Plerixafor hydrochloride: A novel agent for the mobilization of peripheral blood stem cells

Plerixafor is a novel small molecule that inhibits CXCR4 binding to SDF-1, an interaction that is a principal regulator of hematopoietic stem cell trafficking. Phase I studies demonstrated that a single plerixafor hydrochloride dose results in a marked increase in white blood cell count and circulating CD34⁺ stem cells. Subsequent single-arm and randomized clinical trials have established the efficacy of plerixafor for autologous stem cell mobilization, both combined with granulocyte colony-stimulating factor (G-CSF) and as a single agent. In December 2008 the FDA approved plerixafor in combination with G-CSF for autologous stem cell mobilization in patients with non-Hodgkin lymphoma or multiple myeloma. Plerixafor is also effective for stem cell mobilization in patients with Hodgkin lymphoma and in those who have failed a prior cytokine or chemotherapy mobilization. Preliminary studies of plerixafor in sibling donors demonstrate its efficacy for allogeneic stem cell mobilization, without any observed increase in graft failure or graft versus host disease. This review will summarize clinical trials, current use for autologous stem cell mobilization and future directions for plerixafor.