The 96-week outcomes and pharmacokinetics of long-acting cabotegravir plus rilpivirine in South Africans

Abstract

Background: Evaluating long-term efficacy, safety and pharmacokinetics of long-acting cabotegravir + rilpivirine (CAB+RPV LA) in sub-Saharan African populations is important because of the region’s unique demographics and antiretroviral therapy resistance patterns.

Objectives: To describe the 96-week efficacy, safety and pharmacokinetics of CAB+RPV LA in South African participants from the pooled FLAIR and ATLAS-2M Phase 3/3b randomised studies.

Method: Primary endpoint: proportion of participants with plasma HIV-1 RNA levels ≥ 50 copies/mL at Week 96. Secondary endpoints: proportion of participants with plasma HIV-1 RNA levels < 50 copies/mL, confirmed virological failure (CVF; two consecutive plasma HIV-1 RNA ≥ 200 copies/mL), adverse events and pharmacokinetics.

Results: Sixty-six participants were included, (CAB+RPV LA, n = 49; current oral antiretroviral regimen [CAR], n = 17). Forty-five (92%) on CAB+RPV LA and 15 (88%) on CAR maintained HIV-1 RNA levels < 50 copies/mL. At Week 96, two participants, one in each arm, had CVF. Ninety per cent on CAB+RPV LA and 76% on CAR of participants experienced an adverse event; six (12%) of which were drug-related (CAB+RPV LA: n = 6). Injection-site reactions were common (78% [Grade 1: 80%; Grade 2: 20%]). CAB and RPV trough plasma concentrations remained above respective in vitro protein-adjusted 90% inhibitory concentrations following all doses.

Conclusion: This subgroup analysis of South African participants demonstrated durable efficacy, acceptable safety profile and pharmacokinetics of injectable CAB+RPV LA up to 96 weeks, consistent with long-term data from other regions and studies.