Steady-state versus chemotherapy-based hematopoietic cell mobilization after anti-CD38-based induction therapy in newly diagnosed multiple myeloma.

BACKGROUND: The incorporation of anti-CD38 monoclonal antibodies (mAb) in induction regimens of newly diagnosed transplant-eligible multiple myeloma (MM) patients has been established as a new standard. However, the optimal strategy of stem cell mobilization in this context is not yet clear. STUDY DESIGN AND METHODS: From May 2020 till September 2022, we retrospectively reviewed patients receiving anti-CD38 mAb-based induction therapy followed by stem cell mobilization either in a steady-state protocol (SSM) using 10 µg/kg granulocyte colony-stimulating factor (G-CSF) for 5 days or in a chemotherapy-based protocol (CM) using 1-4 g/m2 cyclophosphamide and G-CSF. RESULTS: Overall, 85 patients (median age 61 years) were included in the analysis. In total, 90 mobilization attempts were performed, 42 with SSM and 48 with CM. There was no significant difference in the median concentration of CD34+ cells in peripheral blood (PB) prior to apheresis between SSM and CM (61/µL vs. 55.4/µL; p = .60). Cumulative CD34+ yields did not differ between the groups with median of 6.68 and 6.75 × 106 /kg body weight, respectively (p = .35). The target yield (≥4 × 106 CD34+ cells/kg body weight) was reached in 88% (CM) and 86% (SSM), with a high proportion even after a single apheresis session (76% vs. 75%). Plerixafor was found to be more frequently used in SSM (52%) than in CM (23%; p < .01). A total of 83 patients underwent autologous transplantation and all were engrafted. CONCLUSIONS: Stem cell collection in patients undergoing anti-CD38-based induction therapy is feasible with either CM or SSM, although SSM more frequently requires plerixafor.

Analysis of stem cell collections in adult patients with Ewing sarcoma.

BACKGROUND: Ewing sarcoma is one of the most frequent soft-tissue tumors in pediatric patients. The current treatment protocols recommend stem cell apheresis (SCA) after completion of the second course of induction therapy with vincristine, ifosfamide, doxorubicine, and etoposide (VIDE). The feasibility of SCA and graft compositions in adult patients with Ewing sarcoma have not been previously analyzed. METHODS AND MATERIALS: The authors analyzed 29 stem cell collections of 19 adult patients (9 male, 10 female) at a median age of 27 (range 19-53) years mobilized after VIDE (n = 17), cyclophosphamide/topotecan (n = 1) or vincristine, dactinomycin and ifosfamide (n = 1) chemotherapy. All patients were mobilized with filgrastim 5 µg/kg twice daily from day +7 of chemotherapy. The collections were performed if CD34+ cell count in peripheral blood was >10/µL. The target yields were ≥4×106 CD34+ cells/kg body weight. RESULTS: Median CD34+ cells/µL in peripheral blood before SCA were 45.8 (range 6.7-614.4)/µL. The median cumulative yields were 10.6 (range 1.5-38.8) CD34+ cells/kg body weight and ≥2×106 in all but two patients (89%). CD34, CD3, and CD56 yields in collections after the third VIDE and after later courses did not differ. Four patients underwent high-dose therapy with autologous transplantation, and all were engrafted. DISCUSSION: Stem cell mobilization is feasible in most Ewing sarcoma patients. Additionally, the present study's data suggest that it is safe to postpone stem cell collection to a later VIDE chemotherapy cycle if medically indicated.