Prana's [PRAN] positive pilot trial results offer hope for millions of Alzheimer's sufferers, whose treatments are limited by symptomatic effect only. PBT-1 is becoming an increasingly attractive in-licensing opportunity and, assuming safety and disease modifying ability is shown in large trials, it has potential to grab a large share of this multi-billion dollar market.
Australian company Prana has released results of a pilot Phase II clinical trial, which show that treatment with its drug PBT-1 (clioquinol) for moderate to severe Alzheimer's disease (AD) slowed progression of cognitive decline. The findings were published in the December issue of Archives of Neurology.
Compared to those taking placebo, patients taking PBT-1 experienced improved cognitive performance, and a significant lowering in plasma levels of amyloid protein, a key marker of Alzheimer's disease that is thought to contribute to the pathology. PBT-1 was also well tolerated.
Research has shown that excess zinc and copper in the brain can cause beta-amyloid protein to accumulate into plaques found in the brain of AD patients. PBT-1 binds zinc and copper, and has been shown to lower the levels of amyloid beta and the associated toxicity in the brains of transgenic mice models of AD.
The study enrolled 36 patients who were assessed for indicators of cognitive performance such as memory, orientation, language, attention and reasoning using a cognitive score on the Alzheimer's Disease Assessment Scale (ADAS-cog); the standard tool used to assess drug efficacy in AD drug trials.
AD is a degenerative brain disease that affects tens of millions of elderly people worldwide. The market for drug therapies is worth over $2 billion and is dominated by the acetylcholinesterase inhibitor class of drugs, with sales of Pfizer's [PFE] market-leading Aricept (donepezil) expected to exceed $1 billion in 2003. However, current treatments only work to improve the symptoms of AD and cannot delay disease progression. Based on these positive results, PBT-1 represents a favorable in-licensing opportunity. However, it is important that larger trials are conducted to determine the true extent of any disease modifying effect and the clinical benefits this confers.