Chemo-Mobilization Provides Superior Mobilization and Collection in Autologous Stem Cell Transplants but with Less Predictability and At a Higher Cost,

Chemotherapy + GCSF mobilization and GCSF alone are the most common mobilization regimens for autologous stem cell transplant (ASCT). We examined the benefits and limitations of both regimens in terms of mobilization success, predictability and costs.

A retrospective, multi-center chart review was conducted of multiple myeloma (MM) and lymphoma patients mobilized between January 1, 2006 and December 31, 2007 for ASCT. Patients were excluded if they were mobilized with plerixafor (Mozobil^®) or enrolled in a clinical trial of mobilization regimens. Data collected included demographics, disease and treatment history, mobilization regimen, blood counts, aphaeresis, remobilization, cells transplanted, time to engraftment and resource use. Stem cell collection practices and related clinical outcomes were analyzed separately for patients that were mobilized with chemotherapy + GCSF vs. GCSF alone. Resource use was evaluated using US unit cost data.

Data were collected for 227 consecutive patients from 11 centers (143 patients that received a chemotherapy + GCSF mobilization regimen and 84 patients who received GCSF alone). Total cells collected were significantly higher in the chemotherapy + GCSF mobilization group compared to GSF alone (18.6 × 10⁶/kg vs.7.0 × 10⁶/kg, p<0.001). While chemotherapy mobilization resulted in fewer days of aphaeresis (2.0 vs. 2.9; p<0.001), it was also associated with longer time to aphaeresis (12.5 days vs. 4.2 days; p<0.001), greater resource use and higher rates of febrile neutropenia. The chemotherapy + GCSF mobilization group had fewer re-mobilizations compared to GCSF alone (1.06 mobilizations vs. 1.2; p=0.016, 4.2% of chemotherapy + GCSF patients had more than one mobilization compared to 16.7% in GCSF alone).

Even with fewer aphaeresis days and re-mobilizations, the cost total cost of mobilization, remobilization and aphaeresis with chemotherapy + GCSF was higher than GCSF alone ($19,614 vs. 16,852; p=0.003). Higher chemotherapy + GCSF costs were driven by the costs of chemotherapy, and extra days of GCSF. Chemotherapy + GCSF was also harder to predict in terms of timing the first day of aphaeresis. In patients receiving GCSF alone, the majority (95%) of first day aphaeresis occurred between Monday and Wednesday with the remaining 5% occurring on a Thursday or Friday. In contrast, chemotherapy + GCSF mobilizations resulted in 74.1% of first day aphaeresis occurring between Monday and Wednesday, 12.6% on Thursday and Friday and a further 13.3% occurring on a Saturday or Sunday.

Significant differences in mobilization success, costs and predictability were observed between patients that received chemotherapy + GCSF and those that received GCSF alone. While a chemotherapy + GCSF mobilization regimen may provide better mobilization and collection, there is a trade-off in terms of predictability, time to collection, costs and rate of febrile neutropenia. However, as chemotherapy + GCSF may be used for the treatment of the underlying malignancy; its use may not be completely comparable to GCSF mobilization alone.

Grima:Cornerstone Research Group Inc.: Employment, Equity Ownership. Holmberg:Genzyme: Membership on an entity's Board of Directors or advisory committees, Research Funding; Millenium: Research Funding; Otsuka: Research Funding; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck: Research Funding; Celgene: Research Funding. Fung:Genzyme: Consultancy, Honoraria, Speakers Bureau. Brown:Cornerstone Research: Employment. Horwitz:Genzyme: Honoraria, Research Funding. Bernard:Cornerstone Research: Employment, Equity Ownership. Shaughnessy:Genzyme: Consultancy, Honoraria, Research Funding, Speakers Bureau; Millenium: Honoraria, Speakers Bureau; Otsuka: Honoraria, Speakers Bureau.