<SEC-DOCUMENT>0001104659-21-019848-index.html : 20210210
<SEC-HEADER>0001104659-21-019848.hdr.sgml : 20210210
<ACCEPTANCE-DATETIME>20210210163154
ACCESSION NUMBER:		0001104659-21-019848
CONFORMED SUBMISSION TYPE:	SC 13G
PUBLIC DOCUMENT COUNT:		2
FILED AS OF DATE:		20210210
DATE AS OF CHANGE:		20210210
GROUP MEMBERS:		PETER KOLCHINSKY
GROUP MEMBERS:		RA CAPITAL HEALTHCARE FUND, L.P.
GROUP MEMBERS:		RAJEEV SHAH

SUBJECT COMPANY:	

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Keros Therapeutics, Inc.
		CENTRAL INDEX KEY:			0001664710
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				000000000
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		SC 13G
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	005-91484
		FILM NUMBER:		21614352

	BUSINESS ADDRESS:	
		STREET 1:		99 HAYDEN AVENUE, SUITE 120 (BLD E)
		STREET 2:		LEDGEMONT TECHNOLOGY CENTER
		CITY:			LEXINGTON
		STATE:			MA
		ZIP:			02421
		BUSINESS PHONE:		617-513-8774

	MAIL ADDRESS:	
		STREET 1:		99 HAYDEN AVENUE, SUITE 120 (BLD E)
		STREET 2:		LEDGEMONT TECHNOLOGY CENTER
		CITY:			LEXINGTON
		STATE:			MA
		ZIP:			02421

FILED BY:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			RA CAPITAL MANAGEMENT, L.P.
		CENTRAL INDEX KEY:			0001346824
		IRS NUMBER:				830406777
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		SC 13G

	BUSINESS ADDRESS:	
		STREET 1:		200 BERKELEY STREET, 18TH FLOOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116
		BUSINESS PHONE:		617-778-2500

	MAIL ADDRESS:	
		STREET 1:		200 BERKELEY STREET, 18TH FLOOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	RA CAPITAL MANAGEMENT, LLC
		DATE OF NAME CHANGE:	20051213
</SEC-HEADER>
<DOCUMENT>
<TYPE>SC 13G
<SEQUENCE>1
<FILENAME>tm216120d1_sc13g.htm
<DESCRIPTION>SC 13G
<TEXT>
Document 1 - file: tm216120d1_sc13g.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-99.1
<SEQUENCE>2
<FILENAME>tm216120d1_ex1.htm
<DESCRIPTION>EXHIBIT 99.1
<TEXT>
Document 2 - file: tm216120d1_ex1.htm

</DOCUMENT>
</SEC-DOCUMENT>