Introduction: Lenalidomide (LEN) is a relatively new and very effective therapy for multiple myeloma (MM). Prior LEN therapy is associated with an increased risk of peripheral blood stem cell collection (PBSC) failure, particularly with filgrastim (G-CSF) alone. We performed a retrospective chart review of 319 consecutive MM patients who underwent apheresis to collect PBSCs for the first autologous stem cell transplant (ASCT).
Results: The median number of PBSCs collected in the LEN (+) group was significantly less than the LEN (-) group (6.34 vs. 7.52 × 10(6) CD34(+) cells/kg; p = 0.0004). In addition, the median number of apheresis sessions required for adequate PBSCs collection were significantly more in the LEN (+) group as compared to LEN (-) group (2 vs. 1 sessions; p = 0.002). In the LEN (+) group, there was a negative correlation between PBSCs collected and prior number of cycles of LEN (p = 0.0001). Rate of PBSC collection failure was 9% in the LEN (+) group and 5% in the LEN (-) group (p = 0.16). Only six patients who failed PBSC collection with G-CSF were able to collect adequate PBSCs with G-CSF + plerixafor. LEN exposure had no effect on neutrophil or platelet recovery post-ASCT.
Conclusions: Up to four cycles of LEN exposure have minimal negative impact on PBSC collection. Despite prolong exposure of LEN, PBSC collection was adequate for two ASCTs in the majority of patients and post-ASCT engraftment was not longer than expected; however, clinical relevance (complication rate, quality of life, cost) of prolonged LEN exposure on both PBSC and ASCT, should be evaluated in prospective clinical trials.