Prana surges on new Alzheimer's lead

Shares in Melbourne-based Prana Biotechnology Ltd (ASX:PBT, NASDAQ:PRAN) surged 18 per cent today on news that the company had selected a new, more potent lead compound as a potential preventative therapy and treatment for Alzheimer's disease and related neurodegenerative disorders.

The new compound, PBT-2, is a new 'designer' metal-chelating compound developed through joint research at the University of Melbourne and the Harvard Medical School at Massachusetts General Hospital.

Prana's chief operating officer, Dr Ross Murdoch, today described the new molecule as "a major milestone" for its research program that would bolster the company's strong position in the search for an effective treatment for Alzheimer's disease.

Murdoch said the compound was one of a series that the company's research chemists had developed that exhibited superior metal-chelating properties, and other advantages, over Prana's prototype lead compound, PBT-1 -- the former anti-diarrhoea drug clioquinol.

Dr Ashley Bush, who co-founded Prana in 2000 with Harvard Medical School colleague Dr Rudolf Tanzy, has shown that metal-chelating compounds can remove oxidised copper and zinc ions that cause fragments of a neurotoxic protein, amyloid-beta, to aggregate in brain tissue, forming dense deposits called amyloid plaques.

Bush's hypothesis that metal ions -- particularly copper -- spawn reactive hydroxyl radicals that damage DNA and injure neurons, is now widely accepted in the Alzheimer's research community.

Murdoch says the new lead molecule, PBT-2, has out-performed PBT-1 (clioquinol) in pre-clinical in vitro and in vivo trials.

It is a low molecular weight compound, with good characteristics as an oral drug capable of penetrating the blood-brain barrier.

Prana will begin toxicology tests this year, and expects to conduct a Phase I (safety and efficacy) clinical trial in human volunteers next year.

Library of compounds

Prana's executive chairman, Geoffrey Kempler, has told New York investors the development is "enormously encouraging", because the company's research chemists have developed a whole library of 'designer' metal-chelating compounds.

The molecules not only have application to Alzheimer's disease, but to neurodegenerative disorders like Parkinson's disease, which is also thought to involve oxidative damage induced by metal ions.

The company says Alzheimer's disease affects about 12 per cent of 65-year olds and about 50 per cent of 85-year olds.

Existing Alzheimer's therapies, such as drugs that increase production of the stimulatory neurotransmitter acetylcholine, offer only temporary relief from the onset of symptoms.