Alexander Biederstädt

Background Despite recent advances in the treatment of multiple myeloma, high‐dose chemotherapy followed by autologous hematopoietic stem cell transplantation (ASCT) remains an essential therapeutic keystone. As for the stem cell mobilization procedure, different regimens have been established, usually consisting of a cycle of chemotherapy followed by application of granulocyte‐colony stimulating factor (G‐CSF), although febrile neutropenia is a common complication. Following national guidelines, our institution decided to primarily use G‐CSF only mobilization during the COVID‐19 pandemic to minimize the patients' risk of infection and to reduce the burden on the health system. Study Design and Methods In this retrospective single‐center analysis, the efficacy and safety of G‐CSF only mobilization was evaluated and compared to a historic control cohort undergoing chemotherapy‐based mobilization by cyclophosphamide and etoposide (CE) plus G‐CSF. Results Although G‐CSF only was associated with a higher need for plerixafor administration ( p < .0001) and a higher number of apheresis sessions per patient ( p = .0002), we were able to collect the target dose of hematopoietic stem cells in the majority of our patients. CE mobilization achieved higher hematopoietic stem cell yields ( p = .0015) and shorter apheresis sessions ( p < .0001) yet was accompanied by an increased risk of febrile neutropenia ( p < .0001). There was no difference in engraftment after ASCT. Discussion G‐CSF only mobilization is a useful option in selected patients with comorbidities and an increased risk of serious infections, especially in the wintertime or in future pandemics.