A phase IV, randomized, multicenter, open-label trial comparing efficacy and systemic exposure for a standard weight-based dose versus a fixed dose of plerixafor in combination with G-CSF in patients with Non-Hodgkin's lymphoma weighing ≤70 kg.

A randomized, multicenter, open-label study explored the effect of a fixed-dose (FD) of plerixafor versus the approved weight-based (WB) dose for the mobilization of hematopoietic stem cells (HSCs) in patients with non-Hodgkin's lymphoma and a body weight of ≤70 kg. After mobilization with granulocyte colony-stimulating factor (G-CSF) 10 μg/kg/day for 4 days, patients were randomized 1:1 to either plerixafor FD 20 mg (n = 30) or WB 0.24 mg/kg (n = 31) on the evening of Day 4. Co-primary endpoints were the proportion of patients achieving ≥5 × 106 CD34+ cells/kg in ≤4 days of apheresis, and total systemic exposure to plerixafor (area under the concentration-time curve from 0 to 10 h [AUC0-10]). There was no statistically significant difference between the proportion of patients attaining the primary efficacy endpoint (60% FD arm, 55% WB arm; P = 0.395). Exposure to plerixafor was greater in the FD arm relative to the WB arm; however, there was no appreciable difference regarding fold increases of peripheral blood CD34+ cells. The safety profile was similar between treatment groups. These results suggest there is no statistically significant difference in HSC mobilization with a standard WB dosing regimen of plerixafor plus G-CSF in patients with low body weight compared with an FD regimen.