Purpose: To evaluate (1) the effect of granulocyte colony-stimulating factor (G-CSF) on peripheral-blood stem-cell (PBSC) mobilization; (2) the rate of hematopoietic recovery after G-CSF-mobilized PBSC transplantation; and (3) the outcome of high-dose myeloablative therapy and PBSC transplantation in patients with relapsed or refractory lymphoma.
Patients and methods: Ninety-five patients with lymphoma underwent high-dose therapy followed by PBSC transplant in three sequentially treated cohorts of patients in a nonrandomized study. The first 30 patients received nonmobilized PBSCs (unprimed) without G-CSF after transplant, the next 26 patients received PBSC that were mobilized with G-CSF 5 micrograms/kg/d (primed-5) plus G-CSF after transplant, and the last 39 patients received PBSC mobilized by G-CSF 10 micrograms/kg/d (primed-10) plus G-CSF after transplant. The conditioning regimen consisted of fractionated total-body irradiation (FTBI) 12 Gy in combination with etoposide 60 mg/kg and cyclophosphamide 100 mg/kg. Patients with prior radiotherapy received carmustine (BCNU) 450 mg/m2 instead of FTBI.
Results: The use of G-CSF-mobilized PBSCs in combination with G-CSF posttransplant resulted in a significantly accelerated time to recovery of both granulocyte and platelet when compared with the unprimed group. The median number of days to an absolute granulocyte count (ANC) of greater than 0.5 x 10(9)/L was 10 days for G-CSF primed versus 20 days for the unprimed (P = .0001). The median days to platelet transfusion independence was 16 and 31 days (P = .0001) for the G-CSF primed and unprimed, respectively. There were also significant reductions in the number of platelet (P = .02) and RBC transfusions (P = .006) for the G-CSF primed. Multivariate analysis of prognostic factors identified CD34+ cell dose as the only additional factor predicting engraftment. Sixty-nine patients are alive at a median follow-up of 15.9 months (range, 7.4 to 63.7). The cumulative probability of 2-year disease-free survival is 59% (95% confidence interval [CI], 36% to 79%) and 39% (95% CI 25% to 55%) for patients with Hodgkin's disease and non-Hodgkin's lymphoma, respectively.
Conclusion: The use of G-CSF-mobilized PBSC after high-dose myeloablative therapy resulted in a rapid, complete, and sustained hematopoietic recovery. Disease-free survival over 2 years can be achieved in some patients with relapsed lymphoma after high-dose therapy and PBSC transplantation. However, longer follow-up is required to confirm the curability of this approach.