X0306 4 2015-07-13 0 0001374690 ZAFGEN, INC. ZFGN 0001291895 Barrett Peter C/O ATLAS VENTURE FUND VII, L.P., 25 FIRST STREET, SUITE 303 CAMBRIDGE MA 02141 1 0 1 0 Stock Option (Right to Buy) 37.15 2015-07-13 4 A 0 12000 0.00 A 2025-07-13 Common Stock 12000 12000 D These options were issued under the nonemployee director compensation policy and will vest in full upon the earlier of the first anniversary of the date of the 2015 annual meeting of stockholders or the date of the 2016 annual meeting of stockholders. /s/ Laurie Burlingame (Attorney-In-Fact) 2015-07-15