Effectiveness of Single-Dose Plerixafor in Enhancing Peripheral Blood Progenitor Cell Yield and Rate of Second Collection in Autologous Transplant

Introduction

Lymphoma and myeloma account for 5% of all new cancer diagnoses. Treatment for these conditions may include Autologous Stem Cell Transplantation (ASCT) in addition to chemoimmunotherapy, with the aim of enhancing outcomes.

Standard mobilization for these patients involves the use of G-CSF such as filgrastim 10 μg/kg/day for 5-7 days. Given the increased odds of poor mobilization in ASCT patients, which can lead to the need of multiple apheresis sessions or even the unfeasibility of ASCT, strategies to overcome this potential limitation are of great interest. As such, the use of plerixafor 0.24 mg/kg leads to higher CD34+ cell yields, as well as decreased risk of multiple apheresis sessions. Unfortunately, many patients in resource-limited nations often struggle to afford even a single dose of plerixafor, which stresses the need to characterize its effectiveness in settings bound to economic constraints.

Objectives

To evaluate the effect of single-dose plerixafor in cases of poor mobilization, defined as <20 CD34+ cells/μL on day 4 - 6 of mobilization.

Material and Methods

A retrospective, longitudinal, observational study was conducted from January 2016 to December 2023, based on the medical records of patients with Hodgkin Lymphoma, Non-Hodgkin Lymphoma and Multiple Myeloma, who were subject to ASCT in a university hospital in Monterrey, Mexico. Age, sex, diagnosis, CD34+ cell yield, G-CSF daily dose and duration, use of plerixafor, and collection were considered.

Results

A total of 201 patients undergoing 222 apheresis sessions after mobilization with filgrastim with or without plerixafor, were included. Male predominance was observed (n= 106, 52.7%), and median age was 54 years (range 7 - 77). More than half of the patients had Multiple Myeloma (n= 116, 57.7%), vs 34 cases with Hodgkin Lymphoma (16.9%) and 51 with Non-Hodgkin Lymphoma (25.4%).

Most patients underwent a single apheresis session (181, 81.5%), in contrast to 2 aphereses in 19 patients (17.1%) and only 1 patient with 3. The median CD34+/μL count of the cohort was 9 (IQR 4.2 - 13.3). CD34+/μL count prior to the first session was 9.2 (IQR 4.5 - 12.9) vs 3.9 (IQR 3.0 - 43.1) in a second or third session (p= 0.99). The median CD34+ cell yield was 4.8 x10⁶ (IQR 2.8 - 8.3) for the entire group, 5.2 x10⁶ (IQR 3.3 - 8.5) in those undergoing a single session, and 2.1 x10⁶ (1.5 - 3.4) in cases with ≥2 sessions (p <0.001); 93% of participants achieved a CD34+ cell yield of >2 x10⁶ cel/kg in a single or multiple aphereses.

Plerixafor was used in 138/222 aphereses (62.2%), which constituted 66.7% (134/201) of patients. A dose of 0.24 mg/kg was used in 73.9% (102/138) cases, vs 0.12 mg/kg in 36/138 (26.1%). The median dose was 0.24 mg/kg (IQR 0.12 - 0.24). Plerixafor was used in single-apheresis cases in 67.4% (122/181), in contrast to 60% (12/20) in cases with multiple-apheresis (p= 0.5). Plerixafor was used at least once during the mobilization of 124/187 (66.3%) patients who achieved a CD34+ harvest ≥2 x10⁶ cel/kg, in contrast to 10/14 (71.4%) patients with a cell yield <2 x10⁶ cel/kg (p= 0.77). The total CD34+ cell yield across single or multiple aphereses in patients who received plerixafor had a significantly higher median cell yield (5.4 x10⁶ cel/kg, IQR 3.4 - 8.5) than those that did not (4.2 x10⁶ cel/kg, IQR 2.4 - 6.9) (p= 0.02). Of the first-time apheresis sessions, those in which plerixafor was used required significantly less subsequent aphereses (9/131, 6.9%) than the group that did not use plerixafor (11/70, 15.7%) (p= 0.04).

Conclusion

Based on our results, single dose plerixafor seems to be effective in improving the CD34+ cell yield and reducing the need for subsequent apheresis sessions in patients with poor mobilization prior to ASCT.

Gomez-Almaguer:Blueprint Medicines: Research Funding; Seattle Genetics: Research Funding; Astex Pharmaceuticals: Research Funding; Gilead/Forty Seven: Research Funding; Incyte: Research Funding; Amgen: Consultancy, Other: Advisory board, Research Funding, Speakers Bureau; Janssen: Consultancy, Other: Advisory board, Speakers Bureau; Novartis: Consultancy, Other: Advisory board, Speakers Bureau; Takeda: Consultancy, Other: Advisory board, Research Funding, Speakers Bureau; BMS: Consultancy, Other: Advisory board, Speakers Bureau; Tevas: Speakers Bureau; Kartos Therapeutics: Research Funding; AbbVie: Research Funding, Speakers Bureau; Roche: Speakers Bureau; Sanofi: Speakers Bureau; ConstellationPharmaceuticals: Research Funding. Gomez-De Leon:Abbvie: Honoraria; Amgen: Honoraria; bms: Honoraria; Novartis: Honoraria; Pfizer: Honoraria; Janssen: Honoraria; Sanofi: Honoraria, Other: Advisory board; Janssen: Other: Advisory board.