Supplementary Material for: The induction regimen does not affect stem cell collection in adult patients with Ewing sarcoma

Background: Ewing Sarcoma (ES) is one of the most frequent sarcomas in children and young adults. Dose-intensified induction with vincristine, doxorubicin, cyclophosphamide, ifosfamide and etoposide (VDC/IE) proved to be more efficient than vincristine, ifosfamide, doxorubicin and etoposide (VIDE) and has emerged as a new standard. Here we analyzed peripheral blood (pB) and stem-cell yields of adult patients after the induction with VDC/IE and compared them with historic control after VIDE induction. Methods: Stem-cell collections of six adult ES patients (all male) after VDC/IE were analyzed. Stimulation with filgrastim 5µg/kg bid was applied in all patients. Results: All patients underwent stem-cell collection with a single apheresis without the use of plerixafor. Collections were performed after 2 (n=2), 3 (n=1), and 4 (n=3) courses of induction chemotherapy. Median CD34+ in peripheral blood [/µl] was 176.3 compared to 68.3 in the historic cohort (p=0.26). The median yields of CD34+, CD3+ and CD56+ [106 cells/kg body weight] in the actual and in the historic cohorts did not differ. No difference regarding the collection efficiency nor vitality 24 hours after thawing of the cryoconserved products were noticed. Conclusion: Intensification of induction does not seem to affect the feasibility of stem cell mobilization and the collection or graft composition in adult patients with ES. Confirmation of our findings in larger cohorts is warranted.