<SEC-DOCUMENT>0000000000-19-001672-index.html : 20190429
<SEC-HEADER>0000000000-19-001672.hdr.sgml : 20190429
<ACCEPTANCE-DATETIME>20190208172515
<PRIVATE-TO-PUBLIC>
ACCESSION NUMBER:		0000000000-19-001672
CONFORMED SUBMISSION TYPE:	UPLOAD
PUBLIC DOCUMENT COUNT:		2
FILED AS OF DATE:		20190208

FILED FOR:		

	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:		UPLOAD

	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
PUBLIC REFERENCE ACCESSION NUMBER:		0001193125-19-017208 [HTML]
</SEC-HEADER>
<DOCUMENT>
<TYPE>LETTER
<SEQUENCE>1
<FILENAME>filename1.pdf
<TEXT>
Document 1 - file: filename1.pdf

</DOCUMENT>
<DOCUMENT>
<TYPE>TEXT-EXTRACT
<SEQUENCE>2
<FILENAME>filename2.txt
<TEXT>
Document 2 - file: filename2.txt

</DOCUMENT>
</SEC-DOCUMENT>