Sec Form 4 Filing - ROOT JONATHAN D @ OncoMed Pharmaceuticals Inc - 2017-05-16

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

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, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person ROOT JONATHAN D 2. Issuer Name and Ticker or Trading Symbol OncoMed Pharmaceuticals Inc [ OMED] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) 1460 EL CAMINO REAL, SUITE 100 3. Date of Earliest Transaction (MM/DD/YY) 05/16/2017 (Street) MENLO PARK, CA94025 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 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 05/16/2017 S 4,579 D $ 3.5818 14,179 I Directly owned by EP VIII-A ( 1 ) Common Stock 05/16/2017 S 2,321 D $ 3.5818 7,188 I Directly owned by EP VIII-B ( 1 ) Common Stock 121,020 D

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 (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 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 (MM/DD/YY) 7. Title and Amount of Underlying Securities (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 of Derivative Security: 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

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other ROOT JONATHAN D 1460 EL CAMINO REAL SUITE 100 MENLO PARK, CA94025 X Signatures Dale Holladay - Attorney in fact for the reporting person 05/18/2017 Signature of Reporting Person Date

Explanation of Responses:

( 1 )The reported securities are owned directly by each of U.S. Venture Partners VIII, L.P. ("USVP VIII"), USVP VIII Affiliates Fund, L.P. ("AFF VIII"), USVP Entrepreneur Partners VIII-A, L.P. ("EP VIII-A") and USVP Entrepreneur Partners VIII-B, L.P. ("EP VIII-B" and together with USVP VIII, AFF VIII and EP VIII-A, the "USVP VIII Funds"). Presidio Management Group VIII, L.L.C. ("PMG VIII") is the general partner of each of USVP VIII, AFF VIII, EP VIII-A and EP VIII-B and may be deemed to have sole voting and dispositive power over the shares held by the USVP VIII Funds. PMG VIII and each of Irwin Federman, Steven M. Krausz, David Liddle, Jonathan D. Root, Casey M. Tansey and Philip M. Young, the managing members of PMG VIII who may be deemed to share voting and dispositive power over the reported securities, disclaim beneficial ownership of the reported securities held by the USVP VIII Funds except to the extent of any pecuniary interest therein.

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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