Poor adherence stopped study of PrEP in women

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The following is a guest blog post by HIV Medicine Association Executive Director, Andrea Weddle, who is live blogging from the 19th Conference on Retroviruses and Opportunistic Infections in Seattle.

Dr. Lut Van Damme presents on the FEM-PrEP trial results at the 19th Conference on Retroviruses and Opportunistic Infections in Seattle Tuesday.

Data presented from the FEM-PrEP trial by Dr. Lut Van Damme Tuesday highlighted the challenge that adherence plays in successfully deploying effective Pre-Exposure Prophylaxis (PrEP) interventions.

The FEM-PrEP study was conducted to evaluate the protective effect of a daily oral dose of emtricitabine/tenofovir disoproxil fumerate (FTC/TDF) among African women, but was halted early, in April 2011. This was due to an interim data analysis showing similar rates of new HIV infections among women taking daily FTC/TDF and the placebo arm – with 33 and 35 HIV infections occurring in both groups respectively.

Self-reported adherence was high (95 percent) in both study groups, with most participants also reporting that taking the daily medication was easy. Pill counts of returned drug also suggested high adherence rates (86 percent). However, monitoring of tenofovir levels in the blood found detectable drug in fewer than 50 percent of infected individuals and uninfected controls – the minimum standard required to evaluate drug effectiveness. Van Damme noted the disparity between the pill counts and drug levels could not be explained by sharing of pills between the active and placebo study arms.

Women in both the active and placebo groups had similar characteristics, with a majority being less than 25 years of age, most reporting low condom use and a majority having a perceived low risk of acquiring HIV infection. Sexually transmitted infection rates also were high in both groups.

FEM-PreP was conducted in South Africa, Kenya and Tanzania and the results reported were based on data from 2,056 women.

A slide from Dr. Van Damme's presentation comparing infected cases and matched controls with detectible drug level in plasma at visits defining infection windows.

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