Long-term follow up of patients proceeding to transplant using plerixafor mobilized stem cells and incidence of secondary myelodysplastic syndrome/AML
We report the long-term follow up of 49 patients (pts) enrolled on plerixafor compassionate use protocol. Thirty-seven pts (76%) had failed one previous mobilization attempt, while 12 (24%) had failed two or more previous attempts. Using the combination of plerixafor and granulocyte colony-stimulating factor, we collected⩾2.5 × 106 CD34+cells/kg in 33 pts (67%). Forty-three of the 49 pts proceeded to an auto-SCT (ASCT). The median days to WBC and platelet engraftment were 11 (range, 9–13 days) and 16 (range, 11–77 days) days post ASCT, respectively. The median WBC count, Hb and platelet counts 1 year after ASCT were 4.7 × 109/L, 12.2 g/dL and 109 × 109/L, respectively. With median follow up of 42 months (range <1–54 months), 21 pts had evidence of disease progression. Five pts developed myelodysplastic syndrome (MDS)/AML at median of 29 months post ASCT. The cumulative incidence of MDS/AML at 42 months was 17% (95% confidence interval, 6 to 32%). Development of secondary MDS/AML in pts proceeding to ASCT after plerixafor mobilization needs to be studied further in a larger cohort.