Treatment of acute lymphocytic leukemia by high-dose intravenous methotrexate.

A pharmacokinetic study of methotrexate levels in blood and cerebrospinal fluid was performed in 42 patients who received one or more courses of high-dose methotrexate at 500 mg/sq m infused i.v. over a 24-hr period. Methotrexate level in the lumbar cerebrospinal fluid reached 1.2 x 10(-7) M at 0.5 hr and remained constant at that level for the 1st 24 hr. Similar methotrexate levels were noted in the ventricular fluid obtained through an Ommaya device on three patients with brain tumors treated with high doses of methotrexate. Preliminary clinical results using high-dose methotrexate combined with simultaneous intrathecal methotrexate in 23 children with newly diagnosed acute lymphocytic leukemia indicate that this treatment program is safe to administer and to date appears effective in the prevention of central nervous system leukemia.