Peripheral blood progenitor cells mobilization in patients with Multiple Myeloma

Autologous stem cell transplantation (ASCT) is considered the standard therapy for younger patients with newly diagnosed symptomatic multiple myeloma (MM). The introduction into clinical practice of novel agents (i.e.: proteasome inhibitors and immunomodulatory derivatives [IMiDs]) has significantly contributed to major advances in MM therapy and prognosis. These novel agents are incorporated into induction regimens to enhance the depth of response before ASCT and further improve post-ASCT outcomes. Collection of adequate hematopoietic stem cells (HSCs) is necessary for successful autologous transplantation. The mobilizing regimen usually consists of cyclophosphamide or disease-specific agents, in combination with a hematopoietic cytokine, usually G-CSF, which mobilizes HPSCs into the bloodstream, in particular when administered after myelosuppressive chemotherapy. In some patients, the number of mobilized CD34+ cells is not sufficient to perform successful stem cell transplantation due to bone marrow damage by neoplastic proliferation and/or chemoradiotherapy. To improve the collection of CD34+ cells, the mobilization procedure can be repeated or an alternative chemotherapy regimen can be chosen. Recently, the new drug plerixafor (Mozobil®) has been introduced to increase the number of circulating CD34+ cells. Its use increases the level of functional HPCs in the peripheral blood, with long-term resettlement