Efficient peripheral blood stem cell mobilization with low-dose G-CSF (50 μ g/m²) after salvage chemotherapy for lymphoma

Abstract

We compared the use of low-dose G-CSF (50 μ g/m²/day), following salvage chemotherapy, for mobilization of PBSC with the results obtained in a comparable historical control group who received a standard dose of G-CSF (5 μ g/kg/day, approximately 200 μ g/m²/day). Thirty adult patients with relapsed or refractory lymphoma were treated with ifosfamide, VP-16, intermediate-dose Ara-C, methylprednisolone (IAPVP-16) and G-CSF 5 μ g/kg/day (group A, n = 15) or 50 μ g/m²/day (group B, n = 15) from day 6 until the end of leukaphereses. The duration of neutropenia and thrombocytopenia were equal in both groups. A median of two (1–3) leukaphereses were performed in both groups to harvest >3.5 × 10⁶/kg CD34⁺ cells. The numbers of circulating CD34⁺ cells on the first day of leukocyte recovery were similar in both groups in those patients mobilized after a first cycle of IAPVP-16. The numbers of circulating CD34⁺ cells were similar in patients mobilized after a first and after a second IAPVP-16 in group A. In the low-dose group (group B), however, the numbers of circulating CD34⁺ cells were significantly lower in those mobilized after a second than after a first course. Additionally, the product of the first leukapheresis contained significantly fewer CD34⁺ cells in those mobilized after a second course only in group B, with no differences in group A. Nevertheless, the final products harvested did not differ in the content of MNC, CFU-GM and CD34⁺ cells, suggesting that these differences are not clinically important. These results indicate that the use of low-dose G-CSF (50 μ g/m²/day) is as effective as 5 μ g/kg/day in accelerating neutrophil recovery and mobilizing CD34⁺ cells after a first cycle of IAPVP-16 salvage chemotherapy, resulting in a substantial decrease in costs, while more heavily pretreated patients may require higher doses of G-CSF for an equivalent mobilization.