A Pill a Day Keeps HIV Away

HIV infection continues to extract a devastating toll on the fabric of society, increasing disability and death during the economically productive years of young adult life. The number of new cases of HIV continues to grow, with high-risk populations facing a 3 to 5% annual risk of acquiring HIV infection. New prevention strategies are urgently needed to curb the spread of HIV infection. Antiretroviral therapy (ART) for HIV treatment acts by preventing the replication of the virus in the body, which is a necessary step for HIV to establish infection. Could taking ART prophylactically prevent the acquisition of HIV among at risk individuals not infected with the virus? In several landmark papers in the New England Journal of Medicine , researchers demonstrate the efficacy of this approach, which is known as pre-exposure prophylaxis (PrEP). Baeten and colleagues followed 4747 couples in Uganda and Kenya among whom one partner was HIV-positive and the other was HIV-negative. In the two intervention arms of the PrEP protocol, the HIV-negative partner received PrEP and the results were compared with HIV-negative participants who did not take PrEP. Two types of ART were included in the trial: tenofovir and coformulated tenofovir-emtricitabine, which reduced the occurrence of HIV infection by 67 and 75%, respectively. Similarly, Thigpen and colleagues reported the results of their PrEP trial, which followed 1219 HIV-negative men and women in Botswana. These authors found that tenofovir-emtricitabine reduced the incidence of HIV infection by 62%. A third study by Van Damme and colleagues, which followed 2120 HIV-negative women in Kenya, South Africa, and Tanzania, did not find the same results. In this study, tenofovir-emtricitabine did not prevent HIV acquisition. Data on PrEP adherence demonstrated that PrEP must be taken daily to prevent HIV infection and that the failure of PrEP in this study was associated with low blood levels of active drug. In all three studies, participants received HIV prevention counseling and condoms, and HIV-positive participants received ART if eligible. The studies found that PrEP was safe and well tolerated. These studies are good news for HIV prevention for which effective tools are needed worldwide. Given the strength of the evidence, the U.S. Food and Drug Administration (FDA) recently approved PrEP for use among high-risk uninfected individuals in the United States. However, there will be programmatic, logistic, and resource challenges in order to roll out PrEP, including how to support PrEP adherence. Although we should not underestimate the work that lies ahead, we can be relieved to have a potentially highly efficacious tool for HIV prevention. J. M. Baeten et al. , Antiretroviral prophylaxis for HIV prevention in heterosexual men and women. N. Engl. J. Med. , 11 July 2012 (10.1056/NEJMoa1108524). [[Full Text]][1] M. C. Thigpen et al. , Antiretroviral preexposure prophylaxis for heterosexual HIV transmission in Botswana. N. Engl. J. Med. , 11 July 2012 (10.1056/NEJMoa1110711). [[Full Text]][2] L. Van Damme et al. , Preexposure prophylaxis for HIV infection among African women. N. Engl. J. Med. , 11 July 2012 (10.1056/NEJMoa1202614). [[Full Text]][3] [1]: http://www.nejm.org/doi/full/10.1056/NEJMoa1108524 [2]: http://www.nejm.org/doi/full/10.1056/NEJMoa1110711 [3]: http://www.nejm.org/doi/full/10.1056/NEJMoa1202614