Document:

EX-4.2

 EXHIBIT 4.2 

SECOND AMENDED AND RESTATED INVESTORS’ RIGHTS AGREEMENT 

 TABLE OF CONTENTS 

 

									
	 	  	 	  	 	  	Page	 
			
	 1.
	  	 Definitions.
	  	 	1	 
			
	 2.
	  	 Registration Rights.
	  	 	4	 
		  	 2.1
	  	 Demand Registration.
	  	 	4	 
		  	 2.2
	  	 Company Registration.
	  	 	5	 
		  	 2.3
	  	 Underwriting Requirements.
	  	 	5	 
		  	 2.4
	  	 Obligations of the Company.
	  	 	7	 
		  	 2.5
	  	 Furnish Information.
	  	 	8	 
		  	 2.6
	  	 Expenses of Registration.
	  	 	8	 
		  	 2.7
	  	 Delay of Registration.
	  	 	9	 
		  	 2.8
	  	 Indemnification.
	  	 	9	 
		  	 2.9
	  	 Reports Under Exchange Act.
	  	 	10	 
		  	 2.10
	  	 Limitations on Subsequent Registration Rights.
	  	 	11	 
		  	 2.11
	  	 “Market Stand-off” Agreement.
	  	 	11	 
		  	 2.12
	  	 Restrictions on Transfer.
	  	 	12	 
		  	 2.13
	  	 Termination of Registration Rights.
	  	 	13	 
			
	 3.
	  	 Information and Observer Rights.
	  	 	13	 
		  	 3.1
	  	 Delivery of Financial Statements.
	  	 	13	 
		  	 3.2
	  	 Inspection.
	  	 	14	 
		  	 3.3
	  	 Termination of Information Rights.
	  	 	15	 
		  	 3.4
	  	 Observer Rights.
	  	 	15	 
		  	 3.5
	  	 Confidentiality.
	  	 	16	 
			
	 4.
	  	 Rights to Future Stock Issuances.
	  	 	16	 
		  	 4.1
	  	 Right of First Offer.
	  	 	16	 
		  	 4.2
	  	 Termination.
	  	 	18	 
			
	 5.
	  	 Public Offering Participation Right.
	  	 	18	 
		  	 5.1
	  	 Public Offering.
	  	 	18	 
		  	 5.2
	  	 Private Placement.
	  	 	18	 
		  	 5.3
	  	 Compliance.
	  	 	19	 
		  	 5.4
	  	 This Agreement Not an Offer.
	  	 	19	 
			
	 6.
	  	 Additional Covenants.
	  	 	19	 
		  	 6.1
	  	 Insurance.
	  	 	19	 
		  	 6.2
	  	 Employee Agreements.
	  	 	20	 
		  	 6.3
	  	 Employee Stock.
	  	 	20	 
		  	 6.4
	  	 Matters Requiring Investor Director Approval.
	  	 	20	 
		  	 6.5
	  	 Board Matters.
	  	 	21	 
		  	 6.6
	  	 Successor Indemnification.
	  	 	22	 
		  	 6.7
	  	 Expenses of Counsel.
	  	 	22	 
		  	 6.8
	  	 Indemnification Matters.
	  	 	22	 
		  	 6.9
	  	 Right to Conduct Activities.
	  	 	23	 
		  	 6.11
	  	 FCPA.
	  	 	23	 
		  	 6.12
	  	 Termination of Covenants.
	  	 	23	 

  
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	 7.
	  	 Miscellaneous.
	  	 	24	 
		  	 7.1
	  	 Successors and Assigns.
	  	 	24	 
		  	 7.2
	  	 Governing Law.
	  	 	24	 
		  	 7.3
	  	 Counterparts.
	  	 	24	 
		  	 7.4
	  	 Titles and Subtitles.
	  	 	24	 
		  	 7.5
	  	 Notices.
	  	 	24	 
		  	 7.6
	  	 Amendments and Waivers.
	  	 	25	 
		  	 7.7
	  	 Severability.
	  	 	25	 
		  	 7.8
	  	 Aggregation of Stock.
	  	 	26	 
		  	 7.9
	  	 Additional Investors.
	  	 	26	 
		  	 7.10
	  	 Entire Agreement.
	  	 	26	 
		  	 7.11
	  	 Dispute Resolution.
	  	 	26	 
		  	 7.12
	  	 Delays or Omissions.
	  	 	27	 
		  	 7.13
	  	 Acknowledgment.
	  	 	27	 

  

					
	Schedule A	 	  –  	 	Schedule of Investors

  
 ii 

 SECOND AMENDED AND RESTATED INVESTORS’ RIGHTS AGREEMENT 

THIS SECOND AMENDED AND RESTATED INVESTORS’ RIGHTS AGREEMENT (this “Agreement”), is made as of the 22nd day of October,
2018, by and among Stoke Therapeutics, Inc., a Delaware corporation (the “Company”), and each of the Investors listed on Schedule A hereto, each of which is referred to in this Agreement as an “Investor.”

 RECITALS 

WHEREAS, certain of the Investors hold shares of the Company’s Series A Preferred Stock and Series
A-2 Preferred Stock and/or shares of Common Stock issued upon conversion thereof and possess registration rights, information rights, rights of first offer, and other rights pursuant to an Amended and Restated
Investors’ Rights Agreement dated as of January 5, 2018 between the Company and such Investors (the “Prior Agreement”); and 

WHEREAS, the Investors are holders of at least a majority of the Registrable Securities of the Company (as defined in the Prior
Agreement), and desire to amend and restate the Prior Agreement in its entirety and to accept the rights created pursuant to this Agreement in lieu of the rights granted to them under the Prior Agreement; and 

WHEREAS, certain of the Investors are parties to that certain Series B Preferred Stock Purchase Agreement of even date herewith between
the Company and the Investors (the “Purchase Agreement”), under which certain of the Company’s and such Investors’ obligations are conditioned upon the execution and delivery of this Agreement by the Investors and the
Company; 
 NOW, THEREFORE, the Investors hereby agree that the Prior Agreement shall be amended and restated, and the parties to
this Agreement further agree as follows: 
 1. Definitions. 

For purposes of this Agreement: 

1.1 “Affiliate” means, with respect to any specified Person, any other Person who, directly or indirectly, controls, is
controlled by, or is under common control with such Person, including without limitation any general partner, managing member, officer or director of such Person or any account, fund, venture capital fund or registered investment company now or
hereafter existing that is controlled by one or more general partners, managing members or investment advisers of, or shares the same management company or investment adviser with, such Person. 

1.2 “Common Stock” means shares of the Company’s common stock, par value $0.0001 per share. 

1.3 “Competitor” means a Person engaged, directly or indirectly (including through any partnership, limited liability
company, corporation, joint venture or similar arrangement (whether now existing or formed hereafter)), in the development of oligonucleotide-based therapeutics that selectively increase gene expression to treat disease, but shall not include any
financial investment firm, venture capital fund or collective investment vehicle that, together with its Affiliates, holds less than 40% of the outstanding equity of any Competitor. 

1.4 “Damages” means any loss, damage, claim or liability (joint or several) to which a party hereto may become subject under
the Securities Act, the Exchange Act, or other federal or state law, 

 
insofar as such loss, damage, claim or liability (or any action in respect thereof) arises out of or is based upon: (a) any untrue statement or alleged untrue statement of a material fact
contained in any registration statement of the Company, including any preliminary prospectus or final prospectus contained therein or any amendments or supplements thereto; (b) an omission or alleged omission to state therein a material fact
required to be stated therein, or necessary to make the statements therein not misleading; or (c) any violation or alleged violation by the indemnifying party (or any of its agents or Affiliates) of the Securities Act, the
Exchange Act, any state securities law, or any rule or regulation promulgated under the Securities Act, the Exchange Act, or any state securities law. 

1.5 “Derivative Securities” means any securities or rights convertible into, or exercisable or exchangeable for (in each case,
directly or indirectly), Common Stock, including options and warrants. 
 1.6 “Exchange Act” means the Securities
Exchange Act of 1934, as amended, and the rules and regulations promulgated thereunder. 
 1.7 “Excluded Registration” means
(a) a registration relating to the sale of securities to employees of the Company or a subsidiary pursuant to a stock option, stock purchase, or similar plan; (b) a registration relating to an SEC Rule 145 transaction; (c) a
registration on any form that does not include substantially the same information as would be required to be included in a registration statement covering the sale of the Registrable Securities; or (d) a registration in which the only Common
Stock being registered is Common Stock issuable upon conversion of debt securities that are also being registered. 
 1.8 “FOIA
Party” means a Person that, in the reasonable determination of the Board of Directors, may be subject to, and thereby required to disclose non-public information furnished by or relating to the
Company under, the Freedom of Information Act, 5 U.S.C. 552 (“FOIA”), any state public records access law, any state or other jurisdiction’s laws similar in intent or effect to FOIA, or any other similar statutory or regulatory
requirement. 
 1.9 “Form S-1” means such form under the Securities Act as in effect
on the date hereof or any successor registration form under the Securities Act subsequently adopted by the SEC. 
 1.10 “Form S-3” means such form under the Securities Act as in effect on the date hereof or any registration form under the Securities Act subsequently adopted by the SEC that permits incorporation of substantial
information by reference to other documents filed by the Company with the SEC. 
 1.11 “GAAP” means generally accepted
accounting principles in the United States. 
 1.12 “Holder” means any holder of Registrable Securities who is a party to
this Agreement. 
 1.13 “Immediate Family Member” means a child, stepchild, grandchild, parent, stepparent, grandparent,
spouse, sibling, mother-in-law, father-in-law, son-in-law, daughter-in-law, brother-in-law,
or sister-in-law, including, adoptive relationships, of a natural person referred to herein. 

1.14 “Initiating Holders” means, collectively, Holders who properly initiate a registration request under this Agreement. 

1.15 “IPO” means the Company’s first underwritten public offering of its Common Stock under the Securities Act. 

  
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 1.16 “Major Investor” means any Investor that, individually or together
with such Investor’s Affiliates, holds at least 11,140,819 shares of Registrable Securities then outstanding (as adjusted for any stock split, stock dividend, combination, or other recapitalization or reclassification effected after the date
hereof); provided that in the event that Blackwell Partners LLC – Series A ceases to be an Affiliate of RA Capital Healthcare Fund, L.P., (i) RA Capital Healthcare Fund, L.P. shall remain a Major Investor so long as it holds at least 9,243,538
shares of Registrable Securities then outstanding (as adjusted for any stock split, stock dividend, combination, or other recapitalization or reclassification effected after the date hereof), and (ii) Blackwell Partners LLC – Series A
shall immediately and automatically cease to be a Major Investor. 
 1.17 “New Securities” means, collectively, equity
securities of the Company, whether or not currently authorized, as well as rights, options, or warrants to purchase such equity securities, or securities of any type whatsoever that are, or may become, convertible or exchangeable into or exercisable
for such equity securities. 
 1.18 “Person” means any individual, corporation, partnership, trust, limited liability
company, association or other entity. 
 1.19 “Preferred Stock” means, collectively, all shares of the Series B Preferred
Stock, Series A-2 Preferred Stock and the Series A Preferred Stock. 
 1.20 “Registrable
Securities” means (a) the Common Stock issuable or issued upon conversion of the Preferred Stock; (b) any Common Stock, or any Common Stock issued or issuable (directly or indirectly) upon conversion
and/or exercise of any other securities of the Company, acquired by the Investors after the date hereof; and (c) any Common Stock issued as (or issuable upon the conversion or exercise of any warrant, right, or other
security that is issued as) a dividend or other distribution with respect to, or in exchange for or in replacement of, the shares referenced in clauses (a) and (b) above; excluding in all cases, however, any Registrable
Securities sold by a Person in a transaction in which the applicable rights under this Agreement are not assigned pursuant to Subsection 7.1, and excluding for purposes of Section 2 any shares for which registration
rights have terminated pursuant to Subsection 2.13 of this Agreement. 
 1.21 “Registrable Securities then
outstanding” means the number of shares determined by adding the number of shares of outstanding Common Stock that are Registrable Securities and the number of shares of Common Stock issuable (directly or indirectly) pursuant to then
exercisable and/or convertible securities that are Registrable Securities. 
 1.22 “Restricted Securities” means the
securities of the Company required to be notated with the legend set forth in Subsection 2.12(b) hereof. 
 1.23
“SEC” means the Securities and Exchange Commission. 
 1.24 “SEC Rule 144” means Rule 144 promulgated by
the SEC under the Securities Act. 
 1.25 “SEC Rule 145” means Rule 145 promulgated by the SEC under the Securities Act.

 1.26 “Securities Act” means the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder.

  
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 1.27 “Selling Expenses” means all underwriting discounts, selling
commissions, and stock transfer taxes applicable to the sale of Registrable Securities, and fees and disbursements of counsel for any Holder, except for the fees and disbursements of the Selling Holder Counsel borne and paid by the Company as
provided in Subsection 2.6. 
 1.28 “Series A Preferred Stock” means shares of the Company’s Series A Preferred
Stock, par value $0.0001 per share. 
 1.29 “Series A-2 Preferred Stock” means
shares of the Company’s Series A-2 Preferred Stock, par value $0.0001 per share. 
 1.30
“Series B Preferred Stock” means shares of the Company’s Series B Preferred Stock, par value $0.0001 per share. 
 2.
Registration Rights. 
 The Company covenants and agrees as follows: 

2.1 Demand Registration. 

(a) Form S-1 Demand. If at any time after the earlier of (i) three years after the date of
this Agreement or (ii) 180 days after the effective date of the registration statement for the IPO, the Company receives a request from Holders of a majority of the Registrable Securities then outstanding that the Company file a Form S-1 registration statement having an aggregate offering price, net of Selling Expenses, to the public of not less than $10,000,000, then the Company shall (x) within 10 days after the date such request
is given, give notice thereof (the “Demand Notice”) to all Holders other than the Initiating Holders; and (y) as soon as practicable, and in any event within 60 days after the date such request is given by the Initiating
Holders, file a Form S-1 registration statement under the Securities Act covering all Registrable Securities that the Initiating Holders requested to be registered and any additional Registrable
Securities requested to be included in such registration by any other Holders, as specified by notice given by each such Holder to the Company within 20 days of the date the Demand Notice is given, and in each case, subject to the limitations of
Subsections 2.1(c) and 2.3. 
 (b) Form S-3 Demand. If at any time when
it is eligible to use a Form S-3 registration statement, the Company receives a request from Holders of at least 20% of the Registrable Securities then outstanding that the Company file a Form S-3 registration statement with respect to outstanding Registrable Securities of such Holders having an anticipated aggregate offering price, net of Selling Expenses, of at least $1,000,000, then the Company shall
(i) within 10 days after the date such request is given, give a Demand Notice to all Holders other than the Initiating Holders; and (ii) as soon as practicable, and in any event within 45 days after the date such request is given by the
Initiating Holders, file a Form S-3 registration statement under the Securities Act covering all Registrable Securities requested to be included in such registration by any other Holders, as specified by
notice given by each such Holder to the Company within 20 days of the date the Demand Notice is given, and in each case, subject to the limitations of Subsections 2.1(c) and 2.3. 

(c) Notwithstanding the foregoing obligations, if the Company furnishes to Holders requesting a registration pursuant to this Subsection
2.1 a certificate signed by the Company’s chief executive officer stating that in the good faith judgment of the Company’s Board of Directors it would be materially detrimental to the Company and its stockholders for such registration
statement to either become effective or remain effective for as long as such registration statement otherwise would be required to remain effective, because such action would (i) materially interfere with a significant acquisition, corporate

  
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reorganization, or other similar transaction involving the Company; (ii) require premature disclosure of material information that the Company has a bona fide business purpose for preserving
as confidential; or (iii) render the Company unable to comply with requirements under the Securities Act or Exchange Act, then the Company shall have the right to defer taking action with respect to such filing, and any time periods with
respect to filing or effectiveness thereof shall be tolled correspondingly, for a period of not more than 120 days after the request of the Initiating Holders is given; provided, however, that the Company may not invoke this right more
than once in any 12-month period; and provided, further, that the Company shall not register any securities for its own account or that of any other stockholder during such 120 day period other
than an Excluded Registration. 
 (d) The Company shall not be obligated to effect, or to take any action to effect, any registration
pursuant to Subsection 2.1(a) (i) during the period that is 60 days before the Company’s good faith estimate of the date of filing of, and ending on a date that is 180 days after the effective date of, a
Company-initiated registration; provided that the Company is actively employing in good faith commercially reasonable efforts to cause such registration statement to become effective; (ii) after the Company has effected two registrations
pursuant to Subsection 2.1(a); or (iii) if the Initiating Holders propose to dispose of shares of Registrable Securities that may be immediately registered on Form S-3 pursuant to a request
made pursuant to Subsection 2.1(b). The Company shall not be obligated to effect, or to take any action to effect, any registration pursuant to Subsection 2.1(b) (x) during the period that is 30 days before the Company’s good
faith estimate of the date of filing of, and ending on a date that is 90 days after the effective date of, a Company-initiated registration, provided that the Company is actively employing in good faith commercially reasonable efforts to
cause such registration statement to become effective; or (y) if the Company has effected two registrations pursuant to Subsection 2.1(b) within the 12 month period immediately preceding the date of such request. A registration
shall not be counted as “effected” for purposes of this Subsection 2.1(d) until such time as the applicable registration statement has been declared effective by the SEC, unless the Initiating Holders withdraw their request
for such registration, elect not to pay the registration expenses therefor, and forfeit their right to one demand registration statement pursuant to Subsection 2.6, in which case such withdrawn registration statement shall be counted as
“effected” for purposes of this Subsection 2.1(d). 
 2.2 Company Registration. 

If the Company proposes to register (including, for this purpose, a registration effected by the Company for stockholders other than the
Holders) any of its Common Stock under the Securities Act in connection with the public offering of such securities solely for cash (other than in an Excluded Registration), the Company shall, at such time, promptly give each Holder notice of such
registration. Upon the request of each Holder given within 20 days after such notice is given by the Company, the Company shall, subject to the provisions of Subsection 2.3, cause to be registered all of the Registrable Securities that each
such Holder has requested to be included in such registration. The Company shall have the right to terminate or withdraw any registration initiated by it under this Subsection 2.2 before the effective date of such registration, whether or not
any Holder has elected to include Registrable Securities in such registration. The expenses (other than Selling Expenses) of such withdrawn registration shall be borne by the Company in accordance with Subsection 2.6. 

2.3 Underwriting Requirements. 

(a) If, pursuant to Subsection 2.1, the Initiating Holders intend to distribute the Registrable Securities covered by their
request by means of an underwriting, they shall so advise the Company as a part of their request made pursuant to Subsection 2.1, and the Company shall include such information in the Demand Notice. The underwriter(s) will be selected by the
Initiating Holders, subject only to the reasonable approval of the Company. In such event, the right of any Holder to include such 

  
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Holder’s Registrable Securities in such registration shall be conditioned upon such Holder’s participation in such underwriting and the inclusion of such Holder’s Registrable
Securities in the underwriting to the extent provided herein. All Holders proposing to distribute their securities through such underwriting shall (together with the Company as provided in Subsection 2.4(e)) enter into an underwriting
agreement in customary form with the underwriter(s) selected for such underwriting. Notwithstanding any other provision of this Subsection 2.3, if the managing underwriter(s) advise(s) the Initiating Holders in writing that marketing factors
require a limitation on the number of shares to be underwritten, then the Initiating Holders shall so advise all Holders of Registrable Securities that otherwise would be underwritten pursuant hereto, and the number of Registrable Securities that
may be included in the underwriting shall be allocated among such Holders of Registrable Securities, including the Initiating Holders, in proportion (as nearly as practicable) to the number of Registrable Securities owned by each Holder or in such
other proportion as shall mutually be agreed to by all such selling Holders; provided, however, that the number of Registrable Securities held by the Holders to be included in such underwriting shall not be reduced unless all other
securities are first entirely excluded from the underwriting. To facilitate the allocation of shares in accordance with the above provisions, the Company or the underwriters may round the number of shares allocated to any Holder to the nearest 100
shares. 
 (b) In connection with any offering involving an underwriting of shares of the Company’s capital stock pursuant to
Subsection 2.2, the Company shall not be required to include any of the Holders’ Registrable Securities in such underwriting unless the Holders accept the terms of the underwriting as agreed upon between the Company and its underwriters,
and then only in such quantity as the underwriters in their sole discretion determine will not jeopardize the success of the offering by the Company. If the total number of securities, including Registrable Securities, requested by stockholders to
be included in such offering exceeds the number of securities to be sold (other than by the Company) that the underwriters in their reasonable discretion determine is compatible with the success of the offering, then the Company shall be required to
include in the offering only that number of such securities, including Registrable Securities, which the underwriters and the Company in their sole discretion determine will not jeopardize the success of the offering. If the underwriters determine
that less than all of the Registrable Securities requested to be registered can be included in such offering, then the Registrable Securities that are included in such offering shall be allocated among the selling Holders in proportion (as nearly as
practicable to) the number of Registrable Securities owned by each selling Holder or in such other proportions as shall mutually be agreed to by all such selling Holders. To facilitate the allocation of shares in accordance with the above
provisions, the Company or the underwriters may round the number of shares allocated to any Holder to the nearest 100 shares. Notwithstanding the foregoing, in no event shall (i) the number of Registrable Securities included in the offering be
reduced unless all other securities (other than securities to be sold by the Company) are first entirely excluded from the offering, or (ii) the number of Registrable Securities included in the offering be reduced below 25% of the total number
of securities included in such offering, unless such offering is the IPO, in which case the selling Holders may be excluded further if the underwriters make the determination described above and no other stockholder’s securities are included in
such offering. For purposes of the provision in this Subsection 2.3(a) concerning apportionment, for any selling Holder that is a partnership, limited liability company, or corporation, the partners, members, retired partners, retired
members, stockholders, and Affiliates of such Holder, or the estates and Immediate Family Members of any such partners, retired partners, members, and retired members and any trusts for the benefit of any of the foregoing Persons, shall be deemed to
be a single “selling Holder,” and any pro rata reduction with respect to such “selling Holder” shall be based upon the aggregate number of Registrable Securities owned by all Persons included in such “selling Holder,”
as defined in this sentence. 
 (c) For purposes of Subsection 2.1, a registration shall not be counted as “effected” if,
as a result of an exercise of the underwriter’s cutback provisions in Subsection 2.3(a), fewer 

  
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than 50% of the total number of Registrable Securities that Holders have requested to be included in such registration statement are actually included. 

2.4 Obligations of the Company. 

Whenever required under this Section 2 to effect the registration of any Registrable Securities, the Company shall,
as expeditiously as reasonably possible: 
 (a) prepare and file with the SEC a registration statement with respect to such Registrable
Securities and use its commercially reasonable efforts to cause such registration statement to become effective and, upon the request of the Holders of a majority of the Registrable Securities registered thereunder, keep such registration statement
effective for a period of up to 120 days or, if earlier, until the distribution contemplated in the registration statement has been completed; provided, however, that (i) such 120 day period shall be extended for a period of time
equal to the period the Holder refrains, at the request of an underwriter of Common Stock (or other securities) of the Company, from selling any securities included in such registration, and (ii) in the case of any registration of Registrable
Securities on Form S-3 that are intended to be offered on a continuous or delayed basis, subject to compliance with applicable SEC rules, such 120 day period shall be extended for up to 60 days, if necessary,
to keep the registration statement effective until all such Registrable Securities are sold; 
 (b) prepare and file with the SEC such
amendments and supplements to such registration statement, and the prospectus used in connection with such registration statement, as may be necessary to comply with the Securities Act in order to enable the disposition of all securities covered by
such registration statement; 
 (c) furnish to the selling Holders such numbers of copies of a prospectus, including a preliminary
prospectus, as required by the Securities Act, and such other documents as the Holders may reasonably request in order to facilitate their disposition of their Registrable Securities; 

(d) use its commercially reasonable efforts to register and qualify the securities covered by such registration statement under such other
securities or blue-sky laws of such jurisdictions as shall be reasonably requested by the selling Holders; provided that the Company shall not be required to qualify to do business or to file a general
consent to service of process in any such states or jurisdictions, unless the Company is already subject to service in such jurisdiction and except as may be required by the Securities Act; 

(e) in the event of any underwritten public offering, enter into and perform its obligations under an underwriting agreement, in usual and
customary form, with the underwriter(s) of such offering; 
 (f) use its commercially reasonable efforts to cause all such Registrable
Securities covered by such registration statement to be listed on a national securities exchange or trading system and each securities exchange and trading system (if any) on which similar securities issued by the Company are then listed; 

(g) provide a transfer agent and registrar for all Registrable Securities registered pursuant to this Agreement and provide a CUSIP number for
all such Registrable Securities, in each case not later than the effective date of such registration; 
 (h) promptly make available for
inspection by the selling Holders, any managing underwriter(s) participating in any disposition pursuant to such registration statement, and any 

  
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attorney or accountant or other agent retained by any such underwriter or selected by the selling Holders, all financial and other records, pertinent corporate documents, and properties of the
Company, and cause the Company’s officers, directors, employees, and independent accountants to supply all information reasonably requested by any such seller, underwriter, attorney, accountant, or agent, in each case, as necessary or advisable
to verify the accuracy of the information in such registration statement and to conduct appropriate due diligence in connection therewith; 

(i) notify each selling Holder, promptly after the Company receives notice thereof, of the time when such registration statement has been
declared effective or a supplement to any prospectus forming a part of such registration statement has been filed; and 
 (j) after such
registration statement becomes effective, notify each selling Holder of any request by the SEC that the Company amend or supplement such registration statement or prospectus. 

In addition, the Company shall ensure that, at all times after any registration statement covering a public offering of securities of the
Company under the Securities Act shall have become effective, its insider trading policy shall provide that the Company’s directors may implement a trading program under Rule 10b5-1 of the Exchange Act.

 2.5 Furnish Information. 

It shall be a condition precedent to the obligations of the Company to take any action pursuant to this Section 2
with respect to the Registrable Securities of any selling Holder that such Holder shall furnish to the Company such information regarding itself, the Registrable Securities held by it, and the intended method of disposition of such securities as is
reasonably required to effect the registration of such Holder’s Registrable Securities. 
 2.6 Expenses of Registration. 

All expenses (other than Selling Expenses) incurred in connection with registrations, filings, or qualifications pursuant to
Section 2, including all registration, filing, and qualification fees; printers’ and accounting fees; fees and disbursements of counsel for the Company; and the reasonable fees and disbursements of one counsel for the
selling Holders (“Selling Holder Counsel”), shall be borne and paid by the Company; provided, however, that the Company shall not be required to pay for any expenses of any registration proceeding begun pursuant
to Subsection 2.1 if the registration request is subsequently withdrawn at the request of the Holders of a majority of the Registrable Securities to be registered (in which case all selling Holders shall bear such expenses pro rata based upon
the number of Registrable Securities that were to be included in the withdrawn registration), unless the Holders of a majority of the Registrable Securities agree to forfeit their right to one registration pursuant to Subsections
2.1(a) or 2.1(b), as the case may be; provided further that if, at the time of such withdrawal, the Holders shall have learned of a material adverse change in the condition, business, or prospects of the Company from
that known to the Holders at the time of their request and have withdrawn the request with reasonable promptness after learning of such information then the Holders shall not be required to pay any of such expenses and shall not forfeit their right
to one registration pursuant to Subsections 2.1(a) or 2.1(b). All Selling Expenses relating to Registrable Securities registered pursuant to this Section 2 shall be borne and paid by the Holders pro rata on
the basis of the number of Registrable Securities registered on their behalf. 

  
 8 

 2.7 Delay of Registration. 

No Holder shall have any right to obtain or seek an injunction restraining or otherwise delaying any registration pursuant to this Agreement as
the result of any controversy that might arise with respect to the interpretation or implementation of this Section 2. 
 2.8
Indemnification. 
 If any Registrable Securities are included in a registration statement under this
Section 2: 
 (a) To the extent permitted by law, the Company will indemnify and hold harmless each selling
Holder, and the partners, members, officers, directors, and stockholders of each such Holder; legal counsel and accountants for each such Holder; any underwriter (as defined in the Securities Act) for each such Holder; and each Person, if any, who
controls such Holder or underwriter within the meaning of the Securities Act or the Exchange Act, against any Damages, and the Company will pay to each such Holder, underwriter, controlling Person, or other aforementioned Person any legal or other
expenses reasonably incurred thereby in connection with investigating or defending any claim or proceeding from which Damages may result, as such expenses are incurred; provided, however, that the indemnity agreement contained in this
Subsection 2.8(a) shall not apply to amounts paid in settlement of any such claim or proceeding if such settlement is effected without the consent of the Company, which consent shall not be unreasonably withheld, nor shall the Company
be liable for any Damages to the extent that they arise out of or are based upon actions or omissions made in reliance upon and in conformity with written information furnished by or on behalf of any such Holder, underwriter, controlling Person, or
other aforementioned Person expressly for use in connection with such registration. 
 (b) To the extent permitted by law, each selling
Holder, severally and not jointly, will indemnify and hold harmless the Company, and each of its directors, each of its officers who has signed the registration statement, each Person (if any), who controls the Company within the meaning of the
Securities Act, legal counsel and accountants for the Company, any underwriter (as defined in the Securities Act), any other Holder selling securities in such registration statement, and any controlling Person of any such underwriter or other
Holder, against any Damages, in each case only to the extent that such Damages arise out of or are based upon actions or omissions made in reliance upon and in conformity with written information furnished by or on behalf of such selling Holder
expressly for use in connection with such registration; and each such selling Holder will pay to the Company and each other aforementioned Person any legal or other expenses reasonably incurred thereby in connection with investigating or defending
any claim or proceeding from which Damages may result, as such expenses are incurred; provided, however, that the indemnity agreement contained in this Subsection 2.8(b) shall not apply to amounts paid in settlement of
any such claim or proceeding if such settlement is effected without the consent of the Holder, which consent shall not be unreasonably withheld; and provided further that in no event shall the aggregate amounts payable by any Holder by
way of indemnity or contribution under Subsections 2.8(b) and 2.8(c) exceed the proceeds from the offering received by such Holder (net of any Selling Expenses paid by such Holder), except in the case of fraud or willful misconduct by
such Holder. 
 (c) Promptly after receipt by an indemnified party under this Subsection 2.8 of notice of the commencement of
any action (including any governmental action) for which a party may be entitled to indemnification hereunder, such indemnified party will, if a claim in respect thereof is to be made against any indemnifying party under this Subsection 2.8,
give the indemnifying party notice of the commencement thereof. The indemnifying party shall have the right to participate in such action and, to the extent the indemnifying party so desires, participate jointly with any other indemnifying party to
which notice has been given, and to assume the defense thereof with counsel mutually satisfactory to the parties; provided, however, that an indemnified party (together with all other indemnified parties that may be

  
 9 

 
represented without conflict by one counsel) shall have the right to retain one separate counsel, with the fees and expenses to be paid by the indemnifying party, if representation of such
indemnified party by the counsel retained by the indemnifying party would be inappropriate due to actual or potential differing interests between such indemnified party and any other party represented by such counsel in such action 

(d) To provide for just and equitable contribution to joint liability under the Securities Act in any case in which either: (i) any party
otherwise entitled to indemnification hereunder makes a claim for indemnification pursuant to this Subsection 2.8 but it is judicially determined (by the entry of a final judgment or decree by a court of competent jurisdiction and the
expiration of time to appeal or the denial of the last right of appeal) that such indemnification may not be enforced in such case, notwithstanding the fact that this Subsection 2.8 provides for indemnification in such case, or
(ii) contribution under the Securities Act may be required on the part of any party hereto for which indemnification is provided under this Subsection 2.8, then, and in each such case, such parties will contribute to the aggregate
losses, claims, damages, liabilities, or expenses to which they may be subject (after contribution from others) in such proportion as is appropriate to reflect the relative fault of each of the indemnifying party and the indemnified party in
connection with the statements, omissions, or other actions that resulted in such loss, claim, damage, liability, or expense, as well as to reflect any other relevant equitable considerations. The relative fault of the indemnifying party and of the
indemnified party shall be determined by reference to, among other things, whether the untrue or allegedly untrue statement of a material fact, or the omission or alleged omission of a material fact, relates to information supplied by the
indemnifying party or by the indemnified party and the parties’ relative intent, knowledge, access to information, and opportunity to correct or prevent such statement or omission; provided, however, that, in any such case
(x) no Holder will be required to contribute any amount in excess of the public offering price of all such Registrable Securities offered and sold by such Holder pursuant to such registration statement, and (y) no Person guilty of
fraudulent misrepresentation (within the meaning of Section 11(f) of the Securities Act) will be entitled to contribution from any Person who was not guilty of such fraudulent misrepresentation; and provided further that in no
event shall a Holder’s liability pursuant to this Subsection 2.8(c), when combined with the amounts paid or payable by such Holder pursuant to Subsection 2.8(b), exceed the proceeds from the offering received by such Holder (net
of any Selling Expenses paid by such Holder), except in the case of willful misconduct or fraud by such Holder. 
 (e) Notwithstanding the
foregoing, to the extent that the provisions on indemnification and contribution contained in the underwriting agreement entered into in connection with the underwritten public offering are in conflict with the foregoing provisions, the provisions
in the underwriting agreement shall control. 
 (f) Unless otherwise superseded by an underwriting agreement entered into in connection with
the underwritten public offering, the obligations of the Company and Holders under this Subsection 2.8 shall survive the completion of any offering of Registrable Securities in a registration under this Section 2,
and otherwise shall survive the termination of this Agreement. 
 2.9 Reports Under Exchange Act. 

With a view to making available to the Holders the benefits of SEC Rule 144 and any other rule or regulation of the SEC that may at any time
permit a Holder to sell securities of the Company to the public without registration or pursuant to a registration on Form S-3, the Company shall: 

(a) make and keep available adequate current public information, as those terms are understood and defined in SEC Rule 144, at all times after
the effective date of the registration statement filed by the Company for the IPO; 

  
 10 

 (b) use commercially reasonable efforts to file with the SEC in a timely manner all reports
and other documents required of the Company under the Securities Act and the Exchange Act (at any time after the Company has become subject to such reporting requirements); and 

(c) furnish to any Holder, so long as the Holder owns any Registrable Securities, forthwith upon request (i) to the extent accurate, a
written statement by the Company that it has complied with the reporting requirements of SEC Rule 144 (at any time after 90 days after the effective date of the registration statement filed by the Company for the IPO), the Securities Act, and the
Exchange Act (at any time after the Company has become subject to such reporting requirements), or that it qualifies as a registrant whose securities may be resold pursuant to Form S-3 (at any time after the
Company so qualifies); (ii) a copy of the most recent annual or quarterly report of the Company and such other reports and documents so filed by the Company; and (iii) such other information as may be reasonably requested in availing any Holder
of any rule or regulation of the SEC that permits the selling of any such securities without registration (at any time after the Company has become subject to the reporting requirements under the Exchange Act) or pursuant to Form S-3 (at any time after the Company so qualifies to use such form). 
 2.10 Limitations on Subsequent
Registration Rights.  
 From and after the date of this Agreement, the Company shall not, without the prior written consent of
the holders of (a) a majority of the then-outstanding shares of Series A Preferred Stock and Series A-2 Preferred Stock, voting as a single class and (b) a majority of the outstanding Series B
Preferred Stock voting together as a single class (clauses (a) and (b) collectively, the “Requisite Holders”), enter into any agreement with any holder or prospective holder of any securities of the Company that (i) would
provide to such holder the right to include securities in any registration on other than either a pro rata basis with respect to the Registrable Securities or on a subordinate basis after all Holders have had the opportunity to include in the
registration and offering all shares of Registrable Securities that they wish to so include; or (ii) allow such holder or prospective holder to initiate a demand for registration of any securities held by such holder or prospective holder;
provided that this limitation shall not apply to any additional Investor who becomes a party to this Agreement in accordance with Subsection 7.9. 

2.11 “Market Stand-off” Agreement. 

Each Holder hereby agrees that it will not, without the prior written consent of the managing underwriter, during the period commencing on the
date of the final prospectus relating to an IPO and ending on the date specified by the Company and the managing underwriter (such period not to exceed 180 days, or such other period as may be requested by the Company or an underwriter to
accommodate regulatory restrictions on (1) the publication or other distribution of research reports, and (2) analyst recommendations and opinions, including, but not limited to, the restrictions contained in FINRA Rule 2711(f)(4) or NYSE
Rule 472(f)(4), or any successor provisions or amendments thereto), (i) lend; offer; pledge; sell; contract to sell; sell any option or contract to purchase; purchase any option or contract to sell; grant any option, right, or warrant to purchase;
or otherwise transfer or dispose of, directly or indirectly, any shares of Common Stock or any securities convertible into or exercisable or exchangeable (directly or indirectly) for Common Stock (whether such shares or any such securities are then
owned by the Holder or are thereafter acquired) held immediately before the effective date of the registration statement for such offering or (ii) enter into any swap or other arrangement that transfers to another, in whole or in
part, any of the economic consequences of ownership of such securities, whether any such transaction described in clause (i) or (ii) above is to be settled by delivery of Common Stock or other securities, in cash, or
otherwise. The foregoing provisions of this Subsection 2.11 shall apply only to the IPO, shall not apply to the sale of any shares to an underwriter pursuant to an underwriting agreement, or the transfer of any shares to any trust for
the direct or indirect benefit of the Holder or the immediate family of the Holder, provided that the trustee of the trust agrees to be bound in writing by the restrictions set forth herein, and provided, further,

  
 11 

 
that any such transfer shall not involve a disposition for value, and shall be applicable to the Holders only if all officers and directors are subject to the same restrictions and the Company
uses commercially reasonable efforts to obtain a similar agreement from all stockholders individually owning more than one percent of the Company’s outstanding Common Stock (after giving effect to conversion into Common Stock of all outstanding
Preferred Stock). The underwriters in connection with such registration are intended third-party beneficiaries of this Subsection 2.11 and shall have the right, power and authority to enforce the provisions hereof as though they were a party
hereto. Each Holder further agrees to execute such agreements as may be reasonably requested by the underwriters in connection with such registration that are consistent with this Subsection 2.11 or that are necessary to give further effect
thereto. Any discretionary waiver or termination of the restrictions of any or all of such agreements by the Company or the underwriters shall apply pro rata to all Company stockholders that are subject to such agreements, based on the number of
shares subject to such agreements. 
 2.12 Restrictions on Transfer. 

(a) The Preferred Stock and the Registrable Securities shall not be sold, pledged, or otherwise transferred, and the Company shall not
recognize and shall issue stop-transfer instructions to its transfer agent with respect to any such sale, pledge, or transfer, except upon the conditions specified in this Agreement, which conditions are intended to ensure compliance with the
provisions of the Securities Act. A transferring Holder will cause any proposed purchaser, pledgee, or transferee of the Preferred Stock and the Registrable Securities held by such Holder to agree to take and hold such securities subject to the
provisions and upon the conditions specified in this Agreement. 
 (b) Each certificate, instrument, or book entry representing (i) the
Preferred Stock, (ii) the Registrable Securities, and (iii) any other securities issued in respect of the securities referenced in clauses (i) and (ii), upon any stock split, stock dividend,
recapitalization, merger, consolidation, or similar event, shall (unless otherwise permitted by the provisions of Subsection 2.12(c)) be notated with a legend substantially in the following form: 

THE SECURITIES REPRESENTED HEREBY HAVE BEEN ACQUIRED FOR INVESTMENT AND HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. SUCH SHARES
MAY NOT BE SOLD, PLEDGED, OR TRANSFERRED IN THE ABSENCE OF SUCH REGISTRATION OR A VALID EXEMPTION FROM THE REGISTRATION AND PROSPECTUS DELIVERY REQUIREMENTS OF SAID ACT. 

THE SECURITIES REPRESENTED HEREBY MAY BE TRANSFERRED ONLY IN ACCORDANCE WITH THE TERMS OF AN AGREEMENT BETWEEN THE COMPANY AND THE STOCKHOLDER,
A COPY OF WHICH IS ON FILE WITH THE SECRETARY OF THE COMPANY. 
 The Holders consent to the Company making a notation in its records and
giving instructions to any transfer agent of the Restricted Securities in order to implement the restrictions on transfer set forth in this Subsection 2.12. 

(c) The holder of such Restricted Securities, by acceptance of ownership thereof, agrees to comply in all respects with the provisions of this
Section 2. Before any proposed sale, pledge, or transfer of any Restricted Securities, unless there is in effect a registration statement under the Securities Act covering the proposed transaction, the Holder thereof shall
give notice to the Company of such Holder’s intention to effect such sale, pledge, or transfer. Each such notice shall describe the manner and circumstances of the proposed sale, pledge, or transfer in sufficient detail and, if reasonably
requested 

  
 12 

 
by the Company, shall be accompanied at such Holder’s expense by either (i) a written opinion of legal counsel who shall, and whose legal opinion shall, be reasonably satisfactory to
the Company, addressed to the Company, to the effect that the proposed transaction may be effected without registration under the Securities Act; (ii) a “no action” letter from the SEC to the effect that the proposed sale, pledge, or
transfer of such Restricted Securities without registration will not result in a recommendation by the staff of the SEC that action be taken with respect thereto; or (iii) any other evidence reasonably satisfactory to counsel to the Company to
the effect that the proposed sale, pledge, or transfer of the Restricted Securities may be effected without registration under the Securities Act, whereupon the Holder of such Restricted Securities shall be entitled to sell, pledge, or transfer such
Restricted Securities in accordance with the terms of the notice given by the Holder to the Company. The Company will not require such a legal opinion or “no action” letter (x) in any transaction in compliance with SEC Rule 144; or
(y) in any transaction in which such Holder distributes Restricted Securities to an Affiliate of such Holder; provided that each transferee agrees in writing to be subject to the terms of this Subsection 2.12. Each certificate,
instrument, or book entry representing the Restricted Securities transferred as above provided shall be notated with, except if such transfer is made pursuant to SEC Rule 144, the appropriate restrictive legend set forth in Subsection
2.12(b), except that such certificate instrument, or book entry shall not be notated with such restrictive legend if, in the opinion of counsel for such Holder and the Company, such legend is not required in order to establish compliance with
any provisions of the Securities Act. 
 2.13 Termination of Registration Rights. 

The right of any Holder to request registration or inclusion of Registrable Securities in any registration pursuant to Subsections 2.1
or 2.2 shall terminate upon the earliest to occur of: 
 (a) the fifth anniversary of the IPO; and 

(b) with respect to each Holder, such time following the IPO as all Registrable Securities of such holder may be sold within a three month
period pursuant to Rule 144. 
 3. Information and Observer Rights. 

3.1 Delivery of Financial Statements. 

The Company shall deliver to each Major Investor: 

(a) as soon as practicable, but in any event within 45 days after the end of each fiscal year of the Company (i) an unaudited balance
sheet as of the end of such year, (ii) unaudited statements of income and of cash flows for such year, and a comparison between (x) the actual amounts as of and for such fiscal year and (y) the comparable amounts for the prior
year and as included in the Budget (as defined below) for such year, with an explanation of any material differences between such amounts and a schedule as to the sources and applications of funds for such year, and (iii) a statement of
stockholders’ equity as of the end of such year, all prepared in accordance with GAAP (except that such financial statements may (1) be subject to normal year-end audit adjustments; and (2) not
contain all notes thereto that may be required in accordance with GAAP); 
 (b) as soon as practicable, but in any event within 120 days
after the end of each fiscal year of the Company (i) a balance sheet as of the end of such year, (ii) statements of income and of cash flows for such year, and a comparison between (x) the actual amounts as of and for such fiscal year
and (y) the comparable amounts for the prior year and as included in the Budget (as defined below) for such year, with an explanation of any material differences between such amounts and a schedule as to the sources and applications of funds
for such year, and (iii) a statement of stockholders’ equity as of the end of such 

  
 13 

 
year, all such financial statements audited and certified by independent public accountants of nationally recognized standing selected by the Company; 

(c) as soon as practicable, but in any event within 45 days after the end of each of the first three quarters of each fiscal year of the
Company, (i) unaudited statements of income and cash flows for such fiscal quarter, and a comparison between (x) the actual amounts as of and for such fiscal quarter and (y) the comparable amounts for the prior quarter and as included
in the Budget (as defined in below) for such quarter, with an explanation of any material differences between such amounts and a schedule as to the sources and applications of funds for such quarter, and (ii) an unaudited balance sheet
and a statement of stockholders’ equity as of the end of such fiscal quarter, all prepared in accordance with GAAP (except that such financial statements may (1) be subject to normal year-end audit
adjustments; and (2) not contain all notes thereto that may be required in accordance with GAAP); 
 (d) as soon as practicable, but in
any event within 30 days of the end of each month, (i) an unaudited income statement and statement of cash flows for such month, and a comparison between (x) the actual amounts as of and for such month and (y) the comparable amounts
for the prior month and as included in the Budget (as defined below) for such month, with an explanation of any material differences between such amounts and a schedule as to the sources and applications of funds for such month, and (ii) an
unaudited balance sheet and statement of stockholders’ equity as of the end of such month, all prepared in accordance with GAAP (except that such financial statements may (1) be subject to normal
year-end audit adjustments and (2) not contain all notes thereto that may be required in accordance with GAAP); and 

(e) as soon as practicable, but in any event 30 days before the end of each fiscal year, a budget and business plan for the next fiscal year
(collectively, the “Budget”), approved by the Board of Directors and prepared on a monthly basis, including balance sheets, income statements, and statements of cash flow for such months and, promptly after prepared, any other
budgets or revised budgets prepared by the Company. 
 If, for any period, the Company has any subsidiary whose accounts are consolidated
with those of the Company, then in respect of such period the financial statements delivered pursuant to the foregoing sections shall be the consolidated and consolidating financial statements of the Company and all such consolidated
subsidiaries.
 Notwithstanding anything else in this Subsection 3.1 to the contrary, the Company may cease providing the information
set forth in this Subsection 3.1 during the period starting with the date 60 days before the Company’s good-faith estimate of the date of filing of a registration statement if it reasonably concludes it must do so to comply with the SEC
rules applicable to such registration statement and related offering; provided that the Company’s covenants under this Subsection 3.1 shall be reinstated at such time as the Company is no longer actively employing its commercially
reasonable efforts to cause such registration statement to become effective. 
 3.2 Inspection. 

The Company shall permit each Major Investor, at such Major Investor’s expense, to visit and inspect the Company’s properties;
examine its books of account and records; and discuss the Company’s affairs, finances, and accounts with its officers, during normal business hours of the Company as may be reasonably requested by the Major Investor; provided,
however, that the Company shall not be obligated pursuant to this Subsection 3.2 to provide access to any information that it reasonably and in good faith considers to be a trade secret or confidential information (unless covered by an
enforceable confidentiality agreement, in form acceptable to the Company (it being understood that the provisions of 

  
 14 

 
Subsection 3.5 hereof are acceptable to the Company for this purpose) or the disclosure of which would adversely affect the attorney-client privilege between the Company and its counsel.

 3.3 Termination of Information Rights. 

The covenants set forth in Subsection 3.1 and Subsection 3.2 shall terminate and be of no further force or effect
(a) immediately before the consummation of the IPO, (b) when the Company first becomes subject to the periodic reporting requirements of Section 12(g) or 15(d) of the Exchange Act, or (c) upon a Deemed Liquidation Event, as such
term is defined in the Company’s certificate of incorporation, whichever event occurs first. 
 3.4 Observer Rights. 

(a) As long as RTW Master Fund, Ltd., RTW Innovation Master Fund, Ltd. or any of their respective Affiliates (collectively,
“RTW”) hold any shares of Preferred Stock (or shares of Common Stock issued upon conversion thereof), the Company shall invite a representative of RTW to attend all meetings of the Board of Directors in a nonvoting observer capacity
and, in this respect, shall give such representative copies of all notices, minutes, consents and other materials that it provides to its directors; provided, however, that such representative shall agree to hold in confidence and
trust with respect to all information so provided; and provided further, that the Company reserves the right to withhold any information and to exclude such representative from any meeting or portion thereof if such information or
attendance at such meeting could adversely affect the attorney-client privilege between the Company and its counsel or result in disclosure of trade secrets or a direct conflict of interest, or if such Investor or its representative is a Competitor
of the Company. RTW shall be responsible to the Company for any disclosure or misuse of any information provided under this Subsection 3.4(a) that results from its representative’s failure to comply with this Subsection 3.4(a).

 (b) As long as Apple Tree Partners IV, L.P. or any of its Affiliates (“ATP”) holds any shares of Preferred Stock (or
shares of Common Stock issued upon conversion thereof) the Company shall invite a representative of ATP to attend all meetings of the Board of Directors in a nonvoting observer capacity and, in this respect, shall give such representative copies of
all notices, minutes, consents and other materials that it provides to its directors; provided, however, that such representative shall agree to hold in confidence and trust with respect to all information so provided; and
provided further, that the Company reserves the right to withhold any information and to exclude such representative from any meeting or portion thereof if such information or attendance at such meeting could adversely affect the
attorney-client privilege between the Company and its counsel or result in disclosure of trade secrets or a conflict of interest, or if such Investor or its representative is a Competitor of the Company. ATP shall be responsible to the Company for
any disclosure or misuse of any information provided under this Subsection 3.4(b) that results from its representative’s failure to comply with this Subsection 3.4(b). 

(c) As long as Cormorant Private Healthcare Fund I, LP or any of its Affiliates (“Cormorant”) holds any shares of Preferred
Stock (or shares of Common Stock issued upon conversion thereof) the Company shall invite a representative of Cormorant to attend all meetings of the Board of Directors in a nonvoting observer capacity and, in this respect, shall give such
representative copies of all notices, minutes, consents and other materials that it provides to its directors; provided, however, that such representative shall agree to hold in confidence and trust with respect to all information so
provided; and provided further, that the Company reserves the right to withhold any information and to exclude such representative from any meeting or portion thereof if such information or attendance at such meeting could adversely
affect the attorney-client privilege between the Company and its counsel or result in disclosure of trade secrets or a conflict of interest, or if such Investor or its representative is a Competitor of the Company. Cormorant shall be responsible to
the Company for any disclosure or misuse of any information 

  
 15 

 
provided under this Section 3.4(c) that results from its representative’s failure to comply with this Subsection 3.4(c). 

(d) As long as RA Capital Healthcare Fund, L.P. or any of its Affiliates (“RA Capital”) holds any shares of Preferred Stock
(or shares of Common Stock issued upon conversion thereof) the Company shall invite a representative of RA Capital to attend all meetings of the Board of Directors in a nonvoting observer capacity and, in this respect, shall give such representative
copies of all notices, minutes, consents and other materials that it provides to its directors; provided, however, that such representative shall agree to hold in confidence and trust with respect to all information so provided; and
provided further, that the Company reserves the right to withhold any information and to exclude such representative from any meeting or portion thereof if such information or attendance at such meeting could adversely affect the
attorney-client privilege between the Company and its counsel or result in disclosure of trade secrets or a conflict of interest, or if such Investor or its representative is a Competitor of the Company. RA Capital shall be responsible to the
Company for any disclosure or misuse of any information provided under this Section 3.4(d) that results from its representative’s failure to comply with this Subsection 3.4(d). 

3.5 Confidentiality. 

Each Investor agrees that such Investor will keep confidential and will not disclose, divulge, or use for any purpose (other than to monitor
its investment in the Company) any confidential information obtained from the Company pursuant to the terms of this Agreement (including notice of the Company’s intention to file a registration statement), unless such confidential information
(a) is known or becomes known to the public in general (other than as a result of a breach of this Subsection 3.5 by such Investor), (b) is or has been independently developed or conceived by the Investor without use of the
Company’s confidential information, or (c) is or has been made known or disclosed to the Investor by a third party without a breach of any obligation of confidentiality such third party may have to the Company; provided,
however, that an Investor may disclose confidential information (i) to its attorneys, accountants, consultants, and other professionals to the extent necessary to obtain their services in connection with monitoring its investment in the
Company; (ii) to any prospective purchaser of any Registrable Securities from such Investor, if such prospective purchaser agrees to be bound by the provisions of this Subsection 3.5; (iii) to any existing or prospective
Affiliate, partner, member, stockholder, or wholly owned subsidiary of such Investor in the ordinary course of business, provided that such Investor informs such Person that such information is confidential and directs such Person to maintain
the confidentiality of such information; or (iv) as may otherwise be required by law, provided that the Investor promptly notifies the Company of such disclosure and takes reasonable steps to minimize the extent of any such required
disclosure. 
 4. Rights to Future Stock Issuances. 

4.1 Right of First Offer. 

Subject to the terms and conditions of this Subsection 4.1 and applicable securities laws, if the Company proposes to offer or sell any
New Securities, the Company shall first offer such New Securities to each Major Investor. A Major Investor shall be entitled to apportion the right of first offer hereby granted to it in such proportions as it deems appropriate, among
(a) itself, (b) its Affiliates and (c) its beneficial interest holders, such as limited partners, members or any other Person having “beneficial ownership,” as such term is defined in Rule
13d-3 promulgated under the Exchange Act, of such Major Investor (“Investor Beneficial Owners”); provided that each such Affiliate or Investor Beneficial Owner (i) is not a
Competitor or FOIA Party, unless such party’s purchase of New Securities is otherwise consented to by the Board of Directors, (ii) agrees to enter into this Agreement and each of the Amended and Restated Voting Agreement and the Amended
and Restated Right of First Refusal and Co-Sale Agreement of even date herewith among 

  
 16 

 
the Company, the Investors and the other parties named therein, as an “Investor” under each such agreement (provided that any Competitor or FOIA Party shall not be
entitled to any rights as a Major Investor under Subsections 3.1, 3.2 and 4.1 hereof), and (iii) agrees to purchase at least such number of New Securities as are allocable hereunder to the Major Investor holding the fewest
number of shares of Preferred Stock and any other Derivative Securities. 
 (a) The Company shall give notice (the “Offer
Notice”) to each Major Investor, stating (i) its bona fide intention to offer such New Securities, (ii) the number of such New Securities to be offered, and (iii) the price and terms, if any, upon which it proposes to offer
such New Securities. 
 (b) By notification to the Company within 20 days after the Offer Notice is given, each Major Investor may elect to
purchase or otherwise acquire, at the price and on the terms specified in the Offer Notice, up to that portion of such New Securities which equals the proportion that the Common Stock then held by such Major Investor (including all shares of Common
Stock then issuable (directly or indirectly) upon conversion and/or exercise, as applicable, of the Preferred Stock and any other Derivative Securities then held by such Major Investor) bears to the total Common Stock of the Company then held by all
the Major Investors (including all shares of Common Stock issuable (directly or indirectly) upon conversion and/or exercise, as applicable, of the Preferred Stock and other Derivative Securities then held by the Major Investors). At the expiration
of such 20 day period, the Company shall promptly notify each Major Investor that elects to purchase or acquire all the shares available to it (each, a “Fully Exercising Investor”) of any other Major Investor’s failure to do
likewise. During the 10 day period commencing after the Company has given such notice, each Fully Exercising Investor may, by giving notice to the Company, elect to purchase or acquire, in addition to the number of shares specified above, up to that
portion of the New Securities for which Major Investors were entitled to subscribe but that were not subscribed for by the Major Investors which is equal to the proportion that the Common Stock issued and held, or issuable (directly or indirectly)
upon conversion and/or exercise, as applicable, of Preferred Stock and any other Derivative Securities then held, by such Fully Exercising Investor bears to the Common Stock issued and held, or issuable (directly or indirectly) upon conversion
and/or exercise, as applicable, of the Preferred Stock and any other Derivative Securities then held, by all Fully Exercising Investors who wish to purchase such unsubscribed shares. The closing of any sale pursuant to this Subsection
4.1(b) shall occur within the later of 120 days of the date that the Offer Notice is given and the date of initial sale of New Securities pursuant to Subsection 4.1(c). 

(c) If all New Securities referred to in the Offer Notice are not elected to be purchased or acquired as provided in Subsection
4.1(b), the Company may, during the 90 day period following the expiration of the periods provided in Subsection 4.1(b), offer and sell the remaining unsubscribed portion of such New Securities to any Person or Persons at a price not less
than, and upon terms no more favorable to the offeree than, those specified in the Offer Notice. If the Company does not enter into an agreement for the sale of the New Securities within such period, or if such agreement is not consummated within 30
days of the execution thereof, the right provided hereunder shall be deemed to be revived and such New Securities shall not be offered unless first reoffered to the Major Investors in accordance with this Subsection 4.1. 

(d) The right of first offer in this Subsection 4.1 shall not be applicable to (i) Exempted Securities (as defined in the
Company’s certificate of incorporation); and (ii) shares of Common Stock issued in the IPO. 
 (e) Notwithstanding any provision
hereof to the contrary, in lieu of complying with the provisions of this Subsection 4.1, the Company may elect to give notice to the Major Investors within 30 days after the issuance of New Securities. Such notice shall describe the
type, price, and terms 

  
 17 

 
of the New Securities. Each Major Investor shall have 20 days from the date notice is given to elect to purchase up to the number of New Securities that would, if purchased by such Major
Investor, maintain such Major Investor’s percentage-ownership position, calculated as set forth in Subsection 4.1(b) before giving effect to the issuance of such New Securities. The closing of such sale shall occur within 60 days of the
date notice is given to the Major Investors. 
 4.2 Termination. 

The covenants set forth in Subsection 4.1 shall terminate and be of no further force or effect (i) immediately before the
consummation of the IPO, (ii) when the Company first becomes subject to the periodic reporting requirements of Section 12(g) or 15(d) of the Exchange Act, or (iii) upon a Deemed Liquidation Event, as such term is defined in the
Company’s certificate of incorporation, whichever event occurs first. 
 5. Public Offering Participation Right. 

5.1 Public Offering. 
 In
connection with the Company’s IPO, the Company shall, within a reasonable period of time preceding the consummation of the IPO, offer each of RTW and ATP (each, a “Specified Investor,” collectively, the “Specified
Investors”) the opportunity to purchase shares of Common Stock to be sold in the IPO (without regard to the exercise of any over-allotment option by the underwriters to the IPO)at the same price per share at which the securities offered in
the IPO are being offered to the public (such right, the “Public Offering Participation Right”). If a Specified Investor exercises its Public Offering Participation Right, such Specified Investor shall have the right to purchase up
to a number of shares of Common Stock to be sold in the IPO equal to (i) the Participation Right Percentage (as defined below), multipled by, (ii) the aggregate number of shares of Common Stock to be sold in the IPO. Each Specified
Investor may assign its Public Offering Participation Right to an Affiliate. For the avoidance of doubt, nothing in this Section 5 shall limit the number of shares that each Specified Investor or its Affiliates may acquire
in an IPO outside of its Public Offering Participation Right. For purposes of this Section 5, the “Participation Right Percentage” applicable to both RTW and ATP shall be a fraction, the numerator of which shall be equal to one
and a half times (1.5x) the number of shares of Common Stock then held by RTW (including all shares of Common Stock then issuable (directly or indirectly) upon conversion and/or exercise, as applicable, of the Preferred Stock and any other
Derivative Securities then held by RTW) and the denominator of which shall be the total number of outstanding shares of the Company’s Common Stock (including all shares of Common Stock issuable (directly or indirectly) upon conversion and/or
exercise, as applicable, of the Preferred Stock and other Derivative Securities then outstanding). 
 5.2 Private Placement. 

(a) Notwithstanding the foregoing Section 5.1, 

(i) in the event that the Company is advised by the SEC, the Financial Industry Regulatory Authority (“FINRA”), any stock
exchange on which the Company’s shares are to be traded (“Exchange”) or any other regulatory body (or any of their staffs), that the offering or sale of such securities to the Specified Investors as described above in
Subsection 5.1 would violate any federal or state securities laws or the rules or regulations of the SEC, FINRA, Exchange, or any other regulatory body, then the Company shall offer to each Specified Investor the right to purchase in a
separate private placement (which shall be conducted, in whole or in part, concurrently with the IPO and the closing of which shall be contingent on the closing of the IPO) up to that number of shares of Common Stock such Specified Investor

  
 18 

 
would have been entitled to purchase pursuant to Subsection 5.1, at the price per share of the securities offered in the IPO (before excluding underwriters’ discounts and
commissions); and 
 (ii) in the event that the managing underwriter(s) advise(s) the Specified Investors that marketing factors require a
limitation on the number of shares to be underwritten and request(s) that the Specified Investors’ Public Offering Participation Right be subject to carve-backs, restrictions or other limitations (the “Cutback”), which Cutback
shall be applied equally to each of the Specified Investors, then the Company shall offer to each Specified Investor the right to purchase, in a separate private placement (which may be conducted, in whole or in part, concurrently with the IPO), up
to the difference between the number of shares of Common Stock such Specified Investor would have been able to purchase pursuant to Subsection 5.1 but for the Cutback and the number of shares such Specified Investor was actually permitted to
purchase in the IPO pursuant to Subsection 5.1, at the price per share of the securities offered in the IPO (before excluding underwriters’ discounts and commissions) (Subsections 5.2(a)(i) and (ii) collectively, the
“Private Sale Participation Right”). 
 (b) Notwithstanding the foregoing, each Specified Investor agrees that (i) in
no event shall the Private Sale Participation Right be exercised in such a manner that, in the reasonable determination of the managing underwriter(s), would materially and adversely affect the IPO and (ii) the number of shares each Specified
Investor is entitled to purchase may be reduced or modified to the extent reasonably requested by the Company’s underwriter(s) as to not cause such material and adverse effect on the IPO, which reduction or modification shall be applied equally
to each of the Specified Investors. 
 (c) If a Specified Investor exercises its Private Sale Participation Right, the Company and such
Specified Investor shall execute and deliver such documents that are (i) customary for a transaction structured as a concurrent private placement with a public offering and (ii) reasonably satisfactory to the Company, such Specified
Investor and the managing underwriter(s), if applicable. 
 5.3 Compliance. 

All offers to be made to the Specified Investors under this Section 5 shall be conducted in compliance with all
federal and state securities laws and regulations and all applicable rules, regulations and policies of the SEC, any exchange on which the Company’s shares are to be listed, or any other regulatory body. 

5.4 This Agreement Not an Offer. 

This Agreement does not constitute an offer to sell securities of the Company in an IPO. Any offering of the Company’s securities in an
IPO will only be made pursuant to a prospectus filed with the SEC. 
 6. Additional Covenants. 

6.1 Insurance. 
 The
Company shall use its commercially reasonable efforts to maintain, from financially sound and reputable insurers, Directors and Officers liability insurance in an amount and on terms and conditions satisfactory to the Board of Directors until such
time as the Board of Directors determines that such insurance should be discontinued. Notwithstanding any other provision of this Subsection 6.1 to the contrary, for so long as a Preferred Director (as defined in the Company’s
certificate of incorporation) is serving on the Board of Directors, the Company shall not cease to maintain a Directors and Officers liability insurance policy in an amount of at least $2,000,000 unless approved by such Preferred

  
 19 

 
Director, and the Company shall annually, within 120 days after the end of each fiscal year of the Company, deliver to the holders of Preferred Stock a certification that such a Directors and
Officers liability insurance policy remains in effect. 
 6.2 Employee Agreements. 

The Company will cause each person now or hereafter employed by it or by any subsidiary (or engaged by the Company or any subsidiary as a
consultant/independent contractor) with access to confidential information and/or trade secrets to enter into a nondisclosure and proprietary rights assignment agreement, and with respect to each person now or hereafter employed by the Company or
any subsidiary, such agreement shall include one-year or six-month noncompetition and non-solicitation provisions, unless
otherwise approved by the Board of Directors. In addition, the Company shall not amend, modify, terminate, waive, or otherwise alter, in whole or in part, any of the above-referenced agreements or any restricted stock agreement between the Company
and any employee, without the unanimous consent of the Preferred Directors. 
 6.3 Employee Stock. 

Unless otherwise approved by the Board of Directors, all future employees and consultants of the Company who purchase, receive options to
purchase, or receive awards of shares of the Company’s capital stock after the date hereof shall be required to execute restricted stock or option agreements, as applicable, providing for (a) vesting of shares over a four year period, with
the first 25% of such shares vesting following 12 months of continued employment or service, and the remaining shares vesting in equal monthly installments over the following 36 months, and (b) a market
stand-off provision substantially similar to that in Subsection 2.11. In addition, unless otherwise approved by the Board of Directors, the Company shall retain a “right of first
refusal” on employee transfers until the Company’s IPO and shall have the right to repurchase unvested shares at cost upon termination of employment of a holder of restricted stock. 

6.4 Matters Requiring Investor Director Approval. 

So long as the holders of Preferred Stock are entitled to elect a Preferred Director, the Company hereby covenants and agrees with each of the
Investors that it shall not, without approval of the Board of Directors, which approval must include the affirmative vote of both of the Preferred Directors: 

(a) incur any aggregate indebtedness in excess of $100,000; 

(b) make, or permit any subsidiary to make, any loan or advance to, or own any stock or other securities of, any subsidiary or other
corporation, partnership, or other entity unless it is wholly owned by the Company; 
 (c) make, or permit any subsidiary to make, any loan
or advance to any Person, including, without limitation, any employee or director of the Company or any subsidiary, except advances and similar expenditures in the ordinary course of business or under the terms of an employee stock or option plan
approved by the Board of Directors; 
 (d) guarantee, directly or indirectly, or permit any subsidiary to guarantee, directly or indirectly,
any indebtedness except for trade accounts of the Company or any subsidiary arising in the ordinary course of business; 

  
 20 

 (e) make any capital expenditures in excess of $100,000 that are not already included in a
budget approved by the Board of Directors, other than trade credit incurred in the ordinary course of business; 
 (f) otherwise enter into
or be a party to any transaction with any director, officer, or employee of the Company or any “associate” (as defined in Rule 12b-2 promulgated under the Exchange Act) of any such Person, except for
transactions contemplated by this Agreement and the Purchase Agreement; transactions resulting in payments to or by the Company in an aggregate amount less than $60,000 per year; or transactions made in the ordinary course of business and pursuant
to reasonable requirements of the Company’s business and upon fair and reasonable terms that are approved by a majority of the Board of Directors; 

(g) grant any stock option or stock equivalent providing for vesting provisions that differ from the Company’s standard vesting schedule
or acceleration of vesting upon a change of control of the Company, sale of all or substantially all assets of the Company, termination or similar event; 

(h) increase the number of shares reserved for issuance under the Company’s equity incentive plans; 

(i) create any committee of the Board of Directors; 

(j) acquire any corporation, partnership or other entity (whether by stock or asset purchase, merger, consolidation or otherwise); 

(k) sell, assign, license, pledge, or encumber material technology or intellectual property, other than licenses granted in the ordinary
course of business; or 
 (l) establish or invest in any subsidiary or joint venture; 

(m) change the Company’s independent accountants; 

(n) approve the annual operating and capital budgets of the Company; 

(o) materially change the principal business of the Company or enter material new lines of business; 

(p) change the location of the Company’s executive office; 

(q) grant any salaries for new or existing employees in excess of $200,000 per year; or 

(r) hire or terminate the senior executive officers or materially change the compensation of any senior executive officers. 

6.5 Board Matters. 

Unless otherwise determined by the vote of a majority of the directors then in office, the Board of Directors shall meet at least quarterly in
accordance with an agreed-upon schedule. The Company shall reimburse the nonemployee directors for all reasonable out-of-pocket travel expenses incurred (consistent with
the Company’s travel policy) in connection with attending meetings of the Board of Directors. 

  
 21 

 6.6 Successor Indemnification. 

If the Company or any of its successors or assignees consolidates with or merges into any other Person and is not the continuing or surviving
corporation or entity of such consolidation or merger, then to the extent necessary, proper provision shall be made so that the successors and assignees of the Company assume the obligations of the Company with respect to indemnification of members
of the Board of Directors as in effect immediately before such transaction, whether such obligations are contained in the Company’s bylaws, its certificate of incorporation, or elsewhere, as the case may be. 

6.7 Expenses of Counsel. 

In the event of a transaction which is a Sale of the Company (as defined in the Second Amended and Restated Voting Agreement of even date
herewith among the Company, the Investors and the other parties named therein), the reasonable fees and disbursements of one counsel for the Major Investors (“Investor Counsel”), in their capacities as stockholders, shall be borne
and paid by the Company. At the outset of considering a transaction which, if consummated would constitute a Sale of the Company, the Company shall obtain the ability to share with the Investor Counsel (and such counsel’s clients) and shall
share the confidential information (including, without limitation, the initial and all subsequent drafts of memoranda of understanding, letters of intent and other transaction documents and related noncompete, employment, consulting and other
compensation agreements and plans) pertaining to and memorializing any of the transactions which, individually or when aggregated with others would constitute the Sale of the Company. The Company shall be obligated to share (and cause the
Company’s counsel and investment bankers to share) such materials when distributed to the Company’s executives and/or any one or more of the other parties to such transaction(s). In the event that Investor Counsel deems it appropriate, in
its reasonable discretion, to enter into a joint defense agreement or other arrangement to enhance the ability of the parties to protect their communications and other reviewed materials under the attorney client privilege, the Company shall, and
shall direct its counsel to, execute and deliver to Investor Counsel and its clients such an agreement in form and substance reasonably acceptable to Investor Counsel. In the event that one or more of the other party or parties to such transactions
require the clients of Investor Counsel to enter into a confidentiality agreement and/or joint defense agreement in order to receive such information, then the Company shall share whatever information can be shared without entry into such agreement
and shall, at the same time, in good faith work expeditiously to enable Investor Counsel and its clients to negotiate and enter into the appropriate agreement(s) without undue burden to the clients of Investor Counsel. 

6.8 Indemnification Matters. 

The Company hereby acknowledges that one or more of the directors nominated to serve on the Board of Directors by the Investors (each a
“Fund Director”) may have certain rights to indemnification, advancement of expenses and/or insurance provided by one or more of the Investors and certain of their affiliates (collectively, the “Fund
Indemnitors”). The Company hereby agrees (i) that it is the indemnitor of first resort (i.e., its obligations to any such Fund Director are primary and any obligation of the Fund Indemnitors to advance expenses or to
provide indemnification for the same expenses or liabilities incurred by such Fund Director are secondary), (ii) that it shall be required to advance the full amount of expenses incurred by such Fund Director and shall be liable for the full amount
of all expenses, judgments, penalties, fines and amounts paid in settlement by or on behalf of any such Fund Director to the extent legally permitted and as required by the Company’s certificate of incorporation or bylaws (or any agreement
between the Company and such Fund Director), without regard to any rights such Fund Director may have against the Fund Indemnitors, and, (iii) that it irrevocably waives, relinquishes and releases the Fund Indemnitors from any and all claims
against the Fund Indemnitors for contribution, subrogation or any other recovery of any kind in respect thereof. The Company further agrees that no advancement or 

  
 22 

 
payment by the Fund Indemnitors on behalf of any such Fund Director with respect to any claim for which such Fund Director has sought indemnification from the Company shall affect the foregoing
and the Fund Indemnitors shall have a right of contribution and/or be subrogated to the extent of such advancement or payment to all of the rights of recovery of such Fund Director against the Company. 

6.9 Right to Conduct Activities. 

The Company hereby agrees and acknowledges that each of ATP and RTW is a professional investment fund, and as such invests in numerous
portfolio companies, some of which may be deemed competitive with the Company’s business (as currently conducted or as currently propose to be conducted). The Company hereby agrees that, to the extent permitted under applicable law,
neither ATP nor RTW shall be liable to the Company for any claim arising out of, or based upon, (a) the investment by ATP or RTW in any entity competitive with the Company, or (b) actions taken by any partner, officer or other
representative of ATP or RTW to assist any such competitive company, whether or not such action was taken as a member of the board of directors of such competitive company or otherwise, and whether or not such action has a detrimental effect on the
Company; provided, however, that the foregoing shall not relieve (i) any of the Investors from liability associated with the unauthorized disclosure of the Company’s confidential information obtained pursuant to this Agreement, or
(ii) any director or officer of the Company from any liability associated with his or her fiduciary duties to the Company. 
 6.11
FCPA.
 The Company represents that it shall not (and shall not permit any of its subsidiaries or affiliates or any of its or their
respective directors, officers, managers, employees, independent contractors, representatives or agents to) promise, authorize or make any payment to, or otherwise contribute any item of value to, directly or indirectly, to any third party,
including any Non-U.S. Official (as (as such term is defined in the U.S. Foreign Corrupt Practices Act of 1977, as amended (the “FCPA”)), in each case, in violation of the FCPA, the U.K.
Bribery Act, or any other applicable anti-bribery or anti-corruption law. The Company further represents that it shall (and shall cause each of its subsidiaries and affiliates to) cease all of its or their respective activities, as well as remediate
any actions taken by the Company, its subsidiaries or affiliates, or any of their respective directors, officers, managers, employees, independent contractors, representatives or agents in violation of the FCPA, the U.K. Bribery Act, or any other
applicable anti-bribery or anti-corruption law. The Company further represents that it shall (and shall cause each of its subsidiaries and affiliates to) maintain systems of internal controls (including, but not limited to, accounting systems,
purchasing systems and billing systems) to ensure compliance with the FCPA, the U.K. Bribery Act, or any other applicable anti-bribery or anti-corruption law. Upon request, the Company agrees to provide responsive information and/or
certifications concerning its compliance with applicable anti-corruption laws. The Company shall promptly notify each Investor if the Company becomes aware of any Enforcement Action (as defined in the Purchase Agreement). The Company
shall, and shall cause any direct or indirect subsidiary or entity controlled by it, whether now in existence or formed in the future, to comply with the FCPA. The Company shall use its best efforts to cause any direct or indirect subsidiary,
whether now in existence or formed in the future, to comply in all material respects with all applicable laws. 
 6.12 Termination of
Covenants. 
 The covenants set forth in this Section 6, except for Subsections 6.7 and
6.8, shall terminate and be of no further force or effect (a) immediately before the consummation of the IPO or (b) when the Company first becomes subject to the periodic reporting requirements of Section 12(g) or 15(d) of the
Exchange Act, or (c) upon a Deemed Liquidation Event, as such term is defined in the Company’s certificate of incorporation, whichever event occurs first. 

  
 23 

 7. Miscellaneous. 

7.1 Successors and Assigns. 

The rights under this Agreement may be assigned (but only with all related obligations) by a Holder to a transferee of Registrable
Securities that (a) is an Affiliate of a Holder; (b) is a Holder’s Immediate Family Member or trust for the benefit of an individual Holder or one or more of such Holder’s Immediate Family Members; or (c) after such
transfer, holds at least two percent of the shares of Registrable Securities (subject to appropriate adjustment for stock splits, stock dividends, combinations, and other recapitalizations); provided, however, that (i) the Company
is, within a reasonable time after such transfer, furnished with written notice of the name and address of such transferee and the Registrable Securities with respect to which such rights are being transferred; and (ii) such transferee agrees
in a written instrument delivered to the Company to be bound by and subject to the terms and conditions of this Agreement, including the provisions of Subsection 2.11. For the purposes of determining the number of shares of Registrable
Securities held by a transferee, the holdings of a transferee (x) that is an Affiliate or stockholder of a Holder; (y) who is a Holder’s Immediate Family Member; or (z) that is a trust for the benefit of an individual Holder or
such Holder’s Immediate Family Member shall be aggregated together and with those of the transferring Holder; provided further that all transferees who would not qualify individually for assignment of rights shall have a single attorney-in-fact for the purpose of exercising any rights, receiving notices, or taking any action under this Agreement. The terms and conditions of this Agreement inure to
the benefit of and are binding upon the respective successors and permitted assignees of the parties. Nothing in this Agreement, express or implied, is intended to confer upon any party other than the parties hereto or their respective successors
and permitted assignees any rights, remedies, obligations or liabilities under or by reason of this Agreement, except as expressly provided herein. 

7.2 Governing Law. 
 This
Agreement shall be governed by the internal law of the State of Delaware. 
 7.3 Counterparts. 

This Agreement may be executed in two or more counterparts, each of which shall be deemed an original, but all of which together shall
constitute one and the same instrument. Counterparts may be delivered via facsimile, electronic mail (including pdf or any electronic signature complying with the U.S. federal ESIGN Act of 2000, e.g., www.docusign.com) or other transmission
method and any counterpart so delivered shall be deemed to have been duly and validly delivered and be valid and effective for all purposes. 

7.4 Titles and Subtitles. 

The titles and subtitles used in this Agreement are for convenience only and are not to be considered in construing or interpreting this
Agreement. 
 7.5 Notices. 

All notices and other communications given or made pursuant to this Agreement shall be in writing and shall be deemed effectively given upon
the earlier of actual receipt or (a) personal delivery to the party to be notified; (b) when sent, if sent by electronic mail or facsimile during the recipient’s normal business hours, and if not sent during normal business hours,
then on the recipient’s next business day; (c) five days after having been sent by registered or certified mail, return receipt requested, postage prepaid; or (d) one business day after the business day of deposit with a nationally
recognized overnight 

  
 24 

 
courier, freight prepaid, specifying next-day delivery, with written verification of receipt. All communications shall be sent to the respective parties at
their addresses as set forth on Schedule A hereto, or to the principal office of the Company and to the attention of the Chief Executive Officer, in the case of the Company, or to such email address, facsimile number, or address as
subsequently modified by written notice given in accordance with this Subsection 7.5. If notice is given to the Company, a copy shall also be sent to Fenwick & West LLP, 1191 Second Avenue, 10th Floor, Seattle, WA 98101, Attn: Alan
C. Smith; email: asmith@fenwick.com and if notice is given to Investors, a copy shall also be given to Covington & Burling LLP , 620 Eighth Avenue, New York, NY 10018 , Attn: Brian Rosenzweig; email: brosenzweig@cov.com; and to Hogan
Lovells (US) LLP, 100 International Drive, Suite 2000, Baltimore, Maryland 21202, Attn: Asher M. Rubin; email: asher.rubin@hoganlovells.com; facsimile (410) 659-2701. 

7.6 Amendments and Waivers. 

Any term of this Agreement may be amended and the observance of any term of this Agreement may be waived (either generally or in a particular
instance, and either retroactively or prospectively) only with the written consent of the Company and the Requisite Holders; provided that the Company may in its sole discretion waive compliance with Subsection 2.12(c) (and the
Company’s failure to object promptly in writing after notification of a proposed assignment allegedly in violation of Subsection 2.12(c) shall be deemed to be a waiver); and provided further that any provision hereof may be waived
by any waiving party on such party’s own behalf, without the consent of any other party. Notwithstanding the foregoing, (a) this Agreement may not be amended or terminated and the observance of any term hereof may not be waived with
respect to any Investor without the written consent of such Investor, unless such amendment, termination, or waiver applies to all Investors in the same fashion (it being agreed that, subject to the following sentence, a waiver of the provisions of
Section 4 with respect to a particular transaction shall be deemed to apply to all Investors in the same fashion if such waiver does so by its terms, notwithstanding the fact that certain Investors may nonetheless, by
agreement with the Company, purchase securities in such transaction), (b) Subsection 3.4(a) and this clause (b) of Subsection 7.6 may not be amended, modified, terminated or waived without the written consent of RTW,
(c) Subsection 3.4(d) and this clause (c) of Subsection 7.6 may not be amended, modified, terminated or waived without the written consent of RA Capital and (d) Section 5 and this clause (d) of Subsection
7.6 may not be amended, modified, terminate or waived without the written consent of each of RTW and ATP. Notwithstanding the foregoing, if, after giving effect to any waiver of Section 4 or any provision pertaining to
Section 4 with respect to a particular transaction, a Major Investor purchases securities in such transaction or issuance (such Major Investor, a “Participating Investor”), such waiver of the
provisions of Section 4 shall be deemed to apply to the other Major Investors only if the Company shall have provided such other Major Investors the opportunity to purchase a proportional number of the securities in such transaction based on
the pro rata purchase right of each Major Investor set forth in Section 4, assuming a transaction size determined based upon the amount purchased by the Participating Investor that invested the largest percentage in such
transaction. The Company shall give prompt notice of any amendment or termination hereof or waiver hereunder to any party hereto that did not consent in writing to such amendment, termination, or waiver. Any amendment, termination, or waiver
effected in accordance with this Subsection 7.6 shall be binding on all parties hereto, regardless of whether any such party has consented thereto. No waivers of or exceptions to any term, condition, or provision of this Agreement, in any one
or more instances, shall be deemed to be or construed as a further or continuing waiver of any such term, condition, or provision. 
 7.7
Severability. 
 In case any one or more of the provisions contained in this Agreement is for any reason held to be invalid, illegal
or unenforceable in any respect, such invalidity, illegality, or unenforceability shall not affect any other provision of this Agreement, and such invalid, illegal, or unenforceable provision 

  
 25 

 
shall be reformed and construed so that it will be valid, legal, and enforceable to the maximum extent permitted by law. 

7.8 Aggregation of Stock. 

All shares of Registrable Securities held or acquired by Affiliates shall be aggregated together for the purpose of determining the
availability of any rights under this Agreement and such Affiliated persons may apportion such rights as among themselves in any manner they deem appropriate. 

7.9 Additional Investors. 

Notwithstanding anything to the contrary contained herein, if the Company issues additional shares of the Company’s Series B Preferred
Stock after the date hereof, whether pursuant to the Purchase Agreement or otherwise, any purchaser of such shares of Series B Preferred Stock may become a party to this Agreement by executing and delivering an additional counterpart signature page
to this Agreement, and thereafter shall be deemed an “Investor” for all purposes hereunder. No action or consent by the Investors shall be required for such joinder to this Agreement by such additional Investor, so long as such additional
Investor has agreed in writing to be bound by all of the obligations as an “Investor” hereunder. 
 7.10 Entire Agreement.

 This Agreement (including any Schedules and Exhibits hereto) constitutes the full and entire understanding and agreement among the
parties with respect to the subject matter hereof, and any other written or oral agreement relating to the subject matter hereof existing between the parties is expressly canceled. Upon the effectiveness of this Agreement, the Prior Agreement shall
be deemed amended and restated and superseded and replaced in its entirety by this Agreement, and shall be of no further force or effect. 

7.11 Dispute Resolution. 

The parties (a) hereby irrevocably and unconditionally submit to the jurisdiction of the state courts of Delaware and to the jurisdiction
of the United States District Court for the District of Delaware for the purpose of any suit, action or other proceeding arising out of or based upon this Agreement, (b) agree not to commence any suit, action or other proceeding arising out of
or based upon this Agreement except in the state courts of Delaware or the United States District Court for the District of Delaware, and (c) hereby waive, and agree not to assert, by way of motion, as a defense, or otherwise, in any
such suit, action or proceeding, any claim that it is not subject personally to the jurisdiction of the above-named courts, that its property is exempt or immune from attachment or execution, that the suit, action or proceeding is brought in an
inconvenient forum, that the venue of the suit, action or proceeding is improper or that this Agreement or the subject matter hereof may not be enforced in or by such court. 

WAIVER OF JURY TRIAL: EACH PARTY HEREBY WAIVES ITS RIGHTS TO A JURY TRIAL OF ANY CLAIM OR CAUSE OF ACTION BASED UPON OR ARISING OUT OF THIS
AGREEMENT, THE OTHER TRANSACTION DOCUMENTS, THE SECURITIES OR THE SUBJECT MATTER HEREOF OR THEREOF. THE SCOPE OF THIS WAIVER IS INTENDED TO BE ALL-ENCOMPASSING OF ANY AND ALL DISPUTES THAT MAY BE FILED IN ANY
COURT AND THAT RELATE TO THE SUBJECT MATTER OF THIS TRANSACTION, INCLUDING, WITHOUT LIMITATION, CONTRACT CLAIMS, TORT CLAIMS (INCLUDING NEGLIGENCE), BREACH OF DUTY CLAIMS, AND ALL OTHER COMMON LAW AND STATUTORY CLAIMS. THIS SECTION HAS BEEN FULLY
DISCUSSED BY EACH OF THE PARTIES HERETO AND THESE PROVISIONS 

  
 26 

 
WILL NOT BE SUBJECT TO ANY EXCEPTIONS. EACH PARTY HERETO HEREBY FURTHER WARRANTS AND REPRESENTS THAT SUCH PARTY HAS REVIEWED THIS WAIVER WITH ITS LEGAL COUNSEL, AND THAT SUCH PARTY KNOWINGLY AND
VOLUNTARILY WAIVES ITS JURY TRIAL RIGHTS FOLLOWING CONSULTATION WITH LEGAL COUNSEL. 
 Each party will bear its own costs in respect of any
disputes arising under this Agreement. The prevailing party shall be entitled to reasonable attorney’s fees, costs, and necessary disbursements in addition to any other relief to which such party may be entitled. Each of the parties to this
Agreement consents to personal jurisdiction for any equitable action sought in the U.S. District Court for the District of Delaware or any court of the State of Delaware having subject matter jurisdiction. 

7.12 Delays or Omissions. 

No delay or omission to exercise any right, power, or remedy accruing to any party under this Agreement, upon any breach or default of any
other party under this Agreement, shall impair any such right, power, or remedy of such nonbreaching or nondefaulting party, nor shall it be construed to be a waiver of or acquiescence to any such breach or default, or to any similar breach or
default thereafter occurring, nor shall any waiver of any single breach or default be deemed a waiver of any other breach or default theretofore or thereafter occurring. All remedies, whether under this Agreement or by law or otherwise afforded to
any party, shall be cumulative and not alternative. 
 7.13 Acknowledgment. 

The Company acknowledges that the Investors are in the business of venture capital investing and therefore review the business plans and
related proprietary information of many enterprises, including enterprises which may have products or services which compete directly or indirectly with those of the Company. Nothing in this Agreement shall preclude or in any way restrict the
Investors from investing or participating in any particular enterprise whether or not such enterprise has products or services which compete with those of the Company. 

[Remainder of Page Intentionally Left Blank] 

  
 27 

 IN WITNESS WHEREOF, the parties have executed this Second Amended and Restated
Investors’ Rights Agreement as of the date first written above. 
  

			
	STOKE THERAPEUTICS, INC.
		
	By:	 	/s/ Edward Kaye
	Name: Edward Kaye, M.D.
	Title: Chief Executive Officer

  

[SIGNATURE PAGE TO STOKE THERAPEUTICS, INC.
SECOND AMENDED AND RESTATED 
 INVESTORS’
RIGHTS AGREEMENT] 

 IN WITNESS WHEREOF, the parties have executed this Second Amended and Restated
Investors’ Rights Agreement as of the date first written above. 
  

			
	INVESTORS:
	
	RTW MASTER FUND, LTD.
		
	By:	 	/s/ Roderick Wong
	
	Name: Roderick Wong, M.D.
	Title: Director

  

			
	RTW INNOVATION MASTER FUND, LTD.
		
	By:	 	/s/ Roderick Wong
	
	Name: Roderick Wong, M.D.
	Title: Director

  

[SIGNATURE PAGE TO STOKE THERAPEUTICS, INC.
SECOND AMENDED AND RESTATED 
 INVESTORS’
RIGHTS AGREEMENT] 

 IN WITNESS WHEREOF, the parties have executed this Second Amended and Restated
Investors’ Rights Agreement as of the date first written above. 
  

			
	INVESTORS:
	
	APPLE TREE PARTNERS IV, L.P.
		
	By:	 	ATP III GP, LTD., General Partner
		
	By:	 	/s/ Seth L. Harrison
	Name: Seth L. Harrison
	Title: Director

  

[SIGNATURE PAGE TO STOKE THERAPEUTICS, INC.
SECOND AMENDED AND RESTATED 
 INVESTORS’
RIGHTS AGREEMENT] 

 IN WITNESS WHEREOF, the parties have executed this Second Amended and Restated
Investors’ Rights Agreement as of the date first written above. 
  

			
	INVESTORS:
	
	CORMORANT PRIVATE HEALTHCARE FUND I, LP
	By: Cormorant Private Healthcare GP, LLC
		
	By:	 	/s/ Bihua Chen
		 	Bihua Chen, Managing Member of the GP

  

			
	CORMORANT PRIVATE HEALTHCARE FUND II, LP
	By: Cormorant Private Healthcare GP, LLC
		
	By:	 	/s/ Bihua Chen
		 	Bihua Chen, Managing Member of the GP

  

			
	CORMORANT GLOBAL HEALTHCARE MASTER FUND, LP
	By: Cormorant Global Healthcare GP, LLC
		
	By:	 	/s/ Bihua Chen
		 	Bihua Chen, Managing Member of the GP

  

			
	CRMA SPV, LP
	By: Cormorant Asset Management, LLC, its Attorney-in-Fact
		
	By:	 	/s/ Bihua Chen
		 	Bihua Chen, CEO, Managing Member

  

[SIGNATURE PAGE TO STOKE THERAPEUTICS, INC.
SECOND AMENDED AND RESTATED 
 INVESTORS’
RIGHTS AGREEMENT] 

 IN WITNESS WHEREOF, the parties have executed this Second Amended and Restated
Investors’ Rights Agreement as of the date first written above. 
  

			
	INVESTORS:
	
	RA CAPITAL HEALTHCARE FUND, L.P.
	By: RA Capital Management, LLC
	Its: General Partner
		
	By:	 	/s/ James Schneider
	Name: James Schneider
	Title: Authorized Signatory

  

			
	BLACKWELL PARTNERS LLC – SERIES A
		
	By:	 	/s/ Abayomi A. Adigun

 
			
	Name:	 	Abayomi A. Adigun
	Title:	 	Investment Manager, DUMAC, Inc. Authorized Signatory

 
			
		
	By:	 	/s/ W. Brian Humphries

 
			
	Name:	 	W. Brian Humphries
	Title:	 	Assistant Treasurer, DUMAC, Inc. Authorized Signatory

  

[SIGNATURE PAGE TO STOKE THERAPEUTICS, INC.
SECOND AMENDED AND RESTATED 
 INVESTORS’
RIGHTS AGREEMENT] 

 IN WITNESS WHEREOF, the parties have executed this Second Amended and Restated
Investors’ Rights Agreement as of the date first written above. 
  

			
	INVESTORS:
	
	PERCEPTIVE LIFE SCIENCES MASTER FUND LTD
		
	By:	 	/s/ James H. Mannix
	Name: James H. Mannix
	Title: C.O.O.

  

[SIGNATURE PAGE TO STOKE THERAPEUTICS, INC.
SECOND AMENDED AND RESTATED 
 INVESTORS’
RIGHTS AGREEMENT] 

 IN WITNESS WHEREOF, the parties have executed this Second Amended and Restated
Investors’ Rights Agreement as of the date first written above. 
  

			
	INVESTORS:
	
	JANUS HENDERSON CAPITAL FUNDS PLC on behalf of its series Janus Henderson Global Life Sciences Fund
		
	By:	 	/s/ Andrew Acker
	Name: Andrew Acker
	Title: Portfolio Manager

  

[SIGNATURE PAGE TO STOKE THERAPEUTICS, INC.
SECOND AMENDED AND RESTATED 
 INVESTORS’
RIGHTS AGREEMENT] 

 IN WITNESS WHEREOF, the parties have executed this Second Amended and Restated
Investors’ Rights Agreement as of the date first written above. 
  

			
	INVESTORS:
	
	REDMILE BIOPHARMA INVESTMENTS I, L.P.
		
	By:	 	/s/ Jeremy Green
	Name: Jeremy Green
	Title: Managing Member of the General Partner and the Management Company

  

[SIGNATURE PAGE TO STOKE THERAPEUTICS, INC.
SECOND AMENDED AND RESTATED 
 INVESTORS’
RIGHTS AGREEMENT] 

 IN WITNESS WHEREOF, the parties have executed this Second Amended and Restated
Investors’ Rights Agreement as of the date first written above. 
  

			
	INVESTORS:
	
	SPHERA GLOBAL HEALTHCARE MASTER FUND, LP
		
	By:	 	/s/ Doron Breen
	Name: Doron Breen
	Title: Director

  

[SIGNATURE PAGE TO STOKE THERAPEUTICS, INC.
SECOND AMENDED AND RESTATED 
 INVESTORS’
RIGHTS AGREEMENT] 

 IN WITNESS WHEREOF, the parties have executed this Second Amended and Restated
Investors’ Rights Agreement as of the date first written above. 
  

			
	INVESTORS:
	
	 ALEXANDRIA VENTURE INVESTMENTS, LLC,

a Delaware limited liability company

		
	By:	 	 ALEXANDRIA REAL ESTATE EQUITIES, INC.,
 a
Maryland corporation, managing member

		
	By:	 	/s/ Aaron Jacobson
	Name: Aaron Jacobson
	Title: SVP – Venture Counsel

  

[SIGNATURE PAGE TO STOKE THERAPEUTICS, INC.
SECOND AMENDED AND RESTATED 
 INVESTORS’
RIGHTS AGREEMENT]EX-10.2

 EXHIBIT 10.2 

STOKE THERAPEUTICS, INC. 

2014 EQUITY INCENTIVE PLAN 

As Adopted on June 18, 2014 

Amended July 15, 2015 

Amended February 11, 2016 

Amended October 19, 2017 (Effective October 20, 2017) 

Amended January 4, 2018 

Amended October 12, 2018 (Effective October 15, 2018) 

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 46,276,642 Shares. Subject to Sections 2.2 and 11 hereof, Shares subject to Awards that are cancelled, forfeited, settled in cash, used to pay withholding obligations or pay the
exercise price of an Option or that expire by their terms at any time will again be available for grant and issuance in connection with other Awards. 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. 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 forfeited
or repurchased by the Company as a separate issuance) under the Plan upon exercise of ISOs exceed 92,553,284 Shares (adjusted in proportion to any adjustments under Section 2.2 hereof) over the term of the Plan (the “ISO
Limit”). Subject to Sections 2.2 and 11 hereof, in the event that the number of Shares reserved for issuance under the Plan is increased, the ISO Limit shall be automatically increased by such number of Shares such that the ISO Limit
equals (a) two (2) multiplied by (b) the number of Shares reserved for issuance under 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

  
 1 

 
under the Plan (a) the number of Shares reserved for issuance under this Plan, (b) the Exercise Prices of and number of Shares subject to outstanding Options and SARs, and (c) the
Purchase Prices of and/or number 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 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. 
 3. PLAN FOR BENEFIT OF SERVICE PROVIDERS. 

3.1 Eligibility. The Committee will have the authority to select persons to receive Awards. ISOs (as defined in
Section 4 hereof) 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 Parent or Subsidiary or limit in any way the right of the Company or any Parent or Subsidiary 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 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 

  
 2 

 
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 Parent or Subsidiary (“Ten Percent Stockholder”) will be exercisable
after the expiration of five (5) years from the date the ISO is granted. 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 unless expressly determined in writing by the Committee on the Option’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. 

4.5 Method of Exercise. Options may be exercised only by delivery to the Company of a written stock option
exercise agreement (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 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 payment of any applicable taxes. 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 13.3 hereof and notwithstanding
the 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 or as otherwise determined by the Committee. 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 

  
 3 

 
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, 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 by Participant on the Termination Date or as otherwise
determined by the Committee. 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, 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. 
 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 

 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. 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 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. 

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 or at the time the purchase is consummated. Payment of the Purchase Price must be made in accordance with Section 8 hereof. 

5.3 Dividends and Other Distributions. Participants holding Restricted Stock will be entitled to receive all
dividends and other distributions paid with respect to such Shares, unless the Committee provides otherwise at the time of award. 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 Shares of Restricted Stock with respect to which they were paid. 

  
 5 

 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, or by issuance of those Shares at a date in the future. No Purchase Price shall apply to an RSU settled in Shares. All grants of Restricted Stock Units will be evidenced by an Award 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. 

6.2 Form and Timing of Settlement. To the extent permissible under applicable law, the Committee may permit a
Participant to defer payment under a RSU to a date or dates after the RSU is earned, 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. Payment may be made in the form of cash or whole Shares or a combination thereof, all as the Committee determines. 

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), 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 settled. All grants of SARs made pursuant to this Plan will be evidenced by an Award 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. 
 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 Award Agreement governing such SAR. The Award Agreement shall set forth the Expiration Date; provided that
no SAR will be exercisable after the expiration of ten 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, and which may not be less than the Fair Market Value on the date of grant and may be settled in cash or in Shares. 

7.4 Termination. Subject to earlier termination pursuant to Sections 11 and 13.1 hereof and notwithstanding
the exercise periods set forth in the Award 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. SARs must be

  
 6 

 
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) 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 by Participant on the Termination
Date or as otherwise determined by the Committee. 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) 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 (by check) or, where expressly approved for the Participant by the Committee and where permitted by 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; 

(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 imputation of income under Sections 483 and 1274 of the Code; 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; 

  
 7 

 (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) subject to compliance with applicable law, 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. 

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 applicable tax withholding requirements prior to the delivery of any 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 the minimum tax withholding
obligation by electing to have the Company withhold from the Shares to be issued up to the minimum 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 minimum
amount to be withheld; 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 consequences to the Company. 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. 
 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, 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.

  
 8 

 
For the avoidance of doubt, the prohibition against assignment and transfer applies to a stock option and, prior to exercise , the shares to be issued on exercise of a stock option, 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). 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 Option 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, grants 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 federal and state securities laws, rules and regulations of any governmental body, and the requirements of any stock exchange or automated quotation system upon which the Shares 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 or other issuance. Notwithstanding any other provision in this Plan, the Company will have no obligation to issue 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 state or federal 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 state securities laws, stock exchange or automated quotation system, and the Company will have no liability for any inability or failure so do. 

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. 

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

  
 9 

 
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 the Company’s initial public offering of Common Stock pursuant to an effective registration statement filed under the Securities 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 Escrow; Pledge of Shares. To enforce any restrictions on a Participant’s Shares, the Committee may
require the Participant to deposit all 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 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. 

10.4 Securities Law Restrictions. All 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 federal, state or foreign securities law, or any rules, regulations and other
requirements of the SEC or any stock exchange or automated quotation system upon which the Shares 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 

  
 10 

 
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 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 payout of a Restricted Stock Unit, 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) of the Code). 
 (d) The full or partial
exercisability or vesting and accelerated expiration of outstanding Awards. 
 (e) The settlement of the full 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) with a Fair Market Value equal to the required amount, 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 

  
 11 

 
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. 

(f) The cancellation of outstanding Awards in exchange for no consideration. 

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
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) of the Code). In the event the Company elects to grant a new Option or SAR rather
than assuming an existing option or stock appreciation right, such new Option or SAR may be granted with a similarly adjusted Exercise Price. 

12. ADMINISTRATION. 

12.1 Committee Authority. This Plan will be administered by the Committee or the Board if no Committee is created
by the Board. 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; 

  
 12 

 (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; 

(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 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, any Exercise
Agreement or any Restricted Stock Purchase Agreement; 
 (k) determine whether an Award has been earned; 

(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 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 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 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 officers of the Company the authority to grant an Award under this Plan, provided that each such officer is a member of the Board. 

  
 13 

 12.3 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. 

12.4 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 Board 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; (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; and (c) in the event that initial stockholder approval is not obtained within the time period provided herein, any Shares issued pursuant to any such Award shall be canceled and any purchase of such Shares issued hereunder shall be
rescinded. 
 13.2 Term of Plan. Unless earlier terminated as provided herein, this Plan will automatically
terminate ten (10) years after the later of (i) the Effective Date, or (ii) the most recent increase in the number of Shares reserved under Section 2 that was approved by stockholders. 

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 or SARs 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. 

  
 14 

 “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 
 (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 (an “Acquisition by Sale of Assets”). 

“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 signed 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 executed
via written or electronic means. 
 “Board” means the Board of Directors of the Company. 

  
 15 

 “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 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 Stoke Therapeutics, Inc., or any successor corporation. 

“Disability” means that the Participant is unable to engage in any substantial gainful activity by reason of any
medically determinable physical or mental impairment that can be expected to result in death or can be expected to last for a continuous period of not less than 12 months. 

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

“Exercise Price” means the price per Share at which a holder of an Option may purchase Shares issuable upon exercise
of the Option. 
 “Fair Market Value” means, as of any date, the value of a share of the Company’s Common Stock
determined as follows: 
 (a) if such Common Stock 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 Common Stock is listed or admitted to trading as reported in The Wall Street Journal; 

(b) if such Common Stock is publicly traded but is not listed or admitted to trading on a national securities exchange, the average of the
closing bid and asked prices on the date of determination as reported by The Wall Street Journal (or, if not so reported, 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. 

  
 16 

 “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 2014 Equity 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 Commission under the Securities Act. 

“SEC” means the Securities and Exchange Commission. 

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

“Shares” means shares of the Company’s Common Stock 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. 
 “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, except that in no event 

  
 17 

 
may an Option be exercised after the expiration of the term set forth in the Stock Option Agreement. 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. 

* * * * * * * * * * * 

  
 18 

 STOKE THERAPEUTICS, INC. 

2014 EQUITY 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 Stoke Therapeutics, Inc., a Delaware corporation (the “Company”), and _____________
(“Purchaser”). Capitalized terms not defined herein shall have the meanings ascribed to them in the Company’s 2014 Equity 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 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. 

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. 

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 

  
 1 

 
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, upon the request of the Company or the underwriters managing any registered public offering of the Company’s securities,
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. 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 

  
 4 

 
issued with 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

  
 6 

 
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. 
 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 

 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 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 

  
 8 

 
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. 

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 

  
 9 

 
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] 

  
 10 

 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. 
  

									
	STOKE THERAPEUTICS, INC.	 	        	 	PURCHASER
				
	By:	 	                             
                                         
  	 		 	 
		 		 		 	    	 	
			
	Address:	 		 	Address:   __________________________________
	Fax No.:  (____) ____________________	 		 		 	__________________________________
		 		 		 	Fax No.:	 	(____) ____________________

  

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

  
 11 

 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 Stoke Therapeutics, Inc., 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 Signature

 EARLY EXERCISE FORM 

OPTION GRANT NO. ___ 

NOTICE OF STOCK OPTION GRANT 

STOKE THERAPEUTICS, INC. 

2014 EQUITY 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 Stoke Therapeutics, Inc., a Delaware corporation (the “Company”), pursuant to the Company’s 2014 Equity 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. 

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. 
  

									
	STOKE THERAPEUTICS, INC.	 		 	
					
	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 

STOKE THERAPEUTICS, INC. 

2014 EQUITY 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 Stoke Therapeutics, Inc., 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 2014 Equity 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 Error! Reference source not found. 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 to 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 or wire transfer), or where permitted by law: 
 (a) by cancellation of indebtedness of the Company owed
to Optionee; 

  
 2 

 (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; 

(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. 

4.4. Tax Withholding. Prior to the issuance of the Shares upon exercise of the Option, Optionee must pay or
provide for any applicable federal, state and local withholding obligations of the Company. If the Committee permits, Optionee may provide for payment of withholding taxes upon exercise of the Option by requesting that the Company retain the minimum
number of Shares with a Fair Market Value equal to the minimum amount of taxes required to be withheld; 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 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. 
 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 Section 25102(o) and Rule 701. Any provision of this Agreement that is inconsistent with Section 25102(o) or Rule 701 shall, without further act or amendment by the Company or the
Committee, be reformed to comply with the requirements of Section 25102(o) and/or 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 

  
 4 

 (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 Section 25102(o), 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. 
 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, if requested by the managing underwriter(s) in the initial underwritten
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 (the “IPO”), for a period of up to one hundred eighty
(180) days following the effective date of the registration statement relating to such 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

  
 5 

 
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. 
 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 

  
 6 

 
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. 
 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

  
 7 

 
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. 
 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 

  
 8 

 
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. 
 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

  
 9 

 
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 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. 

  
 10 

 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 

  
 11 

 ANNEX A 

FORM OF STOCK OPTION EXERCISE NOTICE AND AGREEMENT 

 EARLY EXERCISE FORM 

STOCK OPTION EXERCISE NOTICE AND AGREEMENT 

STOKE THERAPEUTICS, INC. 

2014 EQUITY INCENTIVE PLAN 

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

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

									
	Name:	 	      
	 		  	Social Security Number:	 	
                     
                    

	Address:	 	      

     
	 		  	Employee Number:	 	      

 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 “Stoke Therapeutics, Inc..”

  

	☐	 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.] 

 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 2014 Equity 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 

  
 2 

 EARLY EXERCISE FORM 

 

	 	
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. 

  

	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 Stoke Therapeutics, Inc., 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 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 (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 

STOKE THERAPEUTICS, INC. 

2014 EQUITY 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 Stoke Therapeutics, Inc., a Delaware corporation (the “Company”), pursuant to the Company’s 2014 Equity 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. 
 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. 
  

									
	Stoke Therapeutics, Inc.	 		 	
					
	By /Signature:	 	                             
           	 		 	Optionee Signature:	 	 

									
					
	Typed Name:	 	                             
                   	 		 	Optionee’s Name:	 	 

									
					
	Title:	 	                             
                               	 		 		 	

 ATTACHMENT: Exhibit A – Stock Option Agreement 

  
 51 

 Exhibit A 

Stock Option Agreement 

 EXHIBIT A 

STOCK OPTION AGREEMENT 

STOKE THERAPEUTICS, INC. 

2014 EQUITY 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 Stoke Therapeutics, Inc., 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 2014 Equity 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 Error! Reference source not found. 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 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 

  
 3 

 
“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; 
 (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. 
 4.4 Tax Withholding. Prior to the issuance of the Shares upon exercise of the Option,
Optionee must pay or provide for any applicable federal, state and local withholding obligations of the Company. If the Committee permits, Optionee may provide for payment of withholding taxes upon exercise of the Option by requesting that the
Company retain the minimum number of Shares with a Fair Market Value equal to the minimum amount of taxes required to be withheld; 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 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. 
 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 Section 25102(o) and Rule 701. Any provision of this Agreement that is inconsistent with Section 25102(o) or Rule 701 shall, without further act or amendment by the Company or the
Committee, be reformed to comply with the requirements of Section 25102(o) and/or 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 Section 25102(o), 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, if requested by the
managing underwriter(s) in the initial underwritten 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 (the “IPO”),
for a period of up to one hundred eighty (180) days following the effective date of the registration statement relating to such 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 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 

  
 5 

 
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. 

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 

  
 6 

 
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 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. 

  
 7 

 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. 
 (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. 

  
 8 

 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. 
 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 

  
 9 

 
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. 

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

  
 10 

 
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 

STOKE THERAPEUTICS, INC. 

2014 EQUITY INCENTIVE PLAN 

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

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

									
	Name:	 	      
	 		  	Social Security Number:	 	
                     
                    

	Address:	 	      

     
	 		  	Employee Number:	 	      

 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 “Stoke Therapeutics, Inc..” 

 

	☐	 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.] 

 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 2014 Equity 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 

  
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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. 

 

	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 to agrees to be bound by its terms 

 

					
	SIGNATURE:	 		 	DATE:
			
	      
	 		 	      

	Optionee’s Name:	 		 	

 [Signature Page to Stock Option Exercise Notice and Agreement] 

  
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