Ancestim (r-MetHuSCF) is available in France for compassionate use in patients who are candidates for high-dose chemotherapy and autologous transplantation, and who failed in previous attempts at mobilization and collection. We report here data from 513 adult patients who benefited from this program, between January 1998 and July 2007. Given with systematic premedication, ancestim was generally well tolerated, although severe but not life-threatening adverse events were reported in 12 individuals. Overall, a graft was obtained or completed for 235 patients (46%). The median number of collected CD34 þ cells was 3.00 Â 10 6 /kg (range: 0.03-39.50). The target threshold of 2 Â 10 6 CD34 þ cells/kg was reached in 161 patients (31%). Factors associated with collection were diagnosis of myeloma, no previous autologous transplant, no more than one previous failed attempt and a mobilization regimen including cytotoxic agents. A total of 207 patients (40%) proceeded to high-dose chemotherapy and autologous transplantation. The median time to reach 0.5 Â 10 9 /L neutrophils and 20 Â 10 9 /L platelets was 12 (6-40) and 13 (0-31) days, respectively. We conclude that a combination of ancestim with filgrastim successfully mobilized CD34 þ cells in peripheral blood, and allowed adequate collection in preparation for autologous transplantation in approximately one-third of poorly mobilizing patients.