Masaru Goto/ World Bank via Flickr

JOHANNESBURG, SOUTH AFRICA—Nearly four years after political pressure shut down two trials that would have tested whether a once-a-day pill could prevent high-risk HIV-negative people from catching the AIDS-causing virus, there’s a surge of renewed interest in the concept, known as Pre-Exposure Prophylaxis, or PrEP.

Western doctors and organizations that funded the halted trials of the anti-HIV drug tenofovir in Cameroon and Cambodia say they've learned their lesson from the debacle in 2004 and 2005, when activist groups questioned the quality of medical care impoverished study participants would receive if they suffered side effects or the became infected by HIV. Today, with at least seven U.S.-funded PrEP trials underway at a cost of $39.5 million, researchers are working with local advocates, who have traditionally been distrustful of Big Pharma, to push the studies forward.

"The whole prevention community really had a wake-up call," says Linda-Gail Bekker, an infectious disease researcher at the University of Cape Town’s Desmond Tutu HIV Center, who is running the South African study site for a new PrEP trial that will eventually involve at least 3,000 gay men in South Africa, Asia, South America and the U.S. The study, which is enrolling trial participants now, is being funded by the U.S. National Institutes of Health (NIH) and the Bill & Melinda Gates Foundation. Its first results are expected in 2010.

In August 2004, Cambodian Prime Minister Hun Sen stopped a trial of PrEP on prostitutes in his country under pressure from activists who said the study was exploiting vulnerable trial participants. Cameroon, which was to be part of a larger, three-country western Africa PrEP trial, shut the trial there down in early 2005 after questions were raised about the trial’s health care provisions for participants.

PrEP researchers now acknowledge they made a mistake by not involving local advocates from the start. After years of being told that antiretroviral drugs were toxic, the idea of using them in uninfected people seemed reckless to many. Local activists, along with their international supporters, believed the trials were being run by profit-hungry pharmaceutical companies who were coming to poor countries to do dangerous research that would later pad their own pockets and only end up benefiting people in the developed world.

In fact, the trials were being conducted by university and nonprofit researchers, and funded by the U.S. government and the Bill & Melinda Gates Foundation. Gilead Sciences, Inc., tenofovir's maker, provided the drugs for free but was otherwise not involved in the trial. And the drug's safety had already been proved in previous HIV treatment trials—many of them conducted in the U.S.

“I don’t think there was some wild, unethical conduct,” said Mitchell Warren, executive director of the AIDS Vaccine Advocacy Coalition, which has helped facilitate dialogue on PrEP issues. “But there was a little defensiveness and a lot that got lost in translation.”

ACT UP/Paris, which is part of the international AIDS awareness activist coalition and was involved in the Cameroon controversy, and the Treatment Action Campaign (TAC), South Africa's largest organization of people with AIDS, have been involved in new trials from their earliest stages. New guidelines have also been written setting standards for community involvement in prevention trials, which recommend, for example, that researchers hold meetings with communities prior to the beginning of new trials to address what health care will be provided to participants.