Pb2612: united kingdom retrospective observational study of romiplostim and other treatments in early immune thrombocytopenia

Topic: 32. Platelet disorders Background: As of 2021, the thrombopoietin receptor agonist (TPO-RA) romiplostim is licensed for adults with immune thrombocytopenia (ITP) across all disease phases, including duration ≤1 year refractory to first-line treatments. While aligned with treatment guidelines, real-world UK data on this indication are lacking. Aims: To assess the response to romiplostim, we performed a retrospective UK-wide study of real-world treatment patterns in adults with primary ITP ≤1 year from diagnosis between 2 July 2015 and 23 March 2020. Methods: Recruited patients were divided into those who either did (Group 1) or did not (Group 2) receive romiplostim during the first year from diagnosis. TPO-RAs, including eltrombopag, could be received in either group after the first year (excluding eltrombopag in the first year). All efficacy and safety analyses were descriptive. Results: Seventy-eight patients enrolled at seven UK sites; Group 1 (n=13) 62% female, median (min-max) platelets 4 (2-44)×109/L and Group 2 (n=65) 59% female, median (min-max) platelets 7 (0-108)×109/L (Table). In Group 1, romiplostim was initiated (off-license) at a median of 6 weeks with a median treatment duration of 63 weeks; 2/13 received romiplostim first-line and 11/13 as the second treatment or later. Romiplostim treatment continued in 8/13 patients at study end. Other treatments in Group 1 in more than one patient included: prednisolone (n=11), mycophenolate mofetil (MMF, n=5), IVIg (n=4), and rituximab (n=3). In Group 2, two patients (3%) received no treatment; 33 patients (51%) received corticosteroids ± IVIg ± tranexamic acid only without further escalation; 26 patients (40%) required MMF or rituximab. In the second year, six patients (9%) in Group 2 required a TPO-RA. The median treatment duration was shorter for Group 1 vs 2 for prednisolone (3 vs 10 weeks for those discontinuing prednisolone) and MMF (13 vs 39 weeks). By the end of the 2-year treatment period, median (interquartile range) platelet counts had increased to 157 (81-275) and 122 (81-202)×109/L in Groups 1 and 2, respectively. During the observation period in Groups 1 and 2, respectively, bleeding episodes occurred in 54% and 63% of patients, and rescue therapies were required by 39% and 31% of patients. The mean number of rescue therapies/patient was 0.6 and 0.8 in Groups 1 and 2, respectively. Thromboembolic events occurred in one patient in each group (Group 1: sub-acute left lower limb arterial ischemia; Group 2: stroke).Summary/Conclusion: These findings support further exploring the earlier use of romiplostim for adult patients with primary ITP. Keywords: Immune thrombocytopenia (ITP), Thrombopoietin (TPO), Thrombocytopenia, Platelet