The Children's Oncology Group study AALL1931 investigated the efficacy and safety of recombinant Erwinia asparaginase (JZP458) in patients with acute lymphoblastic leukemia/lymphoblastic lymphoma and hypersensitivity reactions/silent inactivation to Escherichia coli-derived asparaginases. Each pegylated Escherichia coli asparaginase dose remaining in a patient's treatment plan was replaced by intramuscular (IM) or intravenous (IV) JZP458 (6 doses) administered Monday/Wednesday/Friday (MWF). Three IM cohorts (1a [25 mg/m2 MWF], n=33; 1b [37.5 mg/m2 MWF], n=83; 1c [25/25/50 mg/m2 MWF], n=51) and 1 IV cohort (25/25/50 mg/m2 MWF, n=62) were evaluated. The proportion (95% confidence interval) of patients maintaining nadir serum asparaginase activity (NSAA) levels ≥0.1 IU/mL at the last 72 (primary endpoint) and 48 hours during course 1 was 90% (81, 98) and 96% (90, 100) in IM cohort 1c, respectively, and 40% (26, 54) and 90% (82, 98) in the IV cohort. Population pharmacokinetic modeling results were comparable with observed data, predicting the vast majority of patients would maintain therapeutic NSAA levels when JZP458 is administered IM or IV 25 mg/m2 every 48 hours, or IM 25/25/50 mg/m2 MWF, or with mixed administration of IM and IV (IV/IV/IM 25/25/50 mg/m2 MWF). Drug discontinuation occurred in 23% and 56% of patients in the IM and IV cohorts, respectively; 13% and 33% due to treatment-related adverse events (mainly allergic reactions and pancreatitis). JZP458 achieves therapeutic NSAA levels via multiple IM and IV dosing schedules based on a combination of observed and modeled data with a safety profile consistent with other asparaginases. Clinicaltrials.gov Identifier: NCT04145531.
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