An outgrowth of post-exposure prophylaxis (or PEP, a short-term antiretroviral treatment that has been used since the early 90s to decrease the likelihood of HIV infection after exposure to the virus, either occupationally or through sex), PrEP is a similar antiretroviral that can be taken by HIV-negative individuals in order to help prevent them from seroconverting (being infected).
The results of a Phase III clinical study known as iPrEx were published in the New England Journal of Medicine on November 23, 2010. The study showed that, in a group of 2,499 gay men, PrEP — in the form of a combination of drugs under the brand name Truvada — was 44 percent effective in preventing HIV seroconversion.
Under the guidance of Dr. Roy Gulick (director of the Weill Cornell Medical College HIV Clinical Trials Unit), a new experiment called the NEXT (Novel Explorations of Therapeutics) PrEP Study will begin this fall. It will include 400 at-risk, HIV-negative gay men, and will take place over 48 weeks at 12 sites across the U.S. and Puerto Rico.
The NEXT PrEP Study will differ from iPrEx in that its primary experimental group will receive a daily regimen of the drug maraviroc (brand name Selzentry). The control group will receive Truvada, and two other experimental groups will receive combinations of maraviroc and either tenofovir or FTC (the two individual drugs that make up Truvada). A major goal of the study, along with testing the HIV-prevention efficacy of maraviroc, will be to gauge the side effects of the drug on participants.