Emma Hitt, PhD
June 11, 2012 — The US Food and Drug Administration (FDA) has delayed its decision on allowing the use of tenofovir disoproxil fumarate/emtricitabine (Truvada, Gilead) as preexposure prophylaxis (PrEP) so that the proposed risk evaluation and mitigation strategy (REMS) can be reviewed.
In early May, the FDA's Antiviral Drugs Advisory Committee strongly backed approval of the first-ever drug for the prevention of sexually acquired HIV-1 infection.
However, concerns by the panel at the time included that people may neglect condom use if they feel they are protected by PrEP. Panelists were also concerned that uninfected people taking PrEP who become infected with HIV may not switch to a 3-drug regimen as recommended.
According to the company, the FDA has postponed the target date to September 14 so it can review Gilead's REMS plan to help ensure that patients will not misuse the drug.
The committee's recommendation for supplemental approval of tenofovir/emtricitabine for PrEP is based on the findings of 3 large randomized controlled clinical trials in men who have sex with men and transgender women (iPrEx) and in heterosexual men and women (Partners PrEP and TDF2).
The drug's efficacy was highest in people who adhered to daily dosing (about 10% of participants), and overall, PrEP resulted in a 44% to nearly an 80% reduction in risk of contracting HIV, depending on the level of adherence and drug availability.
After the PrEP trial results came out, the US Centers for Disease Control and Prevention (CDC) developed interim guidance in January 2011 for physicians electing to provide PrEP for HIV prevention among men who have sex with men.
At this time, the CDC recommends that PrEP be used only men who have sex with men. In addition, to minimize the risk for drug resistance, PrEP should not be started in persons with signs or symptoms of acute viral infection unless HIV-negative status is confirmed by HIV RNA testing or a repeat antibody test is performed after the viral syndrome resolves.