Catherine Bagot

Summary Few studies have reported the real‐world use of both romiplostim and eltrombopag in immune thrombocytopenia (ITP). TRAIT was a retrospective observational study aimed to evaluate the platelet responses and adverse effects associated with the use of these thrombopoietin receptor agonists (TPO‐RAs) in adult patients with ITP in the United Kingdom. Of 267 patients (median age at diagnosis, 48 years) with ITP (primary ITP [ n = 218], secondary ITP [ n = 49]) included in the study, 112 (42%) received eltrombopag and 155 (58%) received romiplostim as the first prescribed TPO‐RA. A platelet count ≥30 × 10 9 /L was achieved in 89% of patients with the first TPO‐RA treatments, while 68% achieved a platelet count ≥100 × 10 9 /L. Treatment‐free response (TFR; platelet count ≥30 × 10 9 /L, 3 months after discontinuing treatment) was achieved by 18% of the total patients. Overall, 61 patients (23%) switched TPO‐RAs, most of whom achieved platelet counts ≥30 × 10 9 /L with the second TPO‐RA (23/25 who switched from eltrombopag to romiplostim [92%]; 28/36 who switched from romiplostim to eltrombopag [78%]). TFR was associated with secondary ITP, early TPO‐RA initiation after diagnosis, the presence of comorbidity and no prior splenectomy or treatment with steroids or mycophenolate mofetil. Both TPO‐RAs had similar efficacy and safety profiles to those reported in clinical studies.