In a phase II study, 21 patients with MDS (
RAEB, RAEBt, CMML and RA and RAS with severe
cytopenia) were randomized to be treated with 3 courses of
GM-CSF (3 micrograms/kg/day s.c.) alone (11 patients) or in combination with AraC (20 mg/m2/d s.c.) (10 patients) for 14-d periods, interrupted by 14-d rest periods. Eight patients discontinued the treatment. In the
GM-CSF group a marked increase in WBC and neutrophil counts during each course of treatment administration were seen in most patients. Platelet counts decreased in 14 of 24 courses of treatment in the
GM-CSF plus AraC group but in none of the
GM-CSF group. Although the changes in the circulating blood cells were transient and the counts tended to return to the pretreatment levels during the rest periods, some more durable effects were seen. In 3/6 patients of the
GM-CSF group who completed the designed treatment, both WBC and neutrophils remained elevated above the pretreatment levels throughout the 3-month period of treatment, while in one of them
thrombocytopenia improved considerably. In the
GM-CSF plus AraC group, 4 out of the 7 patients who completed the treatment showed an improvement of
neutropenia as well as anaemia. In these 4 patients the BM percentage of blasts was also decreased. In conclusion, the results of this study indicate that
GM-CSF given intermittently improves
leukopenia in some patients with MDS. In addition, the administration of
GM-CSF seems to prevent
granulocytopenia of concurrent AraC treatment and may be of benefit in the treatment of these diseases.