Cost-effectiveness of bezlotoxumab and fidaxomicin for initial Clostridioides difficile infection

Treatment of Clostridioides difficile infection (CDI) has undergone significant change in recent years with the introduction of fidaxomicin and bezlotoxumab. This study evaluated the cost-effectiveness of fidaxomicin and bezlotoxumab for initial CDI compared with standard therapy with oral vancomycin.A Markov model with eight health states was built based on transition probabilities, costs and health utilities derived from literature to evaluate the cost-effectiveness of standard fidaxomicin, bezlotoxumab plus vancomycin, and extended-pulsed fidaxomicin versus standard oral vancomycin over a lifetime horizon from the US societal perspective.For overall CDI treatment, oral vancomycin had a cost of $39 178 and was associated with a gain of 11.64 quality-adjusted life-years (QALYs). Extended-pulsed fidaxomicin had a higher QALY gain of 11.65 at a lower cost of $37 613, and therefore was dominant over vancomycin. Standard fidaxomicin had a QALY gain of 11.94 versus vancomycin at an incremental cost of $495 per QALY. Bezlotoxumab plus vancomycin led to a QALY gain of 11.77 at an incremental cost of $17 746 per QALY. At the willingness-to-pay (WTP) threshold of $150 000 per QALY, extended-pulsed fidaxomicin, bezlotoxumab plus vancomycin and standard fidaxomicin were more cost-effective compared with vancomycin alone, yielding incremental net monetary benefits of $3248, $17 011 and $44 308, respectively. One-way sensitivity analysis suggested that the probabilities of sustained cure from the initial episode were the most sensitive inputs, and results were overall not particularly sensitive to any drug costs.Based on a WTP threshold of $150 000, standard fidaxomicin was estimated to be the most cost-effective treatment. Standard-of-care vancomycin was dominated by extended-pulsed fidaxomicin for treating an episode of CDI and preventing further recurrence, and the addition of bezlotoxumab to vancomycin was dominated by standard fidaxomicin.