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 yr 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 2-yr observation period. The median age was 62 yr, with 43% of patients aged ≥65 yr, 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 wk 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.