EXHBIIT A

JOINT FILING AGREEMENT

The undersigned hereby agree that the statement on Schedule 13G with respect to the shares of common stock, par value $0.001 per share, of Catabasis Pharmaceuticals, Inc. dated as of February 13, 2019 is, and any amendments thereto signed by each of the undersigned shall be, filed on behalf of each of us pursuant to and in accordance with the provisions of Rule 13d-1(k) under the Securities Exchange Act of 1934, as amended.

CORRIENTE ADVISORS, LLC

/s/ Matthew Gilman

Chief Financial Officer

CORRIENTE MASTER FUND II, LP

/s/ Matthew Gilman

Chief Financial Officer of Corriente Advisors, LLC, the Investment Manager of Corriente Master Fund II, LP

MARK L. HART III

/s/ Mark L. Hart III

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