Rapid Mobilization of CD34+ Cells Following Administration of the CXCR4 Antagonist AMD3100 to Patients with Multiple Myeloma and Non-Hodgkin's Lymphoma

Purpose: Interactions between the chemokine receptor CXCR4 and its ligand stromal derived factor-1 regulate hematopoietic stem-cell trafficking. AMD3100 is a CXCR4 antagonist that induces rapid mobilization of CD34+ cells in healthy volunteers. We performed a phase I study assessing the safety and clinical effects of AMD3100 in patients with multiple myeloma (MM) and non-Hodgkin's lymphoma (NHL).

Patients And Methods: Thirteen patients (MM, n=7; NHL, n=6) received AMD3100 at a dose of either 160 microg/kg (n=6) or 240 microg/kg (n=7). WBC and peripheral blood (PB) CD34+ cell counts were analyzed at 4 and 6 hours following injection.

Results: AMD3100 caused a rapid and statistically significant increase in the total WBC and PB CD34+ counts at both 4 and 6 hours following a single injection. The absolute CD34+ cell count increased from a baseline of 2.6 +/- 0.7/microL (mean +/- SE) to 15.6 +/- 3.9/microL and 16.2 +/- 4.3/microL at 4 hours (P=.002) and 6 hours after injection (P =.003), respectively. The absolute CD34+ cell counts observed at 4 and 6 hours following AMD3100 were higher in the 240 microg/kg group (19.3 +/- 6.9/microL and 20.4 +/- 7.6/microL, respectively) compared with the 160 microg/kg group (11.3 +/- 2.7/microL and 11.3 +/- 2.5/microL, respectively). The drug was well tolerated and only grade 1 toxicities were encountered.

Conclusion: AMD3100 appears to be a safe and effective agent for the rapid mobilization of CD34+ cells in patients who have received prior chemotherapy. Further studies in combination with granulocyte colony-stimulating factor in patients with lymphoid malignancies are warranted.