Impact of the number of cryopreserved CD34+ cells in the infused blood grafts on hematologic recovery and survival in myeloma patients after autologous stem cell transplantation: Experience from the GOA study.

Abstract

Prospective data on the impact of CD34+ cell loss during cryopreservation and the amount of cryopreserved CD34+ cells infused after high-dose therapy on hematologic recovery and post-transplant outcome in multiple myeloma (MM) are scarce. This post-hoc study aimed to investigate factors associating with CD34+ cell loss during cryopreservation and the effects of the infusion of a very low number (<1.0 × 106 /kg, group A), low number (1-1.9 × 106 /kg, group B), and optimal number (≥2 × 106 /kg, group C) of thawed viable CD34+ cells on hematologic recovery, progression free survival, and overall survival after autologous stem cell transplantation among 127 patients with MM. In group C, pegfilgrastim use (P=0.001), plerixafor use (P=0.039), and older age ≥ 60 years (P=0.026) were associated with less loss of CD34+ cells during cryopreservation. Better mobilization efficacy correlated with greater CD34+ cell loss in group B (P=0.013 and P=0.001) and in group C (P < 0.001 and P < 0.001). Early platelet engraftment was slowest in group A (20 d vs 12 d in group B vs 11 d in group C, P=0.003). The infused viable CD34+ cell count <1.0 × 106 /kg seemed not to have influence on PFS (P=0.322) or OS (P=0.378) in MM patients. Cryopreservation impacts significantly on the CD34+ cell loss. A very low number of graft viable CD34+ cells did not affect PFS or OS.