A combination of low-dose cyclophosphamide and colony-stimulating factors is more cost-effective than granulocyte-colony-stimulating factors alone in mobilizing peripheral blood stem and progenitor cells

BACKGROUND: The use of peripheral blood progenitor cells (PBPCS) instead of autologous bone marrow leads to more rapid engraftment following high- dose chemotherapy. Mobilization regimens differ with respect to toxicity, efficiency, and cost. STUDY DESIGN AND METHODS: Two cohorts of patients with breast cancer received one of two mobilization regimens: granulocyte-colony- stimulating factor (G-CSF) at 10 pg per kg was given subcutaneously for 5 days, with leukapheresis begun on day 6, or low-dose cyclophosphamide followed by sequential granulocyte-macrophage-CSF (GM-CSF) at 5 pg per kg for 5 days and by G-CSF at 10 μg per kg, with leukapheresis begun on Day 11. Results of CD34+ cell collection, engraftment, and costs of mobilization were determined. RESULTS: The combination chemotherapy and growth factor regimen was more efficient in mobilizing CD34+ cells. Sixty-six percent of patients reached a target 4 x 10⁶ CD34+ cells per kg in a single leukapheresis session with the combination regimen, compared to 14 percent who received G- CSF alone (p<0.01). The mean number of leukapheresis sessions required to reach a target of 4 x 10⁶ CD34+ cells per kg was 1.3 for the combination regimen and 2.7 for the regimen of G-CSF alone (p<0.01). One patient in the chemotherapy and growth factor group developed febrile neutropenia. Engraftment was similar in both cohorts of patients. The cost of mobilization, including all supplies and cryopreservation, was $7381 for the G-CSF regimen and $5508 for the chemotherapy regimen (p<0.05). This reduction was attributed to the lower number of leukapheresis and cryopreservation sessions, which outweighed the slight increase in expense for chemotherapy and growth factor in the combination regimen. CONCLUSION: This combination mobilization regimen allowed the predictable and efficient collection of CD34+ cells from the peripheral blood in a limited number of leukapheresis sessions, which reduced the cost of mobilization by approximately 25 percent.