X0306 4 2016-01-11 0 0001302573 OncoMed Pharmaceuticals Inc OMED 0001553335 Dupont Jakob C/O ONCOMED PHARMACEUTICALS, INC. 800 CHESAPEAKE DRIVE REDWOOD CITY CA 94063 0 1 0 0 SVP & Chief Medical Officer Common Stock 2016-01-11 4 M 0 2500 4.56 A 23142 D Common Stock 2016-01-11 4 S 0 2500 20.0084 D 20642 D Stock Option (Right to Buy) 4.56 2016-01-11 4 M 0 2500 0.00 D 2021-10-24 Common Stock 2500 138937 D Transaction made pursuant to a 10b5-1 trading plan adopted by the Reporting Person on June 5, 2015. Includes 15,000 restricted stock units. The Reporting Person is entitled to receive one (1) share of common stock for each one (1) restricted stock unit. This transaction was executed in multiple trades in prices ranging from $20.00 to $20.08, inclusive. The price reported in Column 4 above reflects the weighted average sales price. The Reporting Person hereby undertakes to provide to the Securities and Exchange Commission staff, the Issuer, or a security holder of the Issuer, upon request, full information regarding the number of shares sold at each respective price within the range set forth in this footnote. The option was immediately exercisable in full on October 24, 2011; however, the shares vest pursuant to the following schedule: Twenty Percent (20%) of the shares subject to the option vest on the first anniversary measured from October 1, 2011 (the "Vesting Commencement Date") and the remaining shares subject to the option vest in 48 successive, equal monthly installments thereafter on each monthly anniversary of the Vesting Commencement Date, subject to the Reporting Person's continued employment or service relationship with the Issuer on each such vesting date. /s/ Alicia J. Hager, Attorney-in-Fact for Jakob Dupont 2016-01-12