Cabotegravir and rilpivirine for treatment of HIV infection in Africa: week 96 results from the phase 3b randomized, open-label, noninferiority CARES trial

Evaluation of the durable efficacy and safety of long-acting injectable therapy for HIV is needed in African populations. In a multicenter, open-label phase 3b trial, 512 African adults with HIV-1, stable on first-line oral therapy, with screening plasma viral load (VL) <50 copies ml^-1 and without past virologic failure were randomized (1:1) to continue oral therapy or switch to cabotegravir (600 mg) and rilpivirine (900 mg) intramuscular injections every 8 weeks (optional 4-week oral lead-in). VL was monitored every 24 weeks. Here the primary outcome for our analysis up to 96 weeks was VL <50 copies ml^-1, using the Food and Drug Administration snapshot algorithm (noninferiority margin 10%) in the intention-to-treat exposed population. At 96 weeks, 247/255 (97%) in the long-acting group and 250/257 (97%) in the oral therapy group had VL <50 copies ml^-1 (difference -0.4%; 95% confidence interval -3.1% to 2.0%), demonstrating noninferiority. Adverse events of severity grade ≥3 occurred in 41/255 (16%) in the long-acting group and in 22/257 (9%) in the oral therapy group, mostly considered unrelated to the study drug; only one treatment-related adverse event in the long-acting group led to a decision to discontinue treatment (injection-site abscess). Cabotegravir and rilpivirine long-acting therapy produced durable virologic suppression, met the prespecified noninferiority endpoint compared with oral therapy and demonstrated an acceptable safety and tolerability profile. Long-acting therapy may be considered for use in African treatment programs. PACTR registration: 202104874490818.