Early initiation of antiretroviral treatment
in people infected with HIV prevents them from transmitting the virus to their
partners, according to findings released Thursday from a large-scale
international clinical study.

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 Cohen, 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.
All couples were at least 18 years of age. The vast majority of the couples (97
percent) were heterosexual, which precludes any definitive conclusions about
effectiveness in men who have sex with men.

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.

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).

“We want to thank the study participants for
making such an important contribution in the fight against HIV/AIDS. We think
that these results will be important to help improve both HIV treatment and
prevention,” Cohen said in a statement.

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.

The research was conducted by the HIV Prevention
Trials Network, which is largely funded by the U.S. National Institute of
Allergy and Infectious Diseases.

“Previous data about the potential value of
antiretrovirals in making HIV-infected individuals less infectious to their
sexual partners came largely from observational and epidemiological studies,”
said NIAID Director Anthony S. Fauci in a statement. ” This new finding
convincingly demonstrates that treating the infected individual — and doing so
sooner rather than later — can have a major impact on reducing HIV
transmission.”

VietNamNet/Xinhuanet