This is a retrospective observational study evaluating the efficacy and safety of romiplostim for promoting platelet engraftment in patients who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) at Tongji Hospital Affiliated to Tongji Medical College of Huazhong University of Science and Technology between January 2025 to May 2026. Medical records were reviewed to collect data on platelet recovery time, transfusion requirements, and adverse events. The primary endpoint was time to platelet engraftment. Secondary endpoints included platelet recovery kinetics, transfusion requirements, transplant-related complications, and safety outcomes.No interventions were assigned as part of this study.