Statement of Changes in Beneficial Ownership (4)

FORM 4 [ ] Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES
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Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

1. Name and Address of Reporting Person ^* Levy Noah G.	2. Issuer Name and Ticker or Trading Symbol MERRIMACK PHARMACEUTICALS INC [ MACK ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) __X__ Director _____ 10% Owner _____ Officer (give title below) __X__ Other (specify below) See remarks
(Last) (First) (Middle) 60 EAST 42ND STREET, 9TH FLOOR	3. Date of Earliest Transaction (MM/DD/YYYY) 12/1/2020
(Street) NEW YORK, NY 10165 (City) (State) (Zip)	4. If Amendment, Date Original Filed (MM/DD/YYYY)	6. Individual or Joint/Group Filing (Check Applicable Line) ___ Form filed by One Reporting Person _ X _ Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security (Instr. 3)	2. Trans. Date	2A. Deemed Execution Date, if any	3. Trans. Code (Instr. 8)		4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
1.Title of Security (Instr. 3)	2. Trans. Date	2A. Deemed Execution Date, if any	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	12/1/2020		P		17359	A	$3.9991 ⁽¹⁾	896642	I	See footnote ⁽²⁾
Common Stock	12/1/2020		P		12417	A	$3.9991 ⁽³⁾	652241	I	See footnote ⁽⁴⁾

*Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)*
1. Title of Derivate Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Trans. Date	3A. Deemed Execution Date, if any	4. Trans. Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
1. Title of Derivate Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Trans. Date	3A. Deemed Execution Date, if any	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)			11. Nature of Indirect Beneficial Ownership (Instr. 4)

Explanation of Responses:
(1)	The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $3.955 to $4.000, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (1) to this Form 4.
(2)	The shares are directly held by NP. The general partner of the Funds is NCP. The general partner of NCP is Ledo. The investment manager to the Funds is Newtyn Management. The managing member of Newtyn Management and Ledo and the portfolio manager to the Funds is Mr. Levy. Each of Newtyn Management, Ledo, NCP and Mr. Levy disclaims beneficial ownership of the shares except to the extent of its or his pecuniary interest therein, if any, and this report shall not be deemed an admission that it or he is the beneficial owner of such shares.
(3)	The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $3.955 to $4.000, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (3) to this Form 4.
(4)	The shares are directly held Newtyn TE. The general partner of the Funds is NCP. The general partner of NCP is Ledo. The investment manager to the Funds is Newtyn Management. The managing member of Newtyn Management and Ledo and the portfolio manager to the Funds is Mr. Levy. Each of Newtyn Management, Ledo, NCP and Mr. Levy disclaims beneficial ownership of the shares except to the extent of its or his pecuniary interest therein, if any, and this report shall not be deemed an admission that it or he is the beneficial owner of such shares.

Remarks:
As a result of an agreement among the persons listed below to vote their respective shares of Common Stock jointly, such persons have formed a "group" under Section 13(d)(1) of the Exchange Act. In addition to Mr. Levy, Newtyn Management, LLC ("Newtyn Management"), Newtyn Partners, LP ("NP"), Newtyn TE Partners, LP ("Newtyn TE" and together with NP, the "Funds"), Newtyn Capital Partners, LP ("NCP") and Ledo Capital, LLC ("Ledo") (collectively, the "Newtyn Parties"), the members of this group are Eric D. Andersen, Western Standard, LLC, Western Standard Partners, L.P. and Western Standard Partners QP, L.P. (the "Western Standard Parties" and collectively with the Newtyn Parties, the "13D Group"). As a member of the 13D Group, each Newtyn Party would be deemed to beneficially own the aggregate amount of the Common Stock that each of the 13D Group members beneficially owns, in which case it or he would be deemed to beneficially own 2,737,728 shares of Common Stock. However, none of the Newtyn Parties have the ability to direct the acquisition or disposition or, except through the Cooperation Agreement, voting of the securities held by Western Standard Parties, and none of the Western Standard Parties have the ability to direct the acquisition or disposition or, except through the Cooperation Agreement, voting of the securities held by the Newtyn Parties. As members of the 13D Group, the combined holdings of the Newtyn Parties and the Western Standard Parties would result in each Newtyn Party having voting power equivalent to a combined beneficial ownership of 20.5% of the Issuer's outstanding Common Stock for voting purposes. Each Newtyn Party disclaims beneficial ownership of the shares beneficially owned by the 13D Group except to the extent of its or his pecuniary interest therein, if any, and this report shall not be deemed an admission that it or he is the beneficial owner of such shares.

Reporting Owners
Reporting Owner Name / Address	Relationships
Reporting Owner Name / Address	Director	10% Owner	Officer	Other
Levy Noah G. 60 EAST 42ND STREET, 9TH FLOOR NEW YORK, NY 10165	X			See remarks
Newtyn Management, LLC 60 EAST 42ND STREET, 9TH FLOOR NEW YORK, NY 10165				See Remarks
NEWTYN PARTNERS, LP 60 EAST 42ND STREET, 9TH FLOOR NEW YORK, NY 10165				See Remarks
NEWTYN TE PARTNERS, LP 60 EAST 42ND STREET, 9TH FLOOR NEW YORK, NY 10165				See Remarks
Newtyn Capital Partners, LP 60 EAST 42ND STREET, 9TH FLOOR NEW YORK, NY 10165				See Remarks
Ledo Capital, LLC 60 EAST 42ND STREET, 9TH FLOOR NEW YORK, NY 10165				See Remarks

Signatures
/s/ Noah G. Levy		12/3/2020
^**Signature of Reporting Person		Date
Newtyn Management, LLC; /s/ Noah G. Levy, Managing Member		12/3/2020
^**Signature of Reporting Person		Date
Newtyn Partners, LP; By: Newtyn Management, LLC, Investment Manager; /s/ Noah G. Levy, Managing Member		12/3/2020
^**Signature of Reporting Person		Date
Newtyn TE Partners, LP; By: Newtyn Management, LLC, Investment Manager; /s/ Noah G. Levy, Managing Member		12/3/2020
^**Signature of Reporting Person		Date
Newtyn Capital Partners, LP; By: Ledo Capital, LLC, General Partner; /s/ Noah G. Levy, Managing Member		12/3/2020
^**Signature of Reporting Person		Date
Ledo Capital, LLC; /s/ Noah G. Levy, Managing Member		12/3/2020
^**Signature of Reporting Person		Date