Cautious optimism on AIDS vaccine prospect

The first full day of discussions at the International AIDS Conference got under way in Barcelona yesterday in a mood of tension…

The first full day of discussions at the International AIDS Conference got under way in Barcelona yesterday in a mood of tension, with many of the 15,000 delegates condemning the richer nations for their failure to pay towards the fight against the epidemic.

Only 25 per cent of the $10,000 million pledged at the United Nations Millennium Summit two years ago has so far been raised and the death toll continues to rise almost out of control.

But there were two notes of optimism. First, the news of a drug which has given hopeful results in clinical trials and could be available within months; secondly the announcement by an American pharmaceutical that it is working on a preventive vaccine.

Dr Bonaventura Clotet, a Spanish scientist, has been working with his American colleague Dr Jacob Lalezari on the development of a fusion-inhibiting drug to reduce the HIB count in the blood. He described results of the T-20 drug as "spectacular" after tests on 1,000 cases in 112 hospitals in Europe, the USA and Brazil.

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Dr Clotet said that T-20, taken at the same time as the retroviral cocktail drugs, had been particularly successful on patients who either could not tolerate or had built up a resistance to the drug cocktail.

He described it as a kind of shield which prevents the virus invading and attacking cells in the body. Thirty-seven per cent of patients treated with T-20 had achieved such a dramatic reduction in HIV cells in the blood as to make them virtually undetectable after 24 weeks of treatment, a figure only achieved in 16 per cent of patients treated with the cocktail.

Mr James Lock from London was one of the guinea pigs on the trial and he described his results as "incredible". He had developed a resistance to current drugs, but since he began taking T-20 injections the viral cells in his blood had fallen from 1.3 million per millilitre to be virtually undetectable. His immune cells have begun to recover so much that he has been able to return to his job as a teacher.

Mr David Reddy, the Roche Pharmaceuticals representative in Barcelona, said that his company had already begun production of T-20 and hoped to have it available by the end of this year. "It is one of the most complex drugs we have ever produced and we have had to build special plants to manufacture it," he said.

T-20 is an important advance, but it still does not erradicate the virus and only prevents it attacking vital cells. Unfortunately T-20 is unsuitable for use in Africa and underdeveloped countries because of price and because patients need to take two injections every day indefinitely.

Meanwhile, AIDS charities urged caution yesterday after a US biotechnology company said a preventive vaccine against HIV/AIDS could be available by 2005 if early trial results were good.

Preliminary findings from the Phase III trials of the vaccine will not be available until early next year but its California-based developer, VaxGen Inc, said it was optimistic.

"I think we will get protection (from the virus) but I don't know what level we will get," Mr Donald Francis, president and co-founder of the company, told an AIDS conference.

Mr Francis said the vaccine used a standard approach and worked in chimpanzees.

"We expect to see in humans what we have seen in animal studies," he said. "If all goes well it could be available by end of 2004 or early 2005."

Hopes for AIDS vaccines have been dashed in the past and AIDS charities said it was still early days for this one.

Additional reporting: Reuters