Day-4 plerixafor on peripheral blood stem cell collection for autologous transplantation: A retrospective study

In autologous peripheral blood stem cell (PBSC) mobilization, granulocyte-colony stimulating factor (G-CSF) is typically administered for 5-8 days. Plerixafor is generally initiated on day five of mobilization, often requiring multiple apheresis sessions and repeated dosing. Strategies to optimize mobilization efficiency and minimize procedures remain an unmet need.

To evaluate whether administering plerixafor on day 4 instead of day 5 improves PBSC collection efficiency and reduces the number of apheresis sessions required for autologous stem cell transplantation (ASCT) candidates.

A retrospective study of fifty patients undergoing PBSC mobilization with G-CSF at the University of Louisville, Brown Cancer Center. Patients were divided into two groups: day-4 plerixafor versus standard day-5 plerixafor administration. The primary outcome was achieving the program's minimum cell on the planned collection day. Secondary outcomes include the proportion achieving target collection in the first session, the need for additional plerixafor doses, and healthcare costs.

Compared with day-5 administration, day-4 plerixafor was associated with a higher median CD34 + yield and a greater proportion achieving target collection in a single session (92% vs 16% in the day-5 group), and 88% completed PBSC collection in a single apheresis session in the day-4 group compared to 32%. There were fewer total apheresis days, and no significant differences were observed in engraftment times or adverse events.

Plerixafor on day 4 appears to enhance PBSC collection efficiency and reduce the need for multiple apheresis sessions compared with conventional day-5 administration. These findings support consideration of earlier plerixafor use in mobilization protocols, though larger studies are warranted to confirm clinical and cost-effectiveness.