Fidaxomicin Versus Vancomycin as a First Line Treatment for C. difficile-Associated Diarrhea (CDAD) in Specific Patient Populations: A Pharmacoeconomic Evaluation

Abstract

Introduction:C. difficile-associated diarrhea (CDAD) costs the U.S. health care system >$1 billion in excess medical costs per year. This study evaluates the costs associated with utilizing fidaxomicin (FDX) or vancomycin (VAN) as a first-line therapy for CDAD from a U.S. hospital perspective. Methods: A decision-analytic model was developed to compare the health outcomes and hospital (inpatient) costs associated with CDAD episodes treated in the hospital with FDX (200 mg oral tablet) or VAN (125 mg compounded oral solution) as first-line therapy for CDAD in 5 patient groups (overall population, elderly, cancer, patients with concomitant antibiotic use, and renal impairment). Clinical inputs were derived from phase 3 clinical studies comparing FDX and VAN; costs for initial hospitalization and readmissions were based on published literature and an analysis of the healthcare cost and utilization project (HCUP) databases. FDX cost was assumed to be $210/day based on 29% WAC discount given in hospital; VAN cost was $20/day based on hospital-compounded oral solution. The model considered an initial episode and up to 2 additional recurrences of CDAD with approximately one-half of recurrent patients experiencing re-hospitalization. Recurrence rates were independent of previous treatment failure. Results: Hospitalization costs, particularly those attributed to the first episode of CDAD, comprised the majority of total inpatient costs associated with CDAD treatment (85-99% of total costs per patient). Initial hospitalization costs were similar for patients treated with FDX or VAN ($8,133.94 vs. $8,254.87 per patient) while drug costs were higher for patients treated with FDX ($1,198.49 vs. $128.27 per patient). Lower first and second recurrence rates with FDX resulted in fewer re-hospitalizations, offsetting all or most FDX drug costs. Average total hospital costs in the overall population were similar ($10,481 vs. $10,302 for FDX and VAN, respectively). In both the concomitant antibiotic use and cancer subpopulations, FDX was associated with overall cost savings due to higher initial cure rates and lower recurrence (FDX cost savings range $552-$1,127 per patient). In elderly and renal impairment populations, VAN resulted in slightly lower total costs (VAN cost savings range $282-$292 per patient). Conclusion: Use of FDX as first-line therapy in CDAD is associated with similar total costs compared to compounded VAN oral solution in the overall population, sizeable hospital cost savings in subgroups with cancer and concomitant antibiotic use, and modest cost increases in the elderly and renallyimpaired. The cost savings with FDX are directly attributable to lower recurrence rates leading to fewer re-hospitalizations. Disclosure - Broderick KC - Employee of Cubist Pharmaceuticals; Xu P - Employee of Cubist Pharmaceuticals; Corvino FA - Employee of Genesis Research, Research Consultant to Cubist; Zivkovic M - Employee of Genesis Research, Research Consultant to Cubist.