Patients suffering from high-risk multiple myeloma (MM) were randomized to receive single high-dose cyclophosphamide followed by either rhGM-CSF or rhG-CSF in order to harvest circulating peripheral blood progenitor cells. The safety of the procedure, the mobilization kinetics, the relative efficacy of rhGM-CSF and rhG-CSF to mobilize progenitor cells and their relative toxicity were studied. Special attention was paid to the antigenic profile of CD34 sup + progenitor cells.
Group I patients (n=11) were treated with cyclophosphamide 4 g/m sup 2 i.v. followed by rhGM-CSF at 10 microgram/kg/d by subcutaneous administration. Group II (n=11) patients received rhG-CSF s.c. at 10 microgram/kg/d after the same dose cyclophosphamide. Both mobilization regimens appeared to be equally effective. No significant differences in absolute numbers of circulating progenitors, determined by CD34 expression or in yields of MNC, CFU-GM, BFU-E and CD34 subsets were observed. rhGM-CSF administration resulted however in delayed haemopoietic recovery and an increased complication rate.
We conclude that rhG-CSF may be preferred because of its markedly lower toxicity and lower in-hospital costs.