[Methotrexate-leucovorin rescue therapy: pharmacological characteristics and clinical effective use].

An antifolate first introduced into the clinic about half decades ago, Methotrexate is effective against a variety of human cancers, when administered alone or in combination with leucovorin rescue at wide-ranging doses and by many different schedules. We know much more about MTX and its molecular and cellular pharmacology and mechanisms of anti-cancer action in light of current knowledge of the biochemistry of folate. This understanding has stimulated novel approaches to the clinical application of the drug and has greatly enhanced its therapeutic efficacy.