Asparaginase Hypersensitivity Reactions in NK/T-Cell Lymphomas.

Background/Objectives: Asparaginase (ASP)-based chemotherapy has substantially improved clinical outcomes in Epstein-Barr virus (EBV)-positive NK/T-cell lymphomas (NKTCL). However, as a bacterial-derived enzyme, ASP is frequently associated with immune-mediated adverse events, particularly hypersensitivity reactions (HSRs), which may compromise both treatment efficacy and patient safety. This report presents a case of an ASP-related HSR and reviews the incidence within our institutional cohort. Detailed Case Description: A 60-year-old female presented an immediate Grade 2 HSR during her second PEG-asparaginase infusion, with pruritus, vomiting, and presyncope. The infusion was discontinued, and she was subsequently transitioned to crisantaspase-an alternative formulation-which was well tolerated without further adverse events. She remains disease-free to date. A retrospective review of institutional records (2015-2025) identified six patients with NKTCL treated with ASP-containing chemotherapy. The incidence of HSRs in this cohort was 1 of 6 (16.7%). Conclusions: As in acute lymphoblastic leukemia, HSRs to asparaginase remains a major challenge in the management of NKTCL with potential implications for treatment safety and efficacy. The establishment of standardized, consensus-based criteria for the diagnosis, classification, and management of ASP-related HSRs is urgently needed to optimize patient outcomes.