[Results and pharmacokinetic aspects of methotrexate therapy in high doses]

We used MTX as single drug treatment on the basis of an incremental dosage schedule, with doses increased from 250 mg/m2 to 750 mg/m2 or from 5 to 10 g, at intervals of 10 days. Moderately high MTX doses (750 mg/m2 at most) plus citrovorum factor rescue, failed to result in objective tumor regression in all of the 18 patients thus treated. High-dose MTX with CF rescue, by contrast, was found to produce partial remissions in 3 of the 19 cases treated thus far. Meticulous clinical monitoring and MTX serum level determinations are imperative for minimizing complications, if this drastic treatment regimen is employed.