High-dose methotrexate in acute lymphocytic leukemia.

A pharmacokinetic study of methotrexate (MTX) was performed in 60 patients who received high-dose MTX at 500 mg/m2 infused over 24 hours. MTX levels reached 1.2 X 10(-7) M in the cerebrospinal fluid (CSF) within 10 minutes and remained constant at that level for 24 hours. Forty of these 60 patients were children with acute lymphocytic leukemia. In these 40 patients, simultaneous intrathecal MTX was given along with high-dose MTX. The resultant CSF levels (lumbar area) were higher than those obtained with either high-dose MTX alone or simultaneous intrathecal MTX alone. To date, there have been one systemic and one central nervous system relapse in these 40 children, and the treatment program appears safe to administer.