LAUSR

Autologous stem cell transplantation (ASCT1) plays an important role in the management of patients with multiple myeloma (MM) and remains relevant in the era of novel therapeutics [1, 2]. A second autologous transplant, usually after reinduction therapy, is a recommended strategy at the time of relapse, with improved progression-free survival (PFS) and possibly improved overall survival (OS) in select patients compared to chemotherapy in some series [3–5]. Due to potential difficulties harvesting adequate peripheral blood stem cells (PBSC) at the time of relapse and published clinical guidelines our institutional policy has been to collect and cryopreserve sufficient hematopoietic progenitor cells whenever feasible to allow for salvage transplant (ASCT2) at the time of relapse. The utilization of salvage autologous transplants and associated costs were analyzed in a cohort of 169 MM patients who received ASCT1 between January 2009 and December 2017. We focus, in particular on the subgroup of patients who met the mSMART criteria for ASCT2 defined as relapse >36 months with the use of maintenance therapy or 18 months without the use of maintenance therapy, respectively [6]. Patient demographic data, disease-related information, and cellular therapy data were obtained from institutional databases, the Stem Soft Database and chart review. Follow-up was until death or last contact with the data cutoff being January 1, 2020. Patients were censored at their last visit if they were lost to follow-up. This study was approved by the Institutional Review Board at University Hospitals, Cleveland Medical Center, and due to the nature of the study, patient consent was not required. ASCT2 was offered based on patient and physician preference. PBSC were mobilized using cyclophosphamide (2–4 gm/ m) plus filgrastim (n= 24), filgrastim at a dose of 10–16 μgm/kg with leukapheresis starting on day 5 (n= 19), or filgrastim plus plerixafor (n= 123) and was not available for three patients. The minimum acceptable CD34 target collection goal was 5 × 10 CD34+ cells per kilogram of actual body weight with extra days of collection defined as one or more additional days of leukapheresis for the sole purpose of obtaining ≥2 × 10 CD34 cells/kg for storage. No additional collection charges were tabulated for patients who were unable to store adequate progenitor cells (i.e., <2 × 10 PBSC/kg) or for patients who achieved their target goal in one pheresis session. The median age of the 169 patients was 61 years (36–77 years) and the median time from diagnosis to first autograft was 9 months (range 3–115) and was more than 2 years in 14 patients (8.2%). Overall, 100 patients (59%) received one treatment regimen, 46 (27%) received two regimens and 23 (14%) received three or more regimens prior to autograft and 95% of patients had a clinical response prior to undergoing ASCT1. Adequate PBSCs for storage was achieved in a single leukapheresis for 30.2% of patients who received plerixafor and filgrastim compared to less than 10% using chemotherapy plus filgrastim or filgrastim alone (χ= 21.9, p < 0.05, Table 1a). The range of PBPC mobilized was 2.25–82.32 × 10 CD34+ cells/kg (median 9.32 × 10) and 18 and 5 patients, respectively, failed to mobilize adequate stem cells or had insufficient information, leaving a total of 146 patients available for analysis. * Brenda W. Cooper [email protected]