Use of Glucarpidase for Methotrexate-Induced Nephrotoxicity During the Treatment of Primary Central Nervous System Lymphoma.

High-dose methotrexate (HD-MTX)-based combination chemotherapy remains the mainstay of treatment for primary central nervous system lymphoma (PCNSL). However, MTX-induced nephrotoxicity can occur even with adequate preventive and supportive measures. We report a case of MTX-induced acute kidney injury (AKI) that developed during treatment for PCNSL. During the second course of chemotherapy, serum creatinine increased from 0.74 mg/dL at baseline to 2.15 mg/dL on day 3, accompanied by a peak plasma MTX concentration of 3.89 μmol/L. Following administration of glucarpidase, plasma MTX levels declined to 0.08 μmol/L by day 12, and renal function subsequently improved, with serum creatinine decreasing to 1.47 mg/dL by day 19. This biochemical improvement allowed continuation of MTX-based chemotherapy, and the patient ultimately achieved complete remission after seven courses of treatment. This case highlights the role of glucarpidase in facilitating treatment continuity in the setting of MTX-induced nephrotoxicity and underscores the importance of prompt and appropriate supportive care in the management of PCNSL.