Clinical effects of granulocyte colony-stimulating factor administration and the timing of its initiation on allogeneic hematopoietic cell transplantation outcomes for myelodysplastic syndrome.

Granulocyte colony-stimulating factor (G-CSF) accelerates neutrophil recovery after allogeneic hematopoietic cell transplantation (HCT). However, the optimal use of G-CSF and the timing of its initiation after allogeneic HCT for myelodysplastic syndrome (MDS) according to graft type have not been determined. This retrospective study aimed to investigate the effects of using G-CSF administration and the timing of its initiation on transplant outcomes in adult patients with MDS undergoing allogeneic HCT. Using Japanese registry data, we retrospectively investigated the effects of G-CSF administration and the timing of its initiation on transplant outcomes among 4140 adults with MDS after bone marrow transplantation (BMT), peripheral blood stem cell transplantation (PBSCT), or single-unit cord blood transplantation (CBT) between 2013 and 2022. Multivariate analysis showed that early (days 0 to 4) and late (days 5 to 10) G-CSF administration significantly accelerated neutrophil recovery compared with no G-CSF administration following BMT, PBSCT, and CBT, but there was no benefit of early G-CSF initiation for early neutrophilic recovery regardless of graft type. Late G-CSF initiation was significantly associated with a higher risk of overall chronic GVHD following PBSCT (hazard ratio [HR], 1.63; 95% confidence interval [CI], 1.18 to 2.24; P = .002) and CBT (HR, 2.09; 95% CI, 1.21 to 3.60; P = .007) compared with no G-CSF administration. Late G-CSF initiation significantly improved OS compared with no G-CSF administration only following PBSCT (HR, 0.74; 95% CI, 0.58 to 0.94; P = .015). However, G-CSF administration and the timing of its initiation did not affect acute GVHD, relapse, or non-relapse mortality, irrespective of graft type. These results suggest that G-CSF administration significantly accelerated neutrophil recovery after BMT, PBSCT, and CBT, but increased risk of overall chronic GVHD after PBSCT and CBT. However, the effect of early and late G-CSF initiation on transplant outcomes needs further study in adult patients with MDS.