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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION
Washington, DC 20549

 

SCHEDULE 13G/A

 

Under the Securities Exchange Act of 1934

(Amendment No. 1)*

 

Acceleron Pharma Inc.

(Name of Issuer)

Common Stock, par value $0.001 per share

(Title of Class of Securities)

00434H108

(CUSIP Number)

December 31, 2014

(Date of Event Which Requires Filing of this Statement)

 

 

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

 

x Rule 13d-1(b)

o Rule 13d-1(c)

o Rule 13d-1(d)

 

 

*The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page.

 

The information required in the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

 

CUSIP No. 00434H108

SCHEDULE 13G/A

Page 2 of 9 Pages

1	NAME OF REPORTING PERSONS   OrbiMed Advisors LLC
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) o (b) o
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION   Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		5	SOLE VOTING POWER   0
		6	SHARED VOTING POWER   0
		7	SOLE DISPOSITIVE POWER   0
		8	SHARED DISPOSITIVE POWER   0
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON   0
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES			o
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)   0%
12	TYPE OF REPORTING PERSON   IA

CUSIP No. 00434H108

SCHEDULE 13G/A

Page 3 of 9 Pages

1	NAME OF REPORTING PERSONS   OrbiMed Capital GP II LLC
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) o (b) o
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION   Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		5	SOLE VOTING POWER   0
		6	SHARED VOTING POWER   0
		7	SOLE DISPOSITIVE POWER   0
		8	SHARED DISPOSITIVE POWER   0
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON   0
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES			o
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)   0%
12	TYPE OF REPORTING PERSON   OO

 

CUSIP No. 00434H108

SCHEDULE 13G/A

Page 4 of 9 Pages

1	NAME OF REPORTING PERSONS   Samuel D. Isaly
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) o (b) o
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION   United States
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		5	SOLE VOTING POWER   0
		6	SHARED VOTING POWER   0
		7	SOLE DISPOSITIVE POWER   0
		8	SHARED DISPOSITIVE POWER   0
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON   0
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES			o
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)   0%
12	TYPE OF REPORTING PERSON   IN

 

CUSIP No.  00434H108

SCHEDULE 13G/A

Page 5 of 9 Pages

 

Acceleron Pharma Inc.

(b) Address of Issuer’s Principal Executive Offices:

128 Sidney Street

Cambridge, MA 02139

United States

Item 2.

(a) Name of Person Filing:

This Schedule 13G is being filed by each of the following persons (each, a “Reporting Person” and together, the “Reporting Persons”):

(i)  OrbiMed Advisors LLC ("Advisors")

(ii) OrbiMed Capital GP II LLC ("GP II")

(iii) Samuel D. Isaly ("Isaly")

See Exhibit A for the Reporting Persons’ agreement for a joint filing of a single statement on their behalf.

(b) Address of Principal Business Office:

The address of the principal business office of each of Advisors, GP II and Isaly is 601 Lexington Avenue, 54th Floor, New York, NY 10022.

(c) Citizenship:

Please refer to Item 4 on each cover sheet for each filing person.

(d) Title of Class of Securities:

Common Stock, par value $0.001 per share (the “Common Stock”)

(e) CUSIP No.:

00434H108

 

CUSIP No. 00434H108

SCHEDULE 13G/A

Page 6 of 9 Pages

 

 

 

 

CUSIP No. 00434H108

SCHEDULE 13G/A

Page 7 of 9 Pages

 

 

Item 4. Ownership:

 

(a) Amount beneficially owned: See the response(s) to Item 9 on the attached cover page(s).

(b) Percent of class: See the response(s) to Item 11 on the attached cover page(s).

(c) Number of shares as to which the person has:

(i) Sole power to vote or to direct the vote: See the response(s) to Item 5 on the attached cover page(s).

(ii) Shared power to vote or to direct the vote: See the response(s) to Item 6 on the attached cover page(s).

(iii) Sole power to dispose or to direct the disposition of: See the response(s) to Item 7 on the attached cover page(s).

(iv) Shared power to dispose or to direct the disposition of: See the response(s) to Item 8 on the attached cover page(s).

Item 5. Ownership of Five Percent or Less of a Class.

If this Statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than five percent of the class of securities, check the following. x

Item 6. Ownership of More Than Five Percent on Behalf of Another Person.

Not Applicable.

Item 7. Identification and Classification of the Subsidiary which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.

 

Not Applicable.

Item 8. Identification and Classification of Members of the Group.

 

Not Applicable.

Item 9. Notice of Dissolution of Group.

 

Not Applicable.

Item 10. Certification.