Cost-effectiveness of fidaxomicin for the treatment of severe Clostridium difficile infection in hospitalized patients in North America

Purpose: Current guidelines for C. difficile-associated diarrhea (CDAD) recommend oral vancomycin as treatment for severe infection. A new macrocyclic antibiotic, fidaxomicin, boasts similar cure rates and lower rates of recurrence. The price of a course of fidaxomicin exceeds $2,800 while the price of oral vancomycin is near $1,200. This study examines the cost-effectiveness of fidaxomicin compared with vancomycin for the treatment of severe Clostridium difficile infection (CDI) in the inpatient setting.

Methods: A decision analytic model was developed to project the costs associated with the number of days a patient spends as an inpatient after primary infection with C. difficile. Clinical data was extracted from Phase 3 clinical trials of fidaxomicin and supported by other trials identified by systematic literature review. Cost data were taken from available literature and adjusted to 2011 US dollars.

Results: A base case analysis resulted in a cost of $8,370 per patient treated with vancomycin and $10,469 per patient treated with fidaxomicin. Monte Carlo simulations resulted in fidaxomicin being dominated by vancomycin; treatment with vancomycin provided an incremental benefit of 93 hospital days averted per 100 patients with CDI and resulted in a cost savings of $2,900 per patient. Sensitivity analyses showed that fidaxomicin becomes the more cost-effective option if more than 25.7 days are spent in the hospital for relapse; otherwise vancomycin remains the less costly option. If the cure rate for vancomycin falls below 75.6%, fidaxomicin becomes the more economical option.

Conclusion: This cost-effectiveness analysis demonstrated that fidaxomicin costs an additional $2,100 per patient and results in a length of stay that is slightly greater than if the patient had been treated with vancomycin. Fidaxomicin may be a cost-effective treatment in patients who are older, have comorbidities, have secondary or hospital-acquired CDI, or are at high risk for relapse. Otherwise, vancomycin appears to be a preferable strategy.