X0306 4 2017-01-03 0 0001302573 OncoMed Pharmaceuticals Inc OMED 0001553352 Lewicki John A. C/O ONCOMED PHARMACEUTICALS, INC. 800 CHESAPEAKE DRIVE REDWOOD CITY CA 94063 0 1 0 0 EVP, Research & Development Common Stock 2017-01-03 4 M 0 9175 1.43 A 40811 D Common Stock 2017-01-03 4 S 0 9175 7.6343 D 31636 D Common Stock 84815 I See Footnote Stock Option (Right to Buy) 1.43 2017-01-03 4 M 0 9175 0.00 D 2017-01-11 Common Stock 9175 0 D Stock Option (Right to Buy) 7.66 2017-01-03 4 A 0 65000 0.00 A 2027-01-02 Common Stock 65000 65000 D Transaction made pursuant to a 10b5-1 trading plan adopted by the Reporting Person on June 16, 2016. Includes 27,500 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 $7.56 to $7.825, inclusive. The price reported in Column 4 above reflects the weighted average sale 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 shares are held by John Allan Lewicki and Jenniffer Joan Lewicki, Trustees of the Lewicki Family Trust dated December 6, 2000. The option is fully vested and exercisable, subject to an annual limitation of 175,438 shares that can be issued to a single grantee upon the exercise of awards under the Issuer's 2004 Stock Incentive Plan. The option vests with respect to 1/48 of the shares subject thereto on each monthly anniversary of the date of grant, 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 John A. Lewicki 2017-01-05