Plerixafor (Mozobil®) Alone to Mobilize Hematopoietic Stem Cells from Multiple Myeloma Patients for Autologous Transplantation

Rapid and durable recovery of hematopoietic function after hematopoietic stem cell transplantation (HSCT) requires the infusion of a sufficient number of hematopoietic stem cells (HSC). Granulocyte colony-stimulating factor (G-CSF), either alone or with chemotherapy, has been the traditional backbone of regimens used to mobilize HSC. Plerixafor (previously known as AMD3100), a selective antagonist of CXCR4, has recently been approved for autologous HSC mobilization in combination with G-CSF. The current study assessed the safety and efficacy of plerixafor as a single agent when given subcutaneously and followed by apheresis 6 hours later for the mobilization of HSC for transplantation in 9 patients with multiple myeloma (MM). All patients mobilized enough cells for at least 1 transplant, and demonstrated prompt recovery of hematopoietic function. Median time to engraftment was 10.5 days for neutrophils and 21 days for platelets. Significant adverse events were not observed. Recovery of peripheral blood cell counts was durable in all surviving patients. Despite these successes, mobilization with plerixafor alone was modest. However, in clinical circumstances where G-CSF or chemotherapy based-mobilization should not be used, mobilization with plerixafor alone may be required and effective. Further research into single agent use should focus on alternate route of administration as well as adjustment of the timing of the apheresis to improve cell HSC yield (ClinicalTrials.gov registration number: NCT00396383)