Long-Acting Cabotegravir and Rilpivirine in People Living With HIV-1 Subtype A6: A Real-World Retrospective Study

This is a multicentre, international, real-world, retrospective observational study designed to evaluate clinical outcomes of long-acting injectable cabotegravir plus rilpivirine (CAB/RPV LA) in adults living with HIV-1. The study is conducted at HIV treatment centers in Poland, Germany, and the Czech Republic and is based on routinely collected clinical data from electronic medical records and paper charts. The study population includes treatment-experienced individuals aged 18 years or older who received at least one dose of CAB/RPV LA in routine clinical practice. Participants are grouped according to HIV-1 subtype: subtype A6, subtype B, and unknown subtype. Individuals with known subtype A6 are matched with individuals with subtype B using propensity score matching to reduce the impact of confounding factors. Participants with unknown subtype are analyzed as an unmatched group. Clinical data are collected from the time of CAB/RPV LA initiation (index date) and from follow-up visits closest to 6, 12, 18, and 24 months after initiation. Outcomes assessed include treatment persistence, adherence to injection schedules, discontinuation rates and reasons for discontinuation, and measures of virologic effectiveness. Virologic outcomes include viral suppression, viral rebound, and confirmed virologic failure as defined by standard HIV RNA criteria. For participants with unknown HIV-1 subtype, proviral DNA genotyping is performed after initial descriptive analyses to explore whether knowledge of HIV-1 subtype has prognostic relevance for clinical outcomes. Genotypic data are analyzed descriptively and may inform additional exploratory analyses. As this is a retrospective, non-interventional study using existing clinical data, no study-specific treatment interventions are performed. Safety data collection is limited to adverse events leading to treatment discontinuation, reflecting routine clinical practice. The study aims to provide clinically relevant real-world evidence on the use of CAB/RPV LA across different HIV-1 subtypes, with particular focus on subtype A6.