<SEC-DOCUMENT>0001193125-22-001779-index.html : 20220104
<SEC-HEADER>0001193125-22-001779.hdr.sgml : 20220104
<ACCEPTANCE-DATETIME>20220104164525
ACCESSION NUMBER:		0001193125-22-001779
CONFORMED SUBMISSION TYPE:	424B3
PUBLIC DOCUMENT COUNT:		2
FILED AS OF DATE:		20220104
DATE AS OF CHANGE:		20220104

FILER:

	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:		424B3
		SEC ACT:		1933 Act
		SEC FILE NUMBER:	333-261871
		FILM NUMBER:		22506857

	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
</SEC-HEADER>
<DOCUMENT>
<TYPE>424B3
<SEQUENCE>1
<FILENAME>d278779d424b3.htm
<DESCRIPTION>424B3
<TEXT>
Document 1 - file: d278779d424b3.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>2
<FILENAME>g278779g01a03.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 2 - file: g278779g01a03.jpg

</DOCUMENT>
</SEC-DOCUMENT>