Mobilization of circulating progenitor cells in multiple myeloma during VCAD therapy with or without rhG-CSF.

BACKGROUND Circulating progenitor cells (CPC), when infused in large numbers, rapidly repopulate the marrow after myeloablation with high-dose therapy. In multiple myeloma (MM), as in other disorders, different chemotherapy regimens, including single-as well as multiple-agent chemotherapy, with or without hemopoietic growth factors, have been proposed to mobilize these progenitor cells into the blood. Here we report our experience with a drug combination called VCAD and compare the results to those obtained by adding rhG-CSF to the same combination. METHODS Fourteen MM patients were given one course of VCAD, a chemotherapy association of vincristine 2 mg, cyclophosphamide 4 x 0.5 g/m2, adriamycin 2 x 50 mg/m2 and dexamethasone 4 x 40 mg, before undergoing apheresis to collect CPC for autografting. Seven also received rhG-CSF (filgrastim) 5 mcg/kg/day over the period of apheresis. These latter were allocated to rhG-CSF treatment sequentially from the time the drug became available for clinical use. RESULTS Following VCAD-induced pancytopenia, CFU-GM peaked at a median of 853/mL (range 96-4352; 7.6 times basal level). RhG-CSF administration increased CFU-GM levels but not significantly. With rhG-CSF the CFU-GM peak was reached sooner, toxicity was reduced and granulocytopenia less protracted. Fewer aphereses were run in the rhG-CSF group, there were higher yields per single run, and patients began and completed their collection program more quickly. CONCLUSIONS The VCAD association is able to mobilize CPC in patients with MM, and rhG-CSF is recommended as a fundamental part of the priming schedule.