Utilization and Cost Implications of Hematopoietic Progenitor Cells Stored for a Future Salvage Autologous Transplantation or Stem Cell Boost in Myeloma Patients

Abstract

Autologous hematopoietic cell transplantation (autoHCT) is a standard initial treatment for multiple myeloma (MM). Consensus guidelines recommend collecting sufficient hematopoietic progenitor cells (HPCs) for 2 autoHCTs in all eligible patients. Despite a lack of published data on the utilization of HPCs stored for future use, it is common practice across transplantation programs to collect enough HPCs for 2 autoHCTs in MM patients. In this single-center retrospective study, we analyzed the utilization of HPCs collected and stored at the time of first autoHCT in patients with MM, along with the cost implications of HPC collection targets sufficient for 2 transplantations. In a cohort of 400 patients (median age, 63 years; range, 22 to 79 years), after a median follow-up of 50.4 months, 197 patients had relapsed and 36 had received HPC infusion as salvage autoHCT (n = 29) and/or HPC boost (n = 8). In this cohort, a median CD34⁺ cell dose of 4.3 × 10⁶/kg (range, 1.1 to 12.94.3 × 10⁶/kg) was used for first autoHCT, and a median of 4.4 × 10⁶/kg (range, 1.0 to 20.2× 10⁶/kg) CD34⁺ cells were stored for future use. At 6 years after the first autoHCT, the estimated cumulative incidence of salvage autoHCT was 12.0% without HPC boost and 13.9% with HPC boost. HPC utilization was significantly higher in the 60- to 64-year age group, whereas no patients who were age ≥70 years at the time of first autoHCT received salvage autoHCT. Using the CD34⁺ cell dose infused during the first autoHCT as the cutoff for individual patients, the estimated mean additional cost of HPC collection intended for subsequent use (over and above the HPCs used for first autoHCT) was $10,795 ($4.32 million for the entire cohort), an estimated 14% of which (ie, $583,600) was actually used up in salvage autoHCT by 6 years from first autoHCT. In conclusion, our results suggest the need for reappraisal of HPC collection targets for salvage autoHCT and argue against HPC collection and storage for salvage autoHCT in patients age ≥70 years at the time of first autoHCT.

Keywords: Cryopreservation; Hematopoietic progenitor cell boost; Hematopoietic progenitor cells; Mobilization; Multiple myeloma; Salvage hematopoietic cell transplantation.