Growth factor administration following autologous peripheral blood progenitor cell transplantation.

Hematopoietic growth factor (HGF) administration following autologous peripheral blood progenitor cell transplantation (APBPCT) is a current approach for shortening the duration of high-dose chemotherapy-induced transient peripheral pancytopenia. Several published clinical experiences and a retrospective study reported here show that recombinant human granulocyte colony stimulating factor (rhG-CSF) or recombinant human granulocyte-macrophage colony stimulating factor (rhGM-CSF) administration potentiates polymorphonuclear leukocyte (PMN) and white blood cell (WBC) recovery with some clinical benefits mainly related to the reduction of infectious complications during the shortened period of neutropenia. However, this therapeutic strategy does not produce any enhancement of platelet (PLT) recovery or potentiation of red cell production. Conversely, a recent phase I/II study carried out in our institution showed that the combined administration of rhG-CSF and recombinant human erythropoietin (rhEPO) is able to potentiate trilineage hematopoietic recovery with a reduction of PLT transfusions and to considerably simplify the clinical management of patients as compared to patients treated with APBPCT alone. The post-APBPCT administration of rhEPO with rhGM-CSF decreased the number of days with WBC < 1 x 10(9)/L but failed to produce any appreciable effect on PLT recovery. Both combined treatments significantly reduced the patients' hospital stay and allowed the abrogation of systemic antibiotic administration following APBPCT. A further group of patients were treated with the combined administration of rhEPO, rhG-CSF and rhGM-CSF; they did not show a faster hematopoietic recovery than rhG-CSF plus EPO treated patients and a consistent hyperthermia was observed in most patients as a prominent side effect. Future prospective randomized studies will clarify the efficacy of HGF administration following APBPCT. Moreover, further improvements in the hematopoietic support of transplanted patients may be obtained when stem cell factor, flt3/flk2 tyrosine kinase ligands or megakaryocyte growth and development factor will become clinically available.