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 × 10 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 [AUC]). 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.