Thrombopoietin Receptor Agonists in Treatment of Idiopathic Thrompocytopenic Purpura (Primary Immune Thrombocytopenia): Efficacy and Safety in Everyday Clinical Practice

Background & Aims. The use of thrombopoietin receptor agonists (aTPO-r) is a new approach to the treatment of patients with idiopathic thrompocytopenic purpura (ITP) irresponsive to other methods. Data on the efficacy and safety of aTPO-r outside the frames of clinical trials are limited. The aim of the study is to evaluate the efficacy of the therapy in the routine clinical practice as the second and subsequent lines of therapy, as well as the frequency and nature of complications of the treatment in chronic ITP patients. Methods. Data on 58 adult patients (median age: 56 years) with chronic ITP were retrospectively evaluated; 43 (74 %) of them were treated with romiplostim and 15 (26 %) patients received eltrombopag. Two or more lines of prior therapy were ineffective in 19 (33 %) patients (14 from the romiplostim group and 5 from the eltrombopag group). aTPO-r was prescribed and adjusted according to the prescription guidelines. The efficacy of the treatment was assessed based on the platelet response and the possibility of achieving a sustained response after discontinuation of the therapy. Hemorrhagic manifestations were classified according to the WHO bleeding scale. The safety assessment is conducted by identifying adverse events (AEs) and lab test abnormalities. Treatment-related adverse events was assessed according to the Common Terminology Criteria for Adverse Events (CTCAE) v3.0. Results. The therapy with aTPO-r was effective in 49 (84 %) patients, including 36 patients (84 %) treated with romiplostim and 13 patients (87 %) with eltrombopag. The median dose to maintain a response was 3.7 mg/kg and 44 mg, respectively. A stable remission was achieved in 4 patients after discontinuation of romiplostim and 1 patient after discontinuation of eltrombopag. aTPO-r resistance was diagnosed in 9 (16 %) patients: 7 (16 %) of them were from the romiplostim group and 2 (13 %) from the eltrombopag group. Complete arrest of bleeding was achieved in 43 (88 %) responders and its reduction to grade I was achieved in the remaining 6 (12 %) of them. The most frequent AEs of romiplostim therapy were headache, arthralgia and dermatitis; and the treatment with eltrombopag caused hepatotoxicity, headache, and nausea. The severity of events did not lead to complete discontinuation of the therapy in any case. Different types of thrombotic complications were diagnosed in 3 patients (5.2 %). Conclusion. The therapy with aTPO-r is an effective and safe method for the treatment of patients with chronic ITP in the second and subsequent lines of therapy