Gilead Sciences says the trial provides the first evidence that the daily tablet offers a new HIV prevention method, known as PrEP (pre-exposure prophylaxis).
The study, a double-blind, placebo controlled Phase III clinical trial, started in 2007 and lasted three years. It involved 2,499 men and transgender women who have sex with men and at high risk of infection. The study took place at 11 sites in the USA, Thailand, South Africa, Brazil, Ecuador and Peru.
Half of the participants received the PrEP tablet while the other half were on a placebo. They all received a broad package of prevention services too, including HIV testing, counseling, infection treatment, and condoms - aimed at minimizing their HIV infection risk.
The trial researchers found that:
- 36 participants on the PrEP tablets became infected with HIV - out of a total of 1,251
- 64 individuals from the placebo group became infected with HIV - out of a total of 1,248
- The average HIV infection risk reduction for those on the PrEP tablets, including participants who sometimes forgot to take their medication, was 43.8%
- Those who took their PrEP tablets at least 50% of the time had a 50.2% lower risk compared to those on the placebo
- Those who took their pill 90% of the time had a 72.8% lower risk of HIV infection
iPrEx Protocol Chair Robert Grant, MD, MPH of the Gladstone Institutes and the University of California at San Francisco, said:
- "The iPrEx study proves that PrEP provides important additional protection against HIV when offered with other prevention methods such as HIV testing, counseling, condom use and management of sexually transmitted infections. As with other prevention methods, the greatest protection comes with consistent use. I hope this finding inspires a renewed commitment from communities, industry and government to stop the spread of HIV."
- "iPrEx is a significant advance in HIV prevention. Thanks to the extraordinary efforts of our study participants, their families and communities, iPrEx shows that a preventive drug can significantly reduce HIV infection risk. Further research is now needed to optimize the efficacy of oral PrEP based on iPrEx results".
- "The devastating impact of HIV continues to spread around the world. Gladstone will continue its research into new ways to prevent HIV infection, and we urge community organizations and governments to make available effective scientific advances to stop HIV such as PrEP."
- "Oral FTC-TDF provided protection against the acquisition of HIV infection among the subjects. Detectable blood levels strongly correlated with the prophylactic effect."
Sources: NEJM, Gilead Sciences, Inc.
"Preexposure Chemoprophylaxis for HIV Prevention in Men Who Have Sex with Men"
Robert M. Grant, M.D., M.P.H., Javier R. Lama, M.D., M.P.H., Peter L. Anderson, Pharm.D., Vanessa McMahan, B.S., Albert Y. Liu, M.D., M.P.H., Lorena Vargas, Pedro Goicochea, M.Sc., Martín Casapía, M.D., M.P.H., Juan Vicente Guanira-Carranza, M.D., M.P.H., Maria E. Ramirez-Cardich, M.D., Orlando Montoya-Herrera, M.Sc., Telmo Fernández, M.D., Valdilea G. Veloso, M.D., Ph.D., Susan P. Buchbinder, M.D., Suwat Chariyalertsak, M.D., Dr.P.H., Mauro Schechter, M.D., Ph.D., Linda-Gail Bekker, M.B., Ch.B., Ph.D., Kenneth H. Mayer, M.D., Esper Georges Kallás, M.D., Ph.D., K. Rivet Amico, Ph.D., Kathleen Mulligan, Ph.D., Lane R. Bushman, B.Chem., Robert J. Hance, A.A., Carmela Ganoza, M.D., Patricia Defechereux, Ph.D., Brian Postle, B.S., Furong Wang, M.D., J. Jeff McConnell, M.A., Jia-Hua Zheng, Ph.D., Jeanny Lee, B.S., James F. Rooney, M.D., Howard S. Jaffe, M.D., Ana I. Martinez, R.Ph., David N. Burns, M.D., M.P.H., and David V. Glidden, Ph.D. for the iPrEx Study Team
NEJM November 23, 2010 (10.1056/NEJMoa1011205)
Written by Christian Nordqvist