Different impacts of granulocyte colony‐stimulating factor administration on allogeneic hematopoietic cell transplant outcomes for adult acute myeloid leukemia according to graft type

We retrospectively evaluated the impacts of using granulocyte colony‐stimulating factor (G‐CSF) and its timing on posttransplant outcomes for 9766 adults with acute myeloid leukemia (AML) between 2013 and 2022 using a Japanese database. We separately evaluated three distinct cohorts based on graft type: 3248 received bone marrow transplantation (BMT), 3066 received peripheral blood stem cell transplantation (PBSCT), and 3452 received single‐unit cord blood transplantation (CBT). Multivariate analysis showed that G‐CSF administration significantly accelerated neutrophil recovery after BMT, PBSCT, and CBT. However, it was associated with a higher risk of grades II–IV acute graft‐versus‐host disease (GVHD) across all graft types. Moreover, an increased incidence of overall chronic GVHD was observed with G‐CSF administration in BMT and CBT patients, but not in PBSCT patients. G‐CSF administration significantly improved overall survival (OS) and leukemia‐free survival (LFS) only following CBT. Regarding the timing of G‐CSF, in comparison with late initiation of G‐CSF (Days 5–10), early initiation (Days 0–4) did not provide benefits for hematopoietic recovery regardless of graft type. In contrast, late initiation was significantly associated with a lower risk of grades II–IV acute GVHD and better OS and LFS in CBT patients. These data demonstrated that G‐CSF administration accelerated neutrophil recovery and increased the risk of grades II–IV acute GVHD across all graft types, but significantly improved survival outcomes but only following CBT. Therefore, routine use of G‐CSF should be considered for CBT in adult patients with AML.