Glaxo to reveal HIV hope

Further evidence of the growing success of scientists fighting Aids is likely to be announced by Glaxo Wellcome, the drugs company, at an international Aids conference in Washington today.

However, the findings are being treated with caution by some researchers, who fear the rise in cocktail treatments - combinations of two or more drugs to treat HIV, the virus that causes Aids - brings pitfalls.

Glaxo Wellcome, in conjunction with its partner Vertex, a US biotechnology company listed on the Nasdaq stock exchange, will announce results for a combination treatment of two protease inhibitor compounds developed by Vertex.

The paper will describe the effect of using 1592U89 and 141W494 on a a small group of Aids patients. Seven were tested, and it is understood that while two withdrew from the trial because of side-effects the other five had virus levels reduced to undetectable.

The news follows hard on an announcement on Friday for a combination of Glaxo's 3TC and Bristol-Myers Squibb's d4T, which could also reduce HIV in some patients' blood to undetectable levels. But if the patient had previously used a combination of Glaxo's 3TC and its AZT, the new treatment caused a drop of only 50 per cent - not enough, it is believed, to make much difference to the patient's health.

So-called cocktail therapies have proved to be highly promising ways of treating patients. But the conference has also noted that their proliferation will make them more difficult to track, with each new combination needing more and more analysis to show which is the most effective at different stages of the disease.

If a doctor prescribes the wrong drugs, or gives them to a patient in the wrong order, he risks leaving the patient defenceless farther down the road.

"Each choice minimises your future," said Harvard researcher Dr Cal Cohen. "If a doctor guesses wrong, then you're done with plan B and plan A, and have fewer choices for plan C."

Robert Frost, director of the American Foundation for Aids Research, warned of "the growing concern that the order in which we use combinations of drugs will affect therapeutic options in the future".

Because of the ability of HIV to mutate, many Aids patients are now resistant to older treatments, such as Glaxo's AZT.

The sombre note will temper the optimism of the Glaxo findings, which analysts are unconvinced signal any significant impact yet on the company's profitability. Glaxo, though, is desperate to find replacements as fast as it can for its billion-dollar ulcer drug Zantac, sales of which have been hit badly by coming off patent in the US.