Document:

EX-10.16

 Exhibit 10.16 

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). 

  
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 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. 

  
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 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. 

  
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 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). 

  
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 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-

  
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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. 

  
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 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 [***]
	  	[***]

  
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 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 [***] 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). 

  
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 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

  
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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 

  
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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 

  
 23 

 
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. 

  
 28 

 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 

[***]EX-10.17

 Exhibit 10.17 

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. 

COOPERATION AND LICENSE AGREEMENT 

BETWEEN 

ROGCON INC. 

AND 

PRAXIS PRECISION MEDICINES, INC. 

 COOPERATION AND LICENSE AGREEMENT 

This COOPERATION AND LICENSE AGREEMENT (the “Agreement”) is made and entered into as of the 11th day of September, 2019
(the “Effective Date”) by and between RogCon Inc., a Delaware corporation, having its principal place of business at 5251 LaGorce Drive, Miami Beach, FL 33140 RogCon”), and Praxis
Precision Medicines, Inc., a Delaware corporation with its principal place of business at 101 Main Street #1210, Cambridge, MA 02142 (“Praxis”). Praxis and RogCon each may be referred to herein individually as a
“Party” or collectively as the “Parties.” 
 RECITALS 

WHEREAS, coincident with the execution of this Agreement, Praxis is entering into that certain Research Collaboration, Option and
License Agreement with Ionis Pharmaceuticals, Inc. (“Ionis”) (the “Ionis Agreement”) pursuant to which Praxis and Ionis will, among
other things, collaborate to develop an antisense oligonucleotide product for the treatment of epilepsy caused by mutations of the SCN2A gene and Praxis will have the exclusive right to commercialize such product, all on the terms and conditions set
forth therein; 
 WHEREAS, RogCon initially identified the opportunity with Ionis and possesses certain Patent Rights,
Know-How, technology and expertise with respect to such a product; and 
 WHEREAS, RogCon and Praxis are interested in
combining their expertise to cooperate with respect to the development and commercialization of such product, all on the terms and conditions set forth below. 

NOW, THEREFORE, in consideration of the respective covenants, representations, warranties and agreements set forth herein, the Parties
hereto agree as follows: 
 ARTICLE 1. 

DEFINITIONS 
 The terms
used in this Agreement with initial letters capitalized, whether used in the singular or the plural, will have the meaning set forth (a) in the Ionis Agreement (except that references to a Party or the Parties, shall mean the Party or Parties
hereto), (b) if not listed in the Ionis Agreement, in APPENDIX 1, or (c) if not listed in the Ionis Agreement or the in APPENDIX 1, in places throughout this Agreement. 

ARTICLE 2. 
 ACTIVITIES /
COORDINATION 
  

	2.1	 Coordination Committee. 

 

	 	2.1.1.	 Scope/Decision-Making. The Parties shall establish a “Coordination Committee” to
(a) consider strategic matters pertaining to the Research, Development, and Commercialization of Product for the Field in the Major Markets (including associated regulatory matters) and (b) review and monitor the progress of such
activities. The Coordination Committee shall be composed of three (3) individuals 

  
 2 

	 	
appointed by each Party, which shall include the Chief Executive Officers from each Party. All decisions of the Coordination Committee shall be made by consensus with each Party acting in good
faith; however, if the Coordination Committee is unable to make any decision after good faith discussions, then the Chief Executive of Praxis shall have the right to make such decision. All such decisions shall be in writing. For clarity, the
Coordination Committee’s decision-making (and the Praxis Chief Executive’s final decision-making) shall not include any right (a) to unilaterally impose any obligation on the other Party (b) to amend, modify or waive compliance
with this Agreement, (b) to determine whether or not a Party has met its obligations under the Agreement, or (c) to determine whether or not a breach of this Agreement has occurred, and no decision of the Coordination Committee shall be in
contravention of any terms and conditions of this Agreement. 

  

	 	2.1.2.	 Meetings. The Coordination Committee will meet prior to each meeting of the JSC under the Ionis
Agreement to discuss matters on the agenda for the JSC meeting in an attempt to obtain alignment. After the dissolution of the JSC under the Ionis Agreement, the Coordination Committee will meet twice annually until the expiration of the Commitment
Period. Additionally, each Party may also call for special meetings twice per year at any time during the Term to address matters requiring prompt attention with at least [***] prior notice (or such shorter period as necessary to address exigent
matters) to resolve particular matters identified by such Party in such notice. 

  

	2.2	 Certain Activities. 

 

	 	2.2.1.	 By Praxis. Praxis will conduct (itself or through one or more designees), at its own cost and
expense, the Research and other activities assigned to it under the Research Plan, Development Candidate Identification Plan (including recordkeeping and reporting) or otherwise under the Ionis Agreement. 

 

	 	2.2.2.	 By RogCon. Subject to Section 4.1.3, RogCon will conduct (itself or through one or more
third party service providers approved in advance by Praxis), the Research and other activities related to the Development of a Product as may be reasonably requested by Praxis from time to time (such activities, “RogCon
Activities”). In addition, upon Praxis’ request, RogCon shall assign or otherwise transfer the benefits of its agreements with certain third party service providers to Praxis, including execution of such documents or taking
such other actions reasonably requested by Praxis as may be necessary to effect such assignment or transfer. 

  

	2.3	 Selection of Development Candidate. As between the Parties, Praxis shall have the right to select
the Development Candidate and any Related Compound(s) and make other decisions allocated to Praxis under the Ionis Agreement; provided that Praxis shall consult with RogCon (through the Coordination Committee) and take into consideration
RogCon’s positions with respect thereto. 

  
 3 

	2.4	 Provision of Information. Praxis will promptly provide to RogCon (through the Coordination
Committee) all information (a) received from Ionis under the Ionis Agreement (including the Development Candidate Data Package) or (b) generated by or on behalf of Praxis or its Affiliates in the course of performing its activities under
the Ionis Agreement, in each case of (a) and (b), only if and to the extent such information is reasonably necessary for the Coordination Committee to conduct those matters for which is it responsible. 

 

	2.5	 Invitations. Praxis will use good faith efforts to invite RogCon to each scheduled meeting
between Praxis and Ionis under the Ionis Agreement (and forward any meeting invite received from Ionis on which a RogCon representative is not copied) at which strategic matters pertaining to the Research, Development or Commercialization of Product
for the Field in the Major Markets (including associated regulatory matters) are being discussed or decided, reasonably in advance to facilitate RogCon’s participation. For clarity, RogCon will have (i) the right to have a single
representative attend, and to the extent permitted by the Ionis Agreement, participate in any such meeting and (ii) no right to have any of its representatives attend any portion of a meeting not pertaining to Product. 

ARTICLE 3. 
 LICENSES /
EXCLUSIVITY 
  

	3.1	 License to Praxis. Subject to the terms and conditions of this Agreement and the
Non-Exclusive Patent License Agreement dated September 11, 2019 between RogCon and Ionis (the RogCon- Ionis Agreement”), RogCon hereby grants, on behalf of itself and its Affiliates, to Praxis an
exclusive, worldwide license under the RogCon IP to Research, Develop and Commercialize Product in the Field. Praxis shall have the right to exercise such license through its Affiliates solely for as long as such entity remains an Affiliate of
Praxis, and Praxis shall remain responsible for the compliance of such Affiliate with the applicable terms of this Agreement. 

  

	3.2	 Sublicenses. The license under Section 3.1 includes the right to grant sublicenses
(through one or more tiers) within the scope thereof, including entering into any marketing partnering arrangement or any option for any such sublicense or arrangement (each, a “Sublicense”), without the consent of
RogCon, subject to the following: 

  

	 	3.2.1.	 Process. Praxis agrees to keep RogCon reasonably informed of any discussion with respect to a
proposed Sublicense; and at RogCon’s reasonable request in connection therewith, Praxis will discuss any concerns that RogCon has with respect thereto. 

  

	 	3.2.2.	 Copies. Praxis shall promptly notify RogCon of the grant of each Sublicense and provide RogCon a
copy of the final executed sublicense agreement, redacted for information not pertinent to this Agreement. 

  

	 	3.2.3.	 Responsibility. Praxis shall be responsible for the failure of any other Person bound by a
Sublicense, and will use all commercially reasonable efforts to ensure that any such other Person complies in all material respect with any such Sublicense and with all relevant restrictions, limitations and obligations in this Agreement.

  
 4 

	3.3	 No Other Rights. Each Party acknowledges that the rights and licenses granted under this
ARTICLE 3 and elsewhere in this Agreement are limited to the scope expressly granted. Accordingly, except for the rights expressly granted under this Agreement, no right, title, or interest of any nature whatsoever is granted whether by
implication, estoppel, reliance, or otherwise, by either Party to the other Party. All rights with respect to Know-How, Patent Rights or other intellectual property rights that are not specifically granted herein are reserved to the owner
thereof. 

  

	3.4	 Exclusivity of Efforts. During the Term of this Agreement, RogCon agrees on its behalf and on
behalf of its controlled Affiliates (a) not to conduct, participate in or sponsor, directly or indirectly, any activities directed toward the research of an ASO that is designed to bind to the mRNA or pre-mRNA and down-regulate the expression
of SCN2A gene products (each, a “Competing Compound”) or the development, commercialization or exploitation of any pharmaceutical product incorporating any Competing Compound (collectively, such activities
“Competing Activities”) or (b) appoint, license or otherwise authorize any Third Party, whether pursuant to such license, appointment, or authorization or otherwise to perform any Competing Activities. For clarity,
nothing in this Section 3.4 is intended to prevent RogCon from conducting, participating in, or sponsoring (i) any independent research, development or commercialization of non-ASO compounds or pharmaceutical products incorporating
the same, whether itself or through others, (ii) general technology development, including the discovery, research and development of assays or informatics, technologies, in each case with general applicability, or (iii) to generate
specificity data, including negative controls and information with respect thereto, in each case of (i)—(iii) not directed predominantly to Competing Activities. 

ARTICLE 4. 
 FINANCIAL
TERMS 
  

	4.1	 Consideration. In consideration for the obligations of RogCon and the rights and licenses granted
to Praxis hereunder, the Parties agree as follows: 

  

	 	4.1.1.	 Re-characterization of outstanding loan. The Parties acknowledge that all amounts outstanding as
of the Effective Date under that certain Loan Agreement, that certain Promissory Note and that certain Security Agreement, each dated December 21, 2018 (collectively, the “Credit Facility”) between Praxis
and RogCon shall be capitalized and no longer due and the Credit Facility is hereby terminated in its entirety by mutual agreement and neither Party shall have any further liability thereunder. 

 

	 	4.1.2.	 Repayment of certain notes. Within [***] following the Effective Date, Praxis shall retire the
total amounts of principal and interest outstanding as of the Effective Date under those certain Non-Negotiable Demand Promissory Notes, dated December 19, 2018, between RogCon Inc. and London Management Corp. and PN Family Enterprises, Ltd.

  
 5 

	 	4.1.3.	 Reimbursement. Within [***] after the Effective Date, RogCon shall prepare and provide to Praxis
(a) a written report which details the Research and Development activities performed in relation to Product prior to the Effective Date, and an accounting of all out-of-pocket costs incurred by RogCon in connection therewith, along with
reasonable supporting documentation with respect thereto and (b) an invoice for the amount of the out-of-pocket costs specified in such report. In addition, within [***] after the end of every calendar month during the Term during which RogCon
performs RogCon Activities, RogCon shall prepare and provide to Praxis (i) a written report which details the activities performed and an accounting of all out-of-pocket costs incurred by RogCon in performing such activities in the prior
calendar month, along with reasonable supporting documentation with respect thereto and (ii) an invoice for the amount of the out-of-pocket costs specified in such report. All undisputed costs within the aforementioned invoices shall be paid by
Praxis in accordance with Section 4.2.2. Praxis will have the right to have an independent certified public accounting firm of internationally recognized standing, reasonably acceptable to RogCon, have access during normal business
hours, and upon reasonable prior written notice, to RogCon’s records as may be reasonably necessary to verify the accuracy of out-of-pocket costs reimbursable or reimbursed by Praxis pursuant to this Section 4.1.3 for any calendar month,
Calendar Quarter or Calendar Year within the preceding [***]; provided, however, that Praxis will not have the right to conduct more than [***] such audit in any Calendar Year. The accounting firm will disclose to Praxis
only whether the invoiced out-of-pocket expenses reimbursed or reimbursable pursuant to this Section 4.1.3 are correct and the details of any discrepancies. Praxis will bear the cost of such audit unless the audit reveals an
underreporting of more than the greater of [***] of amounts paid or payable to RogCon over an applicable Calendar Year, in which case RogCon will promptly reimburse the cost of the audit. If, based on the results of such audit, amounts were overpaid
by Praxis to RogCon, RogCon will issue to Praxis a credit in the amount of such overpayment, which credit may be applied against future royalty payments owed by Praxis to RogCon under this Agreement. Praxis and its accounting firm will treat the
financial information subject to review under this Section 4.1.3 in accordance with the confidentiality provisions of ARTICLE 10. 

 

	 	4.1.4.	 Milestone Payment. In partial consideration for the rights and licenses granted to Praxis
hereunder, Praxis will pay to RogCon a one-time, non-refundable, non-creditable milestone payment of $3 million, which milestone will be payable within [***] after the date both of the following conditions have been met: (a) the first Profit
Share Payment has become due and payable to RogCon under Section 4.1.5 and (b) the Additional Milestone Payment, the [***] and the [***] (each as defined in the Ionis Agreement) have become due and payable to Ionis under the Ionis
Agreement. 

  

	 	4.1.5.	 Profit Share Payments. In partial consideration for the rights and licenses granted
to Praxis hereunder, Praxis will pay to RogCon the percentages of Net Profits as set forth in TABLE 1 below (collectively, the “Profit Share Payments”)-. 

  
 6 

			
	 TABLE
1

	 Timing
	  	Percentage of
Net Profits
	For all Net Profits generated during the period beginning on the Effective Date and ending on March 31 of the Calendar Year following the first Calendar Year in which annual, worldwide Net Product Revenues first exceed
[***]	  	[***]
		
	For all Net Profits generated during the period beginning on April 1 of the Calendar Year following the first Calendar Year in which annual, worldwide Net Product Revenues first exceed [***] and until March 31 of the
Calendar Year following the first Calendar Year in which annual, worldwide Net Product Revenues first exceed [***]	  	[***]
		
	For all Net Profits generated during the period beginning on April 1 of the Calendar Year following the first Calendar Year in which annual, worldwide Net Product Revenues first [***]	  	[***]

 For the avoidance of doubt, even if annual, worldwide Net Product Revenues never exceed [***], Praxis will
still pay to RogCon [***] of all Net Profits generated after the Effective Date. 
  

	4.2	 Payment Logistics / Records. 

 

	 	4.2.1.	 Payment Reports. Each payment of a Profit Share Payment will be accompanied by a report
summarizing the calculation of Net Profits (including the calculation of (a) Net Product Revenues, (b) Net Sublicense Revenues, and (c) Net Recoveries) during the relevant Calendar Quarter. If no Profit Share Payment is payable in
respect of a given Calendar Quarter, Praxis will submit a written report to RogCon so indicating. 

  

	 	4.2.2.	 Mode of Payment. All payments under this Agreement will be, unless expressly provided herein
otherwise, (a) payable in full in U.S. dollars (b) made by wire transfer of immediately available funds to an account designated by RogCon in writing, and (c) made within [***] of invoice. Whenever for the purposes of calculating any
Profit Share Payment payable under this Agreement conversion from any foreign currency will be required, all amounts will first be calculated in the currency of sale and then converted into U.S. dollars by using the rate used by Praxis to report its
audited finances or, if not so reported, by applying the monthly average rate of exchange calculated by using the foreign exchange rates published in Bloomberg during the applicable month starting two Business Days before the beginning of such month
and ending two Business Days before the end of such month. 

  

	 	4.2.3.	 Records Retention. Commencing with the first accrual of Net Profits, Praxis will keep, and will
require its Affiliates to keep (all in accordance with GAAP, consistently applied), complete and accurate records pertaining to Net Profits for a period of [***] after the year in which such Net Profits accrue and in sufficient detail to permit
RogCon to confirm the accuracy of any Profit Share Payment hereunder. 

  
 7 

	 	4.2.4.	 Audits of Payment Reports. RogCon will have the right to have an independent certified public
accounting firm of internationally recognized standing, reasonably acceptable to Praxis, have access during normal business hours, and upon reasonable prior written notice, to Praxis’ records as may be reasonably necessary to verify the
accuracy of Net Profits and any other payment due pursuant to this ARTICLE 4, as applicable, for any Calendar Quarter or Calendar Year within the preceding [***]; provided, however, that RogCon will not have the right to conduct more
than [***] such audit in any Calendar Year. The accounting firm will disclose to RogCon only whether the reported Net Profits and any other payments due pursuant to this ARTICLE 4 are correct and details of any discrepancies. RogCon will bear
the cost of such audit unless the audit reveals an underreporting of more than the greater of [***] of amounts payable to RogCon over an applicable Calendar Year, in which case Praxis will promptly reimburse the cost of the audit. If, based on the
results of such audit, additional payments are owed by Praxis under this Agreement, Praxis will make such additional payments, with interest as set forth in Section 4.2.5(d), within [***] after the date on which such accounting
firm’s written report is delivered to Praxis. If, based on the results of such audit, amounts were overpaid by Praxis to RogCon, RogCon will issue to Praxis a credit in the amount of such overpayment, which credit may be applied against future
royalty payments owed by Praxis to RogCon under this Agreement. RogCon and its accounting firm will treat the financial information subject to review under this Section 4.2.4 in accordance with the confidentiality provisions of
ARTICLE 10. 

  

	 	4.2.5.	 Taxes. 

 

	 	(a)	 Each Party will be solely responsible for the payment of all taxes imposed on its share of income arising
directly or indirectly from the activities of the Parties under this Agreement. 

  

	 	(b)	 The Parties agree to cooperate with one another and use reasonable efforts to lawfully avoid or reduce tax
withholding or similar obligations in respect of royalties, milestone payments, and other payments made by Praxis to RogCon under this Agreement. To the extent Praxis is required to deduct and withhold taxes, interest or penalties on any payment,
Praxis will pay the amounts thereof to the proper governmental authority for the account of RogCon and remit the net amount (i.e., the payment net of such taxes, interest and/or penalties) to RogCon in a timely manner. Praxis will promptly furnish
RogCon with proof of payment of such taxes. If documentation is necessary to secure an exemption from, or a reduction in, any withholding taxes, the Parties will provide such documentation to the extent they are entitled to do so.

  
 8 

	 	(c)	 RogCon will provide Praxis with any and all tax forms that may be reasonably necessary in order for Praxis to
lawfully not withhold tax or to withhold tax at a reduced rate under an applicable bilateral income tax treaty. Following Praxis’s timely receipt of such tax forms from RogCon, Praxis will not withhold tax or will withhold tax at a reduced rate
under an applicable bilateral income tax treaty, if appropriate under the applicable laws. RogCon will provide any such tax forms to Praxis upon request and in advance of the due date. Each Party will provide the other with reasonable assistance to
determine if any taxes are applicable to payments under this Agreement and to enable the recovery, as permitted by Applicable Law, of withholding taxes resulting from payments made under this Agreement, such recovery to be for the benefit of the
Party who would have been entitled to receive the money but for the application of withholding tax under this Section 4.2.5. 

  

	 	(d)	 The provisions of this Section 4.2.5 are to be read in conjunction with the provisions of
Section 12.1 below. 

  

	 	4.2.6.	 Interest. If Praxis fails to make any undisputed payment due to RogCon under this Agreement, by
the deadline specified in this ARTICLE 4, interest will accrue daily at an annual rate equal to [***]. 

  

	 	4.2.7.	 Delivery of Financial Statements. RogCon shall deliver to Praxis (a) as soon as practicable,
but in any event within fifteen (15) days after the end of each of the first three (3) quarters of each fiscal year of RogCon, 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, and (b) as soon as practicable, but in any event within thirty (30) days after the end of each fiscal year of RogCon, an unaudited statement of income and cash
flows for such fiscal year and an unaudited balance sheet and statement of stockholders’ equity as of the end of such fiscal year. All of the financial statements provided pursuant to clauses (a) and (b) above will be 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. In addition, RogCon shall deliver to
Praxis as soon as practicable, but in any event within ninety (90) days after the Effective Date, audited statements of RogCon’s income and cash flows and an audited balance sheet and statement of stockholders’ equity for fiscal year
2018. Without limiting the foregoing, RogCon will provide Praxis with such reasonable assistance and support as may be requested by Praxis with respect to any questions Praxis has in regards to the financial statements provided to it by RogCon
pursuant to this Section 4.2.7. 

  
 9 

 ARTICLE 5. 

INTELLECTUAL PROPERTY 
  

	5.1	 Agreement IP. Praxis will own all discoveries, inventions and creations made by or on behalf of
Praxis, RogCon, or by Praxis and RogCon jointly the in the performance of activities under the Agreement “Agreement Know-How”) together with Patent Rights that claim or cover Agreement Know-How “Agreement
Patents” and together with the Agreement Know-How, the “Agreement IP”). Accordingly, RogCon shall, and does hereby assign, on behalf of itself and its Affiliates and all Persons acting on its or
their behalf, to Praxis, without additional compensation, all right, title and interest, including all intellectual property rights embodied therein, in and to the Agreement IP. RogCon shall cause all Persons who perform RogCon Activities under this
Agreement or who conceive, discover, develop or otherwise make any Agreement Know-How to be under a valid, written obligation to assign all their right, title, and interest in any Agreement Know-How resulting therefrom to RogCon, except to the
extent such assignment is prohibited under Applicable Law. Upon Praxis’ request, RogCon shall execute such documents and perform such acts as may be reasonably necessary to fully effect Praxis’ sole and exclusive ownership of the Agreement
IP. As between the Parties, Praxis shall have the sole and exclusive right, but not the obligation, to file, prosecute, maintain, enforce and defend any Agreement Patents and shall bear all costs and expenses of filing, prosecuting, maintaining,
enforcing and defending the Agreement Patents and RogCon shall have no rights with respect thereto. Praxis, or its outside counsel, will provide the Coordination Committee with an update of the filing, prosecution and maintenance status for each
Agreement Patent on a periodic basis and an opportunity to review and comment on (but not approve) any such filings. 

  

	5.2	 Prosecution of RogCon Patents. Subject to Section 5.2.2, as between the Parties,
Praxis (itself or through one or more others) will have the right and responsibility to obtain, prosecute, and maintain throughout the world all Agreement Patents and RogCon Patent Rights, at Praxis’s expense. Praxis, or its outside counsel,
will provide RogCon with an update of the filing, prosecution and maintenance status for each such Patent Rights on a periodic basis and will reasonably consult with and cooperate with RogCon on the preparation, filing, prosecution and maintenance
of such Patent Rights, including providing RogCon with drafts of material filings in sufficient time to allow RogCon to review and comment before such filings are due. Praxis, or its outside counsel, will provide to RogCon copies of any material
papers relating to the filing, prosecution and maintenance of such Patent Rights promptly upon their being filed or received. Praxis may cease prosecuting or maintaining particular applications or patents within such RogCon Patent Rights in selected
jurisdictions, if Praxis determines that it is not commercially reasonable to continue such efforts (in which case the terms of Section 5.2.2 will apply). 

 

	 	5.2.1.	 Notice of Disputes. Each Party will notify the other Party within a reasonable period of time if
any action, suit, claim, dispute or proceeding concerning the RogCon Patent Rights licensed hereunder or a Product has been initiated, which, if determined adversely to a Party, would have a material adverse effect on the licenses granted by RogCon
to Praxis under this Agreement, or that would have a material adverse effect on or would materially impair either Party’s rights under this Agreement. Any information communicated pursuant to this Section 5.2.1 will be treated as
Confidential Information subject to the terms of ARTICLE 10. 

  
 10 

	 	5.2.2.	 Discontinued Patents. If, under Section 5.2, Praxis elects not to pursue or continue
the filing, prosecution or maintenance of any particular applications or patents included in the RogCon Patent Rights, or any subject matter included in the RogCon Patent Rights, in any jurisdiction, Praxis will give as much advance written notice
as reasonably practicable (but in no event less than [***] or, in the case of an applicable impending deadline, [***] prior to such deadline) to RogCon of any decision not to pursue or continue the preparation, filing, prosecution and maintenance of
such RogCon Patent Right or subject matter included in such RogCon Patent Right (a “Discontinued Patent”). In such case, RogCon may elect to continue preparation, filing, prosecution, or maintenance of the Discontinued
Patent in the select jurisdiction at its expense. Praxis will execute such documents and perform such acts as may be reasonably necessary for RogCon to continue prosecution or maintenance of the applicable Discontinued Patent. 

 

	 	5.2.3.	 Cooperation. Each Party will cooperate reasonably in the preparation, filing, prosecution,
maintenance, and defense of the RogCon Patent Rights at Praxis’ expense. Such cooperation includes (a) promptly executing all papers and instruments and requiring employees to execute such papers and instruments as reasonable and
appropriate to enable such other Party, to file, prosecute and maintain such RogCon Patent Rights in any country; and (b) promptly informing such other Party of matters that may affect the preparation, filing, prosecution or maintenance of any
such RogCon Patent Rights. 

  

	 	5.2.4.	 For purpose of this Agreement, “prosecution and maintenance” means
the filing, preparation, prosecution (including conducting all correspondence and interactions with any patent office and seeking, conducting and defending all any interferences, inter partes reviews, reissue proceedings, reexaminations, and
oppositions and similar proceedings), and maintenance thereof, including obtaining patent term extensions, regulatory exclusivity, supplemental protection certificates, or their equivalents with respect thereto. When used as a verb,
“prosecute and maintain” means to engage in prosecution and maintenance. 

  

	5.3	 Enforcement and Defense of RogCon Patents. 

 

	 	5.3.1.	 Enforcement. With respect to the RogCon Patent Rights, Praxis will have the first right, but not
the obligation, at Praxis’ expense, to remove or abate any infringement or competing product in the Field (a “Competing Infringement”). If RogCon requests that Praxis act to remove or abate a Competing Infringement, and
Praxis believes it is not commercially appropriate to take such actions, the Parties will meet and discuss in good faith such circumstances and seek to reach agreement on what appropriate steps to take to cause such Competing Infringement to end in
a commercially appropriate manner. If Praxis fails to take steps to initiate the process to remove or abate any such Competing Infringement with respect to a RogCon Patent Right within [***] following a written request from RogCon to act to remove
or abate such infringement, or earlier notifies RogCon in writing of its intent not to take such steps, RogCon will have the right to do so at its expense unless Praxis notifies RogCon of a strategic rationale in good faith for non-enforcement of
such RogCon Patent Rights. Any strategic rationale will be considered as made in good faith by Praxis if such strategic rationale is for any reason other than to avoid or reduce any payments payable to RogCon as set forth in ARTICLE 4. Praxis
will have the right, at its own expense, to be represented in any such action brought by RogCon. 

  
 11 

	 	5.3.2.	 Defense of IP. In the event that an action alleging invalidity, unenforceability or
noninfringement of any of the RogCon Patent Rights shall be brought against RogCon or Praxis (whether as an independent action or as a counterclaim of a suit filed by Praxis or RogCon pursuant to Section 5.3.1), Praxis, at its sole
option, shall have the right, within [***] after the commencement of such action, to take or regain control of the action at its own expense. If Praxis shall determine not to exercise this right, then RogCon may take over or remain as lead counsel
for the action at its sole expense. In addition, in the event that any action, suit or proceeding is brought against, or written notice or threat thereof is provided to, Praxis alleging infringement of any patent or unauthorized use or
misappropriation of technology arising out of or in connection with Praxis’ exercise of RogCon IP, Praxis shall have the right to defend, settle or compromise such action, suit or proceeding, at its own expense; provided, that Praxis shall have
no right to deny the validity of any patent, patent claim, or patent application included in the RogCon Patent Rights in any compromise or settlement of any claim or suit without the express prior written consent of RogCon. 

 

	 	5.3.3.	 Cooperation. The Party not enforcing or defending the applicable Patent Rights will provide
reasonable assistance to the other Party (at such other Party’s expense), including providing access to relevant documents and other evidence, making its employees available at reasonable business hours, and joining the action as a named party
to the extent necessary to allow the enforcing Party to bring or maintain the action or establish damages with respect to a Competing Infringement. If any Third Party asserts in writing or in any legal proceeding that any RogCon Patent Right is
unenforceable based on any term or condition of this Agreement, the Parties will amend this Agreement as may reasonably be required to effect the original intent of the Parties, including preserving the enforceability of such RogCon Patent Right.

 ARTICLE 6. 

IONIS AGREEMENT 
  

	6.1	 General. Praxis will not amend or waive any right under the Ionis Agreement in any way that would
materially adversely affect RogCon or its rights herein, except with RogCon’s prior written consent (such consent not to be unreasonably withheld, conditioned or delayed). 

 

	6.2	 Notices. In the event that Praxis receives any written notice from Ionis either (a) related
to material matters related to the Product or (b) informing Praxis that it has breached any provision of the Ionis Agreement or that Ionis intends or is threatening to terminate the Ionis Agreement, Praxis will give prompt written notice
thereof to RogCon. 

  
 12 

	6.3	 Cessation of the Ionis Agreement by Praxis. 

 

	 	6.3.1.	 Notice. Praxis agrees to provide RogCon with prompt written notice of any intention to issue a
notice of termination under the Ionis Agreement (the “Cessation Notice Period”) and will provide in such notice to RogCon the basis for any such termination. Additionally Praxis will promptly notify RogCon if it makes a
determination that it does not intend to exercise the Option under the Ionis Agreement. In either case (Praxis’ intent to terminate or not exercise the Option, a “Cessation Event”), then at RogCon’s
reasonable request Praxis and RogCon will meet to discuss the basis for Praxis’ decision and, if applicable, RogCon’s desire to accept assignment of the rights and obligations of Praxis under the Ionis Agreement. If RogCon notifies Praxis
that it desires to assume Praxis’ rights and obligations under the Ionis Agreement then, upon RogCon’s reasonable request, Praxis will provide reasonable cooperation and assistance to RogCon, including providing Ionis with copies of
documentation supplied to Praxis by RogCon regarding RogCon’s financial status, as may be necessary for RogCon to demonstrate to Ionis that RogCon meets the Assignment Criteria (as defined below). 

 

	 	6.3.2.	 Assignment. In the event of a Cessation Event and subject to RogCon meeting the criteria set
forth in Section 17.1.2(b) of the Ionis Agreement (“Assignment Criteria”) and the satisfaction of the conditions to assignment set forth in Section 17.1.2(b) of the Ionis Agreement (the
“Assignment Conditions”), at the request of RogCon, Praxis shall assign Praxis’s rights and obligations under the Ionis Agreement to RogCon. For clarity, Praxis agrees to not take any actions to directly effect a
termination of the Ionis Agreement during the Cessation Notice Period. 

 ARTICLE 7. 

REPRESENTATIONS, WARRANTIES AND COVENANTS 
  

	7.1	 Representations, Warranties and Covenants of Both Parties. Each Party hereby represents, warrants
and, where specified, covenants as of the Effective Date to the other Party that: 

  

	 	7.1.1.	 it has the power and authority and the legal right to enter into this Agreement and perform its
obligations hereunder, and that it has taken all necessary action on its part required to authorize the execution and delivery of this Agreement and the performance of its obligations hereunder; 

 

	 	7.1.2.	 this Agreement has been duly executed and delivered on behalf of such Party and constitutes a legal,
valid and binding obligation of such Party and is enforceable against it in accordance with its terms subject to the effects of bankruptcy, insolvency or other laws of general application affecting the enforcement of credit or rights and judicial
principles affecting the availability of specific performance and general principles of equity, whether enforceability is considered a proceeding at law or equity; 

 

	 	7.1.3.	 all necessary consents, approvals and authorizations of all Regulatory Authorities and other parties
required to be obtained by such Party in connection with the execution and delivery of this Agreement and the performance of its obligations hereunder have been obtained; and 

  
 13 

	 	7.1.4.	 the execution and delivery of this Agreement and the performance of such Party’s obligations
hereunder (a) do not conflict with or violate any requirement of Applicable Law or any provision of the certificate of incorporation, bylaws or any similar instrument of such Party, as applicable, in any material way, and (b) do not
conflict with, violate, or breach or constitute a default or require any consent not already obtained under, any contractual obligation or court or administrative order by which such Party is bound. 

 

	7.2	 RogCon Representations, Warranties and Covenants. RogCon hereby represents, warrants and
covenants to Praxis that: 

  

	 	7.2.1.	 As of the Effective Date, APPENDIX 2 contains a complete and accurate list of all
Patent Rights Controlled by RogCon that are necessary or reasonably useful to Develop, Manufacture, Commercialize and otherwise exploit Product in the Field; 

 

	 	7.2.2.	 As of the Effective Date, all issued Patent Rights within the RogCon Patent Rights are in full force and
effect, have been filed, prosecuted and maintained in good faith, and, to the best of RogCon’ knowledge, are valid and enforceable; 

  

	 	7.2.3.	 As of the Effective Date, RogCon has sufficient legal and/or beneficial title and ownership or right to
license (or sublicense as the case may be) with respect to the RogCon IP as is necessary to fulfill its obligations under this Agreement and to grant the rights and licenses (or sublicenses as the case may be) granted to Praxis pursuant to this
Agreement; 

  

	 	7.2.4.	 To RogCon’s actual knowledge as of the Effective Date, no actions, suits, claims, disputes or
proceedings concerning the RogCon Patent Rights are currently pending or are threatened in writing, that if determined adversely to RogCon would have an adverse effect on RogCon’s ability to grant the licenses to Praxis under this Agreement, or
that would have an adverse effect on or would impair Praxis’s right to practice the rights and licenses granted under this Agreement by RogCon to Praxis; 

 

	 	7.2.5.	 RogCon has, or will subcontract for, the requisite personnel, facilities, equipment, expertise,
experience and skill to perform its obligations under this Agreement; 

  

	 	7.2.6.	 RogCon will at all times comply with all Applicable Laws in the performance of its rights and
obligations under this Agreement; 

  

	 	7.2.7.	 As of the Effective Date, there are no agreements between RogCon and any Third Party
pursuant to which RogCon obtained rights to any Patent Rights or Know-How licensed hereunder (each, a “In-License Agreement”); 

  
 14 

	 	7.2.8.	 In the event that RogCon enters into any In-License Agreements after the Effective Date, RogCon will
(a) comply in all material respect with all terms and conditions of such In-License Agreements relating to RogCon’ rights to RogCon IP, (b) not terminate any of RogCon’s licenses or rights to RogCon IP under such In-License
Agreements; (c) not amend such In-License Agreements in any way that would limit, modify or restrict Praxis’s rights and licenses hereunder or increase or modify Praxis’s obligations hereunder, or (d) not waive any rights under
any In-License Agreements in a manner that would adversely affect the rights and licenses granted to or obligations undertaken by Praxis hereunder, except in each case (a)-(d) with Praxis’s prior written consent; and

  

	 	7.2.9.	 Except with respect to the RogCon-Ionis Agreement, as of the Effective Date, RogCon has not granted, and
during the Term will not grant, any right or license to any Third Party under the RogCon IP or relating to Product for the Field that would conflict with or limit the scope of any of the rights or licenses granted under this Agreement by RogCon to
Praxis. 

  

	7.3	 DISCLAIMER OF WARRANTY. EXCEPT FOR THE EXPRESS WARRANTIES SET FORTH IN THIS ARTICLE 7,
PRAXIS AND ROGCON MAKE NO REPRESENTATIONS AND GRANT NO WARRANTIES, EXPRESS OR IMPLIED, EITHER IN FACT OR BY OPERATION OF LAW, BY STATUTE OR OTHERWISE, AND PRAXIS AND ROGCON EACH SPECIFICALLY DISCLAIM ANY WARRANTIES, WHETHER WRITTEN OR ORAL, OR
EXPRESS OR IMPLIED, INCLUDING ANY WARRANTY OF QUALITY, MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE OR PURPOSE OR ANY WARRANTY AS TO THE VALIDITY OF ANY PATENT RIGHTS OR THE NON-INFRINGEMENT OF ANY INTELLECTUAL PROPERTY RIGHTS OF THIRD
PARTIES. 

 ARTICLE 8. 

INDEMNIFICATION; INSURANCE 
  

	8.1	 Indemnification by Praxis. Praxis will indemnify, defend and hold harmless RogCon and its
Affiliates, and its or their respective directors, officers, employees and agents (each, an “RogCon Indemnitee”), from and against any and all liabilities, damages, losses, costs and expenses, including the reasonable
fees of attorneys and other professionals (collectively, “Losses”) arising out of or resulting from any and all Third Party suits, claims, actions, proceedings or demands
(“Claims”) based on: 

  

	 	8.1.1.	 the negligence, recklessness or willful misconduct of Praxis, its Affiliates and/or others acting on
their behalf or under their authority and its or their respective directors, officers, employees and agents, in connection with Praxis’s performance of its obligations or exercise of its rights under this Agreement; 

 

	 	8.1.2.	 any breach of any representation or warranty or express covenant made by Praxis in this Agreement;

  
 15 

	 	8.1.3.	 the Development, Commercialization or manufacture of a Product by and/or on behalf of Praxis or its
Affiliates and/or others acting on their behalf or under their authority, including handling and storage by and/or on behalf of Praxis or its Affiliates and/or others acting on their behalf or under their authority; except, in each case
above, to the extent such Losses arose out of or resulted from (a) the gross negligence, recklessness or willful misconduct of any RogCon Indemnitee, (b) any breach by RogCon of any of its representations, warranties or covenants in this
Agreement, or (c) any breach of Applicable Law by any RogCon Indemnitee. 

  

	 	8.2	 Indemnification by RogCon. RogCon will indemnify, defend and hold harmless Praxis and its
Affiliates, and its or their respective directors, officers, employees and agents (each, a “Praxis Indemnitee”), from and against any and all Losses arising out of or resulting from
any and all Claims based on: 

  

	 	8.2.1.	 the negligence, recklessness or willful misconduct of RogCon and/or its Affiliates and its or their
respective directors, officers, employees and agents, in connection with RogCon’ performance of its [obligations or exercise of its rights] under this Agreement; or 

 

	 	8.2.2.	 any breach of any representation or warranty or express covenant made by RogCon in this Agreement;
except, in each case above, to the extent such Losses arose out of or resulted from (a) the gross negligence or willful misconduct of any Praxis Indemnitee, (b) any breach by Praxis of any of its representations, warranties or covenants in
this Agreement, or (c) any breach of Applicable Law by any Praxis Indemnitee. 

  

	8.3	 Procedure. If an RogCon Indemnitee or Praxis Indemnitee seeks indemnification, such RogCon
Indemnitee or Praxis Indemnitee will inform the indemnifying Party, in writing, of a Claim as soon as reasonably practicable after such RogCon Indemnitee or Praxis Indemnitee receives notice of such Claim (it being understood and agreed, however,
that any failure by an RogCon Indemnitee or Praxis Indemnitee to give such a timely notice will not relieve the indemnifying Party of its indemnification obligations under this Agreement, except to the extent that the indemnifying Party is actually
prejudiced as a result of such failure to timely give notice) and permit the indemnifying Party to assume direction and control of the defense of the Claim (including the sole right to settle it at the sole discretion of the indemnifying Party;
provided that such settlement or compromise does not admit any fault or negligence on the part of the RogCon Indemnitee or Praxis Indemnitee, as applicable, or impose any obligation on, or otherwise materially adversely affect,
the RogCon Indemnitee or Praxis Indemnitee). Notwithstanding the forgoing, the RogCon Indemnitees or Praxis Indemnitees, as applicable, will have the right to participate in such action or proceeding and to retain its own counsel but the
indemnifying Party will not be liable for any legal expenses of other counsel subsequently incurred by such RogCon Indemnitee or Praxis Indemnitee in connection with the defense thereof unless (a) the indemnifying Party has agreed to pay such
fees and expenses, (b) the indemnifying Party will have failed to employ counsel reasonably satisfactory to the RogCon Indemnitee or Praxis Indemnitee, as applicable, in a timely manner, or (c) the RogCon Indemnitee or Praxis Indemnitee
will have been advised by counsel that there are actual or potential conflicting interests between the indemnifying Party and the RogCon Indemnitee or Praxis Indemnitee, including situations in which there are one or more legal defenses available to
the RogCon Indemnitee or Praxis Indemnitee that are different from or additional to those available to the indemnifying Party. 

  
 16 

	8.4	 Insurance. Praxis will maintain at its sole cost and expense, a liability insurance program
(including clinical trials and product liability insurance) to protect against potential liabilities and risk arising out of activities to be performed under this Agreement and any agreement related hereto. At a minimum, Praxis will maintain, in
force from 30 days prior to enrollment of the first patient in a Clinical Trial involving a Product until at least one year after the completion of all applicable Clinical Trials, at its sole cost, a [***] insurance policy providing coverage of at
least [***] per claim and annual aggregate. Further, at least [***] before Praxis initiates the First Commercial Sale of any Product hereunder, Praxis will procure and maintain until at least one year after Praxis’s cessation of
Commercialization a [***] insurance policy providing coverage of the greater of (a) [***] per claim and annual aggregate or (b) in such amount and with such scope as is, at the date of the First Commercial Sale of any Product, considered
sufficient in the industry for a prudent biotechnology company, having regard to the particular Products being commercialized. As applicable, Praxis will name RogCon as an additional insured and will upon request provide RogCon with a certificate of
insurance. Praxis will promptly notify RogCon of any material change in insurance coverage or lapse in coverage. 

  

	8.5	 TO THE MAXIMUM EXTENT PERMITTED UNDER APPLICABLE LAW, EXCEPT FOR BREACHES OF SECTION 3.4
(EXCLUSIVITY COVENANTS), ARTICLE 11 (CONFIDENTIALITY) AND EACH PARTY’S INDEMNIFICATION OBLIGATIONS UNDER THIS ARTICLE 8, NEITHER ROGCON NOR PRAXIS WILL BE LIABLE TO THE OTHER FOR ANY SPECIAL, CONSEQUENTIAL, INCIDENTAL, PUNITIVE OR
INDIRECT DAMAGES ARISING FROM OR RELATING TO ANY BREACH OF THIS AGREEMENT OR THE ACTIVITIES TO BE CONDUCTED PURSUANT TO THIS AGREEMENT, EVEN IF IT HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. 

ARTICLE 9. 
 TERM;
TERMINATION 
  

	9.1	 Term; Expiration. This Agreement is effective as of the Effective Date and, unless earlier
terminated pursuant to the other provisions of this ARTICLE 9 will continue in full force and effect until the later of (a) expiration of all Patent Rights within the RogCon Patents, (b) Praxis and its Affiliates certify that they
have abandoned the Research, Development and Commercialization of Product with no intention to re-establish such activities and (c) no Third Party is obligated to pay Praxis or its Affiliates any amounts that would comprise Net Sublicense
Revenue (the “Term”). 

  
 17 

	9.2	 Termination of the Agreement. 

 

	 	9.2.1.	 Termination for Material Breach. If either Party believes that the other is in material breach of
this Agreement, then the non-breaching Party may deliver notice of such breach to the other Party. To the extent the breach is capable of being cured, the allegedly breaching Party will have [***] to cure such breach (except to the extent
such breach involves the failure to make a payment when due, which breach must be cured within [***] following such notice); provided that, in the case of a breach other than a breach involving the failure to make a payment when due, if the
breaching Party uses Commercially Reasonable Efforts to cure such breach within the applicable [***] cure period but requires additional time to cure such breach, such [***] cure period will be extended until the earlier of [***] following the
notice of breach or such time as the breaching Party is no longer using Commercially Reasonable Efforts to cure such breach. If the Party alleged to be in breach disputes such breach in good faith, then the other may not terminate unless it has been
determined in accordance with Section 12.4.2 that this Agreement was breached and the breaching Party fails to cure such breach in accordance with this Section 9.2.1 following such determination. 

 

	 	9.2.2.	 Termination by Praxis. This Agreement may be terminated by Praxis, without cause, upon [***]
written notice to RogCon, provided that no such termination shall be effective unless the Ionis Agreement is also terminated or assigned to RogCon. 

  

	 	9.2.3.	 Termination for Insolvency. Either Party may terminate this Agreement if, at any time, the other
Party files in any court or agency pursuant to any statute or regulation of any state or country a petition in bankruptcy or insolvency or for reorganization or for an arrangement or for the appointment of a receiver or trustee of the Party or of
substantially all of its assets; or if the other Party proposes a written agreement of composition or extension of substantially all of its debts; or if the other Party is served with an involuntary petition against it, filed in any insolvency
proceeding, and such petition is not dismissed within 90 days after the filing thereof; or if the other Party proposes to be or is a party to any dissolution or liquidation; or if the other Party makes an assignment of substantially all of its
assets for the benefit of creditors. Notwithstanding any further rights under Applicable Law, upon written request of the other Party, the Party filing for bankruptcy, insolvency or a similar proceeding as set forth in this Section 9.2.3
will promptly provide to such other Party all information and documents necessary to prosecute, maintain and enjoy its rights under the terms of this Agreement. 

 

	9.3	 Consequences of Termination of this Agreement. 

 

	 	9.3.1.	 Return of Information and Materials; Termination of License. Upon termination of this Agreement
by either Party pursuant to this ARTICLE 9, (a) all rights and licenses granted by RogCon to Praxis hereunder will be divested from Praxis and will revert back to RogCon and (b) each Party will return to the other Party (or destroy,
as directed by such Party) all data, files, records and other materials containing or comprising such Party’s Confidential Information. Notwithstanding the foregoing, each Party will be permitted to retain one copy of such data, files, records,
and other materials for archival purposes and for regulatory compliance. 

  
 18 

	 	9.3.2.	 Sublicense Survival. If this Agreement terminates for any reason, then, at Praxis’s request,
any Sublicense will survive and the sublicensee will, from the effective date of such termination, become a direct licensee of RogCon with respect to the rights sublicensed to the sublicensee by Praxis; so long as (a) Praxis has provided RogCon
a complete copy of the applicable Sublicense and paid RogCon any Net Sublicense Revenue associated therewith, (b) such sublicensee is not in breach of its Sublicense, (c) such sublicensee continues to comply with all of the terms of the
Sublicense, including the obligations of this Agreement imposed on sublicensee by the Sublicense, and (d) such sublicensee agrees to continue to pay directly to RogCon the portion of such sublicensee payments under the Sublicense due to RogCon
under this Agreement. Praxis agrees that it will confirm clause (a) of the foregoing in writing at the request and for the benefit of RogCon and if requested, the sublicensee. 

 

	9.4	 Accrued Rights; Surviving Obligations. 

 

	 	9.4.1.	 Accrued Rights. Termination or expiration of this Agreement for any reason will be without
prejudice to any rights or financial compensation that will have accrued to the benefit of a Party prior to such termination or expiration. Such termination or expiration will not relieve a Party from obligations that are expressly indicated to
survive the termination or expiration of this Agreement. 

  

	 	9.4.2.	 Survival. ARTICLE 1, ARTICLE 8, ARTICLE 11 (but only for the period of time
specified in Section 11.1) and ARTICLE 12 and Section 3.3, Section 4.2 (with respect to amounts due or payable under Section 9.4.1), Section 5.3 (with respect to any proceeding
ongoing as of the date of termination or expiration), Section 7.3, Section 9.3 and Section 9.4 of this Agreement will survive expiration or termination of this Agreement for any reason. 

 

	 	9.4.3.	 Rights in Bankruptcy. All rights and licenses granted under this Agreement are, for purposes of
Section 365(n) of the U.S. Bankruptcy Code (i.e., Title 11 of the U.S. Code) or analogous provisions of Applicable Law outside the United States, licenses of rights to “intellectual property” as defined under Section 101
of the U.S. Bankruptcy Code or analogous provisions of Applicable Law outside the United States. The Parties agree that each Party, as licensee of such rights under this Agreement, will retain and may fully exercise all of its rights and elections
under the U.S. Bankruptcy Code or any other provisions of Applicable Law outside the United States that provide similar protection for “intellectual property.” The Parties further agree that, in the event of the commencement of a
bankruptcy proceeding by or against a Party under the U.S. Bankruptcy Code or analogous provisions of Applicable Law outside the United States, the Party that is not subject to such proceeding will be entitled to a complete duplicate of (or complete
access to, as appropriate) such intellectual property and all embodiments of such intellectual property, which, if not already in the non-subject Party’s possession, will be promptly delivered to it upon the non-subject Party’s written
request therefor. Any agreements supplemental hereto will be deemed to be “agreements supplementary to” this Agreement for purposes of Section 365(n) of the U.S. Bankruptcy Code. 

  
 19 

 ARTICLE 10. 

[Reserved] 
 ARTICLE 11.

 CONFIDENTIALITY 
  

	11.1	 Disclosure and Use Restriction. Each Party agrees that, for so long as this Agreement is in
effect and for a period of [***] thereafter, a Party (the “Receiving Party”) receiving Confidential Information of the other Party (the “Disclosing
Party”) will (a) maintain in confidence such Confidential Information, (b) not disclose such Confidential Information except to the Receiving Party’s employees having a need-to-know such Confidential
Information, (c) not disclose such Confidential Information to any Third Party without the prior written consent of the Disclosing Party (such consent not to be unreasonably withheld, conditioned or delayed), except for disclosures expressly
permitted by this Agreement, and (d) not use such Confidential Information for any purpose except those expressly permitted by this Agreement. 

  

	11.2	 Authorized Disclosure. To the extent that it is reasonably necessary or appropriate to fulfill
its obligations or exercise its rights under this Agreement, a Party may disclose Confidential Information belonging to the other Party in the following instances: 

 

	 	11.2.1.	 filing, prosecuting and maintaining patent applications and patents in accordance with this
Agreement; 

  

	 	11.2.2.	 communicating with Regulatory Authorities as necessary for the Development or Commercialization of a
Product in a country, in accordance with this Agreement and as required in connection with any filing, application or request for Approval; provided, however, that reasonable measures will be taken to assure confidential treatment of such
information; 

  

	 	11.2.3.	 prosecuting or defending litigation or other resolution mechanisms hereunder;

  

	 	11.2.4.	 complying with Applicable Laws (including the rules and regulations of the Securities and Exchange
Commission or any national securities exchange, and compliance with tax laws and regulations) and with judicial process, if (a) in the reasonable opinion of the Receiving Party’s counsel, such disclosure is necessary for such compliance
and (b) such disclosure is made in accordance with Section 11.3 or Section 11.4 as applicable; 

  

	 	11.2.5.	 disclosure, in connection with the performance of this Agreement or exercise of its rights hereunder and
solely on a need-to-know basis, to Affiliates, potential or actual collaborators (including potential sublicensees), potential or actual investment bankers, investors, lenders, or acquirers, or employees, independent contractors or agents, and in
the case of RogCon, potential or actual assignees of the payments, in each case of whom prior to disclosure must be bound by written obligations of confidentiality and non-use no less restrictive than the obligations set forth in this ARTICLE
11; provided, however, that the Receiving Party will remain responsible for any failure by any Person who receives Confidential Information pursuant to this ARTICLE 11 to treat such Confidential Information as required under this
ARTICLE 11; and 

  
 20 

	 	11.2.6.	 in the case of Praxis, its Affiliates and sublicensees, use and disclosure of RogCon IP licensed to
Praxis under this Agreement in the ordinary course of the exercise of the rights and licenses granted to Praxis hereunder and in the performance of its duties and obligations under the Ionis Agreement. 

If Confidential Information is disclosed in accordance with this Section 11.2, such disclosure will not cause any such information
to cease to be Confidential Information except to the extent that such permitted disclosure results in a public disclosure of such information (other than by breach of this Agreement). Where reasonably possible and subject to
Section 11.3 and Section 11.4, the Receiving Party will notify the Disclosing Party of the Receiving Party’s intent to make such disclosure pursuant to the applicable subsection of this Section 11.2 before
making such disclosure to allow the Disclosing Party adequate time to take whatever action it may deem appropriate to protect the confidentiality of the information. 
  

	11.3	 Required Disclosure. A Receiving Party may disclose Confidential Information pursuant to
interrogatories, requests for information or documents, subpoena, civil investigative demand issued by a court or governmental agency or as otherwise required by Applicable Law; provided, however, that, unless legally prohibited
from doing so, the Receiving Party will notify the Disclosing Party promptly upon receipt thereof, giving (where practicable) the Disclosing Party sufficient advance notice to permit it to oppose, limit or seek confidential treatment for such
disclosure, and to file for patent protection if relevant; and provided, further, that the Receiving Party will furnish only that portion of the Confidential Information which it is advised by counsel is legally required,
whether or not a protective order or other similar order is obtained by the Disclosing Party. 

  

	11.4	 Securities Filings. If either Party proposes to file with the Securities and Exchange Commission
or the securities regulators of any state or other jurisdiction a registration statement, periodic report, or any other disclosure document which describes or refers to this Agreement under the Securities Act of 1933, as amended, the Securities
Exchange Act, of 1934, as amended, or any other applicable securities law, the Party will notify the other Party of such intention and will provide such other Party with a copy of relevant portions of the proposed filing not less than five Business
Days prior to such filing, and will seek to obtain confidential treatment of any information concerning the Agreement that such other Party requests be kept confidential (except to the extent advised by counsel that confidential treatment is not
available for such information), and will only disclose Confidential Information which it is advised by counsel is legally required to be disclosed. No such notice will be required under this Section 11.4 if the substance of the
description of or reference to this Agreement contained in the proposed filing has been included in any previous filing made by either Party hereunder or otherwise approved by the other Party. 

  
 21 

	11.5	 Injunctive Relief. The Parties understand and agree that remedies at law may be inadequate to
protect against any breach of any of the provisions of this ARTICLE 11 by either Party. Accordingly, each Party is entitled to seek injunctive relief by a court of competent jurisdiction against any action that constitutes a breach of
this ARTICLE 11. 

  

	11.6	 Press Releases. If requested by RogCon from time to time, Praxis will discuss in good faith the
right for RogCon to disclose to patient groups and others certain advances with respect to the Product. For clarity, any press release or other form of public communication or disclosure proposed to be made by RogCon in relation to the Product will
be subject to Praxis’ prior written approval, not to be unreasonably withheld, conditioned or delayed. 

 ARTICLE
12. 
 MISCELLANEOUS 
  

	12.1	 Assignment and Successors. Neither this Agreement nor any obligation of a Party hereunder may be
assigned by either Party without the consent of the other, which will not be unreasonably withheld, delayed or conditioned, except that (a) Praxis may assign this Agreement to Ionis if RogCon fails to achieve the Assignment Criteria or RogCon
notifies Praxis that it does not desire to have the Ionis Agreement assigned to it or (b) each Party may assign this Agreement and the rights, obligations and interests of such Party, in whole or in part, without the other Party’s consent,
to any of its Affiliates, to any purchaser of all or substantially all of its business or assets to which this Agreement relates or to any successor corporation resulting from any merger, consolidation, share exchange or other similar transaction.
Any purported assignment or transfer made in contravention of this Section 12.1 will be null and void. 

  

	12.2	 Severability. If any provision of this Agreement is held to be illegal, invalid or unenforceable
by a court of competent jurisdiction, such adjudication will not affect or impair, in whole or in part, the validity, enforceability or legality of any remaining portions of this Agreement. All remaining portions will remain in full force and effect
as if the original Agreement had been executed without the invalidated, unenforceable or illegal part. The Parties agree to use good faith, reasonable efforts to replace the illegal, invalid or unenforceable provision with a legal, valid and
enforceable provision that achieves similar economic and non-economic effects as the severed provision. 

  

	12.3	 Governing Law; Jurisdiction; Venue. 

 

	 	12.3.1.	 This Agreement will be governed by and construed and enforced in accordance with the laws of the
Commonwealth of Massachusetts without reference to any rules of conflicts of laws. 

  

	 	12.3.2.	 Subject to Section 12.4, each Party hereby irrevocably and unconditionally submits, for
itself and its property, to the exclusive jurisdiction of the United States District Court for the District of Massachusetts (or, if but only if such court lacks, or will not exercise, subject matter jurisdiction over the entirety of the dispute,
the Superior Court of the Commonwealth of Massachusetts sitting in the County of Suffolk). 

  
 22 

	 	12.3.3.	 Notwithstanding the foregoing or anything to the contrary herein, any dispute relating to the scope,
validity, enforceability or infringement of any Patent Rights will be governed by and construed and enforced in accordance with the patent laws of the applicable jurisdiction. 

 

	12.4	 Dispute Resolution. 

 

	 	12.4.1.	 Resolution by Senior Representatives. The Parties will seek to settle amicably any and all
disputes, controversies or claims arising out of or in connection with this Agreement. Any such dispute between the Parties will, except to the extent expressly provided otherwise herein, be promptly presented to the Chief Executive Officer of
Praxis and the Chief Executive Officer of RogCon (the “Senior Representatives”), or their respective designees, for resolution. Such Senior Representatives, or their respective designees, will meet in person or by
teleconference as soon as reasonably possible thereafter, and use their good faith efforts to agree on the resolution of the dispute, controversy or claim. If any such dispute cannot be resolved within [***] of presentation to the Senior
Representatives, or their respective designees, for resolution, then, except as stated otherwise in this Agreement, either Party may refer such dispute to binding arbitration to be conducted as set forth below in this Section 12.4. For
clarification, any dispute relating to the validity or scope of any Patent Rights will not be subject to arbitration. 

  

	 	12.4.2.	 Arbitration. 

 

	 	(a)	 Except to the extent that this Agreement identifies a Party who will have final decision-making authority over
the matter, if the Parties fail to resolve the dispute through their Senior Representatives or their respective designees, then a Party may submit such dispute to arbitration by notifying the other Party, in writing of such dispute. Within [***]
after receipt of such notice, the Parties will designate in writing a single arbitrator to resolve the dispute; provided, however, that if the Parties cannot agree on an arbitrator within such [***] period, the arbitrator will be selected by the
Boston, Massachusetts office of the JAMS. The arbitrator will be a lawyer or retired judge knowledgeable and experienced in the Applicable Law concerning the subject matter of the dispute. In any case, the arbitrator will not be an Affiliate,
employee, consultant, officer, director or stockholder of either Party, or otherwise have any current or previous relationship with either Party or their respective Affiliates. The place of arbitration will be Boston, Massachusetts. Either Party may
apply to the arbitrator for the interim injunctive relief until the arbitration award is rendered or the controversy is otherwise resolved. 

  

	 	(b)	 Within [***] after the appointment of the arbitrator, the arbitrator and the Parties will meet, and each Party
will provide to the arbitrator a written summary of all disputed issues, and such Party’s position on such disputed issues. 

  
 23 

	 	(c)	 The arbitrator will set a date for a hearing, which will be no later than [***] after the submission of the
Parties’ summary of issues under Section 12.4.2(b), for the presentation of evidence and legal argument concerning each of the issues identified by the Parties. The Parties will have the right to be represented by counsel. Except as
provided herein, the arbitration will be governed by the JAMS Streamlined Rules applicable at the time of the notice of arbitration pursuant to Section 12.4.2(a); provided, however, that the Federal Rules of Evidence will apply
with regard to the admissibility of evidence in such hearing. In any such arbitration proceeding, the Parties will be entitled to all remedies to which they would be entitled in a United States District Court and to full discovery to the same degree
permitted under the Federal Rules of Civil Procedure, including monetary damages, injunctive relief, termination of licenses or assignment of rights to a Product to either of the Parties. 

 

	 	(d)	 The arbitrator will use his or her best efforts to rule on each disputed issue within [***] after completion of
the hearing described in Section 12.4.2(c). The determination of the arbitrator as to the resolution of any dispute will be binding and conclusive on all Parties. All rulings of the arbitrator will be in writing and will be delivered to
the Parties as soon as is reasonably possible. Nothing contained herein will be construed to permit the arbitrator to award punitive, exemplary or any similar damages. The arbitrator will render a “reasoned decision” within the meaning of
the JAMS Streamlined Rules, which will include findings of fact and conclusions of law. 

  

	 	(e)	 Each Party will bear its own attorneys’ fees, costs and disbursements arising out of the arbitration, and
will pay an equal share of the fees and cost of the arbitrator; provided, however, the arbitrator will be authorized to determine whether a Party is the prevailing party, and if so, to award to that prevailing party reimbursement for any or
all of its reasonable attorneys’ fees, cost and disbursements (including, for example, expert witness fees and expenses, photocopy charges, travel expenses, etc.), and/or the fees and costs of the administrator and the arbitrator.

  

	 	(f)	 Except to the extent necessary to confirm an award or as may be required by Applicable Law, neither Party nor
an arbitrator may disclose the existence, content or results of an arbitration without the prior written consent of both Parties. No arbitration may be initiated after the date when a legal or equitable claim would otherwise be barred by the
applicable statute(s) of limitations. 

  

	12.5	 Injunctive Relief; Court Actions. Notwithstanding anything to the contrary in this Agreement,
each Party will be entitled to seek from any court of competent jurisdiction, in addition to any other remedy it may have at law or in equity, injunctive or other equitable relief in the event of an actual or threatened breach of this Agreement by
the other Party, without the posting of any bond or other security, and such an action may be filed and  

  
 24 

	 	
maintained notwithstanding any ongoing discussions between the Parties or any ongoing arbitration proceeding. The Parties agree that in the event of a threatened or actual material breach of this
Agreement, injunctive or equitable relief would be an appropriate remedy. In addition, either Party may bring an action in any court of competent jurisdiction to resolve disputes pertaining to the validity, construction, scope, enforceability,
infringement or other violations of Patent Rights or other intellectual property rights, and no such claim will be subject to arbitration pursuant to Section 12.4.2. 

 

	12.6	 Force Majeure. No Party will be held responsible to the other Party nor be deemed to be in
default under, or in breach of any provision of, this Agreement for failure or delay in performing any obligation of this Agreement when such failure or delay is due to force majeure, and without the fault or negligence of the Party so failing or
delaying. For purposes of this Agreement, force majeure means a cause beyond the reasonable control of a Party, which may include acts of God, war, terrorism, civil commotion, fire, flood, earthquake, tornado, tsunami, explosion, storm, pandemic,
epidemic or failure of public utilities or common carriers. In such event the Party so failing or delaying will immediately notify the other Party of such inability and of the period for which such inability is expected to continue. The Party giving
such notice will be excused from such of its obligations under this Agreement as it is thereby disabled from performing for so long as it is so disabled for up to a maximum of [***], after which time the Parties will negotiate in good faith any
permanent or transitory modifications of the terms of this Agreement that may be necessary to arrive at an equitable solution, unless the Party giving such notice has set out a reasonable timeframe and plan to resolve the effects of such force
majeure and executes such plan within such timeframe. To the extent possible, each Party will use reasonable efforts to minimize the duration of any force majeure. 

 

	12.7	 Notices. Any notice or request required or permitted to be given under or in connection with this
Agreement will be deemed to have been sufficiently given if in writing and personally delivered or sent by certified mail (return receipt requested), e-mail transmission (receipt verified), or overnight express courier service (signature required),
prepaid, to the Party for which such notice is intended, at the address set forth for such Party below: 

  

			
	If to RogCon, addressed to:	  	 RogCon, Inc.
 4410 Prairie Avenue

Miami, FL 33140
 Attention: Alex Nemiroff

alex@rogconbio.com

		
	If to Praxis, addressed to:	  	 Praxis Precision Medicines, Inc.
 One Broadway
Street
 16th Floor

Cambridge, MA 02142
 Attention: Chief Business Officer

stuart@praxismedicines.com

  
 25 

 or to such other address as the Party to whom notice is to be given may have furnished to
the other Party in writing in accordance herewith. Any notice given hereunder will be deemed to have been given (a) when delivered, if delivered personally or by e-mail, unless delivery occurs on a weekend or Federal holiday, in which case the
date of delivery will be the next Business Day; (b) on the next Business Day after deposit, if sent by overnight express courier service; and (c) on the third Business Day after the date of mailing, if sent by mail. 

 

	12.8	 Export Clause. Each Party acknowledges that the laws and regulations of the United States
restrict the export and re-export of commodities and technical data of United States origin. Each Party agrees that it will not export or re-export restricted commodities or the technical data of the other Party in any form without the appropriate
United States and foreign government licenses. 

  

	12.9	 Waiver. Neither Party may waive or release any of its rights or interests in this Agreement
except in writing. The failure of either Party to assert a right hereunder or to insist upon compliance with any term or condition of this Agreement will not constitute a waiver of that right or excuse a similar subsequent failure to perform any
such term or condition. No waiver by either Party of any condition or term in any one or more instances will be construed as a continuing waiver or subsequent waiver of such condition or term or of another condition or term.

  

	12.10	 Entire Agreement; Modifications. This Agreement (including the attached Appendices and Schedules)
together with any Consulting Agreement sets forth and constitutes the entire agreement and understanding between the Parties with respect to the subject matter herein, and all prior agreements, understanding, promises and representations, whether
written or oral, with respect thereto are superseded hereby. Each Party confirms that it is not relying on any representations or warranties of the other Party except as specifically set forth in this Agreement. No amendment, modification, release
or discharge will be binding upon the Parties unless in writing and duly executed by an authorized representative of each Party. 

  

	12.11	 Independent Contractors. Nothing herein will be construed to create any relationship of employer
and employee, agent and principal, partnership or joint venture between the Parties. Each Party is an independent contractor of the other. Neither Party will assume, either directly or indirectly, any liability of or for the other Party. Neither
Party will have the authority to bind or obligate the other Party, and neither Party will represent that it has such authority. 

  

	12.12	 Interpretation. Except as otherwise explicitly specified to the contrary, (a) references to
a Section, exhibit, Appendix or Schedule means a Section of, or Schedule or exhibit or Appendix to this Agreement, unless another agreement is specified, (b) the word “including” (in its various forms) means “including without
limitation,” (c) the words “will” and “shall” have the same meaning, (d) references to a particular statute or regulation include all rules and regulations thereunder and any predecessor or successor statute, rules
or regulation, in each case as amended or otherwise modified from time to time, (e) words in the singular or plural form include the plural and singular form, respectively, (f) references to a particular Person include such Person’s
successors and assigns to the extent not prohibited by this Agreement, (g) unless otherwise specified, “$” is in reference to U.S. dollars, and (h) the headings contained in this Agreement, in any exhibit or Appendix or Schedule
to this Agreement are for convenience only and will not in any way affect the construction of or be taken into consideration in interpreting this Agreement. 

  
 26 

	12.13	 Further Actions. Each Party will execute, acknowledge and deliver such further instruments, and
do all such other acts, as may be necessary or appropriate to carry out the expressly stated purposes and the clear intent of this Agreement. 

  

	12.14	 Construction. The terms of this Agreement represent the results of negotiations between the
Parties and their representatives, each of which has been represented by counsel of its own choosing, and neither of which has acted under duress or compulsion, whether legal, economic or otherwise. Accordingly, the terms of this Agreement will be
interpreted and construed in accordance with their usual and customary meanings, and each of the Parties hereby waives the application in connection with the interpretation and construction of this Agreement of any rule of law to the effect that
ambiguous or conflicting terms contained in this Agreement will be interpreted or construed against the Party whose attorney prepared the executed draft or any earlier draft of this Agreement. 

 

	12.15	 Supremacy. In the event of any express conflict or inconsistency between this Agreement and any
Schedule or Appendix hereto, the terms of this Agreement will apply. 

  

	12.16	 Counterparts. This Agreement may be signed in counterparts, each of which will be deemed an
original, notwithstanding variations in format or file designation which may result from the electronic transmission, storage and printing of copies of this Agreement from separate computers or printers. Facsimile signatures and signatures
transmitted via electronic mail in .PDF format will be treated as original signatures. 

  

	12.17	 No Benefit to Third Parties. The representations, warranties, covenants and agreements set forth
in this Agreement are for the sole benefit of the Parties hereto and their successors and permitted assigns, and they will not be construed as conferring any rights on any other parties. 

[SIGNATURE PAGES FOLLOW] 

  
 27 

 IN WITNESS WHEREOF, the Parties have caused this Agreement to be executed by their
representatives thereunto duly authorized as of the Effective Date. 
 PRAXIS PRECISION MEDICINES, INC. 

By: /s/ Kiran Reddy
                                     

Name: Kiran Reddy
                                     

Title: President & CEO
                                 

  
 28 

 IN WITNESS WHEREOF, the Parties have caused this Agreement to be executed by their
representatives thereunto duly authorized as of the Effective Date. 
 ROGCON INC. 

 

			
	By:	 	 /s/ Alex Nemiroff

	Name:	 	Alex Nemiroff
	Title:	 	Chief Executive Officer

  
 29 

 List of Appendices 

APPENDIX 1—Definitions 

APPENDIX 2—RogCon Patent Rights 

  
 30 

 Appendix 1 

DEFINITIONS 
 For purposes of this
Agreement, the following capitalized terms will have the following meanings: 
 “Affiliate” of an entity means any corporation,
firm, partnership or other entity which directly or indirectly through one or more intermediaries controls, is controlled by or is under common control with a Party to this Agreement. An entity will be deemed to control another entity if it
(a) owns, directly or indirectly, at least fifty percent (50%) of the outstanding voting securities or capital stock of such other entity, or has other comparable ownership interest with respect to any entity other than a corporation; or
(b) has the power, whether pursuant to contract, ownership of securities or otherwise, to direct the management and policies of the entity. 

“Commitment Period’ means the period beginning on the Effective Date and continuing through the First Commercial Sale of any Product
in any Major Market. 
 “Net Incentive Value” means the aggregate sale price received by Praxis or any of its Affiliates from a sale
to a Third Party of a priority review voucher awarded to Praxis or its Affiliates by the FDA or other U.S. governmental agency with respect to a Product (a “Voucher”), including all monies, cash equivalents and the
fair market value of other consideration, less (a) all reasonable out-of-pocket expenses incurred by Praxis or its Affiliate directly related to marketing and selling the Voucher, including legal fees, financial advisor fees and Third
Party broker or finder fees paid to Third Parties and (b) any amount paid or payable to Ionis with respect thereto under the Ionis Agreement. 

“Net Product Revenues” means (a) gross amounts invoiced for the sale of Product by Praxis or its Affiliates less
(b) (i) amounts paid or payable to Ionis with respect to such Product under the Ionis Agreement, (ii) amounts paid or payable to Third Parties for access to technology or intellectual property incorporated or used for such Product,
(iii) direct and indirect costs (e.g., discounts, allowances, rebates, payments to third parties, cost of goods sold, sales, general and administrative costs, and taxes, costs and expenses associated with any post-marketing studies required by
a Regulatory Authority) actually incurred by Praxis or it Affiliate and allocable to such Product in accordance with GAAP and (iv) Losses actually paid or incurred by Praxis in connection with Praxis’ defense of any Third Party challenge
to the RogCon Patent Rights or any assertion of infringement or misappropriation of any Third Party’s intellectual property rights. 
 “Net
Profits’’ means, with respect to a particular period, any and all (a) Net Product Revenues, (b) Net Sublicense Revenues, (c) Net Recoveries and (d) Net Incentive Value. 

“Net Recoveries” means (a) all damages or other monetary awards recovered or amounts received in settlement of any action for a
Competing Infringement by Praxis or its Affiliates less (b) (i) reasonable out-of-pocket costs incurred by Praxis or its Affiliates in connection with such action and (ii) amounts paid or payable to Ionis with respect thereto under
the Ionis Agreement. 

  
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 “Net Sublicense Revenues” means any consideration, cash or nonmonetary, that Praxis
receives from a sublicensee under any agreement or series of agreements that include the grant of any Sublicense (or right to receive a Sublicense), including but not limited to license fees, option fees, up-front payments, milestone payments,
royalties, royalty pre-payments, profit sharing, license maintenance fees and payments for Praxis equity above the fair market value of such equity, other than: (a) payments expressly stated in the applicable agreement to reimburse Praxis for
costs Praxis is expressly committed to incur and has incurred under a plan and budget codified in the applicable agreement (including equipment purchases and personnel actually provided by Praxis) in the development of Products which are the subject
matter of such Sublicense, (b) reimbursement of the milestone payment paid by Praxis for the milestone event in Section 4.1.4 hereunder, (c) amounts incurred with respect to the filing, prosecution or maintenance of any RogCon
Patent Rights, (d) bona fide loans or other debt obligations (unless and until forgiven), (e) amounts received from any Third Party for the purchase of equity at fair market value. If Praxis receives any non-cash Net Sublicense Revenue,
Praxis will pay RogCon, at RogCon’s election, either (i) a cash payment equal to the fair market value of RogCon’s portion of the Net Sublicense Revenue or (ii) the in-kind portion, if practicable, of the Net Sublicense Revenue.
To the extent that Net Sublicense Revenue represents an unallocated combined payment for amounts received both (1) in consideration of the grant of a Sublicense, and (2) in connection with other intellectual property, undertakings or
subject matter, such Net Sublicense Revenue for calculating payments due to RogCon will be reasonably allocated in good faith by agreement of the Parties, such agreement not to be unreasonably withheld, conditioned or delayed by either Party,
between (1) and (2) based on their relative value. For clarity, amounts received by Praxis, its Affiliates or their stockholders in a sale of all or substantially all of Praxis’s or its Affiliate’s assets or business, whether by
merger, sale of assets or otherwise, shall not be Net Sublicense Revenue. 
 “RogCon IP” means the RogCon Know-How and RogCon Patent
Rights. 
 “RogCon Know-How” means any and all Know-How Controlled by RogCon or its Affiliates at any time during the Term that is
reasonably necessary for the Research, Development or Commercialization of the Development Candidate or any [***] within the Field. 
 “RogCon
Patent Rights” means any and all Patent Rights Controlled by RogCon or its Affiliates at any time during the Term claiming (specifically or generically) (a) compositions of matter of any Development Candidate or [***] (or any
formulation thereof), (b) methods or processes for the manufacture or synthesis of any Development Candidate or [***] (or any formulation thereof) or (c) methods of use, administration or formulation of any Development Candidate or [***]
(or any formulation thereof) for the Field. 

  
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 APPENDIX 2 

[***] 

  
 33

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