Value and Cost Effectiveness of Storing Peripheral Blood Progenitor Cells for Salvage Autologous Stem Cell Transplant in Multiple Myeloma

Abstract

<h3>Introduction</h3> Salvage autologous stem cell transplant (sASCT) may be associated with improved survival in multiple myeloma (MM) and is an option for patients with long time to relapse (TTR) after initial Autologous transplant (ASCT1). Due to potential mobilization failure after maintenance therapy (MT), adequate peripheral blood progenitor cells (PBPC) are frequently collected for later sASCT. <h3>Objectives</h3> Evaluate utilization of stored PBPC in MM. Provide a cost analysis of collecting and storing PBPC for sASCT. Determine utilization of sASCT in those eligible who had a prolonged TTR. <h3>Methods</h3> We included MM patients who received ASCT1 at our institution between 2009 and 2016. Extra day of collection (EDC) was defined as additional collection of ≥2 × 10⁶ cells/kg PBPC for a second transplant. TTR was calculated as months from ASCT1 to relapse. Eligibility for sASCT was defined as TTR ≥18 months without MT or ≥36 months on MT. Patients who underwent tandem transplant (tASCT) (defined as two transplants within 6 months) were excluded from relapse analysis. Patients with inadequate relapse data defined as death or lost to follow up (LTFU) at ≤36 months prior to relapse, or ≤6 months follow up after relapse were excluded. Costs were obtained from the institution charge master. Descriptive statistics were calculated for the final cost benefit analysis. <h3>Results</h3> 154 MM patients received ASCT1 from 2009-2016. Median age was 59 years. Median follow up was 151 months. Median TTR was 20 months. 58% were male. Ethnicity was 76% Caucasian and 24% Black. 62% had IgG MM subtype, 23% IgA MM and 15% other. Majority (95%) were European Cooperative Oncology Group (ECOG) 0 or 1. 13% had high risk cytogenetics. 53% received MT. 137(89%) had PBSC stored for sASCT. 3 were used for sASCT and 10 for tASCT. 124 (90.5%) did not use stored cells. 54 (39%) met collection targets for two transplants in single collection while 83 (%) required ≥1 EDC with cumulative 108 EDC. (Figure 1) Cumulative cost savings for plerixafor use, cell collection, processing, analysis and storage was estimated at $2,252,244. (Figure 2). Total 60 doses of plerixafor were used for EDC. (31 patients with 1EDC, 10 with 2EDC and 3 with 3 EDC). 97 patients were studied for relapses. 54 (77.5%) relapsed. 5 deaths and 8 LTFU occurred within ≤6 months of relapse. 42 patients were further analyzed. 25 of them met criteria for sASCT based on TTR and only 2 received sASCT.1 patient with sASCT did not have MT data and was excluded. (Figure 3) <h3>Conclusion</h3> Only 25% (24/98) patients who underwent ASCT1 were eligible for sASCT. Only 2% (2/98) received sASCT. Collecting and storing PBPC for sASCT is associated with high cost, but overall utilization at our institution is low. Our findings should be compared against practices at other institutions to help develop guidelines for selection of subset of MM where this practice may be of higher value.