The treatment of advanced bladder cancer with methotrexate and cis-platinum--a pharmacokinetic study.

As part of a phase III study in advanced bladder cancer, 5 patients received methotrexate (MTX) 50 mg/m2 as a single agent every 2 weeks, and with every alternate dose of MTX (i.e. every 4 weeks) cis-platinum (CDDP) 50 mg/m2 was given simultaneously, together with saline hydration and diuresis. The clearance of MTX was measured in a total of 12 courses by serial serum sampling for up to 72 hr following injection. In 4 patients (with a mean pretreatment creatinine clearance of 97 ml/min) there was no significant difference between the clearance of MTX when given alone [mean t1/2 (beta) 3.2 hr] and when given 2 weeks later with concurrent CDDP [mean t1/2 (beta) 2.9 hr]. In 1 patient with a pretreatment creatinine clearance of 52 ml/min the clearance of MTX when given alone (without hydration) was significantly delayed compared with the clearance of MTX when given 2 weeks later concurrently with CDDP and saline hydration [t1/2 (beta) 19 and 4.5 hr respectively]. Of the 5 patients so far treated with MTX-CDDP, 2 have had a partial objective response and 3 have had stable disease (including 2 with a marked subjective response). These data indicate that in patients with satisfactory renal function, low-dose MTX and CDDP may be given concurrently without risk of enhanced drug toxicity.