A large observational study of patients with primary immune thrombocytopenia receiving romiplostim in European clinical practice.

Objective Romiplostim has maintained long-term platelet counts in patients with immune thrombocytopenia (ITP) for up to 5 years in clinical studies. This prospective observational study aimed to describe romiplostim utilisation and outcomes in European clinical practice. Methods Adults with primary ITP who received romiplostim in routine care were eligible. Results Three-hundred and forty patients were eligible for analysis, of whom 299 (88%) completed the two-year observation period. The median age was 62 years, with 43% of patients aged ≥65 years, and two-thirds of patients initiated romiplostim before splenectomy. The median average weekly dose of romiplostim was 2.8 μg/kg. The median baseline platelet count was 20 × 109/L, which increased after 2 weeks of romiplostim treatment and remained >50 × 109/L thereafter. After romiplostim initiation, there was a decrease in rates of grade ≥3 bleeding events (from 12 to 2 per 100 patient-years) and ITP-related hospitalisations (from 87 to 33 per 100 patient-years). The rate of thrombotic events was 2 per 100 patient-years and bone marrow fibrosis occurred in two patients. Conclusions Romiplostim dosing, effectiveness, and safety in an unselected real-world ITP population seemed comparable with that observed in clinical studies. This article is protected by copyright. All rights reserved.