PB2364 UNSUCCESSFUL COLLECTION OF AUTOTRANSPLANT DURING THE FIRST SESSION OF LEUKOCYTAPHERESIS IN PATIENTS WITH MULTIPLE MYELOMA AND EFFECTIVE STEM CELL MOBILIZATION

Abstract

Background:It is well known that the effectiveness of stem cell collection and the possibility to harvest suboptimal CD34+ cells number during the single apheresis session is dependent on the number of CD34+ cells circulating in the peripheral blood (PB), i.e. on the effectiveness of mobilization regimen.Aims:To determine the rate of unseccessful collections in patients with multiple myeloma (MM) when the number of CD34+ cells circulating in the PB is in accordance with the optimal level 20/1 mkl or more.Methods:Retrospective analyses of autotransplant collection in 55 MM patients have been done. Median age of patients was 56 (31‐67) years. Complete response, very good partial response and partial response were diagnosed in 12 (21.8%), 13 (23.6%) and 30 (54,5%) patients accordingly. 25 (45.5%) patients were treated with lenalidomide previously. Cyclophosphamide 3 g/m2 with granulocyte colony‐stimulating factor (G‐CSF) were used for stem cell mobilization in 28 (50.9%) patients. 26 (47.3%) patients were mobilized with vinorelbine 35 mg/m2 with G‐SCF and G‐SCF monotherapy was used in 1 (1.8%) patient.Results:The number of CD34+ cells circulating in PB at the day of the first apheresis procedure was 5‐694/1 mkl (Me 118). Median number of collected CD34+ cells was 5.53 × 10/6/kg (0.27‐29.23). The correlation between number of circulating CD34+ cells and the quantity of harvested CD34+ cells was confirmed: r = 0.503; p < 0.05. At the same time there were 7 (12.7%) cases in which the number of collected CD34+ cells were lower than suboptimal level (0.25‐1.9 × 10/6/kg, Me 1.33 × 10/6/kg) despite the successful mobilization rate: 26‐118/1 mkl (Me 44). The second procedure of apheresis was done on the next day and in all cases except for the one there was the possibility to harvest CD34+ cell number enough to perform a single stem cell transplantation: 2.58‐3.48 × 10/6/kg. The place of central veun catheterization has been changed in all these cases except for the one.Summary/Conclusion:We suppose that a reason of unseccessful stem cell collection in MM patients with adequate rate of mobilization may be disturbance of the bloodstream speed in the apheresis system due to the anatomical characteristics of subclavia vein localization. A method to correct the problem is relief the central catheter puncture place.