Pb2446: allogeneic stem cell transplantation with granulocyte colony-stimulating factor (g-csf) primed bone marrow: prospective study of the national bone marrow transplant center in tunisia

Topic: 22. Stem cell transplantation - Clinical Background: Granulocyte colony-stimulating factor (G-CSF) has been successfully used to accelerate hematological reconstitution after allogeneic stem cell transplantation (ASCT) and stem cell mobilization. Limited data are available on its efficacy and safety in patients receiving ASCT from G-CSF primed bone marrow transplants (P-BMT). Aims: We prospectively evaluated the outcomes of patients receiving myeloablative conditioning regimen and allogeneic P-BMT from matched sibling donors. Methods: A prospective transversal study was conducted to evaluate the efficacy and safety of P-BMT in patients transplanted between November 2021 and December 2022. Donors received a median dose of 10 ug/kg/day of subcutaneous G-CSF for 5 consecutive days. BM was harvested on day 5. the primary endpoints were hematological reconstitution and incidence of acute graft-versus-host disease (GVHD). Secondary endpoints were hospitalization duration, infections, antibiotic and anti-fungal duration. Results: A total of 28 consecutive patients were included. Median age was 33.5 years (range, 13-51 years). Underlying diseases were: acute leukemia (n=17), aplastic anemia (n=6), chronic myeloid leukemia (n=3), non-Hodgkin’s lymphoma (n=1) and myelofibrosis (n=1). The median age of donors was 34 years (range, 17-56 years). No significant adverse events were observed in donors. Conditioning regimen was chemotherapy-based in 24 (86%) patients and Total Body Irradiation in 4 (14%) patients. Median number of mononuclear cells and CD34+ cells infused were 2.8* 108/kg (range, 1.5-5.8 * 108/kg) and 1.62*106 (range, 0.66-4.08) respectively. Neutrophil and platelet recovery were observed at a median of 14 days (range, 11-25 days) and 18 days (range, 9-36 days) after transplantion, respectively. Acute GVHD ≥ grade II was observed in 17 (60%) patients (gastro-intestinal, n=14 and cutaneous, n=8). Sixteen patients responded to steroid and 1 patient required ruxolitinib. The median time of hospitalisation was 39 days (range, 29-104). The median number of blood cell and platlets units were 5 (range, 0-21) and 9 (range, 3-50), respectively. All patients developed fever post-transplant: 14 (50%) were of unknown origin, 4 (14%) were clinically documented and 10 (36%) were microbiologically documented (9 bacteremia, and 2 fungemia). Sixteen (57%) developed cytomegalovirus reactivation at a median of 46 days (range,17-101) after transplantation. Summary/Conclusion: In our experience, allogeneic P-BMT from matching sibling donors induces fast neutrophil and platelet engraftment but seems to be associated with high rate of acute GVHD. Keywords: Granulocyte colony-stimulating factor (G-CSF), Bone Marrow, Bone marrow transplant, Graft-versus-host disease (GVHD)