Similar 1 Year Survival of Patients Receiving Plerixafor (Mozobil*®) Plus G-CSF Versus Placebo Plus G-CSF Mobilized Autologous Grafts: Results From Two Phase 3 Randomized Trials in Patients with NHL or MM Undergoing Autologous Transplantation After Front-Line or Rescue Mobilization.
Authors: Micallef Ivana N , Stiff Patrick , Stadtmauer Edward , Bolwell Brian J. , Marulkar Sachin , Hsu Frank J , DiPersio John F. 
Published: October 2019

Abstract
Abstract 2319
Poster Board II-296

Background:
Data from two phase 3 clinical trials indicate that plerixafor plus G-CSF is safe and more effective than G-CSF alone in mobilizing CD34+ hematopoietic stem cells (HSC) for autologous HSC transplantation (auto-HSCT) in patients with non-Hodgkin's lymphoma (NHL) or multiple myeloma (MM). Herein we report 1-year overall survival in patients with NHL or MM who have undergone auto-HSCT with cells mobilized with plerixafor plus G-CSF compared to placebo plus G-CSF. Furthermore, we also report 1-year overall survival in patients with NHL who failed mobilization on either arm and entered a rescue protocol.

Methods:
Data were obtained from two prospective, randomized, double-blind, placebo-controlled, phase 3 clinical trials that compared the safety and efficacy of plerixafor (0.24 mg/kg/day SQ) plus G-CSF (10 mg/kg/day) with placebo plus G-CSF for mobilization of HSC for autologous HSCT in patients with NHL or MM. In the NHL study, patients in either study arm who failed mobilization (&0.8 ×106 CD34+ cells/kg in 2 days or &2 × 106 CD34+ cells/kg in 4 days) were eligible to enter the rescue protocol and received plerixafor + G-CSF mobilization. Overall survival in patients was estimated by the Kaplan-Meier method.

Results:
In the NHL study, 135/150 (90.0%) patients in the plerixafor group compared with 82/148 (55.4%) patients in the placebo group, underwent transplantation (p&0.001) with a median (range) of 5.41 (1.95-17.6) and 3.85 (1.98-8.74) × 106 CD34+ cells/kg, respectively (p&0.001). A total of 62 patients (10 from the plerixafor arm and 52 from the placebo arm) failed mobilization and proceeded to rescue mobilization with plerixafor + G-CSF. Of these, 52 patients (84%) proceeded to transplantation with a median (range) of 3.8 (1.1-10.5) x 106 CD34+ cells/kg. Kaplan-Meier estimates of 1-year overall survival for patients in the plerixafor and placebo groups in the primary ITT population (rescue patients were censored as of consent date for rescue) were 76.0% and 64.7%, respectively. Kaplan-Meier estimate of 1-year overall survival in the rescue group was 83.7%. The Log rank p-value comparing all 3 survival estimates (plerixafor, placebo and rescue) was 0.765 (Figure 1A). In the MM study, 142/148 (95.9%) patients in the plerixafor group and 136/154 (88.3%) patients in the placebo group underwent transplantation (p=0.014) with a median (range) of 5.40 (1.20-16.74) and 3.96 (1.76-16.88) × 106 CD34+ cells/kg, respectively (p&0.001). In this trial, Kaplan-Meier estimates of 1-year overall survival in the plerixafor and placebo groups were 93.6% and 95.8%, respectively (Log-rank p-value=0.771; Figure 1B).

Conclusions:
These data suggest that overall survival at 1 year is similar between patients with MM or NHL mobilized with plerixafor plus G-CSF compared to placebo plus G-CSF. Furthermore, in the NHL study, patient survival in the rescue protocol was similar to that seen in the phase III trial. Collection of follow-up data on overall survival is ongoing.

Disclosures:
Micallef: Genzyme Corporation: Membership on an entity's Board of Directors or advisory committees, Research Funding. Stiff:Genzyme Corporation: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Stadtmauer:Genzyme Corporation: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Bolwell:Genzyme Corporation: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Marulkar:Genzyme Corporation: Employment, Equity Ownership. Hsu:Genzyme Corporation: Employment, Equity Ownership. DiPersio:Genzyme: Honoraria.