SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 SCHEDULE 13D/A (Rule 13d-101) UNDER THE SECURITIES EXCHANGE ACT OF 1934 (Amendment No. 1) Radius Health, Inc. Common Stock, par value $0.0001 per share (Title of Class of Securities) None (CUSIP Number) Brookside Capital Partners Fund, L.P. John Hancock Tower 200 Clarendon Street Boston, Massachusetts 02116 (617) 516-2000 (Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications) December 31, 2013 (Date of Event Which Requires Filing of This Statement) If the filing person has previously filed a statement on Schedule 13G to report the acquisition which is the subject of this Schedule 13D, and is filing this schedule because of Rule 13d-1(e), 13d-1(f) or 13d-1(g), check the following box Note. Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See Rule 13d-7 for other parties to whom copies are to be sent. (Continued on following pages) (Page 1 of 6 Pages) CUSIP No. 87612C100 13D/A Page 2 of 6 Pages 1. NAME OF REPORTING PERSONS S.S. OR I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS Brookside Capital Partners Fund, L.P. EIN No.: 04-3313066 2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) X (b) 3. SEC USE ONLY 4. SOURCE OF FUNDS WC 5. CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) or 2(e) 6. CITIZENSHIP OR PLACE OF ORGANIZATION Delaware NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH 7. SOLE VOTING POWER 0 shares 8. SHARED VOTING POWER 2,124,805 (1) 9. SOLE DISPOSITIVE POWER 0 shares 10. SHARED DISPOSITIVE POWER 2,124,805 (1) 11. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 2,124,805 shares of Common Stock (1) 12. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES 13. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 7.1% 14. TYPE OF REPORTING PERSON PN (1) The Reporting Person is party to certain agreements with the Separately Filing Group Members (as defined in the Existing Schedule 13D defined below), which agreements contain, among other things, certain voting agreements and limitations on the sale of the Reporting Person's shares of Common Stock. As a result, the Reporting Person may be deemed to be a member of a "group," within the meaning of Section 13(d)(3) of the Act (as defined in this Schedule 13D/A), comprised of the Reporting Person and the Separately Filing Group Members. Shares listed as beneficially owned by the Reporting Person exclude shares held by any of the Separately Filing Group Members, in each case as to which the Reporting Person disclaims beneficial ownership. The percentage is calculated based upon 35,002,080 shares of outstanding Common Stock being deemed issued and outstanding, which consists of: (i) 879,370 shares of Common Stock that are issued and outstanding and (ii) an aggregate of 34,122,710 shares of Common Stock issuable upon conversion of all shares of Preferred Stock outstanding as of December 31, 2013 following the issuance of the Dividend Shares (as defined in this Schedule 13D/A) as disclosed in the Issuer's Quarterly Report on Form 10-Q, filed with the SEC on November 14, 2013, and as disclosed to the Reporting Person by the Issuer separately. Because shares of Preferred Stock vote together with Common Stock on an as-converted basis, such percentage reflects the Reporting Person's voting percentage of the Issuer's outstanding capital stock. If the percentage calculation was calculated in accordance with Rule 13d-3(d)(1) promulgated under the Exchange Act, excluding shares held by any of the Separately Filing Group Members, as to which the Reporting Person disclaims beneficial ownership, it would result in an applicable percentage of 72.9%. Item 1. Security and Issuer This Schedule 13D/A relates to shares of Common Stock, $0.0001 par value per share (the "Common Stock") of Radius Health Inc., a Delaware corporation (the "Issuer"). The principal executive offices of the Issuer are located at 201 Broadway, 6th floor, Cambridge, Massachusetts 02139. Item 2. Identity and Background (a) This Statement is being filed on behalf of Brookside Capital Partners Fund, L.P., a Delaware limited partnership (the "Brookside Fund"). Brookside Capital Investors, L.P., a Delaware limited partnership ("Brookside Investors") is the sole general partner of the Brookside Fund. Brookside Capital Management, LLC, a Delaware limited liability company ("Brookside Management"), is the sole general partner of Brookside Investors. (b) The principal business address of each of the Brookside Fund, Brookside Investors, and Brookside Management is John Hancock Tower, 200 Clarendon Street, Boston, MA, 02199 (c) The principal business of the Brookside Fund is that of an investment partnership. (d) None of the Brookside Fund, Brookside Investors, or Brookside Management, during the last five years, has been convicted in a criminal proceeding (excluding traffic violations or similar misdemeanors). (e) None of the Brookside Fund, Brookside Investors, or Brookside Management has, during the last five years, been a party to a civil proceeding of a judicial or administrative body of competent jurisdiction and as a result of such proceeding was or is subject to a judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws or finding any violation with respect to such laws. (f) Each of Brookside Fund, Brookside Investors and Brookside Management is organized under the laws of the State of Delaware. The Reporting Persons may be deemed to be members of a "group," within the meaning of Section 13(d)(3) of the Act, comprised of the Reporting Persons and the other persons referred to on Schedule A attached to this Schedule 13D/A (the "Separately Filing Group Members"). It is the understanding of the Reporting Persons that the Separately Filing Group Members are filing separate Schedule 13Ds pursuant to Rule 13d-1(k)(2) under the Act. Schedule A attached to this Schedule 13D/A sets forth certain information concerning the Separately Filing Group Members, which information is based solely on the information contained in the Schedule 13Ds filed by the Separately Filing Group Members or on information provided separately to the Reporting Persons by the Issuer. Item 3. Source and Amount of Funds or Other Consideration The source of funds for the purchases of the Issuer's securities was the working capital of the Brookside Fund. Item 3 is hereby supplemented to add the following: On April 23, 2013, pursuant to the terms of that certain Series B Convertible Preferred Stock and Warrant Purchase Agreement (the "Series B Stock Purchase Agreement"), dated as of April 23, 2013, among the Issuer and the investors referenced therein (the "Series B Investors"), the Issuer issued to the Series B Investors (i) an aggregate of 700,098 shares (the "Series B Shares") of its Series B Convertible Preferred Stock, par value $.0001 per share, and (ii) warrants to purchase, for an initial exercise price of $6.142 per share, up to an aggregate of 1,750,248 shares of Common Stock (the "Warrants" and together with the Series B Shares, the "New Securities"). Such New Securities were issued in connection with the consummation of the initial closing contemplated by the Series B Stock Purchase Agreement in exchange for aggregate proceeds received by the Issuer of $43,000,019.16 (the "Initial Series B Closing"). The issuance of the New Securities resulted in an adjustment to the conversion price (the "Anti-Dilution Adjustment") at which each share of the Issuer's Series A-1 Stock is convertible into shares of Common Stock. As a result of the Anti-Dilution Adjustment, the effective conversion price of each share of Series A-1 Stock was reduced from $8.142 to $7.629. Accordingly, each share of Series A-1 Stock is convertible into 10.672 shares of Common Stock. As a result, the previously reported 122,820 shares of the Series A-1 Stock held by the Reporting Persons are now convertible into 1,310,735 shares of Common Stock. In connection with the Series B Stock Purchase Agreement, the Reporting Persons purchased 81,407 shares of the Issuer's Series B Convertible Preferred Stock, par value $.0001 per share (the "Series B Shares"), and a Warrant to purchase an additional 203,518 shares of Common Stock of the Issuer (the "Warrant") for an aggregate purchase price of $5,000,017.95. The Series B Shares are convertible into 814,070 shares of Common Stock. The source of the funds for this purchase was the working capital of the Brookside Fund. The final paragraph of Item 3 is hereby amended to read as follows: Following the Merger, the Short-Form Merger and the transactions reported in the Schedule 13D and assuming the conversion of all issued and outstanding shares of preferred stock of the Issuer (the "Preferred Stock") and the exercise of the Warrant, Brookside Fund would own 2,328,323 shares of Common Stock, which includes 1,310,735 shares of Common Stock issuable to Brookside Fund upon the conversion of 122,820 Series A-1 Shares, 814,070 shares of Common Stock issuable to Brookside Fund upon the conversion of 81,407 Series B-1 Shares, and 203,518 shares of Common Stock issuable to Brookside Fund upon the exercise of the Warrant. Item 4. Purpose of Transaction The Brookside Fund acquired the Brookside Capital Shares for investment purposes. Item 5. Interest in Securities of the Company (a) Assuming the conversion of the Preferred Stock, the Brookside Fund is the record owner of the Brookside Fund Shares. To the best knowledge of the Brookside Fund, Brookside Investors, and Brookside Management, no director or executive officer of the Brookside Fund, Brookside Investors, nor Brookside Management owns any shares of the Common Stock or Preferred Stock. Percent of Class: See Line 13 of the cover sheets and the footnotes thereto. The percentage is calculated based upon 35,002,080 shares of outstanding Common Stock being deemed issued and outstanding, which consists of: (i) 879,370 shares of Common Stock that are issued and outstanding and (ii) an aggregate of 34,122,710 shares of Common Stock issuable upon conversion of all shares of Preferred Stock outstanding as of December 31, 2013 following the issuance of the Dividend Shares (as defined in this Schedule 13D/A) as disclosed in the Issuer's Quarterly Report on Form 10-Q, filed with the SEC on November 14, 2013, and as disclosed to the Reporting Person by the Issuer separately. Because shares of Preferred Stock vote together with Common Stock on an as-converted basis, such percentage reflects the Reporting Person's voting percentage of the Issuer's outstanding capital stock. If the percentage calculation was calculated in accordance with Rule 13d-3(d)(1) promulgated under the Exchange Act, excluding shares held by any of the Separately Filing Group Members, as to which the Reporting Person disclaims beneficial ownership, it would result in an applicable percentage of 72.9%. (b) Regarding the number of shares as to which such person has: (i) sole power to vote or to direct the vote: See Line 7 of cover sheets. (ii) shared power to vote or to direct the vote: See Line 8 of cover sheets. (iii) sole power to dispose or to direct the disposition: See Line 9 of cover sheets. (iv) shared power to dispose or to direct the disposition: See Line 10 of cover sheets. Schedule A attached to this Amendment No. 1 sets forth, as of the date hereof, the number of shares owned on an as-converted basis and the percentage of shares as calculated (a) based upon 35,002,080 shares of outstanding Common Stock being deemed issued and outstanding, which consists of: (i) 879,370 shares of Common Stock that are issued and outstanding and (ii) an aggregate of 34,122,710 shares of Common Stock issuable upon conversion of all shares of Preferred Stock outstanding as of December 31, 2013 following the issuance of the Dividend Shares, as disclosed in the Issuer's Quarterly Report on Form 10-Q, filed with the SEC on November 14, 2013, and as disclosed to the Reporting Person by the Issuer separately, and (b) in accordance with Rule 13d-3(d)(1) promulgated under the Exchange Act. All information with respect to the Separately Filing Group Members is based solely on the information contained in the Schedule 13Ds filed by the Separately Filing Group Members or on information provided separately to the Reporting Person by the Issuer. (c) Except as set forth in Item 3 above, none of the Reporting Persons has effected any transaction in the Common Stock during the last 60 days. (d) No other person is known to have the right to receive or the power to direct the receipt of dividends from, or any proceeds from the sale of, the Brookside Fund shares beneficially owned by any of the Reporting Persons. (e) Not applicable. Item 6. Contracts, Arrangements, Understandings or Relationships with Respect to Securities of the Issuer Item 6 is hereby amended and restated in its entirety as follows: Brookside Fund is a party to the Third Amended and Restated Stockholders' Agreement, dated April 23, 2013, by and among the Issuer and the stockholders party thereto, which is attached as Exhibit 4.1 to the Issuer's Current Report on Form 8-K filed with the Securities and Exchange Commission on April 25, 2013 and incorporated by reference herein. Item 7. Material to be Filed as Exhibits Item 7 of the Schedule 13D is supplemented as follows: Exhibit 3 Third Amended and Restated Stockholders' Agreement, dated April 23, 2013, by and among the Issuer and the stockholders party thereto (incorporated by reference from the Issuer's Current Report on Form 8-K filed with the Securities and Exchange Commission on April 25, 2013). SIGNATURES After reasonable inquiry and to the best of its knowledge and belief, the undersigned certifies that the information set forth in this Statement is true, complete and correct. Dated: February 21, 2014 BROOKSIDE CAPITAL PARTNERS FUND, L.P. By: Brookside Capital Investors, L.P. Its general partner By: Brookside Capital Management, LLC Its general partner By: /s/ William E. Pappendick IV Name: William E. Pappendick IV Title: Managing Director Schedule A Certain Information Regarding the Separately Filing Group Members(1) Separately Filing Group Member(2) Outstanding Shares (as converted) Voting % of Outstanding Shares Beneficial Ownership F2 Bioscience III, L.P. 3,256,270 9.3% 82.2% MPM Bioventures III, L.P. 374,221 1.1% 30.6% MPM Bioventures III-QP, L.P. 5,565,906 15.9% 86.7% MPM Bioventures III GMBH & Co. Beteiligungs KG 470,374 1.3% 35.6% MPM Bioventures III Parallel Fund, L.P. 168,049 0.5% 16.5% MPM Asset Management Investors 2003 BVIII LLC 107,724 0.3% 11.2% MPM Bio IV NVS Strategic Fund, L.P. 3,905,915 11.2% 82.3% The Wellcome Trust Limited, as Trustee of the Wellcome Trust 3,062,627 8.8% 77.7% HealthCare Ventures VII, L.P. 2,441,206 7.0% 75.4% OBP IV - Holdings LLC 1,960,754 5.6% 69.4% mRNA II - Holdings LLC 19,643 0.1% 2.2% BB Biotech Ventures II, L.P. 2,350,699 6.7% 73.4% Healthcare Private Equity Limited Partnership 816,676 2.3% 48.2% Biotech Growth N.V. 2,288,012 6.5% 74.2% Ipsen Pharma SAS 184,959 0.5% 17.4% Brookside Capital Partners Fund, L.P. 2,125,202 6.1% 72.6% Julianne Glowacki PhD 93 0.0% 0.0% Raymond F. Schinazi 46,953 0.1% 5.3% David E. Thompson Revocable Trust 22,467 0.1% 2.5% Hostetler Family Trust UTD 3/18/92, Karl Y. Hostetler and Margaretha Hostetler, Co-Trustees 8,195 0.0% 0.9% H. Watt Gregory III 15,188 0.0% 2.3%* The Richman Trust Dated 2/6/83, Douglas D. Richman, Co-Trustee and Eva A. Richman, Co- Trustee 8,131 0.0% 0.9% The Breining Family Trust Dated August 15, 2003 4,631 0.0% 0.5% Dennis A. Carson 533 0.0% 0.1% The Jonnie K. Westbrook Revocable Trust, Dated March 17, 2000, Jonnie K. Westbrook, Trustee 363 0.0% 0.0% Stavros C. Manolagas 91,040 0.3% 10.4% Michael Rosenblatt MD 44,803 0.1% 5.1% Patricia E. Rosenblatt 43,028 0.1% 4.9% Dr. John Potts, Jr and Susanne K. Potts Irrevocable Trust for Stephan K. Potts dated 6-15-05 20,291 0.1% 2.3% John Thomas Potts MD 48,942 0.1% 7.7%** John A. Katzenellenbogen Trust Under Agreement Dated August 2, 1999 40,438 0.1% 4.6% John A. Katzenellenbogen PhD 15,627 0.0 % 1.8 % Bart Henderson 30,468 0.1% 3.5% Board of Trustees of the University of Arkansas 17,333 0.1% 2.0% Benjamin C. Lane 8,125 0.0% 0.9% Ruff Trust, F. Bronson Van Wyck, Trustee 5,487 0.0% 0.6% H2 Enterprises, LLC 5,124 0.0% 0.6% Stavroula Kousteni PhD 421 0.0% 0.0% Robert L. Jilka PhD 572 0.0% 0.1% Robert S. Weinstein MD 421 0.0% 0.0% Teresita M. Bellido PhD 234 0.0% 0.0% Dotty Paquin 891 0.0% 0.1% Thomas E. Sparks Jr. 883 0.0% 0.1% Samuel Ho 833 0.0% 0.1% Charles O'Brien PhD 140 0.0 % 0.0 % Alwyn Michael Parfitt MD 280 0.0 % 0.0 % Barnett Pitzele 266 0.0 % 0.0 % Benita S. Katzenellenbogen PhD 187 0.0 % 0.0 % Kelly Colbourn 102 0.0 % 0.0 % Socrates E. Papapoulos MD 93 0.0 % 0.0 % Tonya D. Goss 66 0.0 % 0.0 % The Kent C. Westbrook Revocable Trust, Dated March 17, 2000, Kent C. Westbrook, Trustee 46 0.0 % 0.0 % Maysoun Shomali 2,383 0.0 % 0.3 % Jonathan Guerriero 14,666 0.0 % 1.7 % E. Kelly Sullivan 937 0.0 % 0.1 % Cecil Richard Lyttle 66,666 0.2 % 47.3 %*** Louis O'Dea 193,087 0.6 % 22.0 % Brian Nicholas Harvey 30,000 0.1 % 21.2 %**** Christopher Miller 63,853 0.2 % 7.3 % Christopher K. Glass, M.D. 1,332 0.0 % 0.2 % Maria Grunwald 13,634 0.0 % 1.6 % Kathleen Welch 9,050 0.0 % 1.0 % * Calculation of beneficial ownership percentage includes 5,124 shares of Common Stock held by H2 Enterprises, LLC, a company with which the Reporting Person is affiliated. ** Calculation of beneficial ownership percentage includes 20,798 options to purchase Common Stock anticipated to be exercisable within 60 days within 60 days of December 31, 2013. *** Calculation of beneficial ownership percentage includes 662,945 options to purchase Common Stock anticipated to be exercisable within 60 days within 60 days of December 31, 2013. **** Calculation of beneficial ownership percentage includes 198,004 options to purchase Common Stock anticipated to be exercisable within 60 days within 60 days of December 31, 2013. (1)All references to the number of shares outstanding are based upon 35,002,080 shares of outstanding Common Stock being deemed issued and outstanding, which consists of: (i) 879,370 shares of Common Stock that are issued and outstanding and (ii) an aggregate of 34,122,710 shares of Common Stock issuable upon conversion of all shares of Preferred Stock outstanding as of as of December 31, 2013 following the issuance of the Dividend Shares, as disclosed in the Issuer's Quarterly Report on Form 10-Q, filed with the SEC on November 14, 2013, and as disclosed to the Reporting Person by the Issuer separately. Because each stockholder of the Issuer is a party to certain agreements with the other stockholders of the Issuer, which agreements contain, among other things, certain voting agreements and limitations on the sale of their shares of Common Stock, each stockholder of the Issuer may be deemed to be a member of a "group," within the meaning of Section 13(d)(3) of the Act (as defined in this Schedule 13D/A). Shares listed as beneficially owned in this table exclude shares held by any Reporting Person or by any of the other Separately Filing Group Members, in each case as to which the Reporting Person disclaims beneficial ownership. (2) See the Schedule 13D (or an amendment thereto to the extent any material change in the facts set forth in any Schedule 13D previously filed by any Separately Filing Group Member has occurred) filed, or that the Reporting Person anticipates will be filed, separately by each Separately Filing Group Member, which includes, or will include, information regarding the filer's jurisdiction of organization, principal business, and address of principal office.