Impact of Dosing Interval Adherence on Pharmacokinetic Outcomes of Recombinant <i>Erwinia</i> Asparaginase in Pediatric Leukemia or Lymphoma

INTRODUCTION: Treatment for pediatric acute lymphoblastic leukemia includes asparaginase as an integral component of therapy. Hypersensitivity reactions or silent inactivation to Escherichia coli (E. coli) formulations may necessitate switching to Erwinia-based asparaginase (asparaginase Erwinia chrysanthemi [E-ASP] or recombinant asparaginase Erwinia chrysanthemi [R-ASP]). However, pharmacokinetic data for R-ASP in pediatrics remain limited, and recommended dosing schedules present logistical challenges. We investigated if adherence to approved dosing regimens for R-ASP is necessary to achieve optimal pharmacokinetic exposure in pediatric patients with leukemia or lymphoma. METHODS: We performed a single institution, retrospective review of pharmacokinetic data in patients who received R-ASP between October 1, 2021 and September 30, 2024. A one-compartment pharmacokinetic model with first-order absorption and elimination was used to evaluate asparaginase pharmacokinetic activity. The pharmacokinetic model was used to determine if the labeled dosing window for R-ASP is required to achieve effective asparagine depletion. RESULTS: administered intramuscularly on a Monday, Wednesday, and Friday dosing schedule. CONCLUSION: Overall, our findings support the importance of adhering closely to the United States Food and Drug Administration approved dosing schedule for R-ASP to ensure adequate asparaginase activity in pediatric patients with leukemia or lymphoma.