Background: Micafungin, 100 mg and 150 mg daily, has demonstrated noninferior efficacy versus caspofungin, 70 mg on day 1 (loading dose) followed by 50 mg daily (maintenance dose) in invasive candidiasis (IC). For invasive aspergillosis (IA) and IC, caspofungin has standard approved dosing (70 mg on day 1 followed by 50 mg daily). Micafungin has an approved recommended dosing of 100 mg daily (IC) and is not approved to treat IA. This study evaluated utilization patterns of caspofungin and micafungin in US hospitals in patients diagnosed with IC and IA.
Methods: The Aspen Healthcare Metrics Navigator database was analyzed. Patients discharged between January 2007 and December 2009 with International Classification of Diseases, Ninth Revision diagnosis codes of 112.5 (IC) and 117.3 (IA) and receiving caspofungin or micafungin were included. Standard dosing for caspofungin was defined as a maintenance dose of 50 mg daily during hospital stay (IC and IA), and standard dosing for micafungin was defined as a maintenance dose of 100 mg/d (IC) and 100 or 150 mg/d (IA) during hospital stay. Nonstandard dosing included escalation or de-escalation of dose during the hospitalization or doses inconsistent with the standard dosing definition.
Results: Over the 3-year period, 214 patients received caspofungin for IC (alone in 53 patients and combination therapy in 161 patients) and 66 patients for IA (alone in 6 patients and combination therapy in 60 patients). Similarly, 164 patients received micafungin for IC (alone in 42 patients and combination therapy in 122 patients) and 50 patients for IA (alone in 5 patients and combination therapy in 45 patients). For IC, standard dosing for caspofungin and micafungin was observed in 182 patients (85%) and 109 patients (66%), respectively. For IA, standard dosing for caspofungin and micafungin was observed in 59 patients (89%) and 38 patients (76%), respectively. Among the standard dosing observed for micafungin in IA, 32% of the patients received 150 mg/d. When patients who received only micafungin or caspofungin during their hospital stay were evaluated, more mean days of therapy for micafungin versus caspofungin were observed for treatment of IA (10.8 vs. 5.5) and IC (8.8 vs. 6.8), respectively.
Conclusion: Based on study definitions, caspofungin demonstrated higher rates of standard dose utilization versus micafungin. With no evidence of improved clinical outcomes, use of echinocandins at higher dosage can increase antifungal drug expenditure without additional benefits.