SEATTLE — Results from the iPrEx open-label extension trial show several key patient characteristics that predicted engagement with pre-exposure prophylaxis, including high school education, condom use and having an HIV-positive partner.
David V. Glidden, PhD, professor of biostatistics at the University of California, San Francisco, and colleagues assessed predictors of PrEP adherence in former participants of iPrEx OLE, which included 1,603 HIV-negative men who have sex with men and transgender women from 11 sites in four continents. Participants were offered up to 18 months of open-label Truvada (emtricitabine/tenofovir disoproxil fumarate, Gilead Sciences; FTC/TDF) and were followed up with HIV testing and medical assessments regardless of whether they elected to receive PrEP. Seventy-six percent of participants opted to receive the combination treatment.
The researchers measured exposure to FTC/TDF in dried blood spots. Highly protective drug concentrations were consistent with taking four or more pills per week.
At 12 months, 813 participants had been dispensed PrEP at their last visit, and less than half of these (n = 354) had FTC/TDF exposure levels consistent with taking at least four pills per week, yielding highly protective concentrations of the drug in 22% of those offered PrEP.
Percentages of MSM and transgender women who took at least four pills per week varied by site (P < .001), ranging from 11% to 63%. In multivariable logistic regression analysis, PrEP adherence was greater among those who reported non-condom insertive anal intercourse (P = .02), a diagnosed STI (P = .046), an HIV-positive partner (P = .02) and secondary (P = .03) or higher (P < .001) education.
Glidden DV, et al. Abstract 970. Presented at: Conference on Retroviruses and Opportunistic Infections; Feb. 23-26, 2015; Seattle.
Disclosure: Glidden reports no relevant financial disclosures.