Can Drugs Prevent HIV?

Center forum explores studies aimed at testing pre-infection interventions

A forum held at the Lesbian, Gay, Bisexual and Transgender Community Center explored the current studies and future potential of using anti-HIV drugs to keep HIV-negative people from becoming infected with the virus that causes AIDS.

“The studies that have been done so far have been done in animals and are based on theoretical models,” said Richard Jefferys, a speaker at the April 25 event, who is director of the basic science, prevention, and vaccines project at the Treatment Action Group (TAG), an AIDS organization. “Obviously, the big question is what will happen in people? What kind of toxicities will we see?”

Currently, there are five studies around the globe that are investigating the use of either tenofovir or truvada for so called pre-exposure prophylaxis (PrEP).

One U.S. study is recruiting 400 gay or bisexual men in Atlanta and San Francisco to take a daily dose of tenofovir or a placebo. The men will participate in the study for 24 months and that could determine the efficacy and safety of the drug.

“We’re not talking about the evening before or the morning after,” said Dr. Albert Liu, a speaker and the director of HIV Prevention Studies at the San Francisco Department of Public Health, a study site. “We’re talking about a continuous dose.”

Investigators also hope to measure if the men can adhere to the daily dosing schedule, weigh any side effects, and determine if they increase their sexual risk-taking as a result of taking the drug.

Another study in Peru will recruit 1,400 gay or bisexual men to take truvada, which a combination of two AIDS drugs, tenofovir and FTC, or a placebo for 20 months. Studies in Ghana, Thailand, and Botswana will recruit 3,200 men and women to take either tenofovir or truvada to determine its safety and efficacy at preventing HIV infection.

The two drugs are manufactured by Gilead Sciences, a California-based pharmaceutical company. Gilead was invited to participate in the forum, but declined. The drugs were selected because they have relatively few side effects and HIV is generally slow to develop resistance to them.

Four earlier PrEP studies in Cambodia, Cameroon, Malawi, and Nigeria were controversial because AIDS activists and political leaders charged that the structure of those studies was unethical and that using those drugs for PrEP might interfere with their use in treating HIV-positive people. While PrEP itself was not deemed objectionable in the earlier efforts, investigators on the current studies are being careful.

“We have learned that we really need political support,” said Pedro Goicochea Vergara, a speaker and co-investigator on the Peru study from the Association on the Impact of Health and Education. The Peru study has the support of that country’s health minister, Vergara said.

Some evidence suggests that sexually active gay men are already using anti-HIV drugs to try to keep from becoming infected with the virus. At least six 2005 articles in the mainstream press referred to this practice.

J. Jeff McConnell, a co-investigator on the Peru study and a project director at the Gladstone Institute of Virology and Immunology at the University of California at San Francisco, noted a 2005 survey of gay men in that city from the federal Centers for Disease Control and Prevention that found that seven percent said they had used an anti-HIV drug as a form of PrEP “at some point in the past.”

Speakers were careful to say that they were not endorsing PrEP even as they said that more research was needed on it.

“We’re definitely not a cheerleader for PrEP,” said Raffi Babakhanian, a speaker and member of the Community HIV/AIDS Mobilization Project (CHAMP). “I don’t think we’re at a point where anybody can be a cheerleader.”

CHAMP was the primary organizer of the event and the Community Center and TAG were among the co-sponsors.

Giving healthy people a drug to prevent them from becoming infected with a bug is rare. People who are traveling to an area where they may be exposed to malaria may take anti-malaria drugs before and during their trip, but that is the only similar practice.

“There isn’t a clear corollary,” said Edd Lee, director of community education and outreach at the AIDS Vaccine Advocacy Coalition (AVAC) and the forum moderator. “That’s why this research is so new.”

Other forum sponsors were AVAC, the Center for HIV Law and Policy, and the Gay Men’s Health Crisis.