Sec Form 4 Filing - InterWest Management Partners X, LLC @ TESARO, Inc. - 2013-08-05

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 InterWest Management Partners X, LLC 2. Issuer Name and Ticker or Trading Symbol TESARO, Inc. [ TSRO] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner _____ Officer (give title below) X __ Other (specify below) Former 10% Owner (Last) (First) (Middle) 2710 SAND HILL ROAD, SUITE 200 3. Date of Earliest Transaction (MM/DD/YY) 08/05/2013 (Street) MENLO PARK, CA94025 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) _____ Form filed by One Reporting Person __ X __ 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 08/05/2013 J( 1 ) 600,000 D $ 0 2,471,701 D ( 2 )

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 InterWest Management Partners X, LLC 2710 SAND HILL ROAD SUITE 200 MENLO PARK, CA94025 Former 10% Owner Desai Keval 2710 SAND HILL ROAD SUITE 200 MENLO PARK, CA94025 Former 10% Owner Fisher Douglas 2710 SAND HILL ROAD SUITE 200 MENLO PARK, CA94025 Former 10% Owner NASR KHALED 2710 SAND HILL ROAD SUITE 200 MENLO PARK, CA94025 Former 10% Owner Signatures /s/ W. Stephen Holmes, Managing Director 08/07/2013 Signature of Reporting Person Date /s/ Keval Desai by Karen A. Wilson Power of Attorney 08/07/2013 Signature of Reporting Person Date /s/ Douglas C. Fisher by Karen A. Wilson Power of Attorney 08/07/2013 Signature of Reporting Person Date /s/ Khaled A. Nasr by Karen A. Wilson Power of Attorney 08/07/2013 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Represents pro rata in-kind distribution of 600,000 shares by InterWest Partners X, LP ("IW10)" without consideration to its limited and general partners in accordance with the terms of the InterWest X, LP Limited Partnership Agreement. ( 2 )The shares are owned by InterWest Partners X, LP ("IW10"). InterWest Management Partners X, LLC ("IMP10") is the general partner of IW10. Bruce A. Cleveland, Philip T. Gianos, W. Stephen Holmes, Nina S. Kjellson, Gilbert H. Kliman, Arnold L. Oronsky, and Douglas A. Pepper are managing directors of IMP10. Keval Desai, Douglas Fisher and Khaled A. Nasr are venture members of IMP10. Each managing director and venture member of IMP10 disclaims beneficial ownership of such shares, except to the extent of their pecuniary interest therein.

Remarks: Due to limitations of the EDGAR software, this Form 4 is filed on behalf of InterWest Partners X, LLC and certain other Reporting Persons,and is being filed on two Forms 4 (Part I and Part II) (collectively, the "InterWest Form 4"). This filing representsPart II of the InterWest Form 4 and should be read together with Part I. Part I and Part II of the InterWest Form 4 shall constituteone filing.

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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