SECURITIES PURCHASE AGREEMENT This Securities Purchase Agreement (this Agreement ) is dated as of

SECURITIES PURCHASE AGREEMENT

This Securities Purchase Agreement (this Agreement ) is dated as of September 30, 2021, between Trevi Therapeutics,

Inc., a Delaware corporation (the Company ), and each purchaser identified on the signature pages hereto (each, including its successors and assigns, a Purchaser and collectively, the

WHEREAS, subject to the terms and conditions set forth in this Agreement and pursuant to

Section 4(a)(2) of the Securities Act of 1933, as amended (the Securities Act ), and Regulation D promulgated thereunder ( Regulation D ), the Company desires to issue and sell to each Purchaser, and each

Purchaser, severally and not jointly, desires to purchase from the Company, Securities of the Company as more fully described in this Agreement;

WHEREAS, contemporaneously with the execution of this Agreement, the parties hereto will execute and deliver the Registration Rights Agreement

(as defined below), pursuant to which the Company will agree to provide certain registration rights under the Securities Act, and the rules and regulations promulgated thereunder, and applicable state securities laws; and

NOW, THEREFORE, IN CONSIDERATION of the mutual covenants contained in this Agreement, and for other good and valuable consideration the

receipt and adequacy of which are hereby acknowledged, the Company and each Purchaser agree as follows:

Definitions. In addition to the terms defined elsewhere in this Agreement, for all purposes of this Agreement, the following terms have the meanings set forth in this Section 1.1:

3.5-Year Common Stock Warrant means the Common Stock Purchase Warrants delivered to

the Purchasers at the Closing in accordance with Section 2.2(a) hereof, which Warrants shall be exercisable commencing immediately upon issuance and have a term equal to three and one half (3.5) years, in the form of Exhibit A-1 attached hereto.

Warrant means the Common Stock Purchase Warrants delivered to the Purchasers at the Closing in accordance with Section 2.2(a) hereof, which Warrants shall be exercisable commencing immediately upon issuance and have a term equal to

seven (7) years, in the form of Exhibit A-2 attached hereto.

Acquiring Person shall have the meaning ascribed to such term in Section 4.5.

Action shall have the meaning ascribed to such term in Section 3.1(j).

Affiliate means any Person that, directly or indirectly through one or more intermediaries, controls or is

controlled by or is under common control with a Person, as such terms are used in and construed under Rule 405 under the Securities Act.

Board of Directors means the board of directors of the Company.

Business Day means any day except any Saturday, any

Sunday, any day which is a federal legal holiday in the United States or any day on which banking institutions in the State of New York are authorized or required by law or other governmental action to close.

Closing means the closing of the purchase and sale of the Securities pursuant to Section 2.1.

Closing Date means the Trading Day on which all of the Transaction Documents have been executed and

delivered by the applicable parties thereto, and all conditions precedent to (i) the Purchasers obligations to pay the Subscription Amount and (ii) the Company s obligations to deliver the Securities, in each case, have been

satisfied or waived, but in no event later than the second (2nd) Trading Day following the date hereof.

Commission means the United States Securities and Exchange Commission.

Common Stock means the common stock of the Company, par value $0.001 per share, and any other class of

securities into which such securities may hereafter be reclassified or changed.

Equivalents means any securities of the Company or the Subsidiaries which would entitle the holder thereof to acquire at any time Common Stock, including, without limitation, any debt, preferred stock, right, option, warrant or other

instrument that is at any time convertible into or exercisable or exchangeable for, or otherwise entitles the holder thereof to receive, Common Stock.

Common Stock Warrants means, collectively, the 3.5-Year Common Stock

Warrants and the 7-Year Common Stock Warrants.

Common Stock Warrant

Shares means the shares of Common Stock issuable upon exercise of the Common Stock Warrants.

Units means each Common Unit consisting of (a) one Share, (b) a 3.5-Year Common Stock Warrant to purchase one Common Stock Warrant Share and (c) a

7-Year Common Stock Warrant to purchase one Common Stock Warrant Share.

Common Unit Purchase Price equals $1.620 per each Common Unit, subject to adjustment for reverse and forward

stock splits, stock dividends, stock combinations and other similar transactions of the Common Stock that occur after the date of this Agreement.

Common Unit Subscription Amount means, as to each Purchaser, the aggregate amount to be paid for the Common

Units hereunder as specified below such Purchaser s name on the signature page of this Agreement and next to the heading Common Unit Subscription Amount, in United States dollars and in immediately available funds.

Company Counsel means Wilmer Cutler Pickering Hale and Dorr LLP, with offices located at 60 State Street,

Disclosure Schedules means the Disclosure Schedules of

the Company delivered concurrently herewith.

Disclosure Time means, (i) if this Agreement is

signed on a day that is not a Trading Day or after 9:00 a.m. (New York City time) and before midnight (New York City time) on any Trading Day, 9:01 a.m. (New York City time) on the Trading Day immediately following the date hereof, unless otherwise

instructed as to an earlier time by the Placement Agent and the Company, and (ii) if this Agreement is signed between midnight (New York City time) and 9:00 a.m. (New York City time) on any Trading Day, no later than 9:01 a.m. (New York City

time) on the date hereof, unless otherwise instructed as to an earlier time by the Placement Agent.

Date shall have the meaning ascribed to such term in Section 3.1(s).

the Securities Exchange Act of 1934, as amended, and the rules and regulations promulgated thereunder.

Issuance means the issuance of (a) shares of Common Stock or options to employees, officers or directors of, or consultants or advisors to, the Company pursuant to the Company s 2019 Stock Incentive Plan, the Company s 2019

Employee Stock Purchase Plan or any other stock incentive plan duly adopted for such purpose, by the Board of Directors or a duly authorized committee of the Board of Directors, (b) shares of Common Stock pursuant to the exercise of options in

existence as of the date hereof, (c) securities upon the exercise or exchange of or conversion of any Securities issued hereunder and/or other securities exercisable or exchangeable for or convertible into shares of Common Stock issued and

outstanding on the date of this Agreement, provided that such securities have not been amended since the date of this Agreement to increase the number of such securities or to decrease the exercise price, exchange price or conversion price of such

securities (other than in connection with stock splits, combinations or the like) or to extend the term of such securities, (d) shares of Common Stock and warrants to purchase Common Stock issued to officers or directors of the Company or their

Affiliates or any stockholder, member, partner or affiliate thereof on or before the date three weeks after the Closing Date for an aggregate purchase price of up to $5,000,000 and on terms no less favorable to the Company than the Securities and

the sale of the Securities hereunder and the issuance of any securities upon the exercise, exchange or conversion thereof, and (e) securities issued pursuant to acquisitions or strategic transactions approved by the Board, provided that such

securities are issued as restricted securities (as defined in Rule 144) and carry no registration rights that require or permit the filing of any registration statement in connection therewith during the prohibition period in

Section 4.10(a) herein, and provided that any such issuance shall only be to a Person (or to the equityholders of a Person) which is, itself or through its subsidiaries, an operating company or an owner of an asset in a business synergistic

with the business of the Company and shall provide to the Company additional benefits in addition to the investment of funds, but shall not include a transaction in which the Company is issuing securities primarily for the purpose of raising capital

or to an entity whose primary business is investing in securities.

FCPA means the Foreign Corrupt

Practices Act of 1977, as amended.

FDA shall have the meaning ascribed to such term in

FDCA shall have the meaning ascribed to such term in Section 3.1(hh).

GAAP shall have the meaning ascribed to such term in Section 3.1(h).

Indebtedness shall have the meaning ascribed to such term in Section 3.1(aa).

Intellectual Property Rights shall have the meaning ascribed to such term in Section 3.1(p).

Legend Removal Date shall have the meaning ascribed to such term in Section 4.1(c).

Liens means a lien, charge, pledge, security interest, encumbrance, right of first refusal, preemptive right

or other restriction.

Material Adverse Effect shall have the meaning assigned to such term in

Material Permits shall have the meaning ascribed to such term in

Person means an individual or corporation, partnership, trust, incorporated or

unincorporated association, joint venture, limited liability company, joint stock company, government (or an agency or subdivision thereof) or other entity of any kind.

Pharmaceutical Product shall have the meaning ascribed to such term in Section 3.1(hh).

Placement Agent means, collectively, Stifel, Nicolaus & Company, Incorporated and

Needham & Company, LLC.

Pre-Funded Units means each Pre-Funded Unit consisting of (a) one Pre-Funded Warrant to purchase one Pre-Funded Warrant Share, (b) a 3.5-Year Common Stock Warrant to purchase one Common Stock Warrant Share and (c) a 7-Year Common Stock Warrant to purchase one Common Stock Warrant Share.

Pre-Funded Unit Purchase Price equals $1.619, subject to adjustment

for reverse and forward stock splits, stock dividends, stock combinations and other similar transactions of the Common Stock that occur after the date of this Agreement.

Pre-Funded Unit Subscription Amount means, as to each Purchaser, the

aggregate amount to be paid for the Pre-Funded Units purchased hereunder as specified below such Purchaser s name on the signature page of this Agreement and next to the heading Pre-Funded Unit Subscription Amount, in United States dollars and in immediately available funds.

Warrants means, collectively, the Pre-Funded Common Stock purchase warrants delivered to the Purchasers at the Closing in accordance with Section 2.2(a) hereof, which Pre-Funded Warrants shall be exercisable immediately and shall expire when exercised in full, in the form of Exhibit A-3 attached hereto.

Pre-Funded Warrant Shares means the shares of Common Stock issuable

upon exercise of the Pre-Funded Warrants.

action, claim, suit, investigation or proceeding (including, without limitation, an informal investigation or partial proceeding, such as a deposition), whether commenced or threatened.

Public Information Failure shall have the meaning ascribed to such term in Section 4.2(b).

Public Information Failure Payments shall have the meaning ascribed to such term in Section 4.2(b).

Purchaser Party shall have the meaning ascribed to such term in Section 4.7.

Registration Rights Agreement means the Registration Rights Agreement, dated on or about the date hereof,

among the Company and the Purchasers, in the form of Exhibit B attached hereto.

Statement means a registration statement filed in accordance with the Registration Rights Agreement, with respect to the resale by the Purchasers of the Shares and the Warrant Shares.

Required Approvals shall have the meaning ascribed to such term in Section 3.1(e).

Requisite Purchaser Vote shall have the meaning ascribed to such term in Section 5.5.

Rule 144 means Rule 144 promulgated by the Commission pursuant to the Securities Act, as such Rule may be

amended or interpreted from time to time, or any similar rule or regulation hereafter adopted by the Commission having substantially the same purpose and effect as such Rule.

Rule 424 means Rule 424 promulgated by the Commission pursuant to the Securities Act, as such Rule may be

amended or interpreted from time to time, or any similar rule or regulation hereafter adopted by the Commission having substantially the same purpose and effect as such Rule.

SEC Reports shall have the meaning ascribed to such term in Section 3.1(h).