April 25th, 2011

FEM-PrEP: A Set Back in HIV Prevention Research

HIV prevention has been on such a roll recently that the recent negative news from the FEM-PrEP study came as something of a surprise.  Bottom line:

Following a scheduled interim review of the FEM-PrEP study data, the Independent Data Monitoring Committee (IDMC) advised that the FEM-PrEP study will be highly unlikely to be able to demonstrate the effectiveness of Truvada [emtricitabine (FTC) and tenofovir disoproxil fumarate (TDF)] in preventing HIV infection in the study population, even if it continued to its originally planned conclusion. FHI subsequently concurred and has therefore decided to initiate an orderly closure of the study over the next few months.

When studies are stopped early by a data and safety monitoring board, the investigators are of course as taken by surprise as the rest of us, and hence lots of details from this study are still not available.

As a result,  we can only speculate why TDF/FTC (Truvada) worked for prevention of HIV among gay men, but not among heterosexual women.  Some (unofficial) thoughts thoughts from my friend/colleague Raphy Landovitz, who does research in HIV prevention:

I’m willing to bet it all comes down to adherence, with the proof to come in the drug-level analyses.  As iPrEx showed, self report of 95% in both arms is meaningless.  One also wonders if there was more condom non-adherence as part of fertility goals.

Regardless of the cause, these negative results underscore one of the most important specific items in the CDC “Guidance” on use of PrEP:  that for now, if it’s prescribed, the only appropriate recipients are high-risk MSM.

[Edit:  Nice summary of the FEM-PrEP study findings and implications over here in Journal Watch HIV/AIDS Clinical Care.]

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HIV Information: Author Paul Sax, M.D.

Paul E. Sax, MD

Contributing Editor

NEJM Journal Watch
Infectious Diseases

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