The US Food and Drug Administration (FDA) today approved the drug Truvada as a way to reduce the risk of sexually acquired HIV-1 infection. It is the first medication approved to prevent infection in adults who do not have HIV. The drug would be prescribed — along with safer sex practices and regular HIV testing — to people whose partners have HIV and others likely to have sex with infected people.
In a statement, FDA Commissioner Margaret Hamburg called the approval an “important milestone in our fight against HIV”, adding that 50,000 people in the United States are diagnosed with HIV infection each year, despite the availability of effective prevention strategies.
As part of the approval process, the FDA reviewed the results of two large, randomized trials showing that Truvada could be used to prevent infection. One enrolled 2,499 men or transgender women who do not have HIV, have sex with men and are likely to engage in risky sexual behaviour. That study showed that Truvada reduced risk of HIV infection by 42% compared with placebo. The other trial enrolled 4,758 heterosexual couples in which only one partner was infected. In that trial, infection risk in participants taking Truvada was reduced by 75%.
The benefits and risks of the drug were considered by an FDA committee earlier this year. A chief concern was that people taking the drug to prevent infection would not take it every day and so would develop resistance to Truvada as a therapy if they became infected. (In fact, 6 of 11 clinical participants who tested negative before trials began but positive several weeks later were told that Truvada could not be used to treat their infection.)
When approving the drug, FDA officials also required Truvada’s manufacturer, Gilead Sciences, based in Foster City, California, to collect samples from individuals who become infected while taking the drug and look for signs of resistance. Gilead also developed an FDA-approved education strategy for health-care providers and uninfected individuals. It has also pledged to offer free condoms (used consistently, condoms are better than Truvada in reducing HIV transmission) as well as vouchers for HIV testing.
Truvada was approved in 2004 to treat people already infected with HIV in combination with other drugs, and it is now the most prescribed HIV drug in the United States, according to a statement from Gilead. It is a combination of two drugs that interfere with the enzyme reverse transcriptase, which converts viral RNA into DNA, an essential step in HIV reproduction.