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UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13G

Under the Securities Exchange Act of 1934
(Amendment No. 1)*

Praecis Pharmaceuticals Incorporated

(Name of Issuer)

Common Stock, $0.01 par value

(Title of Class of Securities)

739421105

(CUSIP Number)

January 31, 2006

(Date of Event Which Requires Filing of this Statement)

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

o Rule 13d-1(b)

þ 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).

Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB control number.


CUSIP No.		739421105		Page		2		of		8


1	NAMES OF REPORTING PERSONS:

	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY):
	RA Capital Management, LLC

2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS):
	(a) o
	(b) o

3	SEC USE ONLY:



4	CITIZENSHIP OR PLACE OF ORGANIZATION:

	Delaware

		5	SOLE VOTING POWER:

NUMBER OF			0

SHARES		6	SHARED VOTING POWER:
BENEFICIALLY
OWNED BY			0

EACH		7	SOLE DISPOSITIVE POWER:
REPORTING
PERSON			0

WITH:		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 (SEE INSTRUCTIONS):

	o

11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9):

	0%

12	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS):

	IA


CUSIP No.		739421105		Page		3		of		8


1	NAMES OF REPORTING PERSONS:

	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY):
	Richard H. Aldrich

2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS):
	(a) o
	(b) o

3	SEC USE ONLY:



4	CITIZENSHIP OR PLACE OF ORGANIZATION:

	USA

		5	SOLE VOTING POWER:

NUMBER OF			0

SHARES		6	SHARED VOTING POWER:
BENEFICIALLY
OWNED BY			0

EACH		7	SOLE DISPOSITIVE POWER:
REPORTING
PERSON			0

WITH:		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 (SEE INSTRUCTIONS):

	o

11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9):

	0%

12	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS):

	IN


CUSIP No.		739421105		Page		4		of		8


1	NAMES OF REPORTING PERSONS:

	I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY):
	RA Capital Biotech Fund, L.P.

2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS):
	(a) o
	(b) o

3	SEC USE ONLY:



4	CITIZENSHIP OR PLACE OF ORGANIZATION:

	Delaware

		5	SOLE VOTING POWER:

NUMBER OF			0

SHARES		6	SHARED VOTING POWER:
BENEFICIALLY
OWNED BY			0

EACH		7	SOLE DISPOSITIVE POWER:
REPORTING
PERSON			0

WITH:		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 (SEE INSTRUCTIONS):

	o

11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9):

	0%

12	TYPE OF REPORTING PERSON (SEE INSTRUCTIONS):

	PN

Page 5 of 8

Item 1.

(a) Name of Issuer: Praecis Pharmaceuticals Incorporated (the “Issuer”).

(b) Address of the Issuer’s Principal Executive Offices: 830 Winter Street, Waltham, MA 02451-1420.

Item 2.

(a) Name of Person Filing: This joint statement on Schedule 13G is being filed by Richard H. Aldrich, RA Capital Management, LLC and RA Capital Biotech Fund, L.P., who are collectively referred to as the “Reporting Persons.” Mr. Aldrich (the “Manager”) is the manager of RA Capital Management, LLC (“Capital”), which is the sole general partner of RA Capital Biotech Fund, L.P. (the “Fund”). The Reporting Persons have entered into a Joint Filing Agreement, dated as of the date hereof, a copy of which is filed with this Schedule 13G as Exhibit 1 (which is incorporated herein by reference), pursuant to which the Reporting Persons have agreed to file this statement jointly in accordance with the provisions of Rule 13d-1(k) under the Act.

(b) Address of Principal Business Office: The principal business office of the Reporting Persons with respect to the shares reported hereunder is 111 Huntington Avenue, Suite 610, Boston, Massachusetts 02199.

(c) Citizenship: Capital is a Delaware limited liability company. The Fund is a Delaware limited partnership. The Manager is a U.S. citizen.

(d) Title and Class of Securities: Common stock, $0.01 par value (“Common Stock”)

(e) CUSIP Number: 739421105

Item 3. If this statement is filed pursuant to §§240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:

N/A

Item 4. Ownership:

	(a)		Amount Beneficially Owned: 0

	(b)		Percent of Class: 0%

	(c)		Number of Shares as to which such person has:

	(i)		sole power to vote or to direct the vote: 0

	(ii)		shared power to vote or direct the vote: 0

	(iii)		sole power to dispose or to direct the disposition of: 0

	(iv)		shared power to dispose or to direct the disposition of: 0

Page 6 of 8

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 ý.

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

N/A

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

N/A

Item 8. Identification and Classification of Members of the Group

N/A

Item 9. Notice of Dissolution of Group

N/A

Item 10. Certification

By signing below I hereby certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect.

Page 7 of 8

Signature

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.


	DATE: February 7, 2006 RA CAPITAL BIOTECH FUND, L.P. By: RA Capital Management, LLC General Partner
	By:	/s/ Richard H. Aldrich
		Richard H. Aldrich
		Manager

	RA CAPITAL MANAGEMENT, LLC
	By:	/s/ Richard H. Aldrich
		Richard H. Aldrich
		Manager

	RICHARD H. ALDRICH
	/s/ Richard H. Aldrich
	Richard H. Aldrich

Page 8 of 8

Exhibit 1

JOINT FILING AGREEMENT

Pursuant to Rule 13d-1(k)(1) under the Securities Exchange Act of 1934, as amended, the undersigned hereby agree, as of February 7, 2006, that only one statement containing the information required by Schedule 13G, and each amendment thereto, need be filed with respect to the ownership by each of the undersigned of shares of common stock of Praecis Pharmaceuticals Incorporated and such statement to which this Joint Filing Agreement is attached as Exhibit 1 is filed on behalf of each of the undersigned.


	RA CAPITAL BIOTECH FUND, L.P. By: RA Capital Management, LLC General Partner
	By:	/s/ Richard H. Aldrich
		Richard H. Aldrich
		Manager

	RA CAPITAL MANAGEMENT, LLC
	By:	/s/ Richard H. Aldrich
		Richard H. Aldrich
		Manager

	RICHARD H. ALDRICH
	/s/ Richard H. Aldrich
	Richard H. Aldrich