The journal Science has chosen the HPTN 052 clinical trial, an international HIV prevention trial sponsored by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, as the 2011 Breakthrough of the Year. The study found that if HIV-infected heterosexual individuals begin taking antiretroviral medicines when their immune systems are relatively healthy as opposed to delaying therapy until the disease has advanced, they are 96 percent less likely to transmit the virus to their uninfected partners. Findings from the trial, first announced in May, were published in the New England Journal of Medicine in August. The complete top 10 list of 2011 scientific breakthroughs appears in the Dec. 23, 2011, issue of Science.

“The HPTN 052 study convincingly demonstrated that antiretroviral medications can not only treat but also prevent the transmission of HIV infection among heterosexual individuals,” said NIAID Director Anthony S. Fauci, M.D. “We are pleased that Science recognized the extraordinary public health significance of these study results. This recognition also is a credit to the hard work and dedication of the HPTN 052 researchers and the more than 3,000 study participants who selflessly gave their time and energy to make such a significant contribution to the fight against HIV/AIDS.”

Led by study chair Myron Cohen, M.D., director of the Institute for Global Health and Infectious Diseases at the University of North Carolina at Chapel Hill, HPTN 052 began in 2005 and enrolled 1,763 heterosexual couples in Botswana, Brazil, India, Kenya, Malawi, South Africa, Thailand, the United States and Zimbabwe. Each couple included one partner with HIV infection. The investigators randomly assigned each couple to either one of two study groups. In the first group, the HIV-infected partner immediately began taking a combination of three antiretroviral drugs. The participants infected with HIV were extensively counseled on the need to consistently take the medications as directed. Outstanding compliance resulted in the nearly complete suppression of HIV in the blood (viral load) of the treated study participants in group one.

In the second group (the deferred group), the HIV-infected partners began antiretroviral therapy when their CD4+ T-cell levels - a key measure of immune system health—fell below 250 cells per cubic millimeter or an AIDS-related event occurred. The HIV-infected participants also were counseled on the need to strictly adhere to the treatment regimen.

The study was slated to end in 2015, but an interim data review in May by an independent data and safety monitoring board (DSMB) found that of the total 28 cases of HIV infection among the previously uninfected partners, only one case occurred among those couples where the HIV-infected partner began immediate antiretroviral therapy. The DSMB, therefore, called for immediate public release of the study’s findings.

The magnitude of protection against HIV infection demonstrated in HPTN 052 has made the successful strategy of the clinical trial a key component of public health policies recently discussed by federal officials and others saying that achieving an end to the HIV/AIDS pandemic is now feasible with additional research and implementation efforts.

“On its own, treatment as prevention is not going to solve the global HIV/AIDS problem,” said Dr. Fauci. “Yet when used in combination with other HIV prevention methods—such as knowing one’s HIV status through routine testing, proper and consistent condom use, behavioral modification, needle and syringe exchange programs for injection drug users, voluntary, medically supervised adult male circumcision, preventing mother-to-child transmission, and, under some circumstances, antiretroviral use among HIV-negative individuals—we now have a remarkable collection of public health tools that can make a significant impact on the HIV/AIDS pandemic.”

“Scale-up of these proven prevention methods combined with continued research toward a preventive HIV vaccine and female-controlled HIV prevention tools places us on a path to achieving something previously unimaginable: an AIDS-free generation,” Dr. Fauci added.

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HPTN 052 was conducted by the HIV Prevention Trials Network, which is largely funded by NIAID with additional funding from the National Institute on Drug Abuse and the National Institute of Mental Health, both part of the NIH.

NIAID conducts and supports research - at NIH, throughout the United States, and worldwide - to study the causes of infectious and immune-mediated diseases, and to develop better means of preventing, diagnosing and treating these illnesses.

About the National Institutes of Health (NIH): NIH, the nation’s medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases.

References: J. Cohen. Breakthrough of the Year: HIV Treatment as Prevention. Science Vol. 34, Dec. 23, 2011, 1628-1629.

M.S. Cohen et al. Prevention of HIV-1 Infection with Early Antiretroviral Therapy. New England Journal of Medicine DOI: 10.1056/NEJMoa1105243 (2011).