Bilineage response in refractory aplastic anemia patients following long‐term administration of recombinant human granulocyte colony‐stimulating factor

Abstract

5 patients with refractory aplastic anemia (AA) received long‐term administration (2–11 + months) of recombinant human G‐CSF (rhG‐CSF) in doses from 250–500 μg/body/day by intravenous infusion or 75–300 μg/body/d by subcutaneous injection. All 5 evaluable patients showed a substantial increase in absolute neutrophil count (ANC) with a recovery of myeloid components in the bone marrow after 1 to 2 months of treatment. Interestingly, 2 out of the 5 patients showed a dramatic improvement in severe anemia after 2 to 4 months of treatment accompanying a recovery of erythroid components in the bone marrow. In addition, there was no serious infection before or during therapy. Long‐term administration of rhG‐CSF was well tolerated because of its minimal toxicity. Clonal assay revealed a recovery of myeloid progenitors in all patients and a recovery of erythroid progenitors in 3 out of the 5 patients. These results suggest that long‐term administration of rhG‐CSF at least mobilizes residual myeloid as well as erythroid progenitor cells and induces a bilineage response in severe refractory AA.