Cyclophosphamide (NSC-26271) maintenance therapy after a second remission of childhood acute lymphoblastic leukemia: comparative clinical trial (standard dose versus intermittent high dose versus cyclophosphamide plus cytosine arabinoside (NSC-63878)).

Children with acute lymphoblastic leukemia who had experienced only one relapse were reinduced into remission using a 6-week induction course of prednisone and vincristine. One hundred fifty-one children who achieved a second complete marrow remission were randomly assigned to one of three cyclophosphamide treatment groups for maintanence. Forty-one children received standard-dose cyclophosphamide (3 mg/kg/day), 55 received intermittent high-dose cyclophosphamide (10 mg/kg/day for 4 days out of 14), and 55 received a combination of oral cyclophosphamide (3 mg/kg/day) plus cytosine arabinoside (3 mg/kg/week im). The standard-dose cyclophosphamide regimen resulted in a remission maintenance time of 109 days and was the least toxic of the three maintenance regimens. Giving cyclophosphamide on an intermittent high-dose schedule or combining it with cytosine arabinoside did not increase the remission maintanence time (105 days).