SEC Form 4

FORM 4		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* JFL Capital Management, LLC (Last) (First) (Middle) 2110 RANCH ROAD 620 S 341732 (Street) LAKEWAY TX 78734 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol MERRIMACK PHARMACEUTICALS INC [ MACK ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director X 10% Owner Officer (give title below) X Other (specify below) See Explanation of Responses
	3. Date of Earliest Transaction (Month/Day/Year) 06/28/2019
	4. If Amendment, Date of Original Filed (Month/Day/Year)	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. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction 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)
			Code	V	Amount	(A) or (D)	Price
Common Stock(1)	06/28/2019		P		9,662	A	$5.945	499,194	I	By: JFL Partners Fund LP(2)
Common Stock(1)	06/28/2019		P		13,902	A	$5.945	723,910	I	By: Managed Account of JFL Capital Management LLC(3)
Common Stock(1)	07/01/2019		P		3,934	A	$6.0029(4)	503,128	I	By: JFL Partners Fund LP(2)
Common Stock(1)	07/01/2019		P		5,659	A	$6.0029(4)	729,569	I	By: Managed Account of JFL Capital Management LLC(3)
Common Stock(1)	07/02/2019		P		7,024	A	$5.848(5)	510,152	I	By: JFL Partners Fund LP(2)
Common Stock(1)	07/02/2019		P		10,107	A	$5.848(5)	739,676	I	By: Managed Account of JFL Capital Management LLC(3)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction 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 (Month/Day/Year)		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: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

1. Name and Address of Reporting Person* JFL Capital Management, LLC (Last) (First) (Middle) 2110 RANCH ROAD 620 S 341732 (Street) LAKEWAY TX 78734 (City) (State) (Zip)

1. Name and Address of Reporting Person* JFL Capital Management LP (Last) (First) (Middle) 2110 RANCH ROAD 620 S, #341732 (Street) LAKEWAY TX 78734 (City) (State) (Zip)

1. Name and Address of Reporting Person* JFL Capital Holdings LLC (Last) (First) (Middle) 2110 RANCH ROAD 620 S, #341732 (Street) LAKEWAY TX 78734 (City) (State) (Zip)

1. Name and Address of Reporting Person* JFL Partners Fund LP (Last) (First) (Middle) 2110 RANCH ROAD 620S #341732 (Street) LAKEWAY TX 78734 (City) (State) (Zip)

1. Name and Address of Reporting Person* Lawler Joseph F. (Last) (First) (Middle) 2110 RANCH ROAD 620 S, #341732 (Street) LAKEWAY TX 78734 (City) (State) (Zip)

Explanation of Responses:

1. This Form 4 is filed jointly by JFL Partners Fund LP ("JFL Partners"), JFL Capital Management LP ("JFL GP"), JFL Capital Holdings LLC ("JFL Holdings"), JFL Captal Management LLC ("JFL Capital Management") and Joseph F. Lawler (collectively, the "Reporting Persons"). Each of the Reporting Persons may be deemed to be a member of a Section 13(d) group that collectively beneficially owns more than 10% of the Issuer's outstanding shares of Common Stock. Each of the Reporting Persons disclaims beneficial ownership of the securities of the Issuer owned directly by other members of the Section 13(d) group and this report shall not be deemed an admission that the Reporting Persons are the beneficial owners of such securities for purposes of Section 16 or for any other purpose. Further, each of the Reporting Persons expressly disclaims beneficial ownership of the securities reported herein except to the extent of his or its pecuniary interest therein.

2. Securities owned directly by JFL Partners. As the general partner of JFL Partners, JFL GP may be deemed to beneficially own the securities owned directly by JFL Partners. As the general parter of JFL GP, JFL Holdings may be deemed to beneficially own the securities owned directly by JFL Partners. JFL Capital Management, as the investment manager of JFL Partners, may be deemed to beneficially own the securities owned directly by JFL Partners. Dr. Lawler, as the managing member of both JFL Holdings and JFL Capital Management, may be deemed to beneficially own the securities owned directly by JFL Partners.

3. Securities held in an account separately managed by JFL Capital Management (the "JFL Managed Account"). JFL Capital Management, as the investment manager of the JFL Managed Account, may be deemed to beneficially own the securities held in the JFL Managed Account. Dr. Lawler, as the managing member of JFL Capital Management, may be deemed to beneficially own the securities held in the JFL Managed Account.

4. The reported price in Column 4 is a weighted average price. These shares of Common Stock were purchased in multiple transactions at prices ranging from $5.827 to $6.090, excluding commissions. The Reporting Persons undertake 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 of Common Stock purchased at each separate price within the range set forth in this footnote.

5. The reported price in Column 4 is a weighted average price. These shares of Common Stock were purchased in multiple transactions at prices ranging from $5.781 to $5.950, excluding commissions. The Reporting Persons undertake 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 of Common Stock purchased at each separate price within the range set forth in this footnote.

	JFL Capital Management LLC; By: /s/ Joseph F. Lawler, Managing Member	07/02/2019
	JFL Capital Management LP; By: JFL Capital Holdings LLC; By; /s/ Joseph F. Lawler, Managing Member	07/02/2019
	JFL Capital Holdings LLC; By: /s/ Joseph F. Lawler, Managing Member	07/02/2019
	JFL Partners Fund LP; By: JFL Capital Management LP; By: JFL Capital Holdings LLC; By: /s/ Joseph F. Lawler, Managing Member	07/02/2019
	/s/ Joseph F. Lawler	07/02/2019
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
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