Cost-Effectiveness Analysis of Clesrovimab for Respiratory Syncytial Virus in Infants in the United States

Background/Objectives: Respiratory syncytial virus (RSV) causes a significant hospitalization burden in infants. The objective of this study was to evaluate the cost-effectiveness of introducing clesrovimab, a recently approved long-acting monoclonal antibody, in all US infants born during or entering their first RSV season. Methods: A decision analytical model simulated the clinical and economic impact of clesrovimab in a yearly birth cohort, compared with three alternative interventions: nirsevimab, palivizumab, and the RSVpreF maternal vaccine. Model inputs were obtained from the published literature. Efficacy estimates for clesrovimab were derived from post hoc analyses of randomized control trial data, which were conducted to align endpoints from different studies (nirsevimab and RSVpreF). Medically attended lower respiratory infection (MALRI), quality-adjusted life years (QALYs, 3% discounting), and costs (in 2024 USD) were evaluated from a societal perspective. Both deterministic and probabilistic sensitivity analyses were performed. Results: Clesrovimab resulted in fewer (38,252) RSV-related MALRI outcomes and was cost-saving compared to nirsevimab, with significant reductions in total costs (USD 98 million saved). When compared with palivizumab, clesrovimab and nirsevimab were estimated to cost USD 38,655 and USD 79,912 per QALY, respectively. Results were sensitive to changes in intervention costs, efficacy, and QALY loss due to RSV infection. Conclusions: Clesrovimab may significantly reduce the burden of RSV among US infants in their first RSV season and may save costs compared to nirsevimab.