Gloucester Pharmaceuticals Reports on Phase 2 Clinical Study Presented at the American Society of Clinical Oncology 2006 Prostate Cancer Symposium; Depsipeptide Shown to Have Clinical Activity in Hormone Refractory Prostate Cancer.

CAMBRIDGE, Mass. -- Gloucester Pharmaceuticals, Inc., a privately held cancer therapeutics development company, today announced encouraging interim data from its phase 2 clinical study investigating the use of the Company's lead product candidate, depsipeptide (FK228), in treating patients with metastatic hormone refractory prostate cancer (HRPC). The data were presented at the recent American Society of Clinical Oncology (ASCO) 2006 Prostate Cancer Symposium which took place in San Francisco, CA. The data were presented in a poster presentation that has been awarded a 2006 ASCO Foundation Merit Award.

In a poster session Johann S. de Bono, MSc, PhD, MD, FRCP of the Royal Marsden NHS Foundation Trust and The Institute of Cancer Research, London, UK presented interim data from 24 patients enrolled in an ongoing phase 2 study evaluating the activity and tolerability of depsipeptide in patients with HRPC. To date, radiological responses were evaluated in 17 patients and prostate specific antigen (PSA) responses were evaluated in 18 patients. Of the patients evaluated for radiological response, one patient achieved a partial response for six months and two patients achieved stable disease for six months. An additional five patients have shown evidence of disease stabilization, but have not yet reached six months. Of the patients evaluated for PSA response, two patients achieved a 50% or greater decrease in PSA, with another patient achieving a 40% fall in PSA.

"The data from the study so far is very promising and I believe that this is the first histone deacetylase inhibitor (HDAC) to show clinical activity in prostate cancer," stated Dr. De Bono, principal investigator of the clinical trial. "Preliminary results of this trial show that depsipeptide as a single agent may have clinically relevant antitumor activity. We have noted a partial response in one patient and have seen disease stabilization in seven other patients. We have also seen significant reductions in PSA in three patients. The drug has been well tolerated, and accrual in the study is ongoing. I look forward to following the response of these patients and possibly initiating additional studies with depsipeptide in the future."

"We are very excited to see evidence of clinical benefit in this important indication," said William McCulloch, M.B., FRCP, Executive Vice-President and Chief Medical Officer at Gloucester Pharmaceuticals. "Prostate cancer is the second leading cause of cancer deaths in men in the United States. We've already generated positive data in clinical trials of depsipeptide for the treatment of certain hematological malignancies, and are pleased that these data suggests clinical activity in solid tumors as well."

About Depsipeptide (FK228)

Depsipeptide (FK228) is one of a new class of anti-cancer agents, known as histone deacetylase inhibitors. Depsipeptide was granted Fast Track and Orphan Drug designations by the Food and Drug Administration and European Orphan Drug designation by the EMEA as a monotherapy for the treatment of cutaneous T-cell lymphoma in patients who have relapsed following, or become refractory to, one other systemic therapy. It is currently being evaluated in a pivotal clinical trial sponsored by Gloucester for this indication. The U.S. Food and Drug Administration (FDA) reviewed the trial protocol under its Special Protocol Assessment (SPA) process prior to the initiation of the pivotal study. Depsipeptide is also being studied in a range of hematologic and solid tumor indications including hormone refractory prostate cancer in clinical trials sponsored by Gloucester, and in clinical trials sponsored by the National Cancer Institute (NCI) under a Cooperative Research and Development Agreement (CRADA).

About Gloucester Pharmaceuticals, Inc.

Gloucester Pharmaceuticals, Inc. is a privately held, venture-backed company that develops and commercializes innovative products for the treatment of cancer. The Company employs an in-licensing strategy to build a diversified product portfolio to address the significant unmet medical need in the management of cancer. Gloucester's first product is depsipeptide, a novel HDAC inhibitor. Gloucester is headquartered in Cambridge, MA. For more information visit our website at www.gloucesterpharma.com.

For more information on Gloucester's clinical trial in prostate cancer, please call 888-GPI-CTCL (474-2825) or visit www.clinicaltrials.gov/ct/show/NCT00106418.