Achilles Therapeutics (ACHL) SC 13G Achilles Therapeutics / Artal International S.C.A. ownership change

EXHIBIT 1

JOINT FILING AGREEMENT

The undersigned agree that the statement on Schedule 13G with respect to the Ordinary Shares, nominal value £0.001 per share, of Achilles Therapeutics plc, dated as of April 15, 2021, is, and any amendments thereto signed by each of the undersigned shall be, filed on behalf of each of them pursuant to and in accordance with the provisions of Rule 13d-1(k) under the Securities Exchange Act of 1934, as amended.

INVUS PUBLIC EQUITIES, L.P.
By:	INVUS PUBLIC EQUITIES ADVISORS, LLC, its general partner
By:	/s/ Raymond Debbane
Name:	Raymond Debbane
Title:	President
INVUS PUBLIC EQUITIES ADVISORS, LLC
By:	/s/ Raymond Debbane
Name:	Raymond Debbane
Title:	President
ARTAL TREASURY LIMITED
By:	/s/ Keith Le Poidevin
Name:	Keith Le Poidevin
Title:	Director
ARTAL INTERNATIONAL S.C.A.
By:	ARTAL INTERNATIONAL MANAGEMENT S.A., its managing partner
By:	/s/ Anne Goffard
Name:	Anne Goffard
Title:	Managing Director
ARTAL INTERNATIONAL MANAGEMENT S.A.
By:	/s/ Anne Goffard
Name:	Anne Goffard
Title:	Managing Director
ARTAL GROUP S.A.
By:	/s/ Anne Goffard
Name:	Anne Goffard
Title:	Authorized Person

WESTEND S.A.
By:	/s/ Anne Goffard
Name:	Anne Goffard
Title:	Managing Director
STICHTING ADMINISTRATIEKANTOOR WESTEND
By:	/s/ Amaury Wittouck
Name:	Amaury Wittouck
Title:	Sole Member of the Board
MR. AMAURY WITTOUCK
By:	/s/ Amaury Wittouck
Dated: April 15, 2021