in the event that the Participant’s service status changes
between full and part time status in accordance with Company policies relating to work schedules and vesting of Awards; and 
 (p) make all
other determinations necessary or advisable in connection with the administration of this Plan. 
 12.2 Standalone, Tandem and
Substitute Awards. Awards granted under the Plan may, in the sole discretion of the Committee, be granted either alone or in addition to, in tandem with, or in substitution for, any other Award granted under the Plan. Awards granted
in addition to or in tandem with other Awards may be granted either at the same time as or at a different time from the grant of such other Awards. 

12.3 Committee Composition and Discretion. The Board may delegate full administrative authority over the Plan and
Awards to a Committee consisting of at least one member of the Board (or such greater number as may then be required by applicable law). Unless in contravention of any express terms of this Plan or Award, any determination made by the
Committee with respect to any Award will be made in its sole discretion either (a) at the time of grant of the Award, or (b) subject to Section 4.9 hereof, at any later time. Any such determination will be final and binding on the
Company and on all persons having an interest in any Award under this Plan. To the extent permitted by applicable law, the Committee may delegate to one or more directors or officers of the Company the authority to grant an Award under this Plan.

 12.4 Nonexclusivity of the Plan. Neither the adoption of this Plan by the Board, the submission of this Plan
to the stockholders of the Company for approval, nor any provision of this Plan will be construed as creating any limitations on the power of the Board to adopt such additional compensation arrangements as it may deem desirable, including, without
limitation, the granting of stock options and other equity awards otherwise than under this Plan, and such arrangements may be either generally applicable or applicable only in specific cases. 

  
 12 

 12.5 Governing Law. This Plan and all agreements hereunder shall
be governed by and construed in accordance with the laws of the State of Delaware, without giving effect to that body of laws pertaining to conflict of laws. 

13. EFFECTIVENESS, AMENDMENT AND TERMINATION OF THE PLAN. 

13.1 Adoption and Stockholder Approval. This Plan will become effective on the date that it is adopted by the
Board (the “Effective Date”). This Plan will be approved by the stockholders of the Company (excluding Shares issued pursuant to this Plan), consistent with applicable laws, within twelve (12) months before or after the
Effective Date. Upon the Effective Date, the Committee may grant Awards pursuant to this Plan; provided, however, that: (a) no Option or SAR may be exercised prior to initial stockholder approval of this Plan; and
(b) no Option or SAR granted pursuant to an increase in the number of Shares approved by the Board shall be exercised prior to the time such increase has been approved by the stockholders of the Company. 

13.2 Term of Plan. Unless earlier terminated as provided herein, this Plan will automatically terminate ten
(10) years after the Effective Date. 
 13.3 Amendment or Termination of Plan. Subject to Section 4.9
hereof, the Board may at any time (a) terminate or amend this Plan in any respect, including without limitation amendment of any form of Award Agreement or instrument to be executed pursuant to this Plan and (b) terminate any and all
outstanding Options, SARs or RSUs upon a dissolution or liquidation of the Company, followed by the payment of creditors and the distribution of any remaining funds to the Company’s stockholders; provided, however,
that the Board will not, without the approval of the stockholders of the Company, amend this Plan in any manner that requires such stockholder approval pursuant to the Code or the regulations promulgated under the Code as such provisions apply to
ISO plans. The termination of the Plan, or any amendment thereof, shall not affect any Share previously issued or any Award previously granted under the Plan. 

14. DEFINITIONS. For all purposes of this Plan, the following terms will have the following meanings. 

“Acquisition,” for purposes of Section 11, means: 

(a) any consolidation or merger in which the Company is a constituent entity or is a party in which the voting stock and other voting
securities of the Company that are outstanding immediately prior to the consummation of such consolidation or merger represent, or are converted into, securities of the surviving entity of such consolidation or merger (or of any Parent of such
surviving entity) that, immediately after the consummation of such consolidation or merger, together possess less than fifty percent (50%) of the total voting power of all voting securities of such surviving entity (or of any of its Parents, if any)
that are outstanding immediately after the consummation of such consolidation or merger; 
 (b) a sale or other transfer by the holders
thereof of outstanding voting stock and/or other voting securities of the Company possessing more than fifty percent (50%) of the total voting power of all outstanding voting securities of the Company, whether in one transaction or in a series of
related transactions, pursuant to an agreement or agreements to which the Company is a party and that has been approved by the Board, and pursuant to which such outstanding voting securities are sold or transferred to a single person or entity, to
one or more persons or entities who are Affiliates of each other, or to one or more persons or entities acting in concert; or 

  
 13 

 (c) the sale, lease, transfer or other disposition, in a single transaction or series of
related transactions, by the Company and/or any Subsidiary or Subsidiaries of the Company, of all or substantially all the assets of the Company and its Subsidiaries taken as a whole (or, if substantially all of the assets of the Company and its
Subsidiaries taken as a whole are held by one or more Subsidiaries, the sale or disposition (whether by consolidation, merger, conversion or otherwise) of such Subsidiaries of the Company), except where such sale, lease, transfer or other
disposition is made to the Company or one or more wholly owned Subsidiaries of the Company. 
 Notwithstanding the foregoing, the following transactions
shall not constitute an “Acquisition”: (1) the closing of the Company’s first public offering pursuant to an effective registration statement filed under the Securities Act or (2) any transaction the sole purpose of which is to
change the state of incorporation of the Company or to create a holding company that will be owned in substantially the same proportions by the persons who held the Company’s securities immediately before such transaction. 

“Affiliate” of a specified person means a person that directly, or indirectly through one or more
intermediaries, controls or is controlled by, or is under common control with, the person specified (where, for purposes of this definition, the term “control” (including the terms
“controlling,” “controlled by” and “under common control with”) means the possession, direct or indirect, of the power to direct or cause the direction of the management and
policies of a person, whether through the ownership of voting securities, by contract, or otherwise. 
 “Award”
means any award pursuant to the terms and conditions of this Plan, including any Option, Restricted Stock Unit, Stock Appreciation Right or Restricted Stock Award. 

“Award Agreement” means, with respect to each Award, the executed written or electronic agreement between the Company
and the Participant setting forth the terms and conditions of the Award as approved by the Committee. For purposes of the Plan, the Award Agreement may be accepted by a Participant via written, electronic or other means, subject to requirements
under applicable law. 
 “Board” means the Board of Directors of the Company. 

“Cause” means Termination because of (a) Participant’s unauthorized misuse of the Company or a Parent or
Subsidiary of the Company’s trade secrets or proprietary information, (b) Participant’s conviction of or plea of nolo contendere to a felony or a crime involving moral turpitude, (c) Participant’s committing an act of fraud
against the Company or a Parent or Subsidiary of the Company or (d) Participant’s gross negligence or willful misconduct in the performance of his or her duties that has had or will have a material adverse effect on the Company or Parent
or Subsidiary of the Company’ reputation or business. 
 “Code” means the U.S. Internal Revenue Code of 1986,
as amended. 
 “Committee” means the committee created and appointed by the Board to administer this Plan, or if no
committee is created and appointed, the Board. 
 “Company” means Prelude Therapeutics Incorporated, a Delaware
corporation, or any successor corporation. 
 “Disability” means a Participant is unable to perform the duties of
his or her customary position of employment by reason of any medically determinable physical or mental impairment that can be expected to result in death or that can be expected to last for a continuous period of not less than twelve
(12) months. The Committee may require such medical or other evidence as it deems necessary to judge the nature and permanency of the Participant’s condition. 

“Exchange Act” means the U.S. Securities Exchange Act of 1934, as amended. 

“Exercise Price” means the price per Share at which a holder of an Option or a SAR may purchase Shares issuable upon
exercise of the Option or the SAR. 

  
 14 

 “Fair Market Value” means, as of any date, the value of a Share
determined as follows: 
 (a) if such Share is then publicly traded on a national securities exchange, its closing price on the date of
determination on the principal national securities exchange on which the Share is listed or admitted to trading as reported in The Wall Street Journal; 

(b) if such Share is publicly traded but is not listed or admitted to trading on a national securities exchange, the average of the closing
bid and ask prices on the date of determination as reported by The Wall Street Journal (or as otherwise reported by any newspaper or other source as the Committee may determine); or 

(c) if none of the foregoing is applicable to the valuation in question, by the Committee in good faith. 

“Option” means an award of an option to purchase Shares pursuant to Section 4 of this Plan. 

“Other Combination” for purposes of Section 11 means any (a) consolidation or merger in which the Company is
a constituent entity and is not the surviving entity of such consolidation or merger or (b) any conversion of the Company into another form of entity; provided that such consolidation, merger or conversion does not constitute an
Acquisition. 
 “Parent” of a specified entity means, any entity that, either directly or indirectly, owns or
controls such specified entity, where for this purpose, “control” means the ownership of stock, securities or other interests that possess at least a majority of the voting power of such specified entity (including indirect
ownership or control of such stock, securities or other interests). 
 “Participant” means a person who receives an
Award under this Plan. 
 “Plan” means this Amended and Restated 2016 Stock Incentive Plan, as amended from time to
time. 
 “Purchase Price” means the price at which a Participant may purchase Restricted Stock pursuant to this
Plan. 
 “Restricted Stock” means Shares purchased pursuant to a Restricted Stock Award under this Plan. 

“Restricted Stock Award” means an award of Shares pursuant to Section 5 hereof. 

“Restricted Stock Unit” or “RSU” means an award made pursuant to Section 6 hereof. 

“Rule 701” means Rule 701 et seq. promulgated by the SEC under the Securities Act. 

“SEC” means the U.S. Securities and Exchange Commission. 

“Securities Act” means the U.S. Securities Act of 1933, as amended. 

“Shares” means shares of the Company’s Common Stock, $0.0001 par value per share, reserved for issuance under
this Plan, as adjusted pursuant to Sections 2.2 and 11 hereof, and any successor security. 
 “Stock Appreciation
Right” or “SAR” means an award granted pursuant to Section 7 hereof. 

  
 15 

 “Subsidiary” means any entity (other than the Company) in an
unbroken chain of entities beginning with the Company if each of the entities other than the last entity in the unbroken chain owns stock or other equity securities representing fifty percent (50%) or more of the total combined voting power of all
classes of stock or other equity securities in one of the other entities in such chain. 
 “Termination” or
“Terminated” means, for purposes of this Plan with respect to a Participant, that the Participant has for any reason ceased to provide services as an employee, officer, director or consultant to the Company or a Parent or
Subsidiary of the Company. A Participant will not be deemed to have ceased to provide services while the Participant is on a bona fide leave of absence, if such leave was approved by the Company in writing. In the case of an approved leave of
absence, the Committee may make such provisions respecting crediting of service, including suspension of vesting of the Award (including pursuant to a formal policy adopted from time to time by the Company) it may deem appropriate. The Committee
will have sole discretion to determine whether a Participant has ceased to provide services and the effective date on which the Participant ceased to provide services (the “Termination Date”). 

“Unvested Shares” means “Unvested Shares” as defined in the Award Agreement for an Award. 

“Vested Shares” means “Vested Shares” as defined in the Award Agreement for an Award. 

* * * * * * * * * * * 

  
 16 

 EARLY EXERCISE FORM 

OPTION GRANT NO. ___ 

NOTICE OF STOCK OPTION GRANT 

PRELUDE THERAPEUTICS INCORPORATED 

2016 STOCK INCENTIVE PLAN 

The Optionee named below (“Optionee”) has been granted an option (this “Option”) to purchase shares of Common
Stock, $0.0001 par value per share (the “Common Stock”), of Prelude Therapeutics Incorporated, a Delaware corporation (the “Company”), pursuant to the Company’s 2016 Stock Incentive Plan,
as amended from time to time (the “Plan”) on the terms, and subject to the conditions, described below and in the Stock Option Agreement attached hereto as Exhibit A, including
its annexes (the “Stock Option Agreement”). 
  

			
	Optionee:	  	
		
	Maximum Number of Shares Subject to this Option (the “Shares”):	  	
		
	Exercise Price Per Share:	  	$____ per share
		
	Date of Grant:	  	
		
	Vesting Start Date:	  	
		
	Exercise Schedule:	  	This Option is immediately exercisable for all of the Shares, subject to the terms of the Stock Option Agreement
		
	Expiration Date:	  	The date ten (10) years after the Date of Grant set forth above, subject to earlier expiration in the event of Termination as provided in Section 3 of the Stock Option Agreement.
		
	 Tax Status of Option:
 (Check
Only One Box):
	  	 ☐ Incentive Stock Option (To the fullest extent permitted by the Code)

☐ Nonqualified Stock Option.
 (If
neither box is checked, this Option is a Nonqualified Stock Option).

 Vesting Schedule [EXAMPLE ONLY]: For so long as Optionee continuously provides services to the Company (or any
Subsidiary or Parent of the Company) as an employee, officer, director, contractor or consultant, the Shares subject to this Option will vest as follows: (a) prior to the first one (1) year anniversary of the Vesting Start Date, none of
the Shares will be vested; (b) [1/4th] of the Shares will be vested on the one (1) year anniversary of the Vesting Start Date; and (c) thereafter, this Option
will become vested and exercisable with respect to an additional [1/48th] of the Shares when Optionee completes each month of continuous service following the first one
(1) year anniversary of the Vesting Start Date. 
 General; Agreement: By their signatures below, Optionee and the Company agree that this
Option is granted under and governed by this Notice of Stock Option Grant (this “Grant Notice”) and by the provisions of the Plan and the Stock Option Agreement. The Plan and the Stock Option Agreement are incorporated herein
by reference. Capitalized terms used but not defined herein shall have the meanings given to them in the Plan or in the Stock Option Agreement, as applicable. By signing below, Optionee acknowledges receipt of a copy of this Grant Notice, the Plan
and the Stock Option Agreement, represents that Optionee has carefully read and is familiar with their provisions, and hereby accepts the Option subject to all of their respective terms and conditions. Optionee acknowledges that there may be adverse
tax consequences upon exercise of the Option or disposition of the Shares and that Optionee should consult a tax adviser prior to such exercise or disposition. Optionee agrees and acknowledges that the Vesting Schedule may change prospectively in
the event that Optionee’s service status changes between full and part time status in accordance with Company policies relating to work schedules and vesting of equity awards. 

Execution and Delivery: This Grant Notice may be executed and delivered electronically whether via the Company’s intranet or the Internet site of
a third party or via email or any other means of electronic delivery specified by the Company. By Optionee’s acceptance hereof (whether written, electronic or otherwise), Optionee agrees, to the fullest extent permitted by law, that in lieu of
receiving documents in paper format, Optionee accepts the electronic delivery of any documents that the Company (or any third party the Company may designate), may deliver in connection with this grant (including the Plan, this Grant Notice, the
Stock Option Agreement, the information described in Rules 701(e)(2), (3), (4) and (5) under the Securities Act (the “701 Disclosures”), account statements, or other communications or information) whether via the
Company’s intranet or the Internet site of such third party or via email or such other means of electronic delivery specified by the Company. 
  

			
	PRELUDE THERAPEUTICS INCORPORATED	  	
		
	By
/Signature:                                       
                             	  	Optionee
Signature:                                       
     
	Typed
Name:                                        
                              	  	Optionee’s
Name:                                        
       
	Title:                                     
                                         
     	  	
	ATTACHMENT:     Exhibit A – Stock Option Agreement	  	

 Exhibit A 

Stock Option Agreement 

 EXHIBIT A 

EARLY EXERCISE FORM 

STOCK OPTION AGREEMENT 

PRELUDE THERAPEUTICS INCORPORATED 

2016 STOCK INCENTIVE PLAN 

This Stock Option Agreement (this “Agreement”) is made and entered into as of the date of grant (the “Date
of Grant”) set forth on the Notice of Stock Option Grant attached as the facing page to this Agreement (the “Grant Notice”) by and between Prelude Therapeutics Incorporated, a Delaware corporation (the
“Company”), and the optionee named on the Grant Notice (“Optionee”). Capitalized terms not defined in this Agreement shall have the meaning ascribed to them in the Company’s 2016 Stock Incentive
Plan, as amended from time to time (the “Plan”), or in the Grant Notice, as applicable. 
 1. GRANT
OF OPTION. The Company hereby grants to Optionee an option (this “Option”) to purchase up to the total number of shares of Common Stock of the Company, $0.0001 par value per share (the “Common
Stock”), set forth in the Grant Notice as the Shares (the “Shares”) at the Exercise Price Per Share set forth in the Grant Notice (the “Exercise Price”), subject to all of the terms and
conditions of the Grant Notice, this Agreement and the Plan. If designated as an Incentive Stock Option in the Grant Notice, this Option is intended to qualify as an incentive stock option (the “ISO”) within the meaning of
Section 422 of the Internal Revenue Code of 1986, as amended (the “Code”), except that if on the Date of Grant Optionee is not subject to U.S. income tax, then this Option shall be a NQSO. 

2. EXERCISE PERIOD. 

2.1. Exercise Period of Option. Subject to the conditions set forth in this Agreement, all or part of this Option
may be exercised at any time after the Date of Grant. Shares purchased by exercising this Option may be subject to the Repurchase Option as set forth in Section 7 below. This Option will become vested during its term as to portions of the
Shares in accordance with the Vesting Schedule set forth in the Grant Notice. Notwithstanding any provision in the Plan or this Agreement to the contrary, on or after Optionee’s Termination Date, this Option may not be exercised with respect to
any Shares that are Unvested Shares on Optionee’s Termination Date. 
 2.2. Vesting of Option Shares.
Shares with respect to which this Option is vested at a given time pursuant to the Vesting Schedule set forth in the Grant Notice are “Vested Shares.” Shares with respect to which this Option is not vested at a given
time pursuant to the Vesting Schedule set forth in the Grant Notice are “Unvested Shares.” 

2.3. Expiration. The Option shall expire on the Expiration Date set forth in the Grant Notice or earlier as
provided in Section 3 below. 
 3. TERMINATION. 

3.1. Termination for Any Reason Except Death, Disability or Cause. Except as provided in subsection 3.2 in a case
in which Optionee dies within three (3) months after Optionee is Terminated other than for Cause, if Optionee is Terminated for any reason (other than Optionee’s death or Disability or for Cause), then (a) on and after
Optionee’s Termination Date, this Option shall expire immediately with respect to any Shares that are Unvested Shares and may not be exercised with respect to any Shares that are Unvested Shares on Optionee’s Termination Date and
(b) this Option to the extent (and only to the extent) that it is exercisable with respect to Vested Shares on Optionee’s Termination Date, may be exercised by Optionee no later than three (3) months after Optionee’s
Termination Date (but in no event may this Option be exercised after the Expiration Date). 
  

 3.2. Termination Because of Death or Disability. If Optionee is
Terminated because of Optionee’s death or Disability (or if Optionee dies within three (3) months of the date of Optionee’s Termination for any reason other than for Cause), then (a) on and after Optionee’s Termination Date,
this Option shall expire immediately with respect to any Shares that are Unvested Shares and may not be exercised with respect to any Shares that are Unvested Shares on Optionee’s Termination Date and (b) this Option, to the extent (and
only to the extent) that it is exercisable with respect to Vested Shares on Optionee’s Termination Date, may be exercised by Optionee (or Optionee’s legal representative) no later than twelve (12) months after Optionee’s
Termination Date, but in no event later than the Expiration Date. Any exercise of this Option beyond (i) three (3) months after the date Optionee ceases to be an employee when Optionee’s Termination is for any reason other than
Optionee’s death or disability, within the meaning of Section 22(e)(3) of the Code; or (ii) twelve (12) months after the date Optionee ceases to be an employee when the termination is for Optionee’s disability, within the
meaning of Section 22(e)(3) of the Code, is deemed to be an NQSO. 
 3.3. Termination for Cause. If
Optionee is Terminated for Cause, then Optionee may exercise this Option, but only with respect to any Shares that are Vested Shares on Optionee’s Termination Date, and this Option shall expire on Optionee’s Termination Date, or at
such later time and on such conditions as may be affirmatively determined by the Committee. On and after Optionee’s Termination Date, this Option shall expire immediately with respect to any Shares that are Unvested Shares and may not be
exercised with respect to any Shares that are Unvested Shares on Optionee’s Termination Date. 
 3.4. No Obligation to
Employ. Nothing in the Plan or this Agreement shall confer on Optionee any right to continue in the employ of, or other relationship with, the Company or any Parent or Subsidiary of the Company, or limit in any way the right of the
Company or any Parent or Subsidiary of the Company to terminate Optionee’s employment or other relationship at any time, with or without Cause. 

4. MANNER OF EXERCISE. 

4.1. Stock Option Exercise Notice and Agreement. To exercise this Option, Optionee (or in the case of exercise
after Optionee’s death or incapacity, Optionee’s executor, administrator, heir or legatee, as the case may be) must deliver to the Company an executed Stock Option Exercise Notice and Agreement in the form attached hereto as
Annex A, or in such other form as may be approved by the Committee from time to time (the “Exercise Agreement”) and payment for the shares being purchased in accordance with this
Agreement. The Exercise Agreement shall set forth, among other things, (i) Optionee’s election to exercise this Option, (ii) the number of Shares being purchased, (iii) any representations, warranties and agreements regarding
Optionee’s investment intent and access to information as may be required by the Company to comply with applicable securities laws in connection with any exercise of this Option and (iv) any other agreements required by the Company. If
someone other than Optionee exercises this Option, then such person must submit documentation reasonably acceptable to the Company verifying that such person has the legal right to exercise this Option and such person shall be subject to all of the
restrictions contained herein as if such person were Optionee. 
 4.2. Limitations on Exercise. This Option may
not be exercised unless such exercise is in compliance with all applicable federal and state securities laws, as they are in effect on the date of exercise. 

4.3. Payment. The Exercise Agreement shall be accompanied by full payment of the Exercise Price for the shares
being purchased in cash (by check, Automated Clearing House (“ACH”) or wire transfer), or where permitted by law: 

(a) by cancellation of indebtedness of the Company owed to Optionee; 

(b) by surrender of shares of the Company that are free and clear of all security interests, pledges, liens, claims or encumbrances and:
(i) for which the Company has received “full payment of the purchase price” within the meaning of SEC Rule 144 (and, if such shares were purchased from the Company by use of a promissory note, such note has been fully paid with
respect to such shares) or (ii) that were obtained by Optionee in the public market; 

  
 2 

 (c) by participating in a formal cashless exercise program implemented by the Committee in
connection with the Plan; 
 (d) provided that a public market for the Common Stock exists, subject to compliance with applicable law, by
exercising as set forth below, through a “same day sale” commitment from Optionee and a broker-dealer whereby Optionee irrevocably elects to exercise this Option and to sell a portion of the Shares so purchased sufficient to pay the total
Exercise Price, and whereby the broker-dealer irrevocably commits upon receipt of such Shares to forward the total Exercise Price directly to the Company; or 

(e) by any combination of the foregoing or any other method of payment approved by the Committee that constitutes legal consideration for the
issuance of Shares. 
 For avoidance of uncertainty: ACH transfers that have been received by the Company into its bank account designated for receipt of
such transfers shall be deemed to have been received for all purposes of this Option as of the date on which such transfers were initiated from the Optionee’s account and made irrevocable by Optionee. 

4.4. Tax Withholding. Prior to the issuance of the Shares upon exercise of the Option, Optionee must pay or
provide for foreign, federal, state and local income tax, social insurance, payroll tax, fringe benefits tax, payment on account withholding and other tax-related items related to Optionee’s participation
in the Plan and legally applicable to Optionee, including, as applicable, obligations of the Company (all the foregoing tax-related items, “Tax-Related
Items”). If the Committee permits, Optionee may provide for payment of withholding taxes upon exercise of the Option by requesting that the Company retain the number of Shares with a Fair Market Value equal to the amount of taxes
required to be withheld; or to arrange a mandatory “sell to cover” on Optionee’s behalf (without further authorization); but in no event will the Company withhold Shares or “sell to cover” if such withholding would result in
adverse accounting consequences to the Company. In case of stock withholding or a sell to cover, the Company shall issue the net number of Shares to Optionee by deducting the Shares retained from the Shares issuable upon exercise. The Company may
withhold or account for Tax-Related Items by considering applicable minimum statutory withholding rates or other applicable statutory rates in Optionee’s country, including maximum applicable rates. 

4.5. Issuance of Shares. Provided that the Exercise Agreement and payment are in form and substance satisfactory
to counsel for the Company, the Company shall issue the Shares issuable upon a valid exercise of this Option registered in the name of Optionee, Optionee’s authorized assignee, or Optionee’s legal representative, and shall deliver
certificates representing the Shares with the appropriate legends affixed thereto. 
 5.
COMPLIANCE WITH LAWS AND REGULATIONS. The Plan and this Agreement are intended to comply with Rule 701. Any provision of this Agreement that is inconsistent
with Rule 701 shall, without further act or amendment by the Company or the Committee, be reformed to comply with the requirements of Rule 701. The exercise of this Option and the issuance and transfer of Shares shall be subject to compliance
by the Company and Optionee with all applicable requirements of federal and state securities laws and with all applicable requirements of any stock exchange on which the Common Stock may be listed at the time of such issuance or transfer. Optionee
understands that the Company is under no obligation to register or qualify the Shares with the SEC, any state securities commission or any stock exchange to effect such compliance. 

6. NONTRANSFERABILITY OF OPTION. This Option may not be transferred in any manner
other than by will or by the laws of descent and distribution, and, with respect to NQSOs, by instrument to a testamentary trust in which the options are to be passed to beneficiaries upon the death of the trustor (settlor) or a revocable trust, or
by gift to “immediate family” as that term is defined in 17 C.F.R. 240.16a-1(e), and may be exercised during the lifetime of Optionee only by Optionee or in the event of Optionee’s incapacity,
by Optionee’s legal representative. The terms of this Option shall be binding upon the executors, administrators, successors and assigns of Optionee. 

  
 3 

 7. COMPANY’S REPURCHASE OPTION FOR UNVESTED SHARES. If Optionee is
Terminated for any reason, or no reason, including without limitation, Optionee’s death, Disability, voluntary resignation or termination by the Company with or without Cause and Optionee has acquired Unvested Shares by exercising this Option,
then the Company and/or its assignee(s) shall have the option to repurchase all or a portion of Optionee’s Unvested Shares (as defined in Section 2.2 of this Agreement) as of the Termination Date on the terms and conditions set forth in
this Section 7 (the “Repurchase Option”). 
 7.1. Termination and Termination Date.
In case of any dispute as to whether Optionee is Terminated, the Committee shall have discretion to determine whether Optionee has been Terminated and the effective date of such Termination (the “Termination Date”). 

7.2. Exercise of Repurchase Option. Subject to the foregoing provisions of this Section, at any time within ninety
(90) days after Optionee’s Termination Date, the Company and/or its assignee(s), may elect to repurchase any or all of Optionee’s Unvested Shares by giving Optionee written notice of exercise of the Repurchase Option. 

7.3. Calculation of Repurchase Price for Unvested Shares. The Company or its assignee shall have the option to
repurchase from Optionee (or from Optionee’s personal representative as the case may be) the Unvested Shares at Optionee’s Exercise Price, as such may be proportionately adjusted for any stock split or similar change in the capital
structure of the Company as set forth in Section 2.2 of the Plan (the “Repurchase Price”). 
 7.4.
Payment of Repurchase Price. The Repurchase Price shall be payable, at the option of the Company or its assignee, by check or by cancellation of all or a portion of any outstanding indebtedness owed by Optionee to the
Company and/or such assignee, or by any combination thereof. The Repurchase Price shall be paid without interest within the term of the Repurchase Option as described in Section 7.2. 

7.5. Right of Termination Unaffected. Nothing in this Agreement shall be construed to limit or otherwise
affect in any manner whatsoever the right or power of the Company (or any Parent or Subsidiary of the Company) to terminate Optionee’s employment or other relationship with Company (or any Parent or Subsidiary of the Company) at any time, for
any reason or no reason, with or without Cause. 
 8. RESTRICTIONS ON TRANSFER. 

8.1. Disposition of Shares. Optionee hereby agrees that Optionee shall make no disposition of any of the Shares
(other than as permitted by this Agreement) unless and until: 
 (a) Optionee shall have notified the Company of the proposed disposition
and provided a written summary of the terms and conditions of the proposed disposition; 
 (b) Optionee shall have complied with all
requirements of this Agreement applicable to the disposition of the Shares; 
 (c) Optionee shall have provided the Company with written
assurances, in form and substance satisfactory to counsel for the Company, that (i) the proposed disposition does not require registration of the Shares under the Securities Act or under any applicable state securities laws or (ii) all
appropriate actions necessary for compliance with the registration requirements of the Securities Act or of any exemption from registration available under the Securities Act (including Rule 144) or applicable state securities laws have been taken;
and 
 (d) Optionee shall have provided the Company with written assurances, in form and substance satisfactory to the Company, that the
proposed disposition will not result in the contravention of any transfer restrictions applicable to the Shares pursuant to the provisions of the regulations promulgated under Rule 701 or under any other applicable securities laws or adversely
affect the Company’s ability to rely on the exemption(s) from registration under the Securities Act or under any other applicable securities laws for the grant of the Option, the issuance of Shares thereunder or any other issuance of securities
under the Plan. 

  
 4 

 8.2. Restriction on Transfer. Optionee shall not transfer,
assign, grant a lien or security interest in, pledge, hypothecate, encumber or otherwise dispose of any of the Shares which are subject to the Company’s Repurchase Option or the Right of First Refusal described below, except as permitted by
this Agreement. 
 8.3. Transferee Obligations. Each person (other than the Company) to whom the Shares are
transferred by means of one of the permitted transfers specified in this Agreement must, as a condition precedent to the validity of such transfer, acknowledge in writing to the Company that such person is bound by the provisions of this Agreement
and that the transferred Shares are subject to (i) both the Company’s Repurchase Option and the Company’s Right of First Refusal granted hereunder and (ii) the market stand-off provisions
of Section 9 below, to the same extent such Shares would be so subject if retained by Optionee. 
 9. MARKET STANDOFF
AGREEMENT. Optionee agrees that, subject to any early release provisions that apply pro rata to stockholders of the Company according to their holdings of Common Stock (determined on an as-converted into
Common Stock basis), Optionee will not, for a period of up to one hundred eighty (180) days (plus up to an additional thirty five (35) days to the extent reasonably requested by the Company or such underwriter(s) to accommodate regulatory
restrictions on the publication or other distribution of research reports or earnings releases by the Company, including NASD and NYSE rules) following the effective date of the registration statement filed with the SEC relating to the initial
underwritten sale of Common Stock of the Company to the public under the Securities Act (the “IPO”), directly or indirectly sell, offer to sell, grant any option for the sale of, or otherwise dispose of any Common Stock or
securities convertible into Common Stock, except for: (i) transfers of Shares permitted under Section 10.6 hereof so long as such transferee furnishes to the Company and the managing underwriter their written consent to be
bound by this Section 9 as a condition precedent to such transfer; and (ii) sales of any securities to be included in the registration statement for the IPO. For the avoidance of doubt, the provisions of this Section shall only apply to
the IPO. The restricted period shall in any event terminate two (2) years after the closing date of the IPO. In order to enforce the foregoing covenant, the Company shall have the right to place restrictive legends on the certificates
representing the Shares subject to this Section and to impose stop transfer instructions with respect to the Shares until the end of such period. Optionee further agrees to enter into any agreement reasonably required by the underwriters to
implement the foregoing restrictions on transfer. For the avoidance of doubt, the foregoing provisions of this Section shall not apply to any registration of securities of the Company (a) under an employee benefit plan or (b) in a merger,
consolidation, business combination or similar transaction. 
 10. COMPANY’S RIGHT OF FIRST REFUSAL. Unvested Shares may
not be sold or otherwise transferred, or pledged by Optionee or made subject to a security interest, pledge or other lien without the Company’s prior written consent, which may be withheld in the Company’s sole and absolute discretion.
Before any Vested Shares held by Optionee or any transferee of such Vested Shares (either sometimes referred to herein as the “Holder”) may be sold or otherwise transferred (including, without limitation, a transfer by gift
or operation of law), the Company and/or its assignee(s) will have a right of first refusal to purchase the Vested Shares to be sold or transferred (the “Offered Shares”) on the terms and conditions set forth in this Section
(the “Right of First Refusal”). 
 10.1. Notice of Proposed Transfer. The Holder of the
Offered Shares will deliver to the Company a written notice (the “Notice”) stating: (i) the Holder’s bona fide intention to sell or otherwise transfer the Offered Shares; (ii) the name and address of each
proposed purchaser or other transferee (the “Proposed Transferee”); (iii) the number of Offered Shares to be transferred to each Proposed Transferee; (iv) the bona fide cash price or other consideration for which the
Holder proposes to transfer the Offered Shares (the “Offered Price”); and (v) that the Holder acknowledges this Notice is an offer to sell the Offered Shares to the Company and/or its assignee(s) pursuant to the
Company’s Right of First Refusal at the Offered Price as provided for in this Agreement. 

  
 5 

 10.2. Exercise of Right of First Refusal. At any time within
thirty (30) days after the date of the Notice, the Company and/or its assignee(s) may, by giving written notice to the Holder, elect to purchase all (or, with the consent of the Holder, less than all) the Offered Shares proposed to be
transferred to any one or more of the Proposed Transferees named in the Notice, at the purchase price, determined as specified below. 

10.3. Purchase Price. The purchase price for the Offered Shares purchased under this Section will be the Offered
Price, provided that if the Offered Price consists of no legal consideration (as, for example, in the case of a transfer by gift) then the purchase price will be the fair market value of the Offered Shares as determined in good faith
by the Committee. If the Offered Price includes consideration other than cash, then the value of the non-cash consideration, as determined in good faith by the Committee, will conclusively be deemed to be the
cash equivalent value of such non-cash consideration. 
 10.4. Payment.
Payment of the purchase price for the Offered Shares will be payable, at the option of the Company and/or its assignee(s) (as applicable), by check or by cancellation of all or a portion of any outstanding purchase money indebtedness owed by the
Holder to the Company (or to such assignee, in the case of a purchase of Offered Shares by such assignee) or by any combination thereof. The purchase price will be paid without interest within sixty (60) days after the Company’s receipt of
the Notice, or, at the option of the Company and/or its assignee(s), in the manner and at the time(s) set forth in the Notice. 

10.5. Holder’s Right to Transfer. If all of the Offered Shares proposed in the Notice to be transferred to a
given Proposed Transferee are not purchased by the Company and/or its assignee(s) as provided in this Section, then the Holder may sell or otherwise transfer such Offered Shares to each Proposed Transferee at the Offered Price or at a higher price,
provided that (i) such sale or other transfer is consummated within ninety (90) days after the date of the Notice, (ii) any such sale or other transfer is effected in compliance with all applicable securities laws, and
(iii) each Proposed Transferee agrees in writing that the provisions of this Section will continue to apply to the Offered Shares in the hands of such Proposed Transferee. If the Offered Shares described in the Notice are not transferred to
each Proposed Transferee within such ninety (90) day period, then a new Notice must be given to the Company pursuant to which the Company will again be offered the Right of First Refusal before any Shares held by the Holder may be sold or
otherwise transferred. 
 10.6. Exempt Transfers. Notwithstanding anything to the contrary in this Section, the
following transfers of Vested Shares will be exempt from the Right of First Refusal: (i) the transfer of any or all of the Vested Shares during Optionee’s lifetime by gift or on Optionee’s death by will or intestacy to any member(s)
of Optionee’s “Immediate Family” (as defined below) or to a trust for the benefit of Optionee and/or member(s) of Optionee’s Immediate Family, provided that each transferee or other recipient agrees in a writing
satisfactory to the Company that the provisions of this Section will continue to apply to the transferred Vested Shares in the hands of such transferee or other recipient; (ii) any transfer of Vested Shares made pursuant to a statutory merger,
statutory consolidation of the Company with or into another corporation or corporations or a conversion of the Company into another form of legal entity (except that the Right of First Refusal will continue to apply thereafter to such Vested Shares,
in which case the surviving corporation of such merger or consolidation or the resulting entity of such conversion shall succeed to the rights of the Company under this Section unless the agreement of merger or consolidation or conversion expressly
otherwise provides); or (iii) any transfer of Vested Shares pursuant to the winding up and dissolution of the Company. As used herein, the term “Immediate Family” will mean Optionee’s spouse, the lineal descendant
or antecedent, father, mother, brother or sister, child, adopted child, grandchild or adopted grandchild of Optionee or Optionee’s spouse, or the spouse of any of the above or Spousal Equivalent, as defined herein. As used herein, a person is
deemed to be a “Spousal Equivalent” provided the following circumstances are true: (i) irrespective of whether or not Optionee and the Spousal Equivalent are the same sex, they are the sole spousal equivalent of the
other for the last twelve (12) months, (ii) they intend to remain so indefinitely, (iii) neither are married to anyone else, (iv) both are at least 18 years of age and mentally competent to consent to contract, (v) they are not
related by blood to a degree of closeness that which would prohibit legal marriage in the state in which they legally reside, (vi) they are jointly responsible for each other’s common welfare and financial obligations, and (vii) they
reside together in the same residence for the last twelve (12) months and intend to do so indefinitely. 

  
 6 

 10.7. Termination of Right of First Refusal. The Right of First
Refusal will terminate as to all Shares: (i) on the effective date of the first sale of Common Stock of the Company to the general public pursuant to a registration statement filed with and declared effective by the SEC under the
Securities Act (other than a registration statement relating solely to the issuance of Common Stock pursuant to a business combination or an employee incentive or benefit plan); (ii) on any transfer or conversion of Shares made pursuant to a
statutory merger or statutory consolidation of the Company with or into another corporation or corporations if the common stock of the surviving corporation or any direct or indirect parent corporation thereof is registered under the Exchange
Act; or (iii) on any transfer or conversion of Shares made pursuant to a statutory conversion of the Company into another form of legal entity if the common equity (or comparable equity security) of entity resulting from such conversion
is registered under the Exchange Act. 
 10.8. Encumbrances on Vested Shares. Optionee may grant a lien or
security interest in, or pledge, hypothecate or encumber Vested Shares only if each party to whom such lien or security interest is granted, or to whom such pledge, hypothecation or other encumbrance is made, agrees in a writing satisfactory to the
Company that: (i) such lien, security interest, pledge, hypothecation or encumbrance will not adversely affect or impair the Right of First Refusal or the rights of the Company and/or its assignee(s) with respect thereto and will not apply to
such Vested Shares after they are acquired by the Company and/or its assignees under this Section; and (ii) the provisions of this Agreement will continue to apply to such Vested Shares in the hands of such party and any transferee of such
party. Optionee may not grant a lien or security interest in, or pledge, hypothecate or encumber, any Unvested Shares. 
 11.
RIGHTS AS A STOCKHOLDER. Optionee shall not have any of the rights of a stockholder with respect to any Shares unless and until such Shares are issued to Optionee. Subject to the terms and conditions of this Agreement, Optionee will have all
of the rights of a stockholder of the Company with respect to the Shares from and after the date that Shares are issued to Optionee pursuant to, and in accordance with, the terms of the Exercise Agreement until such time as Optionee disposes of the
Shares or the Company and/or its assignee(s) exercise(s) the Repurchase Option or the Right of First Refusal. Upon an exercise of the Repurchase Option or the Right of First Refusal, Optionee will have no further rights as a holder of the Shares so
purchased upon such exercise, other than the right to receive payment for the Shares so purchased in accordance with the provisions of this Agreement, and Optionee will promptly surrender the stock certificate(s) evidencing the Shares so purchased
to the Company for transfer or cancellation. 
 12. ESCROW. As security for Optionee’s faithful performance of this
Agreement, Optionee agrees, immediately upon receipt of the stock certificate(s) evidencing the Shares, to deliver such certificate(s) to the Secretary of the Company or other designee of the Company (the “Escrow Holder”),
who is hereby appointed to hold such certificate(s) and to take all such actions and to effectuate all such transfers and/or releases of such Shares as are in accordance with the terms of this Agreement. Optionee and the Company agree that Escrow
Holder will not be liable to any party to this Agreement (or to any other party) for any actions or omissions unless Escrow Holder is grossly negligent or intentionally fraudulent in carrying out the duties of Escrow Holder under this Agreement.
Escrow Holder may rely upon any letter, notice or other document executed with any signature purported to be genuine and may rely on the advice of counsel and obey any order of any court with respect to the transactions contemplated by this
Agreement and will not be liable for any act or omission taken by Escrow Holder in good faith reliance on such documents, the advice of counsel or a court order. The Shares will be released from escrow upon termination of both the Repurchase Option
and the Right of First Refusal. 

  
 7 

 13. RESTRICTIVE LEGENDS AND STOP-TRANSFER ORDERS. 

13.1. Legends. Optionee understands and agrees that the Company will place the legends set forth below or similar
legends on any stock certificate(s) evidencing the Shares, together with any other legends that may be required by state or U.S. Federal securities laws, the Company’s Certificate of Incorporation or Bylaws, any other agreement between Optionee
and the Company, or any agreement between Optionee and any third party (and any other legend(s) that the Company may become obligated to place on the stock certificate(s) evidencing the Shares under the terms of any agreement to which the Company is
or may become bound or obligated): 
 (a) THE SECURITIES REPRESENTED HEREBY HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS
AMENDED (THE “SECURITIES ACT”), OR UNDER THE SECURITIES LAWS OF CERTAIN STATES. THESE SECURITIES ARE SUBJECT TO RESTRICTIONS ON TRANSFERABILITY AND RESALE AND MAY NOT BE TRANSFERRED OR RESOLD EXCEPT AS PERMITTED UNDER THE SECURITIES ACT
AND APPLICABLE STATE SECURITIES LAWS, PURSUANT TO REGISTRATION OR EXEMPTION THEREFROM. INVESTORS SHOULD BE AWARE THAT THEY MAY BE REQUIRED TO BEAR THE FINANCIAL RISKS OF THIS INVESTMENT FOR AN INDEFINITE PERIOD OF TIME. THE ISSUER OF THESE
SECURITIES MAY REQUIRE AN OPINION OF COUNSEL IN FORM AND SUBSTANCE SATISFACTORY TO THE ISSUER TO THE EFFECT THAT ANY PROPOSED TRANSFER OR RESALE IS IN COMPLIANCE WITH THE SECURITIES ACT AND ANY APPLICABLE STATE SECURITIES LAWS. 

(b) THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO CERTAIN RESTRICTIONS ON RESALE AND TRANSFER, INCLUDING THE REPURCHASE OPTION
AND RIGHT OF FIRST REFUSAL HELD BY THE ISSUER AND/OR ITS ASSIGNEE(S) AS SET FORTH IN A STOCK OPTION AGREEMENT BETWEEN THE ISSUER AND THE ORIGINAL HOLDER OF THESE SHARES, A COPY OF WHICH MAY BE OBTAINED AT THE PRINCIPAL OFFICE OF THE ISSUER. SUCH
SALE AND TRANSFER RESTRICTIONS, INCLUDING THE REPURCHASE OPTION AND RIGHT OF FIRST REFUSAL, ARE BINDING ON TRANSFEREES OF THESE SHARES. 

(c) THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO A MARKET STANDOFF RESTRICTION AS SET FORTH IN A CERTAIN STOCK OPTION AGREEMENT
BETWEEN THE ISSUER AND THE ORIGINAL HOLDER OF THESE SHARES, A COPY OF WHICH MAY BE OBTAINED AT THE PRINCIPAL OFFICE OF THE ISSUER. AS A RESULT OF SUCH AGREEMENT, THESE SHARES MAY NOT BE TRADED PRIOR TO 180 DAYS AFTER THE EFFECTIVE DATE OF CERTAIN
PUBLIC OFFERINGS OF THE COMMON STOCK OF THE ISSUER HEREOF. SUCH RESTRICTION IS BINDING ON TRANSFEREES OF THESE SHARES. 
 13.2.
Stop-Transfer Instructions. Optionee agrees that, to ensure compliance with the restrictions imposed by this Agreement, the Company may issue appropriate “stop-transfer” instructions to its transfer agent, if any, and
if the Company transfers its own securities, it may make appropriate notations to the same effect in its own records. 
 13.3.
Refusal to Transfer. The Company will not be required (i) to transfer on its books any Shares that have been sold or otherwise transferred in violation of any of the provisions of this Agreement or (ii) to treat as
owner of such Shares, or to accord the right to vote or pay dividends to any purchaser or other transferee to whom such Shares have been so transferred. 

14. CERTAIN TAX CONSEQUENCES. Set forth below is a brief summary as of the Effective Date of the Plan of some of the federal tax
consequences of exercise of the Option and disposition of the Shares. THIS SUMMARY IS NECESSARILY INCOMPLETE, AND THE TAX LAWS AND REGULATIONS ARE SUBJECT TO CHANGE. OPTIONEE SHOULD CONSULT A TAX ADVISER BEFORE EXERCISING THE OPTION OR DISPOSING OF
THE SHARES. 
 14.1. Exercise of ISO. If the Option qualifies as an ISO, there will be no regular federal income
tax liability upon the exercise of the Option, although the excess, if any, of the Fair Market Value of the Shares on the date of exercise over the Exercise Price will be treated as a tax preference item for federal alternative minimum tax purposes
and may subject Optionee to the alternative minimum tax in the year of exercise. 

  
 8 

 14.2. Exercise of Nonqualified Stock Option. If the Option does
not qualify as an ISO, there may be a regular federal income tax liability upon the exercise of the Option. Optionee will be treated as having received compensation income (taxable at ordinary income tax rates) equal to the excess, if any, of the
Fair Market Value of the Shares on the date of exercise over the Exercise Price. If Optionee is a current or former employee of the Company, the Company may be required to withhold from Optionee’s compensation or collect from Optionee and pay
to the applicable taxing authorities an amount equal to a percentage of this compensation income at the time of exercise. 
 14.3.
Disposition of Shares. The following tax consequences may apply upon disposition of the Shares. 
 (a) Incentive
Stock Options. If the Shares are held for more than twelve (12) months after the date of purchase of the Shares pursuant to the exercise of an ISO and are disposed of more than two (2) years after the Date of Grant, any gain realized
on disposition of the Shares will be treated as long term capital gain for federal income tax purposes. If Vested Shares purchased under an ISO are disposed of within the applicable one (1) year or two (2) year period, any gain realized on
such disposition will be treated as compensation income (taxable at ordinary income rates in the year of the disposition) to the extent of the excess, if any, of the Fair Market Value of the Shares on the date of exercise over the Exercise Price. To
the extent the Shares were exercised prior to vesting coincident with the filing of an 83(b) Election, the amount taxed because of a disqualifying disposition will be based upon the excess, if any, of the fair market value on the date of
vesting over the exercise price. 
 (b) Nonqualified Stock Options. If the Shares are held for more than twelve
(12) months after the date of purchase of the Shares pursuant to the exercise of an NQSO, any gain realized on disposition of the Shares will be treated as long term capital gain. 

14.4. Section 83(b) Election for Unvested Shares. With respect to Unvested Shares, which are subject to the
Repurchase Option, unless an election is filed by Optionee with the Internal Revenue Service (and, if necessary, the proper state taxing authorities), within thirty (30) days of the purchase of the Unvested Shares, electing
pursuant to Section 83(b) of the Code (and similar state tax provisions, if applicable) to be taxed currently on any difference between the Exercise Price of the Unvested Shares and their Fair Market Value on the date of purchase, there may be
a recognition of taxable income (including, where applicable, alternative minimum taxable income) to Optionee, measured by the excess, if any, of the Fair Market Value of the Unvested Shares at the time they cease to be Unvested Shares, over the
Exercise Price of the Unvested Shares. 
 15. GENERAL PROVISIONS. 

15.1. Interpretation. Any dispute regarding the interpretation of this Agreement shall be submitted by Optionee or
the Company to the Committee for review. The resolution of such a dispute by the Committee shall be final and binding on the Company and Optionee. 

15.2. Entire Agreement. The Plan, the Grant Notice and the Exercise Agreement are each incorporated herein by
reference. This Agreement, the Grant Notice, the Plan and the Exercise Agreement constitute the entire agreement of the parties with respect to the subject matter hereof and supersede all prior undertakings and agreements with respect to such
subject matter. 
 16. NOTICES. Any and all notices required or permitted to be given to a party pursuant to the provisions of
this Agreement will be in writing and will be effective and deemed to provide such party sufficient notice under this Agreement on the earliest of the following: (i) at the time of personal delivery, if delivery is in person; (ii) at the
time an electronic confirmation of receipt is received, if delivery is by email; (iii) at the time of transmission by facsimile, addressed to the other party at its facsimile number specified herein (or hereafter modified by subsequent notice
to the parties hereto), with confirmation of 

  
 9 

 
receipt made by both telephone and printed confirmation sheet verifying successful transmission of the facsimile; (iv) one (1) business day after deposit with an express overnight courier
for United States deliveries, or two (2) business days after such deposit for deliveries outside of the United States, with proof of delivery from the courier requested; or (v) three (3) business days after deposit in the United States
mail by certified mail (return receipt requested) for United States deliveries. Any notice for delivery outside the United States will be sent by email, facsimile or by express courier. Any notice not delivered personally or by email will be sent
with postage and/or other charges prepaid and properly addressed to Optionee at the last known address or facsimile number on the books of the Company, or at such other address or facsimile number as such other party may designate by one of the
indicated means of notice herein to the other parties hereto or, in the case of the Company, to it at its principal place of business. Notices to the Company will be marked “Attention: Chief Financial Officer.” Notices by facsimile shall
be machine verified as received. 
 17. SUCCESSORS AND ASSIGNS. The Company may assign any of its rights under this Agreement
including its rights to purchase Shares under both the Right of First Refusal and Repurchase Option. This Agreement shall be binding upon and inure to the benefit of the successors and assigns of the Company. Subject to the restrictions on transfer
set forth herein, this Agreement shall be binding upon Optionee and Optionee’s heirs, executors, administrators, legal representatives, successors and assigns. 

18. GOVERNING LAW. This Agreement shall be governed by and construed in accordance with the internal laws of the State of
Delaware as such laws are applied to agreements between Delaware residents entered into and to be performed entirely within Delaware. If any provision of this Agreement is determined by a court of law to be illegal or unenforceable, then such
provision will be enforced to the maximum extent possible and the other provisions will remain fully effective and enforceable. 

19. FURTHER ASSURANCES. The parties agree to execute such further documents and instruments and to take such further
actions as may be reasonably necessary to carry out the purposes and intent of this Agreement. 
 20. TITLES AND HEADINGS.
The titles, captions and headings of this Agreement are included for ease of reference only and will be disregarded in interpreting or construing this Agreement. Unless otherwise specifically stated, all references herein to “sections”
and “exhibits” will mean “sections” and “exhibits” to this Agreement. 
 21. COUNTERPARTS.
This Agreement may be executed in any number of counterparts, each of which when so executed and delivered will be deemed an original, and all of which together shall constitute one and the same agreement. 

22. SEVERABILITY. If any provision of this Agreement is determined by any court or arbitrator of competent jurisdiction
to be invalid, illegal or unenforceable in any respect, such provision will be enforced to the maximum extent possible given the intent of the parties hereto. If such clause or provision cannot be so enforced, such provision shall be stricken from
this Agreement and the remainder of this Agreement shall be enforced as if such invalid, illegal or unenforceable clause or provision had (to the extent not enforceable) never been contained in this Agreement. Notwithstanding the forgoing, if the
value of this Agreement based upon the substantial benefit of the bargain for any party is materially impaired, which determination as made by the presiding court or arbitrator of competent jurisdiction shall be binding, then both parties agree to
substitute such provision(s) through good faith negotiations. 
 * * * * * 

Attachments: Annex A: Form of Stock Option Exercise Notice and Agreement 

  
 10 

 ANNEX A 

FORM OF STOCK OPTION EXERCISE NOTICE AND AGREEMENT 

 EARLY EXERCISE FORM 

STOCK OPTION EXERCISE NOTICE AND AGREEMENT 

PRELUDE THERAPEUTICS INCORPORATED 

2016 STOCK INCENTIVE PLAN 

*NOTE: You must sign this Notice on
Page 3 before submitting it to Prelude Therapeutics Incorporated (the “Company”).  

OPTIONEE INFORMATION: Please provide the following information about yourself
(“Optionee”): 
  

									
	Name:	 	  
	 		  	Social Security Number:	 	
                     

					
	Address:	 	
                 
	 	        	  	Employee Number:	 	              

					
		 	              
	 		  	Email Address:	 	  

 OPTION INFORMATION: Please provide this information on the option being exercised
(the “Option”): 
  

			
	Grant No.	  	
		
	Date of Grant:	  	Type of Stock Option:
		
	Option Price per Share: $____	  	☐ Nonqualified (NQSO)
		
	Total number of shares of Common Stock of the Company subject to the Option:	  	☐ Incentive (ISO)

 EXERCISE INFORMATION: 

Number of shares of Common Stock of the Company for which the Option is now being exercised [________________]. (These shares are referred to below as the
“Purchased Shares.”) 
 Total Exercise Price Being Paid for the Purchased Shares: $____________ 

Form of payment enclosed [check all that apply]: 
  

	☐	 Check for $____________, payable to “Prelude Therapeutics Incorporated.”

  

	☐	 Certificate(s) for ________________ shares of Common Stock of the Company. These shares will be valued as of
the date this notice is received by the Company. [Requires Company consent.] 

  

	☐	 Automated Clearing House (“ACH”) transfer in the amount of $___________.

 AGREEMENTS, REPRESENTATIONS AND ACKNOWLEDGMENTS OF
OPTIONEE:    By signing this Stock Option Exercise Notice and Agreement, Optionee hereby agrees with, and represents to, the Company as follows: 

 

	1.	 Terms Governing. I acknowledge and agree with the Company that I am acquiring the Purchased Shares by
exercise of this Option subject to all other terms and conditions of the Notice of Stock Option Grant and the Stock Option Agreement that govern the Option, including without limitation the terms of the Company’s 2016 Stock Incentive Plan, as
it may be amended (the “Plan”). 

  

	2.	 Investment Intent; Securities Law Restrictions. I represent and warrant to the Company that I am
acquiring and will hold the Purchased Shares for investment for my account only, and not with a view to, or for resale in connection with, any “distribution” of the Purchased Shares within the meaning of the Securities Act of 1933, as
amended (the “Securities Act”). I understand that the Purchased Shares 

 EARLY EXERCISE FORM 

 

 have not been registered under the Securities Act by reason of a specific exemption from such
registration requirement and that the Purchased Shares must be held by me indefinitely, unless they are subsequently registered under the Securities Act or I obtain an opinion of counsel (in form and substance satisfactory to the Company and its
counsel) that registration is not required. I acknowledge that the Company is under no obligation to register the Purchased Shares under the Securities Act or under any other securities law. 

 

	3.	 Restrictions on Transfer: Rule 144. I will not sell, transfer or otherwise dispose of the Purchased
Shares in violation of the Securities Act, the Securities Exchange Act of 1934, or the rules promulgated thereunder (including Rule 144 under the Securities Act described below (“Rule 144”)) or of any other applicable
securities laws. I am aware of Rule 144, which permits limited public resales of securities acquired in a non-public offering, subject to satisfaction of certain conditions, which include (without
limitation) that: (a) certain current public information about the Company is available; (b) the resale occurs only after the holding period required by Rule 144 has been met; (c) the sale occurs through an unsolicited
“broker’s transaction;” and (d) the amount of securities being sold during any three-month period does not exceed specified limitations. I understand that the conditions for resale set forth in Rule 144 have not been
satisfied and that the Company has no plans to satisfy these conditions in the foreseeable future. 

  

	4.	 Access to Information; Understanding of Risk in Investment. I acknowledge that I have received and had
access to such information as I consider necessary or appropriate for deciding whether to invest in the Purchased Shares and that I had an opportunity to ask questions and receive answers from the Company regarding the terms and conditions of the
issuance of the Purchased Shares. I am aware that my investment in the Company is a speculative investment that has limited liquidity and is subject to the risk of complete loss. I am able, without impairing my financial condition, to hold the
Purchased Shares for an indefinite period and to suffer a complete loss of my investment in the Purchased Shares. 

  

	5.	 Rights of First Refusal; Repurchase Options; Market Stand-off. I
acknowledge that the Purchased Shares remain subject to the Company’s Right of First Refusal, the Company’s Repurchase Option (with respect to unvested Purchased Shares) and the market stand-off
covenants (sometimes referred to as the “lock-up”), all in accordance with the applicable Notice of Stock Option Grant and the Stock Option Agreement that govern the Option 

 

	6.	 Form of Ownership.    I acknowledge that the Company has encouraged me to consult my
own adviser to determine the form of ownership of the Purchased Shares that is appropriate for me. In the event that I choose to transfer my Purchased Shares to a trust, I agree to sign a Stock Transfer Agreement. In the event that I choose to
transfer my Purchased Shares to a trust that is not an eligible revocable trust, I also acknowledge that the transfer will be treated as a “disposition” for tax purposes. As a result, the favorable ISO tax treatment will be unavailable and
other unfavorable tax consequences may occur. 

  

	7.	 Investigation of Tax Consequences. I acknowledge that the Company has encouraged me to consult my own
adviser to determine the tax consequences of acquiring the Purchased Shares at this time. 

  

	8.	 Other Tax Matters. I agree that the Company does not have a duty to design or administer the Plan or its
other compensation programs in a manner that minimizes my tax liabilities. I will not make any claim against the Company or its Board, officers or employees related to tax liabilities arising from my options or my other compensation. In particular,
I acknowledge that my options (including the Option) are exempt from Section 409A of the Internal Revenue Code only if the exercise price per share is at least equal to the fair market value per share of the Common Stock at the time the option
was granted by the Board. Since shares of the Common Stock are not traded on an established securities market, the determination of their fair market value was made by the Board and/or by an independent valuation firm retained by the Company. I
acknowledge that there is no guarantee in either case that the Internal Revenue Service will agree with the valuation, and I will not make any claim against the Company or its Board of Directors, officers or employees in the event that the Internal
Revenue Service asserts that the valuation was too low. 

  
 2 

 EARLY EXERCISE FORM 

 

	9.	 Spouse Consent. I agree to seek the consent of my spouse to the extent required by the Company to
enforce the foregoing. 

  

	10.	 Tax Withholding. As a condition of exercising this Option, I agree to make adequate provision for
foreign, federal, state or other tax withholding obligations, if any, which arise upon the grant, vesting or exercise of this Option, or disposition of the Purchased Shares, whether by withholding, direct payment to the Company, or otherwise.

 IMPORTANT NOTE: UNVESTED PURCHASED SHARES ARE SUBJECT TO REPURCHASE BY THE COMPANY. PLEASE CONSULT WITH YOUR TAX
ADVISER CONCERNING THE ADVISABILITY OF FILING AN 83(b) ELECTION WITH THE INTERNAL REVENUE SERVICE WHICH MUST BE FILED WITHIN THIRTY (30) DAYS AFTER THE PURCHASE OF SHARES TO BE EFFECTIVE.  

A form of Election under Section 83(b) is attached hereto as Exhibit 1 for reference. Unless an 83(b) election is timely filed with the
Internal Revenue Service (and, if necessary, the proper state taxing authorities), electing pursuant to Section 83(b) of the Internal Revenue Code (and similar state tax provisions, if applicable) to be taxed currently on any difference between
the purchase price of the Unvested Purchased Shares and their fair market value on the date of purchase, there may be a recognition of taxable income (including, where applicable, alternative minimum taxable income) to you, measured by the excess,
if any, of the Fair Market Value of the Unvested Purchased Shares at the time they cease to be Unvested Purchased Shares, over the purchase price of the Unvested Purchased Shares. 

The undersigned hereby executes and delivers this Stock Option Exercise Notice and Agreement and agrees to be bound by its terms 

 

					
	SIGNATURE:	  		  	DATE:
	
                     
                
	  		  	  

	Optionee’s Name:	  		  	
			
	Attachments: 	  	        	  	
			
	Exhibit 1 – Section 83(b) Election Form	  		  	

 [Signature Page to Stock Option Exercise Notice and Agreement] 

  
 3 

 EARLY EXERCISE FORM 

 

 EXHIBIT 1 

SECTION 83(b) ELECTION 

 ELECTION UNDER SECTION 83(b) OF THE 

INTERNAL REVENUE CODE 
 The undersigned
Taxpayer hereby elects, pursuant to Section 83(b) of the Internal Revenue Code of 1986, as amended, to include the excess, if any, of the fair market value of the property described below at the time of transfer over the amount paid for such
property, as compensation for services in the calculation of: (1) regular gross income; (2) alternative minimum taxable income; or (3) disqualifying disposition gross income, as the case may be. 

 

					
	1.    	  	TAXPAYER’S NAME:	  	
                     
                            

			
		  	TAXPAYER’S ADDRESS:     	  	  

			
		  		  	  

			
		  	SOCIAL SECURITY NUMBER:      	  	  

  

	2.	 The property with respect to which the election is made is described as follows: _______ shares of Common
Stock, par value $0.0001 per share, of Prelude Therapeutics Incorporated, a Delaware corporation (the “Company”), which were transferred upon exercise of an option by the Company, which is Taxpayer’s employer or the
corporation for whom the Taxpayer performs services. 

  

	3.	 The date on which the shares were transferred was pursuant to the exercise of the option was
____________________, _____ and this election is made for calendar year ____. 

  

	4.	 The shares received upon exercise of the option are subject to the following restrictions: The Company may
repurchase all or a portion of the shares at Taxpayer’s original purchase price per share, under certain conditions at the time of Taxpayer’s termination of employment or services. 

 

	5.	 The fair market value of the shares (without regard to restrictions other than restrictions which by their
terms will never lapse) was $_____ per share x _______ shares = $_______ at the time of exercise of the option. 

  

	6.	 The amount paid for such shares upon exercise of the option was $____ per share x ________ shares = $________.

  

	7.	 The Taxpayer has submitted a copy of this statement to the Company. 

 

	8.	 The amount to include in gross income is $______________. [The result of the amount reported in Item 5 minus
the amount reported in Item 6.] 

 THIS ELECTION MUST BE FILED WITH THE INTERNAL REVENUE SERVICE
(“IRS”), AT THE OFFICE WHERE THE TAXPAYER FILES ANNUAL INCOME TAX RETURNS, WITHIN 30 DAYS AFTER THE DATE OF TRANSFER OF THE SHARES, AND MUST ALSO BE FILED WITH THE TAXPAYER’S INCOME TAX RETURNS FOR THE
CALENDAR YEAR. THE ELECTION CANNOT BE REVOKED WITHOUT THE CONSENT OF THE IRS. 
  

							
	Dated:	 	  
	 	      	 	  

		 		 		 	Taxpayer’s Signature

 OPTION GRANT NO. ___ 

NOTICE OF STOCK OPTION GRANT 

PRELUDE THERAPEUTICS INCORPORATED 

2016 STOCK INCENTIVE PLAN 

The Optionee named below (“Optionee”) has been granted an option (this “Option”) to purchase shares of Common
Stock, $0.0001 par value per share (the “Common Stock”), of Prelude Therapeutics Incorporated, a Delaware corporation (the “Company”), pursuant to the Company’s 2016 Stock Incentive Plan,
as amended from time to time (the “Plan”) on the terms, and subject to the conditions, described below and in the Stock Option Agreement attached hereto as Exhibit A, including
its annexes (the “Stock Option Agreement”). 
  

			
	Optionee:	  	
		
	Maximum Number of Shares Subject to this Option (the “Shares”):	  	
		
	Exercise Price Per Share:	  	$____ per share
		
	Date of Grant:	  	
		
	Vesting Start Date:	  	
		
	Exercise Schedule:	  	This Option will become exercisable during its term with respect to portions of the Shares in accordance with the Vesting Schedule set forth below.
		
	Expiration Date:	  	The date ten (10) years after the Date of Grant set forth above, subject to earlier expiration in the event of Termination as provided in Section 3 of the Stock Option Agreement.
		
	 Tax Status of Option:
 (Check Only
One Box):
	  	 ☐ Incentive Stock Option (To the fullest extent permitted by the Code)

☐ Nonqualified Stock Option.
 (If
neither box is checked, this Option is a Nonqualified Stock Option).

 Vesting Schedule [EXAMPLE ONLY]: For so long as Optionee continuously provides services to the Company (or any
Subsidiary or Parent of the Company) as an employee, officer, director, contractor or consultant, this Option will vest (that is, become exercisable) with respect to the Shares as follows: (a) prior to the first one (1) year anniversary of
the Vesting Start Date this Option will not be vested or exercisable as to any of the Shares; (b) this Option will become vested and exercisable with respect to [1/4th]
of the Shares on the one (1) year anniversary of the Vesting Start Date; and (c) thereafter, this Option will become vested and exercisable with respect to an additional
[1/48th] of the Shares when Optionee completes each month of continuous service following the first one (1) year anniversary of the Vesting Start Date. 

General; Agreement: By their signatures below, Optionee and the Company agree that this Option is granted under and governed by this Notice of Stock
Option Grant (this “Grant Notice”) and by the provisions of the Plan and the Stock Option Agreement. The Plan and the Stock Option Agreement are incorporated herein by reference. Capitalized terms used but not defined herein
shall have the meanings given to them in the Plan or in the Stock Option Agreement, as applicable. By signing below, Optionee acknowledges receipt of a copy of this Grant Notice, the Plan and the Stock Option Agreement, represents that Optionee has
carefully read and is familiar with their provisions, and hereby accepts the Option subject to all of their respective terms and conditions. Optionee acknowledges that there may be adverse tax consequences upon exercise of the Option or disposition
of the Shares and that Optionee should consult a tax adviser prior to such exercise or disposition. Optionee agrees and acknowledges that the Vesting Schedule may change prospectively in the event that Optionee’s service status changes between
full and part time status in accordance with Company policies relating to work schedules and vesting of equity awards. 
 Execution and Delivery:
This Grant Notice may be executed and delivered electronically whether via the Company’s intranet or the Internet site of a third party or via email or any other means of electronic delivery specified by the Company. By Optionee’s
acceptance hereof (whether written, electronic or otherwise), Optionee agrees, to the fullest extent permitted by law, that in lieu of receiving documents in paper format, Optionee accepts the electronic delivery of any documents that the Company
(or any third party the Company may designate), may deliver in connection with this grant (including the Plan, this Grant Notice, the Stock Option Agreement, the information described in Rules 701(e)(2), (3), (4) and (5) under the Securities
Act (the “701 Disclosures”), account statements, or other communications or information) whether via the Company’s intranet or the Internet site of such third party or via email or such other means of electronic delivery
specified by the Company. 
  

									
	PRELUDE THERAPEUTICS INCORPORATED 	  	
					
	By /Signature:	  	  
	  		  	Optionee Signature:	  	  

					
	Typed Name:	  	  
	  	      	  	Optionee’s Name:	  	  

					
	Title:	  	  
	  		  		  	
				
	ATTACHMENT: Exhibit A – Stock Option Agreement	  		  		  	

 Exhibit A 

Stock Option Agreement 

 EXHIBIT A 

STOCK OPTION AGREEMENT 

PRELUDE THERAPEUTICS INCORPORATED 

2016 STOCK INCENTIVE PLAN 

This Stock Option Agreement (this “Agreement”) is made and entered into as of the date of grant (the “Date
of Grant”) set forth on the Notice of Stock Option Grant attached as the facing page to this Agreement (the “Grant Notice”) by and between Prelude Therapeutics Incorporated, a Delaware corporation (the
“Company”), and the optionee named on the Grant Notice (“Optionee”). Capitalized terms not defined in this Agreement shall have the meaning ascribed to them in the Company’s 2016 Stock Incentive
Plan, as amended from time to time (the “Plan”), or in the Grant Notice, as applicable. 
 1. GRANT
OF OPTION. The Company hereby grants to Optionee an option (this “Option”) to purchase up to the total number of shares of Common Stock of the Company, $0.0001 par value per share (the “Common
Stock”), set forth in the Grant Notice as the Shares (the “Shares”) at the Exercise Price Per Share set forth in the Grant Notice (the “Exercise Price”), subject to all of the terms and
conditions of the Grant Notice, this Agreement and the Plan. If designated as an Incentive Stock Option in the Grant Notice, this Option is intended to qualify as an incentive stock option (the “ISO”) within the meaning of
Section 422 of the Internal Revenue Code of 1986, as amended (the “Code”), except that if on the Date of Grant Optionee is not subject to U.S. income tax, then this Option shall be a NQSO. 

2. EXERCISE PERIOD. 

2.1 Exercise Period of Option. This Option is considered to be “vested” with respect to any particular
Shares when this Option is exercisable with respect to such Shares. This Option will become vested during its term as to portions of the Shares in accordance with the Vesting Schedule set forth in the Grant Notice. Notwithstanding any provision in
the Plan or this Agreement to the contrary, on or after Optionee’s Termination Date, this Option may not be exercised with respect to any Shares that are Unvested Shares on Optionee’s Termination Date. 

2.2 Vesting of Option Shares. Shares with respect to which this Option is vested and exercisable at a given time
pursuant to the Vesting Schedule set forth in the Grant Notice are “Vested Shares.” Shares with respect to which this Option is not vested and exercisable at a given time pursuant to the Vesting Schedule set forth in
the Grant Notice are “Unvested Shares.” 
 2.3 Expiration. The Option
shall expire on the Expiration Date set forth in the Grant Notice or earlier as provided in Section 3 below. 
 3. TERMINATION.

 3.1 Termination for Any Reason Except Death, Disability or Cause. Except as provided in subsection 3.2 in
a case in which Optionee dies within three (3) months after Optionee is Terminated other than for Cause, if Optionee is Terminated for any reason (other than Optionee’s death or Disability or for Cause), then (a) on and after
Optionee’s Termination Date, this Option shall expire immediately with respect to any Shares that are Unvested Shares and may not be exercised with respect to any Shares that are Unvested Shares on Optionee’s Termination Date and
(b) this Option to the extent that it is exercisable with respect to Vested Shares on Optionee’s Termination Date, may be exercised by Optionee no later than three (3) months after Optionee’s Termination Date (but in no
event may this Option be exercised after the Expiration Date). 

 3.2 Termination Because of Death or Disability. If Optionee is
Terminated because of Optionee’s death or Disability (or if Optionee dies within three (3) months of the date of Optionee’s Termination for any reason other than for Cause), then (a) on and after Optionee’s Termination Date,
this Option shall expire immediately with respect to any Shares that are Unvested Shares and may not be exercised with respect to any Shares that are Unvested Shares on Optionee’s Termination Date and (b) this Option, to the extent that it
is exercisable with respect to Vested Shares on Optionee’s Termination Date, may be exercised by Optionee (or Optionee’s legal representative) no later than twelve (12) months after Optionee’s Termination Date, but in no event
later than the Expiration Date. Any exercise of this Option beyond (i) three (3) months after the date Optionee ceases to be an employee when Optionee’s Termination is for any reason other than Optionee’s death or disability,
within the meaning of Section 22(e)(3) of the Code; or (ii) twelve (12) months after the date Optionee ceases to be an employee when the termination is for Optionee’s disability, within the meaning of Section 22(e)(3) of the
Code, is deemed to be an NQSO. 
 3.3 Termination for Cause. If Optionee is Terminated for Cause, then
Optionee may exercise this Option, but only with respect to any Shares that are Vested Shares on Optionee’s Termination Date, and this Option shall expire on Optionee’s Termination Date, or at such later time and on such conditions as may
be affirmatively determined by the Committee. On and after Optionee’s Termination Date, this Option shall expire immediately with respect to any Shares that are Unvested Shares and may not be exercised with respect to any Shares that are
Unvested Shares on Optionee’s Termination Date. 
 3.4 No Obligation to Employ. Nothing in the Plan or this
Agreement shall confer on Optionee any right to continue in the employ of, or other relationship with, the Company or any Parent or Subsidiary of the Company, or limit in any way the right of the Company or any Parent or Subsidiary of the Company to
terminate Optionee’s employment or other relationship at any time, with or without Cause. 
 4. MANNER OF EXERCISE. 

4.1 Stock Option Exercise Notice and Agreement. To exercise this Option, Optionee (or in the case of exercise after
Optionee’s death or incapacity, Optionee’s executor, administrator, heir or legatee, as the case may be) must deliver to the Company an executed Stock Option Exercise Notice and Agreement in the form attached hereto as
Annex A, or in such other form as may be approved by the Committee from time to time (the “Exercise Agreement”) and payment for the shares being purchased in accordance with this
Agreement. The Exercise Agreement shall set forth, among other things, (i) Optionee’s election to exercise this Option, (ii) the number of Shares being purchased, (iii) any representations, warranties and agreements regarding
Optionee’s investment intent and access to information as may be required by the Company to comply with applicable securities laws in connection with any exercise of this Option and (iv) any other agreements required by the Company. If
someone other than Optionee exercises this Option, then such person must submit documentation reasonably acceptable to the Company verifying that such person has the legal right to exercise this Option and such person shall be subject to all of the
restrictions contained herein as if such person were Optionee. 
 4.2 Limitations on Exercise. This Option may
not be exercised unless such exercise is in compliance with all applicable federal and state securities laws, as they are in effect on the date of exercise. 

4.3 Payment. The Exercise Agreement shall be accompanied by full payment of the Exercise Price for the shares
being purchased in cash (by check, Automated Clearing House (“ACH”) or wire transfer), or where permitted by law: 

(a) by cancellation of indebtedness of the Company owed to Optionee; 

(b) by surrender of shares of the Company that are free and clear of all security interests, pledges, liens, claims or encumbrances and:
(i) for which the Company has received “full payment of the purchase price” within the meaning of SEC Rule 144 (and, if such shares were purchased from the Company by use of a promissory note, such note has been fully paid with
respect to such shares) or (ii) that were obtained by Optionee in the public market; 

  
 3 

 (c) by participating in a formal cashless exercise program implemented by the Committee in
connection with the Plan; 
 (d) provided that a public market for the Common Stock exists and subject to compliance with applicable law, by
exercising as set forth below, through a “same day sale” commitment from Optionee and a broker-dealer whereby Optionee irrevocably elects to exercise this Option and to sell a portion of the Shares so purchased sufficient to pay the total
Exercise Price, and whereby the broker-dealer irrevocably commits upon receipt of such Shares to forward the total Exercise Price directly to the Company; or 

(e) by any combination of the foregoing or any other method of payment approved by the Committee that constitutes legal consideration for the
issuance of Shares. 
 For avoidance of uncertainty: ACH transfers that have been received by the Company into its bank account designated for receipt of
such transfers shall be deemed to have been received for all purposes of this Option as of the date on which such transfers were initiated from the Optionee’s account and made irrevocable by Optionee. 

4.4 Tax Withholding. Prior to the issuance of the Shares upon exercise of the Option, Optionee must pay or provide
for foreign, federal, state and local income tax, social insurance, payroll tax, fringe benefits tax, payment on account withholding and other tax-related items related to Optionee’s participation in the
Plan and legally applicable to Optionee, including, as applicable, obligations of the Company (all the foregoing tax-related items, “Tax-Related
Items”). If the Committee permits, Optionee may provide for payment of withholding taxes upon exercise of the Option by requesting that the Company retain the number of Shares with a Fair Market Value equal to the amount of taxes
required to be withheld; or to arrange a mandatory “sell to cover” on Optionee’s behalf (without further authorization); but in no event will the Company withhold Shares or “sell to cover” if such withholding would result in
adverse accounting consequences to the Company. In case of stock withholding or a sell to cover, the Company shall issue the net number of Shares to Optionee by deducting the Shares retained from the Shares issuable upon exercise. The Company may
withhold or account for Tax-Related Items by considering applicable minimum statutory withholding rates or other applicable statutory rates in Optionee’s country, including maximum applicable rates. 

4.5 Issuance of Shares. Provided that the Exercise Agreement and payment are in form and substance satisfactory to
counsel for the Company, the Company shall issue the Shares issuable upon a valid exercise of this Option registered in the name of Optionee, Optionee’s authorized assignee, or Optionee’s legal representative, and shall deliver
certificates representing the Shares with the appropriate legends affixed thereto. 
 5.
COMPLIANCE WITH LAWS AND REGULATIONS. The Plan and this Agreement are intended to comply with Rule 701. Any provision of this Agreement that is inconsistent
with Rule 701 shall, without further act or amendment by the Company or the Committee, be reformed to comply with the requirements of Rule 701. The exercise of this Option and the issuance and transfer of Shares shall be subject to compliance
by the Company and Optionee with all applicable requirements of federal and state securities laws and with all applicable requirements of any stock exchange on which the Common Stock may be listed at the time of such issuance or transfer. Optionee
understands that the Company is under no obligation to register or qualify the Shares with the SEC, any state securities commission or any stock exchange to effect such compliance. 

6. NONTRANSFERABILITY OF OPTION. This Option may not be transferred in any manner
other than by will or by the laws of descent and distribution, and, with respect to NQSOs, by instrument to a testamentary trust in which the options are to be passed to beneficiaries upon the death of the trustor (settlor) or a revocable trust, or
by gift to “immediate family” as that term is defined in 17 C.F.R. 240.16a-1(e), and may be exercised during the lifetime of Optionee only by Optionee or in the event of Optionee’s incapacity,
by Optionee’s legal representative. The terms of this Option shall be binding upon the executors, administrators, successors and assigns of Optionee. 

  
 4 

 7. RESTRICTIONS ON TRANSFER. 

7.1 Disposition of Shares. Optionee hereby agrees that Optionee shall make no disposition of any of the Shares
(other than as permitted by this Agreement) unless and until: 
 (a) Optionee shall have notified the Company of the proposed disposition
and provided a written summary of the terms and conditions of the proposed disposition; 
 (b) Optionee shall have complied with all
requirements of this Agreement applicable to the disposition of the Shares; 
 (c) Optionee shall have provided the Company with written
assurances, in form and substance satisfactory to counsel for the Company, that (i) the proposed disposition does not require registration of the Shares under the Securities Act or under any applicable state securities laws or (ii) all
appropriate actions necessary for compliance with the registration requirements of the Securities Act or of any exemption from registration available under the Securities Act (including Rule 144) or applicable state securities laws have been taken;
and 
 (d) Optionee shall have provided the Company with written assurances, in form and substance satisfactory to the Company, that the
proposed disposition will not result in the contravention of any transfer restrictions applicable to the Shares pursuant to the provisions of the regulations promulgated under Rule 701 or under any other applicable securities laws or adversely
affect the Company’s ability to rely on the exemption(s) from registration under the Securities Act or under any other applicable securities laws for the grant of the Option, the issuance of Shares thereunder or any other issuance of securities
under the Plan. 
 7.2 Restriction on Transfer. Optionee shall not transfer, assign, grant a lien or security
interest in, pledge, hypothecate, encumber or otherwise dispose of any of the Shares which are subject to the Company’s Right of First Refusal described below, except as permitted by this Agreement. 

7.3 Transferee Obligations. Each person (other than the Company) to whom the Shares are transferred by means of
one of the permitted transfers specified in this Agreement must, as a condition precedent to the validity of such transfer, acknowledge in writing to the Company that such person is bound by the provisions of this Agreement and that the transferred
Shares are subject to (i) the Company’s Right of First Refusal granted hereunder and (ii) the market stand-off provisions of Section 8 below, to the same extent such Shares would be so
subject if retained by Optionee. 
 8. MARKET STANDOFF AGREEMENT. Optionee agrees that, subject to any early release
provisions that apply pro rata to stockholders of the Company according to their holdings of Common Stock (determined on an as-converted into Common Stock basis), Optionee will not, for a period of up to one
hundred eighty (180) days (plus up to an additional thirty five (35) days to the extent reasonably requested by the Company or such underwriter(s) to accommodate regulatory restrictions on the publication or other distribution of research
reports or earnings releases by the Company, including NASD and NYSE rules) following the effective date of the registration statement filed with the SEC relating to the initial underwritten sale of Common Stock of the Company to the public under
the Securities Act (the “IPO”), directly or indirectly sell, offer to sell, grant any option for the sale of, or otherwise dispose of any Common Stock or securities convertible into Common Stock, except for:
(i) transfers of Shares permitted under Section 9.6 hereof so long as such transferee furnishes to the Company and the managing underwriter their written consent to be bound by this Section 8 as a condition precedent to such transfer;
and (ii) sales of any securities to be included in the registration statement for the IPO. For the avoidance of doubt, the provisions 

  
 5 

 
of this Section shall only apply to the IPO. The restricted period shall in any event terminate two (2) years after the closing date of the IPO. In order to enforce the foregoing covenant,
the Company shall have the right to place restrictive legends on the certificates representing the Shares subject to this Section and to impose stop transfer instructions with respect to the Shares until the end of such period. Optionee further
agrees to enter into any agreement reasonably required by the underwriters to implement the foregoing restrictions on transfer. For the avoidance of doubt, the foregoing provisions of this Section shall not apply to any registration of securities of
the Company (a) under an employee benefit plan or (b) in a merger, consolidation, business combination or similar transaction. 

9. COMPANY’S RIGHT OF FIRST REFUSAL. Before any Shares held by Optionee or any transferee of such Shares (either sometimes
referred to herein as the “Holder”) may be sold or otherwise transferred (including, without limitation, a transfer by gift or operation of law), the Company and/or its assignee(s) will have a right of first refusal to
purchase the Shares to be sold or transferred (the “Offered Shares”) on the terms and conditions set forth in this Section (the “Right of First Refusal”). 

9.1 Notice of Proposed Transfer. The Holder of the Offered Shares will deliver to the Company a written notice
(the “Notice”) stating: (i) the Holder’s bona fide intention to sell or otherwise transfer the Offered Shares; (ii) the name and address of each proposed purchaser or other transferee (the “Proposed
Transferee”); (iii) the number of Offered Shares to be transferred to each Proposed Transferee; (iv) the bona fide cash price or other consideration for which the Holder proposes to transfer the Offered Shares (the
“Offered Price”); and (v) that the Holder acknowledges this Notice is an offer to sell the Offered Shares to the Company and/or its assignee(s) pursuant to the Company’s Right of First Refusal at the Offered Price
as provided for in this Agreement. 
 9.2 Exercise of Right of First Refusal. At any time within thirty
(30) days after the date of the Notice, the Company and/or its assignee(s) may, by giving written notice to the Holder, elect to purchase all (or, with the consent of the Holder, less than all) the Offered Shares proposed to be transferred to
any one or more of the Proposed Transferees named in the Notice, at the purchase price, determined as specified below. 
 9.3
Purchase Price. The purchase price for the Offered Shares purchased under this Section will be the Offered Price, provided that if the Offered Price consists of no legal consideration (as, for example, in the case
of a transfer by gift) then the purchase price will be the fair market value of the Offered Shares as determined in good faith by the Committee. If the Offered Price includes consideration other than cash, then the value of the non-cash consideration, as determined in good faith by the Committee, will conclusively be deemed to be the cash equivalent value of such non-cash consideration. 

9.4 Payment. Payment of the purchase price for the Offered Shares will be payable, at the option of the Company
and/or its assignee(s) (as applicable), by check or by cancellation of all or a portion of any outstanding purchase money indebtedness owed by the Holder to the Company (or to such assignee, in the case of a purchase of Offered Shares by such
assignee) or by any combination thereof. The purchase price will be paid without interest within sixty (60) days after the Company’s receipt of the Notice, or, at the option of the Company and/or its assignee(s), in the manner and at the
time(s) set forth in the Notice. 
 9.5 Holder’s Right to Transfer. If all of the Offered Shares proposed
in the Notice to be transferred to a given Proposed Transferee are not purchased by the Company and/or its assignee(s) as provided in this Section, then the Holder may sell or otherwise transfer such Offered Shares to each Proposed Transferee at the
Offered Price or at a higher price, provided that (i) such sale or other transfer is consummated within ninety (90) days after the date of the Notice, (ii) any such sale or other transfer is effected in compliance with
all applicable securities laws, and (iii) each Proposed Transferee agrees in writing that the provisions of this Section will continue to apply to the Offered Shares in the hands of such Proposed Transferee. If the Offered Shares described in
the Notice are not transferred to each Proposed Transferee within such ninety (90) day period, then a new Notice must be given to the Company pursuant to which the Company will again be offered the Right of First Refusal before any Shares held
by the Holder may be sold or otherwise transferred. 

  
 6 

 9.6 Exempt Transfers. Notwithstanding anything to the contrary
in this Section, the following transfers of Shares will be exempt from the Right of First Refusal: (i) the transfer of any or all of the Shares during Optionee’s lifetime by gift or on Optionee’s death by will or intestacy to any
member(s) of Optionee’s “Immediate Family” (as defined below) or to a trust for the benefit of Optionee and/or member(s) of Optionee’s Immediate Family, provided that each transferee or other recipient agrees in a
writing satisfactory to the Company that the provisions of this Section will continue to apply to the transferred Shares in the hands of such transferee or other recipient; (ii) any transfer of Shares made pursuant to a statutory merger,
statutory consolidation of the Company with or into another corporation or corporations or a conversion of the Company into another form of legal entity (except that the Right of First Refusal will continue to apply thereafter to such Shares, in
which case the surviving corporation of such merger or consolidation or the resulting entity of such conversion shall succeed to the rights of the Company under this Section unless the agreement of merger or consolidation or conversion expressly
otherwise provides); or (iii) any transfer of Shares pursuant to the winding up and dissolution of the Company. As used herein, the term “Immediate Family” will mean Optionee’s spouse, the lineal descendant or
antecedent, father, mother, brother or sister, child, adopted child, grandchild or adopted grandchild of Optionee or Optionee’s spouse, or the spouse of any of the above or Spousal Equivalent, as defined herein. As used herein, a person is
deemed to be a “Spousal Equivalent” provided the following circumstances are true: (i) irrespective of whether or not Optionee and the Spousal Equivalent are the same sex, they are the sole spousal equivalent of the
other for the last twelve (12) months, (ii) they intend to remain so indefinitely, (iii) neither are married to anyone else, (iv) both are at least 18 years of age and mentally competent to consent to contract, (v) they are not
related by blood to a degree of closeness that which would prohibit legal marriage in the state in which they legally reside, (vi) they are jointly responsible for each other’s common welfare and financial obligations, and (vii) they
reside together in the same residence for the last twelve (12) months and intend to do so indefinitely. 
 9.7 Termination
of Right of First Refusal. The Right of First Refusal will terminate as to all Shares: (i) on the effective date of the first sale of Common Stock of the Company to the general public pursuant to a registration statement
filed with and declared effective by the SEC under the Securities Act (other than a registration statement relating solely to the issuance of Common Stock pursuant to a business combination or an employee incentive or benefit plan); (ii) on any
transfer or conversion of Shares made pursuant to a statutory merger or statutory consolidation of the Company with or into another corporation or corporations if the common stock of the surviving corporation or any direct or indirect parent
corporation thereof is registered under the Exchange Act; or (iii) on any transfer or conversion of Shares made pursuant to a statutory conversion of the Company into another form of legal entity if the common equity (or comparable
equity security) of entity resulting from such conversion is registered under the Exchange Act. 
 9.8 Encumbrances on
Shares. Optionee may grant a lien or security interest in, or pledge, hypothecate or encumber Shares only if each party to whom such lien or security interest is granted, or to whom such pledge, hypothecation or other encumbrance is
made, agrees in a writing satisfactory to the Company that: (i) such lien, security interest, pledge, hypothecation or encumbrance will not adversely affect or impair the Right of First Refusal or the rights of the Company and/or its
assignee(s) with respect thereto and will not apply to such Shares after they are acquired by the Company and/or its assignees under this Section; and (ii) the provisions of this Agreement will continue to apply to such Shares in the hands of
such party and any transferee of such party. 
 10. RIGHTS AS A STOCKHOLDER. Optionee shall not have any of the rights of a
stockholder with respect to any Shares unless and until such Shares are issued to Optionee. Subject to the terms and conditions of this Agreement, Optionee will have all of the rights of a stockholder of the Company with respect to the Shares from
and after the date that Shares are issued to Optionee pursuant to, and in accordance with, the terms of the Exercise Agreement until such time as Optionee disposes of the Shares 

  
 7 

 
or the Company and/or its assignee(s) exercise(s) the Right of First Refusal. Upon an exercise of the Right of First Refusal, Optionee will have no further rights as a holder of the Shares so
purchased upon such exercise, other than the right to receive payment for the Shares so purchased in accordance with the provisions of this Agreement, and Optionee will promptly surrender the stock certificate(s) evidencing the Shares so purchased
to the Company for transfer or cancellation. 
 11. ESCROW. As security for Optionee’s faithful performance of this
Agreement, Optionee agrees, immediately upon receipt of the stock certificate(s) evidencing the Shares, to deliver such certificate(s) to the Secretary of the Company or other designee of the Company (the “Escrow Holder”),
who is hereby appointed to hold such certificate(s) in escrow and to take all such actions and to effectuate all such transfers and/or releases of such Shares as are in accordance with the terms of this Agreement. Optionee and the Company agree that
Escrow Holder will not be liable to any party to this Agreement (or to any other party) for any actions or omissions unless Escrow Holder is grossly negligent or intentionally fraudulent in carrying out the duties of Escrow Holder under this
Agreement. Escrow Holder may rely upon any letter, notice or other document executed with any signature purported to be genuine and may rely on the advice of counsel and obey any order of any court with respect to the transactions contemplated by
this Agreement and will not be liable for any act or omission taken by Escrow Holder in good faith reliance on such documents, the advice of counsel or a court order. The Shares will be released from escrow upon termination of the Right of First
Refusal. 
 12. RESTRICTIVE LEGENDS AND STOP-TRANSFER ORDERS. 

12.1 Legends. Optionee understands and agrees that the Company will place the legends set forth below or similar
legends on any stock certificate(s) evidencing the Shares, together with any other legends that may be required by state or U.S. Federal securities laws, the Company’s Certificate of Incorporation or Bylaws, any other agreement between Optionee
and the Company, or any agreement between Optionee and any third party (and any other legend(s) that the Company may become obligated to place on the stock certificate(s) evidencing the Shares under the terms of any agreement to which the Company is
or may become bound or obligated): 
 (a) THE SECURITIES REPRESENTED HEREBY HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS
AMENDED (THE “SECURITIES ACT”), OR UNDER THE SECURITIES LAWS OF CERTAIN STATES. THESE SECURITIES ARE SUBJECT TO RESTRICTIONS ON TRANSFERABILITY AND RESALE AND MAY NOT BE TRANSFERRED OR RESOLD EXCEPT AS PERMITTED UNDER THE SECURITIES ACT
AND APPLICABLE STATE SECURITIES LAWS, PURSUANT TO REGISTRATION OR EXEMPTION THEREFROM. INVESTORS SHOULD BE AWARE THAT THEY MAY BE REQUIRED TO BEAR THE FINANCIAL RISKS OF THIS INVESTMENT FOR AN INDEFINITE PERIOD OF TIME. THE ISSUER OF THESE
SECURITIES MAY REQUIRE AN OPINION OF COUNSEL IN FORM AND SUBSTANCE SATISFACTORY TO THE ISSUER TO THE EFFECT THAT ANY PROPOSED TRANSFER OR RESALE IS IN COMPLIANCE WITH THE SECURITIES ACT AND ANY APPLICABLE STATE SECURITIES LAWS. 

(b) THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO CERTAIN RESTRICTIONS ON RESALE AND TRANSFER, INCLUDING THE RIGHT OF FIRST
REFUSAL HELD BY THE ISSUER AND/OR ITS ASSIGNEE(S) AS SET FORTH IN A STOCK OPTION AGREEMENT BETWEEN THE ISSUER AND THE ORIGINAL HOLDER OF THESE SHARES, A COPY OF WHICH MAY BE OBTAINED AT THE PRINCIPAL OFFICE OF THE ISSUER. SUCH SALE AND TRANSFER
RESTRICTIONS, INCLUDING THE RIGHT OF FIRST REFUSAL, ARE BINDING ON TRANSFEREES OF THESE SHARES. 

  
 8 

 (c) THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO A MARKET STANDOFF RESTRICTION
AS SET FORTH IN A CERTAIN STOCK OPTION AGREEMENT BETWEEN THE ISSUER AND THE ORIGINAL HOLDER OF THESE SHARES, A COPY OF WHICH MAY BE OBTAINED AT THE PRINCIPAL OFFICE OF THE ISSUER. AS A RESULT OF SUCH AGREEMENT, THESE SHARES MAY NOT BE TRADED PRIOR
TO 180 DAYS AFTER THE EFFECTIVE DATE OF CERTAIN PUBLIC OFFERINGS OF THE COMMON STOCK OF THE ISSUER HEREOF. SUCH RESTRICTION IS BINDING ON TRANSFEREES OF THESE SHARES. 

12.2 Stop-Transfer Instructions. Optionee agrees that, to ensure compliance with the restrictions imposed by this
Agreement, the Company may issue appropriate “stop-transfer” instructions to its transfer agent, if any, and if the Company transfers its own securities, it may make appropriate notations to the same effect in its own records. 

12.3 Refusal to Transfer. The Company will not be required (i) to transfer on its books any Shares that have
been sold or otherwise transferred in violation of any of the provisions of this Agreement or (ii) to treat as owner of such Shares, or to accord the right to vote or pay dividends to any purchaser or other transferee to whom such Shares have
been so transferred. 
 13. CERTAIN TAX CONSEQUENCES. Set forth below is a brief summary as of the Effective Date of the Plan
of some of the federal tax consequences of exercise of the Option and disposition of the Shares. THIS SUMMARY IS NECESSARILY INCOMPLETE, AND THE TAX LAWS AND REGULATIONS ARE SUBJECT TO CHANGE. OPTIONEE SHOULD CONSULT A TAX ADVISER BEFORE EXERCISING
THE OPTION OR DISPOSING OF THE SHARES. 
 13.1 Exercise of ISO. If the Option qualifies as an ISO, there will be
no regular federal income tax liability upon the exercise of the Option, although the excess, if any, of the Fair Market Value of the Shares on the date of exercise over the Exercise Price will be treated as a tax preference item for federal
alternative minimum tax purposes and may subject Optionee to the alternative minimum tax in the year of exercise. 
 13.2
Exercise of Nonqualified Stock Option. If the Option does not qualify as an ISO, there may be a regular federal income tax liability upon the exercise of the Option. Optionee will be treated as having received compensation
income (taxable at ordinary income tax rates) equal to the excess, if any, of the Fair Market Value of the Shares on the date of exercise over the Exercise Price. If Optionee is a current or former employee of the Company, the Company may be
required to withhold from Optionee’s compensation or collect from Optionee and pay to the applicable taxing authorities an amount equal to a percentage of this compensation income at the time of exercise. 

13.3 Disposition of Shares. The following tax consequences may apply upon disposition of the Shares. 

(a) Incentive Stock Options. If the Shares are held for more than twelve (12) months after the date of purchase of the Shares
pursuant to the exercise of an ISO and are disposed of more than two (2) years after the Date of Grant, any gain realized on disposition of the Shares will be treated as long term capital gain for federal income tax purposes. If Shares
purchased under an ISO are disposed of within the applicable one (1) year or two (2) year period, any gain realized on such disposition will be treated as compensation income (taxable at ordinary income rates in the year of the
disposition) to the extent of the excess, if any, of the Fair Market Value of the Shares on the date of exercise over the Exercise Price. 

(b) Nonqualified Stock Options. If the Shares are held for more than twelve (12) months after the date of purchase of the Shares
pursuant to the exercise of an NQSO, any gain realized on disposition of the Shares will be treated as long term capital gain. 

  
 9 

 14. GENERAL PROVISIONS. 

14.1 Interpretation. Any dispute regarding the interpretation of this Agreement shall be submitted by Optionee or
the Company to the Committee for review. The resolution of such a dispute by the Committee shall be final and binding on the Company and Optionee. 

14.2 Entire Agreement. The Plan, the Grant Notice and the Exercise Agreement are each incorporated herein by
reference. This Agreement, the Grant Notice, the Plan and the Exercise Agreement constitute the entire agreement of the parties with respect to the subject matter hereof and supersede all prior undertakings and agreements with respect to such
subject matter. 
 15. NOTICES. Any and all notices required or permitted to be given to a party pursuant to the provisions of
this Agreement will be in writing and will be effective and deemed to provide such party sufficient notice under this Agreement on the earliest of the following: (i) at the time of personal delivery, if delivery is in person; (ii) at the
time an electronic confirmation of receipt is received, if delivery is by email; (iii) at the time of transmission by facsimile, addressed to the other party at its facsimile number specified herein (or hereafter modified by subsequent notice
to the parties hereto), with confirmation of receipt made by both telephone and printed confirmation sheet verifying successful transmission of the facsimile; (iv) one (1) business day after deposit with an express overnight courier for United
States deliveries, or two (2) business days after such deposit for deliveries outside of the United States, with proof of delivery from the courier requested; or (v) three (3) business days after deposit in the United States mail by
certified mail (return receipt requested) for United States deliveries. Any notice for delivery outside the United States will be sent by email, facsimile or by express courier. Any notice not delivered personally or by email will be sent with
postage and/or other charges prepaid and properly addressed to Optionee at the last known address or facsimile number on the books of the Company, or at such other address or facsimile number as such other party may designate by one of the indicated
means of notice herein to the other parties hereto or, in the case of the Company, to it at its principal place of business. Notices to the Company will be marked “Attention: Chief Financial Officer.” Notices by facsimile shall be machine
verified as received. 
 16. SUCCESSORS AND ASSIGNS. The Company may assign any of its rights under this Agreement including
its rights to purchase Shares under the Right of First Refusal. This Agreement shall be binding upon and inure to the benefit of the successors and assigns of the Company. Subject to the restrictions on transfer set forth herein, this Agreement
shall be binding upon Optionee and Optionee’s heirs, executors, administrators, legal representatives, successors and assigns. 

17. GOVERNING LAW. This Agreement shall be governed by and construed in accordance with the internal laws of the State of
Delaware as such laws are applied to agreements between Delaware residents entered into and to be performed entirely within Delaware. If any provision of this Agreement is determined by a court of law to be illegal or unenforceable, then such
provision will be enforced to the maximum extent possible and the other provisions will remain fully effective and enforceable. 

18. FURTHER ASSURANCES. The parties agree to execute such further documents and instruments and to take such further
actions as may be reasonably necessary to carry out the purposes and intent of this Agreement. 
 19. TITLES AND HEADINGS.
The titles, captions and headings of this Agreement are included for ease of reference only and will be disregarded in interpreting or construing this Agreement. Unless otherwise specifically stated, all references herein to “sections”
and “exhibits” will mean “sections” and “exhibits” to this Agreement. 
 20. COUNTERPARTS.
This Agreement may be executed in any number of counterparts, each of which when so executed and delivered will be deemed an original, and all of which together shall constitute one and the same agreement. 

  
 10 

 21. SEVERABILITY. If any provision of this Agreement is determined by
any court or arbitrator of competent jurisdiction to be invalid, illegal or unenforceable in any respect, such provision will be enforced to the maximum extent possible given the intent of the parties hereto. If such clause or provision cannot be so
enforced, such provision shall be stricken from this Agreement and the remainder of this Agreement shall be enforced as if such invalid, illegal or unenforceable clause or provision had (to the extent not enforceable) never been contained in this
Agreement. Notwithstanding the forgoing, if the value of this Agreement based upon the substantial benefit of the bargain for any party is materially impaired, which determination as made by the presiding court or arbitrator of competent
jurisdiction shall be binding, then both parties agree to substitute such provision(s) through good faith negotiations. 
 * * * * * 

Attachment: Annex A: Form of Stock Option Exercise Notice and Agreement 

  
 11 

 ANNEX A 

FORM OF STOCK OPTION EXERCISE NOTICE AND AGREEMENT 

 STOCK OPTION EXERCISE NOTICE AND AGREEMENT 

PRELUDE THERAPEUTICS INCORPORATED 

2016 STOCK INCENTIVE PLAN 

*NOTE: You must sign this Notice on Page 3 before submitting it to Prelude Therapeutics Incorporated (the “Company”).

 OPTIONEE INFORMATION: Please provide the following information about yourself
(“Optionee”): 
  

									
	Name:	 	  
	 		  	Social Security Number:	 	
                     

					
	Address:	 	
                 
	 	        	  	Employee Number:	 	              

					
		 	              
	 		  	Email Address:	 	  

 OPTION INFORMATION: Please provide this information on the option being exercised
(the “Option”): 
  

			
	Grant No.	  	
		
	Date of Grant:	  	Type of Stock Option:
		
	Option Price per Share: $____	  	☐ Nonqualified (NQSO)
		
	Total number of shares of Common Stock of the Company subject to the Option:	  	☐ Incentive (ISO)

 EXERCISE INFORMATION: 

Number of shares of Common Stock of the Company for which the Option is now being exercised [________________]. (These shares are referred to below as the
“Purchased Shares.”) 
 Total Exercise Price Being Paid for the Purchased Shares: $____________ 

Form of payment enclosed [check all that apply]: 
  

	☐	 Check for $____________, payable to “Prelude Therapeutics Incorporated.”

  

	☐	 Certificate(s) for ________________ shares of Common Stock of the Company. These shares will be valued as of
the date this notice is received by the Company. [Requires Company consent.] 

  

	☐	 Automated Clearing House (“ACH”) transfer in the amount of $___________.

 AGREEMENTS, REPRESENTATIONS AND ACKNOWLEDGMENTS OF
OPTIONEE: By signing this Stock Option Exercise Notice and Agreement, Optionee hereby agrees with, and represents to, the Company as follows: 
  

	1.	 Terms Governing. I acknowledge and agree with the Company that I am acquiring the Purchased Shares by
exercise of this Option subject to all other terms and conditions of the Notice of Stock Option Grant and the Stock Option Agreement that govern the Option, including without limitation the terms of the Company’s 2016 Stock Incentive Plan, as
it may be amended (the “Plan”). 

  

	2.	 Investment Intent; Securities Law Restrictions. I represent and warrant to the Company that I am
acquiring and will hold the Purchased Shares for investment for my account only, and not with a view to, or for resale in connection with, any “distribution” of the Purchased Shares within the meaning of the Securities Act of 1933, as
amended (the “Securities Act”). I understand that the Purchased Shares 

 have not been registered under the Securities Act by reason of a specific exemption from
such registration requirement and that the Purchased Shares must be held by me indefinitely, unless they are subsequently registered under the Securities Act or I obtain an opinion of counsel (in form and substance satisfactory to the Company and
its counsel) that registration is not required. I acknowledge that the Company is under no obligation to register the Purchased Shares under the Securities Act or under any other securities law. 

 

	3.	 Restrictions on Transfer: Rule 144. I will not sell, transfer or otherwise dispose of the Purchased
Shares in violation of the Securities Act, the Securities Exchange Act of 1934, or the rules promulgated thereunder (including Rule 144 under the Securities Act described below (“Rule 144”)) or of any other applicable
securities laws. I am aware of Rule 144, which permits limited public resales of securities acquired in a non-public offering, subject to satisfaction of certain conditions, which include (without
limitation) that: (a) certain current public information about the Company is available; (b) the resale occurs only after the holding period required by Rule 144 has been met; (c) the sale occurs through an unsolicited
“broker’s transaction”; and (d) the amount of securities being sold during any three-month period does not exceed specified limitations. I understand that the conditions for resale set forth in Rule 144 have not been
satisfied and that the Company has no plans to satisfy these conditions in the foreseeable future. 

  

	4.	 Access to Information; Understanding of Risk in Investment. I acknowledge that I have received and had
access to such information as I consider necessary or appropriate for deciding whether to invest in the Purchased Shares and that I had an opportunity to ask questions and receive answers from the Company regarding the terms and conditions of the
issuance of the Purchased Shares. I am aware that my investment in the Company is a speculative investment that has limited liquidity and is subject to the risk of complete loss. I am able, without impairing my financial condition, to hold the
Purchased Shares for an indefinite period and to suffer a complete loss of my investment in the Purchased Shares. 

  

	5.	 Rights of First Refusal; Market Stand-off. I acknowledge that
the Purchased Shares remain subject to the Company’s Right of First Refusal and the market stand-off covenants (sometimes referred to as the “lock-up”),
all in accordance with the applicable Notice of Stock Option Grant and the Stock Option Agreement that govern the Option. 

  

	6.	 Form of Ownership. I acknowledge that the Company has encouraged me to consult my own adviser to
determine the form of ownership of the Purchased Shares that is appropriate for me. In the event that I choose to transfer my Purchased Shares to a trust, I agree to sign a Stock Transfer Agreement. In the event that I choose to transfer my
Purchased Shares to a trust that is not an eligible revocable trust, I also acknowledge that the transfer will be treated as a “disposition” for tax purposes. As a result, the favorable ISO tax treatment will be unavailable and other
unfavorable tax consequences may occur. 

  

	7.	 Investigation of Tax Consequences. I acknowledge that the Company has encouraged me to consult my own
adviser to determine the tax consequences of acquiring the Purchased Shares at this time. 

  

	8.	 Other Tax Matters. I agree that the Company does not have a duty to design or administer the Plan or its
other compensation programs in a manner that minimizes my tax liabilities. I will not make any claim against the Company or its Board, officers or employees related to tax liabilities arising from my options or my other compensation. In particular,
I acknowledge that my options (including the Option) are exempt from section 409A of the Internal Revenue Code only if the exercise price per share is at least equal to the fair market value per share of the Common Stock at the time the option was
granted by the Board. Since shares of the Common Stock are not traded on an established securities market, the determination of their fair market value was made by the Board and/or by an independent valuation firm retained by the Company. I
acknowledge that there is no guarantee in either case that the Internal Revenue Service will agree with the valuation, and I will not make any claim against the Company or its Board, officers or employees in the event that the Internal Revenue
Service asserts that the valuation was too low. 

  
 2 

	9.	 Spouse Consent. I agree to seek the consent of my spouse to the extent required by the Company to
enforce the foregoing. 

  

	10.	 Tax Withholding. As a condition of exercising this Option, I agree to make adequate provision for
foreign, federal, state or other tax withholding obligations, if any, which arise upon the grant, vesting or exercise of this Option, or disposition of the Purchased Shares, whether by withholding, direct payment to the Company, or otherwise.

 The undersigned hereby executes and delivers this Stock Option Exercise Notice and Agreement and agrees to be bound by its terms 

 

					
	SIGNATURE:	  	      	  	DATE:
			
	
                     
                
	  		  	  

	Optionee’s Name:	  		  	

 [Signature Page to Stock Option Exercise Notice and Agreement] 

  
 3 

 PRELUDE THERAPEUTICS INCORPORATED 

2016 STOCK INCENTIVE PLAN 

RESTRICTED STOCK PURCHASE AGREEMENT 

This Restricted Stock Purchase Agreement (the “Agreement”) is made and entered into as of _________________
(the “Effective Date”) by and between Prelude Therapeutics Incorporated, a Delaware corporation (the “Company”), and _____________
(“Purchaser”). Capitalized terms not defined herein shall have the meanings ascribed to them in the Company’s 2016 Stock Incentive Plan, as may be amended from time to time (the “Plan”). 

1. PURCHASE OF SHARES. 

1.1 Agreement to Purchase and Sell Shares. On the
Effective Date and subject to the terms and conditions of this Agreement and the Plan, Purchaser hereby purchases from the Company, and the Company hereby sells to Purchaser, _____________ (_______) shares of the Company’s Common Stock
(the “Shares”), at the price of ___________($____) per share (the “Purchase Price Per Share”) for a Total Purchase Price of ___________($________) (the
“Purchase Price”). As used in this Agreement, the term “Shares” includes the Shares purchased under this Agreement and all securities received (a) in replacement
of the Shares, (b) as a result of stock dividends or stock splits with respect to the Shares, and (c) in replacement of the Shares in a merger, recapitalization, reorganization or similar corporate transaction. 

1.2 Payment. Purchaser hereby delivers payment of the Purchase Price as follows (check and complete as
appropriate): 
  

	☐	 in cash (by check) in the amount of $__________, receipt of which is acknowledged by the Company.

  

	☐	 by Automated Clearing House (“ACH”) transfer in the amount of $______, receipt of which
is acknowledged by the Company. 

  

	☐	 by cancellation of indebtedness of the Company owed to Purchaser in the amount of $____________.

  

	☐	 by the waiver hereby of compensation due or accrued for services rendered in the amount of
$_____________________. 

  

	☐	 by delivery of _________ fully-paid, nonassessable and vested shares of the Common Stock of the Company owned
by Purchaser free and clear of all liens, claims, encumbrances or security interests, valued at the current Fair Market Value of $___________ per share (a) for which the Company has received “full payment of the purchase price” within
the meaning of SEC Rule 144, (if purchased by use of a promissory note, such note has been fully paid with respect to such vested shares), or (b) that were obtained by Purchaser in the open public market. 

For avoidance of uncertainty: ACH transfers that have been successfully received by the Company into its bank account designated for receipt of such transfers
shall be deemed to have been received for all purposes of this Agreement as of the date on which such transfers were initiated from the Purchaser’s account and made irrevocable by Purchaser. 

2. DELIVERIES. 

2.1 Deliveries by the Purchaser. Purchaser hereby delivers to the Company at its principal executive offices:
(a) this completed and signed Agreement, and (b) the Purchase Price, paid by delivery of the form of payment specified in Section 1.2. 

  
 1 

 2.2 Deliveries by the Company. Upon its receipt of the Purchase
Price, payment or other provision for any applicable tax obligations, if any, and all the documents to be executed and delivered by Purchaser to the Company as provided herein, the Company will issue a duly executed stock certificate evidencing the
Shares in the name of Purchaser with the appropriate legends affixed thereto, to be placed in escrow as provided in Section 7.2 to secure performance of Purchaser’s obligations under Sections 5 and 6 until expiration or termination
of the Company’s Repurchase Option and Refusal Right (as such terms are defined in Sections 5 and 6, respectively). 
 3.
REPRESENTATIONS AND WARRANTIES OF PURCHASER. Purchaser represents and warrants to the Company as follows. 
 3.1 Agrees
to Terms of the Plan. Purchaser has received a copy of the Plan, has read and understands the terms of the Plan and this Agreement, and agrees to be bound by their terms and conditions. 

3.2 Acknowledgment of Tax Risks. Purchaser acknowledges that there may be adverse tax consequences upon the
purchase and the disposition of the Shares, and that Purchaser has been advised by the Company to consult a tax adviser prior to such purchase or disposition. Purchaser further acknowledges that Purchaser is not relying on the Company or its counsel
for tax advice regarding Purchaser’s purchaser or disposition of the Shares or the tax consequences to Purchaser of this Agreement. 

3.3 Shares Not Registered or Qualified. Purchaser understands and acknowledges that the Shares have not been
registered with the SEC under the Securities Act, or with any securities regulatory agency administering any state securities laws, and that, notwithstanding any other provision of this Agreement to the contrary, the purchase of any Shares is
expressly conditioned upon compliance with the Securities Act and all applicable state securities laws. Purchaser agrees to cooperate with the Company to ensure compliance with such laws. 

3.4 No Transfer Unless Registered or Exempt; Contractual Restrictions on Transfers. Purchaser understands that
Purchaser may not transfer any Shares unless such Shares are registered under the Securities Act or qualified under applicable state securities laws or unless, in the opinion of counsel to the Company, exemptions from such registration and
qualification requirements are available. Purchaser understands that only the Company may file a registration statement with the SEC and that the Company is under no obligation to do so with respect to the Shares. Purchaser has also been advised
that exemptions from registration and qualification may not be available or may not permit Purchaser to transfer all or any of the Shares in the amounts or at the times proposed by Purchaser. Purchaser further acknowledges that this Agreement
imposes additional restrictions on transfer of the Shares. 
 3.5 SEC Rule 701. Shares that are issued pursuant
to SEC Rule 701 promulgated under the Securities Act may become freely tradable by non-affiliates (under limited conditions regarding the method of sale) ninety (90) days after the first sale of
Common Stock of the Company to the general public pursuant to a registration statement filed with and declared effective by the SEC, subject to the lengthier market standoff agreement contained in Section 4 of this Agreement or any other
agreement entered into by Purchaser. Affiliates must comply with the provisions (other than the holding period requirements) of Rule 144 which permits certain limited sales of unregistered securities. Rule 144 is not presently available with
respect to the Shares and, in any event, requires that the Shares be held for a minimum of six (6) months, and in certain cases one (1) year, after they have been purchased and paid for (within the meaning of Rule 144). Purchaser
understands that use of a promissory note as payment for the Shares may not be deemed to be “full payment of the purchase price” within the meaning of Rule 144 unless certain conditions are met and that, accordingly, the Rule 144 holding
period of such Shares may not begin to run until such Shares are fully paid for within the meaning of Rule 144. Purchaser understands that Rule 144 may indefinitely restrict transfer of the Shares so long as Purchaser remains an
“affiliate” of the Company or if “current public information” about the Company (as defined in Rule 144) is not publicly available. 

  
 2 

 3.6 Access to Information. Purchaser has had access to all
information regarding the Company and its present and prospective business, assets, liabilities and financial condition that Purchaser reasonably considers important in making the decision to purchase the Shares, and Purchaser has had ample
opportunity to ask questions of the Company’s representatives concerning such matters and this investment. 
 3.7
Understanding of Risks. Purchaser is fully aware of: (a) the highly speculative nature of the investment in the Shares; (b) the financial hazards involved; (c) the lack of liquidity of the Shares and the
restrictions on transferability of the Shares (e.g., that Purchaser may not be able to sell or dispose of the Shares or use them as collateral for loans); (d) the qualifications and backgrounds of the management of the Company; and
(e) the tax consequences of investment in, and disposition of, the Shares. 
 3.8 Purchase for Own Account for
Investment. Purchaser is purchasing the Shares for Purchaser’s own account for investment purposes only and not with a view to, or for sale in connection with, a distribution of the Shares within the meaning of the Securities
Act. Purchaser has no present intention of selling or otherwise disposing of all or any portion of the Shares and no one other than Purchaser has any beneficial ownership of any of the Shares. 

3.9 No General Solicitation. At no time was Purchaser presented with or solicited by any publicly issued or
circulated newspaper, mail, radio, television or other form of general advertising or solicitation in connection with the offer, sale and purchase of the Shares. 

3.10 SEC Rule 144. Purchaser has been advised that SEC Rule 144 promulgated under the Securities Act, which
permits certain limited sales of unregistered securities, is not presently available with respect to the Shares and, in any event, requires that the Shares be held for a minimum of six (6) months, and in certain cases one (1) year, after
they have been purchased and paid for (within the meaning of Rule 144), subject to the lengthier market standoff agreement contained in Section 4 of this Agreement or any other agreement entered into by Purchaser. Purchaser
understands that Rule 144 may indefinitely restrict transfer of the Shares so long as Purchaser remains an “affiliate” of the Company or if “current public information” about the Company (as defined in Rule 144) is not publicly
available. 
 4. MARKET STANDOFF AGREEMENT. Subject to the provisions of this Section, Purchaser agrees in connection with any
registration of the Company’s securities under the Securities Act or other registered public offering that, Purchaser will not sell or otherwise dispose of any Shares without the prior written consent of the Company or such managing
underwriters, as the case may be, for a period of time (not to exceed one hundred eighty (180) days) after the effective date of such registration requested by such managing underwriters and subject to all restrictions as the Company or the
managing underwriters may specify for employee-stockholders generally; provided however, that if during the last seventeen (17) days of the restricted period the Company issues an earnings release or material news, or a material
event relating to the Company occurs, or prior to the expiration of the restricted period the Company announces that it will release earnings results during the sixteen (16)-day period beginning on the last
day of the restricted period, then, if required by the underwriters or the Company, for so long as, and to the extent that, Rule 2711 or any successor rule of the Financial Industry Regulatory Authority applies, the restrictions imposed by
this Section 4 shall continue to apply until the expiration of the 18-day period beginning on the issuance of the earnings release or the occurrence of the material news or material event. The restricted
period shall in any event terminate two (2) years after the closing date of the Company’s initial public offering. For purposes of this Section 4, the term “Company” shall include any wholly-owned subsidiary of the Company
into which the Company merges or consolidates. In order to enforce the foregoing covenant, the Company shall have the right to place restrictive legends on the certificates representing the shares subject to this Section and to impose stop transfer
instructions with respect to the Shares until the end of such period. Purchaser further agrees that the underwriters of any such registered public offering shall be third party beneficiaries of this Section 4 and agrees to enter into any
agreement reasonably required by the underwriters to implement the foregoing. Notwithstanding anything in this Section to the contrary, for the avoidance of doubt, the foregoing provisions of this Section shall not apply to any registration of
securities of the Company (a) under an employee benefit plan or (b) in a merger, consolidation, business combination or similar transaction.  

  
 3 

 5. COMPANY’S REPURCHASE OPTION FOR UNVESTED SHARES. The Company, or
(subject to Section 5.6) its assignee, shall have the option to repurchase all or a portion of the Purchaser’s Shares that are Unvested Shares (as defined below) on the Termination Date on the terms and conditions set forth in this Section
(the “Repurchase Option”) if Purchaser is Terminated (as defined in the Plan) for any reason, or no reason, including without limitation, Purchaser’s death, Disability (as defined in the Plan), voluntary resignation or
termination by the Company with or without Cause. 
 5.1 Termination and Termination Date. In case of any
dispute as to whether Purchaser is Terminated, the Committee shall have discretion to determine in good faith whether Purchaser has been Terminated and the effective date of such Termination (the “Termination Date”). 

5.2 Vested and Unvested Shares. Shares that are vested pursuant to the schedule set forth in this Section 5.2
are “Vested Shares.” Shares that are not vested pursuant to such schedule are “Unvested Shares.” On the Effective Date, ________________ of the Shares will be Unvested Shares (the
“Initial Unvested Shares”). Provided Purchaser continues to provide services to the Company or any Subsidiary or Parent of the Company at all times from the Effective Date until ________________ (the “First Vesting
Date”), then on the First Vesting Date one-fourth (1/4th) of the Initial Unvested Shares will become Vested Shares, and on the same day
of each succeeding calendar month thereafter (or if there is no such day in any month, then the last day of such calendar month), an additional one forty-eighth 1/48th of the Initial Unvested
Shares shall vest until the earliest to occur of (a) the date all of the Shares are Vested Shares, (b) the Termination Date or (c) the date vesting otherwise terminates pursuant to this Agreement or the Plan. No fractional Shares
shall be issued. No Shares will become Vested Shares after the Termination Date. The number of the Shares that are Vested Shares or Unvested Shares will be proportionally adjusted to reflect any stock split, reverse stock split or similar change in
the capital structure of the Company as set forth in Section 2.2 of the Plan occurring after the Effective Date. 
 5.3
Exercise of Repurchase Option. At any time within ninety (90) days after the Purchaser’s Termination Date, the Company, or its assignee, may, at its option, elect to repurchase any or all the Purchaser’s Shares
that are Unvested Shares on the Termination Date by giving Purchaser written notice of exercise of the Repurchase Option, specifying the number of Unvested Shares to be repurchased. Such Unvested Shares shall be repurchased at the Purchase Price Per
Share, proportionately adjusted for any stock split, reverse stock split or similar change in the capital structure of the Company as set forth in Section 2.2 of the Plan occurring after the Effective Date (the “Repurchase
Price”). The Repurchase Price shall be payable, at the option of the Company or its assignee, by check or by cancellation of all or a portion of any outstanding indebtedness owed by Purchaser to the Company and/or such assignee, or by
any combination thereof. The Repurchase Price shall be paid without interest within the term of the Repurchase Option as described in the first sentence of this Section 5.3. The Company may, at its option, decline to exercise its Repurchase
Option or may exercise its Repurchase Option only with respect to a portion of the Unvested Shares. 
 5.4 Right of Termination
Unaffected. Nothing in this Agreement shall be construed to limit or otherwise affect in any manner whatsoever the right or power of the Company (or any Parent or Subsidiary of the Company) to terminate Purchaser’s employment or
other relationship with Company (or the Parent or Subsidiary of the Company) at any time, for any reason or no reason, with or without Cause. 

5.5 Additional or Exchanged Securities and Property. Subject to the provisions of Section 5.2 above, in the
event of a merger or consolidation of the Company with or into another entity, any other corporate reorganization, a stock split, the declaration of a stock dividend, the declaration of an extraordinary dividend payable in a form other than stock, a
spin-off, a recapitalization or a similar transaction affecting the Company’s outstanding securities, any securities or other property (including cash or cash equivalents) that are by reason of such
transaction exchanged for, or distributed or issued with 

  
 4 

 
respect to, any Unvested Shares shall immediately be subject to the Repurchase Option. Appropriate adjustments shall be made to the price per share to be paid for Unvested Shares upon the
exercise of the Repurchase Option (by allocating such price among the Unvested Shares and such other securities or property), provided that the aggregate purchase price payable for the Unvested Shares and all such other securities and
property shall remain the same price that was original payable under the Repurchase Option to repurchase such Unvested Shares. Subject to the provisions of Section 5.2 above, in the event of a merger or consolidation of the Company with or into
another entity or any other corporate reorganization, the Repurchase Option may be exercised by the Company’s successor. 
 5.6
Assignment of Repurchase Right. The Company may freely assign the Company’s Repurchase Option, in whole or in part, provided that any person who accepts an assignment of the Repurchase Option from the Company shall assume
all of the Company’s rights and obligations with respect to the Repurchase Option (to the extent so assigned) under this Agreement. 

6. COMPANY’S REFUSAL RIGHT. Unvested Shares shall be subject to the restrictions on transfer and the granting of
encumbrances thereon as provided in Section 7 hereof. Before any Vested Shares (as defined in Section 5 hereof) held by Purchaser or any transferee of such Vested Shares (either sometimes referred to herein as the
“Holder”) may be sold or otherwise transferred (including, without limitation, a transfer by gift or operation of law), the Company and/or its assignee(s) will have a right of first refusal to purchase the Vested Shares to be
sold or transferred (the “Offered Shares”) on the terms and conditions set forth in this Section (the “Refusal Right”). 

6.1 Notice of Proposed Transfer. The Holder of the Offered Shares will deliver to the Company a written notice
(the “Notice”) stating: (a) the Holder’s bona fide intention to sell or otherwise transfer the Offered Shares; (b) the name and address of each proposed purchaser or other transferee of Offered Shares
(“Proposed Transferee”); (c) the number of Offered Shares to be transferred to each Proposed Transferee; (d) the bona fide cash price or other consideration for which the Holder proposes to transfer the Offered Shares to
each Proposed Transferee (the “Offered Price”); and (e) that the Holder acknowledges this Notice is an offer to sell the Offered Shares to the Company and/or its assignee(s) pursuant to the Company’s Refusal Right
at the Offered Price as provided for in this Agreement. 
 6.2 Exercise of Refusal Right. At any time within
thirty (30) days after the date the Notice is effective pursuant to Section 9.2, the Company and/or its assignee(s) may, by giving written notice to the Holder, elect to purchase all (or, with the consent of the Holder, less than all) the
Offered Shares proposed to be transferred to any one or more of the Proposed Transferees named in the Notice, at the purchase price, determined as provided in Section 6.3 below. 

6.3 Purchase Price. The purchase price for the Offered Shares purchased under this Section will be the Offered
Price, provided that if the Offered Price consists of no legal consideration (as, for example, in the case of a transfer by gift), then the purchase price will be the fair market value of the Offered Shares as determined in good
faith by the Company’s Board of Directors. If the Offered Price includes consideration other than cash, then the value of the non-cash consideration, as determined in good faith by the Company’s
Board of Directors, will conclusively be deemed to be the cash equivalent value of such non-cash consideration. 

6.4 Payment. The purchase price for the Offered Shares will be paid, at the option of the Company and/or its
assignee(s) (as applicable), by check or by cancellation of all or a portion of any outstanding indebtedness owed by the Holder to the Company (or to such assignee, in the case of a purchase of Offered Shares by such assignee) or by any combination
thereof. The purchase price will be paid without interest within sixty (60) days after the Company’s receipt of the Notice, or, at the option of the Company and/or its assignee(s), in the manner and at the time(s) set forth in the Notice.

  
 5 

 6.5 Holder’s Right to Transfer. If all of the Offered
Shares proposed in the Notice to be transferred to a given Proposed Transferee are not purchased by the Company and/or its assignee(s) as provided in this Section, then the Holder may sell or otherwise transfer such Offered Shares to such Proposed
Transferee at the Offered Price or at a higher price, provided that (a) such sale or other transfer is consummated within one hundred twenty (120) days after the date the Notice is effective pursuant to Section 9.2, (b)
any such sale or other transfer is effected in compliance with all applicable securities laws, and (c) such Proposed Transferee agrees in writing that the provisions of this Section will continue to apply to the Offered Shares in the hands of
such Proposed Transferee. If the Offered Shares described in the Notice are not transferred to such Proposed Transferee within such one hundred twenty (120) day period, then a new Notice must be given to the Company pursuant to which the
Company will again be offered the Refusal Right before any Shares held by the Holder may be sold or otherwise transferred. 
 6.6
Exempt Transfers. Notwithstanding the foregoing, the following transfers of Vested Shares will be exempt from the Refusal Right: (a) the transfer of any or all of the Vested Shares during Purchaser’s lifetime by gift
or on Purchaser’s death by will or intestacy to Purchaser’s “Immediate Family” (as defined below) or to a trust for the benefit of Purchaser or Purchaser’s Immediate Family, provided that each transferee agrees
in a writing satisfactory to the Company that the provisions of this Section will continue to apply to the transferred Vested Shares in the hands of such transferee; (b) any transfer of Vested Shares made pursuant to a statutory merger or
statutory consolidation of the Company with or into another entity or entities (except that, subject to Section 6.7, unless the agreement of merger or consolidation expressly otherwise provides, the Refusal Right will continue to apply
thereafter to such Vested Shares, in which case the surviving entity of such merger or consolidation shall succeed to the rights of the Company under this Section); or (c) any transfer of Vested Shares pursuant to the winding up and dissolution
of the Company. As used herein, the term “Immediate Family” will mean Purchaser’s spouse, the lineal descendant or antecedent, father, mother, brother or sister, child, adopted child, grandchild or adopted grandchild of
Purchaser or Purchaser’s spouse, or the spouse of any of the above or Spousal Equivalent, as defined herein. As used herein, a person is deemed to be a “Spousal Equivalent” provided the following circumstances are true:
(i) irrespective of whether or not the Purchaser and the Spousal Equivalent are the same sex, they are the sole spousal equivalent of the other for the last twelve (12) months, (ii) they intend to remain so indefinitely, (iii) neither
are married to anyone else, (iv) both are at least 18 years of age and mentally competent to consent to contract, (v) they are not related by blood to a degree of closeness that which would prohibit legal marriage in the state in which
they legally reside, (vi) they are jointly responsible for each other’s common welfare and financial obligations, and (vii) they reside together in the same residence for the last twelve (12) months and intend to do so
indefinitely. 
 6.7 Termination of Refusal Right. The Refusal Right will terminate as to all Shares:
(a) on the effective date of the first sale of Common Stock of the Company to the public pursuant to a registration statement filed with and declared effective by the SEC under the Securities Act or, if expressly approved by the Board as
terminating the Refusal Right, under the laws of any other country having substantially the same effect (other than a registration statement relating solely to the issuance of Common Stock pursuant to a business combination or an employee incentive
or benefit plan) or (b) on any transfer or conversion of Shares made pursuant to a statutory merger or statutory consolidation of the Company with or into another entity or entities if the common stock of the surviving entity or any direct or
indirect parent entity thereof is registered under the Securities Exchange Act of 1934, as amended. 
 7. ADDITIONAL RESTRICTIONS UPON
SHARE OWNERSHIP OR TRANSFER. 
 7.1 Rights as a Stockholder. Subject to the terms and conditions of this
Agreement, Purchaser will have all of the rights of a Stockholder of the Company with respect to the Shares from and after the date that Shares are issued to Purchaser until such time as Purchaser disposes of the Shares or the Company and/or its
assignee(s) exercise(s) the Refusal Right or the Repurchase Option. Upon an exercise of the Refusal Right or the Repurchase Option, Purchaser will have no further rights as a holder of the Shares so purchased upon such exercise, other than the right
to receive payment for the Shares so purchased in accordance with the provisions of this Agreement, and Purchaser will promptly surrender the stock certificate(s) evidencing the Shares so purchased to the Company for transfer or cancellation. 

  
 6 

 7.2 Escrow. As security for Purchaser’s faithful
performance of this Agreement, Purchaser agrees, immediately upon receipt of the stock certificate(s) evidencing the Shares, to deliver such certificate(s) to the Secretary of the Company or other designee of the Company (the “Escrow
Holder”), who is hereby appointed to hold such certificate(s) in escrow and to take all such actions and to effectuate all such transfers and/or releases of such Shares as are in accordance with the terms of this Agreement. Purchaser
and the Company agree that Escrow Holder will not be liable to any party to this Agreement (or to any other person or entity) for any actions or omissions unless Escrow Holder is grossly negligent or intentionally fraudulent in carrying out the
duties of Escrow Holder under this Agreement. Escrow Holder may rely upon any letter, notice or other document executed with any signature purported to be genuine and may rely on the advice of counsel and obey any order of any court with respect to
the transactions contemplated by this Agreement. The Shares will be released from escrow upon termination of both the Refusal Right and the Repurchase Option. 

7.3 Encumbrances on Shares. Without the Company’s prior written consent given with the approval of the
Company’s Board of Directors, Purchaser may not grant a lien or security interest in, or pledge, hypothecate or encumber, any Unvested Shares. 

7.4 Restrictions on Transfers. Unvested Shares may not be sold or otherwise transferred by Purchaser without the
Company’s prior written consent. Purchaser hereby agrees that Purchaser shall make no disposition of the Shares (other than as permitted by this Agreement) unless and until: 

(a) Purchaser shall have notified the Company of the proposed disposition and provided a written summary of the terms and
conditions of the proposed disposition; 
 (b) Purchaser shall have complied with all requirements of this Agreement
applicable to the disposition of the Shares, including but not limited to the Refusal Right, the Market Standoff and the Repurchase Option; and 

(c) Purchaser shall have provided the Company with written assurances, in form and substance satisfactory to counsel for the
Company, that (i) the proposed disposition does not require registration of the Shares under the Securities Act or under any state securities laws, and (ii) all appropriate actions necessary for compliance with the registration and
qualification requirements of the Securities Act and any state securities laws, or of any exemption from registration or qualification, available thereunder (including Rule 144) have been taken. 

Each person (other than the Company) to whom the Shares are transferred by means of one of the permitted transfers specified in this Agreement must, as a
condition precedent to the validity of such transfer, acknowledge in writing to the Company that such person is bound by the provisions of this Agreement and that the transferred Shares are subject to the Company’s Refusal Right or the
Repurchase Option granted hereunder and the market stand-off provisions of Section 4 hereof, to the same extent such Shares would be so subject if retained by the Purchaser. 

7.5 Restrictive Legends and Stop-transfer Orders. Purchaser understands and agrees that the Company will place the
legends set forth below or similar legends on any stock certificate(s) evidencing the Shares, together with any other legends that may be required by applicable laws, the Company’s Certificate of Incorporation or Bylaws, any other agreement
between Purchaser and the Company or any agreement between Purchaser and any third party: 
 THE SECURITIES REPRESENTED HEREBY HAVE NOT
BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “SECURITIES ACT”), OR UNDER THE SECURITIES LAWS OF CERTAIN STATES. THESE SECURITIES ARE SUBJECT TO RESTRICTIONS ON TRANSFERABILITY AND RESALE AND MAY NOT BE TRANSFERRED OR
RESOLD EXCEPT AS 

  
 7 

 
PERMITTED UNDER THE SECURITIES ACT AND APPLICABLE STATE SECURITIES LAWS, PURSUANT TO REGISTRATION OR EXEMPTION THEREFROM. INVESTORS SHOULD BE AWARE THAT THEY MAY BE REQUIRED TO BEAR THE FINANCIAL
RISKS OF THIS INVESTMENT FOR AN INDEFINITE PERIOD OF TIME. THE ISSUER OF THESE SECURITIES MAY REQUIRE AN OPINION OF COUNSEL IN FORM AND SUBSTANCE SATISFACTORY TO THE ISSUER TO THE EFFECT THAT ANY PROPOSED TRANSFER OR RESALE IS IN COMPLIANCE WITH THE
SECURITIES ACT AND ANY APPLICABLE STATE SECURITIES LAWS. 
 THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO CERTAIN
RESTRICTIONS ON PUBLIC RESALE AND TRANSFER, INCLUDING THE RIGHT OF FIRST REFUSAL AND THE REPURCHASE OPTION HELD BY THE ISSUER AND/OR ITS ASSIGNEE(S), AND A MARKET STANDOFF AGREEMENT, AS SET FORTH IN A RESTRICTED STOCK PURCHASE AGREEMENT BETWEEN THE
ISSUER AND THE ORIGINAL HOLDER OF THESE SHARES, A COPY OF WHICH MAY BE OBTAINED AT THE PRINCIPAL OFFICE OF THE ISSUER. SUCH PUBLIC SALE AND TRANSFER RESTRICTIONS INCLUDING THE RIGHT OF FIRST REFUSAL, THE REPURCHASE OPTION AND
THE MARKET STANDOFF ARE BINDING ON TRANSFEREES OF THESE SHARES. 
 Purchaser also agrees that, to ensure compliance with the restrictions imposed by
this Agreement, the Company may issue appropriate “stop-transfer” instructions to its transfer agent, if any, and if the Company transfers its own securities, it may make appropriate notations to the same effect in its own records. The
Company will not be required (a) to transfer on its books any Shares that have been sold or otherwise transferred in violation of any of the provisions of this Agreement or (b) to treat as owner of such Shares, or to accord the right to
vote or pay dividends to any purchaser or other transferee to whom such Shares have been so transferred. 
 8.
TAX CONSEQUENCES. PURCHASER UNDERSTANDS THAT PURCHASER MAY SUFFER ADVERSE TAX CONSEQUENCES AS A RESULT OF PURCHASER’S PURCHASE OR DISPOSITION OF THE SHARES. PURCHASER REPRESENTS (a) THAT PURCHASER
HAS CONSULTED WITH ANY TAX ADVISER THAT PURCHASER DEEMS ADVISABLE IN CONNECTION WITH THE PURCHASE OR DISPOSITION OF THE SHARES AND (b) THAT PURCHASER IS NOT RELYING ON THE COMPANY FOR ANY TAX ADVICE. Purchaser hereby
acknowledges that Purchaser has been informed that, with respect to Unvested Shares, unless an election is filed by Purchaser with the Internal Revenue Service (and, if necessary, the proper state taxing authorities) within 30 days after the
purchase of the Shares electing, pursuant to Section 83(b) of the Internal Revenue Code (and similar state tax provisions, if applicable), to be taxed currently on any difference between the Purchase Price of the Unvested Shares and
their Fair Market Value on the date of purchase, there will be a recognition of taxable income to Purchaser, measured by the excess, if any, of the Fair Market Value of the Unvested Shares, at the time they cease to be Unvested Shares, over the
Purchase Price for such Shares. Purchaser represents that Purchaser has consulted any tax advisers Purchaser deems advisable in connection with Purchaser’s purchase of the Shares and the filing of the election under Section 83(b) and
similar tax provisions. A form of Election under Section 83(b) is attached hereto as Exhibit 1 for reference. BY PROVIDING THE FORM OF ELECTION, NEITHER THE COMPANY NOR ITS LEGAL COUNSEL
IS THEREBY UNDERTAKING TO FILE THE ELECTION FOR PURCHASER, WHICH OBLIGATION TO FILE SHALL REMAIN SOLELY WITH PURCHASER. 

  
 8 

 9. GENERAL PROVISIONS. 

9.1 Successors and Assigns. The Company may assign any of its rights under this Agreement, including its rights to
purchase Shares under the Refusal Right or the Repurchase Option. Neither Purchaser, nor any of Purchaser’s successors and assigns, may assign, whether voluntarily or by operation of law, any of its rights and obligations under this Agreement,
except with the prior written consent of the Company. This Agreement shall be binding upon and inure to the benefit of the successors and assigns of the Company. Subject to the restrictions on transfer herein set forth, this Agreement will be
binding upon Purchaser and Purchaser’s heirs, executors, administrators, legal representatives, successors and assigns. 
 9.2
Notices. Any and all notices required or permitted to be given to a party pursuant to the provisions of this Agreement will be in writing and will be effective and deemed to provide such party sufficient notice under this
Agreement on the earliest of the following: (i) at the time of personal delivery, if delivery is in person; (ii) at the time an electronic confirmation of receipt is received, if delivery is by email; (iii) at the time of transmission
by facsimile, addressed to the other party at its facsimile number specified herein (or hereafter modified by subsequent notice to the parties hereto), with confirmation of receipt made by both telephone and printed confirmation sheet verifying
successful transmission of the facsimile; (iv) one (1) business day after deposit with an express overnight courier for United States deliveries, or two (2) business days after such deposit for deliveries outside of the United States, with
proof of delivery from the courier requested; or (v) three (3) business days after deposit in the United States mail by certified mail (return receipt requested) for United States deliveries. Any notice for delivery outside the United States
will be sent by email, facsimile or by express courier. Any notice not delivered personally or by email will be sent with postage and/or other charges prepaid and properly addressed to Purchaser at the last known address or facsimile number on the
books of the Company, or at such other address or facsimile number as such other party may designate by one of the indicated means of notice herein to the other parties hereto or, in the case of the Company, to it at its principal place of business.
Notices to the Company will be marked “Attention: Chief Financial Officer.” Notices by facsimile shall be machine verified as received. 

9.3 Further Assurances. The parties agree to execute such further documents and instruments and to take such
further actions as may be reasonably necessary to carry out the purposes and intent of this Agreement. 
 9.4 Entire
Agreement. The Plan is incorporated herein by reference. The Plan and this Agreement, together with all Exhibits hereto, constitute the entire agreement and understanding of the parties with respect to the subject matter of this
Agreement, and supersede all prior understandings and agreements, between the parties hereto with respect to the specific subject matter hereof. 

9.5 Severability. If any provision of this Agreement is determined by any court or arbitrator of competent
jurisdiction to be invalid, illegal or unenforceable in any respect, such provision will be enforced to the maximum extent possible given the intent of the parties hereto. If such clause or provision cannot be so enforced, such provision shall be
stricken from this Agreement and the remainder of this Agreement shall be enforced as if such invalid, illegal or unenforceable clause or provision had (to the extent not enforceable) never been contained in this Agreement. Notwithstanding the
forgoing, if the value of this Agreement based upon the substantial benefit of the bargain for any party is materially impaired, which determination as made by the presiding court or arbitrator of competent jurisdiction shall be binding, then both
parties agree to substitute such provision(s) through good faith negotiations. 
 9.6 Execution. This Agreement
may be entered into in two or more counterparts, each of which shall be deemed an original and all of which shall constitute one and the same agreement. This Agreement may be executed and delivered by facsimile and, upon such delivery, the facsimile
signature will be deemed to have the same effect as if the original signature had been delivered to the other party. 
 [The remainder of
this page has intentionally been left blank] 
 [Signature page follows] 

  
 9 

 IN WITNESS WHEREOF, the Company has caused this Restricted Stock Purchase Agreement
to be executed by its duly authorized representative, and Purchaser has executed this Restricted Stock Purchase Agreement, as of the date first set forth above. 
  

			
	PRELUDE THERAPEUTICS INCORPORATED	  	PURCHASER
		
	By:____________________________________	  	____________________________________
		  	
	Address:	  	 Address: __________________________

               __________________________

	Fax No.: (____) __________________	  	Email:    __________________________

 Exhibit 
  

			
	Exhibit 1:	  	Form of Election Pursuant to Section 83(b)

  
 10 

 EXHIBIT 1 

FORM OF SECTION 83(B) ELECTION 

 ELECTION UNDER SECTION 83(b) OF THE 

INTERNAL REVENUE CODE 
 The undersigned
Taxpayer hereby elects, pursuant to Section 83(b) of the Internal Revenue Code of 1986, as amended, to include in gross income for the Taxpayer’s current taxable year the excess, if any, of the fair market value of the property described
below at the time of transfer over the amount paid for such property, as compensation for services. 
  

	1.	 TAXPAYER’S
NAME:                                        
                                         
                                         
                                  

TAXPAYER’S ADDRESS:
                                        
                                         
                                         
                           
  

                        
                                         
                                         
                                         
                                         
       
 SOCIAL SECURITY NUMBER:
                                        
                                         
                                         
                   
 TAXABLE
YEAR:                                        
            Calendar Year _____ 
  

	2.	 The property with respect to which the election is made is described as follows: _______ shares of Common
Stock, par value $0.0001 per share, of Prelude Therapeutics Incorporated, a Delaware corporation (the “Company”), which is Taxpayer’s employer or the corporation for whom the Taxpayer performs services.

  

	3.	 The date on which the shares were transferred was ____________________, _____. 

 

	4.	 The shares are subject to the following restrictions: The Company may repurchase all or a portion of the shares
at the Taxpayer’s original purchase price under certain conditions at the time of Taxpayer’s termination of employment or services. 

  

	5.	 The fair market value of the shares at the time of transfer (without regard to restrictions other than a
nonlapse restriction as defined in § 1.83-3(h) of the Income Tax Regulations) was $____ per share x __________ shares = $__________. 

 

	6.	 The amount paid for such shares was $____ per share x __________ shares = $__________.

  

	7.	 The amount to include in the Taxpayer’s gross income for the Taxpayer’s current taxable year is
$_________. 

 THIS ELECTION MUST BE FILED WITH THE INTERNAL REVENUE SERVICE (“IRS”), AT THE OFFICE
WHERE THE TAXPAYER FILES ANNUAL INCOME TAX RETURNS, WITHIN 30 DAYS AFTER THE DATE OF TRANSFER OF THE PROPERTY, AND MUST ALSO BE FILED WITH THE TAXPAYER’S INCOME TAX RETURNS FOR THE CALENDAR YEAR. A COPY OF THE ELECTION HAS ALSO BEEN
FURNISHED TO THE COMPANY. THE ELECTION CANNOT BE REVOKED WITHOUT THE CONSENT OF THE IRS. 
  

							
	Dated:	 	  
	 	    	  	  

		 		 		  	Taxpayer’s SignatureEX-10.6

 Exhibit 10.6 

EXECUTION VERSION 
 PRELUDE
THERAPEUTICS INCORPORATED 
 550 South College Avenue, Suite 108 

Newark, DE 19713 
 October 5, 2017 

Krishna Vaddi 
 Dear Kris: 

This letter sets forth the compensation and material terms and conditions of your employment with Prelude Therapeutics Incorporated (the
“Company”) as its Chief Executive Officer: 
 Position/Duties: Chief Executive Officer of the Company. You will
devote your full time and attention to the business and affairs of the Company. Notwithstanding the foregoing, you will be permitted to: (1) manage your personal passive investments and (2) remain on the board or equivalent governing body
of each of MPN Research Foundation, Array Biopharma - SAB, Orsenix LLC and Subha Lions Charitable Trust, in each case, so long as they do not interfere with the performance of your duties to the Company or violate any other agreement to which you
are now, or hereafter may become, party to with the Company. 
 Base Salary: $300,000 annual base salary (“Base
Salary”) during the term of your employment with the Company, to be paid in accordance with the Company’s normal payroll cycles. 

Annual Bonus: Eligible to earn an annual bonus (the “Bonus”), with a target annual Bonus equal to 35% of your Base
Salary, for achieving individual and Company performance milestones (the “Performance Milestones”). Your right to receive the Bonus is subject to your continued employment with the Company through the date such Bonus is paid. You
will recommend to the Board of Directors of the Company (the “Board”) the Performance Milestones for each calendar year during the term of your employment, and the Board will consider such recommendations in determining the
Performance Milestones. The determination as to whether the Performance Milestones have been achieved, and the payment of the annual Bonus, will be at the sole discretion of the Board. 

Employee Benefits: 

(a) Vacation: You will be eligible to receive four (4) weeks paid vacation per year during the term of your employment. Any
vacation time not taken by you during any calendar year may not be carried forward into any succeeding calendar year. 
 (b)
Benefit Programs: During the term of your employment, you will be entitled to participate in such life insurance, medical, dental and 401(k) plans and other benefit programs as may be approved from time to time by the Company for the benefit
of the employees of the Company that the Company determines to be of similar rank and status to you, subject to the general eligibility and participation provisions set forth in such plans and applicable law. 

 (c) Reimbursement of Expenses: The Company will reimburse you for all
reasonable business expenses incurred by you during the term of your employment in accordance with Company policy, subject to your submission of relevant invoices or receipts evidencing such business expenses. 

Restricted Stock Grants: You will receive a restricted stock grant under the Company’s 2016 Stock Incentive Plan (as amended, the
“Plan”) (i) on the date of the Initial Closing (as defined in the Purchase Agreement, as defined below) representing five percent (5%) of the fully-diluted capitalization of the Company immediately after giving effect to the Initial
Closing (the “Initial RS Grant”) and (ii) on the date of the Second Closing (as defined in the Purchase Agreement), subject to your continued employment with the Company as of such date, in such amount that, together with the
Initial RS Grant, represents five percent (5%) of the fully-diluted capitalization of the Company immediately after giving effect to the Second Closing (the “Second RS Grant”); provided, however, for purposes of calculating the
number of shares of restricted stock subject to the Second RS Grant, any shares of stock issued from and after the date of the Initial Closing and prior to the date of the Second Closing (other than (1) shares of Series A Preferred Stock of the
Company issued pursuant to Section 1.2(c) of the Purchase Agreement and (2) shares, options or other awards issued under the Plan) shall be disregarded. Each of the Initial RS Grant and the Second RS Grant will vest
over a four (4) year period from the date of the applicable grant, with the first twenty-five percent (25%) of the restricted stock attributable to a particular grant vesting following twelve (12) months of continued employment from the
date of such particular grant, and the remaining restricted stock attributable to such particular grant vesting in equal monthly installments over the following thirty-six (36) months. If your employment
with the Company is terminated without Cause (as defined in the Plan) or you resign for Good Reason (as defined below), there will be six (6) months of accelerated vesting of the then-unvested restricted stock attributable to each of the
Initial RS Grant and the Second RS Grant; provided, however, if your employment with the Company is terminated without Cause or you resign for Good Reason within six (6) months following a Sale of the Company (as defined in the Voting
Agreement, which term is defined in the Purchase Agreement), there will be twelve (12) months of accelerated vesting of the then-unvested restricted stock attributable to each of the Initial RS Grant and the Second RS Grant (and other than
foregoing, there will be no accelerated vesting in any event). The Initial RS Grant will be subject to, and conditioned upon, the execution and delivery of a Restricted Stock Agreement, in the form attached hereto as Exhibit A. The
Second RS Grant, when issued in connection with the Second Closing, will also be subject to, and conditioned upon, the execution and delivery of a Restricted Stock Agreement in form and substance similar to the Restricted Stock Agreement attached
hereto as Exhibit A. 
 Termination of Employment/Severance: Your employment with the Company is “at will”,
which means your employment may be terminated by you or the Company at any time for any reason, with or without Cause, and with or without notice. Upon termination of your employment for any 

 
reason, you will be entitled to receive the following: (i) all accrued but unpaid Base Salary through the date on which your employment ends (the “Termination Date”), (ii)
any unpaid or unreimbursed expenses in accordance with Company policy to the extent incurred prior to the Termination Date and (iii) any accrued but unpaid benefits provided under the Company’s employee benefit plans, subject to and in
accordance with the terms of those plans (collectively, the “Accrued Obligations”). In addition, if your employment is terminated by the Company without Cause or you resign for Good Reason, the Company will, subject to your
execution of a general release (in form and substance satisfactory to the Company) in favor of the Company and its officers, directors, shareholders and their respective affiliates, (y) continue to pay to you (the “Severance
Pay”) your Base Salary (less applicable withholding) for a period of six (6) months following the Termination Date (the “Severance Period”), in the manner and at the same times (subject to any modifications, including
any delay in payment, to the extent necessary to comply with Section 409A of the Code and the Treasury Regulations and other guidance promulgated or issued thereunder) as the Base Salary otherwise would have been payable to you and
(z) continue to provide and pay for, during the Severance Period (or, if you are insured on another health insurance plan prior to the expiration of the Severance Period, until the date you are insured on such other plan), the employer’s
portion of your health insurance coverage in effect on the Termination Date. The Company will have no further liability or obligation after the Termination Date in respect of your employment with the Company and its termination. For the avoidance of
doubt, the termination of your employment upon your death or due to your Disability (as defined in the Plan) does not constitute a without Cause termination. 

Restrictive Covenants: You will be required to, and hereby agree to, execute a Non-Disclosure, Assignment of Inventions and Non-Competition/Non-Solicitation Agreement with the Company. 

Certain Defined Terms: For purposes of this letter, the following terms have the respective meanings set forth below: 

(a) “Good Reason” means (i) a reduction in your Base Salary without your prior written consent; or (ii) the
relocation of your primary work site to a location more than fifty (50) miles from the Company’s current principal office in Newark, Delaware; provided, however, that the termination of your employment with the Company will
not be for “Good Reason” unless you have notified the Company in writing of the existence and details of any act that constitutes Good Reason within sixty (60) days after the occurrence of such act, the Company fails to cure such act
within thirty (30) days following receipt of such notice and you terminate your employment within fifteen (15) days after the expiration of such cure period. 

(b) “Purchase Agreement” means that certain Series A Preferred Stock Purchase Agreement, dated as of the date hereof,
by and among the Company and the purchasers of Series A Preferred Stock of the Company party thereto. 

 This “at-will” employment letter
supersedes all of our prior written and oral communications with you on this subject and can only be modified by a written agreement signed by you and the Company (and subject to such agreement being approved by a majority of the disinterested
directors of the Board). 
 The terms of your employment with the Company and the provisions of this letter will be governed by the laws of
the State of Delaware without regard to principals of conflicts of laws. 
 This letter confirms your acceptance of your employment terms.
We look forward to your continued employment with the Company. 

 
	
	Sincerely,
	
	Prelude Therapeutics Incorporated
	
	/s/ Juan I. Luengo
	Name: Juan I. Luengo
	Title: Vice President

  

	
	Confirmed and Agreed:
	
	/s/ Krishna Vaddi
	Name: Krishna Vaddi
	Date: October 5, 2017

 [Signature Page to Employment Letter]

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