Multiple myeloma patients treated with lenalidomide-based regimens frequently experience delayed peripheral blood...

Autologous stem cell transplantation remains a milestone procedure for transplant-eligible MM patients who achieve hematological remission; however, some agents can have unpredictable effects on PBSC collection, such as lenalidomide, a second generation IMiD, that can potentially have negative impacts on stem cell apheresis. Previously published studies have shown controversial results and using post-hoc analysis. In our real-life study, we confirmed the strong negative impact of lenalidomide on PBSC collection by comparing lenalidomide-treated patients with a control cohort of thalidomide-treated subject, also showing a more frequent use of plerixafor to mitigate these effects, thereby reducing the reliance on cyclophosphamide, that was associated with lower risk of prolonged apheresis sessions. Indeed, we showed that lenalidomide use significantly impaired stem cell collection, with prolonged apheresis sessions and lower CD34⁺ cell collection on day 1, while post-transplant outcomes did not significantly differ between groups. Our real-life bi-center experience is of great interest in the era of daratumumab-based regimens as first-line therapy for autologous stem cell transplantation-eligible MM patients, because the concomitant use with lenalidomide might negatively affect PBSC mobilization, urging for more tailored PBSC collection strategies.