UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Final Amendment No. 1)*

Astria Therapeutics, Inc.

(Name of Issuer)

Common Stock, Par Value $0.001

(Title of Class of Securities)

04635X102

(CUSIP Number)

James J. Moloney

Gibson, Dunn & Crutcher LLP

3161 Michelson Drive

Irvine, CA 92612

(949) 451-3800

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

September 20, 2021

(Date of Event Which Requires Filing of This Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.  ☐

Note: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See Rule 13d-7 for other parties to whom copies are to be sent.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

CUSIP No. 04635X102

CUSIP No. 04635X102

This Amendment No. 1 amends and supplements the Statement on Schedule 13D (the “Original Schedule 13D”) filed by Viridian, LLC (“Viridian”) and Lazarus Life Sciences I, LLC (“Lazarus” and, together with Viridian, the “Reporting Persons”) on June 17, 2021, with respect to the shares of common stock, $0.001 par value per share (the “Common Stock”) of Astria Therapeutics, Inc., a Delaware corporation (the “Company” or the “Issuer”), with principal executive offices located at 100 High Street, 28th Floor, Boston, MA 02110.

On August 19, 2021, the Company amended its certificate of incorporation to effect a one-for-six reverse stock split of the Common Stock. Effective as of September 8, 2021, the Company amended its certificate of incorporation to effect a change of the Company’s name from “Catabasis Pharmaceuticals, Inc.” to “Astria Therapeutics, Inc.”

Capitalized terms used herein but not otherwise defined herein have the meanings given to them in the Schedule 13D. Except as set forth herein, the Original Schedule 13D is unmodified and remains in full force and effect. This is the final amendment to the Original Schedule 13D and constitutes an exit filing for the Reporting Persons.

(a) As of September 20, 2021, the Reporting Persons no longer own any shares of the Common Stock.

(c) The following table sets forth all transactions with respect to shares of Common Stock effected during the past 60 days by any of the Reporting Persons.

(e) The Reporting Persons ceased to be the beneficial owners of more than five percent of the Common Stock on September 20, 2021. Accordingly, this Amendment No. 1 constitutes an exit filing for the Reporting Persons.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Dated: September 22, 2021