Effects of CSFs in preleukemia.

Based on pre-clinical and in vitro studies demonstrating enhanced granulocytic proliferation and differentiation induced by granulocyte-monocyte and granulocyte-colony stimulating factors (GM-CSF and G-CSF), these recombinant human hormones have been used to treat cytopenic patients with preleukemia [i.e., myelodysplastic syndromes (MDS)]. To date, five studies have been reported using GM-CSF short-term (generally 7-14 days, x 1-5 courses). Thirty-eight of 45 treated patients had improvements in neutrophil counts, 14 had increased reticulocyte counts with three of these individuals having decreased RBC transfusion requirements, and eight had transient increases in platelets. In 12 patients an increase in marrow and/or peripheral blood blasts was noted. Seven patients progressed to acute myeloid leukemia (AML), particularly patients with greater than 15% marrow blasts. In a longer term study, five patients received GM-CSF for 2 to 9 weeks, although only one individual maintained increased neutrophil counts, one developed antibodies to GM-CSF and one evolved into AML. Eighteen patients have been treated for 2 months with G-CSF, 16 of whom had normalization of neutrophil counts with improved marrow maturation, five had increased reticulocyte counts with three having decreased transfusion requirements, no substantial changes in platelet counts were noted. Eleven patients have received maintenance therapy with G-CSF for 6-16 months, ten had persistent increases in neutrophil counts with enhanced marrow myeloid maturation and five had increased reticulocytes. Decreased infectious episodes were notedat times of neutrophil improvements. Four of the 18 individuals have subsequently developed AML after 6-16 months.(ABSTRACT TRUNCATED AT 250 WORDS)