FDA approves levoleucovorin

摘要

Levoleucovorin for injection, a single-isomer version of the folate analogue leucovorin, has been approved for use as rescue therapy in patients with osteosarcoma treated with high-dose methotrexate, Spectrum Pharmaceuticals Inc. announced March 7.rnThe product is also indicated for reducing the toxic effects of inadvertent overdosage with methotrexate or other folic acid antagonists.rnLeucovorin calcium, a 50:50 racemic mixture of the L- and D-enantiomers of leucovorin, has been sold in the United States for decades. Only the L-isomer of leucovorin has biological activity.rnLevoleucovorin solely consists of the active isomer, and treatment with the drug requires half of the amount used in standard leucovorin therapy, according to the product's FDA-approved labeling.rnThe labeling states that i.v. levoleucovorin administration should begin as soon as possible after an inadvertent methotrexate overdosage. The recommended dosage is 7.5 mg, or approximately 5 mg/m~2, administered every six hours until the patient's serum methotrexate level is less than 10~(-8) M.