Twenty-two patients (mean age 41 years) in blast crisis or accelerated phase (AP) of chronic myelogenous leukemia (CML) were treated with cytosine arabinoside (Ara-C) 500 mg/m2 [intermediate dose] or 1000 mg/m2 [high dose] twice a day for 6 days and amsacrine (AMSA) 120 mg/m2 for 3 days. Twenty-one cases were of myeloid type and one was a lymphoid BC. The mean duration of aplasia (neutrophils < 0.5 x 10(9)/l) was 21.5 days. Four patients (18%) died of infection during aplasia and minor toxicities were noted for the remainders. Nine patients (41%) achieved a complete remission (CR) and 4 (18%) a partial response. Various additional therapies were proposed after induction treatment including allogeneic bone marrow transplantation (2 patients), Ara-C and AMSA maintenance or other regimens with or without alpha-interferon (9 patients). Median survival for the entire cohort was 20 weeks (wks), significantly superior for complete responders (37 wks) than for others (7 wks) (p = 0.008). In this study, age, sex, initial platelet or basophil counts, interval between diagnosis of CML and blast crisis were not predictive of response. Although inducing a high CR rate and associated with acceptable toxicity, this regimen did not improve the survival of patients with BC or CML, strengthening the need for alternate approaches to be defined.