<SEC-DOCUMENT>0001193805-21-000212-index.html : 20210212
<SEC-HEADER>0001193805-21-000212.hdr.sgml : 20210212
<ACCEPTANCE-DATETIME>20210212123917
ACCESSION NUMBER:		0001193805-21-000212
CONFORMED SUBMISSION TYPE:	SC 13G/A
PUBLIC DOCUMENT COUNT:		1
FILED AS OF DATE:		20210212
DATE AS OF CHANGE:		20210212
GROUP MEMBERS:		DEERFIELD MANAGEMENT COMPANY, L.P.
GROUP MEMBERS:		DEERFIELD MGMT, L.P.
GROUP MEMBERS:		DEERFIELD PARTNERS, L.P.
GROUP MEMBERS:		DEERFIELD SPECIAL SITUATIONS FUND, L.P.

SUBJECT COMPANY:	

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			X4 Pharmaceuticals, Inc
		CENTRAL INDEX KEY:			0001501697
		STANDARD INDUSTRIAL CLASSIFICATION:	BIOLOGICAL PRODUCTS (NO DIAGNOSTIC SUBSTANCES) [2836]
		IRS NUMBER:				273181608
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		SC 13G/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	005-90199
		FILM NUMBER:		21624851

	BUSINESS ADDRESS:	
		STREET 1:		61 NORTH BEACON STREET
		STREET 2:		4TH FLOOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02134
		BUSINESS PHONE:		857-529-8300

	MAIL ADDRESS:	
		STREET 1:		61 NORTH BEACON STREET
		STREET 2:		4TH FLOOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02134

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	Arsanis, Inc.
		DATE OF NAME CHANGE:	20100920

FILED BY:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Flynn James E
		CENTRAL INDEX KEY:			0001352546

	FILING VALUES:
		FORM TYPE:		SC 13G/A

	MAIL ADDRESS:	
		STREET 1:		780 THIRD AVENUE
		STREET 2:		37TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10017
</SEC-HEADER>
<DOCUMENT>
<TYPE>SC 13G/A
<SEQUENCE>1
<FILENAME>e620285_sc13ga-x4.htm
<TEXT>
Document 1 - file: e620285_sc13ga-x4.htm

</DOCUMENT>
</SEC-DOCUMENT>