SEC Form 4

FORM 4		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* WARBURG PINCUS PRIVATE EQUITY VIII L P (Last) (First) (Middle) 466 LEXINGTON AVENUE (Street) NEW YORK NY 10017 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol Altus Pharmaceuticals Inc. [ ALTU ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director X 10% Owner Officer (give title below) Other (specify below)
	3. Date of Earliest Transaction (Month/Day/Year) 01/31/2006
	4. 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 Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	01/31/2006(1)		C		3,589,246(2)(3)	A	(3)	3,589,246(2)(3)	D(4)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Series C Convertible Preferred Stock	$0.00	01/31/2006(1)		C			3,589,246(2)(3)	05/21/2004	01/31/2006(1)	Common Stock	3,589,246(2)(3)	$0.00	0	D(4)
Warrant	$9.802	01/31/2006(1)		C		717,917(5)		05/21/2004	05/21/2011	Common Stock	717,917(5)	$9.802	717,917(5)	D(4)

1. Name and Address of Reporting Person* WARBURG PINCUS PRIVATE EQUITY VIII L P (Last) (First) (Middle) 466 LEXINGTON AVENUE (Street) NEW YORK NY 10017 (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* Warburg Pincus Partners LLC (Last) (First) (Middle) 466 LEXINGTON AVENUE (Street) NEW YORK NY 10017 (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* WARBURG PINCUS LLC (Last) (First) (Middle) 466 LEXINGTON AVENUE (Street) NEW YORK NY 10017 (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* WARBURG PINCUS & CO (Last) (First) (Middle) 466 LEXINGTON AVENUE (Street) NEW YORK NY 10017 (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. This is the date of the closing of the Issuer's initial public offering.

2. Includes dividends that had been accruing on the Series C Convertible Preferred Stock and which were paid out in 325,995 shares of common stock as of the date of the closing of the Issuer's intial public offering.

3. All outstanding shares of the Issuer's Series C Convertible Preferred Stock converted to common stock at a rate of .4401933369 - to- 1 upon the completion of the Issuer's initial public offering.

4. The stockholder is Warburg Pincus Private Equity VIII, L.P. ("WP VIII"). Warburg Pincus Partners, LLC ("WPP LLC"), a subsidiary of Warburg Pincus & Co. ("WP"), is the sole general partner of WP VIII. WP VIII is managed by Warburg Pincus LLC ("WP LLC"). The address of the Warburg Pincus entities is 466 Lexington Avenue, New York, New York 10017. Jonathan S. Leff and Stewart J. Hen, directors of the Company, are general partners of WP and managing directors and members of WP LLC. Messrs. Leff and Hen disclaim beneficial ownership of all shares held by the Warburg Pincus entities. Charles R. Kaye and Joseph P. Landy are Managing General Partners of WP and Managing Members of WP LLC and may be deemed to control the Warburg Pincus entities. Messrs. Kaye and Landy disclaim beneficial ownership of all shares held by the Warburg Pincus entities.

5. Warrants were automatically adjusted on a basis of .4401933369 - to- 1 upon closing of the Issuer's public offering. The number of adjusted warrants reported are exercisable for common stock on a 1 for 1 basis.

Remarks:

	/s/ Scott Arenare	02/01/2006
	Scott Arenare	02/02/2006
	Scott Arenare	02/02/2006
	Scott Arenare	02/02/2006
	** Signature of Reporting Person	Date
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