Cabotegravir and Rilpivirine Long-Acting Antiretroviral Therapy Administered Every 2 Months is Cost-Effective for the Treatment of HIV-1 in Spain

INTRODUCTION: Current antiretroviral therapies (ARTs) have improved outcomes for people living with HIV. However, the requirement to adhere to lifelong daily oral dosing may be challenging for some people living with HIV, leading to suboptimal adherence and therefore reduced treatment effectiveness. Treatment with long-acting (LA) ART may improve adherence and health-related quality of life. The objective of this study was to evaluate the cost-effectiveness of cabotegravir + rilpivirine (CAB+RPV) LA administered every 2 months (Q2M) compared with current ART administered as daily oral single-tablet regimens (STRs) from a Spanish National Healthcare System perspective. METHODS: A hybrid decision-tree and Markov state-transition model was used with pooled data from three phase III/IIIb trials (FLAIR, ATLAS, and ATLAS-2M) over a lifetime horizon, with health states defined by viral load and CD4(+) cell count. Direct costs (in €) were taken from Spanish public sources from 2021 and several deterministic and probabilistic analyses were carried out. An annual 3% discount rate was applied to both costs and utilities. RESULTS: Over the lifetime horizon, CAB+RPV LA Q2M was associated with an additional 0.27 quality-adjusted life years (QALYs) and slightly greater lifetime costs (€4003) versus daily oral ART, leading to an incremental cost-effectiveness ratio of €15,003/QALY, below the commonly accepted €30,000/QALY willingness-to-pay threshold in Spain. All scenario analyses showed consistent results, and the probabilistic sensitivity analysis showed cost-effectiveness compared with daily oral STRs in 62.4% of simulations, being dominant in 0.3%. CONCLUSION: From the Spanish National Health System perspective, CAB+RPV LA Q2M is a cost-effective alternative compared with the current options of daily oral STR regimens for HIV treatment. CLINICAL TRIALS REGISTRATION: ATLAS, NCT02951052; ATLAS-2M, NCT03299049; FLAIR, NCT02938520. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40121-023-00840-y.