July 21, 2015
Written by HIV Prevention Trials Network
This post originally appeared on the HPTN website.
VANCOUVER, B.C. and DURHAM, N.C. – Results from HPTN 067, a Phase II, randomized, open-label study, demonstrate most study participants had higher coverage of sex events and better adherence when they were assigned to the daily dosing arm, investigators from the HIV Prevention Trials Network (HPTN) reported today at the 8th International AIDS Society (IAS) Conference on HIV Pathogenesis, Treatment and Prevention in Vancouver, Canada. HPTN 067, also known as the ADAPT Study, was designed to evaluate the feasibility of non-daily pre-exposure prophylaxis (PrEP) regimens. The study evaluated acceptability and use of three different oral PrEP regimens: daily, twice weekly with a dose after sex, and one dosebefore and another after sex. The study was not designed to assess the efficacy of the different regimens in preventing HIV, and participants were informed that only the daily regimen has been proven effective to prevent HIV infection.
The study of more than 500 participants included women in Cape Town, South Africa, and men who have sex with men (MSM) and transgender women (TGW) in Bangkok, Thailand, and Harlem, N.Y. The study was designed to assess whether non-daily use of oral FTC/TDF as PrEP, compared with daily use, would demonstrate equivalent coverage of sex acts, lower number of pills needed for coverage and decreased self-reported drug side effects over 24 weeks. The study also evaluated self-reported adherence and analyzed drug levels in the blood of participants.
Coverage of sex acts, that is taking pills around the time of sex acts, was defined as having taken one tablet within four days (96 hours) prior to sex and one tablet within one day (24 hours) after sex. The measure was used to assess pill taking around the time of sex, but this amount of drug is not known to be protective. Adherence was defined as the number of pills taken compared to the number of pills instructed to take based on self-reported sex acts.
“The ADAPT study was designed to see if participants assigned to a non-daily dosing schedule would take their pills as prescribed. If participants were able to take fewer pills at times when they were not having sex, there could be greater satisfaction with PrEP services and cost savings if these regimens later proved to be effective and were recommended,” said Robert Grant, M.D., M.P.H., of the Gladstone Institutes, the University of California, San Francisco (UCSF) and principal investigator for HPTN 067. “Our overall goal was to learn more about people’s experience with PrEP, and how different dosing recommendations affect that experience.”