Evaluation of the efficacy and safety of initial high-dose romiplostim for primary immune thrombocytopenia in the acute care setting

Romiplostim is a thrombopoietin receptor agonist indicated for previously treated primary immune thrombocytopenia (ITP) that leads to dose-dependent increases in platelet counts. Higher initial doses than the standard starting dose of 1 μg/kg may have the potential to lead to faster platelet responses. We conducted a single-center, retrospective, observational study to evaluate the efficacy of romiplostim dosing strategies in adult patients with primary ITP who initiated romiplostim in the acute care setting. Patients were classified into low-dose (<3 μg/kg) or high-dose (≥3 μg/kg) based on the initial weight-based dose administered. The primary outcome was time to achieve a platelet count greater than 30 × 10 9 /l. Secondary objectives included time to platelet count greater than 50 × 10 9 /l, healthcare resource utilization, thrombotic events, and bleeding incidents. Sixty-five patients were included in the study. Patients in both dosing cohorts achieved a platelet response of greater than 30 × 10 9 /l at a median of 7 days ( P = 0.871). There were no significant differences in healthcare resource utilization or safety events between dosing cohorts. Initial high-dose romiplostim for acute ITP did not demonstrate an improvement in time to platelet response compared to initial low-dose romiplostim.