A Single Centre Analysis of Spectra Optia Stem Cell Collection Data from Multiple Myeloma and Lymphoma Patients, with and without Plerixafor
Authors: Buckley Joy , Krawczyk Janusz , Ni Chonchubhair Fionnuala , Besson Nelly , Tarpey Margaret , Murray Margaret , O'Dwyer Michael C , Hayat Amjad 
Published: October 2019

Abstract
Introduction:
The Spectra Optia Apheresis System has been in use in our centre for 3 years for the collection of autologous peripheral blood stem cells (PBSC).We compared the Collection Efficiency (CE2) of the two Optias we have in use and also compared the CE2 of patients with Multiple Myeloma (MM) and Lymphomas, and those mobilised with and without Plerixafor. The Collection Efficiency (CE2) is calculated as follows: (Total CD34+ collected)/ (Whole Blood volume processed x Pre-CD34+ count). It is a crude estimation of the potential yield of a harvest and assumes that the CD34+ concentration is constant throughout a procedure. As the concentration of CD34+ cells in the peripheral blood will naturally drop off during a procedure, the CE2 can be expected to give a result that underestimates the yield. The pre-harvest FBC would normally be taken about 3 hours prior to commencement of the harvest, thus the peripheral CD34 may not fully reflect the count immediately before starting the harvest and this may also influence the accuracy of the CE2 result.
Patients and Methods:
Data on 143 peripheral blood autologous stem cell harvests from 87 patients collected using the Spectra Optia from mid-2011 to mid-2014 have been examined. Procedures without pre-harvest CD34+ counts or incomplete were excluded from the analysis. Procedures included in the analysis (138) are summarised in table 1. Median age of patients was 59 years (range 26-69). All patients were mobilised using disease specific standard protocols. Patients who fail to mobilise by the expected date were frequently given Plerixafor. A CD34+ dose of 5 x 106/kg was used as desirable target for reinfusion with enough for two reinfusion collected for MM patients to allow for repeat reinfusion if required.
Statistical Analysis:
Statistical analysis was performed using SPSS package. We have compared the CE2 achieved by each Optia machine, the CE2 results of the 2 main diseases MM and Lymphomas and to determine if any difference in Collection Efficiency is evident when patients are mobilised using Plerixafor.
Results:
143 collections were included in the analysis. Fifty patients underwent one collection, 27 patients underwent two collections, and 10 patients required three collections to achieve the minimum CD34+ cell dose required. The mean CE2 for the entire cohort was 74.23% and mean CD34+ yield was 4.6 x 106/kg/collection. There were no statistically significant differences in pre-collection CD34+ count, collection efficiencies and final CD34+ yield between groups according to instruments used, administration of Plerixafor and diseases (Table 1). A significant correlation between the Preleukapheresis peripheral blood CD34+ cell count and the CD34+ cell yield of each leukapheresis was shown by a linear regression analysis (r2 = 0.867, p < 0.0001; Figure 1).
Conclusions:
For maximisation of PBSC yield, the timing for PBSC collection after these mobilizations is critical. Among criteria utilized to predict yield, the circulating peripheral blood CD34+ cell count has been a good predictor of PBSC yield mobilized with protocols used in our centre. In our data, pre-leukapheresis peripheral blood CD34+ cell count on the day of collection correlates with the final CD34+ yield. Interestingly, administration of Plerixafor in patients clinically at risk of poor mobilisation allows collection of comparable quality to patients who mobilised without Plerixafor.
Abstract 3848. Table 1. Characterisation of collections, including device used, disease indication and use of Plerixafor. CD34_CE2 Periph_cd34 Actual yield Mean SD Number of procedures Mean SD Number of procedures Mean SD Number of procedures Optia 1 80.89% 85.37% 62 51.8 43.9 62 4.733 4.379 62 2 68.69% 17.38% 73 49.7 48.4 73 4.630 3.834 73 disease lymphoma 73.66% 28.94% 57 51.1 57.2 57 4.581 4.608 57 myeloma 75.39% 76.69% 73 52.7 36.5 73 5.008 3.651 73 other 65.45% 11.13% 5 15.4 12.0 5 .945 .677 5 Plerixafor no 73.79% 64.18% 107 55.1 47.6 107 5.078 4.208 107 yes 76.19% 35.77% 28 33.7 36.6 28 3.144 3.155 28 Total 74% 135 50.60 46.20 135 4.680 4.080 135
Fig. 1. Relation between pre-leukapheresis CD34+ count and actual leukapheresis yield. Fig. 1. Relation between pre-leukapheresis CD34+ count and actual leukapheresis yield.

Disclosures
No relevant conflicts of interest to declare.