Sec Form 3 Filing - Ratcliffe Liam @ Unum Therapeutics, Inc. - 2018-03-28

FORM 3 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 Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person Ratcliffe Liam 2. Issuer Name and Ticker or Trading Symbol Unum Therapeutics, Inc. [ UMRX] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O UNUM THERAPEUTICS INC., 200 CAMBRIDGE PARK DRIVE, SUITE 3100 3. Date of Earliest Transaction (MM/DD/YY) 03/28/2018 (Street) CAMBRIDGE, MA02410 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 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

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 (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 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 (MM/DD/YY) 7. Title and Amount of Underlying Securities (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) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Series B Preferred Stock ( 1 ) ( 1 ) ( 1 ) Common Stock 622,772 I See Footnote ( 2 ) ( 3 ) Series B Preferred Stock ( 1 ) ( 1 ) ( 1 ) Common Stock 622,773 I See Footnote ( 4 ) ( 5 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Ratcliffe Liam C/O UNUM THERAPEUTICS INC. 200 CAMBRIDGE PARK DRIVE, SUITE 3100 CAMBRIDGE, MA02410 X Signatures /s/ Amoli Pandya, Attorney-in-Fact 03/28/2018 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Each share is convertible on a 1.5701314513884-for-1 basis into Common Stock at any time at the election of the Reporting Person and will automatically convert upon the closing of the Issuer's initial public offering into the number of shares of the Issuer's Common Stock shown in column 3 without payment or further consideration. ( 2 )The shares are held directly by New Leaf Biopharma Opportunities I, L.P. ("Biopharma I"). New Leaf BPO Associates I, L.P. ("NLBA I") is the sole general partner of Biopharma I. New Leaf Venture Management III, L.L.C. ("NLV Management III") is the sole general partner of NLBA I. New Leaf Venture Partners, L.L.C. ("NLVP") is the investment adviser of Biopharma I. Each of NLBA I and NLV Management III disclaim beneficial ownership of these securities and this report shall not be deemed an admission that NLBA I or NLV Management III are beneficial owners of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein. Each of the Reporting Person, Ronald M. Hunt and Vijay K. Lathi (each a "Member" and collectively, the "Members") is a member of NLV Management III and may be deemed to have shared voting and dispositive power of these securities. Continued in Footnote 3 ( 3 )Continued from Footnote 2: Each of the Members disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any of them is the beneficial owner of such securities for purposes of Section 16 of any other purpose, except to the extent of their respective pecuniary interests therein. ( 4 )The shares are held directly by New Leaf Ventures III, L.P. ("NLV III").New Leaf Venture Associates III, L.P. ("NLV Associates III") is the sole general partner of NLV III. NLV Management III is the sole general partner of NLV Associates III. NLVP is the investment adviser of NLV III.Each of NLV Associates and NLV Management III disclaim beneficial ownership of these securities and this report shall not be deemed an admission that NLBA I or NLV Management III are beneficial owners of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein. Each of the Members may be deemed to have shared voting and dispositive power of these securities. Continued in Footnote 5 ( 5 )Continued from Footnote 4: Each of the Members disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any of them is the beneficial owner of such securities for purposes of Section 16 of any other purpose, except to the extent of their respective pecuniary interests therein.

Remarks: Exhibit 24 - Power of Attorney (attached)

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).

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