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Initiation of antiretroviral treatment protects uninfected sexual partners from HIV infection

FHI statement on HPTN 052

May 12, 2011

Men and women infected with HIV reduced the risk of transmitting the virus to their sexual partners by 96 percent through early initiation of oral antiretroviral therapy (ART), according to findings from a large-scale multinational clinical study conducted by the HIV Prevention Trials Network (HPTN).

The clinical trial, known as HPTN 052, was designed to evaluate whether early antiretroviral use by an HIV-infected individual would reduce transmission of HIV to an HIV-uninfected partner and potentially benefit the HIV-infected individual as well. The trial is the first randomized clinical trial to show that treating an HIV-infected individual with ART can reduce the risk of sexual transmission of HIV to an uninfected partner.

HPTN is a global partnership dedicated to reducing the transmission of HIV through cutting-edge biomedical, behavioral, and structural interventions, largely funded by National Institute for Allergy and Infectious Diseases with additional funding from National Institute on Drug Abuse and National Institute for Mental Health, at the US National Institutes of Health. FHI serves as the coordinating and operations center for HPTN. As the operations center, FHI is responsible for the scientific management of HPTN and facilitates and participates in HPTN leadership, scientific working groups, protocol teams, and the community engagement program.

"FHI is proud of our role as the Operations Center for HPTN in facilitating the HPTN 052 study," said Dr. Ward Cates, President, Research at FHI and member of the leadership of HPTN. "Treating infected individuals prevents transmission to their uninfected partner and benefits the individual. Armed with these findings, FHI can continue to contribute to the informed care and treatment and prevention of HIV through our global programs and intramural research."

HPTN 052 began in April 2005 and enrolled 1,763 HIV-serodiscordant couples at 13 sites across Africa, Asia and the Americas, the vast majority of which (97 percent) were heterosexual. An HIV-serodiscordant couple has one member who is HIV-infected and the other who is HIV-uninfected. In the study, the HIV-infected partner was required to have a CD4+ cell count (T cells) between 350-550 cells/mm3 at enrollment, and therefore did not require HIV treatment for his or her own health.

The investigators randomly assigned the couples to one of two study groups. In one group, the HIV infected partner immediately began taking a combination of three antiretroviral drugs upon study enrollment. In the other group, the HIV-infected partners began ART when their CD4 counts fell below 250 cells per cubic millimeter (cells/mm³) or an AIDS-related event occurred.

Throughout the study, both groups received HIV-related care that included counseling on safe sex practices, free condoms, treatment for sexually transmitted infections, regular HIV testing, and frequent evaluation and treatment for any complications related to HIV infection. Each group received the same amount of care and counseling. In addition, individuals who become HIV-infected during the course of the study are referred to local services for appropriate medical care and treatment.

The trial was slated to end in 2015; however, the independent Data and Safety Monitoring Board (DSMB) recommended that the results be released as soon as possible. The DSMB concluded that it was clear that early initiation of ART by HIV-infected individuals with relatively healthy immune systems substantially protects partners from infection, with a 96 percent reduction in HIV transmission.

Study participants are being informed of the results. The study investigators will continue following the study participants for at least one year.

"This is excellent news," said Dr. Myron Cohen, HPTN 052 Principal Investigator and Associate Vice Chancellor for Global Health and Director of the Institute of Global Health and Infectious Diseases at the University of North Carolina at Chapel Hill. "The study was designed to evaluate the benefit to the sexual partner as well as the benefit to the HIV-infected person. This is the first large randomized clinical trial to definitively indicate that an HIV-infected individual can reduce sexual transmission of HIV to an uninfected partner by beginning antiretroviral therapy sooner. HPTN recognizes the significant contribution that this study's participants have made to furthering the progress in HIV treatment and prevention. We are very grateful for their participation."