Effectiveness of attenuated chemotherapy in myelodysplastic syndromes: a preliminary report

A small group of elderly male patients received attenuated doses of daunomycin, cytosine arabinoside (Ara-C), and 6-thioguanine for treatment of myelodysplastic syndrome (MDS). Three patients had refractory anemia with excess blasts (RAEB), and two had chronic myelomonocytic leukemia (CMMoL). All five patients had developed severe transfusion requirements for platelets and red blood cells before therapy was begun. One patient developed necrosis of the cecum and expired 19 days after therapy, but the other four all showed substantial benefit from treatment. Three of those patients received multiple courses of chemotherapy which led to improvement in peripheral blood counts in each case. Duration of responses as noted by improvement in peripheral blood counts compared to pretreatment levels ranged from 1.5 to 9 months. Despite considerable improvement in peripheral blood parameters, some of the abnormal morphologic features of MDS persisted after each course of chemotherapy. These results obtained with attenuated chemotherapy schedules in a small group of patients are sufficiently encouraging to warrant an expanded phase II trial, which is under way at the University of Rochester Cancer Center.