pSivida Announces Completion of BrachySil[TM] Dose Ranging Study in Pancreatic Cancer.

WATERTOWN, Mass. -- pSivida Corp. (NASDAQ:PSDV)(ASX:PVA)(FF:PV3), a leading drug delivery company today announced the completion of a second pancreatic clinical trial of BrachySil[TM] (P32 BioSilicon[TM]), a potential new brachytherapy treatment for inoperable pancreatic cancer. Six patients were studied at two centers in the UK (Guy's and St Thomas' NHS Foundation Trust and University Hospital, Birmingham). The study was conducted to determine the safety of escalating radiation doses of the BrachySil[TM] device and to determine an optimum dosing level. Tumor response was also measured as a secondary end point.

The study escalated the absorbed targeted radiation dose by four-fold from the previous study to 400 Gy (Gy or Gray is a unit of absorbed radiation dose due to ionizing radiation). No device related serious adverse events were experienced at the elevated levels and independent dosimetry experts have concluded from the data that 400 Gy is the optimum dose.

The previous safety study presented last year at the American Society of Clinical Oncology-GI showed that BrachySil[TM] in combination with standard chemotherapy (gemcitabine), was well tolerated with no clinically significant adverse events related to the device. Data in the first study showed disease control in 82% of patients. BrachySil[TM] is implanted directly into the tumor and was found to be easily deliverable by endoscopic ultrasound.

"BrachySil[TM] has once again produced encouraging clinical results with 100% of patients experiencing stabilization in tumor growth," said Dr. Paul Ashton, President and CEO of pSivida Corp. "We are very encouraged by the results of both this dose ranging study and the prior safety study."

BrachySil[TM] is a novel oncology product which comprises a combination of BioSilicon[TM] (a proprietary porous silicon) and the isotope 32Phosphorus, a proven anti-cancer therapeutic. It is hoped this product will provide oncologists with an effective and user-friendly new treatment for this disease which has a high unmet clinical need.

Pancreatic cancer is the fourth most frequent cause of cancer death in the United States, and at least 80% of patients present with inoperable locally advanced or metastatic disease. The median survival for these patients following diagnosis is typically less than six months with standard chemotherapy. Accordingly, there is significant clinical and market demand for effective therapies.

About pSivida Corp.

pSivida is a world leader in the development of tiny, sustained release, drug delivery products that are administered by implantation, injection or insertion. pSivida's lead development product delivers fluocinolone acetonide (FA) for the treatment of diabetic macular edema (DME). This product candidate, formerly known as Medidur[TM] FA for DME, is licensed to Alimera, which is conducting fully recruited Phase III clinical trials and intends to commercialize the product under the name Iluvien[R]. pSivida also has two products approved by the Food and Drug Administration (FDA): Retisert([R]) for the treatment of uveitis and Vitrasert([R]) for the treatment of AIDS-related cytomegalovirus (CMV) retinitis. pSivida has licensed both of these products and the technologies underlying them to Bausch & Lomb Incorporated. pSivida has a worldwide collaborative research and license agreement with Pfizer Inc. under which Pfizer may develop additional ophthalmic products.

pSivida owns the rights to develop and commercialize a modified form of silicon known as BioSilicon[TM], which has potential therapeutic applications. The most advanced BioSilicon product candidate, BrachySil[TM], delivers a therapeutic P32, a radioactive form of phosphorus used to treat cancer, directly to solid tumors. pSivida has completed an initial safety clinical trial of BrachySil for the treatment of pancreatic cancer and is nearing completion of a follow-on dose-ranging clinical trial.

pSivida's intellectual property portfolio consists of 62 patent families, over 100 granted patents, including patents accepted for issuance, and over 200 patent applications. pSivida conducts its operations from Boston in the United States and Malvern in the United Kingdom.

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