New study finds high adherence to daily pill for HIV prevention among both men and women

Sub-analysis underscores the value of PrEP in protecting women's health

July 20, 2015 -New CDC data from Botswana show that both women and men were highly adherent to using daily oral HIV pre-exposure prophylaxis, or PrEP, over the course of a one-year open-label study. Because this study more closely replicated a real-world setting than its preceding clinical trial – since participants received no financial compensation and all were aware they were taking an active drug – the findings may provide a better indication of likely adherence among women and men seeking to use PrEP for HIV prevention.

Title: Characteristics and Oral PrEP Adherence in the TDF2 Open-Label Extension in Botswana (Oral Presentation, Faith Henderson) 

Overview: This analysis shows that HIV-uninfected and sexually active heterosexual women and men enrolled in the 12-month TDF2 open-label extension (OLE) were highly adherent to a daily oral combination of tenofovir and emtricitabine (TDF/FTC) for PrEP, and showed no increase in sexual risk behavior. Despite a high risk of infection in Botswana, where previous estimates indicate approximately 22 percent of people ages 15 to 49 are living with HIV, no new infections occurred among study participants over the trial period.  Specific findings include:

• An analysis of dried blood specimens (DBS) collected from a sample of 120 participants showed that the vast majority of participants had detectable drug levels throughout the study – overall, participants had detectable drug levels at 93 percent of visits. Detectable drug levels are evidence that participants have taken their pills within the past few days. Further, a high proportion of participants had detectable drug levels throughout each time period analyzed: 95 percent, 93 percent, 94 percent, and 91 percent had detectable drug at 1-3 months, 4-6 months, 7-9 months, and 10-12 months, respectively.
• Among those with drug level data, women had detectable drug at 87 percent of visits and men at 96 percent.
• Sexual risk behavior declined over the course of the study: among both men and women, the number of reported sex partners in the past 30 days decreased by 12 percent, and the number of sex acts without a condom decreased by 39 percent.

A strong body of existing research shows that daily oral PrEP can be highly effective for both heterosexual men and women, when taken consistently. While some PrEP studies have found that women were not protected from HIV because they did not take the medication regularly, as prescribed, together with encouraging recent evidence from the ADAPT study among women in Cape Town, these new findings confirm that women who are at risk for HIV can adhere to daily PrEP. With women and girls accounting for more than half of all people living with HIV worldwide – and 10,000 new infections occurring among women each year in the U.S. alone – PrEP offers a much needed, female controlled method of protection for women at high risk.

Lead Author: Faith Henderson, CDC