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 	  
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X	
	
	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*
Atlas Venture Fund VII L P	

(Last)	(First)	(Middle)	
25 FIRST STREET, SUITE 303	

(Street) 
CAMBRIDGE	MA	02141	

(City)	(State)	(Zip)	
	2. Issuer Name and Ticker or Trading Symbol 
ZAFGEN, INC. [ ZFGN ] 	5. Relationship of Reporting Person(s) to Issuer 
(Check all applicable) 
	Director	X	10% Owner	
	Officer (give title below)		Other (specify below)	

	3. Date of Earliest Transaction (Month/Day/Year)
06/29/2018 		
	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	06/29/2018		J(1) 		1,126,546	D	$0(1) 	3,506,184	D(3) 		
Common Stock	06/29/2018		J(2) 		234,321	D	$0(1) 	11	D(4) 		
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*
Atlas Venture Fund VII L P	

(Last)	(First)	(Middle)	
25 FIRST STREET, SUITE 303	

(Street) 
CAMBRIDGE	MA	02141	

(City)	(State)	(Zip)	
	
1. Name and Address of Reporting Person*
Atlas Venture Associates VII, L.P.	

(Last)	(First)	(Middle)	
25 FIRST STREET, SUITE 303	

(Street) 
CAMBRIDGE	MA	02141	

(City)	(State)	(Zip)	
	
1. Name and Address of Reporting Person*
Atlas Venture Associates VII, Inc.	

(Last)	(First)	(Middle)	
25 FIRST STREET, SUITE 303	

(Street) 
CAMBRIDGE	MA	02141	

(City)	(State)	(Zip)	
	
Explanation of Responses:	
1. On June 29, 2018, Atlas Venture Fund VII LP ("Atlas Venture VII") distributed, for no consideration, 1,126,546 shares of the Issuer's Common Stock, pro-rata, to its partners, including its limited partners and its general partner, in accordance with the exemptions afforded by Rule 16a-9 and Rule 16a-13 of the Securities Exchange Act of 1934, as amended. The distribution was effected pursuant to a Rule 10b5-1 plan adopted by Atlas Venture VII on December 22, 2017.	
2. On June 29, 2018, Atlas Venture Associates VII LP ("AVA VII LP"), the general partner of Atlas Venture VII distributed, for no consideration, 234,421 shares of the Issuer's Common Stock, pro-rata, to its partners, including its limited partners and its general partner, in accordance with the exemptions afforded by Rule 16a-9 and Rule 16a-13 of the Securities Exchange Act of 1934, as amended. The distribution was effected pursuant to a Rule 10b5-1 plan adopted by AVA VII on December 22, 2017.	
3. These shares are held directly by Atlas Venture VII. The general partner of Atlas Venture VII is AVA VII LP, and the general partner of AVA VII LP is Atlas Venture Associates VII, Inc. ("AVA VII Inc."). AVA VII LP and AVA VII Inc. disclaim Section 16 beneficial ownership of such shares, except to the extent of a pecuniary interest, if any, therein. This report shall not be deemed an admission that the reporting persons are the beneficial owners of such securities for the purposes of Section 16 or for any other purpose.	
4. These shares are held directly by AVA VII LP. The general partner of AVA VII LP is AVA VII Inc. AVA VII Inc. disclaims Section 16 beneficial ownership of such shares, except to the extent of a pecuniary interest, if any, therein. This report shall not be deemed an admission that the reporting person is the beneficial owner of such securities for the purposes of Section 16 or for any other purpose.	
	By: Atlas Venture Fund VII LP, By: Atlas Venture Associates VII, L.P., its general partner, By: Atlas Venture Associates VII, Inc., its general partner, /s/ Frank Castellucci, Secretary	07/03/2018	
	By: Atlas Venture Associates VII, L.P., By: Atlas Venture Associates VII, Inc., its general partner, /s/ Frank Castellucci, Secretary	07/03/2018	
	By: Atlas Venture Associates VII, Inc., /s/ Frank Castellucci, Secretary	07/03/2018	
	** 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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