PLATON: use of romiplostim to treat chronic primary immune thrombocytopenia

Chronic primary immune thrombocytopenia (ITP) is an autoimmune disease involving the formation of antibodies to thrombocytes, leading to increased platelet destruction and chronic thrombocytopenia. Additionally, impaired platelet production is due to relative thrombopoietin deficiency. Romiplostim, a thrombopoietin receptor agonist, normalized platelet counts in affected patients in randomized controlled trials and real-world observational studies. The present study collected real-world practice data from Central and Eastern Europe, i.e. Slovakia, Slovenia, Bulgaria, Russia, and Czech Republic, between December 2010 and July 2017. This was an ambidirectional observational, noninterventional cohort study within the approved romiplostim indication. One-hundred patients were analyzed. Prior to romiplostim start, 98% had received other ITP medications and, in the prior 6 months, 40% had experienced bleeding events. Romiplostim was started 1.92 years (median) after ITP diagnosis. The median mean on-study dose was 2.62 µg/kg/week. During romiplostim treatment, platelet counts rapidly normalized to >50 × 10⁹/L, 20% of patients experienced bleeding events (none grade 3/4), and 13% required splenectomy. At the end of study, 25% of patients were in remission. One patient experienced serious adverse drug reactions (thrombosis, dysphagia), none were fatal. In conclusion, romiplostim dosing, effectiveness and safety in these unselected ITP patients seemed comparable with observations in clinical trials and similarly designed observational studies.