Altus Pharmaceuticals Reports Dosing First Patient in a Phase 2 Trial of ALTU-238 for Pediatric Growth Hormone Deficiency.

- - Company's Vice President of Clinical Development To Present at The Endocrine Society's 91st Annual Meeting - -

WALTHAM, Mass. -- Altus Pharmaceuticals Inc. (NASDAQ: ALTU) today announced that patient dosing in its Phase 2 trial for ALTU-238 in growth hormone deficiency pediatric subjects began on June 2, 2009. ALTU-238 is a long-acting, extended-release formulation of recombinant human growth hormone (rhGH, somatropin), which is being developed utilizing Altus' proprietary protein crystallization technology. ALTU-238 is a ready-to-use liquid suspension of crystallized rhGH that preserves the structure of the rhGH molecule without the need for pegylation, polymerization, or encapsulation and enables administration through a fine gauge needle. The Phase 2 ALTU-238 pediatric trial is being conducted in approximately 18 clinical sites in the U.S. and targets enrolling 36 growth hormone deficient pediatric patients. ALTU-238 has been studied in a series of Phase 1 and Phase 2 studies in healthy and GH deficiency adults.

"Moving this pediatric trial forward is an important step in re-establishing the value of the ALTU-238 program and Altus," stated Dr. Georges Gemayel, President and Chief Executive Officer of Altus Pharmaceuticals. "This Phase 2 pediatric trial is the fifth clinical study to evaluate ALTU-238. Previous ALTU-238 studies have demonstrated pharmacokinetic and pharmacodynamic (PK/PD) profiles that are supportive of and consistent with a once-per-week dosing regimen."

The Company is also announcing that Kenneth Attie, M.D., Vice President of Clinical Development and Medical Affairs at Altus Pharmaceuticals, will be presenting results from a key Phase 1 study in the ALTU-238 development program at The Endocrine Society's 91st Annual Meeting in Washington, D.C. at the Washington Convention Center on Wednesday, June 10, 2009. The Endocrine Society's Annual Meeting (ENDO) is a leading forum for physicians and other clinicians who treat endocrine conditions, including growth hormone disorders.

Dr. Ken Attie stated, "As we present this Phase 1 data and start the Phase 2 trial, we believe ALTU-238 has the opportunity to demonstrate its unique advantages compared to daily growth hormone products as well as the other long-acting growth hormone candidates that are in development."

Dr. Attie will be presenting a poster entitled, "Pharmacokinetic, Pharmacodynamic and Safety Results of ALTU238, a LongActing, Crystalline Recombinant Human Growth Hormone, in Healthy Adults." The ALTU-238 Phase 1 trial evaluated the safety and PK/PD profile of a single dose of weekly ALTU-238 compared to seven injections of daily growth hormone. ALTU-238 was well tolerated in the one-week study that included 36 healthy, adult subjects. In addition, the Phase 1 PK/PD data is consistent with prior ALTU-238 clinical studies that supported a once-per-week dosing regimen. The Phase 1 trial results also indicate that the ALTU-238 material, produced at the current increased manufacturing scale, performs similarly to the material used in previous ALTU-238 studies.

About Altus Pharmaceuticals Inc.

Altus Pharmaceuticals is a biopharmaceutical company focused on the development and commercialization of oral and injectable protein therapeutics. The Company's website is www.altus.com.

Safe Harbor Statement

Certain statements in this news release concerning Altus' business are considered "forward-looking statements". These statements include, but are not limited to, the expected ALTU-238 advantages compared to daily growth hormone products as well as the other long-acting growth hormone candidates, the timing for patient enrollment in the Phase 2 clinical trial for ALTU-238, and the future of the ALTU-238 program. Any or all of the forward-looking statements in this press release may turn out to be wrong. They can be affected by inaccurate assumptions Altus might make or by known or unknown risks and uncertainties, including, but not limited to the future cost, timing, enrollment and success of ongoing and planned clinical trials; the risk of demonstrating the ultimate potential of ALTU-238; the continuing risks associated with the development and manufacture of products to supply the clinical trials; the unproven safety and efficacy of ALTU-238; and limitations on the ability of Altus to advance the program due to the company's financial condition. Consequently, no forward-looking statement can be guaranteed, and actual results may differ materially from those expressed or implied by any such forward-looking statement. Additional information concerning factors that could cause actual results to materially differ from those in the forward-looking statements is contained in Altus' reports to the Securities and Exchange Commission, including in Item 1A "Risk Factors" in its Quarterly Report on Form 10-Q for the quarter ended March 31, 2009. However, Altus undertakes no obligation to publicly update forward-looking statements, whether because of new information, future events or otherwise.