Pitt Testing Rectal Safety of Promising HIV Prevention Gel in New Trial
PITTSBURGH, Oct. 14, 2010 – Tenofovir gel, a vaginal microbicide that has shown promise for preventing HIV through vaginal sex, is being tested by University of Pittsburgh School of Medicine researchers in a new, multicenter trial looking at its safety and acceptability when used rectally. The study, being led by the U.S. National Institutes of Health (NIH)-funded Microbicide Trials Network (MTN), will help determine if the gel should be evaluated further for its potential to prevent HIV among both men and women who engage in receptive anal intercourse.
While condoms generally are effective for protecting against HIV and other sexually-transmitted infections, most acts of anal sex go unprotected. Moreover, the risk of acquiring HIV through unprotected anal sex is at least 20 times greater than unprotected vaginal sex and increases if other infections are already present in the rectal lining.
Microbicides – substances applied topically on the inside of the rectum or vagina – could potentially help prevent the rectal transmission of HIV, although considerably more research has been conducted looking at microbicides for preventing transmission of HIV through vaginal sex. Tenofovir gel, for example, is a candidate microbicide specifically developed to prevent vaginal transmission of HIV.
The new study, known as MTN-007, comes on the heels of a South African trial that found tenofovir gel significantly reduced the risk of HIV among at-risk women who were instructed to use the gel before and after vaginal sex. In an ongoing, large-scale effectiveness trial called VOICE – Vaginal and Oral Interventions to Control the Epidemic, the MTN is testing daily use of tenofovir gel in African women, with results expected in 2013.
“Although the field is excited about the promise of tenofovir gel as a vaginal microbicide, there is a series of steps that must be taken before we can even consider whether the gel is equally promising for preventing HIV transmitted through receptive anal intercourse,” said Ross Cranston, M.D., FRCP, leader of the Pitt study site and assistant professor of infectious diseases at Pitt School of Medicine. “First, we must determine that it’s safe to use rectally, which is why we are conducting this trial.”
MTN-007 will enroll 60 men and women across three MTN-affiliated U.S. sites: Pitt, the University of Alabama at Birmingham and Fenway Health in Boston. It aims to determine if rectal use of tenofovir gel is safe, and in particular, does not cause cells in the rectum to become more vulnerable to HIV than they already are. The study also will help to understand whether men and women would be willing to use a rectal microbicide. In addition, researchers are hoping to identify biological markers – specific proteins or biochemical activity – that can be used to better assess the potential safety of different candidate microbicides before they are tested in humans.
“While VOICE or other trials may very well prove tenofovir gel is highly effective for preventing vaginal transmission, we need to understand much more about what happens to the cells and tissue when tenofovir gel is used rectally,” said MTN co-principle investigator Ian McGowan, M.D., Ph.D., professor of medicine in the division of gastroenterology, hepatology and nutrition at Pitt School of Medicine and co-principal investigator of the MTN, which is based at Pitt and the Magee-Womens Research Institute.
In the United States alone, receptive anal intercourse is practiced in up to 90 percent of men who have sex with men, according to Chicago-based International Rectal Microbicides Advocates. U.S. estimates and surveys in the United Kingdom indicate that between 10 to 35 percent of heterosexual women have engaged in anal sex at least once. Global estimates suggest 5 to 10 percent of sexually active women are having anal sex. In 2009, there were more than 33 million people living with HIV. The number of new infections continues to outstrip advances in treatment: For every two people who begin treatment, five are newly infected. Men who have sex with men account for at least half of all new infections in the developed world; in the United States, this group represents nearly 60 percent of those newly infected, according to recent reports.
MTN-007 is being funded by the National Institute of Allergy and Infectious Diseases Division of AIDS and the National Institute of Mental Health, both components of the NIH.
To learn more about how to participate in this study, contact research recruiter Anne Davis at (412) 383-1313 or e-mail firstname.lastname@example.org.
About the University of Pittsburgh School of Medicine
As one of the nation’s leading academic centers for biomedical research, the University of Pittsburgh School of Medicine integrates advanced technology with basic science across a broad range of disciplines in a continuous quest to harness the power of new knowledge and improve the human condition. Driven mainly by the School of Medicine and its affiliates, Pitt has ranked among the top 10 recipients of funding from the National Institutes of Health since 1997 and now ranks fifth in the nation, according to NIH data for 2008 (the most recent year for which the data are final).
Likewise, the School of Medicine is equally committed to advancing the quality and strength of its medical and graduate education programs, for which it is recognized as an innovative leader, and to training highly skilled, compassionate clinicians and creative scientists well-equipped to engage in world-class research. The School of Medicine is the academic partner of UPMC, which has collaborated with the University to raise the standard of medical excellence in Pittsburgh and to position health care as a driving force behind the region’s economy. For more information about the School of Medicine, see www.medschool.pitt.edu.
About the Microbicide Trials Network
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.
More information about MTN-007 can be found at http://www.mtnstopshiv.org/news/studies/mtn007.