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* GALAKATOS NICHOLAS (Last) (First) (Middle) C/O MPM ASSET MANAGEMENT 200 CLARENDON ST., 54TH FLOOR (Street) BOSTON MA 02116 (City) (State) (Zip)	2. Date of Event Requiring Statement (Month/Day/Year) 05/17/2011	3. Issuer Name and Ticker or Trading Symbol Radius Health, Inc. [ NONE ]
		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)

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-1 Convertible Preferred Stock	(1)	(1)	Common Stock	1,469,080	(1)	I	See footnote(2)
Series A-2 Convertible Preferred Stock	(1)	(1)	Common Stock	2,178,730	(1)	I	See footnote(3)
Series A-3 Convertible Preferred Stock	(1)	(1)	Common Stock	533,310	(1)	I	See footnote(4)

1. Name and Address of Reporting Person* GALAKATOS NICHOLAS (Last) (First) (Middle) C/O MPM ASSET MANAGEMENT 200 CLARENDON ST., 54TH FLOOR (Street) BOSTON MA 02116 (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* SIMON NICHOLAS J III (Last) (First) (Middle) C/O MPM ASSET MANAGEMENT 200 CLARENDON ST., 54TH FLOOR (Street) BOSTON MA 02116 (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* WHEELER KURT (Last) (First) (Middle) C/O MPM ASSET MANAGEMENT 200 CLARENDON ST., 54TH FLOOR (Street) BOSTON MA 02116 (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. Each share of Series A-1 Convertible Preferred Stock, Series A-2 Convertible Preferred Stock and Series A-3 Convertible Preferred Stock (collectively, the "Preferred Stock") has no expiration date and is convertible at any time, in whole or in part, at the election of the holder at a conversion ratio of 10 shares of Common Stock for every 1 share of Preferred Stock.

2. The shares on a post-conversion basis are held as follows: 1,222,900 by MPM BioVentures III-QP, L.P. ("BV III QP"), 82,220 by MPM BioVentures III, L.P. ("BV III"), 23,680 by MPM Asset Management Investors 2003 BVIII LLC ("AM 2003"), 36,930 by MPM BioVentures III Parallel Fund, L.P. ("BV Parallel") and 103,350 by MPM BioVentures III GmbH & Co. Beteiligungs KG ("BV KG"). MPM BioVentures III GP, L.P. ("MPM III GP") and MPM BioVentures III LLC ("MPM III LLC") are the direct and indirect general partners of BV III QP, BV III, BV Parallel and BV KG. Luke Evnin, Ansbert Gadicke, Nicholas Galakatos, Dennis Henner, Nicholas Simon III, Michael Steinmetz and Kurt Wheeler are the members of MPM III LLC and AM 2003. Each reporting person disclaims beneficial ownership of the securities reported herein except to the extent of his or its respective pecuniary interest therein.

3. The shares on a post-conversion basis are held as follows: 1,813,640 by BV III QP, 121,940 by BV III, 35,110 by AM 2003, 54,770 by BV Parallel and 153,270 by BV KG. Each reporting person disclaims beneficial ownership of the securities reported herein except to the extent of his or its respective pecuniary interest therein.

4. The shares on a post-conversion basis are held as follows: 443,950 by BV III QP, 29,850 by BV III, 8,590 by AM 2003, 13,400 by BV Parallel and 37,520 by BV KG. Each reporting person disclaims beneficial ownership of the securities reported herein except to the extent of his or its respective pecuniary interest therein.

Remarks:

See Form 3 for MPM BioVentures III LLC filed simultaneously herewith for additional members of this joint filing.

	/s/ Nicholas Galakatos	05/19/2011
	/s/ Nicholas J. Simon, III	05/19/2011
	/s/ Kurt Wheeler	05/19/2011
	** Signature of Reporting Person	Date
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