The New England Journal of Medicine reports that a new HIV prevention method based on a single daily tablet containing two widely used HIV medications has been found to reduce HIV infection risk in uninfected people. The new HIV prevention method, known as pre-exposure prophylaxis (PrEP), reduced HIV infection risk by around 50 percent compared to those study participants who took the placebo.
A total of 2,499 individuals at high risk of HIV infection participated in the six-country study. In all, 64 HIV infections were recorded among the 1,248 study participants who received a placebo pill, while 36 HIV infections were recorded among the 1,251 participants who received the study drug. The average reduction in HIV infection risk of 44 percent includes all study participants - even those who did not take the daily pill consistently.
The researchers say that PrEP was more protective among those who reported taking the pill more regularly. Among participants who used the tablet on 50 percent or more of days, as measured by pill counts, bottle counts and self-reports, risk of HIV infection fell by 50 percent; among those who used the pill on 90 percent or more of days, as determined by the same measures, the PrEP pill reduced infection risk by 73 percent.
The drug used in the study, a single-tablet combination of emtricitabine (FTC 200 mg) and tenofovir (TDF 300 mg), is marketed by Gilead Sciences, Inc. under the brand name Truvada®, and is available generically in many countries at prices as low as approximately 40 cents (U.S.) per tablet in the poorest countries of the world.
Side effects from use of the PrEP pill were mild and infrequent, say the researchers. These included a small number of reports of low-grade transient nausea, which dissipated after several weeks. In addition, isolated mild elevations of creatinine, a naturally occurring molecule filtered by the kidneys, occurred in a small number of individuals receiving the active drug and resolved spontaneously or with discontinuation of the pill.
The researchers say that the findings are a significant advance in HIV prevention. "Thanks to the extraordinary efforts of our study participants, their families and communities, [this study] shows that a preventive drug can significantly reduce HIV infection risk. Further research is now needed to optimize the efficacy of oral PrEP," said Javier R. Lama, co-chair of the study protocol.
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Source: University of California - San Francisco