SEC Form 4

FORM 4		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 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* INTERWEST PARTNERS X LP (Last) (First) (Middle) 2710 SAND HILL ROAD SUITE 200 (Street) MENLO PARK CA 94025 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol TESARO, Inc. [ TSRO ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director X 10% Owner Officer (give title below) Other (specify below)
	3. Date of Earliest Transaction (Month/Day/Year) 07/03/2012
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) Form filed by One Reporting Person X Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	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	07/03/2012		C		2,627,257(2)	A	(1)	2,627,257	D(3)
Common Stock	07/03/2012		P		444,444	A	$13.5	3,071,701	D(3)

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 (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	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 (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (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: 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
Series B Preferred Stock	(1)	07/03/2012(1)		C			9,195,402	(1)	(1)	Common Stock	2,627,257(2)	$0	0	D(3)

1. Name and Address of Reporting Person* INTERWEST PARTNERS X LP (Last) (First) (Middle) 2710 SAND HILL ROAD SUITE 200 (Street) MENLO PARK CA 94025 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* CASH HARVEY B (Last) (First) (Middle) 2710 SAND HILL ROAD SUITE 200 (Street) MENLO PARK CA 94025 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* CLEVELAND BRUCE A (Last) (First) (Middle) 2710 SAND HILL ROAD SUITE 200 (Street) MENLO PARK CA 94025 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Ehrlich Christopher B (Last) (First) (Middle) 2710 SAND HILL ROAD SUITE 200 (Street) MENLO PARK CA 94025 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* GIANOS PHILIP T (Last) (First) (Middle) 2710 SAND HILL ROAD SUITE 200 (Street) MENLO PARK CA 94025 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Holmes W Stephen (Last) (First) (Middle) 2710 SAND HILL ROAD SUITE 200 (Street) MENLO PARK CA 94025 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Kjellson Nina S (Last) (First) (Middle) 2710 SAND HILL ROAD SUITE 200 (Street) MENLO PARK CA 94025 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Kliman Gilbert H (Last) (First) (Middle) 2710 SAND HILL ROAD SUITE 200 (Street) MENLO PARK CA 94025 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Pepper Douglas A (Last) (First) (Middle) 2710 SAND HILL ROAD SUITE 200 (Street) MENLO PARK CA 94025 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Rosch Thomas L (Last) (First) (Middle) 2710 SAND HILL ROAD SUITE 200 (Street) MENLO PARK CA 94025 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

Explanation of Responses:

1. The Series B Preferred Stock converted into shares of TESARO, Inc. common stock on a 3.5 for 1 basis immediately prior to the closing of the Issuer's initial public offering and had no expiration date.

2. Reflects a 1-for-3.5 reverse stock split which beame effective on June 18, 2012

3. The shares are owned by InterWest Partners X, LP ("IW10"). InterWest Management Partners X, LLC ("IMP10") is the general partner of IW10. Harvey B. Cash, Bruce A. Cleveland, Christopher B. Ehrlich, Philip T. Gianos, W. Stephen Holmes, Nina S. Kjellson, Gilbert H. Kliman, Arnold L. Oronsky, Douglas A. Pepper and Thomas L. Rosch are managing directors of IMP10. Keval Desai 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, LP 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 represents Part I of the InterWest Form 4 and should be read together with Part II. Part I and Part II of the InterWest Form 4 shall constitute one filing.

	/s/ W. Stephen Holmes, Managing Director	07/05/2012
	/s/ Harvey B. Cash by Karen A. Wilson Power of Attorney	07/05/2012
	/s/ Bruce A. Cleveland by Karen A. Wilson Power of Attorney	07/05/2012
	/s/ Christopher B. Ehrlich by Karen A. Wilson Power of Attorney	07/05/2012
	/s/ Philip T. Gianos by Karen A. Wilson Power of Attorney	07/05/2012
	/s/ W. Stephen Holmes	07/05/2012
	/s/ Nina S. Kjellson by Karen A. Wilson Power of Attorney	07/05/2012
	/s/ Gilbert H. Kliman by Karen A. Wilson Power of Attorney	07/05/2012
	/s Douglas A. Pepper by Karen A. Wilson Power of Attorney	07/05/2012
	/s/ Thomas L. Rosch by Karen A. Wilson Power of Attorney	07/05/2012
	** Signature of Reporting Person	Date
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