Combined VM-26 and cytosine arabinoside in treatment of refractory childhood lymphocytic leukemia.

On the basis of previous findings at this institution, VM-26 and Cytosine Arabinoside (ara-C) were used in combination to treat 33 children with refractory acute lymphocytic leukemia (ALL). Chemotherapy was given by vein twice a week for four weeks at dosage of 300 mg/m2 for ara-C and 50, 75, 110, 165, or 200 mg/m2 for VM-26. Ten marrow remissions (nine complete and one partial) were induced, with hypotension (2/33) and bone marrow hypoplasia (20/33) the most significant side effects observed. Therapeutic responses were obtained with each dosage of VM-26 except 75 mg/m2; myelosuppression developed at all dosages, being most prolonged at 200 mg/m2. Ten of the 23 non-responders did not complete their planned courses of therapy. The significance of this information is that combinations of VM-26 and ara-C were effective in patients who were either in late stages of their leukemia or had never achieved an initial remission. All had been previously treated with prednisone, vincristine, daunomycin and L-asparaginase. In addition, seven of the 10 responders had previously received ara-C in other drug combinations. The use of VM-26 and ara-C in combination may be warranted for newly diagnosed patients who are at high risk for treatment failure with first-line drugs.