Half-dose glucarpidase as efficient rescue for toxic methotrexate levels in patients with acute kidney injury.

PURPOSE: High-dose methotrexate (HDMTX)-associated acute kidney injury with delayed MTX clearance has been linked to an excess in MTX-induced toxicities. Glucarpidase is a recombinant enzyme that rapidly hydrolyzes MTX into non-toxic metabolites. The recommended dose of glucarpidase is 50 U/kg, which has never been formally established in a dose finding study in humans. Few case reports, mostly in children, suggest that lower doses of glucarpidase might be equally effective in lowering MTX levels. METHODS: Seven patients with toxic MTX plasma concentrations following HDMTX therapy were treated with half-dose glucarpidase (mean 25 U/kg, range 17-32 U/kg). MTX levels were measured immunologically as well as by liquid chromatography-mass spectrometry (LC-MS). Toxicities were assessed according to National Cancer Institute-Common Terminology Criteria for Adverse Events (CTCAE) v5.0. RESULTS: All patients experienced HDMTX-associated kidney injury (median increase in creatinine levels within 48 h after HDMTX initiation compared to baseline of 251%, range 80-455%) and showed toxic MTX plasma concentrations (range 3.1-182.4 µmol/L) before glucarpidase injection. The drug was administered 42-70 h after HDMTX initiation. Within one day after glucarpidase injection, MTX plasma concentrations decreased by ≥ 97.7% translating into levels of 0.02-2.03 µmol/L. MTX rebound was detected in plasma 42-73 h after glucarpidase initiation, but concentrations remained consistent at < 10 µmol/L. CONCLUSION: Half-dose glucarpidase seems to be effective in lowering MTX levels to concentrations manageable with continued intensified folinic acid rescue.

Treatment of Pegylated Asparaginase-Induced Hypertriglyceridemia with Continuous Intravenous Infusion of Insulin and Heparin: A Case Report.

BACKGROUND: Pegylated asparaginase may induce prolonged hypertriglyceridemia. To date, there is no standard management of this complication. Here, we present a case report of pegylated asparaginase-induced hypertriglyceridemia and hepatotoxicity successfully treated with continuous intravenous infusion of insulin and heparin. CASE PRESENTATION: A 51-year-old male patient with lymphoid blast crisis of chronic myelogenous leukemia was treated with pegylated asparaginase. The patient developed severe hypertriglyceridemia. Supportive therapy with low-fat diet, fibric acids, and omega-3 fatty acids was not successful, and later, the patient developed high-grade hepatotoxicity. Like hypertriglyceridemia-induced pancreatitis, continuous intravenous infusion of insulin and heparin was initiated. The level of triglyceride and cholesterol decreased rapidly within 4 days. CONCLUSION: In case of severe pegylated asparaginase-induced hypertriglyceridemia, continuous intravenous infusion of insulin and heparin can reduce rapidly and safely the triglyceride level. Controlled trials are needed to address this important issue.