Eligibility for Intramuscular Cabotegravir/Rilpivirine in HIV-Positive Patients: An Observational Study

Background: HIV treatment has advanced significantly with the introduction of simpler antiretroviral regimens, but adherence remains a challenge. In this context, the long-acting injectable combination cabotegravir/rilpivirine (CAB/RPV) emerges as a promising alternative to improve adherence and quality of life for patients. Objective: The purpose of this study was to determine the proportion of patients with HIV-1 on antiretroviral therapy (ART) who meet the criteria for the use of intramuscular CAB/RPV. Methods: A single-center, retrospective observational study was conducted on patients with HIV-1 receiving ART at a Spanish hospital. Adult patients with at least 6 months of stable ART and a viral load result in the previous 12 months were included. Pregnant women, patients with less than 6 months of ART, or those without a recent viral load were excluded. The primary endpoint was the proportion of patients meeting the criteria for intramuscular CAB/RPV: undetectable viral load, stable ART, adherence >90%, no resistance to non-nucleoside reverse transcriptase inhibitors (NNRTIs)/integrase strand transfer inhibitors (INSTIs), no enzyme inducers, no anticoagulants, and no hepatitis B virus (HBV) infection. We also measure the risk of virological failure. Costs and treatment complexity were analyzed. Results: A total of 194 patients were included. In total, 68% met the criteria for intramuscular CAB/RPV. The main reasons for ineligibility were a recent ART switch (16%) and lack of adherence (11.3%). The mean annual incremental cost per patient when switching to CAB/RPV was €651.51. Conclusion and Relevance: A considerable proportion of patients with HIV meet the criteria for intramuscular CAB/RPV. However, lack of adherence and the costs associated with intramuscular therapy represent barriers to its implementation. Strategies to improve adherence and cost-effectiveness studies are needed.