Levin Mark J Form 3 MyoKardia / ROBERT I TEPPER ownership change

SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person^*

Third Rock Ventures II, L.P.

(Last) (First) (Middle)

29 NEWBURY STREET

(Street)

BOSTON MA 02116

(City) (State) (Zip)

2. Date of Event Requiring Statement (Month/Day/Year)
10/28/2015

3. Issuer Name and Ticker or Trading Symbol
MyoKardia Inc [ MYOK ]

4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

Director	X	10% Owner
Officer (give title below)		Other (specify below)

5. 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 Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Common Stock	544,217	D(1)

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Series A Preferred Stock	(2)	(2)	Common Stock	32,500,000	(2)	D(1)
Series A Preferred Stock	(2)	(2)	Common Stock	5,500,000	(2)	D(3)

1. Name and Address of Reporting Person^*

Third Rock Ventures II, L.P.

(Last) (First) (Middle)

29 NEWBURY STREET

(Street)

BOSTON MA 02116

(City) (State) (Zip)

1. Name and Address of Reporting Person^*

Third Rock Ventures GP II, L.P.

(Last) (First) (Middle)

29 NEWBURY STREET

(Street)

BOSTON MA 02116

(City) (State) (Zip)

1. Name and Address of Reporting Person^*

TRV GP II, LLC

(Last) (First) (Middle)

29 NEWBURY STREET

(Street)

BOSTON MA 02116

(City) (State) (Zip)

1. Name and Address of Reporting Person^*

Third Rock Ventures III, L.P.

(Last) (First) (Middle)

29 NEWBURY STREET

(Street)

BOSTON MA 02116

(City) (State) (Zip)

1. Name and Address of Reporting Person^*

Third Rock Ventures GP III, L.P.

(Last) (First) (Middle)

29 NEWBURY STREET

(Street)

BOSTON MA 02116

(City) (State) (Zip)

1. Name and Address of Reporting Person^*

TRV GP III, LLC

(Last) (First) (Middle)

29 NEWBURY STREET

(Street)

BOSTON MA 02116

(City) (State) (Zip)

1. Name and Address of Reporting Person^*

LEVIN MARK J

(Last) (First) (Middle)

29 NEWBURY STREET

(Street)

BOSTON MA 02116

(City) (State) (Zip)

1. Name and Address of Reporting Person^*

TEPPER ROBERT I

(Last) (First) (Middle)

29 NEWBURY STREET

(Street)

BOSTON MA 02116

(City) (State) (Zip)

Explanation of Responses:

1. The shares are directly held by Third Rock Ventures II, L.P. ("TRV II"). The general partner of TRV II is Third Rock Ventures GP II, L.P. ("TRV GP II LP"). The general partner of TRV GP II LP is TRV GP II, LLC ("TRV GP II LLC"). The individual managers of TRV GP III LLC are Mark Levin ("Levin"), Kevin Starr ("Starr") and Dr. Robert Tepper ("Tepper") and, as such, each of TRV GP II LP and TRV GP II LLC, Levin, Starr and Tepper exercises shared voting and investment power over the shares held of record by TRV II. Each of the Reporting Persons disclaims beneficial ownership of the shares except to the extent of their pecuniary interest therein, if any.

2. Each share of the Series A Preferred Stock is convertible into Common Stock on a one-for-3.675 basis automatically upon the closing of the Issuer's initial public offering, and has no expiration date.

3. The shares are directly held by Third Rock Ventures III, L.P. ("TRV III"). The general partner of TRV III is Third Rock Ventures GP III, L.P. ("TRV GP III LP"). The general partner of TRV GP III LP is TRV GP III, LLC ("TRV GP III LLC"). The individual managers of TRV GP III LLC are Levin, Starr and Tepper and, as such, each of TRV GP III LP and TRV GP III LLC, Levin, Starr and Tepper exercises shared voting and investment power over the shares held of record by TRV III. Each of the Reporting Persons disclaims beneficial ownership of the shares except to the extent of their pecuniary interest therein, if any.

Remarks:

	/s/ Third Rock Ventures II, L.P. by Third Rock Ventures GP II, L.P. its general partner by TRV GP II, LLC its general partner	10/28/2015
	/s/ Third Rock Ventures GP II, L.P. by TRV GP II, LLC its general partner	10/28/2015
	/s/ TRV GP II, LLC	10/28/2015
	/s/ Third Rock Ventures III, L.P. by Third Rock Ventures GP III, L.P. its general partner by TRV GP III, LLC its general partner	10/28/2015
	/s/ Third Rock Ventures GP III, L.P. by TRV GP III, LLC its general partner	10/28/2015
	/s/ TRV GP III, LLC	10/28/2015
	/s/ Kevin Gillis by power of attorney for Mark Levin	10/28/2015
	/s/ Kevin Gillis by power of attorney for Robert I. Tepper	10/28/2015
	** Signature of Reporting Person	Date
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