Cost-Effectiveness Analysis of Bezlotoxumab Added to Standard of Care Versus Standard of Care Alone for the Prevention of Recurrent Clostridium difficile Infection in High-Risk Patients in Spain.

INTRODUCTION: Clostridium difficile infection (CDI) is the major cause of infectious nosocomial diarrhoea and is associated with considerable morbidity, mortality and economic impact. Bezlotoxumab administered in combination with standard of care (SoC) antibiotic therapy prevents recurrent CDI. This study assessed the cost-effectiveness of bezlotoxumab added to SoC, compared to SoC alone, to prevent the recurrence of CDI in high-risk patients from the Spanish National Health System perspective.

METHODS: A Markov model was used to simulate the natural history of CDI over a lifetime horizon in five populations of patients at high risk of CDI recurrence according to MODIFY trials: (1) ≥ 65 years old; (2) severe CDI; (3) immunocompromised; (4) ≥ 1 CDI episode in the previous 6 months; and (5) ≥ 65 years old and with ≥ 1 CDI episode in the previous 6 months. The incremental cost-effectiveness ratio (ICER) expressed as cost per quality-adjusted life-year (QALY) gained was calculated. Deterministic (DSA) and probabilistic sensitivity analyses (PSA) were performed.

RESULTS: In all patient populations (from 1 to 5), bezlotoxumab added to SoC reduced CDI recurrence compared to SoC alone by 26.4, 19.5, 21.2, 26.6 and 39.7%, respectively. The resulting ICERs for the respective subgroups were €12,724, €17,495, €9545, €7386, and €4378. The model parameters with highest impact on the ICER were recurrence rate (first), mortality, and utility values. The probability that bezlotoxumab was cost-effective at a willingness-to-pay threshold of €21,000/QALY was 85.5%, 54.1%, 86.0%, 94.5%, 99.6%, respectively.

CONCLUSION: The results suggest that bezlotoxumab added to SoC compared to SoC alone is a cost-effective treatment to prevent the recurrence of CDI in high-risk patients. The influence of changes in model parameters on DSA results was higher in patients  ≥ 65 years old, with severe CDI and immunocompromised. Additionally, PSA estimated that the probability of cost-effectiveness exceeded 85% in most subgroups.

FUNDING: Merck Sharp & Dohme Corp.