BBC Wednesday, 31 October, 2001, 00:46 GMT

HIV drug combats resistance Resistance is growing to current HIV drugs

A new class of drug may help meet the growing need for medicines to combat the growing problem of resistant strains of HIV.

Trials currently taking place of two drugs in a class known as fusion inhibitors have produced very promising results.

Existing anti-HIV drugs work inside the cell and target viral enzymes which enable the virus to reproduce itself.

However, the virus has the ability to mutate rapidly, and it is estimated that up to 50% of patients have a strain of HIV has developed resistance to the various antiviral treatments.

This means that the therapy options available to them are reduced.

Block entry

The new drugs completely block the ability of HIV to enter the host cell.

As the drugs work in an entirely different way to those already on the market, they are unlikely to contribute to the resistance problem.

One of the new drugs, known as T-20, was given to patients in combination with existing therapies.

In more than half (56%) it reduced the level of HIV infection - known as viral load - by ten-fold.

Some 39% of patients attained a viral load of less than 400 copies/mL. A viral load of less than 500 copies/mL is considered to be very low.

Tests of the second drug, known as T-1249 are less advanced, but initial results are also promising.

Both have been developed by pharmaceutical companies Roche and Trimeris.

Promising

Julian Meldrum, international editor of the website Aidsmap, told BBC News Online: "T-20 and T-1249 are indeed promising drugs for people with HIV who have been treated with other drugs and are running out of treatment options.

"However, they are unlikely to become treatments of first choice for anyone."

Mr Meldrum said that part of the problem was that the drugs had to be delivered by injection. They were also very expensive and complex to take.

"This means they will be useless for the time being for the great majority of people with HIV and AIDS around the world, who don't have access to current antiretrovirals.

"While Roche have made extraordinary efforts to ensure that they can manufacture these drugs, but there is still going to be a very limited supply available for the foreseeable future."

Mark Graver, of the Terrence Higgins Trust, described the drugs as an "exciting development".

However, he added: "As with any new treatment the long-term benefits and potential longer-term side effects remain unknown."

Details of the research were announced at the European Conference on Clinical Aspects and Treatment of HIV-Infection in Athens.

-- Anonymous, October 30, 2001