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VOICE HIV prevention trial results indicate importance of adherence

FEM-PrEP study results confirmed; greater attention to adherence will be required in PrEP programs

March 04, 2013

RESEARCH TRIANGLE PARK, NC — FHI 360 and the FEM-PrEP team commend the Microbicide Trials Network and the VOICE (Vaginal and Oral Interventions to Control the Epidemic) trial team for results presented today at the 20th Conference on Retroviruses and Opportunistic Infections (CROI) in Atlanta.

The VOICE study, which began enrolling women in September 2009, was designed to evaluate whether antiretroviral (ARV) drugs commonly used in treating HIV are safe and effective in preventing sexual transmission of HIV in women as either a vaginal gel or an oral tablet used daily, an approach called pre-exposure prophylaxis, or PrEP. VOICE tested three products — tenofovir gel, oral tenofovir and oral Truvada®. While none proved to be effective among the 5,029 women enrolled in the trial, study results showed that most participants did not adhere to the study products daily. Study drug was detected in less than a third of blood samples from women who were assigned to use either Truvada or oral tenofovir and in less than a quarter of samples from women designated to use tenofovir gel. Women who were single and under 25 years of age were least likely to use their assigned product and most likely to acquire HIV.

In 2012, the U.S. Food and Drug Administration (FDA) approved the use of daily, oral Truvada to reduce the risk of sexual acquisition in adults as part of a comprehensive HIV prevention strategy. However, as demonstrated in the FEM-PrEP trial results, which were published in the July 11, 2012 issue of the New England Journal of Medicine (NEJM), the VOICE results reinforce the important role of adherence in HIV prevention studies and the need to find better ways to support adherence in future programs. “Both the VOICE and FEM-PrEP study populations are at very high risk of HIV infection and in great need of new prevention methods. Additional research is needed to determine if the daily use of an oral pill is a feasible option for preventing HIV in African women at high HIV risk,” said Dr. Amy Corneli, lead FEM-PrEP behavioral scientist at FHI 360.

“Results from VOICE and FEM-PrEP are important because they demonstrate that adherence will be a critical factor in HIV prevention science and future PrEP strategies,” said Dr. Tim Mastro, Group Director for Global Health, Population and Nutrition at FHI 360 and co-author on the FEM-PrEP paper published in NEJM in 2012. “We look forward to working with the VOICE team to compare data, given the similarity in populations and findings. Identifying optimal prevention options for all populations will be critical.”

FHI 360 and the FEM-PrEP team remain grateful to the women whose willingness to participate in all of these studies has resulted in a significant contribution to research on HIV prevention methods.

About FEM-PrEP: The FEM-PrEP clinical trial was designed to assess whether HIV-negative women, who are at higher risk of being exposed to HIV, can safely use a daily dose of the antiretroviral (ARV) pill Truvada to help prevent HIV infection. Truvada, which contains the ARVs emticitabine (FTC) and tenofovir disoproxil fumarate (TDF), is approved for treatment of HIV in combination with other ARVs. The study was funded by the U.S. Agency for International Development (USAID), with early funding from the Bill & Melinda Gates Foundation. Gilead Sciences, Inc. provided the study pills.

The FEM-PrEP trial included 2,120 women randomly assigned to take Truvada or a placebo. Thirty-three HIV infections occurred in the Truvada arm and 35 in the placebo arm. Blood plasma drug concentration testing revealed that only 35 percent to 37 percent of uninfected Truvada recipients had evidence of recent trial product use.

About FHI 360: FHI 360 is a nonprofit human development organization dedicated to improving lives in lasting ways by advancing integrated, locally driven solutions. Our staff includes experts in health, education, nutrition, environment, economic development, civil society, gender equality, youth, research, technology, and communication and social marketing — creating a unique mix of capabilities to address today’s interrelated development challenges. FHI 360 serves more than 60 countries and all U.S. states and territories.

From the earliest years of the HIV/AIDS epidemic, FHI 360 has partnered with funders, health ministries and nongovernmental organizations to pioneer HIV research, prevention and treatment programs in the United States and around the world. FHI 360 contributed to groundbreaking research that demonstrated the effectiveness of the antiretroviral drug nevirapine in preventing mother-to-child transmission of HIV. The organization collaborated on the CAPRISA 004 study, demonstrating for the first time that an antiretroviral vaginal gel can decrease HIV acquisition in women by 39 percent. The FEM-PrEP trial of an oral antiretroviral for HIV prevention highlighted the key role of adherence in prevention studies and programs.

FHI 360 also serves as the Coordinating and Operations Center for the HIV Prevention Trials Network (HPTN). The HPTN 052 study recently showed that early antiretroviral treatment of people with HIV dramatically reduces transmission of the virus to their uninfected partners. The treatment reduced the risk of infection to partners by as much as 96 percent. In 2011, Science named the study “Breakthrough of the Year.”

As a member of the Male Circumcision Consortium, FHI 360 is identifying the safest, most effective ways to provide voluntary male circumcision as part of a comprehensive package of HIV prevention services.