Oxford Glycosciences has suspended trials of its most significant drug just a few months before US regulators are due to decide if it is safe to launch.
The biotech company said the suspension was a precaution after a former patient began suffering from a condition that looked like Alzheimer's disease. OGS said it hoped the trials could be resumed in "a relatively few number of weeks", but the shares plunged 14 per cent, their lowest for two-and-a-half years.
Vevesca, OGS's lead drug, is a treatment for Gaucher's disease, a rare genetic disorder, largely confined to Ashkenazi Jews, where the body has difficulty breaking down fat. Although there are little more than 3,000 sufferers, analysts believe the drug could have peak sales of more than £50m a year if it gets approved. Vevesca aims to displace the existing treatment, which is the most expensive drug treatment in the world.
But there have been growing fears over its safety. The company has already admitted this year that a number of patients in the latest human trials have suffered neurological problems leading to numbness and tingling.
Stephen Parker, OGS' finance director, said the company increasingly believes the neurological problems are related to the disease itself. "Our task is to convince regulators that it is the disease, not the drug."
The 66-year-old patient whose condition triggered yesterday's suspension stopped taking Vevesca six months ago. Mr Parker said it was unclear if the person's condition was Alzheimer's, which is difficult to diagnose, but that "according to World Health Organisation criteria, a relationship to the drug treatment appears unlikely at this time".
OGS shares have collapsed from almost £30 at the height of the New Economy boom to 355p, down 60p yesterday, as analysts have cut their sales expectations for Vevesca in light of the safety concerns. OGS is also looking for a new chief executive after Michael Kranda said he wanted to return to the US.
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