Epivir, which is approved in the US and awaiting approval in Europe, is one of two leading Aids treatments now made by Glaxo Wellcome. It also manufactures Retrovir, which is also known as AZT.
Glaxo's shares jumped 20.5p, or 2 per cent, to 911.5p as the market focused on the potential profits that might flow from the company's dominance of such an important therapeutic area.
Glaxo said yesterday the independent Data and Safety Monitoring Board had recommended that the experiment be abandoned after late stage trials because the panel had found a 54 per cent reduction in the rate of progression in Aids patients compared with the placebo.
It is usual practice to abandon trials of drugs for life-threatening diseases for ethical reasons when it has become clear that their effectiveness exceeds expectations. A similar trial conducted by SmithKline Beecham was abandoned recently after it became evident that its treatment, Coreg, was unexpectedly effective in treating congestive heart failure.
The end of the trial does not mean automatic approval for the drug. In SmithKline's case the Food and Drug Administration, the US pharmaceuticals watchdog, asked for further research to prove the drugs efficacy.
Glaxo's trial of Epivir started in March 1995 and was scheduled to last for two years, ending next March. Involving nearly 2,000 patients, the trial combined Epivir with Retrovir and put the two together with other drugs in the same class called "reverse transcriptase inhibitors".
The combination of drugs has become an important weapon in the fight against Aids. Results of similar studies were presented to a recent industry conference in Vancouver.
Paul Diggle, an analyst at SG Strauss Turnbull, said: "Expectations for Epivir have been gradually rising."
He added: "Today's news is reinforcing in people's minds that the Aids market is changing and that Glaxo is in an extremely strong position to be the biggest beneficiary of it."Reuse content