A Single Center Comparison Between Two Different Apheresis Systems for Peripheral Blood Stem Cell Collections

Introduction: Terumo BCT recently introduced a new system for collecting peripheral blood stem cells (PBSC) with the Spectra Optia® apheresis machine comprising a redesigned disposable kit and an upgraded software version 11.2 (cMNC). This system allows continuous collection of PBSCs, in contrast to the original system where the kit included a chamber for two-step cell separation. The aim of this study was to compare the new cMNC system with the original collection system (MNC) using previously described quality assurance and benchmarking standards [Rosenbaum ER, Wuchter P, et al. Blood (ASH Annual Meeting Abstracts), 2014;124:2458].

Patients and Methods: We performed a retrospective analysis of collection data on 180 patients who underwent PBSC collection between March 2014 and May 2015 at our institution. From March until October 2014 PBSC collection was carried out using the original MNC program with software version 7.2, and from November 2014 the cMNC program with software version 11.2 was used. To achieve a matched comparison, patients were divided into two subgroups according to diagnosis and previous therapy: a homogeneous group of multiple myeloma patients receiving first line therapy (MM group, n=88) and a heterogeneous group of all other patients, including healthy allogeneic stem cell donors (non-MM group, n=92). Patient/donor characteristics are summarized in Table 1. Prediction of the minimum expected CD34+ cells collected /L blood processed was calculated using the formula: (peripheral blood CD34+ cells/µL) × (estimated collection efficiency of 30%) / body weight (kg) [Rosenbaum et al. Cytotherapy, 2012;14:461–466]. To benchmark every LP session, we compared the number of collected CD34+ cells with the predicted number and assessed the performance ratio (collected/predicted CD34+ cells expressed as %).

Results: Overall, 61 MNC and 55 cMNC collection days in the MM group and 56 MNC and 55 cMNC collection days in the non-MM group were evaluated. In the MM group 6.2 and 6.0 ×10⁶ CD34+ cells/kg bw were collected using MNC and cMNC systems, respectively (p=0.194). In the non-MM group 5.8 and 5.4 ×10⁶CD34+ cells/kg bw were collected using MNC and cMNC systems, respectively (p=0.546). The median performance ratio in the MM group receiving first line therapy was 163% with the MNC and 166% with the cMNC system. The median performance ratio in the non-MM group was 137% with the MNC and 125% with the cMNC system. In none of the groups were significant differences in the performance ratio observed for both collection systems (Table 2).  

Conclusions: No significant difference in collection efficiency and performance ratio between the Spectra Optia® MNC system (software version 7.2) and the new cMNC system (software version 11.2) was seen. This supports the notion, that the cMNC system can be implemented without loss of collection efficiency in a broad variety of autologous patients as well as in allogeneic stem cell donors.

Table 1. Patient Characteristics

	MNC	cMNC	P-value
Multiple myeloma
Total patient number	n=47	n=41
Age in years (range)	62 (44-74)	55 (40-70)	0.009
Gender			0.942
Male	n=26	n=23
Female	n=21	n=18
Body weight in kg (range)	79 (54-108)	80 (54-118)	0.722
Non-myeloma
Total patient number	n=48	n=44
Acute myeloid leukemia	n=1	n=0
AL-amyloidosis	n=1	n=4
Allogeneic donors	n=17	n=13
Germ cell tumor	n=2	n=1
Hodgkin lymphoma	n=2	n=2
Multiple sclerosis	n=0	n=1
Non-Hodgkin lymphoma	n=16	n=13
Relapsed multiple myeloma	n=3	n=2
Sarcoma	n=6	n=8
Age in years (range)	47 (18-71)	43 (13-64)	0.582
Gender			0.157
Male	n=31	n=22
Female	n=17	n=22
Body weight in kg (range)	72 (49-106)	74 (50-126)	0.368

Table 2. PBSC Collection Parameters and Daily Collection Results  

	Multiple myeloma			Non-myeloma
Collection regimen	MNC	cMNC	P-value	MNC	cMNC	P-value
Total LP sessions	61	55	-	56	55	-
Peripheral blood CD34+/µl	74 (12-433)	69 (6-336)	0.520	73 (6-1850)	58 (4-862)	0.928
Predicted result (range) in   CD34+ cells ×106 /kg bw	3.76 (0.6-19.4)	3.6 (0.6-14.4)	0.459	4.5 (0.5-55.5)	4.1 (0.3-17.0)	0.637
Collection result (range) in   CD34+ cells ×106 /kg bw	6.2 (1.1-40.4)	6.0 (0.7-16.8)	0.194	5.8 (0.5-43.5)	5.4 (0.3-23.7)	0.546
Performance ratio % (range)   (actual/predicted coll. result)	163 (74-387)	166 (92-251)	0.886	137 (23-309)	125 (28-432)	0.929