pSivida's BrachySil takes first step in regulatory programme leading to product approval

May 3 2005

pSivida Limited has announced that current data from its lead cancer product BrachySil will be presented at this year's European Society for Therapeutic and Radiation Oncology Conference in Budapest on May 5, 2005. The conference is an opportunity to share and validate the Company's promising findings with an international scientific, clinical and industrial audience.

Data on all eight planned patients has demonstrated marked tumor regression as determined by CT scanning, up to 100% in some smaller tumors. This study represents the first step in the regulatory programme leading to product approval and was specifically focussed on the safety and tolerability of this proprietary treatment for solid tumors. Importantly the study has found that all patients tolerated study procedures and the investigational treatment well, with no significant product-related findings and with all patients discharged from the clinic the day following treatment.

BrachySil is a micron-sized particle in which the isotope 32 phosphorus is immobilised. pSivida believes that this product is advantageous in that it demonstrates a high degree of isotope targeting and retention, thus maximising the therapeutic load on the tumor whilst reducing the risk of radioactivity affecting healthy hepatic tissue or entering the systemic circulation; a finding borne out by the data from this critical study.

pSivida's commercialisation strategy as an R&D-focussed business is to seek a sales and marketing partner for the product.

pSivida also announced on the 8th April 2005 that the Company would be commencing a Phase IIa human clinical trial using BrachySil later this year for pancreatic tumors as a second market for BrachySil, in addition to liver tumors. It is expected that the BrachySil product will also be applicable to a range of other solid tumor cancer markets, which the Company intends to progressively address.