X4 Pharmaceuticals : SC 13D/A

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 1)*

X4 Pharmaceuticals, Inc.

(Name of Issuer)

Common Stock, $0.001 par value

(Title of Class of Securities)

98420X103

(CUSIP Number)

Louis S. Citron, Esq.

New Enterprise Associates

1954 Greenspring Drive, Suite 600, Timonium, MD 21093

[phone]

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

March 13, 2019

(Date of Event which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§240.13d-1(e),240.13d-1(f) or 240.13d-1(g), check the following box. ☐

Note: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See §240.13d-7 for other parties to whom copies are to be sent.

*The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

CUSIP No. 98420X103

13D

Page 2 of 9 Pages

Schedule 13D

Item 1. Security and Issuer.

This Amendment No. 1 ("Amendment No. 1") to Schedule 13D amends and restates the statement on Schedule 13D originally filed on November 29,

2017 relating to the common shares, $0.001 par value (the "Common Stock"), of X4 Pharmaceuticals, Inc. (f/k/a Arsanis, Inc.) (the "Issuer") having its principal executive office at 955 Massachusetts Avenue, 4th Floor, Cambridge, Massachusetts 02139.

Certain terms used but not defined in this Amendment No. 1 have the meanings assigned thereto in the Schedule 13D. Except as specifically provided herein, this Amendment No. 1 does not modify any of the information previously reported on the Schedule 13D.

Item 2. Identity and Background.

This statement is being filed by:

(a) New Enterprise Associates 16, L.P. ("NEA 16"), NEA Partners 16, L.P. ("NEA Partners 16"), which is the sole general partner of NEA 16; and NEA 16 GP, LLC ("NEA 16 LLC" and, together with NEA Partners 16, the "Control Entities"), which is the sole general partner of NEA Partners 16; and

1. Peter J. Barris ("Barris"), Forest Baskett ("Baskett"), Anthony A. Florence, Jr. ("Florence"), Mohamad H. Makhzoumi ("Makhzoumi"), Joshua Makower ("Makower"), David M. Mott ("Mott"), Scott D. Sandell ("Sandell") and Peter W. Sonsini ("Sonsini") (together, the "Managers"), Chetan Puttagunta ("Puttagunta"), Jon M. Sakoda ("Sakoda") and Ravi Viswanathan ("Viswanathan"). The Managers are the managers of NEA 16 LLC.

The persons named in this Item 2 are referred to individually herein as a "Reporting Person" and collectively as the "Reporting Persons."

The address of the principal business office of NEA 16 and each Control Entity is New Enterprise Associates, 1954 Greenspring Drive, Suite 600, Timonium, MD 21093. The address of the principal business office of each of Barris and Mott is New Enterprise Associates, 5425 Wisconsin Avenue, Suite 800, Chevy Chase, MD 20815. The address of the principal business office of Baskett, Makhzoumi, Makower, Sandell and Sonsini is New Enterprise Associates, 2855 Sand Hill Road, Menlo Park, California 94025. The address of the principal business office of Florence is New Enterprise Associates, 104 5th Avenue, 19th Floor, New York, NY 10001.

The principal business of NEA 16 is to invest in and assist growth-oriented businesses located principally in the United States. The principal business of NEA Partners 16 is to act as the sole general partner of NEA 16. The principal business of NEA 16 LLC is to act as the sole general partner of NEA Partners 16. The principal business of each of the Managers is to manage the Control Entities, NEA 16 and a number of affiliated partnerships with similar businesses.

During the five years prior to the date hereof, none of the Reporting Persons has been convicted in a criminal proceeding or has been a party to a civil proceeding ending in a judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws or finding any violation with respect to such laws.

NEA 16 LLC is a limited liability company organized under the laws of the State of Delaware. NEA 16 and NEA Partners 16 are limited partnerships organized under the laws of the State of Delaware. Each of the Managers is a United States citizen.

CUSIP No. 98420X103

13D

Page 3 of 9 Pages

Item 4. Purpose of Transaction.

Not applicable.

Item 5. Interest in Securities of the Issuer.

Each of the Reporting Persons has ceased to own beneficially five percent or more of the Issuer's Common Stock

Item 7. Material to be Filed as Exhibits.

Exhibit 1 - Agreement regarding filing of joint Schedule 13D.

Exhibit 2 - Power of Attorney regarding filings under the Securities Exchange Act of 1934, as amended.

CUSIP No. 98420X103

13D

Page 4 of 9 Pages

SIGNATURE

After reasonable inquiry and to the best of its knowledge and belief, each of the undersigned certifies that the information set forth in this statement is true, complete and correct.

EXECUTED this 28th day of May, 2019.

NEW ENTERPRISE ASSOCIATES 16, L.P.

By:	NEA PARTNERS 16, L.P.
	General Partner
	By:	NEA 16 GP, LLC
		General Partner
		By:		*

	Scott D. Sandell
	Chief Executive Officer
NEA PARTNERS 16, L.P.
By:	NEA 16 GP, LLC
	General Partner

By:*

Scott D. Sandell

Chief Executive Officer

NEA 16 GP, LLC

By:*

Scott D. Sandell

Chief Executive Officer

*

Peter J. Barris

*

Forest Baskett

CUSIP No. 98420X103

13D

Page 5 of 9 Pages

*

Anthony A. Florence, Jr.

*

Mohamad H. Makhzoumi

*

Joshua Makower

*

David M. Mott

*

Scott D. Sandell

*

Peter W. Sonsini

*/s/ Sasha O. Keough Sasha O. Keough As attorney-in-fact

This Amendment No. 1 to Schedule 13D was executed by Sasha O. Keough on behalf of the individuals listed above pursuant to a Power of Attorney a copy of which is attached as Exhibit 2.