Women are focus of VOICE Study testing both a vaginal gel and ARV tablets
CAPE TOWN, SOUTH AFRICA, JULY 20, 2009 – A large-scale clinical trial looking to prevent HIV infection in women, an especially vulnerable population in sub-Saharan Africa, is expected to launch in Zimbabwe next month, say researchers from the Microbicide Trials Network (MTN) who are leading the study.
The VOICE Study — Vaginal and Oral Interventions to Control the Epidemic — will help determine whether some of the same antiretroviral (ARV) medications used to treat HIV can also be used to prevent it when they are given as a vaginal microbicide gel or as an oral tablet taken once a day, an approach called pre-exposure prophylaxis (PrEP). VOICE is the first HIV prevention trial that will evaluate two different approaches in the same study and the first effectiveness trial of a microbicide in which women will use the gel every day instead of only at the time of sex. The U.S. National Institutes of Health is funding the study.
Nearly 5,000 women will be enrolled in VOICE, which will take about three and a half years to complete with results expected in 2012. Three sites in
VOICE will also be conducted in
Women represent nearly 60 percent of adults living with HIV in sub-Saharan
“ARVs have made a tremendous difference in the treatment of HIV, and we have a good indication of their potential in the prevention arena as well. What’s unique about VOICE is that we’ll be able to evaluate two different ARV-based prevention approaches, each with great promise as a method for preventing the sexual transmission of HIV in women. Women throughout the world, but especially here in Africa, stand to benefit if we find either one is safe and effective,” said Mike Chirenje, M.D., associate professor and consultant gynecologist in the department of obstetrics and gynecology at the University of Zimbabwe in Harare and co-chair of the VOICE Study.
Two ARV tablets are being tested in VOICE: tenofovir and Truvada.® Tenofovir, short for tenofovir disoproxil fumarate (TDF), is also known by the brand name Viread®, while Truvada is the brand name for a combination drug that contains tenofovir and another active ingredient called emtricitabine (FTC). Both are approved for treating HIV as part of antiretroviral therapy (ART). While at least three ARVs are typically used for ART, a single ARV tablet taken once a day is the regimen being tested for HIV prevention in current PrEP trials, including VOICE.
The vaginal microbicide being evaluated in VOICE, tenofovir topical gel, contains the activated form of the same ingredient in the oral tablet. It is among a newer class of candidate microbicides – substances intended to reduce or prevent the sexual transmission of HIV and other sexually transmitted infections when applied topically inside the vagina or rectum – with specific activity against HIV.
Women in VOICE will be randomly assigned to one of five study groups. Two groups will apply gel every day – either tenofovir gel or a placebo gel with no active ingredient. Three groups will be assigned to daily tablet regimens, with either tenofovir, Truvada or a placebo tablet as the drug under study. Because the study is blinded, neither the participants nor the researchers will know who is in which gel or tablet group. Women will use the same product every day the entire time they are in the study, which is expected to be an average of 22.5 months. All participants will receive ongoing HIV risk-reduction counseling, condoms, and diagnosis and treatment of sexually transmitted infections (STIs).
To determine the approach that women are more likely to use consistently, researchers will ask participants a series of standard questions about sexual activity, product use, product use adherence, male condom use and product sharing. Participants will also answer the same kinds of questions privately with the help of a computer, an approach that is thought to be a better way to collect information about sensitive behaviors.
“We’re focusing this research in a part of the world where it really needs to work, but for any approach to be truly effective, women have to use it. So, a major question that we will also address in VOICE is which of the two – the tablet or the gel – will women actually be more inclined to use,” said Jeanne Marrazzo, M.D., M.P.H., associate professor of medicine in the division of allergy and infectious diseases at the University of Washington in Seattle, U.S.A., and VOICE Study co-chair with Dr. Chirenje.
VOICE researchers also plan to conduct a companion study at RHRU’s Tshireletso Clinic in
Including VOICE, there are seven ongoing trials of oral PrEP in different at-risk populations. Some of these are being conducted in
One other trial is evaluating tenofovir gel. Unlike VOICE, this study, called CAPRISA 004, is testing a regimen in which women insert gel before and after sexual intercourse.
Earlier this year, researchers from the MTN reported the results of a study called HPTN 035 showing that a microbicide called PRO 2000 gel was 30 percent effective. Although this fell short of statistical significance, the results demonstrated for the first time the promise of a vaginal microbicide for preventing HIV in women. Results of a larger study of PRO 2000 sponsored by the Medical Research Council and the Department for International Development of the
“VOICE is entering the HIV prevention landscape at a time of renewed hope and optimism. Could tenofovir gel or oral PrEP be powerful tools that will slow the rate of new infections? We think so. There is no magic bullet, but both gel and tablets could make a difference in the lives of people by helping to prevent women from getting infected,” commented Sharon Hillier, Ph.D., vice chairman and professor, department of obstetrics and gynecology and reproductive sciences at the University of Pittsburgh School of Medicine, and MTN principal investigator.
The VOICE Study is being funded by the National Institute of Allergy and Infectious Diseases (NIAID) with co-funding from the Eunice Kennedy Shriver National Institute of Child Health and Human Development and the National Institute of Mental Health, all components of the U.S. National Institutes of Health.
Truvada and the oral and topical formulations of tenofovir were developed by Gilead Sciences, Inc., of
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More information about the VOICE Study can be found at http://www.mtnstopshiv.org/news/studies/mtn003
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 with co-funding from the Eunice Kennedy Shriver National Institute of Child Health and Human Development and the National Institute of Mental Health, all components of the U.S. National Institutes of Health. Based at Magee-Womens Research Institute and the University of Pittsburgh, the MTN brings together international investigators and community and industry partners who are devoted to preventing or reducing the sexual transmission of HIV through the development and evaluation of products applied topically to mucosal surfaces or administered orally.