The Use of Amsacrine plus Intermediate-Dose Cytosine Arabinoside in Relapsed and Refractory Acute Nonlymphocytic Leukemia

In a previous study [1] we found that cytosine arabinoside (Ara-C) in an intermediate dose of 500 mg/m2 every 12 h for 6 days was an effective therapy with only a mild degree of toxicity in not heavily pretreated patients with acute nonlymphocytic leukemia (ANLL). This dose was calculated to be sufficient for saturation of the phosphorylating enzymes. Amsacrine (AMSA) monotherapy appears to be active in refractory or relapsed ANLL [2]. In this study we investigated the efficacy and toxicity of a combined regimen of Ara-C with AMSA in 27 patients with relapsed or refractory ANLL or myeloid blas-tic crisis of chronic myeloid leukemia (CML). The remission induction therapy consisted of the optimal dose schedule for AMSA, 150 mg/m2 every 24 h [2], and Ara-C, 500 mg/m2 every 12 h for 5 days each [1]. The same combination was used as consolidation treatment but only for 3 days. Patients were evaluated for response using the standard criteria of the Cancer and Acute leukemia Group B (CALGB). Toxicity was evaluated according to the WHO criteria [3].