WASHINGTON -- The FDA has approved the enzyme glucarpidase (Voraxaze) for treatment of toxic levels of the chemotherapy drug methotrexate that build up in the blood because of kidney failure.
The enzyme, given intravenously, breaks down methotrexate rapidly into a form that is eliminated from the body, an FDA statement said.
Kidney failure is not uncommon in patients who receive high doses of methotrexate.
Glucarpidase was approved as an orphan drug, a designation applied to drugs and biologics treating conditions that affect fewer than 200,000 people and which grants the marketer tax and marketing incentives.
The approval was based on two studies, one measuring efficacy, the other safety.
The efficacy study involved 22 patients. Treatment was considered successful if a patient's methotrexate level fell below a critical level within 15 minutes and remained below a critical level for eight days.
Of those treated, 10 patients hit the success benchmark. Treatment eliminated 95% of the methotrexate in all 22 patients.
The safety study evaluated the drug in 290 patients. Adverse events included hypotension, headache, nausea, vomiting, flushing, and abnormal sensation.
The drug is marketed by BTG International.