Stem cell mobilization in patients with newly diagnosed multiple myeloma after lenalidomide induction therapy.

Lenalidomide has raised concerns regarding its potential impact on the ability to collect stem cells for autologous stem cell transplantation, especially after prolonged exposure. The use of cyclophosphamide plus granulocyte colony-stimulating factor (G-CSF) to mobilize peripheral blood stem cells may overcome this concern. In newly diagnosed multiple myeloma (MM) patients, we investigated the influence of lenalidomide on stem cell collection. In a prospective study, 346 patients received four cycles of lenalidomide-dexamethasone (Rd). Stem cells were mobilized with cyclophosphamide and G-CSF. Patients failing to collect a minimum of 4 × 10(6) CD34(+)/kg cells received a second mobilization course. After mobilization, a median yield of 8.7 × 10(6) CD34(+)/kg was obtained from patients receiving Rd induction. After first mobilization, inadequate yield was observed in 21% of patients, whereas only 9% of patients failed to collect the target yield after the second mobilization attempt. In conclusion, we confirm that a short induction with lenalidomide allowed sufficient stem cells collection to perform autologous transplantation in 91% of newly diagnosed patients.