TRVI Trevi Therapeutics Inc

2019 Stock Incentive Plan

2019 Employee Stock Purchase Plan

(Full title of the plan)

Jennifer Good

President and Chief Executive Officer

Trevi Therapeutics, Inc.

195 Church Street, 14th Floor

New Haven, Connecticut 06510

(Name and address of agent for service)

(203) 304-2499

(Telephone number, including area code, of agent for service)

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act. ☒

Statement of Incorporation by Reference

This Registration Statement on Form S-8, relating to the 2019 Stock Incentive Plan and the 2019 Employee Stock Purchase Plan of Trevi Therapeutics, Inc. (the “Registrant”), is being filed for the purpose of registering additional securities of the same class as other securities for which a Registration Statement on Form S-8 has previously been filed and is effective. Pursuant to General Instruction E to Form S-8, except as otherwise set forth below, this Registration Statement incorporates by reference (i) the contents of the Registration Statement on Form S-8, File No. 333-231260, relating to the 2012 Stock Incentive Plan, as amended, of the Registrant, the 2019 Stock Incentive Plan of the Registrant (the “2019 Plan”), and the 2019 Employee Stock Purchase Plan of the Registrant (the “2019 ESPP”), filed by the Registrant with the Securities and Exchange Commission on May 7, 2019, (ii) the contents of the Registration Statement on Form S-8, File No. 333-237193, relating to the 2019 Plan and the 2019 ESPP, filed by the Registrant with the Securities and Exchange Commission on March 16, 2020, and (iii) the contents of the Registration Statement on Form S-8, File No. 333-257729, relating to the 2019 Plan and the 2019 ESPP, filed by the Registrant with the Securities and Exchange Commission on July 7, 2021.