Intermediate-dose cyclophosphamide and granulocyte colony-stimulating factor is a valid alternative to high-dose cyclophosphamide for mobilizing peripheral blood CD34+ cells in patients with multiple myeloma.
Peripheral blood stem cells (PBSC) are widely used in the setting of dose-intensive chemotherapies in patients with multiple myeloma (MM). Although the granulocyte colony-stimulating factor (G-CSF), following chemotherapy or not, is considered the standard growth factor for mobilizing PBSC, the optimal chemotherapeutic regimen still remains to be defined. Cyclophosphamide (CTX) is an effective drug in the treatment of MM which is capable of mobilizing PBSC if followed by growth factors, even though administration of high-dose CTX (7 g/m(2)) results in severe toxicity requiring hospitalization and increasing costs. We have retrospectively analyzed the results obtained in 38 newly diagnosed MM patients treated with 1.2 g/m(2) CTX on days 1 and 3 combined with 40 mg dexamethasone daily for 4 days. The results were compared with those obtained in 25 newly diagnosed MM patients treated with 7 g/m(2) CTX. A higher number of CD34+ cells/kg was collected during the first leukapheresis and a statistically significant lower consumption of G-CSF was observed following two doses of 1.2 g/m(2) CTX compared to the 7 g/m(2) CTX dose. The possibility of treating patients with day-hospital regimens, with a satisfactory yield of hematopoietic cells harvested, may have relevant economic implications for treatment strategies in MM patients.