New York, 18 April 2011 – At a scheduled, interim data review, the Independent Data Monitoring Committee (IDMC) for the FEM-PrEP study of oral pre-exposure prophylaxis (PrEP) using daily TDF/FTC (brand-name Truvada) determined that the trial would not be able to answer the question of whether the study drug decreased risk of HIV infection among HIV-negative women at risk via sexual transmission. The IDMC has, therefore, recommended that the study be discontinued.
“Today’s announcement about the FEM-PrEP study is disappointing,” said Mitchell Warren, AVAC executive director. “However, it must be seen as what it is – the closure of a single trial in a field that has generated exciting results in the recent past. Even with this finding, there is still a strong rationale for continuing other trials, including those in women, in hopes of obtaining better results in the future.”
The FEM-PrEP trial tested the same drug and daily dosage of TDF/FTC (also known as Truvada) as the landmark iPrEx PrEP trial among gay and bisexual men and transgender women. Last November, results of the iPrEx trial showed a 44 percent reduction in HIV risk overall in participants who received TDF/FTC compared to those who received the placebo. In July 2010, results of the CAPRISA 004 study showed a 39 percent reduction in HIV risk among women who used a 1% tenofovir gel microbicide compared to those who received a placebo gel. In both trials, there was evidence that adherence matters – that participants who used the intervention most consistently had the highest levels of protection.
Two other ongoing trials in sub-Saharan Africa are evaluating oral TDF/FTC and/or TDF alone among heterosexuals. The VOICE trial is evaluating oral TDF and TDF/FTC as well as 1% tenofovir gel in 5,000 women in sub-Saharan Africa. Partners PrEP is evaluating oral TDF and TDF/FTC in the HIV-negative member of couples in which one partner is HIV-infected.
“The premature closing from FEM-PrEP does not predict the findings from either VOICE or Partners PrEP,” Warren said. “It is too soon to tell whether the differences observed between iPrEx and FEM-PrEP are due to the route of exposure, pill-taking behavior, biological differences in drug activity, or some other factor. Along with further analysis of FEM-PrEP data, VOICE, Partners PrEP and other ongoing trials will add critical pieces to the puzzle of if and how to deploy PrEP as an effective prevention tool.”
“We commend the FEM-PrEP trial team, the members of the IDMC and especially the nearly 2,000 women who participated in the trial. Despite the inability of the trial to answer the question of whether TDF/FTC reduces women’s risk of HIV infection, FEM-PrEP has provided and will continue to provide key information that will help move the PrEP research agenda forward,” Warren said.
Further analysis of the FEM-PrEP data will provide a better of understanding of the observation that there was a higher pregnancy rate among women in the active drug arm of the trial, compared to those in placebo arm.
In addition to VOICE and Partners PrEP, there is an ongoing PrEP efficacy trial among injection drug users and a soon-to-be-launched follow-on to iPrEx known as the iPrEx Open Label Extension study, or iPrEx OLE. There are still close to 20,000 participants involved in PrEP trials around the world.
“Medical research is often complicated, and we must expect setbacks along the way. But with 2.6 million new HIV infections every year, it is imperative that we continue to look for new ways to curb the epidemic,” Warren added. “The success of the iPrEx and the CAPRISA 004 trials have shown the promise of ARV- based prevention options as part of a comprehensive prevention package that includes condoms behavioral counseling and treatment of other sexually transmitted diseases. There will never be a silver bullet for HIV prevention, so we must continue to seek a variety of new options to protect those at risk through different routes of transmission and throughout their lives.”
More information about ongoing PrEP research is available at avac.org/prep.
About AVAC: Founded in 1995, AVAC is an international non-profit organization that uses education, policy analysis, advocacy, and community mobilization to accelerate the ethical development and eventual global delivery of AIDS vaccines and other new HIV prevention options as part of a comprehensive response to the pandemic.