Risk factors of mortality and comparative in-vitro efficacy of anidulafungin, caspofungin, and micafungin for candidemia

Background: Although echinocandins have high in vitro antifungal efficacy according to prior reports, comparative studies on the clinical cure rates of anidulafungin, caspofungin, and micafungin in systemic candida infections have not yet been reported. Methods: Interpretation of clinical and microbiological responses to anidulafungin, caspofungin, and micafungin in 109 cases of candidemia was done according to the published criteria. The clinical cure rates between patients treated with echinocandins and patients treated with fluconazole were also compared. The minimal inhibitory concentrations (MICs) of anidulafungin, caspofungin, micafungin, and fluconazole for these 109 blood isolates of candida were determined with the Clinical and Laboratory Standards Institute M27-A reference microdilution method. Logistic regression with forward selection was used to determine the important factors of prognosis with variables such as age, underlying diseases, acute physiology and chronic health evaluation (APACHE) III score, persistent candidemia, and antimicrobial therapy. Results: Among the 109 cases of candidemia, 70 were treated with echinocandins, azoles, or amphotericin B for ≥7 days. The clinical cure rate of cases treated with antifungal agents adequately (≥7 days) and inadequately (<7 days) were 44/70 (62.9%) and 4/39 (10.2%), respectively, with significant difference (p < 0.0001). Clinical cure rates of anidulafungin, caspofungin, micafungin, and fluconazole were 18/30 (60.0%), 8/9 (88.9%), 5/7 (71.4%), and 9/18 (50%), respectively. The difference in APACHE III score between treatment success and failure cases was significant. The MIC₅₀/MIC₉₀ of anidulafungin, caspofungin, and micafungin for all Candida spp. were 0.03/1 μg/mL, 0.06/0.5 μg/mL, and 0.008/1 μg/mL, respectively. Conclusion: Adequate antifungal therapy and APACHE III score are both independent factors affecting the clinical outcome. The clinical cure rate of the echinocandins group was higher than that of the fluconazole group without significant difference. Although caspofungin had the best clinical cure rate in this study, there was no significant difference between the clinical cure rates among these three echinocandins. All Candida spp. were susceptible in vitro to these three echinocandins.