Cambridge, MA
June 5, 2007

Gloucester Pharmaceuticals, Inc., a privately held cancer therapeutics development company, today announced that data for romidepsin as a treatment for cutaneous T-cell lymphoma (CTCL) and peripheral T-cell lymphoma (PTCL) were presented at the American Society of Clinical Oncology (ASCO) Annual Meeting being held in Chicago, IL. The data presented are part of an interim analysis of a phase II study of romidepsin sponsored by the National Cancer Institute (NCI) under a Cooperative Research and Development Agreement (CRADA) with Gloucester.

Data from the NCI's ongoing clinical trial of romidepsin was presented in Abstract #8027 "Phase II Trial of Depsipeptide in Patients with Cutaneous T-Cell Lymphoma and Relapsed Peripheral T-Cell Lymphoma" on Monday, June 4th.

The interim results reported on 70 patients with CTCL and 39 patients with PTCL. In the CTCL patient group 4 of 70 patients, or 6%, achieved a complete response, with the duration of response ranging from 8 to 63+ months. A partial response was observed in 18 of 70 patients, or 26%, with the duration of response ranging from 1 to 69+ months. The most common adverse events reported were nausea, vomiting, fatigue, transient granulocytopenia and thrombocytopenia, and anorexia.

Commenting on the data from the NCI's study, William McCulloch, M.B., FRCP, Executive Vice President and Chief Medical Officer at Gloucester said, "Clinical evidence for romidepsin's value in the treatment of T-cell lymphomas continues to build. Based on the data from this trial, as well as interim data from our own Gloucester-sponsored CTCL pivotal phase II study which is nearing completion, we remain enthusiastic about the clinical prospects for romidepsin."

In the PTCL patient group 3 of 39 patients, or 7%, achieved a complete response, with the duration of response ranging from 9 to 43+ months. A partial response was observed in 8 of 39 patients, or 21%, with the duration of response ranging from 2 to 16+ months. The most common adverse events reported were nausea, vomiting, fatigue, transient granulocytopenia and thrombocytopenia, and anorexia.

" We are impressed about the durability of responses, including both CRs and PRs, that have been seen in the PTCL patients thus far." said Jean Nichols, Ph.D., Executive Vice President and Chief Scientific Officer at Gloucester. "Based on the positive data from this study, we recently commenced a multinational pivotal phase II study of romidepsin in PTCL patients who have relapsed or become refractory following systemic therapy," she concluded.

About CTCL
CTCL is a group of diseases, including Mycosis Fungoides and Sézary syndrome, all constituting types of non-Hodgkin's lymphoma in which certain cells of the lymph system (T-cells) become cancerous and affect the skin. The disorder is characterized by abnormal accumulation of malignant T-cells in the skin, which result in the development of itchy rashes, plaques and tumors. Occasionally malignant cells can be found circulating in the bloodstream and visceral (internal organ) involvement can occur. Symptoms of the disorder often include pruritus, an intense itching sensation, which leads to scratching that may cause breaks in the skin that lead to infection. In some patients, pruritus can be so severe that it affects overall quality of life. There are about 40,000 CTCL patients worldwide.

About PTCL
Peripheral T-cell lymphoma is a term which encompasses a number of different malignancies of T-cell origin that account for about 10-15% of all cases of non-Hodgkin's lymphoma. PTCL can occur at any age from young adulthood to old age and is slightly more common in men than in women. It is a particularly aggressive form of lymphoma with a short median duration of life expectancy (approximately two years) from diagnosis.

About Romidepsin
Romidepsin is a novel agent in a new class of anti-cancer drugs known as histone deacetylase inhibitors. The Company is conducting a pivotal phase II study of romidepsin for patients with cutaneous T-cell lymphoma (CTCL) and has initiated a pivotal phase II study for patients with peripheral T-cell lymphoma (PTCL). Romidepsin has received Orphan Drug Designation from the Food and Drug Administration (FDA) for the treatment of non-Hodgkin T-cell lymphomas, which includes CTCL and PTCL. In addition, the European Agency for the Evaluation of Medicinal Products (EMEA) has issued Orphan Drug status for the treatment of both CTCL and PTCL. Fast Track status for CTCL and PTCL has also been designated by the FDA. Romidepsin is in clinical trials for a variety of other hematological malignancies and solid tumors, including hormone refractory prostate cancer, pancreatic cancer and multiple myeloma. These trials and others are being conducted by the Company or the National Cancer Institute (NCI) under a Cooperative Research and Development Agreement (CRADA) with the Company.

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 patients. Gloucester is headquartered in Cambridge, MA. For more information on Gloucester and our clinical development program visit our website at www.gloucesterpharma.com or call 888-GPI-CTCL (888-474-2825).