Amazing News! Understanding the Results of CAPRISA 004

The results of CAPRISA 004 provide the first evidence that a vaginal microbicide – specifically, tenofovir gel – can help prevent HIV in women. The study represents an exciting milestone in HIV prevention, but more research is needed to confirm these results and to see if there are ways that tenofovir gel can be made to be even more effective. Research also needs to continue exploring similar approaches involving the use of antiretroviral drugs for HIV prevention.

The CAPRISA 004 study results are to be presented at the International AIDS Conference (AIDS 2010) in Vienna, July 20, and published online by the journal Science the same day.

SUMMARY

• CAPRISA 004 is the first completed effectiveness study of an antiretroviral (ARV)-based prevention approach. ARV-based prevention approaches incorporate some of the same ARV medicines used successfully for treatment of HIV, and the hope is that they will also be safe and effective for HIV prevention. A microbicide is one approach. Another is oral pre-exposure prophylaxis (PrEP), which involves the use of oral ARV tablets There are 11 ongoing trials of ARV-based prevention in different at- risk populations; additional studies are being planned.
• Researchers conducting CAPRISA 004 tested a vaginal microbicide containing the ARV tenofovir to determine whether women at risk of HIV can be protected against infection by following a specific dosing regimen timed before and after sexual intercourse. Tenofovir is a drug that is commonly used as part of a multi-drug regimen to treat HIV in people who are already infected.
• At the end of the study, there were 39 percent fewer HIV infections among women who used tenofovir gel before and after sex than among those who used a placebo gel with no active ingredient, researchers reported at AIDS 2010. These findings provide proof of concept that ARV-based microbicides, in particular tenofovir gel, can help protect women against HIV.
• CAPRISA 004 evaluated tenofovir gel when used in a certain way – before and after sex. The study involved about 900 women from South Africa. Additional studies are needed to test the promise of tenofovir gel in more women and with different dosing strategies . More research is needed to confirm these results in diverse populations of women and to answer additional questions about the safety and effectiveness of tenofovir gel for preventing HIV.
• VOICE– Vaginal and Oral Interventions to Control the Epidemic – is an ongoing study evaluating daily use of tenofovir gel, regardless of when participants have sex. Moreover, VOICE is also testing daily use of two different oral ARV tablets, tenofovir and Truvada®, an important approach to help determine how well each product works compared to its control (placebo gel or placebo tablet) and which approach – gel or tablet – women prefer to use. VOICE will enroll approximately 5,000 women at sites in four countries in southern Africa. About 1,000 women are enrolled in the study so far.
• CAPRISA 004 and VOICE are complementary studies. Each is critical for advancing understanding about the safety and effectiveness of tenofovir gel using different strategies among different populations of African women. Taken together, the studies can provide a much more reliable scientific assessment of tenofovir gel than either alone.

VOICE

• VOICE is a Phase IIb trial designed to evaluate both the safety and effectiveness of two approaches for preventing the sexual transmission of HIV: daily use of an ARV tablet (tenofovir or Truvada) and daily use of an ARV-based gel (tenofovir gel). VOICE is the first effectiveness study of a microbicide that women use every day. It is also the only trial evaluating both a tablet and a gel in the same study, which will help determine which approach women are more likely to use.
• The VOICE Study is being conducted at multiple clinical research sites in South Africa (including the CAPRISA eThekwini site) and at sites in Malawi, Uganda and Zimbabwe. The study began in September 2009 and is expected to be completed in 2012 with results available some time in 2013.
• Women in VOICE are randomized into one of five study groups, either to one of the three tablet groups: tenofovir, Truvada, or oral placebo; or to one of the two gel groups: tenofovir gel or placebo gel. About 5,000 women will be enrolled, 1,000 in each group. Participants use their assigned study product every day for the

There were 39 percent fewer HIV infections in the tenofovir gel group

• VOICE is the flagship study of the Microbicide Trials Network (MTN), an HIV/AIDS clinical trials network established and funded in 2006 by the Division of AIDS (DAIDS) at the National Institute of Allergy and Infectious Diseases (NIAID) with co-funding from the National Institute of Mental Health and the Eunice Kennedy Shriver National Institute of Child Health and Human Development, all components of the U.S. National Institutes of Health (NIH). As co-sponsors of the trial, CONRAD of Arlington, Virginia, USA; and Gilead Sciences, Inc., of Foster City, California, USA, are providing the study products free of charge.

WHY WOMEN NEED HIV PREVENTION METHODS

• Women makeup half of the more than 33million people living with HIV/AIDS worldwide. Insub-Saharan Africa, six of ten new HIV infections in adults happen in women. In several southern African countries, young women aged 15 to 24 are at least three times more likely than their male peers to be infected with HIV .
• Among women, unprotected sex with an infected male partner remains the primary risk factor for HIV infection, and in many parts of the world, heterosexual intercourse is the driving force of the epidemic. Women are twice as likely as their male partners to acquire HIV during sex, due in part to biological factors that make women more vulnerable. Although correct and consistent use of male condoms has been shown to prevent HIV infection, often women do not have a choice if they are used. Women need prevention tools that they can decide to use on their own.

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More information about the VOICE Study can be found at http://www.mtnstopshiv.org/news/studies/mtn003 More information about the results of CAPRISA 004 can be found at http://www.caprisa.org

About the MTN

The Microbicide Trials Network (MTN) is an HIV/AIDS clinical trials network established in 2006 by the National Institute of Allergy and Infectious Diseases (NIAID), part of the U.S. National Institutes of Health (NIH). The MTN brings together international investigators and community and industry partners who are devoted to reducing the sexual transmission of HIV through the development and evaluation of products applied topically or administered orally, working within a unique infrastructure specifically designed to facilitate the research required to support licensure of these products for widespread use.

Based at the University of Pittsburgh and Magee-Womens Research Institute in Pittsburgh, Pennsylvania, USA, MTN’s core operations are supported by a network laboratory at the University of Pittsburgh, a statistical and data management center housed within the Statistical Center for HIV/AIDS Research & Prevention (SCHARP) at the Fred Hutchinson Cancer Research Center, and Family Health International, a global organization with expertise conducting clinical protocols. MTN conducts its trials at clinical research sites located in seven countries and spanning three continents. MTN receives its funding from three NIH institutes: NIAID, the National Institute of Mental Health and the Eunice Kennedy Shriver National Institute of Child Health and Human Development. Among the groups developing and evaluating microbicides for HIV prevention globally, the MTN is the only one funded by NIH.