Successful Empirical Antifungal Therapy of Intravenous Itraconazole with Pharmacokinetic Evidence in Pediatric Cancer Patients Undergoing Hematopoietic Stem Cell Transplantation

Empirical antifungal therapy prevents invasive fungal infections in patients with cancer. This study assessed the empirical efficacy of intravenous itraconazole in pediatric patients undergoing hematopoietic stem cell transplantation, and investigated the pharmacokinetics and clinical implications. Oral itraconazole syrup was started (2.5 mg/kg twice daily) for prophylaxis, and patients with persistent neutropenic fever for more than 2 days were switched to intravenous itraconazole (5 mg/kg twice daily for 2 days for induction and 5 mg/kg daily for maintenance) as empirical treatment. Empirical antifungal efficacy was assessed retrospectively in 159 transplantations, and a full pharmacokinetic study was prospectively conducted in six of these patients. Successful antifungal efficacy was defined as the fulfillment of all components of a five-part composite end point. The overall empirical antifungal success rate fulfilling all criteria was 42.1 %. No death or drug-related serious adverse events occurred during the study. Mean trough plasma concentration of itraconazole after oral prophylaxis and intravenous induction were 577.2 and 1659.7 μg/L, respectively. Mean area under the concentration-time curve of itraconazole and its metabolite at steady state were 42,837 ± 24,746 μg·h/L and 63,094 ± 19,255 μg·h/L. Intravenous itraconazole was effective and safe as an empirical antifungal agent in pediatric patients; this was due to the fast and satisfactory increase in drug concentration by switching from oral to intravenous therapy.