<SEC-DOCUMENT>0001193125-19-106621-index.html : 20190415
<SEC-HEADER>0001193125-19-106621.hdr.sgml : 20190415
<ACCEPTANCE-DATETIME>20190415164133
ACCESSION NUMBER:		0001193125-19-106621
CONFORMED SUBMISSION TYPE:	8-K
PUBLIC DOCUMENT COUNT:		8
CONFORMED PERIOD OF REPORT:	20190412
ITEM INFORMATION:		Entry into a Material Definitive Agreement
ITEM INFORMATION:		Other Events
ITEM INFORMATION:		Financial Statements and Exhibits
FILED AS OF DATE:		20190415
DATE AS OF CHANGE:		20190415

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:		8-K
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-38295
		FILM NUMBER:		19749010

	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>8-K
<SEQUENCE>1
<FILENAME>d734812d8k.htm
<DESCRIPTION>8-K
<TEXT>
Document 1 - file: d734812d8k.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-1.1
<SEQUENCE>2
<FILENAME>d734812dex11.htm
<DESCRIPTION>EX-1.1
<TEXT>
Document 2 - file: d734812dex11.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-4.1
<SEQUENCE>3
<FILENAME>d734812dex41.htm
<DESCRIPTION>EX-4.1
<TEXT>
Document 3 - file: d734812dex41.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-4.2
<SEQUENCE>4
<FILENAME>d734812dex42.htm
<DESCRIPTION>EX-4.2
<TEXT>
Document 4 - file: d734812dex42.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-5.1
<SEQUENCE>5
<FILENAME>d734812dex51.htm
<DESCRIPTION>EX-5.1
<TEXT>
Document 5 - file: d734812dex51.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-99.1
<SEQUENCE>6
<FILENAME>d734812dex991.htm
<DESCRIPTION>EX-99.1
<TEXT>
Document 6 - file: d734812dex991.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>7
<FILENAME>g734812g0413042427073.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 7 - file: g734812g0413042427073.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>8
<FILENAME>g734812g0413042427183.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 8 - file: g734812g0413042427183.jpg

</DOCUMENT>
</SEC-DOCUMENT>