The antileukemic activity of Bisantrene, a new anthracene derivative, has been evaluated in a phase II clinical study in 10 patients affected by refractory or primary relapsed ANLL. The patients received an induction course consisting of 250 mg/m2/day for 7 days followed, in case of CR, by 250 mg/m2/day for 3 days (consolidation treatment). In case of partial response a reinduction course (250 mg/m2/day for 3 days) was administered. Four out of the 10 patients obtained CR (3 of them after a single induction course). No significant toxic effect was noticed, apart from fever (due to myelosuppression) and hypotension in one patient who soon recovered without residual effects. These preliminary results could suggest further evaluation of Bisantrene in association with other drugs in both relapsed patients and those at onset of the disease.