(Amendment No. 2) *
Check the appropriate box to designate the
rule pursuant to which this Schedule is filed:
* 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 the disclosures provided in a prior cover page.
The information required in 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 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
|
13G
|
Page 2 of 11 Pages
|
|
1.
|
NAME OF REPORTING PERSONS
I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY)
Deerfield Mgmt, L.P.
|
|
2.
|
CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
|
(a)
☐
(b) ☒
|
|
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
|
|
|
6.
|
SHARED VOTING POWER
906,937 (1)
|
|
|
7.
|
SOLE DISPOSITIVE POWER
0
|
|
|
8.
|
SHARED DISPOSITIVE POWER
906,937 (1)
|
|
|
9.
|
AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
906,937 (1)
|
|
10.
|
CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN
SHARES*
|
☐
|
|
11.
|
PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
5.48%
|
|
12.
|
TYPE OF REPORTING PERSON*
PN
|
__________________
(1) Comprised of (i) an aggregate of 449,437 shares of common
stock and (ii) warrants to purchase an aggregate of 457,500 shares of common stock (subject to any further adjustments that may
be applicable) held by Deerfield Special Situations Fund, L.P. and Deerfield Partners, L.P. Deerfield Mgmt, L.P. is the general
partner of each of Deerfield Special Situations Fund, L.P. and Deerfield Partners, L.P. The provisions of the warrants beneficially
owned by the reporting person restrict the exercise of such securities to the extent that such exercise would cause the number
of shares then beneficially owned by the holder, any affiliate of the holder and any other person or entities with which such
holder’s beneficial ownership of the Issuer’s common stock would be aggregated for purposes of Section 13(d) to exceed
9.99% of the total number of shares of the Issuer then outstanding (the “Ownership Cap”). Accordingly, notwithstanding
the number of shares reported, the reporting person disclaims beneficial ownership of the shares of common stock issuable upon
exercise of such warrants to the extent that upon such exercise the number of shares beneficially owned by all reporting persons
hereunder, in the aggregate, would exceed the Ownership Cap.
|
CUSIP No.
|
98420X103
|
13G
|
Page 3 of 11 Pages
|
|
1.
|
NAME OF REPORTING PERSONS
I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY)
Deerfield Management
Company, L.P.
|
|
2.
|
CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
|
(a)
☐
(b) ☒
|
|
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
|
|
|
6.
|
SHARED VOTING POWER
906,937 (2)
|
|
|
7.
|
SOLE DISPOSITIVE POWER
0
|
|
|
8.
|
SHARED DISPOSITIVE POWER
906,937 (2)
|
|
|
9.
|
AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
906,937 (2)
|
|
10.
|
CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN
SHARES*
|
☐
|
|
11.
|
PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
5.48%
|
|
12.
|
TYPE OF REPORTING PERSON*
PN
|
__________________
(2) Comprised of (i) an aggregate of 449,437 shares of common
stock and (ii) warrants to purchase an aggregate of 457,500 shares of common stock (subject to any further adjustments that may
be applicable) held by Deerfield Special Situations Fund, L.P. and Deerfield Partners, L.P. Deerfield Management Company, L.P.
is the investment advisor of each of Deerfield Special Situations Fund, L.P. and Deerfield Partners, L.P. The provisions of the
warrants beneficially owned by the reporting person restrict the exercise of such securities to the extent that such exercise
would cause the number of shares then beneficially owned by the holder, any affiliate of the holder and any other person or entities
with which such holder’s beneficial ownership of the Issuer’s common stock would be aggregated for purposes of Section
13(d) to exceed 9.99% of the total number of shares of the Issuer then outstanding (the “Ownership Cap”). Accordingly,
notwithstanding the number of shares reported, the reporting person disclaims beneficial ownership of the shares of common stock
issuable upon exercise of such warrants to the extent that upon such exercise the number of shares beneficially owned by all reporting
persons hereunder, in the aggregate, would exceed the Ownership Cap.
|
CUSIP No.
|
98420X103
|
13G
|
Page 4 of 11 Pages
|
|
1.
|
NAME OF REPORTING PERSONS
I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY)
Deerfield Special Situations Fund, L.P.
|
|
2.
|
CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
|
(a)
☐
(b) ☒
|
|
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
|
|
|
6.
|
SHARED VOTING POWER
627,115 (3)
|
|
|
7.
|
SOLE DISPOSITIVE POWER
0
|
|
|
8.
|
SHARED DISPOSITIVE POWER
627,115 (3)
|
|
|
9.
|
AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
627,115 (3)
|
|
10.
|
CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN
SHARES*
|
☐
|
|
11.
|
PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
3.83%
|
|
12.
|
TYPE OF REPORTING PERSON*
PN
|
__________________
(3) Comprised of 344,615 shares of common stock and warrants
to purchase 282,500 shares of common stock (subject to any further adjustments that may be applicable). The provisions of the
warrants beneficially owned by the reporting person restrict the exercise of such securities to the extent that such exercise
would cause the number of shares then beneficially owned by the holder, any affiliate of the holder and any other person or entities
with which such holder’s beneficial ownership of the Issuer’s common stock would be aggregated for purposes of Section
13(d) to exceed 9.99% of the total number of shares of the Issuer then outstanding (the “Ownership Cap”). Accordingly,
notwithstanding the number of shares reported, the reporting person disclaims beneficial ownership of the shares of common stock
issuable upon exercise of such warrants to the extent that upon such exercise the number of shares beneficially owned by all reporting
persons hereunder, in the aggregate, would exceed the Ownership Cap.
|
CUSIP No.
|
98420X103
|
13G
|
Page 5 of 11 Pages
|
|
1.
|
NAME OF REPORTING PERSONS
I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY)
Deerfield Partners, L.P.
|
|
2.
|
CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
|
(a)
☐
(b) ☒
|
|
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
|
|
|
6.
|
SHARED VOTING POWER
279,822 (4)
|
|
|
7.
|
SOLE DISPOSITIVE POWER
0
|
|
|
8.
|
SHARED DISPOSITIVE POWER
279,822 (4)
|
|
|
9.
|
AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
279,822 (4)
|
|
10.
|
CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN
SHARES*
|
☐
|
|
11.
|
PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
1.72%
|
|
12.
|
TYPE OF REPORTING PERSON*
PN
|
__________________
(4) Comprised of 104,822 shares of common stock and warrants
to purchase 175,000 shares of common stock (subject to any further adjustments that may be applicable). The provisions of the
warrants beneficially owned by the reporting person restrict the exercise of such securities to the extent that such exercise
would cause the number of shares then beneficially owned by the holder, any affiliate of the holder and any other person or entities
with which such holder’s beneficial ownership of the Issuer’s common stock would be aggregated for purposes of Section
13(d) to exceed 9.99% of the total number of shares of the Issuer then outstanding (the “Ownership Cap”). Accordingly,
notwithstanding the number of shares reported, the reporting person disclaims beneficial ownership of the shares of common stock
issuable upon exercise of such warrants to the extent that upon such exercise the number of shares beneficially owned by all reporting
persons hereunder, in the aggregate, would exceed the Ownership Cap.
|
CUSIP No.
|
98420X103
|
13G
|
Page 6 of 11 Pages
|
|
1.
|
NAME OF REPORTING PERSONS
I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY)
James E. Flynn
|
|
2.
|
CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
|
(a)
☐
(b) ☒
|
|
3.
|
SEC USE ONLY
|
|
4.
|
CITIZENSHIP OR PLACE OF ORGANIZATION
United States
|
|
NUMBER OF
SHARES
BENEFICIALLY
OWNED BY
EACH
REPORTING
PERSON
WITH
|
5.
|
SOLE VOTING POWER
0
|
|
|
6.
|
SHARED VOTING POWER
906,937 (5)
|
|
|
7.
|
SOLE DISPOSITIVE POWER
0
|
|
|
8.
|
SHARED DISPOSITIVE POWER
906,937 (5)
|
|
|
9.
|
AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
906,937 (5)
|
|
10.
|
CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN
SHARES*
|
☐
|
|
11.
|
PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
5.48%
|
|
12.
|
TYPE OF REPORTING PERSON*
IN
|
__________________
(5) Comprised of (i) an aggregate of 449,437 shares of common
stock and (ii) warrants to purchase an aggregate of 457,500 shares of common stock (subject to any further adjustments that may
be applicable) held by Deerfield Special Situations Fund, L.P. and Deerfield Partners, L.P. The provisions of the warrants beneficially
owned by the reporting person restrict the exercise of such securities to the extent that such exercise would cause the number
of shares then beneficially owned by the holder, any affiliate of the holder and any other person or entities with which such
holder’s beneficial ownership of the Issuer’s common stock would be aggregated for purposes of Section 13(d) to exceed
9.99% of the total number of shares of the Issuer then outstanding (the “Ownership Cap”). Accordingly, notwithstanding
the number of shares reported, the reporting person disclaims beneficial ownership of the shares of common stock issuable upon
exercise of such warrants to the extent that upon such exercise the number of shares beneficially owned by all reporting persons
hereunder, in the aggregate, would exceed the Ownership Cap.
|
CUSIP No.
|
98420X103
|
13G
|
Page 7 of 11 Pages
|
|
Item 1(a).
|
Name of Issuer:
|
|
|
|
|
|
X4
Pharmaceuticals, Inc.
|
|
|
|
|
Item 1(b).
|
Address of Issuer's Principal Executive Offices:
|
|
|
|
|
|
955 Massachusetts Avenue, 4th Floor
Cambridge, Massachusetts 02139
|
|
|
|
|
Item 2(a).
|
Name of Person Filing:
|
|
|
|
|
|
James
E. Flynn, Deerfield Mgmt, L.P., Deerfield Special Situations Fund, L.P., Deerfield Partners, L.P. and Deerfield Management Company,
L.P.
|
|
|
|
|
Item 2(b).
|
Address of Principal Business Office, or if None, Residence:
|
|
|
|
|
|
James
E. Flynn, Deerfield Mgmt, L.P., Deerfield Special Situations Fund, L.P., Deerfield Partners, L.P. and Deerfield Management Company,
L.P., 780 Third Avenue, 37th Floor, New York, NY 10017
|
|
|
|
|
Item 2(c).
|
Citizenship:
|
|
|
|
|
|
Deerfield Mgmt, L.P., Deerfield Management Company,
L.P., Deerfield Special Situations Fund, L.P. and Deerfield Partners, L.P. - Delaware limited partnerships;
James E. Flynn – United States citizen
|
|
|
|
|
Item 2(d).
|
Title of Class of Securities:
|
|
|
|
|
|
Common
Stock, par value $0.001 per share
|
|
|
|
|
Item 2(e).
|
CUSIP Number:
|
|
|
|
|
|
98420X103
|
|
|
|
|
|
Item 3.
|
If This Statement is Filed Pursuant to
Rule 13d-1(b), or 13d-2(b) or (c), Check Whether the Person Filing is a:
|
|
|
|
|
(a)
|
☐
|
Broker or dealer registered under Section 15 of the
Exchange Act.
|
|
|
|
|
|
(b)
|
☐
|
Bank as defined in Section 3(a)(6) of the Exchange Act.
|
|
|
|
|
|
(c)
|
☐
|
Insurance company as defined in Section 3(a)(19) of
the Exchange Act.
|
|
|
|
|
|
(d)
|
☐
|
Investment company registered under Section 8 of the
Investment Company Act.
|
|
|
|
|
|
(e)
|
☐
|
An investment adviser in accordance with Rule 13d-1(b)(1)(ii)(E);
|
|
|
|
|
|
(f)
|
☐
|
An employee benefit plan or endowment fund in accordance
with Rule 13d-1(b)(1)(ii)(F);
|
|
|
|
|
|
(g)
|
☐
|
A parent holding company or control person in accordance
with Rule 13d-1(b)(1)(ii)(G);
|
|
|
|
|
|
(h)
|
☐
|
A savings association as defined in Section 3(b) of
the Federal Deposit Insurance Act;
|
|
|
|
|
|
(i)
|
☐
|
A church plan that is excluded from the definition
of an investment company under Section 3(c)(14) of the Investment Company Act;
|
|
CUSIP No.
|
98420X103
|
13G
|
Page 8 of 11 Pages
|
|
|
|
|
|
(j)
|
☐
|
A non-U.S. institution in accordance with Rule 13d-1(b)(1)(ii)(J);
|
|
|
|
|
|
(k)
|
☐
|
Group, in accordance with Rule 13d-1(b)(1)(ii)(K).
|
If filing as a non-U.S. institution in accordance
with Rule 13d-1(b)(1)(ii)(J), please specify the type of institution: _________________
|
Item 4.
|
Ownership.
|
|
|
|
|
|
|
Provide the following information regarding the aggregate number and percentage of the class of securities of the issuer identified in Item 1.
|
|
|
|
|
|
|
(a)
|
Amount beneficially owned**:
|
|
|
|
|
|
|
|
|
Deerfield Mgmt, L.P. - 906,937 shares
Deerfield Management Company, L.P. - 906,937 shares
Deerfield Special Situations Fund, L.P. - 627,115
shares
Deerfield Partners, L.P. – 279,822 shares
James E. Flynn – 906,937 shares
|
|
|
|
|
|
|
(b)
|
Percent of class**:
|
|
|
|
|
|
|
|
|
Deerfield Mgmt, L.P. - 5.48%
Deerfield Management Company, L.P. - 5.48%
Deerfield Special Situations Fund, L.P. – 3.83%
Deerfield Partners, L.P. – 1.72%
James E. Flynn – 5.48%
|
|
|
|
|
|
|
(c)
|
Number of shares as to which such person has**:
|
|
|
|
|
|
|
|
|
(i)
|
Sole power to vote or to direct the vote:
|
All Reporting Persons - 0
|
|
|
|
|
|
|
|
(ii)
|
Shared power to vote or to direct the vote:
|
Deerfield Mgmt, L.P. - 906,937 shares
Deerfield Management Company, L.P. - 906,937 shares
Deerfield Special Situations Fund, L.P. - 627,115
shares
Deerfield Partners, L.P. – 279,822 shares
James E. Flynn – 906,937 shares
|
|
|
|
|
|
|
|
(iii)
|
Sole power to dispose or to direct the disposition of:
|
All Reporting Persons - 0
|
|
|
|
|
|
|
|
(iv)
|
Shared power to dispose or to direct the disposition
of:
|
Deerfield Mgmt, L.P. - 906,937 shares
Deerfield Management Company, L.P. - 906,937 shares
Deerfield Special Situations Fund, L.P. - 627,115
shares
Deerfield Partners, L.P. – 279,822 shares
James E. Flynn – 906,937 shares
|
**See footnotes on cover pages which are incorporated by reference
herein.
|
CUSIP No.
|
98420X103
|
13G
|
Page 9 of 11 Pages
|
|
Item 5.
|
Ownership of Five Percent or Less of a Class.
|
|
|
|
|
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 ☐.
|
|
|
|
|
|
|
|
|
|
|
Item 6.
|
Ownership of More Than Five Percent on Behalf of Another Person.
|
|
|
|
|
If any other person is known to have the right to receive or
the power to direct the receipt of dividends from, or the proceeds from the sale of, such securities, a statement to that effect
should be included in response to this item and, if such interest relates to more than five percent of the class, such person should
be identified. A listing of the shareholders of an investment company registered under the Investment Company Act of 1940 or the
beneficiaries of employee benefit plan, pension fund or endowment fund is not required.
|
|
|
|
|
|
N/A
|
|
|
|
|
Item 7.
|
Identification and Classification of the Subsidiary
Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
|
|
|
|
|
If a parent holding company or Control person has filed this
schedule, pursuant to Rule 13d-1(b)(1)(ii)(G), so indicate under Item 3(g) and attach an exhibit stating the identity and the Item
3 classification of the relevant subsidiary. If a parent holding company or control person has filed this schedule pursuant to
Rule 13d-1(c) or Rule 13d-1(d), attach an exhibit stating the identification of the relevant subsidiary.
|
|
|
|
|
|
N/A
|
|
CUSIP No.
|
98420X103
|
13G
|
Page 10 of 11 Pages
|
|
|
|
|
Item 8.
|
Identification and Classification of Members of the Group.
|
|
|
|
|
If a group has filed this schedule pursuant to ss.240.13d-1(b)(1)(ii)(J),
so indicate under Item 3(j) and attach an exhibit stating the identity and Item 3 classification of each member of the group. If
a group has filed this schedule pursuant to ss.240.13d-1(c) or ss.240.13d-1(d), attach an exhibit stating the identity of each
member of the group.
|
|
|
|
|
|
See Exhibit B
|
|
|
|
|
Item 9.
|
Notice of Dissolution of Group.
|
|
|
|
|
Notice of dissolution of a group may be furnished as an exhibit
stating the date of the dissolution and that all further filings with respect to transactions in the security reported on will
be filed, if required, by members of the group, in their individual capacity. See Item 5.
|
|
|
|
|
|
N/A
|
|
|
|
|
Item 10.
|
Certifications.
|
|
|
|
|
"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, other than activities solely in connection with a nomination under §240.14a–11."
|
|
CUSIP No.
|
98420X103
|
13G
|
Page 11 of 11 Pages
|
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.
DEERFIELD MGMT, L.P.
By: J.E. Flynn Capital, LLC, General Partner
By: /s/ Jonathan Isler
Jonathan Isler, Attorney-In-Fact
DEERFIELD MANAGEMENT COMPANY, L.P.
By: Flynn Management LLC, General Partner
By: /s/ Jonathan Isler
Jonathan Isler, Attorney-In-Fact
DEERFIELD SPECIAL SITUATIONS FUND, L.P.
By: Deerfield Mgmt, L.P., General Partner
By: J.E. Flynn Capital, LLC, General Partner
By: /s/ Jonathan Isler
Jonathan Isler, Attorney-In-Fact
DEERFIELD PARTNERS, L.P.
By: Deerfield Mgmt, L.P., General Partner
By: J.E. Flynn Capital, LLC, General Partner
By: /s/ Jonathan Isler
Jonathan Isler, Attorney-In-Fact
JAMES E. FLYNN
/s/ Jonathan Isler
Jonathan Isler, Attorney-In-Fact
Date: February 13, 2020
Exhibit List
Exhibit A. Joint Filing Agreement.
Exhibit B. Item 8 Statement.
Exhibit C. Power of Attorney (1).
(1) Power of Attorney previously filed as Exhibit 24 to a Form
3 with regard to Proteon Therapeutics, Inc. filed with the Securities and Exchange Commission on August 4, 2017 by Deerfield Special
Situations Fund, L.P., Deerfield Partners, L.P., Deerfield International Master Fund, L.P., Deerfield Private Design Fund III,
L.P., Deerfield Private Design Fund IV, L.P., Deerfield Mgmt, L.P., Deerfield Mgmt III, L.P., Deerfield Mgmt IV, L.P., Deerfield
Management Company, L.P., and James E. Flynn.
Exhibit A
Joint Filing Agreement
The undersigned agree that this Schedule 13G, and all amendments
thereto, relating to the Common Stock of X4 Pharmaceuticals, Inc. shall be filed on behalf of the undersigned.
DEERFIELD MGMT, L.P.
By: J.E. Flynn Capital, LLC, General Partner
By: /s/ Jonathan Isler
Jonathan Isler, Attorney-In-Fact
DEERFIELD MANAGEMENT COMPANY, L.P.
By: Flynn Management LLC, General Partner
By: /s/ Jonathan Isler
Jonathan Isler, Attorney-In-Fact
DEERFIELD SPECIAL SITUATIONS FUND, L.P.
By: Deerfield Mgmt, L.P., General Partner
By: J.E. Flynn Capital, LLC, General Partner
By: /s/ Jonathan Isler
Jonathan Isler, Attorney-In-Fact
DEERFIELD PARTNERS, L.P.
By: Deerfield Mgmt, L.P., General Partner
By: J.E. Flynn Capital, LLC, General Partner
By: /s/ Jonathan Isler
Jonathan Isler, Attorney-In-Fact
JAMES E. FLYNN
/s/ Jonathan Isler
Jonathan Isler, Attorney-In-Fact
Exhibit B
Due to the relationships between them,
the reporting persons hereunder may be deemed to constitute a “group” with one another for purposes of Section 13(d)(3)
of the Securities Exchange Act of 1934.
