Truvada for PrEP: How an HIV Treatment Drug Can Protect Against the Virus

The incidence of new HIV infections has remained stable since the mid-1990s at a rate of approximately 50,000 per year. Among those newly infected, African Americans, Latinos, and gay and bisexual men of all races and ethnicities remain disproportionately affected by HIV. There have been some noteworthy trends according to new analysis, with a 21% decrease in new HIV infections from 2008 to 2010 in African American women along with a 22% increase among young gay and bisexual men. When comparing estimated HIV infections in 2010 by route of transmission, 63% occurred in men who have sex with men (MSM), 25% heterosexuals, 3% MSM injection drug users (IDUs), and 8% IDUs.8 These statistics indicate that although prevention methods have been able to keep new infection rates constant, newer tools and approaches may be required in order to help decrease the incidence of new HIV infections, especially among those groups most at risk.

The Research

In Jaunary 2011, published results became available from the iPrEx trial on the efficacy and safety of daily oral tenofovir disoproxil fumarate (TDF) 300 mg / emtricitabine (FTC) 200 mg (brand name Truvada), as antiretroviral preexposure prophylaxis (PrEP) to reduce the risk for HIV acquisition among MSM. There was a 44% overall reduction in risk of HIV with the use of TDF/FTC. Since then, data from studies of PrEP among heterosexuals have also become available, prompting the Food and Drug Administration (FDA) to approve a label indication for Truvada on July 16, 2012 for the reduction of risk for sexual acquisition of HIV among adults, including both heterosexuals and MSM.1 In response to the newly approved indication, the Center for Disease Control (CDC) published the Interim Guidance for Clinicians Considering the Use of Pre-exposure Prophylaxis for the Prevention of HIV Infection in Heterosexually Active Adults in August 2012.

The FDA took into account data from four main trials when approving the use of Truvada for PrEP in heterosexuals (in addition to MSM). Partners PrEP and TDF2 are two studies that looked at the use of antiretroviral therapy (ART) in both adult men and women and found efficacy rates of 75% and 62%, respectively. These efficacy rates were associated with adherence rates of 97% and 84%, indicating that, as is true for MSM as well, Truvada is effective in reducing the risk of sexual HIV infection by heterosexual men and women only when used consistently.

FEM-PrEP and VOICE are two other studies that examined ART use in women, specifically. However, both trials were stopped early when the data safety monitoring boards concluded no evidence of efficacy based on very low levels of medication adherence.

This excerpt was cross-posted with the permission of Positively Aware. Read the full article.

Heather Free, Pharm.D., is manager of Community, a Walgreens pharmacy in Washington, D.C. Joni Chang is a Pharm.D. candidate who interned at Community.