pSivida claims success in anti-tumour device study

A nano-structured silicon device containing slow-release radiotherapy has successfully halted tumours in an animal study.

Australian biotech pSivida (ASX:PSD) announced that its Singapore subsidiary pSiOncology had demonstrated the efficacy of its lead product, 32-P-BioSilicon radiotherapy.

The radiotherapy device is a 20 micron particle containing an "integral immobilised 32-phosphorous isotope within a silicon matrix".

The structure enables the matrix-locked radioactivity to be localised within a tumour, hopefully resulting in regression of the disease.

In pre-clinical trials using animal models bearing the human tumours, 32-P-BioSilicon radiotherapy was shown to reverse the cancer, a company statement said. This followed an earlier trial using the platform technology in chemotherapy, which also showed tumour regression in animal studies.

pSivida managing director Gavin Rezos said the results represented a significant milestone in the product's development.

"This lead product has the potential to provide significant near term revenue and, combined with the earlier successful pre-clinical chemotherapy trials, demonstrates the efficacy of the wider slow-release controlled drug delivery applications of the BioSilicon platform technology," he said.

The matrix can also be loaded with cytotoxic drugs, paving the way for its potentially additional use as a tumour management tool.

The 32-P product falls into the brachytherapy cancer market, a treatment area involving the direct delivery of drugs into cancerous cells in an effort to stop the disease without the side effects of conventional therapies.

The brachytherapy market is estimated to be worth an attractive US$600 million.

"The lack of therapeutics options in many late-stage cancer patients is placing significant emphasis on new technologies such as brachytherapy," Rezos said.

Although potentially applicable to a wide range of tumours, the 32-P product will initially be evaluated in late stage liver cancer patients.

Phase IIa clinical trials are scheduled to begin early in 2004 and will be conducted by the Singapore subsidiary and joint venture partner Singapore General Hospital.

R&D costs boost loss

The company has also released its financial results to the market, which show a consolidated net loss of AUD$5.4 million, up from $4 million in the previous year.

The report shows about 85 per cent of these losses ($4.6 million) were attributable to research and development costs, with the remainder going on administrative expenses.

At the end of June pSivida held cash researches of $1.2 million, down from $5 million the previous year, although a subsequent share purchase plan has added $1.7 million to the company's coffers.

At the time of writing, the company was trading 4.1 per cent higher at 51 cents.