<SEC-DOCUMENT>0000899243-19-007797-index.html : 20190314
<SEC-HEADER>0000899243-19-007797.hdr.sgml : 20190314
<ACCEPTANCE-DATETIME>20190314210315
ACCESSION NUMBER:		0000899243-19-007797
CONFORMED SUBMISSION TYPE:	3
PUBLIC DOCUMENT COUNT:		2
CONFORMED PERIOD OF REPORT:	20190313
FILED AS OF DATE:		20190314
DATE AS OF CHANGE:		20190314

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Ragan Paula
		CENTRAL INDEX KEY:			0001769914

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-38295
		FILM NUMBER:		19682653

	MAIL ADDRESS:	
		STREET 1:		C/O X4 PHARMACEUTICALS, INC.
		STREET 2:		955 MASSACHUSETTS AVE., 4TH FLOOR
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02139

ISSUER:		

	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

	BUSINESS ADDRESS:	
		STREET 1:		955 MASSACHUSETTS AVENUE
		STREET 2:		4TH FLOOR
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02139
		BUSINESS PHONE:		857-529-8300

	MAIL ADDRESS:	
		STREET 1:		955 MASSACHUSETTS AVENUE
		STREET 2:		4TH FLOOR
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02139

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	Arsanis, Inc.
		DATE OF NAME CHANGE:	20100920
</SEC-HEADER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>doc3.xml
<DESCRIPTION>FORM 3 SUBMISSION
<TEXT>
Document 1 - file: doc3.html

Document 1 - RAW XML: doc3.xml

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-24.1
<SEQUENCE>2
<FILENAME>attachment1.htm
<DESCRIPTION>EX-24.1 DOCUMENT
<TEXT>
Document 2 - file: attachment1.htm

</DOCUMENT>
</SEC-DOCUMENT>