Study Finds Daily Pill Helps Prevent HIV in Gay, Bisexual and Transgender Subjects

Study Finds Daily Pill Helps Prevent HIV in Gay, Bisexual and Transgender Subjects

The results from the first Pre-exposure Prophylaxis (PrEP) clinical trial, the iPrEx Study, were just made public and published in today’s issue of the New England Journal of Medicine. In short, the trial showed an overall 44% efficacy in preventing HIV infection in gay, bisexual and transgender subjects who took the daily fixed dose combination antiretroviral pill Truvada (tenofovir [TDF] and emtracitabine [FTC]), compared with participants receiving a placebo. This is the first evidence that oral antiretroviral medications, taken by HIV-negative people before exposure to HIV can reduce the risk of HIV infection. iPrEx is also the first trial showing effectiveness of a new biomedical prevention tool in gay men and other men who have sex with men.

The iPrEx trial enrolled 2,499 participants across 11 sites in six countries---Brazil, Ecuador, Peru, South Africa, Thailand and the United States. It is the first PrEP effectiveness trial to report results. This trial was one of a suite of PrEP trials currently ongoing in a range of populations around the world.

At the end of the three-year trial, there were 36 HIV infections in participants who received Truvada and 64 infections in placebo recipients. Of note, in a sub-analysis, it was found that among those study participants who actually took all of the prescribed doses (as evidenced by adequate blood levels of Truvada), the protective effect was approximately 92%.

The discrepancy between the overall results and the sub-analysis results is due to the fact that clinical trial participants, for any trial, often overstate their compliance. By analyzing blood levels of the drug, the investigators were able to separate out those who were truly compliant and conduct a separate analysis, which showed the higher results.

I’m not overstating when I say that this is FANTASTIC news. Although many of us in the global health field knew that this approach would be successful, it is extremely heartening to have that belief proven so decidedly. Note that this is the first of several trials looking at PrEP to report results. For more information on other PrEP trials, the Global Advocacy for HIV prevention website has some excellent tools and summaries describing this important research. For details download the PrEP trials map, table of ongoing PrEP trials and PrEP trials timeline.

Now the real work begins. Proving efficacy is the first step; getting pills into high-risk people’s mouths is another issue entirely. And it is important to remember that this trial looked at efficacy solely among men who have sex with men. Heterosexual discordant couples, other heterosexuals and injection drug users may have different results. In addition, other studies are underway to determine efficacy of intermittent PrEP, i.e., taking Truvada or other antiretrovirals intermittently when sex is anticipated instead of every day, as well as other antiretroviral combinations. However, we are actively thinking of ways we can incorporate this important prevention intervention into our programming and welcome ideas.

Scott Kellerman, MD, MPH is a Principal Technical Advisor for HIV at Management Sciences for Health.