Cost and Efficacy of Upfront Plerixafor Versus a “Just-in-Time” (JIT) Approach in Hematopoietic Progenitor Cell (HPC) Mobilization
Authors: Veltri Lauren Westfall , Cumpston Aaron , Shillingburg Alexandra , Lipinski Christopher , Wen Sijin , Leadmon Sonia , Watkins Kathy , Craig Michael David , Hamadani Mehdi , Kanate Abraham S. 
Published: October 2019

Abstract
HPC mobilization with plerixafor (Plex) plus G-CSF (G+P) results in superior CD34+ cell yield, when compared to mobilization with G-CSF alone in patients with myeloma and lymphoid malignancies. However, Plex-based approaches are associated with high mobilization costs. To circumvent higher costs, several institutions use a so-called JIT approach, where Plex is only administered to patients likely to fail mobilization with G-CSF alone. Whether such a JIT-Plex approach is cost effective has not been confirmed to date. We present here, a single institution comparative analysis of 137 patients with myeloma and lymphoma who underwent mobilization with 2 different approaches of Plex utilization. Between Jan 2010-Oct 2012 (n=77) patients received mobilization G-CSF (10 μg/kg) for 5 days and Plex (0.24 mg/kg) on the evening of day four, 11 hours before apheresis the following day (G+P). To reduce mobilization costs between Nov 2012-Jun 2014 (n=60) patients were mobilized with JIT-Plex where Plex was only administered to patients likely to fail mobilization with G-CSF alone (i.e. patients with a day 4 peripheral blood (PB) CD34+ count of <10/μL, or those with day 1 yield of < 1.0 X 106 cells/kg or day 1+2 yield of <1.5 X 106 cells/kg ABW. Mobilization failure was defined as inability to collect at least 2 X 106 /kg CD 34+ cells. Patients in G+P had a higher mean peak PB CD34+ cell count (77 vs. 33.1 cells/μL, p<0.001) and a higher mean CD34+ cell yield on day 1 of collection (4.4 X 106 vs. 2.4 X 106 cells/kg ABW, p=0.0005). The mean total CD34+ cell collection was also higher in G+P (6.64 X 106 vs. 4.81 X 106 cells/kg ABW, p=0.0068). In the JIT-Plex group 41% (n=24) completed adequate HPC collection without Plex. Mobilization failure was noted in 5 patients in the G+P group (3 were salvaged with bone marrow harvest) and 2 patients in the JIT-Plex group. Two patients in either group did not proceed to AHCT as a result of mobilization failure. The mean Plex doses utilized in JIT-Plex was lower (1.3 vs. 2.1, p=0.0002), however 21% (n=16) in the G+P group completed apheresis on day 1 compared to only 6.9% (n=4) in JIT-Plex, p=0.0094. Cost analysis was estimated based on actual sales price (actual wholesale price AWP – (AWP X 0.2)) for mobilization agents and the United states (US) Department of Health and Human Services Centers for Medicaid Services (HHS/CMS) reimbursement rates for procedural costs associated with mobilization, apheresis or cryopreservation. The mean estimated cost was higher in the G+P group ($28,448 vs. $24,852, p=0.0315). Our analyses, for the first time confirms that mobilization with JIT-Plex allows for a safe, adequate and cost efficient strategy for HPC collection.
Baseline Patent Characteristics at Time of Mobilization Table Mobilization Strategy Upfront Plerixafor + G-CSF (n=77) G-CSF + Just-in-time Plerixafor (n=60) p-value Disease Myeloma Lymphoma 46 (60%) 31 (40%) 30 (50%) 30 (50%) 0.29 Mean age, years (range) 58 (23-75) 57 (22-75) 0.45 Male gender 42 (55%) 33 (57%) 0.92 Race: Caucasian 73 (97%) 57 (98%) 1.0 Lines of prior therapy, mean 1.5 1.8 0.3 Prior Radiation 13 (18%) 12 (21%) 0.66 Mean KPS (range) 80 (70-100) 80 (60-100) 0.75 HCT-CI Score (mean) 2 2 0.36
Abbreviations: G-CSF-granulocyte-colony stimulating factor (filgrastim); KPS-Karnofsky performance status; HCT-CI- hematopoietic cell transplantation-specific comorbidity index

Disclosures
No relevant conflicts of interest to declare.