Flat-dose granulocyte colony-stimulating factor evaluation after autologous hematopoietic stem cell transplant in multiple myeloma patients: Does one dose fit all?

Introduction The current recommended granulocyte-colony stimulating factor (G-CSF) dose after autologous hematopoietic stem cell transplant (autoHSCT) in multiple myeloma patients is 5 mcg/kg/day administered subcutaneously until engraftment. Recently, our institution changed practice from weight-based to flat-dose G-CSF. The purpose of this study was to assess the impact of flat-dose G-CSF on time to engraftment among multiple myeloma patients of different weight groups. Methods Retrospective chart review was completed for adult patients with multiple myeloma who underwent autoHSCT from March 2018 through August 2019. Data collected included time to neutrophil engraftment, total length of hospitalization, length of stay post-transplant, time to platelet engraftment, use of intravenous fluconazole or acyclovir, parenteral nutrition use, incidence of febrile neutropenia, antibiotic use, and death. Differences in outcomes were compared between patients ≤80 kg versus those >80 kg. A secondary analysis was completed for patients ≤100 kg versus those >100 kg. Results There was no difference in time to neutrophil engraftment between weight groups (≤80 kg versus >80 kg: median = 12 days, p = 0.22; ≤100 kg versus >100 kg: median = 12 days, p = 0.52). There was a significant difference in intravenous fluconazole and acyclovir use between groups, with more use in the lower weight groups (≤80 kg versus >80 kg: 12 patients versus 10 patients p = 0.02; ≤100 kg versus >100 kg: 19 patients versus 3 patients p = 0.04). No significant differences were found for any other outcomes. Conclusion Utilizing a flat-dose of G-CSF for patients after autoHSCT does not appear to negatively affect patient outcomes. Institutions may benefit from using the 300 mcg dose of G-CSF for multiple myeloma patients after autoHSCT.