Nanotherapie in combinatie met brachytherapie - inwendige bestraling - en onder de naam BrachySil(TM) (32-P BioSilicon(TM)) geeft uitstekende resultaten bij verwijdering van levertumoren zonder noemenswaardige bijwerkingen.

15 februari 2005: DOW

Nanotherapie in combinatie met brachytherapie - inwendige bestraling - en onder de naam BrachySil(TM) (32-P BioSilicon(TM)) geeft uitstekende resultaten bij verwijdering van levertumoren in fase II trial zonder noemenswaardige bijwerkingen. Van de grotere tumoren bleek binnen 12 weken 80% vermindering van de tumoren, van de kleinere tumoren verdween 100% binnen zes weken na behandeling. Interessant lijkt met deze benadering om dit te combineren met bv. TACE en LITT. We zullen deze studie ook doorsturen naar Dr. Vogl om hier kennis van te nemen. Of neem het zelf mee als u daar naartoe gaat. Is o.i. een zeer interessante ontwikkeling.

-- PRESS RELEASE: pSivida Limited Reports Positive Phase IIa Trial Results in Liver --

PERTH, Australia--(BUSINESS WIRE)--Feb. 14, 2005--Global nanotechnology company pSivida Limited (NASDAQ:PSDV, ASX:PSD, Xetra:PSI) today announced that its trial in inoperable primary liver cancer patients continues to show excellent results. Data from the second patient cohort of the current Phase IIa trial has further demonstrated that BrachySil(TM) (32-P BioSilicon(TM)) is safe and effective in tumor regression with increased efficacy. Results of the second group of four patients, 12 weeks after their BrachySil(TM) treatment, revealed an average tumor regression by volume of 80% as determined by CT scanning. In some smaller tumors 100% regression was observed, a level of performance not seen with other intratumoral approaches. The study also demonstrated that there were no product-related adverse effects. Patients will continue to be monitored for six months post treatment. These excellent results follow the announcement in October 2004 of the interim results from the first four patients, which also showed no product-related adverse effects and reported up to 60% regression of tumors. BrachySil(TM) is a micron-sized particle in which the isotope 32-phosphorus is immobilized. pSivida believes that this product is unique in that it demonstrates a very high degree of isotope retention, thus reducing the risk of soluble radioactive material affecting healthy hepatic tissue, or entering the circulation and causing systemic toxicity. pSivida's Managing Director, Mr. Gavin Rezos, said, "This further human evaluation of BioSilicon(TM) has met our expectations in terms of safety and the performance of the fine gauge needle injection procedure. We are also very pleased with the significant level of tumor regression achieved given the low dose being administered. Proof of the ability of BrachySil(TM) to retain radioactivity at the injection site is another significant outcome of the trial."

Other treatments for primary liver cancer include a variety of embolization and radio frequency ablation techniques. pSivida believes that BrachySil(TM) potentially offers the interventional radiologist a more versatile and safer product for the treatment of such tumors. The procedure is undertaken without surgery under local anesthetic and patients can be discharged the following day. pSivida currently plans to pursue a 'device-based' regulatory approval route for BrachySil(TM), which could result in a much shorter development and registration timeframe than that commonly associated with a drug-based approval. Following the completion of analysis of the final Phase IIa trial results, pSivida expects to begin a dose profiling study during 2005. pSivida then intends to commence multi-center pivotal registration trials during 2005 involving patients in Asia, Europe and the U.S. The objective of these trials is to obtain data to support registration of BrachySil(TM) as an approved treatment for primary liver cancer.
pSivida plans to expand the use of BrachySil(TM) as a treatment for a wider range of solid tumor indications. A Phase IIa clinical trial is scheduled to commence for a second cancer indication within the next year. The brachytherapy market is currently over $600 million (US) per annum and is expected to exceed $1 billion (US) within the next few years (Bio-Tech Systems). BrachySil(TM) has the potential to significantly expand the current market size through its application to other cancers.

The study has established four key findings:

-- SAFETY - No product related adverse events Unlike other liver brachytherapy approaches that involve delivery via the hepatic artery and, in some cases, result in radioactivity affecting healthy tissue, BrachySil(TM) is administered directly into tumors restricting radioactivity to the tumor itself.

-- EFFICACY - Treated tumors demonstrate significant tumor regression Implantation of tumors with BrachySil(TM) has resulted in tumoricidal activity around the implantation site. Although the primary objective of the study was to determine the safety profile of BrachySil(TM), CT scan analysis of tumors at the time of treatment and three months later demonstrates significant tumor regression in targeted lesions with a maximum regression of 100% from the dose used in the trial.

-- SPECIFICITY - Retention of radioactivity in the tumor A key finding is that the radioactive 32P-BioSilicon(TM) nanostructured microparticles remain in the tumor with no or insignificant detectable radioactive leakage.

-- EASE OF APPLICATION - Practical and rapid treatment of tumors with ultrasound and CT guidance The procedure has been shown to be straightforward and accurate for the treatment of tumors. From a market perspective, this demonstration is in line with the company's strategy to develop a simple procedure for the interventional radiologist to selectively treat specific tumors. A multi injector is in design phase to treat larger tumors with multiple implantations from a single entry.

NOTES ON BRACHYSIL AND COMPETITIVE ADVANTAGES IN BRACHYTHERAPY

1. BrachySil(TM) is being manufactured to worldwide regulatory guidelines by supply chain contract partners including HighForce, Micron Group, Atomizing Systems and AEA Technology QSA subsidiary Auriga Medical, a leading global producer and supplier of radioisotopes for healthcare.

2. Brachytherapy treatment utilizing BioSilicon(TM) includes the following significant potential advantages:

-- Short range - 32-P isotope has a short active range resulting in less damage to healthy tissue.
-- Immobilization - 32-P device is immobilized in the tumor, significantly reducing risk of leakage or systemic side effects.
-- Ease of application - BrachySil(TM) is delivered under local anesthetic and patients can be discharged the next day.
-- Direct delivery - BrachySil(TM) is delivered via fine gauge needle, minimizing side effects and tissue trauma without the need for shielded rooms or robotic injectors allowing treatment in hospitals without the need for investment in specialized facilities.
-- Range of tumors - fine gauge needle delivery allows potential application to many solid tumors, unlike current brachytherapy products.
-- Distribution - 32-P half-life of 14 days allows more convenient distribution to hospitals and application in the patient.
-- Manufacture - BioSilicon(TM) is radiation hard, allowing ease of manufacture of BrachySil(TM) from phosphorous-doped silicon used in the electronics industry without the need to build costly manufacturing facilities.

About pSivida Limited

pSivida is a global nanotechnology company committed to the biomedical sector and the development of products in healthcare. The company's focus is the development and commercialization of a modified form of silicon (porosified or nano-structured silicon) known as BioSilicon(TM). As a new and exciting biocompatible material, BioSilicon(TM) offers multiple potential applications across the high growth healthcare sector, including controlled release drug delivery, targeted cancer therapies (including brachytherapy and localized chemotherapy), tissue engineering and orthopedics. Potential diagnostics applications are being developed through its subsidiary AION Diagnostics Limited. More information is available at www.psivida.com.

This document contains forward-looking statements that involve risks and uncertainties. Although the company believes that the expectations reflected in such forward-looking statements are reasonable at this time, it gives no assurance that such expectations will prove to be correct. Given these uncertainties, readers are cautioned not to place undue reliance on such forward-looking statements. Actual results could differ materially from those anticipated in these forward-looking statements due to many important factors including: the company's failure to develop applications for BioSilicon(TM) due to regulatory, scientific or other issues. Other reasons are contained in cautionary statements in the Registration Statement on Form 20-F filed with the U.S. Securities & Exchange Commission, including, without limitation, under Item 3.D., "Risk Factors" therein. The company does not undertake to update any oral or written forward-looking statements that may be made by or on behalf of pSivida.