Low-dose etoposide: a potential therapy for myelodysplastic syndromes.

Four patients with refractory anaemia with excess blasts in transformation (RAEB-t) and seven patients with acute leukaemia (AL) transformed from myelodysplastic syndromes (MDS) were treated with etoposide (50 mg, 2 h infusion, two to seven times per week) for at least 4 weeks. Of 10 assessable patients, three RAEB-t patients achieved partial response and one AL patient achieved complete remission. Three of the four responders were resistant to prior repeated low-dose cytarabine therapy. The responders did not require transfusions for 2-9 months while continuing on etoposide therapy. The side-effects were mild and well tolerated. Three possible mechanisms, i.e. a cytotoxic effect, differentiation-induction of malignant cells, and prolongation of blood cell survival by destroying the reticuloendothelial system, may explain the effects of etoposide. We conclude that low-dose etoposide is a potential therapy for MDS and atypical leukaemia.