HPTN 052: An update

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Mike Cohen, principal investigator of the remarkable clinical trial that demonstrated “biological and clinical plausibility” that antiretroviral therapy (ART) offers prevention as well as treatment benefits, offered an update to a packed crowd at the annual meeting of the HIV Prevention Trials Network (HPTN).

He began by acknowledging the 13 site teams in nine countries that conducted the study and representatives from the teams stood for applause, while he noted that research to explore the prevention impact of ART had really begun in the early 1990s.

Dr. Cohen then showed a slide with the verbatim message of the Data Safety and Monitoring Board (DSMB) that stopped the trial, noting that neither he nor any of the principals had any idea what the DSMB was up to.

The Board recommends that the results of the trial be announced to the public as soon as possible.

The Board congratulates the team for a very well done trial that definitively shows that immediate ART reduces transmission of HIV.

Cohen briefly summarized the key findings from the trial:

  • Patients on ART reduced their risk of transmitting HIV to their sexual partners by 96.3 percent
  • Immediate ART conferred a clinical benefit for the infected partner
  • CD4 count is not a reliable predictor of the risk of HIV transmission

The study will continue for at least a year, and all HIV-infected participants have been offered access to ART, the majority of who have a CD4 > 350. Investigators hope to look at the durability of the prevention benefit, any clinical events or toxicities, and adherence—which has been extraordinarily high in the trial.  They hypothesize that the addition of an altruistic benefit—keeping their partner negative—has really enhanced adherence.  The median duration of the infected partner on ART is 20 months and the longest is 45 months.

The study raises many questions about the public health impact of treatment, including the special value to discordant couples and the viability of a test and treat strategy. Cohen suggested it would be important to study the impact of combination prevention strategies that include test and treat.  He pointed out that the World Health Organization (WHO) will be releasing new guidance about HIV discordant couples on July 18 which will take into account the results of this study. 

The results of HPTN 052 will appear in a peer-reviewed journal in July, and the results will be presented at the International AIDS Society conference in Rome.  There, the study leaders will offer more detail about the one transmission event in the immediate access to ART arm in the study, and there will also be additional information provided about the clinical benefit of ART to the infected partner.

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