Pharmacokinetics, efficacy, and safety of caspofungin in Japanese pediatric patients with invasive candidiasis and invasive aspergillosis

The antifungal agents approved in Japan for pediatric use are limited and many unapproved drugs are actually used without clear instruction for dosage. We investigated the pharmacokinetics of caspofungin for the treatment of invasive candidiasis and invasive aspergillosis in 20 Japanese pediatric patients using a pediatric-specific dosage based on body surface area. Caspofungin was administered intravenously over 60 min as 70 mg/m2 on Day 1, followed by 50 mg/m2 per day. Five or 4 point blood sampling were done in 15 patients on Day 4-5 to calculate AUC0-24 h. The geometric means (95% confidence interval) of C24 h and AUC0-24 h in the pediatric patients were 3.3(2.5, 4.4) μg/mL and 175.1 (139.3, 220.1) μg hr/mL, respectively, which were comparable to those in Japanese adult patients [3.2 (2.8, 3.5) μg/mL and 144.9 (131.7, 159.3) μg hr/mL, respectively]. Among the 20 patients, 10 (50%) had at least 1 drug-related adverse event which was considered related to caspofungin therapy. No drug-related serious adverse event and no death occurred. The most common drug-related adverse events were events relating to hepatic function (mainly increases in ALT and AST). The overall success in efficacy was observed in 13 of 20 patients. In conclusion, once daily administration of caspofungin (70 mg/m2 on Day 1, followed by 50 mg/m2 [maximum daily dose not to exceed 70 mg]), which is the same dosage being used in overseas, achieved sufficient drug exposure and a favorable efficacy and acceptable safety profile in Japanese pediatric patients with invasive fungal infections.