Infectious Disease · 2011
HPTN 052: Antiretroviral Therapy as HIV Prevention
HIV Prevention Trials Network 052
In the years before HPTN 052, HIV treatment guidelines were largely written from the perspective of the infected individual. The central question was when to start antiretroviral therapy in a person with HIV, and the answer hinged on CD4 count thresholds and the risk of opportunistic infection. That treatment might simultaneously protect an uninfected sexual partner was a compelling hypothesis, but it lacked randomized evidence to move policy.
HPTN 052 was designed to test that hypothesis directly. The trial enrolled 1,763 serodiscordant couples across 13 sites in nine countries, including Malawi, Zimbabwe, India, Brazil, and the United States. The HIV-positive partner was randomly assigned to start antiretroviral therapy immediately or to defer until CD4 count fell below 250 cells per cubic millimeter or clinical disease developed. Myron Cohen at the University of North Carolina at Chapel Hill led the study, and Marybeth McCauley coordinated its multinational operations.
Over the follow-up period, only one linked HIV transmission occurred in the immediate-treatment group, compared with 27 in the deferred group, a 96% reduction. The finding was so decisive that the independent data and safety monitoring board recommended unblinding the trial early and offering therapy to all deferred-arm participants. The result was named Science magazine's Breakthrough of the Year in 2011.
The public health implications extended beyond the individual couple. Treatment-as-prevention meant that expanding access to antiretroviral therapy was not only a clinical priority but a prevention strategy at the population level. The concept, already theorized in models by Julio Montaner and colleagues, now had direct trial support. Before HPTN 052, treatment timing guidelines focused on protecting the person with HIV; afterward, they had to account for community transmission as well.
The World Health Organization cited HPTN 052 among the key evidence for its 2015 recommendation to treat all persons with HIV at diagnosis, regardless of CD4 count. The policy, known as Treat All, was adopted widely in national guidelines. By reframing antiretroviral therapy as both treatment and prevention, the trial gave public health programs a new argument for funding treatment access in high-burden countries.
Key People
- Myron Cohen — Principal investigator; led the HPTN 052 trial design and execution.
- Marybeth McCauley — Protocol coordinator; managed multinational trial operations.
- Julio Montaner — Modeled treatment-as-prevention concept that HPTN 052 confirmed empirically.
N Engl J Med. 2011;365(6):493-505
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