Aids prevention pill study halted

2011-04-19 09:27

Atlanta - Researchers are stopping a study that tests a daily pill to prevent infection with the Aids virus in thousands of African women because partial results show no signs that the drug is doing any good.

Women taking Truvada, made by Gilead Sciences Inc, are just as likely to get HIV as other women who have been given dummy pills, an interim analysis of the study found.

Even if the study were to continue, it would not be able to determine whether the pills help prevent infection, since the results are even this far along, researchers said.

The finding is disappointing because another study last year concluded that Truvada did help prevent infections in gay and bisexual men when given with condoms, counseling and other prevention services.

Many Aids experts view that as a breakthrough that might help slow the epidemic.

Family Health International, a nonprofit involved in Aids research, announced the new results on Monday.

The group launched the study two years ago and had enrolled about half of the 3 900 women intended in Kenya, Tanzania and South Africa.
As of last week, 56 new HIV infections had occurred, half in each group.

No safety problems were seen with Truvada, but women taking it were more likely to become pregnant than those on dummy pills.

Dr. Timothy Mastro of Family Health International said: "That's both a surprising finding and one that we can't readily explain".

The study was sponsored by the US Agency for International Development and the Bill & Melinda Gates Foundation.

Gilead provided the drugs for the study.

Truvada is already being sold for treating HIV. It's a combination of two drugs, tenofovir and emtricitabine, or FTC, made by California-based Gilead Sciences Inc.

Using it or its components for prevention is still "very promising," Mastro said, although benefits and risks may vary by gender and by the way the virus is spread - sex between men and women or riskier anal sex among men, for example.

Last year, a study in South Africa found that a vaginal gel spiked with tenofovir cut in half a woman's chances of getting HIV from an infected partner.

Protection was greater for those who used it most faithfully.

A similar effect was seen in the study of Truvada in gay men. The drug lowered the chances of infection by 44% and by 73% or more among men who took their pills most faithfully.

The US Centres for Disease Control and Prevention recently gave advice to doctors on prescribing Truvada along with other prevention services for gay men, based on those encouraging results.