Study: Gilead’s Truvada provides protection against the acquisition of HIV infection

Gilead’s once-daily combination treatment Truvada (tenofovir/emtricitabine) reduced the risk of contracting HIV in high-risk men compared to placebo, according to study results published Tuesday in the NEJM. The trial is the first to show that taking a drug before infection with the virus can reduce the risk of HIV transmission, the researchers said. Cate Hankins, chief scientific officer of the Joint United Nations Programme on HIV/AIDS, commented that although the findings “show that this concept works,” the result was “a little lower than what we had hoped for, but nonetheless very encouraging.”

The study randomised 2499 HIV-negative men or transgender women who have sex with men and who were at high risk of contracting the virus to receive daily treatment with Truvada or placebo. After a median follow-up of 1.2 years, researchers found that 100 people became infected with HIV, including 36 in the Truvada arm of the trial, and 64 in the placebo arm. “This means that the daily use of Truvada reduced the risk of HIV acquisition by 43.8 percent,” noted Anthony Fauci, director of the US National Institute of Allergy and Infectious Diseases, which funded the study.

Data also showed that among those that had active drug in their blood 90 percent of the time, their risk of contracting HIV was lowered by 73 percent compared to placebo. People who took Truvada and became infected with HIV had either very low levels of the drug in their blood or none at all, the researchers said. “We think the best explanation for why the drug was not in the body is that the people were not taking it,” commented lead researcher Robert Grant.

Fauci noted that the study also demonstrated that Truvada was safe, with only mild side effects reported, and remained effective against the virus. Researchers plan to launch further studies to evaluate whether the same approach with Truvada could prevent infections among heterosexuals and drug users.

Some physicians are already prescribing Truvada off-label to prevent HIV infection, Fauci indicated. However, Howard Jaffe, president of Gilead’s non-profit charity, said he doesn’t expect the study’s results to immediately fuel demand for Truvada and that the company wasn’t sure if Gilead would seek permission from regulators to market the drug for such use. Sanford C. Bernstein analyst Geoffrey Porges said the use of Truvada for prevention “does not represent a significant commercial opportunity” for Gilead. The drug, which is approved for the treatment of HIV, had annual sales of $2.5 billion last year.