MM-400: Plerixafor and Granulocyte Colony-Stimulating Factor for Poor Mobilizers in Patients Undergoing Autologous Peripheral Hematopoietic Stem Cell Transplant: Single-Institution Study

Abstract

Context Autologous hematopoietic stem cell transplant (ASCT) has become the mainstay treatment for many hematological malignancies and solid tumors. An adequate number of stem cells must be collected for better ASCT outcomes, which is challenging in 5%–30% of patients. To improve mobilization, plerixafor is used, along with granulocyte colony-stimulating factor. Objective To evaluate the real-life efficacy of plerixafor and to identify factors associated with poor mobilization. Design and Setting This is a retrospective, single-center study involving patients who received plerixafor pre-ASCT between January 2013 and December 2020 at a tertiary care center in Lebanon. Patients We identified a total of 72 consecutive adult patients. Patients who received plerixafor were divided into two groups: poor mobilizers with pre-emptive use before first apheresis for those with peripheral CD34+ stem cells (PSC) 20 cells/µL. Main Outcome Measures The main endpoints were to evaluate characteristics of poor mobilizers, stem cell yields pre- and post-plerixafor, as well as the time to neutrophil and platelet engraftment. Results The median age at diagnosis was 54 years (12–73). 60% were males. 50 (70%) patients had multiple myeloma (MM), 12 (15%) had non-Hodgkin lymphoma, 7 (10%) had Hodgkin lymphoma, and 3 (4%) had solid tumors and Waldenstrom macroglobulinemia. The median follow-up was 9 months (1–59). 59 (82%) patients had low PSCs, requiring pre-emptive plerixafor prior to apheresis. 62% of MM and 54.5% of non-MM patients needed >1 collection. 97% of all patients collected CD34+ >2×106cells/kg post-plerixafor. The median collected final CD34+ cells post-plerixafor was 4.4×106/kg (1.84–18.62). Factors associated with poor mobilization were male gender, age at diagnosis >55 years, MM, and bone marrow involvement (p=0.041, p=0.031, p=0.04, and p=0.012, respectively). Median times to absolute neutrophil count (ANC) and platelet engraftment were 11 (4–26) and 17 (4–28) days, respectively. A longer ANC engraftment (>2 weeks) was observed in patients who were infused Conclusion These results can guide us to use plerixafor early in selected patients who are predicted to fail mobilization.