XFOWW X4 Pharmaceuticals Inc (PK)

1	Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only)   Cormorant Global Healthcare GP, LLC
2	Check the Appropriate Box if a Member of a Group (See Instructions)
	(a) [ ]
	(b) [x]
3	SEC Use Only
4	Citizenship or Place of Organization.   Delaware
Number of Shares Beneficially Owned by Each Reporting Person With		5 Sole Voting Power   0 shares
		6 Shared Voting Power   331,578 shares   Refer to Item 4 below.
		7 Sole Dispositive Power   0 shares
		8 Shared Dispositive Power   331,578 shares Refer to Item 4 below.
9	Aggregate Amount Beneficially Owned by Each Reporting Person   331,578 shares Refer to Item 4 below.
10	Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions)     [ ] N/A
11	Percent of Class Represented by Amount in Row (9)*   2.03% Refer to Item 4 below.
12	Type of Reporting Person (See Instructions)   OO (Limited Liability Company)

1	Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only) Cormorant Private Healthcare Fund I, LP
2	Check the Appropriate Box if a Member of a Group (See Instructions)
	(a) [ ]
	(b) [x]
3	SEC Use Only
4	Citizenship or Place of Organization.   Delaware
Number of Shares Beneficially Owned by Each Reporting Person With		5 Sole Voting Power   0 shares
		6 Shared Voting Power   114,378 shares   Refer to Item 4 below.
		7 Sole Dispositive Power   0 shares
		8 Shared Dispositive Power   114,378 shares Refer to Item 4 below.
9	Aggregate Amount Beneficially Owned by Each Reporting Person   114,378 shares Refer to Item 4 below.
10	Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions)     [ ] N/A
11	Percent of Class Represented by Amount in Row (9)*   0.70% Refer to Item 4 below.
12	Type of Reporting Person (See Instructions) PN (Partnership)

CUSIP NO.

98420X103

Item 1.

Item 2.

Provide the following information regarding the aggregate number and percentage of the class of securities of the issuer identified in Item 1.

*** Shares reported herein for Cormorant Asset Management, LP represent shares which are beneficially by Cormorant Global Healthcare Master Fund, LP (the “Master Fund”) and Cormorant Private Healthcare Fund I, LP (“Fund I”), as reported herein, and a managed account (the “Account”).  Cormorant Global Healthcare GP, LLC and Cormorant Private Healthcare GP, LLC serve as the general partners of the Master Fund and Fund I, respectively. Cormorant Asset Management, LP serves as the investment manager to the Master Fund, Fund I and the Account.  Bihua Chen serves as the managing member of Cormorant Global Healthcare GP, LLC, Cormorant Private Healthcare GP, LLC and the general partner of Cormorant Asset Management, LP.  Each of the Reporting Persons disclaims beneficial ownership of the shares reported herein except to the extent of its or his pecuniary interest therein.

If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than five percent of the class of securities, check the following [ X ].

Not applicable.

Not applicable.

Not applicable.

Not applicable.

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this Statement is true, complete and correct.

February 14, 2020