This is a multicenter, retrospective, European study to evaluate the standards of use of thrombopoietin receptor agonists (TPO-RA) in adult patients with primary immune thrombocytopenia (ITP). Data will be collected through a retrospective chart review of patients with ITP who started TPO-RA treatment between January 2014 and December 2018.

Each of the 18 designated sites in the UK, Spain, Italy, Norway, France and Switzerland will collect data from patients with ITP who meet the inclusion criteria and agree to participate. The aim of the study is to provide a realistic and broad view of the use of TPO-RA in Europe at a time when so many new molecules are being tested in this disease, without being biased by the clinical practice of any particular center. The information to be analyzed will include patient or disease characteristics in the selection of TPO-RA, long-term efficacy and safety data of these agents, and treatment-free responses, among others.

This project was initiated in 2022 and will be completed in the middle of next year, when data from approximately 350 patients will have been collected. Currently, centers from the 6 European countries are actively recruiting and results of the study will be published by the end of 2024.

The project is coordinated by ERCI founding member Maria Luisa Lozano, from the Hospital Universitario Morales Meseguer, Universidad de Murcia, Spain, and is conducted in collaboration with the Hematology Project Foundation, Vicenza, Italy.