Early Treatment with Antiretroviral Therapy Prevents HIV Transmission

A research study led by the University of North Carolina at Chapel Hill has made a major discovery in the effort to halt the spread of HIV, the virus that causes AIDS.

The study results show that early initiation of antiretroviral treatment in people infected with HIV prevents them from transmitting the virus to their partners.

The study, known as HPTN 052, was designed to evaluate whether antiretroviral drugs can prevent sexual transmission of HIV infection among couples in which one partner is HIV-infected and the other is not. The results are the first of their kind from a major randomized clinical trial.

Led by Myron S. Cohen, M.D., of the University of North Carolina, the research found that treating HIV-infected individuals with antiretroviral therapy (ART) when their immune systems are still relatively healthy led to a 96 percent reduction in HIV transmission to their partners.

This critical new finding convincingly demonstrates that early treatment of infected individuals can have a major impact on the spread of the epidemic.

Study investigators enrolled 1,763 couples who were not eligible for ART by WHO standards in nine countries around the world. Couples were randomly assigned to one of two study groups. In the first group, the HIV-infected partner initiated antiretroviral therapy (ART) as soon as the couple enrolled in the study (the immediate treatment group); in the second group, infected partners did not begin ART until their CD4+ counts fell to between 200 and 250 cells/mm3 or they developed an AIDS-related illness (the delayed treatment group). Couples in both groups received HIV primary care, counseling and condoms.

Results of this research study, which was scheduled to conclude in 2015, are being released early, after the independent data and safety monitoring board (DSMB) determined that the benefits of early treatment were clear.

At the time the study was evaluated by the DSMB on April 28, 2011, the available data show that among all couples enrolled in the study, 28 new cases of HIV infection occurred which were linked through genetic analysis to the infected partner enrolled in the study. Of those 28 cases, only one new infection occurred among couples in the immediate treatment group.

This is the first randomized clinical trial to compare starting ART in people with CD4+ counts greater than 350 cells/mm3 with those with CD4+ counts between 200 and 250 cells/mm3.

The results also demonstrated a clinical benefit of early ART, especially in the prevention of a type of tuberculosis infection outside the lungs (extrapulmonary tuberculosis).

Study participants are being informed of the results, and HIV-infected individuals in the delayed treatment arm are being offered ART. The study investigators will continue to monitor participants for at least one more year.