Evaluation of caspofungin or micafungin as empiric antifungal therapy in adult patients with persistent febrile neutropenia: a retrospective, observational, sequential cohort analysis.

BACKGROUND: Caspofungin is approved in the United States for empiric antifungal therapy for persistent febrile neutropenia (FN). There are limited data about the use of other echinocandins in this setting.
OBJECTIVE: After a formulary change, we retrospectively evaluated the safety and effectiveness of caspofungin and micafungin as empiric antifungal therapy for FN at Brigham and Women's Hospital (Boston, Massachusetts).
METHODS: This was a retrospective, observational, sequential cohort study. We identified patients who had received >or=2 doses on concurrent days of either caspofungin (between November 2005 and October 2006) or micafungin (between November 2006 and October 2007) for empiric FN therapy. Patients were included for analysis if they were neutropenic (absolute neutrophil count <500 cells/microL) and febrile (temperature >or=100.5 degrees F [>or=38 degrees C]). Patients without previous exposure to an echinocandin were included; those included in the caspofungin cohort were excluded from the micafungin cohort. Those who had previously received another systemic antifungal agent for FN therapy (except fluconazole for mucosal candidiasis) were excluded. Patients were followed through hospital discharge. Outcomes analyzed were successful treatment of baseline invasive fungal disease (IFD), incidence of breakthrough IFD, overall mortality, and discontinuation because of adverse events (AEs). IFD was diagnosed and classified according to current European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and the National Institute of Allergy and Infectious Diseases Mycoses Study Group Consensus Group criteria.
RESULTS: Three hundred twenty-three patients met inclusion criteria (caspofungin, n = 149; micafungin, n = 174). Median age was 49 years in both the caspofungin and micafungin groups; 80 (53.7%) and 99 (56.9%) patients in each group, respectively, were men. Fluconazole prophylaxis had been administered to 30 patients (20.1%) treated with caspofungin and 21 patients (12.1%) treated with micafungin. Caspofungin was administered at 70 mg for one dose, followed by 50 mg daily; micafungin was administered at 100 mg daily. The median duration of therapy and of hospitalization were 10 days and 29 days, respectively, with caspofungin, and 9 days and 28 days with micafungin (both, P = NS between groups). Twelve patients (8.1%) in the caspofungin cohort and 13 (7.5%) in the micafungin cohort died during the study period (P = NS). There were 3 cases (2.0%) of baseline IFD in the caspofungin cohort and 6 (3.4%) in the micafungin cohort (P = NS); 6 were successfully treated (caspofungin, 2 [1.3% of entire group]; micafungin, 4 [2.37% of entire group]; P = NS). Breakthrough IFD was diagnosed in 16 patients (10.7%) receiving caspofungin and 21 (12.1%) receiving micafungin (P = NS). AEs requiring echinocandin discontinuation were uncommon (caspofungin, 2 cases of rash and 1 anaphylactoid infusion reaction [2.0%]; mica-fungin, 1 liver function test elevation >or=5 times the upper limit of normal and 1 maculopapular rash [1.1%]; P = NS).
CONCLUSION: Micafungin, as empiric antifungal therapy for persistent FN, did not appear to differ significantly from caspofungin in terms of safety profile or efficacy in the adult patients included in this sequential cohort analysis at one institution. ClinicalTrials.gov identifier: NCT00723073.