Months Report from the Phase 3 Study of Plerixafor+G-CSF VS. Placebo+G-CSF for Mobilization of Hematopoietic Stem Cell for Autologous Transplant in Patients with NHL.

Introduction: We previously reported that plerixafor + G-CSF was as safe as and more effective than placebo + G-CSF in mobilizing hematopoietic stem cell for autologous transplant in patients with non-Hodgkins lymphoma (NHL) through 100 days follow-up (DiPersio ASH 2007). We report herein the 12 months data. Methods: This was a phase 3, multicenter, randomized, double-blind, placebo-controlled study. NHL patients requiring an autologous hematopoietic stem cell transplant were eligible. Patients received G-CSF (10 μg/kg) subcutaneously daily for up to 8 days. Beginning on evening of Day 4 and continuing daily for up to 4 days, patients received either plerixafor (240 μg/kg) or placebo subcutaneously. Starting on morning of Day 5, patients began daily apheresis for up to 4 days or until ≥ 5 x 106 CD34+cells/kg were collected. We report herein the 12 months graft durability and hematology data. Results: As reported previously, 89/150 (59%) patients in the plerixafor group and 29/148 (20%) patients in the placebo group met the primary endpoint of collecting ≥ 5 x 106 CD34+ cells/kg in ≤ 4 days of apheresis, p < 0.001. 135 patients (90%) in plerixafor group and 82 patients (55%) in placebo group underwent transplantation. Median time to neutrophil and platelet engraftment was similar in both groups. There were no differences in graft durability through 12 months follow-up between the two groups. Two plerixa for treated patients had graft failure (one had pre-existing MDS and one developed AML). One plerixafor-treated patient had delayed platelet engraftment. The hematology profiles were similar between the two groups through 12 months follow-up, except that patients in the plerixafor group had significantly higher platelet count at 12 months than patients in the placebo group (p=0.026) (Table 1). During the 12 months follow-up, 14/135 (10.4%) patients in plerixafor group and 10/82 (12.2%) patients in the placebo group died. 7/14 in the plerixafor group and 5/10 in the placebo group died of disease progression. Plerixafor + G-CSF Placebo + G-CSF Hematology data presented as mean ± SD and n= number of patients with available data aAll patients who underwent transplantation bAll patients who underwent transplantation and had laboratory data at the study visit cP values were NS for all variables at all time points between groups except for platelet count at 12 months (p=0.026) Graft durability (n, %) 100 daysa 128/135 (94.8%) 78/82 (95.1%) 6 monthsb 120/123 (97.6%) 77/78 (98.7%) 12 monthsb 110/112 (98.2%) 65/65 (100.0%) Platelet (x 109/L) 100 days 183 ± 83 (n= 113) 169 ± 81 (n=63) 6 months 190 ± 78 (n=100) 180 ± 77 (n=64) 12 monthsc 209 ± 81 (n=50) 170 ± 78 (n=37) Neutrophils (x 109/L) 100 days 3.1 ± 1.7 (n=107) 3.2 ± 2.1 (n=61) 6 months 3.3 ± 1.4 (n=98) 3.8 ± 2.6 (n=64) 12 months 3.5 ± 1.4 (n=50) 4.2 ± 2.7 (n=38) Hemogloblin (mg/dL) 100 days 12.3 ± 1.5 (n=112) 12.3 ± 1.5 (n=63) 6 months 12.5 ± 1.5 (n=100) 12.4 ± 1.5 (n=64) 12 months 13.0 ± 1.4 (n=50) 12.7 ± 1.6 (n=37) Conclusions: The addition of plerixafor to G-CSF resulted in higher CD34+ cell collection in fewer days of apheresis and higher proportion of patients proceeding to transplant than G-CSF alone. Importantly, this 12 months report showed that transplants with cells collected with plerixafor resulted in graft durability rates that were similar to cells collected with G-CSF alone.