High-dose versus low-dose cyclophosphamide in combination with G-CSF for peripheral blood progenitor cell mobilization.

Background: To compare the mobilizing effects and toxicities of two different doses of cyclophosphamide (CY) plus lenograstim (glycosylated G-CSF), we performed a prospective randomized study by enrolling patients suffering with either high-risk Non-Hodgkin's lymphoma (NHL) or breast cancer undergoing ablative chemotherapy.

Methods: The NHL patients received 4 cycles of CHOP and the breast cancer patients received 2-3 cycles of FAC (FEC) adjuvant chemotherapy. Then, the patients were randomly allocated to receive CY 4 g/m2 (arm A) or 1.5 g/m2 (arm B) in combination with lenograstim. Large volume leukapheresis was carried out and it was continued daily until the target cell dose of 2 x 10(6) CD34+ cell/kg was reached.

Results: Twenty-seven patients were enrolled in the study. The median number of leukaphereis sessions actually performed was 2.5 sessions in arm A and 3 sessions in arm B. The target cell dose was obtained with the median number of one leukapheresis session in both arms of the study (p=0.09). The collected number of CD34+ cells in the leukapheresis products was higher in arm A than arm B (22.4 vs. 9.9 x 10(6)/kg, respectively, p=0.05). Grade III or IV leukopenia was present in 14/15 patients (94%) in arm A and in 1/12 patients (8%) in arm B (p<0.0001). Grade Ill or IV thrombocytopenia was present in 8/15 patients (54%) in arm A, but this was not present in any patients of arm B (p=0.0004). Neutropenic fever occurred in 6/15 patients (40%) in arm A, and in 1/12 patients (8%) in arm B (p=0.09). The hematological recovery of the leukocytes and platelets after transplantation was not statistically different between the two doses.

Conclusion: Low-dose CY plus lenograstim is a safe and effective mobilizing regimen.