EX-4.2





 Exhibit 4.2 

AMENDED AND RESTATED INVESTORS’ RIGHTS AGREEMENT 

THIS AMENDED AND RESTATED INVESTORS’ RIGHTS AGREEMENT (this “Agreement”), is made as of January 25, 2021, by
and among Design Therapeutics, Inc., a Delaware corporation (the “Company”), each of the investors listed on Schedule A hereto, each of which is referred to in this Agreement as an “Investor”. 

RECITALS: 
 A. The
Company and certain of the Investors are parties to that certain Series B Preferred Stock Purchase Agreement of even date herewith (the “Purchase Agreement”). 

B. Certain of the Investors (the “Prior Investors”) are holders of Series A Preferred Stock and are parties to that
certain Investor Rights Agreement dated February 21, 2020, by and among the Company and Prior Investors (the “Prior Agreement”); 

C. The parties to the Prior Agreement desire to amend and restate the Prior Agreement in its entirety and accept the rights and
covenants created pursuant to this Agreement in lieu of their rights and covenants under the Prior Agreement; and 
 D. In order to
induce the Company to enter into the Purchase Agreement and to induce the Investors to invest funds in the Company pursuant to the Purchase Agreement, the Investors and the Company hereby agree that this Agreement shall govern the rights of the
Investors to cause the Company to register shares of Common Stock issuable to the Investors, to receive certain information from the Company, and to participate in future equity offerings by the Company, and shall govern certain other matters as set
forth in this Agreement. 
 The parties agree as follows: 

1. General. 
 1.1
Amendment and Restatement of Prior Agreement. The Prior Agreement is hereby amended in its entirety and restated herein. Such amendment and restatement is effective upon the execution of this Agreement by the Company and the holders of at least
55% of the Registrable Securities (as defined in the Prior Agreement) then outstanding held by the Prior Investors as of the date of this Agreement. Upon such execution, all provisions of, rights granted and covenants made in the Prior Agreement are
hereby waived, released and superseded in their entirety and shall have no further force or effect, including, without limitation, all rights to future stock issuances and any notice period under Section 4 of the Prior Agreement applicable to
the transactions contemplated by the Purchase Agreement. 
 1.2 Definitions. For purposes of this Agreement: 

(a) “Affiliate” means, (i) 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, director or trustee of such Person, or any venture capital or other investment 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, and (ii) with respect to
an Investor, any Person directly or indirectly managed or advised by the Investor or an entity referred to in (i) above. 












 (b) “Board of Directors” means the board of directors of the
Company. 
 (c) “Certificate of Incorporation” means the Company’s Amended and Restated Certificate of
Incorporation, as amended and/or restated from time to time. 
 (d) “Common Stock” means shares of the
Company’s common stock, par value $0.0001 per share. 
 (e) “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 drug development, but shall not include any financial investment firm or
collective investment vehicle that, together with its Affiliates, holds less than 20% of the outstanding equity of any Competitor and does not, nor do any of its Affiliates, have a right to designate any members of the board of directors of any
Competitor. 
 (f) “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: (i) 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; (ii) 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 (iii) 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. 

(g) “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. 
 (h) “Exchange Act” means the
Securities Exchange Act of 1934, as amended, and the rules and regulations promulgated thereunder. 
 (i) “Excluded
Registration” means (i) a registration relating to the sale or grant of securities to employees of the Company or a subsidiary pursuant to a stock option, stock purchase, equity incentive or similar plan; (ii) a registration
relating to an SEC Rule 145 transaction; (iii) 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 (iv) a registration in which the only Common Stock being registered is Common Stock issuable upon conversion of debt securities that are also being registered. 

(j) “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. 

(k) “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. 

  
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 (l) “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 forward incorporation of substantial information by reference to other documents filed
by the Company with the SEC. 
 (m) “GAAP” means generally accepted accounting principles in the United States as in
effect from time to time. 
 (n) “Holder” means any holder of Registrable Securities who is a party to this
Agreement. 
 (o) “Immediate Family Member” means a child, stepchild, grandchild, parent, stepparent, grandparent,
spouse, domestic partner, 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. 
 (p) “Initiating Holders” means, collectively, Holders who properly initiate a registration
request under this Agreement. 
 (q) “IPO” means the Company’s first underwritten public offering of its Common
Stock under the Securities Act. 
 (r) “Key Employee” means any executive-level employee (including division
director and vice president-level positions) as well as any employee or consultant who either alone or in concert with others develops, invents, programs or designs any Company Intellectual Property. 

(s) “Major Investor” means any Investor that, individually or together with such Investor’s Affiliates, holds at
least 2,412,000 shares of Series A Preferred Stock and/or 1,526,717 shares of Series B Preferred Stock (as adjusted for any stock split, stock dividend, combination, or other recapitalization or reclassification effected after the date hereof). 

(t) “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. 

(u) “Person” means any individual, corporation, partnership, trust, limited liability company, association or other
entity. 
 (v) “Preferred Stock” means, collectively, shares of Series A Preferred Stock and Series B Preferred
Stock. 
 (w) “Registrable Securities” means (i) the Common Stock issuable or issued upon conversion of the
Preferred Stock; (ii) 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 (iii) 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
clause (i) 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 Section 6.1, and excluding for purposes of
Section 2 any shares for which registration rights have terminated pursuant to Section 2.13 of this Agreement. 

  
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 (x) “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. 
 (y) “Restricted Securities” means the securities of the Company required to be
notated with the legend set forth in Section 2.12(b) hereof. 
 (z) “SEC” means the Securities and Exchange
Commission. 
 (aa) “SEC Rule 144” means Rule 144 promulgated by the SEC under the Securities Act. 

(bb) “SEC Rule 145” means Rule 145 promulgated by the SEC under the Securities Act. 

(cc) “Securities Act” means the Securities Act of 1933, as amended, and the rules and regulations promulgated
thereunder. 
 (dd) “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 Section 2.6. 

(ee) “Series A Preferred Stock” means shares of the Company’s Series A Preferred Stock, par value $0.0001 per
share. 
 (ff) “Series B Preferred Stock” means shares of the Company’s Series B Preferred Stock, par value
$0.0001 per share. 
 (gg) “Series Preferred Directors” means the directors of the Company that the holders of
record of each of the Series A Preferred Stock and Series B Preferred Stock are entitled to elect, in each case exclusively and as a separate class, pursuant to the Certificate of Incorporation. 

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) five 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 at least 50% of the Registrable Securities then outstanding that the Company file a Form S-1 registration statement with respect to at least 40% of the Registrable Securities then outstanding covering the registration of Registrable Securities with an anticipated aggregate offering price, net of Selling
Expenses, of at least $10 million, 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 Sections 2.1(c) and 2.3. 

  
 4. 













 (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 $3 million, 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 Sections 2.1(c) and 2.3. 

(c) Notwithstanding the foregoing obligations, if the Company furnishes to Holders requesting a registration pursuant to this
Section 2.1 a certificate signed by the Company’s chief executive officer or executive chairperson stating that in the good faith judgment of the 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 it would be materially detrimental to the Company and its stockholders for
such registration statement to be filed and it is therefore necessary to defer the filing of such registration statement, 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. 
 (d) The Company shall not be obligated to effect, or to take any action to effect, any registration pursuant to
Section 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 one registration pursuant to Section 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 Section 2.1(b). The
Company shall not be obligated to effect, or to take any action to effect, any registration pursuant to Section 2.1(b) (i) 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 (ii) if the Company has effected two registrations pursuant to Section 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
Section 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 Section 2.6, in which case such withdrawn registration statement shall be counted as “effected” for purposes of this Section 2.1(d); provided, that if
such withdrawal is during a period the Company has deferred taking action pursuant to Section 2.1(c), then the Initiating Holders may withdraw their request for registration and such registration will not be counted as “effected” for
purposes of this Section 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 securities 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 

  
 5. 













 
Company, the Company shall, subject to the provisions of Section 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 Section 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 Section 2.6. 

2.3 Underwriting Requirements. 

(a) If, pursuant to Section 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 Section 2.1, and the Company shall include such information in the Demand Notice. The underwriter(s) will be selected by the Company and
shall be reasonably acceptable to a majority in interest of the Initiating Holders. In such event, the right of any Holder to include such 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 Section 2.4(e)) enter into an underwriting agreement in customary form with the underwriter(s) selected for such underwriting; provided, however, that no Holder (or any of their assignees) shall be required to
make any representations, warranties or indemnities except as they relate to such Holder’s ownership of shares and authority to enter into the underwriting agreement and to such Holder’s intended method of distribution, and the liability
of such Holder shall be limited to an amount equal to the net proceeds from the offering received by such Holder. Notwithstanding any other provision of this Section 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 Section 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 

  
 6. 













 
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 20% 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 Section 2.3(b) 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 Section 2.1, a registration shall not be counted as “effected” if, as a result of an
exercise of the underwriter’s cutback provisions in Section 2.3(a), fewer 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 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; 

(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; 

  
 7. 













 (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 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, not to exceed $50,000, 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 Section 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 Sections 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 

  
 8. 













 
required to pay any of such expenses and shall not forfeit their right to one registration pursuant to Sections 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. 

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, accountants and investment advisers 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
Section 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 Section 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 Section 2.8(b) and 2.8(d) 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 Section 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 Section 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


  
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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 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. The failure to give notice to the
indemnifying party within a reasonable time of the commencement of any such action shall relieve such indemnifying party of any liability to the indemnified party under this Section 2.8, to the extent that such failure materially prejudices the
indemnifying party’s ability to defend such action. The failure to give notice to the indemnifying party will not relieve it of any liability that it may have to any indemnified party otherwise than under this Section 2.8. 

(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 Section 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 Section 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 Section 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 Section 2.8(d), when combined with the amounts paid or payable by such Holder pursuant to Section 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 Section 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 

  
 10. 













 
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; 
 (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); and (ii) 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 majority of the Registrable Securities then outstanding, enter into any agreement with any holder or prospective holder of any securities of the Company that would (i) provide to such holder or
prospective 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 include such securities in any registration unless, under the terms of such agreement, such holder or
prospective holder may include such securities in any such registration only to the extent that the inclusion of such securities will not reduce the number of the Registrable Securities of the Holders that are included; provided that this
limitation shall not apply to Registrable Securities acquired by any additional Investor that becomes a party to this Agreement in accordance with Section 6.9. 

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 the IPO, and ending on the date specified by the Company and the managing
underwriter (such period not to exceed 180 days), (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 held immediately before the effective date of the registration
statement for the IPO 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 Section 2.11 shall apply only to the IPO, shall not apply to transactions (including, without
limitation, any swap, hedge or similar agreement or arrangement), in each case, relating to securities acquired in the IPO (other than restricting disclosure regarding the same) or securities acquired in open market or other transactions from and
after the IPO or that otherwise that do not involve or relate to shares of Common Stock owned by a Holder prior to the IPO, shall not apply to the sale of any shares to an underwriter pursuant 

  
 11. 













 
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 Member 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 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 1% 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 Section 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 Section 2.11 or that are necessary to give further effect thereto. To the extent that any person who is subject to market stand-off obligations is released early by the managing
underwriter from such market stand-off obligations, then each Holder shall also receive a pro rata release, based on the number of shares subject to such agreements, from their respective market stand-off obligations.
 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. Notwithstanding the foregoing, the Company shall not require any transferee of shares pursuant to an effective registration statement or, following the IPO, SEC Rule 144 to be bound by
the terms of 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 Section 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, AS AMENDED.
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 Section 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 

  
 12. 













 
Securities Act covering the proposed transaction or, following the IPO, the transfer is made pursuant to SEC Rule 144, 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 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 advance notice, 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 for no consideration; provided that, other than in connection with a transaction in compliance with SEC Rule 144 following the IPO, each transferee agrees in writing to be subject to the terms of this
Section 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 or pursuant to an effective
registration statement, the appropriate restrictive legend set forth in Section 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 Sections 2.1 or 2.2 shall terminate upon the earliest to occur of: 

(a) the closing of a Deemed Liquidation Event, as such term is defined in the Certificate of Incorporation in which the consideration
received by the Investors in such Deemed Liquidation Event is in the form of cash and/or publicly traded securities, or if the Investors receive registration rights from the acquiring company or other successor to the Company reasonably comparable
to those set forth in this Section 2; 
 (b) such time after consummation of the IPO as Rule 144 or another similar exemption
under the Securities Act is available for the sale of all of such Holder’s shares without limitation during a three-month period without registration; or 

(c) the fifth anniversary of the date of this Agreement. 

3. Information Rights. 

3.1 Delivery of Financial Statements. The Company shall deliver to each Major Investor, provided that the Board of
Directors has not reasonably determined that such Major Investor is a Competitor of the Company: 
 (a) as soon as practicable, but
in any event within 180 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 (iii) a statement of stockholders’
equity as of the end of such year, all such financial statements audited and certified by independent public accountants of regionally recognized 

  
 13. 













 
standing selected by the Company, unless such requirement is waived by the Board of Directors, including at least one of the Series Preferred Directors; 

(b) as soon as practicable, but in any event within 45 days after the end of each quarter of each fiscal year of the Company, unaudited
statements of income and cash flows for such fiscal quarter, and 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 (i) be subject to normal year-end audit adjustments; and (ii) not contain all notes thereto that may be required in accordance with GAAP); 

(c) if requested, but no more frequently than once a quarter, a statement showing the number of shares of each class and series of
capital stock and securities convertible into or exercisable for shares of capital stock outstanding at the end of the period, the Common Stock issuable upon conversion or exercise of any outstanding securities convertible or exercisable for Common
Stock and the exchange ratio or exercise price applicable thereto, and the number of shares of issued stock options and stock options not yet issued but reserved for issuance, if any, all in sufficient detail as to permit the Major Investors to
calculate their respective percentage equity ownership in the Company, and certified by the chief financial officer, chief executive officer or executive chairperson of the Company as being true, complete, and correct; 

(d) 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 approved by the Board of Directors (collectively, the “Budget”), 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; and 
 (e) such other information relating to the financial condition, business,
prospects, or corporate affairs of the Company as any Major Investor may from time to time reasonably request; provided, however, that the Company shall not be obligated under this Section 3.1 to provide information (i) that the
Company reasonably determines in good faith to be a trade secret or confidential information (unless covered by an enforceable confidentiality agreement, in a form acceptable to the Company); or (ii) the disclosure of which would adversely
affect the attorney-client privilege between the Company and its counsel. 
 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 Section 3.1 to the contrary, the Company may cease providing the
information set forth in this Section 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 Section 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, provided that the Board of Directors has not reasonably determined that such Major Investor is a Competitor of the Company, 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 

  
 14. 













 
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 Section 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) or the disclosure of
which would adversely affect the attorney-client privilege between the Company and its counsel. 
 3.3 Observer Rights. As long
as RA Capital Healthcare Fund, L.P. (“RA Capital”), together with its Affiliates, owns not less than 50% of the shares of the Series B Preferred Stock that RA Capital, together with its Affiliates, purchases under the Purchase
Agreement (or an equivalent amount 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 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 access to 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. 

3.4 Termination of Information and Observer Rights. The covenants set forth in Section 3.1 Section 3.2 and
Section 3.3 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 the closing of a Deemed Liquidation Event, as such term is defined in the Certificate of Incorporation, whichever event occurs first. 

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 Section 3.5 by such Investor), (b) is or has been independently developed or conceived by such Investor
without use of the Company’s confidential information, or (c) is or has been made known or disclosed to such 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 Section 3.5, provided that the Board of
Directors has not reasonably determined that such prospective purchaser is a Competitor of the Company; (iii) to any existing or prospective Affiliate, partner (or partner of a 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; (iv) to the extent required
in connection with any routine or periodic examination or similar process by any regulatory or self-regulatory body or authority not specifically directed at the Company or the confidential information obtained from the Company pursuant to the terms
of the Agreement, including, without limitation, quarterly or annual reports; or (v) as may otherwise be required by law, regulation, rule, court order or subpoena, provided that, with respect to this clause (v), such Investor promptly
notifies the Company of such disclosure and takes reasonable steps to minimize the extent of any such required disclosure. Notwithstanding the foregoing, in the case of any Investor that is (i) a registered investment company within the meaning
of the Investment Company Act of 1940, as amended, or (ii) is advised by a registered investment adviser or Affiliates thereof, 

  
 15. 













 
such Investor may identify the Company and the value of such Investor’s security holdings in the Company in accordance with applicable investment reporting and disclosure regulations or
internal policies and respond to routine examinations, demands, requests or reporting requirements of a regulator without prior notice to or consent from the Company. 

4. Rights to Future Stock Issuances. 

4.1 Right of First Offer. Subject to the terms and conditions of this Section 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 (i) itself, (ii) its Affiliates and (iii) 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 (x) is not a Competitor or
FOIA Party, unless such party’s purchase of New Securities is otherwise consented to by the Board of Directors, (y) agrees to enter into this Agreement and each of the Voting Agreement and Right of First Refusal and Co-Sale Agreement of even date herewith among 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 Sections 3.1, 3.2 and 4.1 hereof), and (z) 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
outstanding (assuming full conversion and/or exercise, as applicable, of all Preferred Stock and any other Derivative Securities then outstanding). 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 Section 4.1(b) shall occur within the later of 90 days of the date that the Offer Notice is given
and the date of initial sale of New Securities pursuant to Section 4.1(c). 

  
 16. 













 (c) If all New Securities referred to in the Offer Notice are not elected to be
purchased or acquired as provided in Section 4.1(b), the Company may, during the 90 day period following the expiration of the periods provided in Section 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
Section 4.1. 
 (d) In the event that the rights of a Major Investor to purchase New Securities under this Section 4.1 are
waived with respect to a particular offering of New Securities without such Major Investor’s prior written consent (a “Waived Investor”) and any Major Investor that participated in waiving such rights actually purchases New
Securities in such offering, then the Company shall grant, and hereby grants, each Waived Investor the right to purchase, in a subsequent closing of such issuance on substantially the same terms and conditions, the same percentage of its full pro
rata share of such New Securities as the highest percentage of any such purchasing Major Investor. 
 (e) The right of first offer in
this Section 4.1 shall not be applicable to (i) Exempted Securities (as defined in the Certificate of Incorporation); and (ii) shares of Common Stock issued in the IPO. 

4.2 Termination. The covenants set forth in Section 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 the closing of a Deemed
Liquidation Event, as such term is defined in the Certificate of Incorporation, whichever event occurs first. 
 5. Additional
Covenants. 
 5.1 Insurance. The Company has obtained 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, and will use commercially reasonable efforts to cause such insurance policies to be maintained until such time as the Board of Directors determines
that such insurance should be discontinued. The policy will not be cancelable by the Company without prior approval by the Board of Directors. Notwithstanding any other provision of this Section 5.1 to the contrary, for so long as at least one
Series Preferred Director 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 $3 million unless approved by at least one Series Preferred
Director, and the Company shall annually, within 120 days after the end of each fiscal year of the Company, deliver to the Major Investors a certification that such a Directors and Officers liability insurance policy remains in effect. 

5.2 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, substantially in the form approved by the
Board of Directors. 
 5.3 Employee Stock. Unless otherwise approved by the Board of Directors, including at least one of the
Series Preferred 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 

  
 17. 













 
date hereof shall be required to execute restricted stock or option agreements, as applicable, providing for (i) 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 (ii) a market stand-off provision
substantially similar to that in Section 2.11. Without the prior approval by the Board of Directors, the Company shall not amend, modify, terminate, waive or otherwise alter, in whole or in part, any stock purchase, stock restriction or option
agreement with any existing employee or service provider if such amendment would cause it to be inconsistent with this Section 5.3. In addition, unless otherwise approved by the Board of Directors, the Company shall retain (and not waive) a
“right of first refusal” on employee transfers until the IPO and shall have the right to repurchase unvested shares at cost upon termination of employment of a holder of restricted stock. 

5.4 Board Matters. Unless otherwise determined by the vote of a majority of the directors then in office, the Board of Directors
shall meet in accordance with an agreed-upon schedule. The Company shall reimburse the 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. 
 5.5 Indemnification;
Successor Indemnification. The Company shall use its best efforts to provide that its Restated Certificate and bylaws provide for indemnification of officers and directors of the Company to the maximum extent permitted by law. The Company
shall enter into a customary indemnification agreement in form satisfactory to the Investors with each non-employee member of the Board of Directors. 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, the Certificate
of Incorporation, or elsewhere, as the case may be. 
 5.6 Publicity. The Company shall not use, publish, reproduce or
refer to the name of any of the Investors, their Affiliates and/or controlling Persons (including any similar name, trademark or logo) in any non-internal discussion, publication, marketing materials or
otherwise to the general public, in each case without the prior written consent of such Investor, which consent may be withheld in its sole discretion; provided that (A) (i) the parties anticipate that there will be a
mutually-agreed press release announcing the closing of the transactions contemplated in the Purchase Agreement in a form that has been previously approved by the Investors and (ii) following the public announcement contemplated in clause (i),
the Company may confirm that the Investors are investors in the Company (but not the amount or terms thereof) in a form of disclosure that has been previously approved by such Investors, which approval shall not be unreasonably withheld, which shall
include naming the Investors on the Company’s website, and (B) nothing herein shall restrict in any way the Company’s ability to file a Form D with the SEC or to file any other required securities filings in connection with the
transactions contemplated by the Purchase Agreement. 
 5.7 Change in Technologies. 

(a) The Company shall promptly notify each Major Investor at any time that (i) the Company begins to produce, design, test,
manufacture, fabricate, or develop one or more “critical technologies” within the meaning of Section 721 of the Defense Production Act of 1950, as amended, including all implementing regulations thereof (the “DPA”) or
(ii) any pre-existing products or services provided by the Company are re-categorized by the U.S. government as a critical technology within the meaning of the DPA
or would reasonably be considered to constitute the design, fabrication, development, testing, production or manufacture of a critical technology after a re-categorization of selected technologies by the U.S.
government. 

  
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 (b) If and only if (i) the Committee on Foreign Investment in the United States
or any member agency thereof acting in its capacity as a member agency (“CFIUS”) requests or requires that the Company or an Investor that is a “foreign person” within the meaning of the DPA file a notice or declaration
with CFIUS pursuant to the DPA, with respect to such Investor’s investment in the Company over which CFIUS has jurisdiction (the “Covered Transaction”), or (ii) the Company and an Investor that is a “foreign
person” within the meaning of the DPA (each of the Investors described in (i) and (ii) a “Non-U.S. Investor”) determine in good faith that a filing with CFIUS with respect to the
Covered Transaction is advisable or required by applicable law, then in either case, (i) or (ii): (x) the Company and such Non-U.S. Investor shall, and shall cause any affiliates to, cooperate and
promptly make a CFIUS filing in the requested, required or advisable form in accordance with the DPA; and (y) the Company and such Non-U.S. Investors shall, and shall cause any affiliates to, use
commercially reasonable efforts to obtain, as applicable, the CFIUS Satisfied Condition. For the avoidance of doubt, a Non-U.S. Investor shall have no obligation to accept or take any action, condition or
restriction with respect to the Covered Transactions in order to achieve the CFIUS Satisfied Condition. The “CFIUS Satisfied Condition” shall be achieved when (a) the Company and the
Non-U.S. Investor shall have received written notice from CFIUS stating that: (i) CFIUS has concluded that the Covered Transactions do not constitute a “covered transaction” subject to review
under the DPA; or (ii) the assessment, review or investigation of the Covered Transactions under the DPA has concluded, and there are no unresolved national security concerns with respect to the Covered Transaction; (b) CFIUS has sent a
report to the President of the United States requesting the President’s decision with respect to the Covered Transactions and either (i) the fifteen day period under the DPA subsequent to the President’s receipt of the CFIUS report
during which the President may announce his decision to take action to suspend, prohibit or place any limitations on the Covered Transaction has expired without any such action being taken or (ii) the President of the United States has
announced a decision not to take any action to suspend, prohibit or place any limitations on the Covered Transactions; or (c) CFIUS has provided written notice that it is not able to complete action under the DPA with respect to the Covered
Transaction on the basis of a CFIUS declaration, but CFIUS has not requested that the Company and the Non-U.S. Investor submit a CFIUS notice and has not initiated a unilateral CFIUS review. 

5.8 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 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. 

  
 19. 













 5.9 Right to Conduct Activities. The Company hereby agrees and acknowledges that
certain of the Investors are professional investment funds (the “Fund Investors”), and as such invest in numerous portfolio companies, some of which may be deemed competitive with the Company’s business (as currently conducted
or as currently proposed to be conducted), and that the Fund Investors each have affiliated entities that may be deemed competitive with the Company’s business (as currently conducted or as currently proposed to be conducted). The Company
hereby agrees that no Fund Investor shall be liable to the Company for any claim arising out of, or based upon, (i) the investment by such Fund Investor in any entity competitive with the Company, (ii) actions taken by any partner, officer
or other representative of such Fund Investor 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 or (iii) the activities of entities affiliated with such Fund Investor; provided, however, that the foregoing shall not relieve (x) any of the Fund Investors from liability associated with
the unauthorized disclosure of the Company’s confidential information obtained pursuant to this Agreement, or (y) any director or officer of the Company from any liability associated with his or her fiduciary duties to the Company. 

5.10 Expenses of Counsel. In the event of a transaction which is a Sale of the Company (as defined in the Voting Agreement), the
reasonable fees and disbursements, not to exceed $50,000 in the aggregate, of one counsel for the Major Investors (“Investor Counsel”) in their capacities as stockholders, shall be borne and paid by the Company. 

5.11 Termination of Covenants. The covenants set forth in this Section 5, except for Sections 5.5 and 5.6, 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 Certificate of Incorporation, whichever event occurs first. 
 6.
Miscellaneous. 
 6.1 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 (i) is an Affiliate of a Holder; (ii) 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 (iii) after such transfer, holds at least 12,500 shares of Registrable Securities (subject to appropriate adjustment for stock splits, stock dividends, combinations, and other recapitalizations);
provided, however, that (x) 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 (y) 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 Section 2.11. For the purposes of
determining the number of shares of Registrable Securities held by a transferee, the holdings of a transferee (1) that is an Affiliate or stockholder of a Holder; (2) who is a Holder’s Immediate Family Member; or (3) 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, as a condition to the applicable transfer, establish 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. 

  
 20. 













 6.2 Governing Law. This Agreement shall be governed by the internal law of the
State of Delaware, without regard to conflict of law principles that would result in the application of any law other than the law of the State of Delaware. 

6.3 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, the Uniform Electronic
Transactions Act or other applicable law) 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. 

6.4 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. 
 6.5 Notices. 

(a) 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 (i) personal delivery to the party to be notified; (ii) 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; (iii) five days after having been sent by registered or certified mail, return receipt requested, postage prepaid; or (iv) one business day after the business day of deposit
with a nationally recognized overnight 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 Section 6.5. If notice is given to the Company, it shall be sent to 991C Lomas Santa Fe #436, Solana Beach, California 92075, Attention: Joao Siffert, M.D.; and a copy (which shall
not constitute notice) shall also be sent to Cooley LLP, 4401 Eastgate Mall, San Diego, CA 92121-1909, Attention: Kenneth J. Rollins, and if notice is given to Investors, a copy (which shall not constitute notice) shall also be given to
Wilson Sonsini Goodrich & Rosati, 12235 El Camino Real, San Diego, CA 92130-3002, Attention: Dan Koeppen. 
 (b) Consent
to Electronic Notice. Each Investor consents to the delivery of any stockholder notice pursuant to the Delaware General Corporation Law (the “DGCL”), as amended or superseded from time to time, by electronic transmission
pursuant to Section 232 of the DGCL (or any successor thereto) at the electronic mail address or the facsimile number set forth below such Investor’s name on the Schedules hereto, as updated from time to time by notice to the Company, or
as on the books of the Company. Each Investor agrees to promptly notify the Company of any change in such stockholder’s electronic mail address, and that failure to do so shall not affect the foregoing. 

6.6 Amendments and Waivers. Any term of this Agreement may be amended, modified or terminated 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 holders of a majority of the Registrable Securities then outstanding;
provided that the Company may in its sole discretion waive compliance with Section 2.12(c) (and the Company’s failure to object promptly in writing after notification of a proposed assignment allegedly in violation of
Section 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, modified 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


  
 21. 













 
such amendment, modification, termination, or waiver applies to all Investors in the same fashion (it being agreed that 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) except as provided in Section 4.1(d), an amendment, modification, termination to or waiver of Sections 3.1 and 3.2, Section 4, Section 5.7 and any other section of this Agreement applicable to the Major Investors (including this
clause (b) of this Section 6.6) shall require only the written consent of the Company and the holders of a majority of the Registrable Securities then outstanding and held by the Major Investors; (c) Section 3.4 may not be
amended, modified, terminated or waived without the written consent of RA Capital; and (d) the definition of “Major Investor” may not be amended in a manner to make an Investor fail to continue to be a Major Investor without such
Investor’s consent. Notwithstanding the foregoing, Schedule A hereto may be amended by the Company from time to time to add transferees of any Registrable Securities in compliance with the terms of this Agreement without the consent of
the other parties; and Schedule A hereto may also be amended by the Company after the date of this Agreement without the consent of the other parties to add information regarding any additional Investor who becomes a party to this Agreement
in accordance with Section 6.9. The Company shall give prompt notice of any amendment, modification or termination hereof or waiver hereunder to any party hereto that did not consent in writing to such amendment, modification, termination, or
waiver. Any amendment, modification, termination, or waiver effected in accordance with this Section 6.6 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. 

6.7 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 shall be reformed and construed so that it will
be valid, legal, and enforceable to the maximum extent permitted by law. 
 6.8 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 Affiliates may apportion such rights as among themselves in any manner they deem
appropriate. 
 6.9 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, 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. 
 6.10 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. 
 6.11 Dispute Resolution. Any unresolved
controversy or claim arising out of or relating to this Agreement, except as (i) otherwise provided in this Agreement, or (ii) any such controversies or claims arising out of either party’s intellectual property rights for which a
provisional remedy or equitable relief is sought, shall be submitted to arbitration by one arbitrator mutually agreed upon by the parties, and 

  
 22. 













 
if no agreement can be reached within 30 days after names of potential arbitrators have been proposed by the American Arbitration Association (the “AAA”), then by one arbitrator
having reasonable experience in corporate finance transactions of the type provided for in this Agreement and who is chosen by the AAA. The arbitration shall take place in San Diego, California, in accordance with the AAA rules then in effect, and
judgment upon any award rendered in such arbitration will be binding and may be entered in any court having jurisdiction thereof. There shall be limited discovery prior to the arbitration hearing as follows: (a) exchange of witness lists and
copies of documentary evidence and documents relating to or arising out of the issues to be arbitrated, (b) depositions of all party witnesses and (c) such other depositions as may be allowed by the arbitrators upon a showing of good
cause. Depositions shall be conducted in accordance with the California Code of Civil Procedure, the arbitrator shall be required to provide in writing to the parties the basis for the award or order of such arbitrator, and a court reporter shall
record all hearings, with such record constituting the official transcript of such proceedings. 
 Each party will bear its own costs in
respect of any disputes arising under this Agreement. Each of the parties to this Agreement consents to personal jurisdiction for any equitable action sought in the U.S. District Court for the Southern District of California or any court of the
State of California having subject matter jurisdiction. 
 6.12 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. 

[Remainder of page intentionally left blank] 

  
 23. 













 The parties have executed this Amended and Restated Investors’ Rights Agreement as of
the date first written above. 
  

					
	COMPANY: 
	
	DESIGN THERAPEUTICS, INC. 
		
	By:	 	/s/ Joao Siffert, M.D.
		 	Name:	 	Joao Siffert, M.D.
		 	Title:	 	President and Chief Executive Officer


 Signature Page to Amended and Restated Investors’ Rights Agreement 












 The parties have executed this Amended and Restated Investors’ Rights Agreement as of
the date first written above. 
  

			
	INVESTOR:
	
	LOGOS OPPORTUNITIES FUND II, L.P.
	 By: Logos Opportunities GP, LLC
 Its
General Partner
  

	By:	 	 /s/ Graham Walmsley 

	Name:	 	Graham Walmsley
	Title:	 	Managing Member
		
	Address:	 	1 Letter Drive
		 	 Building D, Suite D3-700

San Francisco, CA 94129



  

			
	By:	 	 /s/ Arsani William

	Name:	 	Arsani William
	Title:	 	Managing Partner
		
	Address:	 	1 Letterman Drive
		 	Building D, Suite D3-700
		 	San Francisco, CA 94129


 Signature Page to Amended and Restated Investors’ Rights Agreement 












 The parties have executed this Amended and Restated Investors’ Rights Agreement as of
the date first written above. 
  

			
	INVESTOR:
	
	LOGOS SPV 1 LP
	By: Logos Opportunities GP, LLC
	Its General Partner
		
	By:	 	/s/ Graham Walmsley
	Name:	 	Graham Walmsley
	Title:	 	Managing Member


  

			
	Address:	 	1 Letterman Drive
		 	Building D, Suite D3-700
		 	San Francisco, CA 94129


  

			
	By:	 	 /s/ Arsani William

	Name:	 	Arsani William
	Title:	 	Managing Partner


  

			
	Address:	 	1 Letterman Drive
		 	Building D, Suite D3-700
		 	San Francisco, CA 94129


 Signature Page to Amended and Restated Investors’ Rights Agreement 












 The parties have executed this Amended and Restated Investors’ Rights Agreement as of
the date first written above. 
  

			
	INVESTOR:
	
	SR One Capital Fund I Aggregator, L.P.
	
	By: SR One Capital Partners I, LP
	Its: General Partner
	
	By: SR One Capital Management, LLC
	Its: General Partner
		
	By:	 	/s/ Simeon J. George
	Name:	 	Simeon J. George
	Title:	 	Member


 Signature Page to Amended and Restated Investors’ Rights Agreement 












 The parties have executed this Amended and Restated Investors’ Rights Agreement as of
the date first written above. 
  

					
	INVESTOR:
	
	Cormorant Private Healthcare Fund III, LP
	
	By: Cormorant Private Healthcare GP III, LLC
		
	By:	 	 /s/ Bihua Chen

		 	Name:	 	Bihua Chen
		 	Title:	 	Managing Member


 Signature Page to Amended and Restated Investors’ Rights Agreement 












 The parties have executed this Amended and Restated Investors’ Rights Agreement as of
the date first written above. 
  

					
	INVESTOR:
	
	Cormorant Global Healthcare Master Fund, LP
	
	By: Cormorant Global Healthcare GP, LLC
		
	By:	 	 /s/ Bihua Chen

		 	Name:	 	Bihua Chen
		 	Title:	 	Managing Member


 Signature Page to Amended and Restated Investors’ Rights Agreement 












 The parties have executed this Amended and Restated Investors’ Rights Agreement as of
the date first written above. 
  

					
	INVESTOR:
	
	CRMA SPV, L.P.
	
	By: Cormorant Asset Management, LP
		
	By:	 	 /s/ Bihua Chen

		 	Name:	 	Bihua Chen
		 	Title:	 	Attorney-in-fact


 Signature Page to Amended and Restated Investors’ Rights Agreement 












 The parties have executed this Amended and Restated Investors’ Rights Agreement as of
the date first written above. 
  

					
	INVESTOR:
	
	 Quan Venture Fund II, L.P.
  

By: Quan Venture Partners II, L.L.C., Its General Partner

		
	By:	 	/s/ Stella Xu
		 	Name:	 	 Stella Xu

		 	Title:	 	Managing Director


 Signature Page to Amended and Restated Investors’ Rights Agreement 












 The parties have executed this Amended and Restated Investors’ Rights Agreement as of
the date first written above. 
  

					
	INVESTOR:
	
	WRG HCD1, LLC
	
	By: WRG HCD1 GP, LLC, Its Manager
		
	By:	 	 /s/ Trent Dawson

		 	Name:	 	Trent Dawson
		 	Title:	 	Chief Financial Officer
	
	WRG Healthcare Fund I, LP
	
	By: WRG Healthcare GP, LLC, Its General Partner
		
	By:	 	 /s/ Trent Dawson 

		 	Name:	 	Trent Dawson
		 	Title:	 	Chief Financial Officer


 Signature Page to Amended and Restated Investors’ Rights Agreement 












 The parties have executed this Amended and Restated Investors’ Rights Agreement as of
the date first written above. 
  

					
	INVESTOR:
	
	Avoro Life Sciences Fund LLC
		
	By:	 	 /s/ Scott Epstein

		 	Name:	 	Scott Epstein
		 	Title:	 	Partner, Chief Financial Officer & Chief Compliance Officer


 Signature Page to Amended and Restated Investors’ Rights Agreement 












 The parties have executed this Amended and Restated Investors’ Rights Agreement as of
the date first written above. 
  

			
	INVESTOR:
	
	Vivo Opportunity Fund, L.P.
	By: Vivo Opportunity, LLC, General Partner
		
	By:	 	 /s/ Gaurav Aggarwal

	Name:	 	Gaurav Aggarwal
	Title:	 	Managing Member


 Signature Page to Amended and Restated Investors’ Rights Agreement 












 The parties have executed this Amended and Restated Investors’ Rights Agreement as of
the date first written above. 
  

			
	INVESTOR:
	
	JMD I Holdings Limited
		
	By:	 	/s/ Colm O’Connell
	Name:	 	Colm O’Connell
	Title:	 	Authorized Signatory


 Signature Page to Amended and Restated Investors’ Rights Agreement 












 The parties have executed this Amended and Restated Investors’ Rights Agreement as of
the date first written above. 
  

			
	INVESTOR:
	
	667, L.P.
	
	BY: BAKER BROS. ADVISORS LP, management company and investment adviser to 667, L.P., pursuant to authority granted to it by Baker Biotech Capital, L.P., general partner to 667, L.P., and not as the general
partner.
		
	By:	 	 /s/ Scott Lessing

	Name:	 	Scott Lessing
	Title:	 	President


 Signature Page to Amended and Restated Investors’ Rights Agreement 












 The parties have executed this Amended and Restated Investors’ Rights Agreement as of
the date first written above. 
  

			
	INVESTOR:
	
	BAKER BROTHERS LIFE SCIENCES, L.P.
	
	By: BAKER BROS. ADVISORS LP, management company and investment adviser to Baker Brothers Life Sciences, L.P ., pursuant to authority granted to it by Baker Brothers Life Sciences Capital, L.P., general
partner to Baker Brothers Life Sciences, L.P., and not as the general partner.
		
	By:	 	 /s/ Scott Lessing

	Name:	 	Scott Lessing
	Title:	 	President


 Signature Page to Amended and Restated Investors’ Rights Agreement 












 The parties have executed this Amended and Restated Investors’ Rights Agreement as of
the date first written above. 
  

			
	INVESTOR:
	
	CITADEL MULTI-STRATEGY EQUITIES MASTER FUND LTD.
	By: Citadel Advisors LLC, its portfolio manager
		
	By:	 	 /s/ Shellane Mulcahy

	Name:	 	Shellane Mulcahy
	Title:	 	Authorized Signatory


 Signature Page to Amended and Restated Investors’ Rights Agreement 












 The parties have executed this Amended and Restated Investors’ Rights Agreement as of
the date first written above. 
  

			
	INVESTOR:
	
	HEALTHCARE INNOVATION INVESTMENT FUND LLC
		
	By:	 	 /s/ Joseph R. Gentile

		 	Name: Joseph R. Gentile
		 	Title: Manager


 Signature Page to Amended and Restated Investors’ Rights Agreement 












 The parties have executed this Amended and Restated Investors’ Rights Agreement as of
the date first written above. 
  

			
	INVESTOR:
	
	RA CAPITAL HEALTHCARE FUND, L.P.
	
	By: RA Capital Healthcare Fund GP, LLC
	Its General Partner
		
	By:	 	 /s/ Rajeev Shah

	Name:	 	Rajeev Shah
	Title:	 	 Manager



 Signature Page to Amended and Restated Investors’ Rights Agreement 












 The parties have executed this Amended and Restated Investors’ Rights Agreement as of
the date first written above. 
  

			
	INVESTOR:
	
	RA Capital NEXUS Fund II, L.P.
	
	By: RA Capital Nexus Fund II GP, LLC
	Its General Partner
		
	By:	 	 /s/ Rajeev Shah

	Name:	 	Rajeev Shah
	Title:	 	Manager


 Signature Page to Amended and Restated Investors’ Rights Agreement 












 The parties have executed this Amended and Restated Investors’ Rights Agreement as of
the date first written above. 
  

			
	INVESTOR:
	
	Wellington Biomedical Innovation Master Investors (Cayman) I L.P.
	
	By: Wellington Management Company LLP, as investment advisor
		
	By:	 	 /s/ Peter N. McIsaac

	Name:	 	Peter N. McIsaac
	Title:	 	Managing Director and Counsel


 Signature Page to Amended and Restated Investors’ Rights Agreement 












 The parties have executed this Amended and Restated Investors’ Rights Agreement as of
the date first written above. 
  

			
	 INVESTOR:
  

GC&H Investments, LLC

		
	By:	 	/s/ Jim Kindler
	Name:	 	Jim Kindler
	Title:	 	Manager


 Signature Page to Amended and Restated Investors’ Rights Agreement 












 The parties have executed this Amended and Restated Investors’ Rights Agreement as of
the date first written above. 
  

			
	INVESTOR:
	
	WS Investments, LLC (20A)


 
			
		
	By:	 	 /s/ Dan Koeppen



 
			
	Name: Dan Koeppen
	Title: Partner


 Signature Page to Amended and Restated Investors’ Rights Agreement 












 The parties have executed this Amended and Restated Investors’ Rights Agreement as of
the date first written above. 
  

			
	INVESTOR:
	
	BLACKROCK HEALTH SCIENCES TRUST II
	
	By: BlackRock Advisors, LLC, its Investment Adviser


 
			
		
	By:	 	 /s/ Hongying Erin Xie





			
	Name: Hongying Erin Xie
	Title: Managing Director


 Signature Page to Amended and Restated Investors’ Rights Agreement 












 The parties have executed this Amended and Restated Investors’ Rights Agreement as of
the date first written above. 
  

			
	INVESTOR:
	
	JANUS HENDERSON GLOBAL LIFE SCIENCES FUND
	
	By: Janus Capital Management LLC, its investment advisor


 
			
		
	By:	 	 /s/ Andrew Acker



 
			
	Name: Andrew Acker
	Title: Authorized Signatory


 Signature Page to Amended and Restated Investors’ Rights Agreement 












 The parties have executed this Amended and Restated Investors’ Rights Agreement as of
the date first written above. 
  

			
	INVESTOR:
	
	JANUS HENDERSON CAPITAL FUNDS PLC ON BEHALF OF ITS SERIES JANUS HENDERSON GLOBAL LIFE SCIENCES FUND
	
	By: Janus Capital Management LLC, its investment advisor


 
			
		
	By:	 	 /s/ Andrew Acker



 
			
	Name: Andrew Acker
	Title: Authorized Signatory


 Signature Page to Amended and Restated Investors’ Rights Agreement 












 The parties have executed this Amended and Restated Investors’ Rights Agreement as of
the date first written above. 
  

					
	INVESTOR:
	
	T. Rowe Price Health Sciences Fund, Inc.
	TD Mutual Funds—TD Health Sciences Fund
	T. Rowe Price Health Sciences Portfolio
	 Each account, severally and not jointly

	
	By: T. Rowe Price Associates, Inc., Investment Adviser or Subadviser, as applicable


 
					
			
	        	 	By:	 	 /s/ Andrew Baek





					
	        	 	Name: Andrew Baek
		 	Title: Vice President


 Signature Page to Amended and Restated Investors’ Rights Agreement 












 SCHEDULE A 

INVESTORS 
  

			
	 Name
	  	 Address

		
	Logos Opportunities Fund II, L.P.	  	 1 Letterman Drive
 Building D, Suite D3-700
 San Francisco, CA 94129

Attn: Arsani William, M.D.

arsani@logoscapital.com

		
	Logos SPV 1 LP	  	 1 Letterman Drive
 Building D, Suite D3-700
 San Francisco, CA 94129

Attn: Arsani William, M.D.

arsani@logoscapital.com

		
	S.R. One Capital Fund I Aggregator, L.P.	  	 985 Old Eagle School Road
 Suite 511

Wayne, PA 19087

		
	Cormorant Private Healthcare Fund III, LP	  	 200 Clarendon Street, 52nd Floor
 Boston, MA
02116

		
	Cormorant Global Healthcare Master Fund, LP	  	 200 Clarendon Street, 52nd Floor
 Boston, MA
02116

		
	CRMA SPV, L.P.	  	 PO Box 309, Ugland House,
 Grand Cayman; KY1-1104 Cayman Islands

		
	CB Trust dated October 6, 2003	  	 335 Corte Madera Ave,
 Mill Valley, CA
94941

		
	David Rabuka and Jocelyn Sperling Trust	  	 202 Stanford Ave,
 Kensington, CA
94708

		
	GC&H Investments, LLC	  	 101 California Street, 5th Floor,
 San
Francisco, CA 94111 (Attn: Jim Kindler)

		
	Pratik Shah Living Trust (6/15/2011)	  	 991C Lomas Santa Fe Road, #436,
 Solana Beach,
CA 92075

		
	Quan Venture Fund II, L.P.	  	 c/o Quan Capital
 1440 O’Brien Dr, 1/F, Ste
A
 Menlo Park, CA 94025

		
	WRG HCD1, LLC	  	 920 5th Avenue, Suite 3450

Seattle, WA 98104



  
 Schedule A-1 














			
		
	Blackrock Health Sciences Trust II	  	 c/o BlackRock Advisors, LLC
 60 State Street,
19th/20th Floor
 Boston, MA 02109
 Attn: Erin Xie

Email: erin.xie@blackrock.com and

FEPMAssistantsUS@blackrock.com
  

With a copy (which shall not constitute notice) to:

 
 c/o BlackRock, Inc.

Office of the General Counsel

40 East 52nd Street

New York, NY 10022

Attn: David Maryles and Reid Fitzgerald

Email: legaltransactions@blackrock.com

		
	Janus Henderson Global Life Sciences Fund	  	 c/o Janus Capital Management LLC 
 151
Detroit Street
 Denver, CO 80206
 Attn: Andy AckerAttn: Angela
Morton
  

Email:andy.acker@janushenderson.com;

amorton@janushenderson.com
  

with a copy, which shall not constitute notice, to:

 
 Perkins Coie LLP

3150 Porter Drive

Palo Alto, CA 94306

Attn: Adrian Rich (Email: arich@perkinscoie.com)

		
	Janus Henderson Capital Funds Plc-Janus Henderson Global Life Sciences Fund	  	 c/o Janus Capital Management LLC 
 151
Detroit Street
 Denver, CO 80206
 Attn: Andy AckerAttn: Angela
Morton
  
 Email:andy.acker@janushenderson.com;
amorton@janushenderson.com 
  
 with
a copy, which shall not constitute notice, to:
  

Perkins Coie LLP

3150 Porter Drive

Palo Alto, CA 94306

Attn: Adrian Rich (Email:
arich@perkinscoie.com)















			
		
	RA Capital Healthcare Fund, L.P.	  	 RA Capital Management, L.P.
 200 Berkeley
Street
 18th Floor

Boston, BA 02116
 Attn: General Counsel

		
	RA Capital Nexus Fund II, L.P.	  	 RA Capital Management, L.P.
 200 Berkeley
Street
 18th Floor

Boston, BA 02116
 Attn: General Counsel

		
	Baker Brothers Life Sciences, L.P.	  	 860 Washington St, 3rd Floor
 New York, NY
10014

		
	667, L.P.	  	 860 Washington St, 3rd Floor
 New York, NY
10014

		
	Wellington Biomedical Innovation Master Investors (Cayman) I L.P.	  	 c/o Wellington Management Company LLP
 280
Congress Street
 Boston, MA 02210
 ATTN: Private Investment
Services
 Email: PrivateInvestmentServices@wellington.com
  

With a copy (which shall not constitute notice) to:
  

Wilmer Cutler Pickering Hale and Dorr LLP
 60 State Street

Boston, MA 02109
 Attention: Jason L. Kropp

Email: jason.kropp@wilmerhale.com

		
	Avoro Life Sciences Fund LLC	  	 110 Greene Street, Suite 800
 New York, NY
10012

		
	Vivo Opportunity Fund, L.P.	  	 C/O: Vivo Capital LLC
 192 Lytton Avenue, Palo
Alto, CA 94301
 Attn: General Counsel
 E-mail: legal@vivocapital.com
 Telephone: (650) 688-0818

Fax: (650) 688-1815

		
	Healthcare Innovation Investment Fund LLC	  	 Healthcare Innovation Investment Fund LLC
 c/o
SVB Leerink LLC
 One Federal Street, 37th Floor

Boston, MA 02110
 Attention: Steven Heineman

Email: steven.heineman@svbleerink.com















			
		
	WS Investments, LLC (20A)	  	 Attn: James Terranova
 650 Page Mill Rd

Palo Alto, CA 94304

		
	GC&H Investments, LLC	  	 101 California Street, 5th Floor
 San Francisco,
CA 94111
 (Attn: Jim Kindler)

		
	Citadel Multi-Strategy Equities Master Fund Ltd.	  	 c/o Citadel Advisors LLC
 601 Lexington
Avenue
 New York, New York 10022
 Attention: Harry
Greenbaum
 Harry.Greenbaum@citadel.com;

CitadelAgreementNotice@citadel.com;
  

With copies to:
  

Choate, Hall & Stewart, LLP
 Two International Place

Boston, MA 02100
 Attention: Brian P. Lenihan and Tobin P.
Sullivan
 blenihan@choate.com; tsullivan@choate.com

		
	JMD I Holdings Limited	  	 Walkers Corporate Limited, Cayman Corporate Centre

27 Hospital Road, George Town
 Grand Cayman KY1-9008, Cayman Islands

		
	T. Rowe Price Health Sciences Fund, Inc.	  	 T. Rowe Price Associates, Inc.
 100 East Pratt
Street
 Baltimore, MD 21202
 Attn: Andrew Baek, Vice
President
 Phone: 410-345-2090

Email: Andrew.Baek@troweprice.com

		
	TD Mutual Funds—TD Health Sciences Fund	  	 T. Rowe Price Associates, Inc.
 100 East Pratt
Street
 Baltimore, MD 21202
 Attn: Andrew Baek, Vice
President
 Phone: 410-345-2090

Email: Andrew.Baek@troweprice.com

		
	T. Rowe Price Health Sciences Portfolio	  	 T. Rowe Price Associates, Inc.
 100 East Pratt
Street
 Baltimore, MD 21202
 Attn: Andrew Baek, Vice
President
 Phone: 410-345-2090

Email: Andrew.Baek@troweprice.com