Multilineage response in aplastic anemia patients following long‐term administration of filgrastim (recombinant human granulocyte colony stimulating factor)

Abstract

The present multicenter study was undertaken to confirm whether filgrastim/recombinant human granulocyte colony stimulating factor (rhG‐CSF) could mobilize residual multipotential stem cells by its G_o‐shortening effect in patients with aplastic anemia (AA) and induce a multilineage response. Twenty‐seven patients with acquired severe or moderate AA received long‐term administration (2 to 12+ months) of rhG‐CSF in doses from 100 to 400 ug/body/day by s.c. injection or 250 to 1,500 m̈g/body/day by i.v. infusion. Twenty‐six out of the 27 evaluable patients showed a substantial increase in neutrophils associated with a recovery of myeloid precursors in bone marrow within one month of therapy. Interestingly, 10 out of the 27 patients showed a dramatic improvement in severe anemia after two to ten months of therapy. Moreover, severe thrombocytopenia improved after two to four months of therapy in three out of these ten patients accompanied by a significant increase in megakaryocytes in bone marrow. Clonal cultures of bone marrow cells revealed a recovery in myeloid as well as erythroid precursors in most of these ten patients. In two patients who showed a trilineage response, mixed and megakaryocyte colony formations also recovered. These results suggest that long‐term administration of rhG‐CSF mobilizes myeloid, erythroid, megakaryocyte and multipotential progenitor cells and induces a multilineage response in some patients with AA.