MOBILIZATION OF PERIPHERAL BLOOD PROGENITORS IN MULTIPLE MYELOMA. HOW TO DEAL WITH HARD TO MOBILIZE MYELOMA PATIENTS-SIX YEARS CENTER EXPERIENCE

Abstract

Peripheral blood progenitor cells (PBPCs) mobilized with high-dose chemotherapy and hematopoietic growth factors are still used to support myeloablative therapy of multiple myeloma during the autologous setting. Variables having an impact on the ability to collect PBPC include age, month’s prior previous chemotherapy, mobilization regimen and platelet count at the time of mobilization. Myeloma patients with low mobilizing capacity indicate the need of evaluating alternative mobilizing regimens. We analyzed 25 patients with MM that underwent PBPC mobilization at Department of hematology, University Clinical Center Skopje. Pts received Cyclophosphamide (3gr/m2) followed by daily G-CSF (10 mcg/kg). In 15 pts we experienced a significant WBC nadir on median day +6, and began pheresis in recovered WBC up to 5.0×109/L on day +8 (median). Good mobilizers reached at least 2×106/kg CD34+ cells with median 3 (ranges 1-6) apheresis procedures. In 9 MM patients we registered low mobilizing capacity. Remobilizing procedure was preformed with single G-CSF in a dose of 20 mcg/kg in a 5 days regimen. All remobilized patients reached sufficient CD34+/kg count with median 2 (ranges 1-4) aphaeresis procedures. In statistical data in both groups of good and hard to mobilize MM pts we followed several variables concerning the platelet count on day 1 of aphaeresis which correlated with the ability to collect over 5×106 CD34+cells/kg (p<0,001), age of patients < 60 yrs and >60yrs (p<0,001) and previously received chemotherapy cycles of 5 pts (27%) who started aphaeresis on median day +14 (p<0,001) in the Cy/G-CSF group. We can conclude that the 5 day regimen of single G-CSF in increased daily dose showed effective with efficient yields results for median 2 day leukopheresis procedure, well tolerated with possibility for mobilization in outpatient basis. This approach, if confirmed on larger series of myeloma patients could open new opportunities in stem cell mobilization for poor or non-mobilizers.