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.