FOSTER CITY, Calif. — An expert panel at the Food and Drug Administration has recommended that the agency approve a drug made by Gilead Sciences for lowering the risk of infection by the virus that causes AIDS.
The drug maker announced Thursday night that the FDA Antiviral Drugs Advisory Committee had voted to support approval of Truvada (emtricitabine and tenofovir disoproxil fumarate) for pre-exposure prophylaxis, or PrEP, in adults. With PrEP, a person would take the drug every day in order to reduce his or her risk of becoming infected with HIV. Doctors often prescribe the drug for PrEP, but it has yet to win FDA approval for that use. Clinical trials have indicated that the drug is effective in preventing HIV infection through sexual activity, but whether it prevents infection through intravenous drug use remains unclear, and studies of that are ongoing.
The committee's recommendation was based on studies showing that the drug reduced infection risk among men who have sex with men, also known as MSM, by slightly less than 44%, while reducing the risk by between 62% and 73% among men and women at high risk of infection in Botswana and among uninfected partners in Kenyan couples that were serodiscordant, in which one partner is HIV-positive and one is HIV-negative.
The committee voted 19-3 in favor of approval of Truvada for PrEP in MSM; 19-3 with one abstention for preventing infection of uninfected partners in serodiscordant couples; and 12-8 with two abstentions in other people at risk for contracting the virus through sexual activity.
Thursday's vote brings the drug one major step closer to approval for PrEP, and the FDA plans to decide whether or not to approve on June 15; it doesn't bind the FDA to grant approval, but the agency usually follows advisory committee votes.
Still, the practice of using PrEP remains controversial, and many healthcare professionals and AIDS advocates have expressed concerns that widespread use of PrEP could decrease condom use, as well as concerns over adherence to PrEP, with many urging the FDA advisory committee not to recommend approval, according to published reports. A 2010 study conducted by psychology researchers at New York's Hunter College among 180 HIV-negative MSM considered to be at high risk of contracting the disease found that almost 70% reported a willingness to use PrEP if it were at least 80% effective in preventing HIV. But of those, more than 35% said they would be likely to decrease condom use while on PrEP.
The AIDS Healthcare Foundation has also opposed approval of Truvada for PrEP, citing the 44% infection-prevention rate, compared with 98% for condoms while also expressing concerns that its use could lead to drug-resistant HIV strains, while some officials at the Centers for Disease Control and Prevention have said PrEP could create a false sense of security among high-risk groups.
According to market research firm GlobalData, Truvada had sales of $2.88 million in 2011, but with 415,000 Americans identified by the CDC as being at high risk of HIV infection, an FDA approval of the drug for PrEP could increase that figure significantly.