2122. Isavuconazonium for Invasive Fungal Therapy: Single-Center Pediatric Experience

BACKGROUND: Isavuconazole (ISZ), dosed as the pre-drug isavuconazonium (ISM), is active against a wide variety of clinically important fungal pathogens. ISM is approved for the treatment of invasive aspergillosis and mucormycosis in adults ≥18 years of age. We present our experience with ISM to treat proven or to prevent fungal infection in pediatric patients. METHODS: In a retrospective review of patients who received ISM at our institution between April 2016 and April 2019, we abstracted demographic information, primary diagnosis, indication for ISM therapy, ISZ serum concentrations if available, and outcomes. RESULTS: Of 16 patients who received ISM, 12 were < 18 years of age (range 6–17 years). Underlying conditions included leukemia (n = 8), lymphoma (n = 1), post BMT (n = 1), diabetes (n = 1), and cardiac transplant (n = 1). Nine (75%) had proven invasive fungal infection with aspergillosis (n = 2), zygomycosis (n = 3), mixed aspergillosis and zygomycosis (n = 2), mixed Rhizopus and Scedosporium (n = 1), and pathology only (n = 1). Five of these 9 patients received combination ISM and liposomal amphotericin initially, followed by monotherapy with ISM in 4 patients after a mean of 26 days (range 6–63), and continued dual therapy in the fifth. The other 4 received liposomal amphotericin with or without other azoles prior to changing to ISM monotherapy. ISM dosing was 10 mg/kg q8h on days 1 and 2, followed by q24 thereafter, up to a maximum of 372 mg/dose. There were 19 measured ISZ serum concentrations obtained from 8 patients after >1 week of verified inpatient dosing, ranging from 1.0 to 7.5 mg/L, above the MIC in all cases when known. Five (42%) patients died of underlying non-mycological causes, 1 (8%) died of progressive scedosporiosis, and 6 (50%) improved. The two patients receiving ISM prophylaxis did not suffer a breakthrough fungal infection. ISM was well tolerated with no dose-limiting, drug-related toxicities noted. CONCLUSION: ISM is a well-tolerated therapeutic option in pediatric patients at risk for or with invasive mycosis. Only 1 of our 12 patients died from progressive fungal disease. DISCLOSURES: All authors: No reported disclosures.