Orbimed Advisors SC 13D/A Keros Therapeutics / ORBIMED ADVISORS ownership change

Exhibit 1

JOINT FILING AGREEMENT

 The undersigned hereby agree that the Statement on Schedule 13D, dated November 20, 2020, with respect to the ordinary shares of Keros Therapeutics, Inc. is 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. Each of the undersigned agrees to be responsible for the timely filing of this Statement, and for the completeness and accuracy of the information concerning itself contained therein. This Agreement may be executed in any number of counterparts, all of which taken together shall constitute one and the same instrument.

Dated: November 20, 2020	ORBIMED ADVISORS LLC
	By:	/s/ Carl L. Gordon
		Name: Carl L. Gordon
		Title: Member
	ORBIMED CAPITAL GP VII LLC
	By:	ORBIMED ADVISORS LLC, its managing member
	By:	/s/ Carl L. Gordon
		Carl L. Gordon
		Title: Member of OrbiMed Advisors LLC
	ORBIMED GENESIS GP LLC
	By: / ORBIMED ADVISORS LLC, its managing member
	By:	/s/ Carl L. Gordon
		Carl L. Gordon
		Title: Member of OrbiMed Advisors LLC
	ORBIMED CAPITAL LLC
	By:	/s/ Carl L. Gordon
		Carl L. Gordon
		Title: Member