Common Stock, $0.001 par value

Trevi Therapeutics, Inc.

195 Church Street, 16th Floor, New Haven, CT, 06510

New Enterprise Associates 16, L.P. ("NEA 16") and NEA 18 Venture Growth Equity, L.P. ("NEA 18 VGE" and together with NEA 16, the "Funds"); NEA Partners 16, L.P. ("NEA Partners 16"), which is the sole general partner of NEA 16; NEA Partners 18 VGE, L.P. ("NEA Partners 18 VGE" and together with NEA Partners 16, the "GPLPs"), which is the sole general partner of NEA 18 VGE; NEA 16 GP, LLC ("NEA 16 LLC"), which is the sole general partner of NEA Partners 16; and NEA 18 VGE GP, LLC ("NEA 18 VGE LLC" and together with NEA 16 LLC, the "GP LLCs"), which is the sole general partner of NEA Partners 18 VGE; Forest Baskett ("Baskett"), Ali Behbahani ("Behbahani"), Carmen Chang ("Chang"), Anthony A. Florence, Jr. ("Florence"), Mohamad H. Makhzoumi ("Makhzoumi"), Scott D. Sandell ("Sandell") and Paul Walker ("Walker") (together, the "Managers"). Behbahani, Chang, Florence, Makhzoumi, Sandell and Walker (the "Plural Managers") are managers of NEA 16 LLC and NEA 18 VGE LLC. Baskett is a manager of NEA 16 LLC. The persons named in this Item 2 are referred to individually herein as a "Reporting Person" and collectively as the "Reporting Persons" and the GPLPs and the GP LLCs are referred to herein as the "Control Entities."

The address of the principal business office of each Fund, each Control Entity and Sandell is New Enterprise Associates, 1954 Greenspring Drive, Suite 600, Timonium, MD 21093. The address of the principal business office of Baskett, Behbahani, Chang, Makhzoumi and Walker is New Enterprise Associates, 2855 Sand Hill Road, Menlo Park, CA 94025. The address of the principal business office of Florence is New Enterprise Associates, 104 5th Avenue, 19th Floor, New York, NY 10011.

The principal business of NEA 16 and NEA 18 VGE is to invest in and assist growth-oriented businesses located principally in the United States. The principal business of NEA Partners 16 is to act as the sole general partner of NEA 16. The principal business of NEA Partners 18 VGE is to act as the sole general partner of NEA 18 VGE. The principal business of NEA 16 LLC is to act as the sole general partner of NEA Partners 16. The principal business of NEA 18 VGE LLC is to act as the sole general partner of NEA Partners 18 VGE. The principal business of each of the Managers is to manage the Control Entities, NEA 16, NEA 18 VGE and a number of affiliated partnerships with similar businesses, as applicable.

During the five years prior to the date hereof, none of the Reporting Persons has been convicted in a criminal proceeding or has been a party to a civil proceeding ending in a judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws or finding any violation with respect to such laws.

NEA 16 LLC and NEA 18 VGE LLC are each a limited liability company organized under the laws of the State of Delaware. NEA 16, NEA 18 VGE, NEA Partners 16 and NEA Partners 18 VGE are limited partnerships organized under the laws of the State of Delaware. Each of the Managers is a United States citizen.

As of March 20, 2025, NEA 16 is the record owner of 10,421,428 shares of Common Stock and may be deemed to beneficially hold 3,703,704 shares of Common Stock underlying the NEA 16 Warrants (collectively, the "NEA 16 Shares"). As the general partner of NEA 16, NEA Partners 16 may be deemed to own beneficially the NEA 16 Shares. As the sole general partner of NEA Partners 16, NEA 16 LLC may be deemed to own beneficially the NEA 16 Shares. NEA 18 VGE is the record owner of 948,948 shares of Common Stock (the "NEA 18 VGE Shares"). As the general partner of NEA 18 VGE, NEA Partners 18 VGE may be deemed to own beneficially the NEA 18 VGE Shares. As the general partner of NEA Partners 18 VGE, NEA 18 VGE LLC may be deemed to own beneficially the NEA 18 VGE Shares. The NEA 16 Shares and the NEA 18 VGE Shares are referred to herein as the "Firm Shares." By virtue of their relationship as affiliated entities, whose Control Entities have overlapping individual controlling persons, each of the Funds may be deemed to share the power to direct the disposition and vote of the Firm Shares. As general partners of the Funds, each of the GPLPs may also be deemed to own beneficially the Firm Shares. As the sole general partner of NEA Partners 16, NEA 16 LLC may also be deemed to own beneficially the Firm Shares. As the sole general partner of NEA Partners 18 VGE, NEA 18 VGE LLC may also be deemed to own beneficially the Firm Shares. As individual managers of NEA 16 LLC and NEA 18 VGE LLC, each of the Plural Managers may be deemed to own beneficially all of the Firm Shares. As an individual manager of NEA 16 LLC, Baskett may be deemed to own beneficially the NEA 16 Shares. Each Reporting Person disclaims beneficial ownership of the Firm Shares other than those shares which such person owns of record. The percentage of outstanding Common Stock of the Issuer which may be deemed to be beneficially owned by each Reporting Person is set forth on Line 13 of such Reporting Person's cover sheet. Such percentage was calculated for each Reporting Person based on 100,385,933 shares of Common Stock, which include (i) the 96,682,229 shares of Common Stock reported by the Issuer to be outstanding as of March 14, 2025 on the Issuer's Form 10-K filed with the Securities and Exchange Commission on March 18, 2025 and (ii) the NEA 16 Warrants.

Regarding the number of shares as to which such person has: (i) sole power to vote or to direct the vote: See line 7 of cover sheets (ii) shared power to vote or to direct the vote: See line 8 of cover sheets (iii) sole power to dispose or to direct the disposition: See line 9 of cover sheets (iv) shared power to dispose or to direct the disposition: See line 10 of cover sheets.

None of the Reporting Persons have effected any transaction in the last 60 days.

No other person is known to have the right to receive or the power to direct the receipt of dividends from, or any proceeds from the sale of, Common Stock beneficially owned by any of the Reporting Persons.

Not applicable.