Positive results for BrachySil

A Phase IIa BioSilicon trial in man has shown safety and tumour regression. Nanotechnology company pSivida and Singapore General Hospital (SGH) have released interim data analysis from pSivida's phase IIa trial at SGH that has confirmed expectations that BrachySil (32-P BioSilicon) is safe and effective at tumour regression.

The first four patients, all with inoperable liver cancer, have shown no product related adverse side effects and up to 60% regression of tumours.

All eight patients required for the approved trial have received BrachySil treatment at SGH. The interim report announced the results in respect of the first four patients reviewed three months after administration.

BrachySil is expected to be on the market worldwide during 2007 initially for liver cancer and thereafter for the treatment of a wider variety of cancers involving solid tumours following regulatory approvals.

Current brachytherapy style products being 'in the body localised radioactive treatment of tumours' are limited to liver and postrate tumours by virtue of their manner of delivery.

The current brachytherapy market is growing and is estimated to be worth more than US$1bn per year. BrachySil has the potential to significantly expand the current market size through application to other cancers as a result of the successful fine gauge direct needle delivery procedure. The procedure is undertaken without surgery under local anaesthetic and patients were discharged the following day.

This 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 cases, result in radioactivity becoming associated with healthy tissue, BrachySil is administered directly into tumours restricting radioactivity to the tumour itself.

Efficacy - treated tumours demonstrate significant tumour regression. Implantation of tumours with BrachySil has resulted in tumouricidal activity around the implantation site. Although the primary objective of the study was to determine the safety profile of BrachySil, CT scan analysis of tumours at the time of treatment and three months later demonstrates significant tumour regression in all targeted lesions with a maximum regression of 60% from the dose used in the trial.

Specificity - retention of radioactivity in the tumour. A key finding is that the radioactive 32P-BioSilicon nanostructured microparticles remain in the tumour with no or insignificant detectable radioactive leakage. This observation is a very significant outcome for the trial.

Ease of application - practical and rapid treatment of tumours with ultrasound and CT guidance. The procedure established by the principal investigator and his team at SGH has been shown to be straightforward and accurate for the treatment of tumours. 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 tumours. A multi injector is in design phase to treat larger tumours with multiple implantations from a single entry.

pSivida's managing director, Gavin Rezos, said: 'This "first in man" evaluation of BioSilicon has met our expectations on safety and of the needle injection procedure. The ability of BrachySil to retain the radioactivity at the injection site is excellent news.'

He added: 'Product launch for BrachySil is scheduled for 2007, following the Phase IIb trial next year. The expectation that it will follow a "device-based" regulatory route means shorter development and registration timeframes. Second stage commercialisation will target other major cancers to extend the range of potential applications of BrachySil.'