Background
Long-acting agents hold promise for addressing challenges associated with adherence and persistence to daily oral PrEP. The ImPrEP CAB Brasil study aims to generate evidence to inform national policies about long-acting cabotegravir (CAB-LA) PrEP implementation within public health PrEP services in Brazil.
Methods
Study intervention consisted of person-centered choice of same-day delivery of oral TDF/FTC PrEP or CAB-LA (The Choice Cohort) for PrEP-naïve cis-MSM, non-binary and trans persons aged 18-30 years. Participants were enrolled from October 17, 2023 to October 31, 2024 and will be followed for 48-weeks, with the option to switching during follow-up. As comparison group, we assessed PrEP-naïve persons with the same demographics who initiated oral PrEP during the study period through the Brazilian public health system at ImPrEP clinics. PrEP coverage was defined as the proportion of persons covered by oral PrEP or CAB-LA during follow-up. We used pairwise comparisons with Bonferroni correction for PrEP coverage. We described injection visit coverage and HIV incidence.
Results
Of 1,447 participants enrolled in The Choice Cohort, 83% (N=1,200) chose CAB-LA. Most were cis-MSM (91%), 42% aged 18-24, 60% non-White.
A total of 3,744 CAB-LA injections were administered, 95.7% (n=3,583/3,744) delivered on time (+/-7days|) and 29 persons (2.4%; n=29/1,200) had at least one reload. Among persons using CAB-LA, 4% (n=48/1200) were lost to follow-up, 20.8% (n=10/48) of these received only the first injection. To date, 47 (3.2%) participants switched regimens, 26 from CAB-LA to oral PrEP and 21 from oral PrEP to CAB-LA. There were 8 seroconversions in 408.52 person-years of follow-up in the comparison group (incidence rate 1.96 [95%CI 0.98-3.92] per 100 person-years) and no seroconversions in 798.4 person-years in The Choice Cohort.
A total of 2,263 persons initiated oral PrEP in the comparison group. PrEP coverage in The Choice Cohort was 96.2% for CAB-LA arm and 64.1% for oral PrEP arm, and 47.4% for the comparison group (Figure). Pairwise comparisons of coverage indicated differences between: CAB-LA vs oral PrEP, CAB-LA vs comparison group, and oral PrEP vs comparison group (p<0·0001 for all comparisons).
Conclusions
CAB-LA significantly improved PrEP coverage and protection, showing promise in addressing adherence challenges to daily oral PrEP, particularly among young key populations. Injection visit coverage was high and consistent during follow-up.