Document:

EX-4.2

 Exhibit 4.2 

FOURTH AMENDED AND RESTATED INVESTORS’ RIGHTS AGREEMENT 

 TABLE OF CONTENTS 
  

									
	 	  	 	  	 	  	Page	 
	 1.
	  	Definitions	  	 	1	 
	 2.
	  	Registration Rights	  	 	5	 
		  	2.1	  	Demand Registration	  	 	5	 
		  	2.2	  	Company Registration	  	 	7	 
		  	2.3	  	Underwriting Requirements.	  	 	7	 
		  	2.4	  	Obligations of the Company	  	 	9	 
		  	2.5	  	Furnish Information	  	 	10	 
		  	2.6	  	Expenses of Registration	  	 	10	 
		  	2.7	  	Delay of Registration	  	 	11	 
		  	2.8	  	Indemnification	  	 	11	 
		  	2.9	  	Reports Under Exchange Act	  	 	13	 
		  	2.10	  	Limitations on Subsequent Registration Rights	  	 	14	 
		  	2.11	  	“Market Stand-off’ Agreement	  	 	14	 
		  	2.12	  	Restrictions on Transfer.	  	 	15	 
		  	2.13	  	Termination of Registration Rights	  	 	17	 
	 3.
	  	Information and Observer Rights.	  	 	17	 
		  	3.1	  	Delivery of Financial Statements	  	 	17	 
		  	3.2	  	Inspection	  	 	18	 
		  	3.3	  	Observer Rights.	  	 	18	 
		  	3.4	  	Termination of Information Rights	  	 	19	 
		  	3.5	  	Confidentiality	  	 	19	 
		  	3.6	  	Material Non-Public Information	  	 	20	 
	 4.
	  	Rights to Future Stock Issuances	  	 	20	 
		  	4.1	  	Right of First Offer	  	 	20	 
		  	4.2	  	Termination	  	 	21	 
	 5.
	  	Additional Covenants.	  	 	21	 
		  	5.1	  	Insurance	  	 	21	 
		  	5.2	  	Employee Agreements	  	 	22	 
		  	5.3	  	Employee Stock	  	 	22	 
		  	5.4	  	Matters Requiring Investor Director Approval	  	 	22	 
		  	5.5	  	Board Matters	  	 	23	 
		  	5.6	  	Successor Indemnification	  	 	23	 
		  	5.7	  	Indemnification Matters	  	 	24	 
		  	5.8	  	Qualified Small Business Stock	  	 	24	 
		  	5.9	  	FCPA	  	 	24	 
		  	5.10	  	Publicity	  	 	25	 
		  	5.11	  	Expenses of Counsel	  	 	25	 
		  	5.12	  	Critical Technology Matters	  	 	26	 
		  	5.13	  	Munitions	  	 	26	 
		  	5.14	  	Subsidiary Governance	  	 	26	 
		  	5.15	  	Harassment Policy	  	 	26	 
		  	5.16	  	Termination of Covenants	  	 	27	 

  
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	 6.
	  	Miscellaneous	  	 	27	 
		  	6.1	  	Successors and Assigns	  	 	27	 
		  	6.2	  	 Governing Law
	  	 	27	 
		  	6.3	  	 Counterparts
	  	 	27	 
		  	6.4	  	 Titles and Subtitles
	  	 	27	 
		  	6.5	  	 Notices
	  	 	28	 
		  	6.6	  	 Amendments and Waivers
	  	 	28	 
		  	6.7	  	 Severability
	  	 	29	 
		  	6.8	  	 Aggregation of Stock
	  	 	29	 
		  	6.9	  	 Additional Investors
	  	 	30	 
		  	6.10	  	 Entire Agreement
	  	 	30	 
		  	6.11	  	 Dispute Resolution
	  	 	30	 
		  	6.12	  	 Delays or Omissions
	  	 	31	 
		  	6.13	  	 Right to Conduct Activities
	  	 	31	 
		  	6.14	  	 Limitation of Liability
	  	 	31	 

  

					
	Schedule A	  	—  	  	Schedule of Investors
	Schedule B	  	—  	  	Affiliates of Clarus Lifesciences III, L.P.

  

  
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 THIS FOURTH AMENDED AND RESTATED INVESTORS’ RIGHTS AGREEMENT 

THIS FOURTH AMENDED AND RESTATED INVESTORS’ RIGHTS AGREEMENT (this “Agreement”), is made as of the 24th day of July, 2020, by and among
Praxis Precision Medicines, Inc., a Delaware corporation (the “Company”), and each of the investors listed on Schedule A hereto (together with any subsequent investors or transferees, who become parties to this Agreement in
accordance with Section 6.9 hereof, each an “Investor” and together the “Investors”). 

RECITALS 
 WHEREAS,
certain of the Investors (the “Existing Investors”) hold shares of the Company’s Series A Preferred Stock, Series B Preferred Stock, Series B-1 Preferred Stock, Series C Preferred Stock
and/or shares of Common Stock issued upon conversion thereof and possess registration rights, information rights, rights of first offer, and other rights pursuant to the Third Amended and Restated Investors’ Rights Agreement dated as of
November 18, 2019 between the Company and such Investors (the “Prior Agreement”); and 
 WHEREAS, the Existing
Investors comprise the Investor Majority (as defined in the Prior Agreement), and desire to amend and restate the Prior Agreement in its entirety and to accept the rights and obligations created pursuant to this Agreement in lieu of the rights and
obligations granted to them under the Prior Agreement; and 
 WHEREAS, certain of the Investors are parties to that certain Series C-1 Preferred Stock Purchase Agreement of even date herewith between the Company and certain of the Investors (the “Purchase Agreement”). 

NOW, THEREFORE, the Existing Investors hereby agree that the Prior Agreement shall be amended and restated, and the parties to this
Agreement further agree as follows: 
 1. Definitions. For purposes of this Agreement: 

“Affiliate” means, with respect to any specified Person, any other Person who, directly or indirectly, controls, is controlled
by, or is under common control with such Person, including without limitation any general partner, managing member, officer or director of such Person or any venture capital or other investment fund now or hereafter existing that is controlled by
one or more general partners or managing members or investment advisers of, or shares the same management company or investment adviser with, such Person; the terms “control” and “controlled” meaning ownership of fifty percent
(50%) or more, including ownership by one or more trusts with substantially the same beneficial interests, of the voting and equity rights of such Person or the power to direct the management of such Person. Notwithstanding the foregoing, where the
term “Person” refers to Novo Holdings A/S, in lieu of the foregoing definition, the term “Affiliate” shall mean Novo Ventures (US) Inc., any partner, executive officer or director of Novo or any venture capital fund or
other Person now or hereafter existing formed for the purpose of making investments in other Persons that is controlled by or under common control with Novo, and for the avoidance of doubt, shall not include any other affiliate of Novo. Further
notwithstanding the foregoing, where the term “Person” refers to Clarus, in lieu of the foregoing definition, the term “Affiliate” shall mean (a) any fund or other Person now or hereafter existing 

 
or hereafter formed, in each case, (i) for the purpose of making investments in other Persons and (ii) that is under common management with Clarus, including without limitation any such
fund or Person for which Clarus Ventures LLC provides management services, and (b) any general partner, managing member, officer, managing director or director of Clarus or Clarus Ventures III GP, L.P. or any of the funds listed on Schedule
B or described in the following clause (c), (c) any fund or other Person now or hereafter existing, the management of which is controlled by The Blackstone Group L.P., formed for the purpose of making at least 25% of its investments in other
Persons that are engaged in the research, development, production or distribution of human therapeutic products or services, and (d) any fund or other Person now or hereafter existing formed for the purpose of making investments in other
Persons that is under management of any general partner, managing member, officer, managing director or director of Clarus or Clarus Ventures III GP, L.P. or under management of an entity in which any general partner, managing member, officer,
managing director or director of Clarus or Clarus Ventures III GP, L.P. is a general partner, managing member, officer, managing director or director. For the avoidance of doubt, “Affiliates” of Clarus include those listed on Schedule
B and Schedule B shall be automatically deemed updated to include any new funds under the Blackstone Life Sciences (or its successor) umbrella added in the future. 

“Al-Rayyan” means Al-Rayyan Holding LLC, a Qatar Financial Center registered limited liability company, and for purposes of
Section 5.10, shall include Qatar Investment Authority, their Affiliates and all instrumentalities of the State of Qatar and their associates. 

“Clarus” means Clarus Lifesciences III, L.P. or any transferee, assignee or successor in such stockholder’s interest in
the Company. 
 “Common Stock” means shares of the Company’s common stock, par value $0.0001 per share. 

“Competitor” means a Person engaged, directly or indirectly (including through any partnership, limited liability company,
corporation, joint venture or similar arrangement (whether now existing or formed hereafter)), in the same or similar business as the Company, as reasonably determined by the Board of Directors, but shall not include any financial investment firm,
institutional investor or investment vehicle. Notwithstanding the above, for purposes of Section 4 of this Agreement, Gilead Sciences, Novo Holdings A/S, Novo Ventures (US) Inc., Clarus, Vida, Purdue Neuroscience Company,
Point72 Biotech, OCV, Citadel Multi-Strategy Equities Master Fund Ltd. (“Surveyor”), Al-Rayyan and Eventide and their respective Affiliates shall not be deemed to be a Competitor. 

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

  
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 “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. 

“Eventide” means the Mutual Fund Series Trust, On Behalf Of Eventide Healthcare & Life Sciences Fund or any
transferee, assignee or successor in such stockholder’s interest in the Company. 
 “Exchange Act” means the
Securities Exchange Act of 1934, as amended, and the rules and regulations promulgated thereunder. 
 “Excluded
Registration” means (i) a registration relating to the sale of securities to employees of the Company or a subsidiary pursuant to a stock option, stock purchase, or similar plan; (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. 

“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. 
 “Form
S-3” means such form under the Securities Act as in effect on the date hereof or any registration form under the Securities Act subsequently adopted by the SEC that permits incorporation of
substantial information by reference to other documents filed by the Company with the SEC. 
 “GAAP” means generally
accepted accounting principles in the United States. 
 “Holder” means any holder of Registrable Securities who is a party
to this Agreement. 
 “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. 
 “Initiating Holders” means, collectively, Holders who properly initiate a registration request under
this Agreement. 
 “Investor Majority” means (i) the Investors holding a majority of the then outstanding Series A
Preferred Stock, Series B Preferred Stock, Series B-1 Preferred Stock, Series C Preferred Stock and Series C-1 Preferred Stock (voting together as a single class, and
not as separate series, on an as-converted basis) then held by the Investors and (ii) at least two of the following three Purchasers (as defined in the Purchase Agreement): Clarus, Novo and Vida. 

  
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 “IPO” means the Company’s first underwritten public offering of its
Common Stock under the Securities Act. 
 “Key Employee” means any executive-level employee (including, division director
and vice president-level positions) as well as any employee who, either alone or in concert with others, develops, invents, programs, or designs any Company Intellectual Property (as defined in the Purchase Agreement). 

“Major Investor” means any Investor that, individually or together with such Investor’s Affiliates, holds at least Two
Million (2,000,000) shares of Registrable Securities (as adjusted for any stock split, stock dividend, combination, or other recapitalization or reclassification effected after the date hereof). 

“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. 

“Novo” means Novo Holdings A/S or any transferee, assignee or successor in such stockholder’s interest in the Company.

 “OCV” means OCV Fund I, L.P. or any transferee, assignee or successor in either such stockholders’ interest in the
Company. 
 “Person” means any individual, corporation, partnership, firm, trust, limited liability company, association or
other entity or combination thereof. 
 “Point72 Biotech” means Point72 Biotech Private Investments, LLC or any transferee,
assignee or successor in such stockholder’s interest in the Company. 
 “Preferred Directors” means the directors of
the Company elected solely by the holders of record of either the Series A Preferred Stock or the Series B Preferred Stock and Series B-1 Preferred Stock pursuant to the Company’s Certificate of
Incorporation. 
 “Preferred Stock” means the Series A Preferred Stock, the Series B Preferred Stock, the Series B-1 Preferred Stock, the Series C Preferred Stock and the Series C-1 Preferred Stock. 

“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, held by the Investors as of the date hereof or 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 clauses (i) and (ii) above; excluding in all cases, however, any Registrable Securities sold by a Person in a transaction in which the applicable rights under this Agreement are not assigned pursuant to
Subsection 6.1, and excluding for purposes of Section 2 any shares for which registration rights have terminated pursuant to Subsection 2.13 of this Agreement. 

  
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 “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. 
 “Restricted Securities” means the securities of the Company required to be notated with the
legend set forth in Subsection 2.12(b) hereof. 
 “SEC” means the Securities and Exchange Commission. 

“SEC Rule 144” means Rule 144 promulgated by the SEC under the Securities Act. 

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

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

“Selling Expenses” means all underwriting discounts, selling commissions, and stock transfer taxes applicable to the sale of
Registrable Securities, and fees and disbursements of counsel for any Holder, except for the fees and disbursements of the Selling Holder Counsel borne and paid by the Company as provided in Subsection 2.6. 

“Series A Preferred Stock” means shares of the Company’s Series A Preferred Stock, par value $0.0001 per share. 

“Series B Preferred Stock” means shares of the Company’s Series B Preferred Stock, par value $0.0001 per share. 

“Series B-1 Preferred Stock” means shares of the Company’s Series B-1 Preferred Stock, par value $0.0001 per share. 
 “Series C Preferred Stock” means
shares of the Company’s Series C Preferred Stock, par value $0.0001 per share. 
 “Series
C-1 Preferred Stock” means shares of the Company’s Series C Preferred Stock, par value $0.0001 per share. 

“Vida” means Vida Ventures, LLC or any transferee, assignee or successor in such stockholder’s interest in the Company.

 2. Registration Rights. The Company covenants and agrees as follows: 

2.1 Demand Registration. 

(a) Form S-1 Demand. If at any time after one hundred eighty (180) days after the effective date of the registration
statement for the IPO, the Company receives a request from Holders of a majority of the Registrable Securities then outstanding that the Company file a Form S-1 registration statement with respect to
Registrable Securities having an anticipated 

  
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aggregate offering price, net of Selling Expenses, of at least $10,000,000, then the Company shall (i) within ten (10) days after the date such request is given, give
notice thereof (the “Demand Notice”) to all Holders other than the Initiating Holders; and (ii) as soon as practicable, and in any event within sixty (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 twenty (20) days of the date the Demand Notice is given, and in each case, subject to the limitations of
Subsections 2.1(c) and 2.3. 
 (b) Form S-3 Demand. If at any time when it
is eligible to use a Form S-3 registration statement, the Company receives a request from Holders of a majority 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 $3,000,000, then the Company shall
(i) within ten (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 forty- five
(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 twenty (20) days of the date the Demand Notice is given, and in each case, subject to the limitations of
Subsections 2.1(c) and 2.3. 
 (c) Notwithstanding the foregoing obligations, if the Company furnishes to Holders requesting a
registration pursuant to this Subsection 2.1 a certificate signed by the Company’s chief executive officer stating that in the good faith judgment of the Company’s Board of Directors it would be materially detrimental to the Company
and its stockholders for such registration statement to either become effective or remain effective for as long as such registration statement otherwise would be required to remain effective, because such action would (i) materially interfere
with a significant acquisition, corporate reorganization, or other similar transaction involving the Company; (ii) require premature disclosure of material information that the Company has a bona fide business purpose for preserving as
confidential; or (iii) render the Company unable to comply with requirements under the Securities Act or Exchange Act, then the Company shall have the right to defer taking action with respect to such filing, and any time periods with
respect to filing or effectiveness thereof shall be tolled correspondingly, for a period of not more than one hundred twenty (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 twelve (12) month period; and provided further that the Company shall not register any securities for its own account or that of any other stockholder during such one hundred twenty
(120) day period other than an Excluded Registration. 
 (d) The Company shall not be obligated to effect, or to take any action
to effect, any registration pursuant to Subsection 2.1(a) (i) during the period that is sixty (60) days before the Company’s good faith estimate of the date of filing of, and ending on a date that is one hundred
eighty (180) days after the effective date of, a Company-initiated registration, provided that the Company is actively employing in good faith commercially reasonable efforts to cause such registration statement to become
effective; (ii) after the Company has effected two 

  
 6 

 
registrations pursuant to Subsection 2.1(a); or (iii) if the Initiating Holders propose to dispose of shares of Registrable Securities that may be immediately registered on
Form S-3 pursuant to a request made pursuant to Subsection 2.1(b). The Company shall not be obligated to effect, or to take any action to effect, any registration pursuant to Subsection
2.1(b) (i) during the period that is thirty (30) days before the Company’s good faith estimate of the date of filing of, and ending on a date that is ninety (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 Subsection 2.1(b) within the twelve (12) month period immediately preceding the date of such request. A registration shall not be counted as “effected” for purposes of this Subsection 2.1(d) until
such time as the applicable registration statement has been declared effective by the SEC, unless the Initiating Holders withdraw their request for such registration, elect not to pay the registration expenses therefor, and forfeit their right to
one demand registration statement pursuant to Subsection 2.6, in which case such withdrawn registration statement shall be counted as “effected” for purposes of this Subsection 2.1(d). 

2.2 Company Registration. If the Company proposes to register (including, for this purpose, a registration effected by the Company for
stockholders other than the Holders) any of its 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 twenty (20) days after such notice is given by the Company, the Company shall, subject to the provisions of Subsection 2.3, cause to be registered all
of the Registrable Securities that each such Holder has requested to be included in such registration. The Company shall have the right to terminate or withdraw any registration initiated by it under this Subsection 2.2 before the effective
date of such registration, whether or not any Holder has elected to include Registrable Securities in such registration. The expenses (other than Selling Expenses) of such withdrawn registration shall be borne by the Company in accordance with
Subsection 2.6. 
 2.3 Underwriting Requirements. 

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

  
 7 

 
this Subsection 2.3, if the managing underwriter(s) advise(s) the Initiating Holders in writing that marketing factors require a limitation on the number of shares to be underwritten, then
the Initiating Holders shall so advise all Holders of Registrable Securities that otherwise would be underwritten pursuant hereto, and the number of Registrable Securities that may be included in the underwriting shall be allocated among such
Holders of Registrable Securities, including the Initiating Holders, in proportion (as nearly as practicable) to the number of Registrable Securities owned by each Holder or in such other proportion as shall mutually be agreed to by all such selling
Holders; provided, however, that the number of Registrable Securities held by the Holders to be included in such underwriting shall not be reduced unless all other securities are first entirely excluded from the underwriting. To
facilitate the allocation of shares in accordance with the above provisions, the Company or the underwriters may round the number of shares allocated to any Holder to the nearest one hundred (100) shares. 

(b) In connection with any offering involving an underwriting of shares of the Company’s capital stock pursuant to Subsection 2.2,
the Company shall not be required to include any of the Holders’ Registrable Securities in such underwriting unless the Holders seeking to sell Registrable Securities in such offering accept the terms of the underwriting as agreed upon between
the Company and its underwriters, and then only in such quantity as the underwriters in their sole discretion determine will not jeopardize the success of the offering by the Company. If the total number of securities, including Registrable
Securities, requested by stockholders to be included in such offering exceeds the number of securities to be sold (other than by the Company) that the underwriters in their reasonable discretion determine is compatible with the success of the
offering, then the Company shall be required to include in the offering only that number of such securities, including Registrable Securities, which the underwriters and the Company in their sole discretion determine will not jeopardize the success
of the offering. If the underwriters determine that less than all of the Registrable Securities requested to be registered can be included in such offering, then the Registrable Securities that are included in such offering shall be allocated among
the selling Holders in proportion (as nearly as practicable to) the number of Registrable Securities owned by each selling Holder or in such other proportions as shall mutually be agreed to by all such selling Holders. To facilitate the allocation
of shares in accordance with the above provisions, the Company or the underwriters may round the number of shares allocated to any Holder to the nearest one hundred (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 thirty percent (30%) of the total number of securities included in such offering, unless such offering is the IPO, in which case the selling Holders may be excluded further if the
underwriters make the determination described above and no other stockholder’s securities are included in such offering. For purposes of the provision in this Subsection 2.3(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. 

  
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 (c) For purposes of Subsection 2.1, a registration shall not be counted as
“effected” if, as a result of an exercise of the underwriter’s cutback provisions in Subsection 2.3(a), fewer than fifty percent (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 one hundred
twenty (120) days or, if earlier, until the distribution contemplated in the registration statement has been completed; provided, however, that (i) such one hundred twenty (120) day period shall be
extended for a period of time equal to the period the Holder refrains, at the request of an underwriter of Common Stock (or other securities) of the Company, from selling any securities included in such registration, and (ii) in the case of
any registration of Registrable Securities on Form S-3 that are intended to be offered on a continuous or delayed basis, subject to compliance with applicable SEC rules, such one hundred twenty
(120) day period shall be extended for up to one hundred eighty (180) days, if necessary, to keep the registration statement effective until all such Registrable Securities are sold; 

(b) prepare and file with the SEC such amendments and supplements to such registration statement, and the prospectus used in connection with
such registration statement, as may be necessary to comply with the Securities Act in order to enable the disposition of all securities covered by such registration statement; 

(c) furnish to the selling Holders such numbers of copies of a prospectus, including a preliminary prospectus, as required by the Securities
Act, and such other documents as the Holders may reasonably request in order to facilitate their disposition of their Registrable Securities; 

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

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

  
 9 

 (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 2.5 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 [0], 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 Subsection 2.1 if the registration request is subsequently withdrawn at the request of the Holders of a majority of the Registrable Securities to be registered (in which case all selling Holders shall
bear such expenses pro rata based upon the number of Registrable Securities that were to be included in the withdrawn 

  
 10 

 
registration), unless the Holders of a majority of the Registrable Securities agree to forfeit their right to one registration pursuant to Subsections 2.1(a) or 2.1(b), as the case
may be; provided further that if, at the time of such withdrawal, the Holders shall have learned of a material adverse change in the condition, business, or prospects of the Company from that known to the Holders at the time of their request
and have withdrawn the request with reasonable promptness after learning of such information then the Holders shall not be required to pay any of such expenses and shall not forfeit their right to one registration pursuant to Subsections
2.1(a) or 2.1(b). All Selling Expenses relating to Registrable Securities registered pursuant to this Section 2.6 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 and accountants for each such Holder; any underwriter (as defined in the Securities Act) for each such Holder; and each Person, if any, who
controls such Holder or underwriter within the meaning of the Securities Act or the Exchange Act, against any Damages, and the Company will pay to each such Holder, underwriter, controlling Person, or other aforementioned Person any legal or other
expenses reasonably incurred thereby in connection with investigating or defending any claim or proceeding from which Damages may result, as such expenses are incurred; provided, however, that the indemnity agreement contained in this
Subsection 2.8(a) shall not apply to amounts paid in settlement of any such claim or proceeding if such settlement is effected without the consent of the Company, which consent shall not be unreasonably withheld, nor shall the Company be
liable for any Damages to the extent that they arise out of or are based upon actions or omissions made in reliance upon and in conformity with written information furnished by or on behalf of any such Holder, underwriter, controlling Person, or
other aforementioned Person expressly for use in connection with such registration. 
 (b) To the extent permitted by law, each selling
Holder, severally and not jointly, will indemnify and hold harmless the Company, and each of its directors, each of its officers who has signed the registration statement, each Person (if any), who controls the Company within the meaning of the
Securities Act, legal counsel and accountants for the Company, any underwriter (as defined in the Securities Act), any other Holder selling securities in such registration statement, and any controlling Person of any such underwriter or other
Holder, against any Damages, in each case only to the extent that such Damages arise out of or are based upon actions or omissions made in reliance upon and in conformity with written information furnished by or on behalf of such selling Holder
expressly for use in connection with such registration; and each such selling Holder will pay to the Company and each other aforementioned Person any legal or other expenses reasonably incurred thereby in connection with investigating or defending
any claim or proceeding from which Damages may result, as such expenses are incurred; provided, 

  
 11 

 
however, that the indemnity agreement contained in this Subsection 2.8(b) shall not apply to amounts paid in settlement of any such claim or proceeding if such settlement is
effected without the consent of the Holder, which consent shall not be unreasonably withheld; and provided further that in no event shall the aggregate amounts payable by any Holder by way of indemnity or contribution under Subsections 2.8(b)
and 2.8(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 Subsection 2.8 of notice of the commencement of any action
(including any governmental action) for which a party may be entitled to indemnification hereunder, such indemnified party will, if a claim in respect thereof is to be made against any indemnifying party under this Subsection 2.8, give the
indemnifying party notice of the commencement thereof. The indemnifying party shall have the right to participate in such action and, to the extent the indemnifying party so desires, participate jointly with any other indemnifying party to which
notice has been given, and to assume the defense thereof with counsel mutually satisfactory to the parties; provided, however, that an indemnified party (together with all other indemnified parties that may be 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 Subsection 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 Subsection 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 Subsection 2.8 but it is judicially determined (by the entry of a final judgment or decree by a court of competent jurisdiction and the
expiration of time to appeal or the denial of the last right of appeal) that such indemnification may not be enforced in such case, notwithstanding the fact that this Subsection 2.8 provides for indemnification in such case, or
(ii) contribution under the Securities Act may be required on the part of any party hereto for which indemnification is provided under this Subsection 2.8, then, and in each such case, such parties will contribute to the aggregate
losses, claims, damages, liabilities, or expenses to which they may be subject (after contribution from others) in such proportion as is appropriate to reflect the relative fault of each of the indemnifying party and the indemnified party in
connection with the statements, omissions, or other actions that resulted in such loss, claim, damage, liability, or expense, as well as to reflect any other relevant equitable considerations. The relative fault of the indemnifying party and of the
indemnified party shall be determined by reference to, among other things, whether the untrue or allegedly untrue statement of a material fact, or the omission or alleged omission of a material fact, relates to information supplied by the
indemnifying party or by the indemnified party and the parties’ relative intent, knowledge, access to information, and opportunity to correct or prevent such statement or omission; provided, however, that, in any such case
(x) no Holder will be required to contribute any amount in excess 

  
 12 

 
of the public offering price of all such Registrable Securities offered and sold by such Holder pursuant to such registration statement, and (y) no Person guilty of fraudulent
misrepresentation (within the meaning of Section 11(f) of the Securities Act) will be entitled to contribution from any Person who was not guilty of such fraudulent misrepresentation; and provided further that in no event shall a
Holder’s liability pursuant to this Subsection 2.8(d), when combined with the amounts paid or payable by such Holder pursuant to Subsection 2.8(b), exceed the proceeds from the offering received by such Holder (net of any
Selling Expenses paid by such Holder), except in the case of willful misconduct or fraud by such Holder. 
 (e) Notwithstanding the
foregoing, to the extent that the provisions on indemnification and contribution contained in the underwriting agreement entered into in connection with the underwritten public offering are in conflict with the foregoing provisions, the provisions
in the underwriting agreement shall control. 
 (f) Unless otherwise superseded by an underwriting agreement entered into in connection with
the underwritten public offering, the obligations of the Company and Holders under this Subsection 2.8 shall survive the completion of any offering of Registrable Securities in a registration under this Section 2.8(f), and
otherwise shall survive the termination of this Agreement. 
 2.9 Reports Under Exchange Act. With a view to making
available to the Holders the benefits of SEC Rule 144 and any other rule or regulation of the SEC that may at any time permit a Holder to sell securities of the Company to the public without registration or pursuant to a registration on Form S-3, the Company shall: 
 (a) make and keep available adequate current public information, as those terms
are understood and defined in SEC Rule 144, at all times after the effective date of the registration statement filed by the Company for the IPO; 

(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 ninety (90) days after the effective date of the registration statement filed by the Company for the IPO), the Securities Act, and the Exchange Act (at any time after the Company has become subject to such reporting
requirements), or that it qualifies as a registrant whose securities may be resold pursuant to Form S-3 (at any time after the Company so qualifies); (ii) a copy of the most recent annual or quarterly report
of the Company and such other reports and documents so filed by the Company; and (iii) such other information as may be reasonably requested in availing any Holder of any rule or regulation of the SEC that permits the selling of any such
securities without registration (at any time after the Company has become subject to the reporting requirements under the Exchange Act) or pursuant to Form S-3 (at any time after the Company so qualifies to
use such form). 

  
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 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 Investor Majority, enter into any agreement with any holder or prospective holder of any securities of the Company that would (i) 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; or (ii) allow such holder or prospective holder to initiate a demand for registration of any securities held by such holder or prospective holder; provided that
this limitation shall not apply to any additional Investor who becomes a party to this Agreement in accordance with Subsection 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 one hundred eighty (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 prior to 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 Subsection 2.11 shall apply only to the IPO, shall not apply to distributions to current or former partners,
members or stockholders of a Holder or to the transfer of any shares owned by a Holder in the Company to its Affiliates or any of the Holder’s stockholders, members, partners or other equity holders; provided that the Affiliate, stockholder
member, partner or other equity holder of the Holder agrees to be bound in writing by the restrictions set forth herein, shall not apply to transactions or announcements relating to: (1) securities acquired in the IPO or
(2) securities acquired in open market transactions from and after the IPO, shall not apply to the sale of any shares to an underwriter pursuant to an underwriting agreement, or the transfer of any shares to any trust for the direct or
indirect benefit of the Holder or the immediate family of the Holder, provided that the trustee of the trust agrees to be bound in writing by the restrictions set forth herein, and provided further that any such transfer shall not involve a
disposition for value, and shall be applicable to the Holders only if all officers, directors and stockholders individually and together with their Affiliates owning one percent (1%) or more of the Company’s outstanding Common Stock (after
giving effect to conversion into Common Stock of all outstanding Preferred Stock) are subject to the same restrictions. The underwriters in connection with such registration are intended third party beneficiaries of this Subsection 2.11 and
shall have the right, power and authority to enforce the provisions hereof as though they were a party hereto. Each Holder further agrees to execute such agreements as may be reasonably requested by the underwriters in connection with such
registration that are consistent with this Subsection 2.11 or that are necessary to give further effect thereto. Any discretionary waiver or termination of any or all of such restrictions (including restrictions applicable to directors,
officers and stockholders individually owning more than one percent (1%) of the Company’s outstanding Common Stock (after giving effect to conversion into Common Stock of all outstanding Preferred Stock)) by the Company or the underwriters
shall apply pro rata to all Holders subject to such restrictions, based on the number of shares subject to 

  
 14 

 
such restrictions. In the event that the Company becomes aware that an underwriter has released any director or officer, or any holders of one percent or more of the Company’s outstanding
capital stock from their lock-up agreements pursuant to this Subsection 2.11, the Company shall use its best efforts to cause the underwriters to release the Investors pro rata and the Company shall not
consent to any release that is not pro rata. In the event that any underwriter requests an Investor to sign a lock-up agreement (an “Investor Lock-Up
Agreement”), the Company shall use its best efforts to require all directors, officers and stockholders individually owning one percent (1%) or more of the Company’s outstanding Common Stock (after giving effect to conversion into Common
Stock of all outstanding Preferred Stock) to sign a lock-up agreement with the same terms as the Investor Lock-Up Agreement, and such Investor Lock-Up Agreements shall be applicable to the Holders only if all officers, directors and stockholders individually owning more than one percent (1%) of the Company’s outstanding Common Stock (after giving
effect to conversion into Common Stock of all outstanding Preferred Stock) sign a lock-up agreement with the same terms as the Investor Lock-Up Agreement. The Company
shall notify the Investors if it is aware of any lock-up agreements relating to the Company with more favorable terms than the Investor Lock-Up Agreement. The Company
shall also use its best efforts to cause any future holders of one percent or more of the Company’s outstanding capital stock to agree to a lock-up provision similar to this
Subsection 2.11. 
 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. The Registrable Securities held by Purdue Neuroscience Company shall not be sold, pledged, or otherwise transferred in contravention of that certain License Agreement between the
Company and Purdue Neuroscience Company dated December 31, 2017. 
 (b) Each certificate, instrument, or book entry representing
(i) the Preferred Stock, (ii) the Registrable Securities, and (iii) any other securities issued in respect of the securities referenced in clauses (i) and (ii), upon any stock split, stock dividend,
recapitalization, merger, consolidation, or similar event, shall (unless otherwise permitted by the provisions of Subsection 2.12(c)) be notated with a legend substantially in the following form: 

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

THE SECURITIES REPRESENTED HEREBY MAY BE TRANSFERRED ONLY IN ACCORDANCE WITH THE TERMS OF AN AGREEMENT BETWEEN THE COMPANY AND THE STOCKHOLDER, A COPY OF
WHICH IS ON FILE WITH THE SECRETARY OF THE COMPANY. 

  
 15 

 The Holders consent to the Company making a notation in its records and giving instructions to any transfer
agent of the Restricted Securities in order to implement the restrictions on transfer set forth in this Subsection 2.11. 
 (c) The
holder of such Restricted Securities, by acceptance of ownership thereof, agrees to comply in all respects with the provisions of this Section 2.13(c). Before any proposed sale, pledge, or transfer of any Restricted Securities, unless
there is in effect a registration statement under the Securities Act covering the proposed transaction, the Holder thereof shall give notice to the Company of such Holder’s intention to effect such sale, pledge, or transfer. Each such notice
shall describe the manner and circumstances of the proposed sale, pledge, or transfer in sufficient detail and, if reasonably requested by the Company, shall be accompanied at such Holder’s expense by either (i) a written opinion of
legal counsel who shall, and whose legal opinion shall, be reasonably satisfactory to the Company, addressed to the Company, to the effect that the proposed transaction may be effected without registration under the Securities Act;
(ii) a “no action” letter from the SEC to the effect that the proposed sale, pledge, or transfer of such Restricted Securities without registration will not result in a recommendation by the staff of the SEC that action be
taken with respect thereto; or (iii) any other evidence reasonably satisfactory to counsel to the Company to the effect that the proposed sale, pledge, or transfer of the Restricted Securities may be effected without registration under
the Securities Act, whereupon the Holder of such Restricted Securities shall be entitled to sell, pledge, or transfer such Restricted Securities in accordance with the terms of the notice given by the Holder to the Company. The Company will not
require such a legal opinion or “no action” letter (x) in any transaction in compliance with SEC Rule 144; (y) in any transaction in which such Holder distributes Restricted Securities to an Affiliate of such Holder for no
consideration; or (z) in any internal transaction in which such Holder transfers Restricted Securities to an Affiliate of such Holder that is an entity and that is ultimately controlled by the same parent company as the Holder (or is the
ultimate parent company of the Holder); provided that in the case of clauses (y) and (z), each transferee agrees in writing to be subject to the terms of this Subsection 2.11. Notwithstanding the foregoing, the Company shall be
obligated to reissue promptly unlegended certificates or book entries at the request of any Holder thereof if the Company has completed its IPO and the Holder shall have obtained an opinion of counsel (which counsel may be counsel to the Company) to
the effect that the securities proposed to be disposed of may lawfully be so disposed of without registration, qualification and legend, provided that the second legend listed above shall be removed only at such time as the Holder of such
certificate is no longer subject to any restrictions hereunder. Each certificate, instrument, or book entry representing the Restricted Securities transferred as above provided shall be notated with, except if such transfer is made pursuant to SEC
Rule 144, the appropriate restrictive legend set forth in Subsection 2.12(b), except that such certificate instrument, or book entry shall not be notated with such restrictive legend if, in the opinion of counsel for such Holder and the
Company, such legend is not required in order to establish compliance with any provisions of the Securities Act. 

  
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 2.13 Termination of Registration Rights. The right of any Holder to request
registration or inclusion of Registrable Securities in any registration pursuant to Subsections 2.1 or 2.2 shall terminate upon the earliest to occur of: 

(a) the closing of a Deemed Liquidation Event, as such term is defined in the Company’s Certificate of Incorporation; and 

(b) the fifth anniversary of the IPO. 

3. Information and Observer Rights. 

3.1 Delivery of Financial Statements. The Company shall deliver to each Major Investor, provided that such Major Investor is not
a Competitor: 
 (a) as soon as practicable, but in any event within one hundred and twenty (120) days after the end of each
fiscal year of the Company (i) a balance sheet as of the end of such year, (ii) statements of income and of cash flows for such year and (iii) a statement of stockholders’ equity for as of the end of such
year, all such financial statements audited and certified by independent public accountants of regionally recognized standing selected by the Company; 

(b) as soon as practicable, but in any event within thirty-five (35) days after the end of each of the first three
(3) quarters 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) as soon as practicable, but in any event within thirty-five (35) days after the end of each of the first three
(3) quarters of each fiscal year of the Company, 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; 

(d) as soon as practicable, but in any event thirty (30) days before the end of each fiscal year, a budget and business plan for
the next fiscal year (collectively, the “Budget”), approved by the Board of Directors and prepared on a monthly basis, including balance sheets, income statements, and statements of cash flow for such quarters 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 Subsection 3.1 to provide
information (i) that the Company reasonably determines in good faith to be a trade secret; or (ii) the disclosure of which would adversely affect the attorney-client privilege between the Company and its counsel. 

  
 17 

 If, for any period, the Company has any subsidiary whose accounts are consolidated with those of the
Company, then in respect of such period the financial statements delivered pursuant to the foregoing sections shall be the consolidated and consolidating financial statements of the Company and all such consolidated subsidiaries. 

Notwithstanding anything else in this Subsection 3.1 to the contrary, the Company may cease providing the information set forth in this Subsection
3.1 during the period starting with the date sixty (60) days before the Company’s good-faith estimate of the date of filing of a registration statement if it reasonably concludes it must do so to comply with the SEC rules applicable to
such registration statement and related offering; provided that the Company’s covenants under this Subsection 3.1 shall be reinstated at such time as the Company is no longer actively employing its commercially reasonable efforts
to cause such registration statement to become effective. 
 3.2 Inspection. The Company shall permit each Major Investor
(provided that the Board of Directors has not reasonably determined that such Major Investor is a Competitor), at such Major Investor’s expense, to visit and inspect the Company’s properties; examine its books of account and
records; and discuss the Company’s affairs, finances, and accounts with its officers, during normal business hours of the Company as may be reasonably requested by the Major Investor; provided, however, that the Company shall not
be obligated pursuant to this Subsection 3.2 to provide access to any information that it reasonably and in good faith considers to be a trade secret or confidential information (unless covered by an enforceable
confidentiality agreement, in a form reasonably 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. 
 (a)
As long as Novo Holdings A/S together with its Affiliates own not less than 100,000 shares of Preferred Stock (or an equivalent amount of Common Stock issued upon conversion thereof) (subject to appropriate adjustment for stock splits, stock
dividends, combinations, and other recapitalizations), the Company shall invite a representative of Novo (which representative shall be designated in a written notice to the Company) to attend all meetings of its Board of Directors and its
committees and meetings of the Boards of Directors and committees thereof of its subsidiaries in a nonvoting observer capacity (the “Novo Observer”) and, in this respect, shall give the Novo Observer copies of all notices, minutes,
consents, and other materials that it provides to its directors; provided, however, that the Novo Observer shall agree to hold in confidence and trust; and provided further, that the Company reserves the right to withhold any information and to
exclude the Novo Observer from any meeting or portion thereof if the Board of Directors determines in good faith, upon advice of counsel, that access to such information or attendance at such meeting is reasonably necessary to preserve the
attorney-client privilege between the Company and its counsel or result in disclosure of trade secrets or other highly confidential proprietary technical information. 

(b) As long as Eventide together with its Affiliates own not less than 100,000 shares of Preferred Stock (or an equivalent amount of Common
Stock issued upon conversion thereof) (subject to appropriate adjustment for stock splits, stock dividends, combinations, and other recapitalizations), the Company shall invite a representative of Eventide (which representative shall be designated
in a written notice to the Company) to attend all meetings 

  
 18 

 
of its Board of Directors and its committees and meetings of the Boards of Directors and committees thereof of its subsidiaries in a nonvoting observer capacity (the “Eventide
Observer”) and, in this respect, shall give the Eventide Observer copies of all notices, minutes, consents, and other materials that it provides to its directors; provided, however, that the Eventide Observer shall agree to
hold in confidence and trust; and provided further, that the Company reserves the right to withhold any information and to exclude the Eventide Observer from any meeting or portion thereof if the Board of Directors determines in good faith, upon
advice of counsel, that access to such information or attendance at such meeting is reasonably necessary to preserve the attorney-client privilege between the Company and its counsel or result in disclosure of trade secrets or other highly
confidential proprietary technical information. Eventide may terminate its representative’s status as the Eventide Observer at any time in Eventide’s discretion, including such period of time prior to the consummation of an IPO as Eventide
may determine. 
 (c) As long as Surveyor together with its Affiliates own not less than 100,000 shares of Preferred Stock (or an equivalent
amount of Common Stock issued upon conversion thereof) (subject to appropriate adjustment for stock splits, stock dividends, combinations, and other recapitalizations), the Company shall invite a representative of Surveyor (which representative
shall be designated in a written notice to the Company) to attend all meetings of its Board of Directors and its committees and meetings of the Boards of Directors and committees thereof of its subsidiaries in a nonvoting observer capacity (the
“Surveyor Observer”) and, in this respect, shall give the Surveyor Observer copies of all notices, minutes, consents, and other materials that it provides to its directors; provided, however, that the Surveyor Observer shall agree
to hold in confidence and trust; and provided further, that the Company reserves the right to withhold any information and to exclude the Surveyor Observer from any meeting or portion thereof if the Board of Directors determines in good faith, upon
advice of counsel, that access to such information or attendance at such meeting is reasonably necessary to preserve the attorney-client privilege between the Company and its counsel or result in disclosure of trade secrets or other highly
confidential proprietary technical information. 
 3.4 Termination of Information Rights. The covenants set forth in
Subsection 3.1, Subsection 3.2 and Subsection 3.3 shall terminate and be of no further force or effect (a) immediately before the consummation of the IPO, (b) when the Company first becomes subject
to the periodic reporting requirements of Section 12(g) or 15(d) of the Exchange Act, or (c) upon a Deemed Liquidation Event, as such term is defined in the Company’s Certificate of Incorporation, whichever event occurs first. 

3.5 Confidentiality. Each Investor agrees that such Investor will keep confidential and will not disclose, divulge, or use for any
purpose (other than to monitor and manage its investment in the Company) any confidential information obtained from the Company (including notice of the Company’s intention to file a registration statement), unless such confidential information
(a) is known or becomes known to the public in general (other than as a result of a breach of this Subsection 3.5 by such Investor), (b) is or has been independently developed or conceived by the Investor without use of the
Company’s confidential information, or (c) is or has been made known or disclosed to the Investor by a third party without a breach of any obligation of confidentiality such third party may have to the Company; provided,
however, that an Investor may disclose confidential information (i) to its attorneys, accountants, consultants, and other professionals to the extent necessary to obtain their services in connection with monitoring

  
 19 

 
and managing its investment in the Company; (ii) to any prospective purchaser of any Registrable Securities from such Investor, if such prospective purchaser agrees to be bound by the
provisions of this Subsection 3.5; (iii) to any Affiliate, partner, member, stockholder, or wholly owned subsidiary of such Investor in the ordinary course of business, provided that such Investor informs such Person that such
information is confidential and directs such Person to maintain the confidentiality of such information; (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, provided that, with respect to this clause (v), the Investor promptly notifies the Company of such disclosure and takes reasonable steps to minimize the extent of any such required disclosure. 

3.6 Material Non-Public Information. The Company understands and acknowledges that in the
regular course of Surveyor’s business, Surveyor and its Affiliates will invest in companies that have issued securities that are publicly traded (each, a “Public Company”). Accordingly, the Company covenants and agrees that it
shall not provide any material non-public information about a Public Company to Surveyor or any representative or board observer of Surveyor. In addition, the Company acknowledges and agrees that in no event
shall Surveyor’s confidentiality and non-use obligations hereunder in any manner be deemed or construed as limiting Surveyor or its representatives’ (or any of their respective Affiliates) ability to
trade any security of a Public Company. 
 4. Rights to Future Stock Issuances. 

4.1 Right of First Offer. Subject to the terms and conditions of this Subsection 4.1 and applicable securities
laws, if the Company proposes to offer or sell any New Securities, the Company shall first offer such New Securities to each Investor. An Investor shall be entitled to apportion the right of first offer hereby granted to it in such proportions as it
deems appropriate, among (a) itself and (b) its Affiliates; provided that each such Affiliate (x) is not a Competitor, and (y) agrees to enter into this Agreement and each of the Voting Agreement and Right of First Refusal
and Co-Sale Agreement (each as defined in the Purchase Agreement), as an “Investor” under each such agreement (provided that any Competitor shall not be entitled to any rights as an Investor
under Subsections 3.1, 3.2, 3.3 and 4.1 hereof). 
 (a) The Company shall give notice (the “Offer
Notice”) to each 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 twenty (20) days after the Offer Notice is
given, each 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 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 Investor) bears to the total Common Stock of
the Company then outstanding (assuming full conversion and/or exercise, as 

  
 20 

 
applicable, of all Preferred Stock and other Derivative Securities. At the expiration of such twenty (20) day period, the Company shall promptly notify each Investor that elects to purchase
or acquire all the shares available to it (each, a “Fully Exercising Investor”) of any other Investor’s failure to do likewise. During the ten (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 Investors were entitled to subscribe but that were
not subscribed for by the Investors which is equal to the proportion that the Common Stock issued and held, or issuable (directly or indirectly) upon conversion and/or exercise, as applicable, of Preferred Stock and any other Derivative Securities
then held, by such Fully Exercising Investor bears to the Common Stock issued and held, or issuable (directly or indirectly) upon conversion and/or exercise, as applicable, of the Preferred Stock and any other Derivative Securities then held, by all
Fully Exercising Investors who wish to purchase such unsubscribed shares. The closing of any sale pursuant to this Subsection 4.1(b) shall occur within the later of ninety (90) days of the date that the Offer Notice is given and
the date of initial sale of New Securities pursuant to Subsection 4.1(c). 
 (c) If all New Securities referred to in the Offer
Notice are not elected to be purchased or acquired as provided in Subsection 4.1(b), the Company may, during the ninety (90) day period following the expiration of the periods provided in Subsection 4.1(b), offer and sell
the remaining unsubscribed portion of such New Securities to any Person or Persons at a price not less than, and upon terms no more favorable to the offeree than, those specified in the Offer Notice. If the Company does not enter into an agreement
for the sale of the New Securities within such period, or if such agreement is not consummated within thirty (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 Investors in accordance with this Subsection 4.1. 
 (d) The right of first offer in this
Subsection 4.1 shall not be applicable to (i) Exempted Securities (as defined in the Company’s Certificate of Incorporation); and (ii) shares of Common Stock issued in the IPO. 

4.2 Termination. The covenants set forth in Subsection 4.1 shall terminate and be of no further force or effect
(a) immediately before the consummation of the IPO, or (b) upon a Deemed Liquidation Event, as such term is defined in the Company’s Certificate of Incorporation, whichever event occurs first. 

5. Additional Covenants. 

5.1 Insurance. The Company shall use its commercially reasonable efforts to maintain, from financially sound and reputable insurers,
Directors and Officers liability insurance in an amount not less than $3,000,000 until such time as the Board of Directors determines that such insurance should be discontinued. The policy shall not be cancelable by the Company without prior
approval by the Board of Directors. 

  
 21 

 5.2 Employee Agreements. The Company will cause (a) each person now or hereafter
employed by it or by any subsidiary (or engaged by the Company or any subsidiary as a consultant/independent contractor) with access to confidential information and/or trade secrets to enter into a nondisclosure and proprietary rights assignment
agreement; and (b) each Key Employee to enter into a one (1) year noncompetition and nonsolicitation agreement, substantially in the form approved by the Board of Directors. In addition, the Company shall not amend, modify, terminate,
waive, or otherwise alter, in whole or in part, any of the above-referenced agreements or any restricted stock agreement between the Company and any employee, without the consent of the Board of Directors. 

5.3 Employee Stock. Unless otherwise approved by the Board of Directors, all future employees and consultants of the Company who
purchase, receive options to purchase, or receive awards of shares of the Company’s capital stock after the date hereof shall be required to execute restricted stock or option agreements, as applicable, providing for (a) vesting of shares
over a four (4) year period, with the first twenty-five percent (25%) of such shares vesting following twelve (12) months of continued employment or service, and the remaining shares vesting in equal monthly installments over the following
thirty-six (36) months, and (b) a market stand-off provision substantially similar to that in Subsection 2.11. In addition, unless otherwise approved by
the Board of Directors (including at least three of the Preferred Directors then serving), the Company shall retain a “right of first refusal” on employee transfers until the Company’s IPO and shall have the right to repurchase
unvested shares at cost upon termination of employment of a holder of restricted stock. 
 5.4 Matters Requiring Investor Director
Approval. So long as an aggregate of twenty-five percent (25%) of the Series A Preferred Stock, Series B Preferred Stock, Series B-1 Preferred Stock, Series C Preferred Stock and Series C-1 Preferred Stock originally issued pursuant to each of the Purchase Agreement, that certain Series A Preferred Stock Purchase Agreement between the Company and the other parties thereto dated October 31,
2016, as amended, that certain Series B Preferred Stock Purchase Agreement between the Company and the other parties thereto dated March 13, 2018, as amended, that certain Series B-1 Preferred Stock
Purchase Agreement between the Company and the other parties thereto dated June 18, 2019 and that certain Series C Preferred Stock Purchase Agreement between the Company and the other parties thereto dated November 18, 2019, as amended,
respectively, remain outstanding (subject to appropriate adjustment for stock splits, stock dividends, combinations, and other recapitalizations), the Company hereby covenants and agrees with each of the Investors that it shall not, without approval
of the Board of Directors (including at least three of the Preferred Directors then serving): 
 (a) make, or permit any subsidiary to make,
any loan or advance to, or own any stock or other securities of, any subsidiary or other corporation, partnership, or other entity unless it is wholly owned by the Company; 

(b) make, or permit any subsidiary to make, any loan or advance to any Person, including, without limitation, any employee or director of the
Company or any subsidiary, except advances and similar expenditures in the ordinary course of business or under the terms of an employee stock or option plan approved by the Board of Directors; 

(c) guarantee, directly or indirectly, or permit any subsidiary to guarantee, directly or indirectly, any indebtedness except for trade
accounts of the Company or any subsidiary arising in the ordinary course of business; 

  
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 (d) make any investment other than investments in prime commercial paper, money market
funds, certificates of deposit in any United States bank having a net worth in excess of $100,000,000 or obligations issued or guaranteed by the United States of America, in each case having a maturity not in excess of two years; 

(e) incur any aggregate indebtedness in excess of $100,000 that is not already included in a budget approved by the Board of Directors, other
than trade credit incurred in the ordinary course of business; 
 (f) otherwise enter into or be a party to any transaction with any
director, officer, or employee of the Company or any “associate” (as defined in Rule 12b-2 promulgated under the Exchange Act) of any such Person, including without limitation any “management
bonus” or similar plan providing payments to employees in connection with a Deemed Liquidation Event, as such term is defined in the Company’s Certificate of Incorporation, except for transactions contemplated by this Agreement or the
Purchase Agreement; 
 (g) hire, terminate, or change the compensation of the executive officers, David Goldstein or Stephen Petrou,
including approving any option grants or stock awards to any of them; 
 (h) change the principal business of the Company, enter new lines
of business, or exit the current line of business; 
 (i) sell, assign, license, pledge, or encumber material technology or intellectual
property, other than licenses granted in the ordinary course of business; or 
 (j) make any material investments or acquisitions or enter
into any material joint ventures. 
 5.5 Board Matters. Unless otherwise determined by the vote of a majority of the directors then in
office (including at least three of the Preferred Directors), the Board of Directors shall meet at least quarterly in accordance with an agreed-upon schedule. The Company shall reimburse the nonemployee directors and the Observers 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. Each Preferred
Directors shall be entitled in such person’s discretion to be a member of any committee of the Board of Directors. 
 5.6 Successor
Indemnification. If the Company or any of its successors or assignees consolidates with or merges into any other Person and is not the continuing or surviving corporation or entity of such consolidation or merger, then to the extent necessary,
proper provision shall be made so that the successors and assignees of the Company assume the obligations of the Company with respect to indemnification of members of the Board of Directors as in effect immediately before such transaction, whether
such obligations are contained in the Company’s Bylaws, its Certificate of Incorporation, or elsewhere, as the case may be. 

  
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 5.7 Indemnification Matters. The Company hereby acknowledges that one (1) or
more of the directors nominated to serve on the Board of Directors by the Investors (each a “Fund Director”) may have certain rights to indemnification, advancement of expenses and/or insurance provided by one or more of the
Investors and certain of their affiliates (collectively, the “Fund Indemnitors”). The Company hereby agrees (a) that it is the indemnitor of first resort (i.e., its obligations to any such Fund Director are primary and
any obligation of the Fund Indemnitors to advance expenses or to provide indemnification for the same expenses or liabilities incurred by such Fund Director are secondary), (b) that it shall be required to advance the full amount of expenses
incurred by such Fund Director and shall be liable for the full amount of all expenses, judgments, penalties, fines and amounts paid in settlement by or on behalf of any such Fund Director to the extent legally permitted and as required by the
Company’s Certificate of Incorporation or Bylaws of the Company (or any agreement between the Company and such Fund Director), without regard to any rights such Fund Director may have against the Fund Indemnitors, and, (c) that it
irrevocably waives, relinquishes and releases the Fund Indemnitors from any and all claims against the Fund Indemnitors for contribution, subrogation or any other recovery of any kind in respect thereof. The Company further agrees that no
advancement or payment by the Fund Indemnitors on behalf of any such Fund Director with respect to any claim for which such Fund Director has sought indemnification from the Company shall affect the foregoing and the Fund Indemnitors shall have a
right of contribution and/or be subrogated to the extent of such advancement or payment to all of the rights of recovery of such Fund Director against the Company. 

5.8 Qualified Small Business Stock. The Company shall use commercially reasonable efforts to cause the shares of Preferred Stock, as
well as any shares into which such shares are converted, within the meaning of Section 1202(f) of the Internal Revenue Code (the “Code”), to constitute “qualified small business stock” as defined in
Section 1202(c) of the Code; provided, however, that such requirement shall not be applicable if the Board determines, in its good-faith business judgment, that such qualification is inconsistent with the best interests of the
Company. The Company shall submit to its stockholders (including the Investors) and to the Internal Revenue Service any reports that may be required under Section 1202(d)(1)(C) of the Code and the regulations promulgated thereunder. In
addition, within twenty (20) business days after any Investor’s written request therefor, the Company shall, at its option, either (a) deliver to such Investor a written statement indicating whether (and what portion of) such
Investor’s interest in the Company constitutes “qualified small business stock” as defined in Section 1202(c) of the Code or (b) deliver to such Investor such factual information in the Company’s possession as is
reasonably necessary to enable such Investor to determine whether (and what portion of) such Investor’s interest in the Company constitutes “qualified small business stock” as defined in Section 1202(c) of the Code. 

5.9 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 

  
 24 

 
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. 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. 
 5.10 Publicity. The Company shall not use the
name of Novo, Vida, Eventide, Purdue Neuroscience Company, Point72 Biotech, Harvard Management Private Equity Corporation, Surveyor, Al-Rayyan or OCV or any of their respective Affiliates in any trade publication, marketing materials or otherwise to
the general public or to any other third party, in each case without the prior written consent of Novo, Vida, Eventide, Purdue Neuroscience Company, Point72 Biotech, Harvard Management Private Equity Corporation, Surveyor, Al- Rayyan or OCV, respectively, which consent may be withheld by such party in its sole discretion; provided that (a) the parties anticipate that there will be a mutually-agreed press release announcing the
closing of the transaction contemplated in the Purchase Agreement, which press release shall not include any reference to Al-Rayyan, and (b) following the public announcement contemplated in clause (a), the Company may confirm that Novo, Vida,
Eventide, Purdue Neuroscience Company, Point72 Biotech, Harvard Management Private Equity Corporation, Surveyor, or OCV are investors in the Company (but not the amount or terms thereof) in a form of disclosure that has been previously approved by
Novo, Vida, Eventide, Purdue Neuroscience Company, Point72 Biotech, Harvard Management Private Equity Corporation, Surveyor, or OCV, respectively. Notwithstanding the foregoing, the Company may disclose the terms and/or amount of Novo’s,
Vida’s, Eventide’s, Purdue Neuroscience Company’s, Point72 Biotech’s, Harvard Management Private Equity Corporation’s, Surveyor’s, Al-Rayyan’s or OCV’s investment, without the prior approval of Novo, Vida,
Eventide, Purdue Neuroscience Company, Point72 Biotech, Surveyor, Al-Rayyan or OCV, as applicable, (x) to a bona fide potential investor in or acquirer of the Company in connection with such potential investor’s or acquirer’s due
diligence process or (y) as required by law, rule, regulation or listing standard to do so; in which case the Company (i) shall promptly notify Novo, Vida, Eventide, Purdue Neuroscience Company, Point72 Biotech, Harvard Management Private
Equity Corporation, Surveyor, Al-Rayyan or OCV, as applicable, of such requirement and will cooperate with Novo, Vida, Eventide, Purdue Neuroscience Company, Point72 Biotech, Harvard Management Private Equity Corporation, Surveyor, Al-Rayyan or OCV,
as applicable, to the extent practicable to limit the information disclosed to only such information that the Company, as advised by counsel, is required by law to be disclosed and (ii) will, to the extent practicable and at the request and
expense of Novo, Vida, Eventide, Purdue Neuroscience Company, Point72 Biotech, Harvard Management Private Equity Corporation, Surveyor, Al-Rayyan or OCV, as applicable, seek to obtain a protective order over, or confidential treatment of, such
information. 

  
 25 

 5.11 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 in their capacities as stockholders, shall be borne and paid by the Company. 

5.12 Critical Technology Matters. 

(a) To the extent (i) 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 Defense Production Act of 1950, as amended, including all implementing regulations thereof (the “DPA”), or would reasonably be
considered to constitute the design, fabrication, development, testing, production or manufacture of a critical technology after a recategorization of selected technologies by the U.S. government, or (ii) after execution of the Purchase
Agreement, the Company engages in any activity that could reasonably be considered to constitute the design, fabrication, development, testing, production or manufacture of a critical technology within the meaning of the DPA, the Company shall
promptly notify any non-U.S. Investor of such change in the categorization of its products or services. 

(b) If and only if (i) the Committee on Foreign Investment in the United States (“CFIUS”) requests or requires
that any Investor or the Company file a notice or declaration with CFIUS pursuant to the DPA with respect to the Investor’s investment in the Company (the “Covered Transactions”) or (ii) any Investor or the Company
reasonably determines that a filing with CFIUS with respect to the Covered Transactions is advisable or required by applicable law, then in either case, (i) or (ii): (x) the Company and each Investor shall, and shall cause its affiliates
to, cooperate with the other parties hereto and shall promptly file a CFIUS filing in the requested, required or advisable form in accordance with the DPA; and (y) the Company and each Investor shall, and shall cause its affiliates to,
use reasonable best efforts to obtain, as applicable, the CFIUS Satisfied Condition (as defined in the Purchase Agreement). For the avoidance of doubt, (A) no Investor shall have any obligation to accept or take any action, condition or
restriction with respect to the Covered Transactions in order to achieve the CFIUS Satisfied Condition, and (B) each Investor shall be permitted to withhold, edit, redact and/or otherwise limit disclosure of any information, documents or
materials that it determines, in its sole discretion, are unduly sensitive, related to national security and/or financial or economic sensitivity, unrelated to the Covered Transaction or otherwise unnecessary to achieve the CFIUS Satisfied
Condition. 
 5.13 Munitions. The Company covenants not to control any weapon or explosive device, nuclear or otherwise. 

5.14 Subsidiary Governance. No subsidiary of the Company shall take any action without the approval of the Board to the extent approval
of the Board would be required in the event such action was to be taken by the Company itself, including the requisite groups of directors whose approval would be required in the event such action was to be taken by the Company itself. 

5.15 Harassment Policy. The Company shall, within 60 days following the Closing, adopt and thereafter maintain in effect (i) a Code
of Conduct governing appropriate workplace behavior and (ii) an Anti-Harassment and Discrimination Policy prohibiting discrimination and harassment at the Company. Such policy shall be reviewed and approved by the Board of Directors. 

  
 26 

 5.16 Termination of Covenants. The covenants set forth in this
Section 5, except for Subsections 5.5 and 5.6, shall terminate and be of no further force or effect (a) immediately before the consummation of the IPO, or (b) upon a Deemed Liquidation Event, as such
term is defined in the Company’s 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 (a) is an Affiliate, partner or stockholder of a Holder; (b) is a Holder’s Immediate Family Member or trust for the benefit of an individual Holder or one or more of such Holder’s
Immediate Family Members; or (c) after such transfer, holds at least One Hundred Thousand (100,000) 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
Subsection 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, partner 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 have a single attorney-in-fact for the purpose of
exercising any rights, receiving notices, or taking any action under this Agreement. The terms and conditions of this Agreement inure to the benefit of and are binding upon the respective successors and permitted assignees of the parties. Nothing in
this Agreement, express or implied, is intended to confer upon any party other than the parties hereto or their respective successors and permitted assignees any rights, remedies, obligations or liabilities under or by reason of this Agreement,
except as expressly provided herein. 
 6.2 Governing Law. This Agreement shall be governed by the internal law of the State of
Delaware. 
 6.3 Counterparts. This Agreement may be executed in two (2) or more counterparts, each of which shall be deemed an
original, but all of which together shall constitute one and the same instrument. Counterparts may be delivered via facsimile, electronic mail (including pdf or any electronic signature complying with the U.S. federal ESIGN Act of 2000, e.g.,
www.docusign.com) or other transmission method and any counterpart so delivered shall be deemed to have been duly and validly delivered and be valid and effective for all purposes. 

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. 

  
 27 

 6.5 Notices. All notices and other communications given or made pursuant to this
Agreement shall be in writing and shall be deemed effectively given upon the earlier of actual receipt or (a) personal delivery to the party to be notified; (b) when sent, if sent by electronic mail or facsimile during the recipient’s
normal business hours, and if not sent during normal business hours, then on the recipient’s next business day; (c) five (5) days after having been sent by registered or certified mail, return receipt requested, postage prepaid; or
(d) one (1) 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 Subsection 6.5. If notice is given to the Company, a copy (which shall not constitute notice) shall also
be sent to Goodwin Procter LLP, 100 Northern Avenue, Boston, MA 02210, Attention: Richard A. Hoffman and William D. Collins. 
 6.6
Amendments and Waivers. Any term of this Agreement may be amended and the observance of any term of this Agreement may be waived (either generally or in a particular instance, and either retroactively or prospectively) only with the written
consent of the Company and the Investor Majority; provided that: 
 (a) the Company may in its sole discretion waive compliance with
Subsection (c) (and the Company’s failure to object promptly in writing after notification of a proposed assignment allegedly in violation of Subsection (c) shall be deemed to be a waiver); 

(b) any provision hereof may be waived by any waiving party on such party’s own behalf, without the consent of any other party; 

(c) Subsections 5.6 and 5.7 and this clause of Section 6.6 shall not be amended or waived without the consent of
Clarus, Novo and Vida; 
 (d) Subsections 6.13 and 6.14 and this clause of Section 6.6 shall not be amended or
waived without the consent of Clarus, Novo, Vida and Eventide; 
 (e) the definitions of “Affiliate” as it pertains to Novo
Holdings A/S, and “Novo”, Section 3.3(a), Section 5.10, and Subsection 5.12(b) as they pertain to Novo, and this clause of Section 6.6 shall not be amended or waived without the consent of Novo
Holdings A/S; 
 (f) Section 5.10 and this clause of Section 6.6 as they pertain to Vida shall not be amended or
waived without the consent of Vida Ventures, LLC; 
 (g) Subsection 3.3(b) and this clause of Section 6.6 shall not be
amended or waived without the consent of Eventide; 
 (h) Section 3.3(c), Section 3.6, Section 5.10 and
Section 6.13 as they pertain to Surveyor, and this clause of Section 6.6 shall not be amended or waived without the consent of Surveyor; 

(i) Subsection 5.10 and this clause of Section 6.6 shall not be amended or waived without the consent of Harvard Management
Private Equity Corporation; 

  
 28 

 (j) Subsection 5.10 and this clause of Section 6.6 shall not be amended
or waived without the consent of Al-Rayyan; 
 (k) Subsections 5.10, 6.13 and 6.14, and this clause of
Section 6.6 shall not be amended or waived without the consent of OCV; and 
 (l) the definitions of “Affiliate” as it
pertains to a specific Holder shall not be amended or waived without the consent of such Holder. 
 (m) Notwithstanding the foregoing, this
Agreement may not be amended or terminated and the observance of any term hereof may not be waived with respect to any Investor without the written consent of such Investor, unless such amendment, termination, or waiver applies to all Investors in
the same fashion. The Company and the Investors agree 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; provided, however, that in the event that any Investor or its Affiliate nonetheless purchases New
Securities being issued in such financing transaction after such waiver has been obtained (any such Investor and its Affiliates, collectively, a “Participating Investor”), then each other Investor shall be permitted to purchase up
to the same percentage (not to exceed 100%) of its pro rata share of New Securities issued in such financing transaction as the percentage of the pro rata share of the New Securities so purchased by the Participating Investor purchasing the largest
portion of such Participating Investor’s pro rata share in such financing transaction. The Company shall give prompt notice of any amendment or termination hereof or waiver hereunder to any party hereto that did not consent in writing to such
amendment, termination, or waiver. Any amendment, termination, or waiver effected in accordance with this Subsection 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. 

(n) Subsection 6.6(m) and this clause of Section 6.6 shall not be amended or waived without the consent of each of the
Investors. 
 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 Affiliated persons may apportion such rights as among themselves in any
manner they deem appropriate. 

  
 29 

 6.9 Additional Investors. Notwithstanding anything to the contrary contained herein,
if the Company issues additional shares of the Company’s Preferred Stock after the date hereof, whether pursuant to the Purchase Agreement or otherwise, any purchaser of such shares of 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, except, with respect to any Investor, as modified by any side letter agreement between such Investor and the Company, and any other written or oral agreement relating to the
subject matter hereof existing between the parties is expressly canceled. Upon the effectiveness of this Agreement, the Prior Agreement shall be deemed amended and restated and superseded and replaced in its entirety by this Agreement, and shall be
of no further force or effect. 
 6.11 Dispute Resolution. The parties (a) hereby irrevocably and unconditionally submit to the
jurisdiction of the state courts of the state of Delaware and to the jurisdiction of the United States District Court for the District of Delaware for the purpose of any suit, action or other proceeding arising out of or based upon this Agreement,
(b) agree not to commence any suit, action or other proceeding arising out of or based upon this Agreement except in the state courts of the state of Delaware or the United States District Court for the District of Delaware, and (c) hereby
waive, and agree not to assert, by way of motion, as a defense, or otherwise, in any such suit, action or proceeding, any claim that it is not subject personally to the jurisdiction of the above-named courts, that its property is exempt or immune
from attachment or execution, that the suit, action or proceeding is brought in an inconvenient forum, that the venue of the suit, action or proceeding is improper or that this Agreement or the subject matter hereof may not be enforced in or by such
court. 
 WAIVER OF JURY TRIAL: EACH PARTY HEREBY WAIVES ITS RIGHTS TO A JURY TRIAL OF ANY CLAIM OR CAUSE OF ACTION BASED UPON OR ARISING OUT OF THIS
AGREEMENT, THE OTHER TRANSACTION DOCUMENTS, THE SECURITIES OR THE SUBJECT MATTER HEREOF OR THEREOF. THE SCOPE OF THIS WAIVER IS INTENDED TO BE ALL-ENCOMPASSING OF ANY AND ALL DISPUTES THAT MAY BE FILED IN ANY
COURT AND THAT RELATE TO THE SUBJECT MATTER OF THIS TRANSACTION, INCLUDING, WITHOUT LIMITATION, CONTRACT CLAIMS, TORT CLAIMS (INCLUDING NEGLIGENCE), BREACH OF DUTY CLAIMS, AND ALL OTHER COMMON LAW AND STATUTORY CLAIMS. THIS SECTION HAS BEEN FULLY
DISCUSSED BY EACH OF THE PARTIES HERETO AND THESE PROVISIONS WILL NOT BE SUBJECT TO ANY EXCEPTIONS. EACH PARTY HERETO HEREBY FURTHER WARRANTS AND REPRESENTS THAT SUCH PARTY HAS REVIEWED THIS WAIVER WITH ITS LEGAL COUNSEL, AND THAT SUCH PARTY
KNOWINGLY AND VOLUNTARILY WAIVES ITS JURY TRIAL RIGHTS FOLLOWING CONSULTATION WITH LEGAL COUNSEL. 

  
 30 

 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. 

6.13 Right to Conduct Activities. The Company hereby agrees and acknowledges that certain of the Investors and their Affiliates
and representatives are investment funds or other institutional 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 such Investor may 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 such Investor
shall not be liable to the Company for any claim arising out of, or based upon, (i) the investment by such Investor in any entity competitive with the Company, (ii) actions taken by any partner, officer or other representative of such
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 Investor; provided, however, that the foregoing shall not relieve (x) such Investor 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. 

6.14 Limitation of Liability. The total liability, in the aggregate, of an Investor for any and all claims, losses, costs or
damages, including attorneys’ and accountants’ fees and expenses and costs of any nature whatsoever or claims or expenses resulting from or in any way related to this Agreement from any cause or causes (collectively,
“Claims”) shall be several and not joint with the other Investors and shall not exceed the total consideration paid to the Company by such Investor for the Shares (as defined in the Purchase Agreement) under the Purchase Agreement.
No Affiliate, officer, director, employee or agent of any Purchaser (and that is itself not also a Purchaser) shall have any liability for any Claim whatsoever. It is intended that this limitation apply to any and all liability or cause of action
however alleged or arising, unless otherwise prohibited by law. 
 [Remainder of Page Intentionally Left Blank] 

  
 31 

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

			
	COMPANY:
	
	PRAXIS PRECISION MEDICINES, INC.
		
	By: 	 	 /s/Marcio Souza

	Name:	 	Marcio Souza
	Title: 	 	President and Chief Executive Officer

 
			
		
	Address:	 	One Broadway, 16th Floor
		 	Cambridge, MA 02142

 [Signature Page to Fourth Amended and Restated Investors’ Rights Agreement] 

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

			
	INVESTOR:
	
	NOVO HOLDINGS A/S
		
	By:	 	 /s/ Thomas Dyrberg

	Name: 	 	Thomas Dyrberg, under specific power of attorney
	Title: 	 	Managing Partner

 
			
		
	Address:	 	
	Novo Holdings A/S
	Tuborg Havnevej 19
	DK-2900 Hellerup
	Denmark
	Attn: Thomas Dyrberg and Heather Ludvigsen
	Email: TDY@novo.dk; hlud@novo.dk with a copy (which shall not constitute notice) to:
	Novo Ventures (US), Inc. 501 2nd Street, Suite 300
	San Francisco, CA 94107
	Attention: Junie Lim
	Email: jeql@novo.dk

 [Signature Page to Fourth Amended and Restated Investors’ Rights Agreement] 

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

			
	INVESTOR:
	
	VIDA VENTURES, LLC
		
	By:	 	 /s/ Stefan Vitorovic

	Name: 	 	Stefan Vitorovic
	Title: 	 	Managing Director

 
			
		
	Address:	 	
	40 Broad Street, Suite 201
	Boston, MA 02109

 [Signature Page to Fourth Amended and Restated Investors’ Rights Agreement] 

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

			
	INVESTOR:
	
	MUTUAL FUND SERIES TRUST, ON BEHALF OF EVENTIDE HEALTHCARE & LIFE SCIENCES FUND
		
	By:	 	 /s/ Erik Naviloff

	Name:	 	Erik Naviloff
	Title:	 	Treasurer
	
	Custodian Address:
		
		 	U.S. Bank Trust Services
		 	Trust Services
		 	Attn: Physical Processing, MK-WI-S302 1555 N RiverCenter Drive, Suite 302
		 	Milwaukee, WI 53212
	
	MUTUAL FUND SERIES TRUST, ON BEHALF OF EVENTIDE GILEAD FUND
		
	By:	 	 /s/ Erik Naviloff

	Name:	 	Erik Naviloff
	Title:	 	Treasurer
	
	Custodian Address:
		
		 	U.S. Bank Trust Services
		 	Trust Services
		 	Attn: Physical Processing, MK-WI-S302 1555 N RiverCenter Drive, Suite 302
		 	Milwaukee, WI 53212

 [Signature Page to Fourth Amended and Restated Investors’ Rights Agreement] 

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

			
	INVESTOR:
	
	CLARUS LIFESCIENCES III, L.P.
		
	By:	 	Clarus Ventures III GP, L.P., its general partner
		
	By:	 	Blackstone Clarus III L.L.C., its general partner
		
	By:	 	Blackstone Holdings II L.P., its managing member
		
	By:	 	Blackstone Holdings I/II GP L.L.C., its general partner
		
	By:	 	Blackstone Group Inc., its managing member
		
	By:	 	 /s/ Nicholas G. Galakatos

	Name:	 	Nicholas G. Galakatos
	Title:	 	Senior Managing Director

 
			
		
	Address:	 	101 Main Street, Suite 1210
		 	Cambridge, MA 02142

 [Signature Page to Fourth Amended and Restated Investors’ Rights Agreement] 

 IN WITNESS WHEREOF, the parties have executed this Fourth 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: 	 	CFO & CCO
		
	Address:	 	110 Greene Street, Suite 800
		 	New York, New York 10012

 [Signature Page to Fourth Amended and Restated Investors’ Rights Agreement] 

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

			
	INVESTOR:
	
	POINT72 BIOTECH PRIVATE INVESTMENTS, LLC
		
	By:	 	 /s/ Vincent Tortorella

	Name: 	 	Vincent Tortorella
	Title: 	 	Authorized Signatory

 
			
		
	Address:	 	c/o Point72, L.P.
		 	72 Cummings Point Road
		 	Stamford, CT 06902

 [Signature Page to Fourth Amended and Restated Investors’ Rights Agreement] 

 IN WITNESS WHEREOF, the parties have executed this Fourth 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/ Christopher L. Ramsay

	Name: 	 	Christopher L. Ramsay
	Title: 	 	Authorized Signatory
	Address:	 	601 Lexington Avenue,
		 	New York, NY 10022

 [Signature Page to Fourth Amended and Restated Investors’ Rights Agreement] 

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

			
	INVESTOR:
	
	AMPLE PLUS FUND LIMITED PARTNERSHIP
		
	By:	 	 /s/ Luke Li

	Name: 	 	Luke Li
	Title: 	 	General Managing Partner
		
	Address:	 	One Broadway, 9th Floor
		 	Cambridge, MA 02142

 [Signature Page to Fourth Amended and Restated Investors’ Rights Agreement] 

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

			
	INVESTOR:
	
	IRVING INVESTORS PRIVATES HPC XVII, LLC
		
	By:	 	 /s/ Jeremy Abelson

	Name: Jeremy Abelson
	Title: Manager

 [Signature Page to Fourth Amended and Restated Investors’ Rights Agreement] 

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

			
	INVESTOR:
	
	IRVING INVESTORS KCM, LLC
		
	By:	 	Kingdon Capital Management, LLC,
		 	as investment manager
		
	By:	 	 /s/ William Walsh

	Name:	 	William Walsh
	Title:	 	Chief Financial Officer
		
	Address:	 	c/o Kingdon Capital Management, LLC 152 W. 57th Street, 50th Floor New York, NY 10019

 [Signature Page to Fourth Amended and Restated Investors’ Rights Agreement] 

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

			
	INVESTOR:
	
	VERITION MULTI-STRATEGY MASTER FUND LTD
		
	By:	 	 /s/ William Anderson

	Name: William Anderson
	Title: Authorized Signatory
	
	Address:

 [Signature Page to Fourth Amended and Restated Investors’ Rights Agreement] 

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

			
	INVESTOR:
	
	CORMORANT PRIVATE HEALTHCARE FUND II, LP
		
	By:	 	Cormorant Private Healthcare GP II, LLC
		
	By:	 	 /s/ Bihua Chen

	Name: Bihua Chen
	Title: Managing Member of the GP
	
	Address:
	200 Clarendon Street, 52nd Floor
	Boston, MA 02116
	
	INVESTOR:
	
	CORMORANT GLOBAL HEALTHCARE MASTER FUND, LP
		
	By:	 	Cormorant Global Healthcare GP, LLC
		
	By:	 	 /s/ Bihua Chen

	Name: Bihua Chen
	Title: Managing Member of the GP
	
	Address:
	200 Clarendon Street, 52nd Floor
	Boston, MA 02116

 [Signature Page to Fourth Amended and Restated Investors’ Rights Agreement] 

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

			
	INVESTOR:
	
	ADAGE CAPITAL PARTNERS, LP
		
	By:	 	 /s/ Dan Lehan

	Name: Dan Lehan
	Title: COO
	
	Address:

 [Signature Page to Fourth Amended and Restated Investors’ Rights Agreement] 

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

			
	INVESTOR:
	
	HARVARD MANAGEMENT PRIVATE EQUITY CORPORATION
		
	By:	 	 /s/ Richard Slocum

	Name: Richard Slocum
	Title: Authorized Signatory
		
	By:	 	 /s/ Kathryn Murtagh

	Name: Kathryn Murtagh
	Title: Authorized Signatory
	
	Address:
	600 Atlantic Ave
	Boston, MA 02210

 [Signature Page to Fourth Amended and Restated Investors’ Rights Agreement] 

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

			
	INVESTOR:
	
	OCV FUND I L.P.
		
	By:	 	 /s/ Zohar Loshitzer

	Name: Zohar Loshitzer
	Title: Principal

 
			
		
	Address:	 	4700 Wilshire Blvd.
		 	Los Angeles, CA 90010

 [Signature Page to Fourth Amended and Restated Investors’ Rights Agreement] 

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

			
	INVESTOR:
	
	AL-RAYYAN HOLDING LLC
		
	By:	 	 /s/ Ahmad Al-Khanji

	Name: Ahmad Al-Khanji
	Title: Director
	
	Address:
	
	Al-Rayyan Holding LLC c/o Qatar Investment Authority
	Ooredoo Tower (Building 14)
	Al Dafna Street (Street 801)
	Al Dafna (Zone 61)
	Doha, Qatar
	Attention: Mohamed Adel Ghanem, MD, Executive Director, Healthcare, and Kenneth McLaren, Chief, Investment Execution
	Email: notices.m&a@qia.qa and Notices_Health_Care@qia.qa
	
	With copies (which shall not constitute notice) to: General Counsel
	Qatar Investment Authority
	Ooredoo Tower (Building 14)
	Al Dafna Street (Street 801)
	Al Dafna (Zone 61)
	Doha, Qatar
	Email: notices.legal@qia.qa
	
	A copy (which shall not constitute notice) shall also be sent to:
	Shearman & Sterling LLP 535 Mission Street, 25th Floor
	San Francisco, CA 94105
	Attn: Michael S. Dorf (mdorf@shearman.com)

 [Signature Page to Fourth Amended and Restated Investors’ Rights Agreement] 

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

			
	INVESTOR:
		
	By:	 	 /s/ Marcio Souza

	Name: Marcio Souza
	
	Address:

 [Signature Page to Fourth Amended and Restated Investors’ Rights Agreement] 

 SCHEDULE A 

INVESTORS 
 Name and Address

 Clarus Lifesciences III, L.P. 
 101 Main
Street, Suite 1210 
 Cambridge, MA 02142 
 Edward Scolnick

 1201 Magnolia Drive 
 Wayland, MA 01778 

Gilead Sciences, Inc. 
 333 Lakeside Drive 

Foster City, CA 9440 
 Novo Holdings A/S 

Tuborg Havnevej 19 

DK-2900 Hellerup 
 Denmark

 Attn: Thomas Dyrberg and Heather Ludvigsen 
 Email:
TDY@novo.dk; hlud@novo.dk 
 with a copy (which shall not constitute notice) to: 

Novo Ventures (US), Inc. 
 501 2nd Street, Suite 300 

San Francisco, CA 94107 
 Attention: Junie Lim 

Email: jeql@novo.dk 
 Vida Ventures, LLC 

c/o VV Manager LLC 
 40 Broad Street, Suite 201 

Boston, MA 02109 
 Attn: Stefan Vitorovic 

Purdue Neuroscience Company 
 One Stamford Forum 

201 Tresser Boulevard 
 Stamford, Connecticut 06901-3431 

With copies to: 
 Purdue Pharma L.P. 

One Stamford Forum 201 
 Tresser Boulevard

 
Stamford, Connecticut 06901-3431 
 Attention: General Counsel 

Norton Rose Fulbright US LLP 
 1301 Avenue of the Americas 

New York, New York 10019-6022 
 Attention: Stuart D. Baker 

Robert DeBenedetto 
 3618 Pontina Court 

Pleasanton, CA 94566 
 Mutual Fund Series Trust, On Behalf Of

 Eventide Healthcare & Life Sciences Fund 

Custodian Address: 
 U.S. Bank Trust Services 

Trust Services 
 Attn: Physical Processing, MK-WI-S302 
 1555 N RiverCenter Drive, Suite 302 

Milwaukee, WI 53212 
 Mutual Fund Series Trust, On Behalf Of

 Eventide Gilead Fund 
 Custodian Address: 

U.S. Bank Trust Services 
 Trust Services 

Attn: Physical Processing, MK-WI-S302 

1555 N RiverCenter Drive, Suite 302 
 Milwaukee, WI 53212 

Avoro Life Sciences Fund LLC 
 110 Greene Street, Suite
800 
 New York, New York 10012 
 Al-Rayyan Holding LLC

 c/o Qatar Holding LLC 
 Ooredoo Tower (Building 14) 

Al Dafna Street (Street 801) 
 Al Dafna (Zone 61) 

Doha, Qatar 
 Attention: Mohamed Adel Ghanem, MD, 

Executive Director, Healthcare, and 
 Kenneth McLaren, Chief,
Investment Execution 
 Email: notices.m&a@qia.qa and Notices_Health_Care@qia.qa 

 With copies (which shall not constitute notice) to: 

General Counsel 
 Qatar Investment Authority 

Ooredoo Tower (Building 14) 
 Al Dafna Street (Street 801) 

Al Dafna (Zone 61) 
 Doha, Qatar 

Email: notices.legal@qia.qa 
 and 

Shearman & Sterling LLP 
 535 Mission Street, 25th Floor

 San Francisco, CA 94105 
 Attn: Michael S. Dorf
(mdorf@shearman.com) 
 Point72 Biotech Private Investments, LLC 

c/o Point72, L.P. 
 72 Cummings Point Road 

Stamford, CT 06902 
 Attn: Legal 

Citadel Multi-Strategy Equities Master Fund Ltd. 
 c/o
Citadel Advisors LLC 
 601 Lexington Avenue 
 New York, New
York 10022 
 Attention: Noah Goldberg and Harry Greenbaum 

CitadelAgreementNotice@citadel.com; 
 noah.goldberg@citadel.com;

 Harry.Greenbaum@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 

Ample Plus Fund Limited Partnership 
 One Broadway, 9th
Floor, 
 Cambridge, MA 02142 
 With copies sent by email to
both 
 luke@ampleplus.fund and andrew.aherrera@ampleplus.fund 

 Irving Investors Privates HPC XVII, LLC 

205 Detroit St (4th Floor) 
 Denver, CO 80206 

Attention: Jeremy Ableson 
 Email: jableson@irvinginvestors.com

 Irving Investors KCM, LLC 
 c/o Kingdon Capital
Management, LLC 
 152 W. 57th Street, 50th Floor 
 New York, NY
10019 
 Attention: Richard Weinstein 
 Email: legal@kingdon.com

 Verition Multi-Strategy Master Fund LTD 
 c/o
Verition Fund Management LLC 
 1 American Lane 
 Greenwich CT
06831 
 Cormorant Private Healthcare Fund II, LP 
 200
Clarendon Street, 52nd Floor 
 Boston, MA 02116 
 Cormorant
Global Healthcare Master Fund, LP 
 200 Clarendon Street, 52nd Floor 

Boston, MA 02116 
 Adage Capital Partners, LP 

200 Clarendon St, 52nd Floor 
 Boston, MA 02116 

Attn: Dan Lehan 
 Harvard Management Private Equity
Corporation 
 600 Atlantic Avenue 
 Boston, MA 02210 

Attn: Marcus Loveland / Emily Holden 
 Tel: 617-720-6594 / 617-720-6526 

OCV Fund I L.P. 
 4700 Wilshire Blvd 

Los Angeles, CA 90010 
 Attn: Chris Bostick / Zohar Loshitzer 

Tel: 323-860-7444 / 323-860-9505 
 Marcio Souza 

7 Lenore Rd, 
 Tewksbury Twp, NJ 07830 

 SCHEDULE B 

AFFILIATES 
 Clarus Lifesciences I, L.P.

 Clarus Lifesciences II, L.P. 
 Clarus Lifesciences IV, L.P.

 Clarus Ventures III GP, L.P. 
 Clarus Ventures LLC 

Blackstone Clarus III LLC 
 Blackstone Holdings II, LP. 

Clarus Defined Exit I, LP 
 Clarus DE II, LPEX-10.15

 Exhibit 10.15 

CERTAIN CONFIDENTIAL PORTIONS OF THIS EXHIBIT HAVE BEEN OMITTED AND REPLACED WITH “[***]”. SUCH IDENTIFIED INFORMATION HAS BEEN
EXCLUDED FROM THIS EXHIBIT BECAUSE IT IS (I) NOT MATERIAL AND (II) WOULD LIKELY CAUSE COMPETITIVE HARM TO THE COMPANY IF DISCLOSED. 

LICENSE AGREEMENT 
 This
License Agreement (“Agreement”) is made effective as of December 31, 2017 (the “Effective Date”) by and between PRAXIS PRECISION MEDICINES,
INC., a Delaware corporation having a place of business at 101 Main Street, Cambridge, MA 02142 (“Licensee”), and PURDUE NEUROSCIENCE COMPANY, a
Delaware general partnership having a place of business at One Stamford Forum, 201 Tresser Boulevard, Stamford, Connecticut 06901-3431 (“Licensor”). 

RECITALS 
 WHEREAS,
Licensor is the owner of and has rights to Know-How concerning a GABA-A Positive Allosteric Modulator designated as V134444; 

WHEREAS, Licensee is a biopharmaceutical company engaged, among other things, in the research and development of pharmaceutical
products; 
 WHEREAS, Licensee desires to obtain certain rights to research, develop and commercialize pharmaceutical products
through the use of Licensor’s Know-How, and Licensor desires to grant Licensee such rights, all as set forth below; and 

NOW THEREFORE, based on the foregoing premises and the mutual covenants and obligations set forth below, the Parties agree as follows:

 ARTICLE 1 

DEFINITIONS 
 Unless this
Agreement expressly provides to the contrary, the following terms, whether used in the singular or plural, have the respective meanings set forth below. The words “include,” “includes” and “including” when used in this
Agreement are deemed to be followed by the phrase “but not limited to”. 
 1.1 “Additional Agreements” has
the meaning set forth in 6.2(c). 
 1.2 “Additional Securities” means shares of capital stock, convertible securities
or warrants, options, or other rights to subscribe for, purchase or acquire from Licensee any capital stock of Licensee; provided that, “other rights to subscribe for, purchase or acquire” shall not include (i) preemptive or other
rights to participate in new offerings of securities by Licensee after the Effective Date, (ii) obligations under a purchase agreement for preferred stock of Licensee to acquire additional shares of such preferred stock on the same terms as
those purchased at an initial closing upon the passage of time or meeting (or waiver) of specified Licensee performance conditions, provided that, for clarity, upon purchase or acquisition all such shares of preferred stock shall be “Additional
Securities” for purposes of the Agreement, or (iii) anti-dilution provisions that have not been triggered and (iv) anti-dilution provisions that would not be triggered by the issuance of equity securities to Licensor pursuant to or in
connection with the provisions of this Agreement. 
 1.3 “Affiliate” means with respect to a Party, any person, firm,
trust, partnership, corporation, company or other entity or combination thereof that, directly or indirectly through one (1) or more intermediaries, controls, is controlled by, or is under common control with such Party. In this definition,
“control” and “controlled” means ownership of fifty percent (50%) or more, including ownership by one or more trusts with substantially the same beneficial interests, of the voting and equity rights of such person,

 
firm, trust, partnership, corporation, company or other entity or combination thereof or the power to direct the management of such person, firm, trust, partnership, corporation, company or other
entity or combination thereof. Notwithstanding the foregoing, for purposes of Sections 1.60, 1.77, 3.2(a), 3.2(b), 8.1, 9.4(b), 9.5(c) and 11.8, Affiliates of Licensee shall exclude any person, firm, trust, partnership, corporation, company or other
entity or combination thereof controlled by Clarus Lifesciences III, L.P. or other fund under common control with Clarus Lifesciences III, L.P. (collectively, “Clarus Affiliate Persons”) other than Licensee and its subsidiaries and
Clarus Affiliate Persons that have been granted rights by Licensee or its Affiliates with respect to Licensed Products. 
 1.4
“Agreement” has the meaning set forth in the preamble. 
 1.5 “Anti-Dilution Shares” has the
meaning set forth in Section 3.3(b). 
 1.6 “Bankruptcy Code” has the meaning set forth in Section 9.4(b).

 1.7 “Board” means the Board of Directors of Licensee. 

1.8 “Business Day” means any day other than a day on which the commercial banks in New York City are authorized or
required to be closed. 
 1.9 “Calendar Quarter” means the respective periods of three (3) consecutive calendar
months ending on March 31, June 30, September 30 and December 31; provided, however, that (a) the first Calendar Quarter of the Term shall extend from the commencement of such period to the end of the first complete Calendar
Quarter thereafter; and (b) the last Calendar Quarter of the Term shall end upon the expiration or termination of this Agreement. 

1.10 “Calendar Year” means (a) for the first year of the Term, the period beginning on the Effective Date and
ending on December 31, 2017, (b) for each year of the Term thereafter, each successive period beginning on January 1 and ending twelve (12) consecutive calendar months later on December 31, and (c) for the last year of the
Term, the period beginning on January 1 of the year in which the Agreement expires or terminates and ending on the effective date of expiration or termination of this Agreement. 

1.11 “Change of Control” means, with respect to a Party, any of the following events: (a) any Third Party (or
group of Third Parties acting in concert) acquires, directly or indirectly, shares of such Party representing at least a majority of the voting power (where voting refers to being entitled to vote for the election of directors) then outstanding of
such Party; (b) such Party consolidates with or merges into another corporation or entity which is a Third Party, or any corporation or entity which is a Third Party consolidates with or merges into such Party, in either event pursuant to a
transaction in which at least a majority of the voting power of the acquiring or resulting entity outstanding immediately after such consolidation or merger is not held by the holders of the outstanding voting power of such Party immediately
preceding such consolidation or merger; or (c) such Party conveys, transfers, licenses and/or leases all or substantially all of its assets to a Third Party. Notwithstanding anything to the contrary in this paragraph, a Change of Control shall
not include any transaction or series of transactions: (i) involving solely a Party and its Affiliates, (ii) in which the stockholders of a Party immediately prior to such transaction hold at least fifty (50%) of the voting power of the
surviving company or ultimate parent company of the surviving company, (iii) in which voting securities of a Party are acquired by any employee benefit plan (or related trust) sponsored or maintained by such Party or its Affiliates; or
(iv) for bona fide capital raising purposes (including a public offering) or tax purposes (including the change of place of incorporation or domicile of a Party). 

  
 2 

 1.12 “Combination Product” means any single product in finished form
containing both a Licensed Product and one or more other active ingredients or functional devices. 
 1.13 “Commercially
Reasonable Efforts” means using such effort and employing such resources that are substantially similar to the effort and resources that a biopharmaceutical company similarly situated to Licensee would devote to a product of similar market
potential, profit potential and strategic value at a similar stage of its product life, taking into consideration all relevant factors, including the nature of the product, the clinical setting in which it is expected to be used, stage of
development, mechanism of action, efficacy and safety relative to competitive products in or expected to be introduced into the marketplace, difficulties associated with technology transfer, process development,
scale-up or manufacturing, safety issues, legal difficulties and intellectual property ownership, actual or anticipated regulatory authority approved labeling, the nature and extent of market exclusivity
(including patent coverage and Regulatory Exclusivity), cost and likelihood of obtaining regulatory approval, but excluding from such consideration all payments due to Purdue under this Agreement. Commercially Reasonable Efforts will be determined
on a market-by-market and indication-by-indication basis for a particular product, and it
is anticipated that the level of effort will be different for different markets, and will change over time, reflecting changes in the status of the product and the market(s) involved. 

1.14 “Common Stock” means shares of the Licensee’s common stock, par value $0.001 per share. 

1.15 “Compounds” means V134444 and any metabolites, salts, esters, hydrates, solvates, isomers, enantiomers,
crystalline forms, co-crystalline forms, amorphous forms, free acid forms, free base forms, pro-drug (including any ester
pro-drug) forms, racemates, polymorphs, chelates, stereoisomers, or tautomers of V134444, and all optically active forms thereof, provided however that all of the foregoing excludes ganaxolone and any salts,
hydrates, solvates, isomers, enantiomers, crystalline forms, co-crystalline forms, amorphous forms, free acid forms, free base forms, racemates, polymorphs, chelates, stereoisomers, and tautomers of
ganaxolone. 
 1.16 “Confidential Information” means any scientific, technical, trade or business information that is
(a) given by one Party to the other and treated by the disclosing Party as confidential or proprietary, or (b) developed by or on behalf of a Party under the terms of this Agreement. The disclosing Party will, to the extent practical, use
reasonable efforts to label or identify as confidential, at the time of disclosure, all Confidential Information that is disclosed by the disclosing Party in writing or other tangible form. Notwithstanding anything to the contrary in the foregoing,
all non-public information regarding a Party’s business including all business and product plans relating to the development and commercialization of a Compound or Licensed Product, customer lists and all
agreements between a Party and any Third Party, will be considered Confidential Information, whether or not labeled as confidential. Notwithstanding the foregoing, the Exclusively Licensed Know-How and the
Lapsed Patents, to the extent relating to V134444, and to the extent not generally available to the public as of the Effective Date, will be deemed the Confidential Information of Licensee, and for purposes of Section 8.1, Licensee shall be
deemed the “disclosing Party” and Licensor shall be deemed the “receiving Party” with respect thereto, provided, however, that the confidentiality obligations and use restrictions with respect thereto shall end upon expiration or
termination of the rights granted to Licensee under Section 2.1 of this Agreement. 
 1.17 “Control” or
“Controlled” means, with respect to an item or right, the possession, whether by ownership or license (in each case other than pursuant to this Agreement), by a Party of the right to grant to the other Party access to or a license
to or under each such item or right as provided in this Agreement without violating any agreement or other arrangement with any Third Party. 

  
 3 

 1.18 “Cover”, “Covers” or
“Covered” means, with respect to a product, that in the absence of a license granted under a Valid Claim of a Patent, the making, using, selling, importation, or exportation of such product would infringe such Valid Claim (or, in
the case of a Valid Claim that has not yet issued, would infringe such Valid Claim if it were to issue) or that in the absence of a license granted under Know-How, the making, using, selling, importation, or
exportation of such product would constitute a misappropriation of such Know-How. 
 1.19
“EMA” means the European Medicines Agency, or any successor agency with similar responsibilities. 
 1.20
“Exclusively Licensed Know-How” means all Know-How Controlled by Licensor relating solely and exclusively to the Compounds, that is listed in
the Technology Transfer Plan or otherwise transferred to Licensee pursuant to this Agreement. For clarity, Exclusively Licensed Know-How includes any and all INDs for Licensor’s V134444 product and Lapsed
Patents. For further clarity, Exclusively Licensed Know-How excludes any and all Know-How Controlled by Licensor that relates to ganaxolone. 

1.21 “FDA” means the United States Food and Drug Administration, or any successor agency with similar responsibilities.

 1.22 “FFDCA” means the United States Federal Food, Drug and Cosmetic Act, as amended from time to time, including
all regulations promulgated thereunder. 
 1.23 “Field” means all fields of use. 

1.24 “First Commercial Sale” means the first arm’s length commercial sale for monetary value by Licensee or its
Related Parties of a Licensed Product in the Territory for end use or consumption by the general public of such Licensed Product in any country following receipt of Regulatory Approval in such country; provided, that First Commercial Sale does not
include: (a) any sales to or between Related Parties of Licensee; (b) any use of such Licensed Product in clinical trials, pre-clinical trials or other development activities; or (c) the
disposal or transfer of such Licensed Product for a bona fide charitable purpose. 
 1.25 “Fully-Diluted Basis”
means, as of a specified date, the number of shares of Common Stock then-outstanding plus the number of shares of common stock of Licensee issuable upon exercise or conversion of then-outstanding convertible securities or warrants, options, or other
rights to subscribe for, purchase or acquire from Licensee any capital stock of Licensee (which shall be determined without regard to whether such securities or rights are then vested, exercisable or convertible); provided that, for clarity,
“other rights to subscribe for, purchase or acquire” shall not include (i) preemptive or other rights to participate in new offerings of securities by Licensee, (ii) obligations under a purchase agreement for preferred stock of
Licensee to acquire additional shares of such preferred stock on the pre-agreed terms upon the passage of time or meeting (or waiver) of specified Licensee performance conditions, provided that, for clarity,
upon purchase or acquisition all such shares of preferred stock shall be outstanding and included in the calculation of “Fully-Diluted Basis” for purposes of the Agreement, (iii) anti-dilution provisions that have not been triggered
and (iv) anti-dilution provisions that would not be triggered by the issuance of equity securities to Licensor pursuant to or in connection with the provisions of this Agreement. 

1.26 “GAAP” means generally accepted accounting principles of the United States or any other accounting principles
mutually agreed upon by the Parties. 
 1.27 “IFRS” means the International Financial Reporting Standards. 

  
 4 

 1.28 “IND” means (a) an Investigational New Drug Application as
defined in the FFDCA and applicable regulations promulgated by the FDA, or (b) an equivalent application to the equivalent agency in any other country or group of countries, the filing of which is necessary to commence clinical testing of a
pharmaceutical product in humans in a particular jurisdiction. 
 1.29 “Indemnify” has the meaning set forth in
Section 7.1. 
 1.30 “IPO” means an underwritten initial public offering of Common Stock of Licensee pursuant to
a registration statement on Form S-1, declared effective by the SEC resulting in all outstanding preferred stock in Licensee being converted to common stock. 

1.31 “Joint Inventions” has the meaning set forth in Section 5.1. 

1.32 “Joint Patents” has the meaning set forth in Section 5.1. 

1.33 “Know-How” means any and all commercial, technical, regulatory, scientific
and other know-how and information, knowledge, technology, materials, methods, processes, practices, standard operating procedures, formulae, instructions, skills, techniques, procedures, assay protocols,
experiences, ideas, technical assistance, designs, drawings, assembly procedures, specifications, regulatory filings, data and results (including biological, chemical, pharmacological, toxicological, pharmaceutical, physical and analytical, pre-clinical, clinical, safety, regulatory, manufacturing and quality control data and know-how, including study designs and protocols and all data and information used in
support of the V134444 IND), whether or not confidential, proprietary or patentable, in written, electronic or any other form. 
 1.34
“Lapsed Patents” means the patent applications listed on Exhibit A. 
 1.35 “Licensed Intellectual
Property” means all Exclusively Licensed Know-How, Non- Exclusively Licensed Know-How and Lapsed Patents. 

1.36 “Licensed Products” means all products incorporating or comprising a Compound, including any and all formulations
and for any and all modes of administration. 
 1.37 “Licensor Improvements” means all Patents outside the field of
pain Controlled by Licensor or its Affiliates at any time during the Term that (a) are necessary for the development, manufacture or commercialization of a Compound as a single agent (b) Cover a method of use of a Compound as a single
agent, or (c) Cover a method of delivery, formulation or manufacture of a Compound as a single agent necessary for the development, manufacture or commercialization of a Compound as a single agent. 

1.38 “Licensor Indemnitees” has the meaning set forth in Section 7.1. 

1.39 “Losses” has the meaning set forth in Section 7.1. 

1.40 “Major Market Country” means any of France, Germany, Italy, Spain, and the United Kingdom. 

1.41 “MHLW” means the Ministry for Health, Labor and Welfare in Japan, or any successor agency with similar
responsibilities. 
 1.42 “NDA” means a new drug application (as such term is used under the FFDCA), a biologic
license application (as such term is used under the FFDCA), or other applicable pharmaceutical, biologic, or device approval submission to the FDA for Regulatory Approval (or, in a country other than the United States, the equivalent necessary
submissions to the applicable regulatory authority for Regulatory Approval). 

  
 5 

 1.43 “Net Sales” means the gross invoiced sales of Licensed Products
by Licensee and its Related Parties to Third Parties (other than a Sublicensee), less the following deductions to the extent specifically relating to sales of such Licensed Products: 

(a) discounts (including trade, quantity and cash discounts) actually allowed, cash and non-cash
coupons, retroactive price reductions, and charge-back payments and rebates granted to any non-Sublicensee Third Party (including to governmental entities or agencies, hospital buying groups, group purchasing
organizations and other purchasers, reimbursers, customers, distributors, wholesalers, and group purchasing and managed care organizations or entities (and other similar entities and institutions)); 

(b) credits or allowances given, if any, including on account of price adjustments, recalls, claims, damaged goods, rejections or returns of
items previously sold (including Licensed Products returned in connection with recalls or withdrawals); 
 (c) amounts written off by reason
of uncollectible debt provided such amounts do not reduce the calculation of Net Sales by more than [***], and provided that if the debt later is paid, the corresponding amount will be added to the Net Sales of the period during which it is paid;

 (d) rebates (or their equivalent) granted and similar payments made, administrative fees, distribution fees and similar fees granted or
paid by Licensee or its Related Parties (including to governmental authorities, hospital buying groups, group purchasing organizations and other purchasers, reimbursers, customers, distributors, wholesalers, and managed care organizations and
entities (and other similar entities and institutions)); 
 (e) insurance, customs charges, freight, postage, shipping, handling, and other
transportation costs incurred by Licensee or any of its Related Parties in shipping Licensed Products to a non-Sublicensee Third Party and included in the invoiced price of such Licensed Products; and 

(f) import taxes, export taxes, excise taxes (including pharmaceutical excise taxes (such as those imposed by the United States Patient
Protection and Affordable Care Act of 2010 (Pub. L. No. 111-48) and other comparable laws)), sales taxes, value-added taxes, consumption taxes, duties or other taxes directly related to such sales, to the extent that such taxes are included in
the gross invoice price of the Licensed Product and actually borne by Licensee or its Related Parties without reimbursement from any Third Party, but excluding income taxes and other taxes assessed against the income derived from such sale,
withholding taxes, net profit taxes and franchise taxes of any kind. 
 Such amounts shall be determined from the books and records of
License and its Related Parties, maintained in accordance with GAAP or IFRS, as applicable and consistently applied. With respect to Net Sales not denominated in U.S. Dollars, License shall convert such Net Sales from the applicable foreign currency
into U.S. Dollars in accordance with Section 3.6. 
 Net Sales shall not be imputed to (a) any use of Licensed Product in clinical
trials, pre-clinical trials or other development activities, (b) the disposal or transfer of Licensed Product for a bona fide charitable purpose, (c) the transfer of reasonable and customary
quantities of free samples of Product other than for subsequent resale or (d) any sale or transfer of Licensed Product on a named patient basis or for compassionate use, in each case at or below cost. 

  
 6 

 If Licensee or its Related Parties sells any Licensed Product in the form of a Combination
Product (defined below), Net Sales of such Combination Product for the purpose of determining the royalty due to Licensor pursuant to Section 3.4 will be calculated on a
country-by-country basis [***] in which sales of both occurred. If, on a
country-by-country basis, such Licensed Product and other active ingredient(s) in the Combination Product are not sold separately in such country so that the calculation
in the immediately prior sentence can be made, Net Sales for the purposes of determining royalties due to Licensor pursuant to Section 3.4 for the Combination Product will be [***]. In such event, Licensee shall notify Licensor of such
determination and provide Licensor with data to support such determination. Licensor shall have the right to review such determination of fair market values and, if Licensor disagrees with such determination, to notify Licensee of such disagreement
within [***] after Licensee notifies Licensor of such determination. If Licensor notifies Licensee that Licensor disagrees with such determination within such [***] period and if thereafter the Parties are unable to agree in good faith as to such
respective fair market values, then such matter shall be resolved as provided in Section 10.1. If Licensor does not notify Licensee that Licensor disagrees with such determination within such [***] period, such determination of Licensee shall
be conclusive and binding on the Parties. 
 1.44 “Next Financing” means the first round of preferred stock
financing (including if issued in combination with other securities) of Licensee after the last and final sale of Series B Preferred Stock and all obligations and rights to purchase Series B Preferred Stock have expired or been satisfied. 

1.45 “Non-Breaching Party” has the meaning set forth in Section 9.3. 

1.46 “Non-Exclusively Licensed
Know-How” means all Know-How relating to the Compounds Controlled by Licensor not falling within the above definition of Exclusively Licensed Know How, that is
listed in the Technology Transfer Plan or otherwise transferred to Licensee pursuant to this Agreement. 
 1.47 “Notified
Party” has the meaning set forth in Section 9.3. 
 1.48 “PAC” has the meaning set forth in
Section 4.3. 
 1.49 “Party” means Licensee or Licensor; “Parties” means, collectively,
Licensee and Licensor. 
 1.50 “Patent” means any United States or foreign (i) unexpired letters patent
(including inventor’s certificates) which have not been held invalid or unenforceable by a court of competent jurisdiction from which no appeal can be taken or has been taken within the required time period, including any substitution,
extension, registration, confirmation, reissue, re-examination, renewal or any like filing, and (ii) pending applications for letters patent, including any provisional, converted provisional, continued
prosecution application, continuation, divisional or continuation-in-part. 

1.51 “Phase 2 Clinical Trial” means, as to a specific Licensed Product, a human clinical trial in any country
that is intended to preliminarily evaluate the efficacy and safety or dose-ranging of such product for a particular indication or indications in patients with the disease or indication under study or would otherwise satisfy requirements of 21 CFR
312.21(b) in the United States, as amended from time to time, or the corresponding regulation in jurisdictions other than the United States. 

1.52 “Phase 3 Clinical Trial” means, as to a specific Licensed Product, (a) a human clinical trial in any country
that is performed to obtain Regulatory Approval of such product after preliminary evidence suggesting effectiveness of such product under evaluation has been obtained, and intended to confirm with statistical significance the efficacy and safety of
such product, to evaluate the overall benefit-

  
 7 

 
risk relationship of such product and to provide an adequate basis for physician labeling, or (b) a human clinical trial of such product that satisfies the requirements of 21 C.F.R. §
312.21(c) in the United States, as amended from time to time, or the corresponding regulation in jurisdictions other than the United States. 

1.53 “Praxis” and “Licensee” both mean Praxis Precision Medicines, Inc., a Delaware
corporation. 
 1.54 “Prior Confidentiality Agreement” means that certain confidentiality letter agreement by and
between Licensee and Purdue Pharma L.P. dated as of December 14, 2017. 
 1.55 “Qualified Financing” means the
first to occur of (i) a financing of Licensee after the Effective Date with aggregate gross proceeds received of not less than [***], or such lesser amount as agreed upon by Licensor, from the sale (or series of related sales) by Licensee of
its Series B Preferred Stock, including the aggregate amount of debt securities converted into equity securities upon conversion of any then outstanding promissory notes or other instruments of similar tenor, but exclusive of the conversion of any
promissory notes or other instruments of similar tenor outstanding on and as of the Effective Date, or (ii) an IPO. 
 1.56
“Qualified Financing Date” means May 1, 2018, provided that, Licensor may elect, upon written notice to Licensee given no later than five (5) Business Days prior to May 1, 2018, to extend such date to June 1,
2018, in which case the term “Qualified Financing Date” shall be deemed amended, without further action of the Parties, to mean June 1, 2018. 

1.57 “Regulatory Approval” means, as applicable, (i) with reference to the United States, the approval of an NDA
by the FDA necessary for the manufacture and commercialization of a pharmaceutical, biologic or device product in the United States, (ii) with reference to the European Union and/or United Kingdom, the approval of an NDA by the EMA or the
European Commission filed pursuant to the centralized approval procedure and necessary for the manufacture and commercialization of a pharmaceutical, biologic or device product in the European Union and/or United Kingdom, (iii) with reference
to a Major Market Country, the approval of an NDA by the applicable regulatory authority in such Major Market Country (when such NDA has been separately filed with such regulatory authority and not as part of the centralized approval procedure of
the EMA or the European Commission) and necessary for the manufacture and commercialization of a pharmaceutical, biologic or device product in such Major Market Country, and (iv) with reference to Japan, the approval of an NDA by the MHLW
necessary for the manufacture and commercialization of a pharmaceutical, biologic or device product in Japan, including in each case of the preceding clauses (i) through (iv), any applicable pricing and governmental reimbursement approvals
legally or practically required to manufacture and commercialize such product in such country or jurisdiction 
 1.58
“Regulatory Exclusivity” means any exclusive marketing rights or data protection or other exclusivity rights conferred by any regulatory authority with respect to a Licensed Product in a country or jurisdiction in the Territory,
including but not limited to orphan drug or pediatric exclusivity. 
 1.59 “Regulatory Filings” has the meaning set
forth in Section 4.4(b). 
 1.60 “Related Party” means Licensee’s Affiliates and Sublicensees. 

1.61 “Reporting Period” shall mean (a) during the period prior to the first Change of Control of Praxis, as
Licensee hereunder, [***] and (b) on and after the first Change of Control of Praxis, as Licensee hereunder, [***], provided that in each case of (a) and (b), such period shall be extended by an additional [***] for the reporting
and payment of royalties on Net Sales made by Sublicensee. 

  
 8 

 1.62 “Royalty Term” has the meaning set forth in
Section 3.4(b). 
 1.63 “SAB” has the meaning set forth in Section 3.3(f). 

1.64 “Safety Determination” means: (a) a good faith determination by the Board that, based at least in part on the
occurrence or observation of a Safety Issue, the Licensed Product presents a risk of death, a life-threatening condition or a serious safety or health concern to patients such that Licensee cannot ethically and in good faith continue to administer,
or permit the administration of, the Licensed Product to patients; (b) a data safety monitoring board has recommended the termination of any clinical trial of the Licensed Product after the occurrence or observation of a Safety Issue;
(c) the FDA or other applicable regulatory authority has issued a clinical hold, or otherwise required or recommended termination or suspension of, any clinical trial of the Licensed Product after the occurrence or observation of a Safety
Issue; or (d) a good faith determination by the Board that based on the occurrence or observation of a Safety Issue, and taking into account all other relevant factors, the continued development and possible commercialization of the Licensed
Product is not commercially reasonable for Licensee. 
 1.65 “Safety Issue” means a serious adverse event,
toxicology finding or other serious safety issue or tolerability finding or issue with respect to a Licensed Product administered to humans that, as of the Effective Date, was not publicly known to be an adverse event, toxicology finding or other
safety or tolerability finding or issue associated with positive allosteric modulators of GABA-A, as a class. 

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

1.67 “Series A Preferred Stock” means the Series A Convertible Preferred Stock of Licensee, $0.0001 par value per
share. 
 1.68 “Series A Preferred Stock Transaction Agreements” has the meaning set forth in Section 3.3(b).

 1.69 “Series B Preferred Stock” means the Series B Convertible Preferred Stock of Licensee, $0.0001 par value per
share. 
 1.70 “Series B Preferred Stock Transaction Agreements” has the meaning set forth in Section 3.3(a).

 1.71 “Series X Preferred Stock” means the Series A Preferred Stock and/or Series B Preferred Stock. 

1.72 “Shares” means the aggregate number of shares of Common Stock issuable or issued upon conversion of the Series X
Preferred Stock issued to Licensor pursuant to the terms of Section 3.3(a), Section 3.3(b), Section 3.3(c) and Section 3.3(d), without taking into account any sales or transfers of any such shares by Licensor after the date of
issuance of the Series X Preferred Stock in accordance with the terms of this Agreement. 
 1.73 “Sublicensee”
means an entity to which Licensee grants a sublicense under Licensee’s rights under Article 2; provided that “Sublicensee” does not include any of Licensee’s Affiliates or wholesale distributors of Licensee or its
Affiliates who purchase Licensed Products from Licensee or its Affiliates in an arm’s length transaction and who have no other obligation, including a reporting obligation, to Licensee or its Affiliates, with respect to any subsequent use or
disposition of such Licensed Products. 
 1.74 “Technology Transfer Plan” has the meaning set forth in
Section 4.1 

  
 9 

 1.75 “Term” has the meaning set forth in Section 9.1. 

1.76 “Territory” means all the countries and territories of the world. 

1.77 “Third Party” means any entity other than Licensor, Licensee and their respective Affiliates. 

1.78 “Third Party Agreements” means any contract, agreement, arrangement or understanding, written or oral, with a
Third Party with respect to any Licensed Intellectual Property, other than material transfer agreements, sponsored research agreements or similar agreements entered into in the ordinary course of business that do not provide for the payment of any
milestones, royalties or other fees or charges with respect to the Compounds or Licensed Products that may be researched, developed or commercialized by Licensee or its Related Parties in accordance with the terms of this Agreement. 

1.79 “Third Party Claim” has the meaning set forth in Section 7.1. 

1.80 “V134444” means the GABA-A Positive Allosteric Modulator designated as
V13444 by Licensor, as further described on Schedule 1.80. 
 1.81 “V134444 IND” means the IND for Licensor’s
V134444 product, as further described on Schedule 1.81. 
 1.82 “Valid Claim” means (a) an issued claim of any issued
patent within a patent that has not expired, or been revoked, cancelled, become abandoned or disclaimed, been declared invalid and/or unenforceable by a patent office or a decision or judgment of a court or other appropriate body of competent
jurisdiction; and (b) a claim included in a pending patent application that is being prosecuted in good faith and that has not been cancelled, withdrawn from consideration, finally determined to be unallowable by the patent office or applicable
governmental authority (from which no appeal is or can be taken), or abandoned or disclaimed. 
 1.83 “Withholding Tax
Action” means an assignment of all or any portion of this Agreement by Licensee, change of control of Licensee, change of jurisdiction of payments by Licensee, or change of domicile by Licensee that causes a withholding Tax obligation to arise
or which increases a withholding Tax obligation with respect to an amount payable to Licensor pursuant to this Agreement, except to the extent a Change of Control of Licensee or change of domicile of Licensee is caused by the direct or indirect
ownership of Licensee by Licensor or any of Licensor’s direct or indirect owners. 
 ARTICLE 2 

GRANT OF RIGHTS 
 2.1
License Grant to Licensee. 
 (a) Exclusive License. Subject to the terms and conditions of this Agreement, Licensor hereby grants
to Licensee an exclusive, royalty-bearing license, with the right to grant sublicenses (subject to the provisions of Section 2.1(d) below), in the Territory to and under the Exclusively Licensed Know-How
to research, develop, make, have made, use, have used, sell, have sold, offer for sale, import and export Licensed Products in the Field. 

(b) Non-Exclusive License. Subject to the terms and conditions of this Agreement, Licensor
hereby grants to Licensee a non-exclusive, royalty-bearing license, with the right to grant sublicenses (subject to the provisions of Section 2.1(d) below), in the Territory to and under the Non- Exclusively Licensed Know-How to research, develop, make, have made, use, have used, sell, have sold, offer for sale, import and export Licensed Products in the Field.

  
 10 

 (c) Unblocking License. Subject to the terms and conditions of this Agreement,
Licensor hereby grants to Licensee a non-exclusive, royalty-free license in the Territory, with the right to grant sublicenses (subject to the provisions of Section 2.1(d) below), under the Licensor
Improvements to research, develop, make, have made, use, have used, sell, offer for sale, import and commercialize Licensed Products in the Field. Notwithstanding the foregoing license grant, Licensor shall have no obligations to transfer to
Licensee any such Licensor Improvements. 
 (d) Sublicenses. Each sublicense granted pursuant to Section 2.1 shall refer to and
be subordinate to this Agreement and, except to the extent the Parties may otherwise agree in writing, any sublicense must be consistent in all material respects with the terms and conditions of this Agreement. Licensee shall remain responsible for
the performance of Related Parties hereunder. Licensee shall provide to Licensor copies of all sublicenses, provided that Licensee shall have the right to redact commercially sensitive information (including financial and technical information) from
such copies. Information regarding the scope of the license grants, territory and/or term of such sublicense shall not be considered commercially sensitive. Sublicenses of rights under Section 2.1(c) may not be granted without Licensor’s
prior written consent, which consent shall not be unreasonably withheld, conditioned, or delayed. To the extent consent is granted by Licensor for a sublicense under Section 2.1(c), the first three sentences of Section 2.1(d) shall apply
to such sublicense. 
 2.2 No Implied Licenses. Except as expressly set forth in this Agreement, neither Party grants any licenses
under its intellectual property rights to the other Party, including, in the case of Licensor, the grant to Licensee of a license to any compounds or products other than a Compound and Licensed Products. 

ARTICLE 3 
 COMPENSATION

 3.1 [Reserved] 

3.2 Milestone Payments. 

(a) Development Milestones. In partial consideration of the rights granted hereunder, Licensee will make milestone payments to Licensor
based on the first achievement of the following development milestone events by Licensee or its Related Parties. Licensee will notify Licensor in writing of the achievement of each of the development milestone events listed below and pay to Licensor
the amounts set forth below within [***] after achievement of the relevant milestone event for a Licensed Product by Licensee or its Affiliate or, if applicable, within [***] after Licensee is notified of the achievement of the relevant milestone
event for a Licensed Product by a Sublicensee. Each of the following milestone payments will be payable only once and solely with respect to the first Licensed Product in the Territory to achieve each such milestone. The maximum total amount of
payment to Licensor pursuant to this Section 3.2(a) shall be [***]. Each milestone payment will be nonrefundable and not creditable against any other payments due under this Agreement. 

 

					
	 Development Milestone Events
	  	Payment Amount	 
	 [***]
	  	 	[	***] 
	 [***]
	  	 	[	***] 
	 [***]
	  	 	[	***] 
	 [***]
	  	 	[	***] 

  
 11 

 (b) Sales Milestones. In partial consideration of the rights granted hereunder,
Licensee will make milestone payments to Licensor on achievement of the following sales milestone events by Licensee or its Related Parties. Licensee will notify Licensor in writing of the achievement of each of the sales milestone events listed
below and pay to Licensor the amounts set forth below within [***] of Licensee’s or its Affiliate’s achievement of the relevant milestone event, or, if achievement is dependent upon notification by or reports from a Sublicensee, then
within [***] after Licensee has been notified of the achievement of the relevant milestone event by a Sublicensee or received the necessary reports from its Sublicensees to determine whether such achievement has occurred. Each of the following
milestone payments will be payable only once and solely with respect to the first Licensed Product in the Territory to reach each such milestone. The maximum total amount of payment to Licensor pursuant to this Section 3.2(b) shall be [***].
Each milestone payment will be nonrefundable and not creditable against any other payments due under this Agreement. 
  

					
	 Sales Milestone Events for Licensed Products
	  	Payment Amount	 
	 First Commercial Sale of a Licensed Product in [***]
	  	 	[	***] 
	 Worldwide aggregate Net Sales of all Licensed Products in a Calendar Year exceeds [***]
	  	 	[	***] 
	 Worldwide aggregate Net Sales of all Licensed Products in a Calendar Year exceeds [***]
	  	 	[	***] 
	 Worldwide aggregate Net Sales of all Licensed Products in a Calendar Year exceeds [***]
	  	 	[	***] 

 3.3 Equity; Board Representation. 

(a) Mandatory Series B Preferred Stock Issuance. Subject to and upon the terms and conditions of this Agreement, Licensee shall issue
and sell to Licensor, and Licensor shall purchase from Licensee, [***] of Licensee’s duly authorized and validly issued shares of Series B Preferred Stock at the closing of a Qualified Financing (other than an IPO) occurring before the
Qualified Financing Date on substantially the same terms and conditions as offered to other purchasers of Series B Preferred Stock in such Qualified Financing. Licensor shall, as a condition to such issuance and sale, become a party to a stock
purchase agreement, voting agreement, right of first refusal and co-sale agreement, and investors’ rights agreement (collectively, such agreements other than such stock purchase agreement, the
“Series B Preferred Stock Transaction Agreements”) with Licensee and the other purchasers of Series B Preferred Stock in such Qualified Financing on substantially the same terms and conditions as such other purchasers,
provided that any information and inspection rights of Licensor may be qualified by reasonable and customary provisions relating to competitors of Licensee and provided further that any right of Licensor to transfer the Shares to any
person or entity that is a competitor of Licensee, or is an Affiliate of a competitor of Licensee, shall require the consent of the Board, which may be conditioned on reasonable and customary terms. In the event that immediately following the
closing of the purchase of Series B Preferred Stock by Licensor in accordance with this Section 3.3(a) the Series B Preferred Stock purchased by Licensor would represent less than [***] of Licensee’s outstanding capital stock on a Fully
Diluted Basis, Licensee shall issue to Licensor at such closing of the Qualified Financing, for no additional consideration, such additional 

  
 12 

 
number of shares of Series B Preferred Stock such that the shares of Series B Preferred Stock purchased by Licensor plus such additional number of shares of Series B Preferred Stock would then
represent in the aggregate [***] of Licensee’s outstanding capital stock on a Fully-Diluted Basis, as calculated after giving effect to such anti-dilutive issuance. All shares of Series B Preferred Stock issued to Licensor pursuant to
Section 3.3(c) shall become subject to the terms and conditions of the Series B Preferred Stock Transaction Agreements. 
 (b) Series
A Preferred Stock Issuance. In the event that a Qualified Financing has not occurred before the Qualified Financing Date (and Licensor has not sent and does not send a notice of termination under Section 9.2(c)), Licensor shall have the
right, but not the obligation, to purchase from Licensee, for the sum of [***], a number of shares of Licensee’s duly authorized and validly issued shares of Series A Preferred Stock representing in the aggregate [***] of Licensee’s
outstanding capital stock on a Fully-Diluted Basis, as calculated immediately following the closing of such issuance and sale (but in the case of such issuance and sale in connection with a Qualified Financing (other than an IPO), without giving
effect to any issuance and sale of Series B Preferred Stock in consideration for cash investment in such Qualified Financing), on substantially the same terms and conditions (except with respect to price) as had been offered to the other purchasers
of such Series A Preferred Stock at the most recent closing of the purchase of sale of Series A Preferred Stock prior to the Effective Date. Licensor may exercise such right, upon written notice of exercise to Licensee, at any time within the
exercise period commencing on the Qualified Financing Date and ending on the earliest of (i) the [***] of the Qualified Financing Date, (ii) immediately prior to the closing of a Qualified Financing (other than an IPO), and (iii) [***]
after Licensee files with the SEC a Form S-1 registering for sale any securities issued by Licensee or Licensee submits with the SEC a draft registration statement on Form
S-1 registering for sale any securities issued by Licensee, in each case with a bona fide intention for the registration statement to become effective and to consummate the closing of an IPO, provided,
however, in the case of this clause (iii), if the IPO is not consummated within [***] following the filing or submission of the Form S-1, (A) such Licensor notice of exercise shall not be binding on Licensor,
(B) the exercise period shall not be terminated as a result of the operation of this clause (iii) as a result of such written notice and (C) the terms of this clause (iii) shall apply to any subsequent such filing or submission
(including any amendment filed or submitted with respect to a prior filing or submission). The closing of such issuance and sale shall occur by remote exchange of documents on a Business Day and at a time reasonably chosen by Licensee, but no later
than fifteen (15) Business Days after notice of exercise by Licensor, or such later date as all requisite corporate approvals of Licensee have been obtained, in the case of clauses (i) and (ii) above, and no later than [***] prior to the
closing of the IPO, in the case of clause (iii) above. At the closing, Licensee shall issue and sell to Licensor such shares of Series A Preferred Stock, and Licensor shall purchase such shares of Series A Preferred Stock and, as a condition to
such issuance and sale, become a party to a stock purchase agreement, voting agreement, right of first refusal and co-sale agreement, and investors’ rights agreement (collectively, such agreements other
than such stock purchase agreement, the “Series A Preferred Stock Transaction Agreements”) with Licensee and the other purchasers of Series A Preferred Stock on substantially the same terms and conditions as such other purchasers,
provided that any information and inspection rights of Licensor may be qualified by reasonable and customary provisions relating to competitors of Licensee and provided further that any right of Licensor to transfer the Shares to any
person or entity that is a competitor of Licensee, or is an Affiliate of a competitor of Licensee, shall require the consent of the Board, which may be conditioned on reasonable and customary terms. If, in connection with the issuance and sale of
Series A Preferred Stock to Licensor pursuant to this Section 3.3(b) in connection with a Qualified Financing (other than an IPO), such shares of Series A Preferred Stock purchased by Licensor in accordance with this Section 3.3(b) would
represent less than [***] of Licensee’s outstanding capital stock on a Fully Diluted Basis after such Qualified Financing, Licensee shall issue to Licensor at such closing of the Qualified Financing, for no additional consideration, such
additional number of shares of Series A Preferred Stock such that the shares of Series A Preferred Stock purchased by Licensor plus such additional number of shares of Series A Preferred Stock would then represent in the aggregate [***] of
Licensee’s outstanding 

  
 13 

 
capital stock on a Fully-Diluted Basis, as calculated after giving effect to such anti-dilutive issuance. All shares of Series A Preferred Stock issued to Licensor pursuant to Section 3.3(c)
shall become subject to the terms and conditions of the Series A Preferred Stock Transaction Agreements. Licensee agrees that, if it is required to issue shares of Series A Preferred Stock to Licensor in accordance with the terms of this
Section 3.3(b), it will take, or cause to be taken, all corporate actions required to effectuate such issuance, including required amendments to Licensee’s Certificate of Incorporation, and will not issue additional shares of equity
securities (other than shares issuable upon exercise of outstanding options, warrants or convertible securities) without first taking all corporate actions, and obtaining all required Board and shareholder approvals, necessary to effectuate the
issuance of such shares of Series A Preferred Stock to Licensor. 
 (c) Optional Series B Preferred Stock Issuance. In the event that
a Qualified Financing has not occurred before the Qualified Financing Date (and Licensor has not sent and does not send a notice of termination under Section 9.2(c)), in lieu of (and not in addition to) Licensor’s right to purchase Series
A Preferred Stock from Licensee pursuant to the terms of Section 3.3(b), Licensor shall have the right, but not the obligation, to purchase from Licensee at the closing of a Qualified Financing (other than an IPO), for the sum of [***], that
number of shares of Licensee’s duly authorized and validly issued shares of Series B Preferred Stock representing in the aggregate [***] of Licensee’s outstanding capital stock on a Fully-Diluted Basis, as calculated immediately following
the closing of such issuance and sale, on the same terms and conditions set forth in Section 3.3(a). Licensor may exercise such right, upon written notice of exercise to Licensee, at any time within the exercise period commencing on the
Qualified Financing Date and ending on the earlier of (i) the [***] of the Qualified Financing Date, and (ii) immediately prior to the closing of a Qualified Financing (other than an IPO). All shares of Series B Preferred Stock issued to
Licensor pursuant to Section 3.3(c) shall become subject to the terms and conditions of the Series B Preferred Stock Transaction Agreements. In the event that immediately following the closing of the purchase of Series B Preferred Stock by
Licensor in accordance with this Section 3.3(c) the Series B Preferred Stock purchased by Licensor would represent less than [***] of Licensee’s outstanding capital stock on a Fully Diluted Basis, Licensee shall issue to Licensor at such
closing of the Qualified Financing, for no additional consideration, such additional number of shares of Series B Preferred Stock such that the shares of Series B Preferred Stock purchased by Licensor plus such additional number of shares of Series
B Preferred Stock would then represent in the aggregate [***] of Licensee’s outstanding capital stock on a Fully-Diluted Basis, as calculated after giving effect to such anti-dilutive issuance. 

(d) Additional Series X Preferred Stock Issuances. If, at any time, after the purchase of Series X Preferred Stock by Licensor in
accordance with Section 3.3(a), 3.3(b) or 3.3(c), as applicable, and prior to the first closing of the Next Financing, Licensee issues Additional Securities that would cause the Shares to represent less than [***] of Licensee’s outstanding
capital stock on a Fully-Diluted Basis, Licensee shall immediately issue to Licensor, for no additional consideration, such additional number of shares of the same series of Series X Preferred Stock as were purchased by Licensor (the
“Anti-Dilution Shares”) such that the Shares (calculated immediately prior to such issuance), plus the Anti-Dilution Shares would then represent in the aggregate [***] of Licensee’s outstanding capital stock on a Fully-Diluted
Basis, as calculated after giving effect to such anti-dilutive issuance. Licensee shall as promptly as reasonably practicable following any trigger of issuance of Anti-Dilution Shares furnish to Licensor a certificate of an executive officer
certifying the calculation thereof and deliver to Licensor such Anti-Dilution Shares; provided, however, that to the extent such Additional Securities are issued pursuant to an equity incentive plan, Licensee shall provide such certificate and issue
such Anti-Dilution Shares upon the earlier of (a) [***] after the end of the Calendar Quarter in which the issuances took place and (b) the closing of the next equity financing of Licensee, together with details of all Additional Securities
issuances pursuant to an equity plan following the first trigger of issuances of Anti-Dilution Shares. Such issuances shall continue only up to, and immediately prior to the first closing of the Next Financing and, thereafter, no additional shares
of capital stock of Licensee shall be due to Licensor pursuant to this Section 3.3(c); 

  
 14 

 
provided, however that notwithstanding the foregoing or anything to the contrary elsewhere in the Agreement, any and all issuances and sales of Series B Preferred Stock at or after the first
closing of the Next Financing shall be treated as having been issued and sold prior to the first closing of the Next Financing for all purposes of this Agreement. Licensee agrees that, if it is required to issue shares of Series X Preferred Stock to
Licensor in accordance with the terms of this Section 3.3(c), it will take, or cause to be taken, all corporate actions required to effectuate such issuance, including required amendments to Licensee’s Certificate of Incorporation, and
will not issue additional shares of equity securities (other than shares issuable upon exercise of outstanding options, warrants or convertible securities) without first taking all corporate actions, and obtaining all required Board and shareholder
approvals, necessary to effectuate the issuance of such shares of Series X Preferred Stock to Licensor. 
 (e) Information. In
addition to Licensee’s obligations pursuant to Section 3.3(c) above and any Licensee information obligations pursuant to the Series A Preferred Stock Transaction Agreements or Series B Preferred Stock Agreements, as applicable, to which
Licensor may become a party, upon request, but no more frequently than [***] per Calendar Quarter, Licensee will deliver to Licensor a statement of the outstanding capital stock of Licensee on a Fully-Diluted Basis and a detailed calculation of
Licensor’s percentage equity ownership in Licensee. The obligation in this Section 3.3(e) shall cease upon the first closing of the Next Financing. 

(f) Board Member; SAB Member. For so long as Licensor or an Affiliate holds of record either (i) at least [***] of the shares of
Series X Preferred Stock issued to Licensor in accordance with Sections 3.3(a), 3.3(b), 3.3(c) or 3.3(d), as applicable (as adjusted for any stock split, stock dividend, combination, recapitalization or reclassification), provided that any shares
issued in accordance with Section 3.3(d) that are converted to Common Stock in accordance with Section 3.3(g) shall not be considered in making the foregoing calculation of the percentage of shares of Series X Preferred Stock held of
record, or (ii) at least [***] of Licensee’s outstanding capital stock on a Fully-Diluted Basis, Licensor shall have the right to appoint (i) one (1) representative to serve as a voting member of the Board, subject to the provisions
of this Agreement and the applicable Series A Preferred Stock Transaction Agreements or Series B Preferred Stock Agreements, as applicable, to which Licensor may become a party, and (ii) one (1) representative to serve as a member of
Licensee’s Scientific Advisory Board (the “SAB”). Such representatives shall agree to hold in confidence and trust and to act in a fiduciary manner with respect to all information provided in connection with such representation
and shall, as a condition to their attendance at meetings of the Board or the SAB, as applicable, and receipt of information and materials hereunder, sign a confidentiality agreement with Licensee in such form as Licensee may reasonably request. In
addition, as a condition to his or her appointment to and participation on the SAB, Licensor’s designee to the SAB shall enter into a customary scientific advisory board agreement with Licensee on terms mutually agreeable to Licensee and such
designee, provided that he or she will not be eligible to receive any compensation for his or her services as a member of the SAB. Licensor’s Board and SAB representatives shall be entitled to and receive the same indemnification, D&O
insurance, meeting attendance out-of-pocket expenses, compensation (except to the extent provided in the preceding sentence for Licensor’s designee to the SAB) and
other rights and benefits as other non-employee Licensee Board and SAB members. 
 (g)
Observer. As of the Effective Date and until the earlier of (i) a Qualified Financing or (ii) immediately prior to the closing of the first Change of Control of Praxis, Licensee hereby agrees that Licensor may designate in writing
one representative who will be entitled to attend and observe meetings of the Board in a non-voting observer capacity (the “Observer”). The Observer will initially be
[                ], who may be replaced upon written notice by Licensor to the Licensee by a future designee of the Licensor reasonably acceptable to the Board. Praxis
will provide the Observer, all notices, minutes, consents, management presentations, strategic planning materials, scientific reports, routine financial reports, and other material, financial or otherwise, that Praxis provides to the Board at the
same time that such notices and materials are provided to the Board, including, for the avoidance of doubt, for ad hoc 

  
 15 

 
meetings; provided that the Observer enter into Praxis’ form of confidentiality agreement as mutually agreed to by Licensor. Licensor understands and agrees that the Observer may not attend
any portion of a Board meeting or receive certain Board materials if, on the advice of Praxis’ counsel, Observer’s participation or receipt of information (i) would create an actual conflict of interest or (ii) could reasonably
be expected to compromise attorney-client privilege. 
 (h) Conversion of Shares. In the event that Licensee elects to terminate this
Agreement pursuant to Section 9.2(a) on account of a Safety Determination at any time during the period commencing on the earlier of (A) the closing of a Qualified Financing and (B) [***] after the Effective Date and ending on the first to
occur of (X) the [***] of the Effective Date and (Y) first subject, first dosing in the first Phase 2 Clinical Trial of a Licensed Product sponsored by or on behalf of Licensee or Related Parties, the shares of Series X Preferred Stock
issued pursuant to Section 3.3(d), if any, shall be converted automatically into Common Stock upon written notice by Licensee to Licensor within [***] after the effective date of such termination. Upon receipt of such notice, Licensee hereby
irrevocably elects to convert such shares of Series X Preferred Stock into Common Stock in accordance with the terms of Licensee’s Certificate of Incorporation. Upon receipt of such notice, Licensor shall surrender its certificate or
certificates for all such shares being converted (or, if such holder alleges that any such certificate has been lost, stolen or destroyed, a lost certificate affidavit and agreement reasonably acceptable to Licensee to indemnify Licensee against any
claim that may be made against Licensee on account of the alleged loss, theft or destruction of such certificate) to Licensee at the time and place designated in such notice. If so required by Licensee, any certificates surrendered for conversion
shall be endorsed or accompanied by written instrument or instruments of transfer, in form satisfactory to Licensee, duly executed by Licensor or its attorney duly authorized in writing. All rights with respect to the shares of Series X Preferred
Stock subject to such notice of conversion, including the rights, if any, to receive notices and vote, will terminate upon such notice (notwithstanding the failure of the holder or holders thereof to surrender any certificates for such shares),
except only the rights of Licensor, upon surrender of any certificate or certificates of Licensor therefor (or lost certificate affidavit and agreement), to receive the shares of Common Stock issuable upon conversion thereof. 

(i) Termination. The rights of Licensor set forth in Sections 3.3(d), 3.3(e), 3.3(f) and 3.3(g) and the terms of Section 3.3(h)
shall terminate and be of no further force or effect (i) immediately prior to the closing of Licensee’s first IPO or (ii) provided that Licensee has complied with its obligations of Section 6.3(c), immediately prior to the
closing of the first Change of Control of Praxis, as Licensee hereunder, whichever event occurs first. 
 3.4 Royalties. 

(a) Rates. Subject to Sections 3.4(b), 3.4(c) and 3.4(d), Licensee will pay Licensor royalties based on Net Sales of Licensed Products
by Licensee and its Related Parties in a given Calendar Year during the applicable Royalty Term for such Licensed Product according to the following rates at the rate below that is applicable to the portion of aggregate Net Sales for each such
Licensed Product, on a Licensed Product-by-Licensed Product basis, within each of the following Net Sales levels during such Calendar Year: 

 

			
	 Annual Net Sales of All Licensed Products in the
Territory
	  	Royalty Rate
		
	 For that portion of aggregate Net Sales of a Licensed Product in a Calendar Year that is less than
[***]
	  	[***]
		
	 For that portion of aggregate Net Sales of a Licensed Product in a Calendar Year that is equal to
or greater than [***], but less than or equal to [***]
	  	[***]
		
	 For that portion of aggregate Net Sales of a Licensed Product in a Calendar Year that is greater
than [***]
	  	[***]

  
 16 

 For example, if aggregate annual Net Sales of a Licensed Product in the Territory in a
Calendar Year is [***], then royalties payable by Licensee would equal [***]. The Parties acknowledge and agree that nothing in this Agreement (including any exhibits or attachments to this Agreement) will be construed as representing an estimate or
projection of either (A) the number of Licensed Products that will or may be successfully developed or commercialized or (B) anticipated sales or the actual value of any Licensed Product, and that the figures set forth in this
Section 3.4 or elsewhere in this Agreement or that have otherwise been discussed by the Parties are merely intended to define the Parties’ royalty payment obligations to each other in the event such sales performance is achieved. 

(b) Royalty Term. “Royalty Term” means, on a
country-by-country and Licensed Product-by-Licensed Product basis, the period of time
beginning upon the Effective Date and ending twelve (12) years after the First Commercial Sale of such Licensed Product in such country. 

(c) Payments under Third Party Agreements. The Parties acknowledge that Licensor will remain solely liable for any payment obligations
(including license fees, milestones or royalties) under any Third Party Agreements. 
 (d) Other Royalty Provisions. Only one royalty
will be due with respect to the same unit of Licensed Product. No royalties will be due upon the sale or other transfer among Licensee and its Related Parties, but in such cases the royalty will be due and calculated upon Licensee’s or its
Related Parties’ Net Sales to the first independent Third Party. No royalties will accrue on the sale or other disposition of Licensed Products by Licensee or its Related Parties for use in a clinical study sponsored or funded by Licensee or on
the disposition of a Licensed Product in reasonable quantities by Licensee or its Related Parties as promotional samples. Any amounts awarded or received by Licensee for lost sales (including, without limitation, lost profits or reasonable
royalties) (but not any other amounts awarded) as the result of an action or settlement pursuant to Section 5.2 or 5.3 shall be deemed Net Sales of Licensee. 

3.5 Royalty Payment and Reports. Within the Reporting Period after the end of each Calendar Quarter after the First Commercial Sale of a
Licensed Product, Licensee will deliver to Licensor a report containing the following information for the prior Calendar Quarter: 
 (a) the
gross sales associated with each Licensed Product sold by Licensee and its Related Parties (including the number and size of units of Licensed Product sold by Licensee and its Related Parties); 

(b) a calculation of Net Sales of each Licensed Product that is sold by Licensee and its Related Parties (including the amount of each of the
deductions taken from gross sales); 
 (c) the amount of taxes, if any, withheld to comply with applicable law; and 

(d) a calculation of payments due to Licensor with respect to the foregoing (including any calculation of currency conversion). 

  
 17 

 Concurrent with these reports, Licensee will remit to Licensor any payment due for the applicable Calendar
Quarter. All such reports will be considered Confidential Information of Licensee and will be maintained in confidence by Licensor. If no royalties or other payments are due to Licensor for such reporting period, the report will so state. Along with
the last report for a Calendar Year provided under this Article 3, Licensee will provide a final report for the entire such year. 
 3.6
Currency; Blocked Payments. All dollar ($) amounts specified in this Agreement are United States dollar amounts and all payments to be made under this Agreement will be made in United States dollars and will be paid by bank wire transfer in
immediately available funds to such bank account in the United States as may be designated in writing by the receiving Party from time to time. In the case of sales of Licensed Products outside the United States by Licensee and its Related Parties,
the rate of exchange to be used in computing the amount of currency equivalent in United States dollars due will be made at the rate of exchange as agreed and listed in the Wall Street Journal or The Financial Times, prevailing on the
last day of the applicable Calendar Quarter, provided that for Net Sales made by a Sublicensee such rate of exchange shall be rate of exchange utilized by such Sublicensee, and for Net Sales made by Licensee or any Affiliate of Licensee from and
after the first Change of Control of Praxis, as Licensee hereunder, such rate of exchange shall be rate of exchange utilized by Licensee, provided that in all cases such rate of exchange is one consistently applied across such person’s
accounting systems, and any such method is in accordance with GAAP. Licensee shall inform Licensor of any changes to its standard worldwide currency conversion methodology prior to any such changes becoming effective. 

3.7 Tax Withholding. If Licensee is required applicable law to deduct or withhold income taxes upon Licensor from any payment to
Licensor under this Agreement, Licensee shall make such deductions or withholdings as so required, shall pay over such amounts to the proper governmental authority on Licensor’s behalf in a timely manner, and shall provide Licensor with written
evidence of payment of such amounts. The applicable payment under this Agreement shall be decreased by such amounts; provided, however, if the Tax withholding is required as a result of a Withholding Tax Action, Licensee shall increase the amount of
the payment due to the Licensor such that the net amount actually received by Licensor is equal to the payment due after taking into account the withholding of tax with respect to such payment and the withholding of tax with respect to any
additional payment required to be made pursuant to this Section 3.7. The Parties shall reasonably cooperate with each other in order to reduce or eliminate applicable withholding tax, including by providing such forms the Parties are legally
able to complete and file to qualify for the benefits of a bilateral income tax treaty. 
 3.8 Records and Audits. Licensee will keep,
and will require all its Related Parties to keep, correct and complete books of accounts and other records containing all information and data which may be necessary to ascertain and verify the royalties payable under this Agreement. During the Term
and for a period of [***] following its termination, Licensor has the right from time to time (not to exceed once during each Calendar Year, except in case of manifest error) to have an independent certified public accountant inspect such books and
records of Licensee and/or its Related Parties at Licensor’s expense. Such inspection will be conducted after reasonable prior notice by Licensor to Licensee during Licensee’s ordinary business hours, will not be more frequent than [***]
during each Calendar Year and may cover only the [***] immediately preceding the date of the audit, except in case of manifest error. Any such independent certified accountant will be reasonably acceptable to Licensee, will execute Licensee’s
standard form of confidentiality agreement, and will be permitted to share with Licensor solely its findings with respect to the accuracy of the royalties reported as payable under this Agreement. The independent certified accountant will report to
the Parties whether there was or was not a discrepancy uncovered by the audit and, if such discrepancy was uncovered, the amount and direction of such discrepancy. If such accounting firm determines that Licensee paid Licensor less than the amount
properly due in respect of any Calendar Quarter, then Licensee will reimburse Licensor such amount within [***] after such determination plus interest at the rate set forth in Section 3.8 and if the amount underpaid exceeds [***] of the amount

  
 18 

 
actually due, Licensee will also reimburse Licensor for the fees and expenses of the certified public accountant that conducted such accounting. In the event such accounting determines that
Licensee paid Licensor more than the amount properly due in respect of any Calendar Quarter, then any excess payments made by Licensee will be credited against future amounts due to Licensor from Licensee, or if no such future amounts are reasonably
expected to be due to Licensor from Licensee, then Licensor will reimburse Licensee promptly for any overpayment by Licensee. 
 3.9 Late
Payments. Any amount owed by Licensee to Licensor that is not paid within the applicable time period set forth herein will accrue interest at the rate per annum equal to [***]. 

ARTICLE 4 
 TECHNOLOGY
TRANSFER; REGULATORY MATTERS; DILIGENCE; NONCOMPETE 
 4.1 Technology Transfer and Assistance. In accordance with the technology
transfer plan attached as Exhibit B to this Agreement (the “Technology Transfer Plan”), Licensor will provide Licensee with respect to Compounds (a) all results, tabulated data, evaluations and study reports relating
solely and exclusively to Compounds and any product incorporating Compounds, including any preclinical assays, toxicity experiments, methods of synthesis, chemistry, manufacturing and controls, process research/synthesis optimization reports,
analytical methods, bio-analytical methods, formulation research results, and preclinical and tabulated clinical trial data and results relating solely and exclusively Compounds or to such products,
(b) all Exclusively Licensed Know-How that does not fall within the preceding clause (a), (c) all Non-Exclusively Licensed
Know-How and (d) complete and correct copies of all collaborative and other agreements with Third Parties relating to the Licensed Intellectual Property, in each case in accordance with, and to the extent
set forth in, the Technology Transfer Plan. Within [***], Licensor shall transfer to Licensee, in a mutually agreed manner, the quantities of available physical inventory of Compounds as listed in the Technology Transfer Plan. Licensor shall have no
further obligation to make any further physical inventory of Compounds available to Licensee. Licensor will make Commercially Reasonable Efforts to complete all other transfers under the Technology Transfer Plan with respect to Compounds shall occur
within [***] after the Effective Date, and Licensor shall have no further technology transfer obligations after such transfer. Without limiting the foregoing, Licensor shall have no further obligation to disclose or transfer to Licensee any Licensor
Improvements that come into existence after the Effective Date. The materials transferred to Licensee by Licensor under this Section 4.1 are transferred on an “as is” basis, subject only to Licensor’s express representations and
warranties under this Agreement. The Compounds provided to Licensee pursuant to this Article 4 or Exhibit B are research grade and shall not be used in humans. Notwithstanding anything else in this Agreement, Licensor shall have no liability for any
losses, claims, or damages arising from or related to Licensee’s use of such provided Compounds. Licensor will provide reasonable assistance to Licensee for the orderly transfer and transition of all information and materials transferred to
Licensee under the Technology Transfer Plan, including all research and development activities relating to Compounds and any product of Licensor incorporating Compounds in the Field to Licensee for a period not to exceed [***] after the Effective
Date. For clarity, Licensor may, in its sole discretion, provide such assistance thereafter upon the request of Licensee. 
 4.2
Development Plan. Licensee will establish a development plan for each Licensed Product and update it [***] until the First Commercial Sale of the first Licensed Product, after which Licensee shall have no further obligation to provide such
updates. 
 4.3 Product Advisory Committee. Licensee will also establish a product advisory committee (“PAC”)
comprised of qualified individuals who will provide product development guidance to Licensee with respect to the Licensed Products. Licensor may nominate one (1) person to the PAC, who will serve at Licensor’s expense. Prior to First
Commercial Sale of the first Licensed Product, Licensee will provide a written report to Licensor on an annual basis ([***] in each Calendar Year beginning with 2019) regarding 

  
 19 

 
the progress of the development of the Licensed Products, including material updates to the development plan, key milestones and regulatory filings, all of which shall be deemed Licensee
Confidential Information. The PAC will have no decision-making power, but Licensee will consider any recommendations from the PAC in good faith. The PAC shall be dissolved, and the rights and obligations of the Parties under this Section 4.3
shall terminate, effective upon the closing of the first Change of Control of Praxis, as License hereunder. 
 4.4 Regulatory Matters.

 (a) Transfer of IND and Other Regulatory Information. Licensor shall transfer to Licensee the IND for Licensor’s V134444
product. Within [***] after the Effective Date, Licensor will initiate transfer of such IND (as outlined in 21 C.F.R. § 314.72) to Licensee. Licensor agrees to send a letter(s) to the FDA to transfer such IND to Licensee, and Licensee in turn
will notify the FDA that it accepts the transfer. Each Party agrees to provide the other with a copy of their respective letters of transfer. Upon transfer, Licensee will be the IND sponsor and will be responsible for all reporting and other duties
of a sponsor in accordance with applicable law. As soon as reasonably practicable but not later than [***] after the Effective Date, Licensor will transfer to Licensee copies (in electronic or other format) of any regulatory information, safety and
clinical databases of tabulated data and all other regulatory materials prepared or created by Licensor or its Affiliates related solely and exclusively to Compounds or any Licensed Product. 

(b) Regulatory Filings. Licensee (or its Related Parties) will file and own all INDs, marketing authorization applications and
Regulatory Approvals for Licensed Products, and any related items such as investigator’s brochures or IRB approvals, in the Field and in the Territory (collectively, “Regulatory Filings”). Licensee will be solely responsible
for all communications with regulatory authorities related to the Regulatory Filings for any Licensed Product in the Field and in the Territory. 

(c) Cooperation. Licensor will cooperate with, and provide reasonable assistance to Licensee or its Related Parties, in the preparation
and submission of any portions of any Regulatory Filings that rely upon or contain information or data in the Licensed Intellectual Property generated by or on behalf of Licensor. Licensor agrees to make its employees reasonably available to respond
to inquiries from the FDA regarding Know-How that is contained in the V134444 IND and any other filings with the FDA made by or on behalf of Licensor. The obligations of Licensor under this Subsection 4.4(c)
shall apply for [***] after the Effective Date. For clarity, Licensor may, in its sole discretion, provide such cooperation and assistance and make its employees reasonable available thereafter upon the request of Licensee. 

4.5 Diligence. Licensee will use Commercially Reasonable Efforts to research, develop and commercialize at [***] Licensed Product in the
Field in the Territory. For purposes of this Section 4.5, the efforts of Licensee’s Related Parties will also be considered the efforts of Licensee. 

4.6 Noncompete. During the Term, Licensor will not, and will not grant a license to any Third Party under the Licensed Intellectual
Property to, research, develop or commercialize a Licensed Product in any field of use, provided that the foregoing prohibition against the granting of a license shall not apply to the extent of any
pre-existing obligation to grant a license to a Third Party under the Non- Exclusively Licensed Know-How or Lapsed Patents (but
not any other Exclusively Licensed Know-How) as, and to the extent, required under the terms of written license agreement relating to a compound that is not V134444 in effect as of the Effective Date (and
without giving effect to any amendments thereto expanding or modifying the rights of such Third Party to or under the Non-Exclusively Licensed Know-How). 

  
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 4.7 Safety Information. If at any time during the Term, Licensor becomes aware of any
information concerning any safety issues, adverse experiences, or any product complaints associated with adverse experiences, related to any Compound or Licensed Product, Licensor shall, without any further inquiry, promptly provide such information
to Licensee. Licensor agrees to make its employees reasonably available to Licensee for review and response to medical inquiries and complaints to which the Licensed Know-How is, or may reasonably be expected
to be, relevant, for a period of [***] after the Effective Date. For clarity, Licensor may, in its sole discretion, make its employees reasonable available thereafter upon the request of Licensee. 

ARTICLE 5 
 INTELLECTUAL
PROPERTY 
 5.1 Ownership of Inventions. Each Party will own all Know-How developed and
inventions conceived or reduced to practice solely by its employees, agents or independent contractors, including any related Patent. Although the Parties do not intend or expect to jointly develop any
know-how or inventions, in the event they do so, then all inventions made jointly by employees, agents or independent contractors of each Party will be owned jointly by the Parties such that each Party has an
undivided one-half interest in such inventions (“Joint Inventions”). All Patents claiming patentable Joint Inventions will be referred to as “Joint Patents”. Except to the
extent either Party is restricted by the rights granted to the other Party and covenants contained in this Agreement, each Party will be entitled to practice, and to grant to Third Parties or its Related Parties the right to practice, inventions
claimed in a Joint Patent anywhere in the world without restriction or any requirement of gaining the consent of or of accounting to the other Party. Inventorship will be determined in accordance with United States patent laws. 

5.2 Prosecution, Enforcement and Defense of Patents. 

(a) Licensee Patents. As between Licensor and Licensee, Licensee shall have the sole and exclusive right, but not any obligation, at its
expense, to prosecute, maintain and defend with respect to infringement of any Patent Controlled by Licensee that Covers the Licensed Products and is not a Joint Patent. As provided in Section 3.4(d), any amounts awarded or received by Licensee
as lost profits or reasonable royalties (but not any other amounts awarded) as the result of any enforcement action shall be deemed Net Sales of Licensee. 

(b) Joint Patents. Neither Party shall have any obligation to file or prosecute any Joint Patent. To the extent a Party wishes to
prosecute a Joint Patent, the Parties will mutually agree upon which Party will have the first right to prosecute such Joint Patent, based on the contribution of each Party to such invention and each Party’s potential interest in products based
upon such invention. If the Party having such first right does not wish to prosecute such Joint Patent, it shall inform the other Party promptly, but in any event no later than [***] after the Parties have agreed upon which Party had the first right
to prosecute such Joint Patent. If the Party having such first right does not wish to prosecute such Joint Patent, the other Party may, upon written notice to such Party, prosecute such Joint Patent. The Party that prosecutes a Joint Patent pursuant
to this Section 5.2(b) (the “prosecuting Party”) will solely bear its own internal costs for such prosecution and will solely bear the external costs for such prosecution (e.g., outside counsel, filing fees, etc.).
Licensee will have the first right, but not the obligation, to prosecute infringement of any Joint Patents that is related to the Exclusively Licensed Know-How or a product competitive, or potentially
competitive, with a Licensed Product; and Licensor will have the first right, but not the obligation, to prosecute infringement of any Joint Patents in all other cases. The Parties shall first confer and mutually agree regarding any such prosecution
of infringement; provided, however, that Licensee shall have the right, without the consent of Licensor, to assert a Joint Patent against a Third Party in a defense of or counterclaim to any claim or assertion of infringement of a Patent or
misappropriation of Know-How Controlled by such Third Party. 

  
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 (c) Lapsed Patents. Licensor shall not take any action to revive and/or resume
prosecution of the Lapsed Patents without the prior written consent of Licensee. Licensor shall not license, assign or otherwise transfer to any Third Party any of Licensor’s right, title or interest in and to the Lapsed Patents. Licensor shall
not license, assign or otherwise transfer to any Affiliate of Licensor any of Licensor’s right, title or interest in and to the Lapsed Patents unless such Affiliate agrees in writing to all the obligations of Licensor with the respect to the
Lapsed Patents as set forth herein. 
 5.3 Infringement of Third Party Rights. If any Licensed Product that is manufactured, used or
sold by or for Licensee becomes the subject of a Third Party’s claim or assertion of infringement of a Patent or misappropriation of Know-How Controlled by such Third Party, the Party first having notice
of the claim or assertion will promptly notify the other Party in writing, and the Parties will promptly meet to consider the claim or assertion and the appropriate course of action. As between Licensor and Licensee, Licensee shall have the sole and
exclusive right, but not the obligation, to take action to defend any such claim brought by a Third Party. Licensor will reasonably cooperate with Licensee, at Licensee’s sole cost and expense, in its defense of any such Third Party claim.
Nothing in this Section 5.3 will be deemed to relieve either Party of its obligations under Article 7. All costs and expenses of the defense of any such claim shall be borne by Licensee, and as provided in Section 3.4(d), any amounts
recovered by Licensee related to such claim that is for lost sales (including, without limitation, lost profits or reasonable royalties) (but not any other amounts recovered) shall be deemed Net Sales of Licensee. 

5.4 Other Infringement Resolutions. In the event of a dispute or potential dispute that has not ripened into a demand, claim or suit of
the types described in Sections 5.2 and 5.3, the same principles governing control of the resolution of the dispute, consent to settlement of the dispute, and implementation of the settlement of the dispute (including allocating the payment or
receipt of damages, license fees, royalties and other compensation) will apply. 
 5.5 Patent Marking. Each Party agrees to comply
with the patent marking statutes in each country in which a Licensed Product containing a Compound is sold by such Party or its Related Parties. 

ARTICLE 6 

REPRESENTATIONS, WARRANTIES AND COVENANTS 

6.1 Mutual Representations and Warranties. Each Party represents, warrants and covenants to the other Party as follows: 

(a) Corporate Existence and Power. Such Party is a company, corporation, or general partnership duly organized, validly existing and in
good standing under the laws of the jurisdiction in which it is incorporated or organized, and has full corporate or partnership power and authority and the legal right to own and operate its property and assets and to carry on its business as it is
now being conducted and as contemplated in this Agreement, including the right to transfer the rights granted under this Agreement. 
 (b)
Authority and Binding Agreement. As of the Effective Date, (i) it has the corporate or partnership power and authority and the legal right to enter into this Agreement and perform its obligations under this Agreement; (ii) it has
taken all necessary corporate or partnership action on its part required to authorize the execution and delivery of this Agreement and the performance of its obligations under this Agreement, including all board of director approvals,
qualifications, and consents required for share issuance as of the Effective Date; and (iii) this Agreement has been duly executed and delivered on behalf of such Party, and constitutes a legal, valid and binding obligation of such Party that
is enforceable against it in accordance with its terms, subject to bankruptcy, insolvency, reorganization, arrangement, winding-up, moratorium, and similar laws of general application affecting the enforcement
of creditors’ rights generally, and subject to general equitable principles, including the fact that the availability of equitable remedies, such as injunctive relief or specific performance, is in the discretion of the court. 

  
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 (c) No Conflict. It has not entered, and will not enter, into any agreement with any
Third Party that is in conflict with the rights granted to the other Party under this Agreement, and has not taken and will not take any action that would in any way prevent it from granting the rights granted to the other Party under this
Agreement, or that would otherwise materially conflict with or materially adversely affect the rights granted to the other Party under this Agreement. Its performance and execution of this Agreement does not and will not result in a material breach
of any other contract to which it is a party. 
 6.2 Licensor Representations. Licensor represents, warrants and covenants to Licensee
as follows as of the Effective Date: 
 (a) Lapsed Patents; Third Party Agreements. To Licensor’s knowledge, without any
investigation or independent inquiry, the Lapsed Patents constitute all of the Patents and abandoned patent applications or patents owned or Controlled by Licensor that Cover a Compound or any Licensed Product (assuming for this purpose that such
Licensed Product does not contain any other ingredient other than a Compound), or their manufacture or use in the Field, there are no Third Party Agreements of Licensor granting rights in the Lapsed Patents to any Third Party, and none of the
Licensed Intellectual Property is subject to any claim of Control by any Third Party 
 (b) Ownership. Licensor is the sole and
exclusive owner of all right, title and interest in and to the Licensed Intellectual Property, the Licensed Intellectual Property is free and clear of any material liens, charges and encumbrances, except for any purchase money security interest,
liens for taxes, assessments or governmental or other similar charges or levies that are not yet due and payable or that, although due and payable, are being contested in good faith. To Licensor’s knowledge, without any investigation or
independent inquiry, there are no Third Party Agreements pursuant to which Licensor obtained any rights or licenses in or to the Licensed Intellectual Property that would impose any obligations, including obligations relating to the payment of any
milestones, royalties or other fees or charges, with respect to the Compounds or Licensed Products that may be researched, developed or commercialized by Licensee or its Related Parties in accordance with the terms of this Agreement. Licensor has no
knowledge, without any investigation or independent inquiry, of any claim made against it challenging Licensor’s Control of the Licensed Intellectual Property or making any adverse claim of ownership of the Licensed Intellectual Property. 

(c) Additional Agreements. To Licensor’s knowledge, without any investigation or independent inquiry, listed on Exhibit C are all
sponsored research agreements, material transfer agreements, or similar agreements existing as of the Effective Date between Licensor and Third Parties pursuant to which Licensor has granted to any Third Party rights in any Compound, Licensed
Products or Licensed Intellectual Property (other than any Non-Exclusively Licensed Know-How) or obtained from any Third Party any material rights and/or assumed any
material obligations with respect to any Compound, Licensed Products or Licensed Intellectual Property (other than any Non-Exclusively Licensed Know-How) (the
“Additional Agreements”). Prior to the Effective Date Licensor has disclosed and/or provided to Licensee true, complete and correct copies of all such Additional Agreements. 

(d) Non-Infringement of Third Party Rights. To Licensor’s knowledge, without any
investigation or independent inquiry, no claim of infringement of the Patents of any Third Party has been made against Licensor or any of its Affiliates, and Licensor has not received any cease and desist letter or other formal written notice of
infringement, with respect to the development, manufacture, sale or use of Licensed Products. To Licensor’s knowledge, without any investigation or independent inquiry, there are 

  
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no other claims, judgments or settlements against or owed by Licensor or to which Licensor is a party or pending, in each case relating to any Licensed Product. To Licensor’s knowledge,
without any investigation or independent inquiry, neither Licensor nor any of its Affiliates or their respective current or former employees has misappropriated any of the Exclusively Licensed Know-How or Non- Exclusively Licensed Know-How from any Third Party, and Licensor has no knowledge, without any investigation or independent inquiry, of any claim by a Third Party that
such misappropriation has occurred. 
 (e) Licensor Improvements. To Licensor’s knowledge, without any independent inquiry, there
are no Licensor Improvements in existence as of the Effective Date. 
 6.3 Licensee Covenants and Representations. 

(a) Licensee hereby covenants to Licensor that it shall notify Licensor promptly in writing of Licensee’s becoming aware of any
drug-related serious adverse event that arises during the Term in connection with the administration of any Licensed Product. All such notices (and any information related thereto) will be considered Confidential Information of Licensee and will be
maintained in confidence by Licensor. 
 (b) Licensee hereby covenants to Licensor that Licensee shall not sell any equity security senior in
liquidation to the Common Stock prior to the earlier of (i) the closing of a Qualified Financing or (ii)the issuance to Licensor of shares of Series A Preferred Stock as contemplated in Section 3.3(b). Licensee shall notify Licensor
promptly, but in no event fewer than [***] prior to the anticipated closing of a Qualified Financing (other than an IPO), and in no event fewer than [***] prior to the closing of a Qualified Financing that is an IPO. 

(c) Licensee hereby covenants to Licensor that Licensee shall not close any Change of Control prior to the earlier of (i) the closing of a
Qualified Financing or (ii) the issuance to Licensor of shares of Series A Preferred Stock on the same terms as is contemplated in Section 3.3(b). 

(d) Licensee hereby covenants that it shall not use any physical inventory of Compounds received from Licensor hereunder in humans. 

The covenants set forth in Sections 6.3(b) and 6.3(c) shall expire and be of no further force or effect from and after the closing of the first Change of
Control of Praxis, as License hereunder, provided that Licensee has complied with such covenants prior to the fist Change of Control of Praxis. 

(e) Capitalization Representation. Licensee represents and warrants to Licensor that, consistent with the capitalization table of
Licensee attached as Exhibit D, the authorized capital of Licensee as of the Effective Date consists of : (I) [***] shares of Common Stock, [***] shares of which are issued and outstanding, and (II) [***] shares of preferred stock, all of which
shares have been designated Series A Preferred Stock, all of which shares are issued and outstanding. Licensor further represents and warrants to Licensor that all of the issued and outstanding shares of capital stock have been duly authorized, are
fully paid and nonasessable and were issued in compliance with all applicable federal and state securities laws. Licensee has reserved [***] shares of Common Stock for issuance pursuant to equity incentive plans, of which [***] shares are subject to
outstanding options, [***] shares remain available for issuance and [***] shares have been issued subject to restricted stock agreements. 

6.4 Obligations with respect to Third Party Agreements. Licensor shall, upon written request of Licensee, assign to Licensee such of the
Additional Agreements as may be requested by Licensee, subject to the terms and conditions of such Additional Agreements. Licensor is solely liable for any payment obligations (including license fees, milestones or royalties) under any Additional
Agreements prior to such assignment. 

  
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 6.5 No Other Representations. THE EXPRESS REPRESENTATIONS AND WARRANTIES STATED IN
THIS ARTICLE 6 ARE IN LIEU OF ALL OTHER REPRESENTATIONS AND WARRANTIES, EXPRESS, IMPLIED, OR STATUTORY, INCLUDING WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, NON-INFRINGEMENT OR NON-MISAPPROPRIATION OF THIRD PARTY INTELLECTUAL PROPERTY RIGHTS. EACH PARTY DISCLAIMS ANY REPRESENTATION OR WARRANTY THAT THE DEVELOPMENT, MANUFACTURE OR COMMERCIALIZATION OF ANY LICENSED PRODUCT PURSUANT TO THIS
AGREEMENT WILL BE SUCCESSFUL OR THAT ANY PARTICULAR SALES LEVEL WITH RESPECT TO A LICENSED PRODUCT WILL BE ACHIEVED. 
 ARTICLE 7 

INDEMNIFICATION AND INSURANCE 

7.1 Indemnification by Licensee. Licensee will defend, hold harmless, and indemnify (collectively, “Indemnify”)
Licensor and its Affiliates and their respective agents, directors, officers and employees (the “Licensor Indemnitees”) from and against any and all liabilities, expenses, and/or losses, including reasonable legal expenses and
attorneys’ fees (collectively “Losses”) in each case resulting from Third Party suits, claims, actions and demands (each, a “Third Party Claim”) to the extent arising from or related to (a) a breach of any
representation, warranty, covenant or other obligation of Licensee set forth in this Agreement, or (b) the research, development, manufacture or commercialization of Licensed Products by Licensee or its Related Parties, except, in each case, to
the extent such Losses arises from or is related to (A) any act or omission of any Licensor Indemnitee or any Third Party acting on behalf of a Licensor Indemnitee with respect to a Compound, or any product containing a Compound, prior to the
Effective Date, (B) a breach of any representation, warranty, covenant or other obligation of Licensor set forth in this Agreement or (C) the gross negligence or willful misconduct of a Licensor Indemnitee. 

7.2 Procedure. To be eligible to be indemnified under Section 7.1, as applicable, Licensor will provide Licensee with prompt notice
of the claim giving rise to the indemnification obligation pursuant to this Article 7 and the exclusive ability to defend (with the reasonable cooperation of the Licensor) or settle any such claim; provided, however, that Licensee will not enter
into any settlement for damages other than monetary damages without Licensor’s prior written consent, such consent not to be unreasonably withheld, conditioned, or delayed. Licensor has the right to participate, at its own expense and with
counsel of its choice, in the defense of any claim or suit that has been assumed by Licensee. Licensor reserves the right to claim indemnity from Licensee accordance with Section 7.1 upon resolution of the underlying claim, notwithstanding the
provisions of this Section 7.2 requiring Licensor to tender to Licensee the exclusive ability to defend such claim or suit. 
 7.3
Limitation of Liability. NEITHER PARTY WILL BE LIABLE UNDER ANY LEGAL THEORY (WHETHER TORT, CONTRACT OR OTHERWISE) FOR SPECIAL, INCIDENTAL, CONSEQUENTIAL OR PUNITIVE DAMAGES ARISING OUT OF OR RELATED TO THIS AGREEMENT OR THE EXERCISE OF ITS
RIGHTS UNDER THIS AGREEMENT, INCLUDING LOST PROFITS ARISING FROM OR RELATING TO ANY BREACH OF THIS AGREEMENT, REGARDLESS OF ANY NOTICE OF SUCH DAMAGES, EXCEPT AS A RESULT OF A BREACH OF THE CONFIDENTIALITY AND
NON-USE OBLIGATIONS IN ARTICLE 8. NOTHING IN THIS SECTION 7.3 IS INTENDED TO LIMIT OR RESTRICT THE INDEMNIFICATION RIGHTS OR OBLIGATIONS OF EITHER PARTY. 

  
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 7.4 Insurance. Licensee will maintain insurance during the Term of this Agreement and
for a period of at least two (2) years thereafter with a reputable, solvent insurer (carrier rating of AM Best A- VII (or equivalent or better) in at least the following amounts: (a) product
liability insurance with limits of liability not less than [***]; and (b) clinical trial liability insurance with limits of liability not less than [***]. Licensee will provide Licensor with evidence of the existence and maintenance of such
insurance coverage. Notwithstanding the foregoing to the contrary, after the first Change of Control of Praxis, as Licensee hereunder, Licensee shall not be required to maintain such insurance if it maintains a reasonable and customary program of
self-insurance that covers the liabilities and risks described in the foregoing clauses (a) and (b). 
 ARTICLE 8 

CONFIDENTIALITY AND PUBLICITY 

8.1 Confidential Information. Each Party agrees (a) to take all steps reasonably necessary to maintain the confidentiality of the
Confidential Information of the other Party, (b) not to disclose the other Party’s Confidential Information to any Third Party without the prior written consent of such other Party, and (c) to use such Confidential Information only as
necessary to fulfill its obligations or in the reasonable exercise of rights granted to it under this Agreement; provided, however, that the foregoing obligations will not apply to Confidential Information that (i) is in possession of the
receiving Party at the time of disclosure, as reasonably demonstrated by written records and without obligation of confidentiality, (ii) later becomes part of the public domain through no fault of the receiving Party, (iii) is received by
the receiving Party without obligation of confidentiality from a Third Party with a right to such information, or (iv) is developed independently by the receiving Party without use of, reference to, or reliance upon the disclosing Party’s
Confidential Information by individuals who did not have access to such Confidential Information. Furthermore, a Party may disclose Confidential Information of the other Party to (x) its Affiliates, and to its and their directors, employees,
consultants, agents, and insurers, in each case who have a specific need to know such Confidential Information and who are bound by obligations of confidentiality and restriction on use no less stringent than those set forth herein, (y) any
bona fide actual or prospective collaborators, licensees, underwriters, investors, lenders or other financing sources who are obligated to keep such information confidential, to the extent reasonably necessary to enable such actual or prospective
collaborators, licensees, underwriters, investors, lenders or other financing sources to determine their interest in collaborating with, licensing from, underwriting or making an investment in, or otherwise providing financing to, the receiving
Party, and (z) the extent such disclosure is required to comply with applicable law or regulation or the order of a court of competent jurisdiction, to defend or prosecute litigation or to comply with the rules of the U.S. Securities and
Exchange Commission, any stock exchange or listing entity; provided, however, that the receiving Party provides prior written notice of such disclosure to the disclosing Party and takes reasonable and lawful actions to avoid or minimize the degree
of such disclosure. Notwithstanding any other provision of this Agreement, each Party may disclose and use Confidential Information of the other Party as necessary to file or prosecute patent applications, prosecute or defend litigation or otherwise
establish rights or enforce obligations under this Agreement, or to submit Regulatory Filings. Moreover, Licensee may disclose Confidential Information of Licensor relating to the research, development or commercialization of Licensed Products to
entities with whom Licensee has (or may have) a license, collaboration agreement, marketing agreement, development agreement and/or commercialization agreement and who have a need to know such Confidential Information and who are bound by
obligations of confidentiality and restrictions on use no less stringent than those set forth herein. The obligations of this Section 8.1 shall survive for [***] after the Term. 

8.2 Publicity. Each Party understands that this Agreement is likely to be of significant interest to investors, analysts and others and,
therefore, that either Party has the right to make announcements of events or developments with respect to this Agreement that are material to such Party. Each Party agrees that any such announcement will not contain Confidential Information of the
other Party or, if disclosure 

  
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of such Confidential Information is required by law or regulation or the rules of the U.S. Securities and Exchange Commission, any stock exchange or listing entity, will make reasonable efforts
to minimize such disclosure and obtain confidential treatment for any such information that is disclosed to a government agency. Each Party agrees to provide the other Party with a copy of any such public announcement as soon as reasonably
practicable prior to its scheduled release. Except in the case of extraordinary circumstances, each Party will provide the other with an advance copy of any such public announcement at least [***] prior to its scheduled release. Each Party has the
right to expeditiously review and recommend changes to any such public announcement regarding this Agreement, provided that such right of review and recommendation will only apply for the first time that specific information is disclosed and will
not apply to the subsequent disclosure of substantially similar information that has been previously disclosed. 
 8.3 Publications.
Licensee may publish or present the results of research and development of Licensed Product(s), without restriction or any prior review or approval by Licensor, provided that Licensee notifies Licensor of such publication or presentation [***] in
advance of such publication or presentation if such publication or presentation contains any Confidential Information of Licensor. 
 8.4
Prior Confidentiality Agreement. This Article 8 supersedes the prior letter agreement between the Parties regarding the Prior Confidentiality Agreement, with respect to disclosures of or discussions regarding Confidential Information taking
place after the Effective Date. 
 ARTICLE 9 

TERM AND TERMINATION 

9.1 Term. This Agreement will become effective on the Effective Date and unless earlier terminated pursuant to this Article 9, will
remain in effect until the expiration of the last-to-expire Royalty Term for a Licensed Product (the “Term”). Thereafter, the rights granted under
Article 2 will become fully-paid, perpetual and irrevocable. 
 9.2 Elective Termination. 

(a) Licensee has, at any time, the right to terminate this Agreement at will in its entirety upon [***] prior written notice to Licensor, if
such notice is given prior to the Qualified Financing Date, or upon [***] prior written notice to Licensor, if such notice is given on or after the Qualified Financing Date. Notwithstanding the foregoing, any such notice of termination of this
Agreement shall (i) result in Licensor being able to exercise its right to purchase Series A Preferred Stock pursuant to Section 3.3(b) even if the Qualified Financing Date has not occurred, and (ii) not in any way prevent Licensor
from exercising or receiving any of its rights under Sections 3.3(a), 3.3(b), 3.3(c) or 3.3(d) prior to the effective date of any such termination, and Licensor shall carry out the provisions of this Agreement in order to protect the exercise of any
rights of Licensor hereunder. If Licensee is terminating this Agreement pursuant to this Section 9.2(a) on account of a Safety Determination, the applicable notice of termination shall explicitly state that such termination is on account of a
Safety Determination. 
 (b) Licensor has, at any time, the right to terminate this Agreement at will upon [***] notice, provided however,
that in the event of such termination, Licensee’s license rights granted under Article 2 shall survive such termination, and such rights shall become fully-paid, perpetual and irrevocable. 

(c) In the event that a Qualified Financing has not occurred on or before the Qualified Financing Date, Licensor has the right to terminate
this Agreement in its entirety, upon [***] prior written notice to Licensee, at any time prior to the earlier of (i) the expiration of [***] after the Qualified Financing Date and (ii) the exercise by Licensor of its right to purchase
Series A Preferred Stock or Series B Preferred Stock in accordance with Section 3.3(b) or Section 3.3(c); provided, however, that such termination shall not be effective if prior to the effectiveness of such termination, a
Qualified Financing occurs or Licensor’s rights to purchase shares of Series A Preferred Stock and Series B Preferred Stock in accordance with Sections 3.3(b) and 3.3(c) expire. 

  
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 9.3 Termination for Breach. If either Party believes that the other is in material
breach of this Agreement, then the Party holding such belief (the “Non-Breaching Party”) may deliver notice of such breach to the other Party (the “Notified Party”). The
Notified Party will have (a) [***] to cure such breach to the extent involving non-payment of amounts due under Article 3; and (b) [***] to either cure such breach for all other material breaches, or, if cure
of such breach other than non-payment cannot reasonably be effected within such [***] period, to deliver to the Non-Breaching Party a plan reasonably calculated to cure
such breach within a timeframe that is reasonably prompt in light of the circumstances then prevailing, but in any event within a timeframe that is not longer than [***]. Following delivery of such a plan, the Notified Party will carry out the plan
and cure the breach. If the Notified Party fails to cure a material breach of this Agreement as provided above, then the Non-Breaching Party may terminate this Agreement upon written notice to the Notified
Party. If there is a good faith dispute as to the existence or cure of a breach or default pursuant to this Section 9.3, all applicable cure periods will be tolled during the existence of such good faith dispute and no termination for a breach
that is disputed in good faith will become effective until such dispute is resolved. The Parties agree that, if Licensee fails to undertake development activities with respect to a Licensed Product for a period of [***] or longer, then such failure
shall be a material breach permitting Licensor to terminate the Agreement subject to the notice requirement and cure period of this Section 9.3, even if Licensee has not during such time failed to comply with Section 4.4 hereof;
provided, however, that the rights and obligations set forth in this sentence shall terminate and be of no further force or effect immediately upon the closing of the first Change of Control of Praxis, as Licensee hereunder. 

9.4 Termination for Bankruptcy. 

(a) This Agreement may be terminated by Licensor upon the filing or institution of bankruptcy, reorganization, liquidation or receivership
proceedings, or upon an assignment of a substantial portion of the assets for the benefit of creditors by Licensee; provided, however, that in the event of any involuntary bankruptcy or receivership proceeding such right to terminate will only
become effective if Licensee consents to the involuntary bankruptcy or receivership or such proceeding is not dismissed within [***] after the filing of such bankruptcy or receivership. 

(b) All licenses and rights to licenses granted under or pursuant to this Agreement by Licensor to Licensee are, and will otherwise be deemed
to be, for purposes of Section 365(n) of the United States Bankruptcy Code (the “Bankruptcy Code”), licenses of rights to “intellectual property” as defined under Section 101(35A) of the Bankruptcy Code. The
Parties agree that Licensee, as a licensee of such rights under this Agreement, will retain and may fully exercise all of its rights and elections under the Bankruptcy Code. The Parties further agree that that upon commencement of a bankruptcy
proceeding by or against Licensor under the Bankruptcy Code, Licensee will be entitled to a complete duplicate of, or complete access to (as Licensee deems appropriate), all such intellectual property and all embodiments of such intellectual
property. Such intellectual property and all embodiments of such intellectual property will be promptly delivered to Licensee (i) upon any such commencement of a bankruptcy proceeding and upon written request by Licensee, unless Licensor elects
to continue to perform all of its obligations under this Agreement, or (ii) if not delivered under (i) above, upon the rejection of this Agreement by or on behalf of Licensor and upon written request by the Licensee. Licensor (in any
capacity, including debtor-in-possession) and its successors and assigns (including any trustee) agrees not to interfere with the exercise by Licensee or its Affiliates
of its rights and licenses to such intellectual property and such embodiments of intellectual property in accordance with this Agreement, and agrees to assist Licensee and its Affiliates in obtaining such intellectual property and such embodiments
of intellectual property in the possession or control of Third Parties as reasonably necessary or desirable for Licensee to exercise such rights and licenses in accordance with this Agreement. The foregoing provisions are without prejudice to any
rights Licensee may have arising under the Bankruptcy Code or other applicable law. 

  
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 9.5 Consequences of Termination. 

(a) Upon any termination of this Agreement under Sections 9.2, 9.3 or 9.4, all rights and obligations of the Parties shall terminate except as
provided in Sections 9.2(b), 9.5(b) and 9.6. 
 (b) In the event that the license granted to Licensee under this Agreement is terminated, any
granted sublicenses will remain in full force and effect; provided that the Sublicensee is not then in breach of its sublicense agreement and the Sublicensee agrees to be bound to Licensor as a licensor under the terms and conditions of the
sublicense agreement. Licensor will enter into appropriate agreements or amendments to the sublicense agreement to substitute itself for Licensee as the licensor under such agreement, provided that Licensor shall not be obligated to take on any
obligations of Licensee under such agreement that are greater in scope or duration to those obligations set forth in this Agreement. 
 (c)
Upon any termination of this Agreement by Licensee under Section 9.2(a) or by Licensor under Section 9.2(c), 9.3 or 9.4, Licensee shall, at Licensor’s election, promptly transfer to Licensor all Regulatory Filings related to the
Licensed Products, all non-clinical and clinical data related to the Licensed Products and all inventories of Licensed Products (to be provided at Licensee’s cost of such inventories), in each case, and
that is in the possession or Control of Licensee or its Affiliates. The provisions of this Section 9.5(c) shall terminate and be of no further force or effect immediately upon the closing of the first Change of Control of Praxis, as Licensee
hereunder. 
 9.6 Survival. The following provisions will survive any expiration or termination of this Agreement for the period of
time specified in such provision, or if not specified, then they will survive indefinitely: Articles 1, 2 (solely in the case of expiration in accordance with Section 9.1 or termination by Licensor pursuant to Section 9.2(b)), 7, 8, 9, 10
and 11, and Sections 3.5 (solely for so long as required to make a final report of Net Sales of Licensed Products that occur prior to expiration or termination and to make any final payments hereunder as a result thereof), 3.3(d) (solely as to
Licensee’s rights to receive Anti-Dilution Shares upon any issuance and sale of Series B Preferred Stock at or after the Next Financing), 3.6, 3.7, 3.8, 3.9, 5.1, 5.3, and 5.4. Termination of this Agreement will not relieve the Parties of any
liability which accrued under this Agreement prior to the effective date of such termination nor preclude either Party from pursuing all rights and remedies it may have under this Agreement or at law or in equity with respect to any breach of this
Agreement. The remedies provided in this Article 9 are not exclusive of any other remedies a Party may have in law or equity. 
 ARTICLE
10 
 DISPUTE RESOLUTION 

10.1 Dispute Resolution. If the Parties are unable to resolve any dispute arising out of or in connection with this Agreement (each a
“Dispute”), either Party may, by written notice to the other, have such Dispute referred to senior executive officers designated by each Party, or their respective designees for attempted resolution by good faith negotiations within
[***] after such notice is received. In such event, the Parties shall cause their respective officers or their designees to meet (face-to-face or by teleconference) and
be available to attempt to resolve such issue. If the Parties should resolve such Dispute, a memorandum setting forth their agreement shall be prepared and signed by both Parties at either Party’s request. If the Parties are unable to resolve
any Dispute, either Party may submit the matter for resolution pursuant to Section 10.2. 

  
 29 

 10.2 Arbitration. 

(a) If any Dispute has not been resolved pursuant to the provisions of Section 10.1, then the Parties shall settle the Dispute by binding
arbitration administered by JAMS, Inc., the alternative dispute resolution company formerly known as Judicial Arbitration and Mediation Services, Inc., pursuant to its Comprehensive Arbitration Rules and Procedures then in effect (the “JAMS
Rules”), and judgment on the arbitration award may be entered in any court having jurisdiction thereof; provided, however, and notwithstanding anything to the contrary, that any Dispute concerning ownership or assignment of
intellectual property rights, or the infringement, validity or enforceability of any Patent Right shall be heard exclusively by a federal court of competent jurisdiction in accordance with Section 11.2 and no finding, opinion or judgment by any
arbitrator with respect to such matters shall be enforceable or have any legal effect as between the Parties. 
 (b) The arbitration shall be
conducted by a panel of three (3) arbitrators experienced in the business of biopharmaceuticals. If the issues in dispute involve scientific, technical or commercial matters, then any arbitrator chosen under this Agreement shall have
educational training and industry experience sufficient to demonstrate a reasonable level of relevant scientific, technical and commercial knowledge as applied to the biopharmaceutical industry. If the issues in dispute involve patent matters, but
subject to the proviso in Section 10.2(a), then at least two (2) of the arbitrators shall be licensed patent attorneys. Within thirty (30) days after a Party demands arbitration, each Party shall select one person to act as
arbitrator, and the two Party-selected arbitrators shall select a third arbitrator within thirty (30) days after their own appointment. If the arbitrators selected by the Parties are unable or fail to agree upon the third arbitrator, then the
third arbitrator shall be appointed in accordance with the JAMS Rules. The location of arbitration shall be New York, New York. All proceedings and communications as part of the arbitration shall be in English. Following selection of the third
arbitrator, the arbitrators shall complete the arbitration proceedings and render an award pursuant to a written decision within six (6) months after the last arbitrator is appointed. 

(c) Each Party shall bear its own costs and expenses and attorneys’ fees and an equal share of the arbitrators’ fees and any
administrative fees for arbitration, unless in each case the arbitrators agree otherwise, which they are hereby empowered, authorized and instructed to do if they determine that to be fair and appropriate. 

(d) The decision of the arbitrators shall be the sole, exclusive and binding remedy between the Parties regarding the determination of all
Disputes presented. The arbitrators shall have the authority to grant specific performance. Judgment upon the award so rendered may be entered in a court having jurisdiction or application may be made to such court for judicial acceptance of any
award and an order of enforcement, as the case may be. Any monetary payment to be made by a Party pursuant to a decision of the arbitrators shall be made in US Dollars, free of any tax or other deduction. Notwithstanding anything to the contrary in
this Agreement, each Party shall have the right at any time to seek injunctive or other forms of equitable relief from any court of competent jurisdiction. 

ARTICLE 11 

MISCELLANEOUS 
 11.1
Entire Agreement; Amendment. This Agreement, including the Exhibits attached to and incorporated into this Agreement, sets forth the complete, final and exclusive agreement and all the covenants, promises, agreements, warranties,
representations, conditions and understandings between the Parties with respect to the subject matter of this Agreement and supersedes and terminates all prior agreements and understandings between the Parties with respect to such subject matter,
other than the Prior Confidentiality Agreement which shall continue in full force and effect with respect to disclosures of the Parties prior to the Effective Date. No subsequent alteration, amendment, change or addition to this Agreement will be
binding upon the Parties unless reduced to writing and signed by an authorized officer of each Party. 

  
 30 

 11.2 Governing Law. This Agreement will be construed in accordance with, and governed
in all respects by, the laws of the state of Delaware (without giving effect to principles of conflicts of laws that would require the application of any other law); provided that matters of intellectual property law will be determined in accordance
with the United States federal law. The Parties hereby submit to the jurisdiction of the state and federal courts located in New Castle County, Delaware, and waive any defense of inconvenient forum to the maintenance of any action or proceeding in
such courts. 
 11.3 Specific Performance. Subject to Article 10 and Section 11.2, in addition to any and all other remedies that
may be available at law in the event of breach of this Agreement, the non-breaching Party shall be entitled to specific performance of the agreements and obligations of the breaching Party hereunder and to
such injunctive or other equitable relief as may be granted by a court of competent jurisdiction. 
 11.4 Force Majeure. Each Party
will be excused from the performance of its obligations under this Agreement to the extent that such performance is prevented by a force majeure event and the nonperforming Party promptly provides notice of the prevention to the other Party.
Such excuse will be continued so long as the condition constituting force majeure continues and the nonperforming Party uses reasonable efforts to remove the condition. For purposes of this Agreement, force majeure will include
conditions beyond the reasonable control of the Parties, including an act of God or terrorism, voluntary or involuntary compliance with any regulation, law or order of any government, war, civil commotion, labor strike or lock-out, epidemic, failure or default of public utilities or common carriers, destruction of production facilities or materials by fire, earthquake, storm or like catastrophe. 

11.5 Notices. Any notice required or permitted to be given under this Agreement will be in writing, will specifically refer to this
Agreement and will be deemed to have been sufficiently given for all purposes upon receipt if delivered (a) by first class certified or registered mail, postage prepaid, (b) international express delivery service or (c) personally.
Unless otherwise specified in writing, the notice addresses of the Parties will be as described below. 
  

					
		 	For Licensee:	  	Praxis Precision Medicines, Inc.
		 		  	101 Main Street, Suite 1210
		 		  	Cambridge, MA 02142
		 		  	Attention: Chief Executive Officer
			
		 	With a copy to:	  	Goodwin Procter LLP
		 		  	100 Northern Avenue
		 		  	Boston, MA 02210
		 		  	Attn: Richard Hoffman
			
		 	For Licensor:	  	Purdue Neuroscience Company
		 		  	One Stamford Forum
		 		  	201 Tresser Boulevard
		 		  	Stamford, Connecticut 06901-3431
		 		  	Attention: Paul Medeiros and Don Kyle

  
 31 

					
		 	With copies to:	  	Purdue Pharma L.P.
		 		  	One Stamford Forum
		 		  	201 Tresser Boulevard
		 		  	Stamford, Connecticut 06901-3431
		 		  	Attention: General Counsel
			
		 		  	Norton Rose Fulbright US LLP
		 		  	1301 Avenue of the Americas
		 		  	New York, New York 10019-6022
		 		  	Attention: Stuart D. Baker

 11.6 No Strict Construction. This Agreement has been prepared jointly and will not be strictly
construed against either Party. 
 11.7 Assignment. Neither Party may assign or transfer this Agreement or any rights or obligations
under this Agreement without the prior written consent of the other Party, except that, subject to Section 11.8, a Party may make such an assignment or transfer without the other Party’s consent (a) to the assigning Party’s
Affiliates or (b) to the successor to all or substantially all of the business or assets of such Party to which this Agreement relates (whether by merger, sale of stock, sale of assets or other transaction). Any permitted successor or assignee
of rights and/or obligations under this Agreement will, in a writing to the other Party, expressly assume performance of such rights and/or obligations. Any permitted assignment will be binding on the successors of the assigning Party. Any
assignment or attempted assignment by either Party in violation of the terms of this Section 11.7 will be null and void. 
 11.8
Performance by Affiliates. Each of Licensor and Licensee acknowledge that their obligations under this Agreement may be performed by their respective Affiliates. Notwithstanding any delegation of obligations under this Agreement by a Party to an
Affiliate, each Party will remain primarily liable and responsible for the performance of all of its obligations under this Agreement and for causing its Affiliates to act in a manner consistent with this Agreement. Wherever in this Agreement the
Parties delegate responsibility to Affiliates or local operating entities, the Parties agree that such entities will not make decisions inconsistent with this Agreement, amend the terms of this Agreement or act in breach of its terms. 

11.9 Independent Contractors. It is understood and agreed that the relationship between the Parties is that of independent contractors
and that nothing in this Agreement will be construed as creating a partnership for tax purposes or as an authorization for either Party to act as the agent for the other Party. 

11.10 Further Actions. Each Party agrees to execute, acknowledge and deliver such further instruments, and to do all such other acts, as
may be necessary or appropriate in order to carry out the purposes and intent of this Agreement. 
 11.11 Severability. Each provision
in this Agreement is independent and severable from the others, and no provision will be rendered unenforceable because any other provision may be invalid or unenforceable in whole or in part. If the scope of any restrictive provision in this
Agreement is too broad to permit enforcement to its full extent, then such restriction will be reformed to the maximum extent permitted by law. 

11.12 Headings. The headings for each Article and Section in this Agreement have been inserted for convenience of reference only and are
not intended to limit or expand on the meaning of the language contained in the particular Article or Section. 

  
 32 

 11.13 No Waiver. Any delay in enforcing a Party’s rights under this Agreement,
or any waiver as to a particular default or other matter, will not constitute a waiver of such Party’s rights to the future enforcement of its rights under this Agreement, except with respect to an express written and signed waiver relating to
a particular matter for a particular period of time. 
 11.14 Interpretation. Except where the context otherwise requires, wherever
used, the singular includes the plural, the plural the singular, the use of any gender applies to all genders. The word “or” has the inclusive meaning that is typically associated with the phrase “and/or”; the word
“and” is used in the conjunctive sense. The term “including,” “include,” or “includes” means including, without limiting the generality of any description preceding such term. Unless the context requires
otherwise, (i) any definition of or reference to any agreement, instrument or other document will be construed as referring to such agreement, instrument or other document as from time to time amended, supplemented or otherwise modified
(subject to any restrictions on such amendments, supplements or modifications set forth herein or therein), (ii) any reference to any applicable laws will be construed as referring to such laws as from time to time enacted, repealed or amended,
(iii) any reference to any person will be construed to include the person’s successors and permitted assigns, (iv) the words “herein”, “hereof” and “hereunder”, and words of similar import, will be
construed to refer to this Agreement in its entirety and not to any particular provision hereof, (v) any reference to the words “mutually agree” or “mutual written agreement” will not impose any obligation on either Party to
agree to any terms relating thereto or to engage in discussions relating to such terms except as such Party may determine in such Party’s sole discretion, (vi) all references to Sections, Exhibits or Schedules will be construed to refer to
Sections, Exhibits and Schedules to this Agreement, (vii) the word “days” means calendar days unless otherwise specified, and (viii) the words “copy” and “copies” and words of similar import when used in this
Agreement include, to the extent available, electronic copies, files or databases containing the information, files, items, documents or materials to which such words apply. 

11.15 No Strict Construction. Each Party represents that it has been represented by legal counsel in connection with this Agreement and
acknowledges that it has participated in the drafting hereof. In interpreting and applying the terms and provisions of this Agreement, the Parties agree that no presumption will apply against the Party which drafted such terms and provisions. 

11.16 Counterparts. This Agreement may be executed in two (2) or more counterparts, each of which will be deemed an original, but
all of which together will constitute one (1) and the same instrument. For purposes of executing this Agreement, a facsimile copy of this Agreement, or .pdf copy, including the signature pages, will be deemed an original. 

[Signature page follows] 

  
 33 

 In Witness Whereof the Parties have executed this Agreement in duplicate originals by their duly
authorized officers as of the Effective Date. 
  

									
	Praxis precision medicines, inc.	 		  	PURDUE NEUROSCIENCE COMPANY by its general partner, Purdue Pharma L.P. by its general partner, Purdue Pharma Inc.
					
	By:	 	 /s/ Kiran Reddy
	 	        	  	By:	  	 /s/ Edward B. Mahony

	Name: Kiran Reddy	 		  	Name: Edward B. Mahony
	Title: President & CEO	 		  	Title: EVP
	Date: 12/31/17	 		  	Date: 12/31/17

 Exhibit A 

[***] 

  
 35 

 Exhibit B 

[***] 

  
 36 

 Exhibit C 

[***] 

  
 37 

 Exhibit D 

[***] 

  
 38 

 Schedule 1.80 

[***] 

 Schedule 1.81 

[***]

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