Thrombopoietin receptor agonists for the treatment of severe persistent and chronic immune trombocytopenia in children: clinical data of Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology, Immunology

Abstract

Thrombopoietin receptor agonists (TPO-RA) – romiplostim and eltrombopag – changed considerably the therapeutic options for severe persistent and chronic immune thrombocytopenia (ITP). The article presents the results of a retrospective study of TPO-RA efficacy and safety in patients under 18 years of age. The study was approved by the Independent Ethics Committee and Scientific Council of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology. Sixty-eight children had a total of 89 courses of TPO-RA (44 romiplostim and 45 eltrombopag). Their median age was 6.5 years. The median ITP duration was 15.8 months. All patients received previous ITP therapy (1–6 lines). Before the initiation of TPO-RA, the majority of patients had thrombocytopenia with bleeding. In most cases, the platelet response was achieved within the first 2 months of treatment. The average effective doses of romiplostim and eltrombopag were 10 mg/kg per week and 75 mg per day, respectively. Half of patients in romiplostim group and 62% of patients in eltrombopag group did not require extra therapy. The majority of patients (75.6–81.8%) achieved an overall response, but only near 50% achieved a durable (more than 24 weeks) platelet response. Six patients sustained the response after TPO-RA discontinuation. The most common adverse events (AE) of TPO-RA therapy were transient elevation in hepatic enzymes in eltrombopag group (28.9%) and thrombocytosis (18.2–22.2%) in both groups. In 6 cases the therapy was discontinued due to AEs. Two AEs were serious. Our results demonstrate that TPO-RA could safely increase platelet counts and decrease the risk of spontaneous life-threatening bleeding in nearly half of children with severe persistent and chronic ITP. TPO-RA could help to avoid long-term immunosuppressive therapy and splenectomy or delay them and the ITP remission is possible in some cases.