According to a recent press release, in a study of open-label Truvada as daily pre-exposure prophylaxis (PrEP) to prevent HIV among 427 young African women and adolescent girls, 95 percent initiated the HIV prevention strategy, and most used PrEP for the first three months. However, PrEP use fell among participants in this critical population during a year of follow-up clinic visits, although HIV incidence at 12 months was low. The preliminary results suggest that tailored, evidence-based adherence support strategies may be needed to durably engage young African women in consistent PrEP use. The study, known as HPTN 082, was supported by the National Institute of Allergy and Infectious Diseases (NIAID) and the National Institute of Mental Health (NIMH), both parts of the National Institutes of Health. The data were presented at the 10th International AIDS Society Conference on HIV Science.
Young women and girls in sub-Saharan Africa account for 3 million of the 4 million people aged 15-26 with HIV in the region. The NIH-sponsored HIV Prevention Trials Network (HPTN) reports that recent clinical trials had unacceptably high HIV incidence rates of 5 to 6 percent per year among young African women in this age group.
HPTN investigators conducted the Phase 4 clinical trial, known as “Evaluation of Daily Oral PrEP as a Primary Prevention Strategy for Young African Women: A Vanguard Study.” At clinic visits three months after initiating PrEP, 84 percent of 371 study participants who returned for follow-up had detectable levels of tenofovir diphosphate (TFV-DP)—a metabolite of one of the antiretrovirals in Truvada—in their blood according to dried blood spot analyses. Among these participants, 25 percent had TFV-DP levels suggesting “high adherence.” At six- and 12-month follow-up visits, investigators found that participants with detectable levels of TFV-DP declined to 57 percent and 31 percent, respectively. Only nine percent of young women had TFV-DP levels associated with high adherence at 12 months. Overall, four women acquired HIV during the study, all of whom had undetectable drug levels in their blood, suggesting limited adherence to PrEP.
In the study, HIV-negative women and girls—ages 16 to 25—received HIV prevention counseling at an initial visit and were offered daily oral Truvada as PrEP. Participants who accepted PrEP as well as those who initially declined PrEP were followed for up to a year at clinics in Cape Town and Johannesburg, South Africa, and Harare, Zimbabwe. All participants who accepted PrEP received standard adherence support services, including counseling, information about peer clubs and SMS text messaging reminders. Approximately half of participants who accepted PrEP were randomized to also receive counseling that included information about their drug-level results throughout the clinical trial. Investigators saw no difference in drug levels between the two groups at three, six or 12 months, indicating that drug level feedback did not improve PrEP adherence.
The HPTN 082 team plans to conduct further analyses, including qualitative interviews with up to 75 study participants, to assess why some women chose to accept or decline PrEP, and to identify specific adherence challenges. Interviews also may illuminate whether a participant’s risk behavior or perception of personal HIV risk changed throughout the study, informing a potential choice to continue or discontinue PrEP use.
