Toronto

Scientists, governments and funding agencies need to revise their strategy for deploying and testing HIV-prevention methods, delegates to the XVI International AIDS Conference in Toronto, Canada, heard this week.

Although conventional prevention methods, such as the use of condoms, have had some success, advocates say that women need to have more control over prevention. Various new approaches, including the externally applied gels known as microbicides or drugs taken orally, show promise, said leaders in the fight.

Challenges remain, however, in bringing such methods to the clinic. “There are serious obstacles that could significantly delay, or even derail, critical prevention trials — including inadequate resources and capacity to launch and complete trials, and emerging ethical concerns,” warned a group of scientists, doctors and activists called the Global HIV Prevention Working Group.

A 15 August report from the coalition called on governments and scientists to focus on the most promising interventions, set up trial sites, and coordinate their plans to avoid wasting time and money duplicating efforts. It also advised the creation of a panel of experts that could provide ethical guidance for the trials. And it urged societies to prepare for the roll-out of new prevention methods if they prove successful.

The warnings aim to reduce the problems already hampering efforts to find alternative prevention methods. For example, activists' concerns, such as over whether people who contracted HIV during the trial would receive treatment afterwards, shut down two trials on preventive drugs in Cambodia and Cameroon in 2004 and 2005.

Scientists hope that interest from big funding groups, such as the Bill and Melinda Gates Foundation, based in Seattle, Washington, could focus attention on these preventive efforts.

Trials are currently testing the effects on HIV infection of microbicides, orally-ingested drugs, male circumcision, barriers such as diaphragms and the treatment of herpes infections. But the studies are costly and difficult to run.

This year's AIDS conference focused on new preventive methods. Credit: J. UZON/AFP/GETTY

“We need to make strategic choices, and I hope Gates is going to give leadership in the way that is finally happening in the vaccine field,” says Joep Lange, chairman of the International AIDS Society's Industry Liaison Forum.

Trial results can also be complicated when counselling, provided with the trial, cuts the rate of new infections. For instance, the first completed trial of oral prevention drugs, reported at the meeting, tested whether the oral drug tenofovir prevented new infections in 936 women mainly in Ghana. But too few people became infected, so it was difficult to tell whether the drug actually worked, said Leigh Peterson of Family Health International, which conducted the trial with money from the Gates Foundation.

The foundation has already led efforts to coordinate research on a microbicide, and helped write a strategy for microbicide development, due to be released on 17 August. Renee Ridzon, a senior programme officer at the foundation, said it is keenly aware of the need to coordinate prevention trials.

“The field needs to think hard about this,” she said. “It's definitely on our radar screen.”