X0306 4 2019-04-02 0 0001374690 ZAFGEN, INC. ZFGN 0001769608 Singhal Priya C/O ZAFGEN, INC., 4TH FLOOR 175 PORTLAND STREET BOSTON MA 02114 0 1 0 0 Head of Research & Development Stock Option (Right to Buy) 2.89 2019-04-02 4 A 0 375000 0.00 A 2029-03-03 Common Stock 375000 375000 D 25% of this option vests on March 4, 2020, and the remainder vests in equal monthly installments thereafter over 36 months. The option has been granted pursuant to an inducement award agreement outside of the company's 2014 Stock Option and Incentive Plan as a material inducement to the reporting person's acceptance of employment with the company in accordance with NASDAQ Listing Rule 5635(c)(4). The option is subject to acceleration upon a change in control. /s/ Shoaib Ghias, Attorney-In-Fact 2019-04-04