Impact of lenalidomide-based induction therapy on the mobilization of CD34 + cells, blood graft cellular composition, and post-transplant recovery in myeloma patients: a prospective multicenter study.

BACKGROUND: Lenalidomide is an immunomodulatory drug that is also currently used in transplant-eligible patients with multiple myeloma. Previous studies have suggested a negative impact of lenalidomide on the mobilization of CD34+ cells. No data are available regarding the more detailed composition of blood grafts after lenalidomide.

STUDY DESIGN AND METHODS: In a multicenter, prospective study, we analyzed the mobilization of CD34+ cells, graft cellular composition, and post-transplant hematologic recovery in 26 patients with multiple myeloma after lenalidomide-based induction and in 34 lenalidomide-naive controls with multiple myeloma. All patients were mobilized with low-dose cyclophosphamide plus granulocyte-colony-stimulating factor. The cellular composition of the grafts was analyzed from thawed, cryopreserved samples with flow cytometry. Graft function was evaluated by engraftment data and by complete blood counts until 12 months after the graft infusion.

RESULTS: Patients in the lenalidomide arm had lower median peak CD34+ counts and approximately 40% lower CD34+ cell yields from the first apheresis session, but these differences were not significant. The median total number of CD34+ cells collected was comparable (6.4 vs. 7.5 × 106 /kg). The number of apheresis sessions was higher in the lenalidomide group (2 vs. 1; p = 0.039). The blood graft composition was comparable between the groups. Hematologic recovery within 12 months post-transplant did not differ between the groups.

CONCLUSION: Lenalidomide-based induction seems to have an impact on the number of aphereses performed, but not on the total yields of the CD34+ cells in the graft. Neither cellular composition of the grafts nor post-transplant recovery was affected by the limited pre-transplant exposure to lenalidomide.