A phase II study of high-dose cytosine arabinoside in the treatment of acute leukaemia in adults.

Twenty-seven adults with refractory or recurrent acute leukaemia were treated with cytosine arabinoside (ara-C) 2 g/m2 infused over 3 h, every 12 h for 6 days, either alone (regimen A) or with vincristine and prednisolone (regimen B). Complete remission was achieved in 9/18 patients (5/12 regimen A, 4/6 regimen B) with acute lymphoblastic leukaemia (ALL), 1/7 patients (1/5 regimen A) with lymphoid blast crisis of chronic myeloid leukaemia (CML.LBC) and 1/2 patients (1/1 regimen B) with acute undifferentiated leukaemia (AUL). A further 5 patients (4 regimen A, 1 regimen B) with ALL, 4 patients (3 regimen A, 1 regimen B) with CML.LBC and 1 patient (regimen A) with AUL showed evidence of significant response. These results confirm the activity of high-dose a-ra-C in acute non-myelogenous leukaemia and suggest that it might be used with benefit to intensify the initial treatment of 'poor-risk' ALL.