Phase I study of high doses of methotrexate with citrovorum factor in patients with lung cancer

A Phase 1 study of high-dose “pulse” methotrexate infusions combined with citrovorum factor “rescue” in advanced lung cancer indicated consistent tumor response in eight patients. A dose schedule allowing for repeated treatments, and thus suitable for prolonged management, was developed. Three patients treated accordingly for 8 to 10 months continue to show regression of their original lesions without evidence of new metastases. These observations are consistent with previously proposed concepts for use of citrovorum “rescue” after administration of high-dose “pulses” of folic acid antagonists.