Evaluating the Potential Clinical and Economic Impact of Clesrovimab for Infants in England and Wales

BackgroundRespiratory syncytial virus (RSV) infects nearly all children under two years, causing mild lower respiratory tract infections (LRTIs) although serious disease, mortality and long-term recurrent wheezing can also occur. This study evaluates the health and economic impact of various RSV prevention strategies (monoclonal antibodies [mAb] such as clesrovimab, nirsevimab, palivizumab [high risk infants only] or maternal vaccination) in infants in England and Wales. MethodsA previously published decision tree model was adapted to estimate RSV LRTIs and associated costs over one year among a cohort of infants entering their first RSV season in England and Wales. Clinical trial data were used for efficacy inputs alongside country-specific epidemiology and costs to assess the impact of year-round and seasonal mAb programs (without and with catch-up [for infants born out of season]) alongside maternal vaccination. Deterministic sensitivity analyses of incremental treatment costs and QALYs were performed. ResultsSeasonal administration of clesrovimab with and without catch-up led to fewer RSV-associated LRTI cases and lower treatment costs compared to other RSV intervention strategies. Without catch-up, clesrovimab reduced RSV-LRTI cases by 18%-27% versus palivizumab, 3%-4% versus nirsevimab and 2%-13% versus maternal vaccine. With catch-up, RSV-LRTI outcomes reductions by clesrovimab were greater: 60%-70% versus palivizumab, 14%-20% versus nirsevimab, and 43%-54% versus maternal vaccination. It also reduced treatment costs by {pound}37.0 million compared to palivizumab, {pound}4.0 million compared to nirsevimab, and {pound}26.0 million compared to maternal vaccination. Coverage and efficacies were the most influential parameters. ConclusionsClesrovimab is projected to substantially reduce RSV-associated clinical outcomes and costs compared to both standard of care and potential new RSV prevention measures in England and Wales.