Predictors of Stem Cell Yield Via Apheresis in Patients Undergoing Stem Cell Mobilization,
Authors: Saliba Rima M , Chiattone Alexandre , Majlis Alejandro , Chiattone Viviane C. , Rondon Gabriela , Sakashita Araci M. , Hamerschlak Nelson , Kutner Jose Mauro , Shpall Elizabeth J , Anderlini Paolo , Khouri Issa , Qazilbash Muzaffar H , Popat Uday , Champlin Richard , Hosing Chitra M , De Lima Marcos 
Published: October 2019

Abstract
Abstract 4058
Stratification models for prediction of the likelihood of success of peripheral blood stem cell collection via apheresis in patients are lacking. Peripheral blood (PB) CD34+ cells concentration ([CD34+]) pre-apheresis, and blood volume processed (BVP) have been shown to predict the CD34+ cell dose collected on the first day of apheresis (Pierelli et al Vox Sanguinis 2006, 91; 126). We sought to determine the predictive value of these factors, in addition to other mobilization and patient characteristics, in a total 851 consecutive autologous apheresis procedures performed at M.D. Anderson Cancer Center between 01/05–12/09. Patients and Methods: Baseline patient characteristics considered include age, gender, weight, diagnosis, complete blood counts on day of collection, and the absolute PB CD34+ counts within 24 hours of the first apheresis procedure. The study population was randomly divided into equal study (n=425) and validation (n=426) samples. Results: We report results of analyses performed on the study sample which included 241 Multiple Myeloma patients (pts), 135 Non-Hodgkin's Lymphoma pts, and 49 Hodgkin's pts. Logistic regression analysis was used to evaluate the association between CD34+ collected dose > 2 × 106/Kg (available for 401/425 pts) and BVP (L); BVP/Kg; pre-apheresis blood counts including [CD34+], Hemoglobin level (≤10 vs. >10 g/dL), WBC (<4 vs. >4 x109/L), absolute neutrophil count [ANC] (< vs.≥ median), and platelet count (≤150 vs. <150 x109/L); days to first apheresis procedure from start of mobilization regimen (< vs. ≥ median); patient's age (quartiles) and gender; and diagnosis. On univariate analysis, pre-apheresis [CD34+] count was the most significant predictor of CD34+ dose collected on the first day of apheresis (graph). Ninety-six percent of patients with [CD34+] >40/μL (n=158) collected >2 x106CD34+ cells/Kg, while only 8% of those with [CD34+] ≤ 10/μL (n=25) reached that target. The proportion of patients who collected >2 x106CD34+ cells/Kg increased from 15% to 67% with increasing [CD34+] counts ranging between11–40/μL (n=218). Additional significant predictors of higher CD34+ dose collected in this group of pts (n=218) included larger BVP/Kg (>0.2 L/Kg, n=50, p<0.001), shorter than the median duration from start of mobilization to the first apheresis procedure (n=122, p<0.001), and male gender (n=128, p 0.01). Low Hemoglobin (n=42, p 0.007), low WBC (n=69, p 0.02), low platelet count (n=41, p 0.02), age >60 yrs (n=90, p0.06), and NHL histology (n=56, p 0.02) were associated with collection of lower CD34+yield/Kg. There was no impact of patient's weight or ANC. Multivariate analyses are ongoing to evaluate the independent prognostic value of these predictors. The resulting model will be validated in an independent sample. Conclusion: Patients whose pre-apheresis absolute CD34+ counts are between 11–40/μL may be able to collect a higher CD34+ cell dose/Kg on the first day of stem cell collection if higher blood volume is processed, especially patients who took longer to mobilize.Table:ABS PRE APHERESIS CD34 between 11–40/μL (N=218)N>2 X106/Kg CD34 D1OR95% CIP valueFinal pre-apheresis CD34+ count/μL    11–155915%Ref.    16–258831%2.41.06–5.70.04    25–302952%5.92.1–160.001    31–404267%114.3–29<0.001BVP, L, Day 1 quartiles    146333%Ref.    >14–165240%1.30.6–2.90.4    >16–185437%1.20.5–2.50.7    >184736%1.10.5–2.50.8BVP, L/Kg, Day 1, quartiles    ≤ 0.216631Ref    >0.250562.91.5–7.70.001*Days on GCSF <med    Yes8716%5.52.8–10.8<0.001    No11951%Combination days on G-CSF/BV    Fewer days G-CSF/High BVP3266%Ref.    Fewer days G-CSF/Low BVP8746%0.40.2–1.030.06    More days on G-CSF/High BVP1533%0.30.1–0.90.04    More days on G-CSF/Low BVP7113%0.10.03–0.2<0.001Age, years    ≤ 6012841%Ref.    >609029%0.60.3–1.020.06Labs Before starting mobilizationHgb g/dL, quartiles    ≤104221%0.40.2–0.80.007    >1017339%Ref.WBC x109/L, quartiles    <46919%0.20.05–0.70.02    ≥ 414644%Ref.PLT x109/L, quartiles    ≤1504119%0.40.2–0.80.02    >15017440%RefWBC Day 1 apheresis    ≤median10424%0.30.2–0.6<0.001    >median11447%Diagnosis    Non-Hodgkin's lymphoma5623%0.40.2–0.90.02    Hodgkin's1937%0.80.3–2.20.7    Multiple Myeloma14341%Ref.Gender    Female9027%0.50.3–0.90.01    Male12843%Ref.

Disclosures:
No relevant conflicts of interest to declare.