Altus Pharmaceuticals Announces Pricing of its Initial Public Offering.

CAMBRIDGE, Mass. -- Altus Pharmaceuticals Inc. today announced the initial public offering of 7,000,000 shares of its common stock at a price of $15.00 per share. Shares of Altus' common stock will be traded on the Nasdaq National Market beginning January 26, 2006 under the trading symbol "ALTU". Altus has granted the underwriters of the initial public offering a 30-day over-allotment option to purchase an additional 1,050,000 shares. Merrill Lynch & Co. and Morgan Stanley were joint bookrunning managers for the offering. SG Cowen & Co., LLC was co-manager for the offering.

Net proceeds from the offering are expected to be approximately $95 million, or $110 million if the underwriters exercise their over-allotment option in full, after deducting the underwriting discounts and commissions and the estimated offering expenses. The public offering is being made by means of a written prospectus. Copies of the final prospectus relating to the offering may be obtained from: Merrill Lynch & Co., 4 World Financial Center, New York, New York 10080 or Morgan Stanley Prospectus Department/Dominick Ruscitti, 180 Varick Street, New York, New York 10014.

This press release shall not constitute an offer to sell or the solicitation of an offer to buy nor shall there be any sale of these securities in any state or jurisdiction in which such an offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state or jurisdiction.

About Altus Pharmaceuticals Inc.

Altus Pharmaceuticals is a company focused on the development and commercialization of oral and injectable protein therapeutics for patients with chronic gastrointestinal and metabolic disorders.