Utilization of stored autologous PBSCs to support second autologous transplantation in multiple myeloma patients in the era of novel agent therapy.

Outcomes in multiple myeloma (MM) have improved significantly with novel agent therapy and autologous stem cell transplantation (ASCT). ASCTs are typically planned as either tandem or a single transplant with additional stored PBSCs available for a second salvage transplant. To accommodate these strategies, many centers routinely collect and store adequate PBSCs for two ASCTs. We analyzed the cost associated with this practice by determining the expenses of PBSC collection, cryopreservation and storage, and the ultimate use of additional cryopreserved PBSCs in patients who had undergone at least one ASCT. There were 889 MM patients transplanted between 1993 and 2011 at our center. Most (N=726) had residual PBSCs in storage after their first ASCT (ASCT1). Only 135 patients underwent a second ASCT within a median of 14 months after ASCT1. The percentage of patients receiving a second ASCT declined over time. The resources required to collect and store unused PBSCs added up to 336 extra patient days of apheresis and 41 587 extra patient months of cryopreservation, translating into an average extra cost per patient of US$4981.12. A reconsideration of conventional PBSC collection and storage practices would save significant cost for the majority of MM patients who never undergo a second ASCT.

Should we purge?

Relapse due to either residual host disease or reinfused tumor cells remains the principal cause of treatment failure after autologous stem cell transplantation. Although it is intuitively attractive to remove putative tumor cells from autologous grafts prior to transplant and more than 1000 articles have been written on the subject, there are only limited data suggesting that purging autografts has any favorable effect on relapses or disease-free survival. Certain purging techniques that remove substantial numbers of T cells or destroy progenitor cells may have adverse effects such as delayed hematopoietic or T cell reconstitution. There is a critical need for large, well-designed trials that specifically address the value of a particular purging technique on relapses and disease-free survival after autologous stem cell transplant.