July 21, 2015
Written by NIH
This post originally appeared on NIH’s website.
A clinical study funded by the National Institutes of Health has found that young, single black women in South Africa adhered to a daily pill regimen to prevent HIV infection — an HIV prevention strategy known as pre-exposure prophylaxis, or PrEP. This finding is the first strong indication that this population at substantial HIV risk could accept and reliably adhere to daily PrEP dosing. Men who have sex with men (MSM) and transgender women (TGW) in New York and Thailand also successfully adhered to daily dosing.
PrEP — which consists of a daily dose of two antiretrovirals, tenofovir and emtricitabine, in a single pill marketed as Truvada — prevents HIV infection when taken consistently. Although some previous placebo-controlled PrEP clinical trials in women in sub-Saharan Africa had found challenges with adherence, 76 percent of women assigned to take PrEP on a daily basis in the HIV Prevention Trials Network (HPTN) 067 study adhered to the prescribed regimen. MSM and TGW from Harlem and Bangkok who participated in the study adhered to the daily regimen 65 percent and 85 percent of the time, respectively.
Several investigators involved presented the key findings from the HPTN 067 trial, also known as the Alternative Dosing to Augment Pre-Exposure Prophylaxis Pill Taking (ADAPT) study, today at the 8th International AIDS Society Conference on HIV Pathogenesis, Treatment and Prevention in Vancouver, Canada.
“These are encouraging findings, demonstrating that if given access to Truvada, women and men will take it daily to prevent HIV infection,” Anthony S. Fauci, M.D., director of the National Institute of Allergy and Infectious Diseases at NIH, said. “This study takes a solid step toward connecting people at particularly high-risk for HIV with a proven prevention strategy that can protect them from infection.”
HPTN 067, a Phase II clinical study that began in 2013, was designed to identify the PrEP pill-taking schedules that people are most likely to follow. The study involved 179 women with a median age of 26 in Cape Town, South Africa; 179 black MSM and TGW in Harlem, New York; and 178 Thai MSM and TGW in Bangkok. Median ages of the Harlem and Bangkok participants was 30 and 31, respectively. HIV incidence in all of these populations is high. Study participants at the three sites were randomly assigned into three groups, each prescribed Truvada, with instructions and counseling to take the pill on either a daily schedule or one of two non-daily schedules for 24 weeks. The two non-daily schedules involved taking one pill either twice per week and another after sex, or one pill before and another after sex. Adherence was measured by techniques that included self-reporting, blood and hair analyses, and data from Wisepill devices, which record opening of pill cases. At all three study sites, adherence to the daily regimen was higher than adherence to the two non-daily regimens.
Those enrolled in this open-label study were educated about the efficacy of daily PrEP and knew they were taking active drugs rather than placebo. Because daily use of PrEP is the only regimen approved by the U.S. Food and Drug Administration and recommended by the U.S. Centers for Disease Control and Prevention, all participants were provided with HIV risk reduction counseling and offered condoms. Study participants who became infected during the course of the study were referred to local medical care for treatment.
“This is an important step forward for optimizing HIV prevention strategies for people who would otherwise be at high risk for acquiring HIV infection,” said Robert M. Grant, M.D., M.P.H., of the Gladstone Institutes and the University of California, San Francisco and study chair. “The findings will inform the next generation of PrEP research and the development of best practices regarding PrEP adherence and counseling.”