Glucarpidase Criteria For Use

Osteosarcoma patients:

• Methotrexate level >50 micromole at hour 24, > 10 micromole at hour 36, >5 micromole at hour 48
• OR plasma levels >2 standard deviations above the mean methotrexate elimination curve at >12 hours
• AND SCr >2 times above pre-methotrexate baseline

Other patients:

• Methotrexate level >5 micromole for >42 hours post-methotrexate initiation
• OR plasma levels >2 standard deviations above the mean methotrexate elimination curve at >12 hours
• AND SCr >1.5 times above pre-methotrexate baseline OR SCr >1.8 mg/dL

Dose: 50 units/kg IV as a single dose over 5 minutes

• Administer within 96 hours of initiating the methotrexate infusion.
• Do not administer leucovorin within 2 hours of glucarpidase.
• For 48 hours after glucarpidase administration, determine the leucovorin dose based on the patient’s pre-glucarpidase methotrexate concentration.