Monday, February 18, 2008

(Still) Wanted: A Female-Controlled Method to Prevent HIV

Twenty-seven years after AIDS was first diagnosed among gay men in California and New York, HIV/AIDS has become a health threat borne disproportionately by women in the developing world. Globally, there are twelve HIV-positive women for every ten HIV-positive men. In the hardest hit countries in sub-Saharan Africa, young women are three times more likely than their male peers to become infected.

The disproportionate impact of HIV on women is due to a variety of biological and socioeconomic factors. Many of those factors make today’s HIV prevention options – condoms, mutual monogamy, and male circumcision – inaccessible to women at greatest risk of infection. Many women do not have the social or economic power necessary to insist on condom use and fidelity or to abandon partnerships that put them at risk, and a recent study from Uganda shows that circumcision does not protect female receptive sex partners. There thus is a desperate need to develop new tools to enable women to protect themselves, including microbicides.

This morning, the Population Council posted the results of a phase III effectiveness study of a candidate microbicide called Carraguard, an odorless, clear gel made from carrageenan. Over 6,000 women in South Africa volunteered to be part of this clinical trial, in which participants were randomly assigned to either receive Carraguard or a comparator gel. Trial participants were instructed to use the gel plus condoms every time they had sex, and asked to return to the study clinic repeatedly over a two-year period. During this time, they were provided with condoms and received comprehensive risk reduction counseling, HIV testing, and screening and treatment for STIs.

Unfortunately, trial results showed that the product was safe and acceptable to women, but did not reduce their risk of acquiring HIV.

Twelve other candidate microbicides are currently in human trials, and a new generation of antiretroviral-based products is entering the development pipeline. But developing and testing these compounds is a time- and resource-intensive process, and many policymakers have begun to question whether or not limited public health resources are better used to promote proven prevention technologies like condoms.

This, I believe, is short sighted. For the reasons mentioned above, proven HIV prevention technologies will not protect at-risk women. Furthermore, drug development is always a long term struggle, with dozens of failed products for every one that makes it to market.

As disappointing as these results are, the fact that the trial reached completion is itself a breakthrough. Successful completion of the Carraguard trial is a testament not only to the commitment of the study investigators but also to the dedication of the trial participants themselves.

Regardless of the results, this trial will yield important information about microbicide effectiveness, safety, use, and acceptability, and will help researchers design and test new HIV prevention technologies.

1 comment:

Linda MacDonald Glenn said...

Thanks for posting about this, Sean -- just because it didn't work this time doesn't mean we should give up!