- Category: HIV Prevention
- Published on Thursday, 10 May 2012 00:00
- Written by Liz Highleyman
On May 10, 2012, the Antiviral Drugs Advisory Committee of the U.S. Food and Drug Administration (FDA) decisively recommended approval of Truvada -- Gilead Sciences' tenofovir/emtricitabine combination pill -- for pre-exposure prophylaxis (PrEP) to prevent sexual transmission of HIV.
[Editor's note: on June 7 Gilead announced that the FDA has delayed its decision about Truvada PrEP to allow more time for development of a risk evaluation and management strategy; the new projected date for an approval decision is September 14.]
The committee voted 19 to 3 in favor of approving Truvada PrEP for men who have sex with men, 19 to 2 (with 1 abstention) for HIV negative partners in serodiscordant couples, and 12 to 8 (with 2 abstentions) for other individuals at risk for acquiring HIV through sex
"This brings us closer to a watershed for global HIV prevention efforts," said AVAC executive director Mitchell Warren in a press release issued immediately following the votes. "PrEP, while not a panacea, will be an essential additional part to the world’s success in ending AIDS."
Gilead requested approval for the expanded indication in December 2011 based on a growing body of evidence showing that tenofovir/emtricitabine can lower the risk of HIV acquisition if taken every day.
The iPrEx study of gay and bisexual men (plus a small number of transgender women) and the Partners PrEP and TDF2 studies of heterosexual men and women showed that once-daily Truvada PrEP dramatically reduced the incidence of new infections.
The data is not unanimous, however. The Fem-PrEP study of Truvada for heterosexual women was halted early because it was unable to demonstrate a preventive effect, as was an arm of the VOICE trial testing tenofovir alone.
Further data presented at this year's Retrovirus conference (CROI 2012) indicated that adherence and adequate drug levels in the body are keys to PrEP's effectiveness. In Partners PrEP and iPrEx, new infections were reduced by about 90% among people with blood drug levels indicating good adherence.
While Truvada PrEP appears highly effective -- at least for selected, high-risk populations that use it as part of a comprehensive prevention strategy that also includes condoms and risk-reduction counseling -- advocates and public health officials have raised concerns regarding the difficulty of ensuring good adherence, long-term side effects (especially bone and kidney problems), drug resistance, and cost and access.
The Los Angeles-based AIDS Healthcare Foundation has been a vociferous critic of Truvada PrEP. "Any approach that relies on adherence for people who don't have a disease is going to fail," AHF president Michael Weinstein said in advance of today's hearing.
Some have expressed concern that since Truvada is not 100% effective for prevention, PrEP may give people unwarranted confidence that leads them to give up safer sex practices. Studies to date, however, have not demonstrated this so-called "behavioral disinhibition."
AVAC urged the U.S. Centers for Disease Control and Prevention (CDC), the World Health Organization (WHO), and other public health agencies to quickly issue guidance on the appropriate use of Truvada PrEP for different populations, and stressed that funding for PrEP "should not detract from other essential HIV prevention and treatment efforts."
The FDA is expected to make a decision about approval of Truvada PrEP by June 15. The agency is not required to follow its committees' recommendations but it usually does so.
Background material about Truvada PrEP is available on the FDA web site. The FDA plans to provide an archived webcast of the advisory committee meeting on the same site.
Associated Press. FDA advisers back approval for first pill shown to protect healthy people from AIDS virus. May 10, 2012.
AVAC. AVAC Urges FDA Approval of PrEP Following Positive Advisory Committee Recommendation; Lays out Priorities to Ensure Access. Press release. May 10, 2012.
Gilead Sciences. FDA Advisory Committee Supports Approval of Gilead’s Truvada for Reducing the Risk of Acquiring HIV. Press release. May 10, 2012.
D Beasley. HIV Pill for Prevention Debated as FDA Ruling Nears. Reuters. May 9, 2012.