Safety and Efficacy of Plerixafor when Administered in Outpatient Clinic or Self-Administered at Home

Introduction/Background/Significance: For patients with Non-Hodgkin lymphoma (NHL) and multiple myeloma (MM) who require an autologous stem cell transplant (ASCT), there are several strategies for the mobilization of hematopoietic stem cells (HSCs) from the bone marrow into the bloodstream. Granulocyte colony-stimulating factor (G-CSF) in combination with plerixafor or chemotherapy are commonly use methods for HSC mobilization. Due to rare reports of anaphylactic shock and serious hypersensitivity reactions, the prescribing information for plerixafor was updated in 2013 with recommendations to monitor patients for signs and symptoms of hypersensitivity during and for at least 30 minutes after administration. At The Mount Sinai Hospital (MSH), patients may receive plerixafor at the outpatient clinic or self-administer at home.

Materials and Methods/Case Presentation/Objective: To analyze the safety and efficacy of plerixafor when administered in the outpatient clinic or at home, a retrospective chart review was conducted of adult patients who underwent HSC collection with G-CSF plus plerixafor at MSH from July 1, 2022 to June 30, 2024. The co-primary outcomes focused on safety, including hypersensitivity reactions to plerixafor, hospitalizations or visits to the emergency department (ED) within 3 days of recent plerixafor administration, and early discontinuation of plerixafor due to an adverse event (AE). Secondary outcomes of interest were efficacy assessments of plerixafor, including peripheral blood CD34⁺/uL prior to each apheresis session, CD34⁺ cells collected in each apheresis session, number of apheresis days, and proportion of patients achieving collection targets of 5, 10, or 15 x 10^6/kg CD34⁺ cells.

Results/Description/Main Outcome Measures: Of the 325 patients screened, 257 were included in the study: 130 (86% with MM; 14% with NHL) received plerixafor in the outpatient clinic and 127 (100% with MM; none with NHL) self-administered plerixafor at home. Related to safety, two patients (1.5%) in the clinic administration group required an ED visit or hospitalization within 3 days of recent plerixafor administration due to catheter site bleeding and not attributed to plerixafor, while none were reported in the home administration group (p > 0.05). There were zero documented hypersensitivity reactions to plerixafor or early discontinuations of plerixafor due to AEs in either group. Related to efficacy, among the two groups of outpatient clinic versus home administration, median peripheral blood CD34⁺/uL prior to each apheresis session were similar on days 1 (64 vs. 59), 2 (30 vs. 35), and 3 (13 vs. 16). In both groups, median total CD34⁺ cells collected were approximately 12 x 10^6/kg and median number of apheresis days was 2. Optimal collection of ≥5 x 10^6/kg CD34⁺ cells was achieved in 112 (86.2%) vs. 114 (89.7%) patients (p > 0.05). Overall, 93 (71.5%) vs. 95 (74.8%) patients achieved the desired CD34⁺ collection target (p > 0.05).

Conclusions: There were no statistically significant differences among various safety and efficacy outcomes in patients who received plerixafor in the outpatient clinic or at home. These findings support the current practice of self-administration of plerixafor at home.