PS1106 A RETROSPECTIVE ANALYSIS OF IMMUNE THROMBOCYTOPENIA PATIENTS TREATMENT RESULTS AFTER SEQUENTIAL SWITCHING OF THROMBOPOIETIC RECEPTOR‐AGONISTS

Background: Immune thrombocytopenia (ITP) is an immune‐mediated disease characterized by increased platelet destruction and impaired platelet production with transient or persistent decrease in the platelet count and increased risk of bleeding. Romiplostim (R) and Eltrombopag (E) are the first thrombopoietic receptor‐agonists (TPO‐ra) with demonstrated efficacy against ITP. So far, very few data are available about the potential contribution of switching from romiplostim to eltrombopag or vice versa in terms of efficacy or tolerance. Aims: To evaluate the reasons for and result of TPO‐ra switching in adult ITP patients Methods: We retrospectively analyzed all patients who received sequential treatment with both TPO‐RA between 2014 and 2018 in Moscow city hematology center (Botkin hospital). Results: Thirty‐three pts with primary ITP were included; 19 received first Romiplostim and 15 received first Eltrombopag. Reasons for switching were inefficacy (n = 30) and adverse events (n = 3). All patients (33) had previously received multiple courses of corticosteroids and IV Ig infusions, four (10%) received immunosuppression (rituximab), and five (14%) performed splenectomy. The median platelet count at the administration of the second TPO‐ra was 17x10 9 /l (range 3–25x10 9 /l). Twenty‐five (76%) patients had bleeding symptoms before the second TPO‐ra administration. From 33 included patients partial response (> 50x10 9 /l without platelet transfusions and bleeding) was achieved in 16 (70%). PR was seen in sixteen from 19 (84%) in E to R group and seven from 15 (47%) in R to E group. Complete response (>100x10 9 /l without pl. transfusions and bleeding) were achieve in 17 from 33 (52%). Twelve pts from 19 (63%) achieve CR in E to R group and five from 15 (30%) in R to E group. Two of 17 (10%) pts achieved a CR within 1–3 months, 11 (67%) pts in 3–12 months, and four (23%) pts later than 1 year from the start of switching to second TPO‐ra therapy. Three pts (2 in E group due to repeated thrombosis, and 1 in R group due to persistent increased liver enzymes) with recommendation of switching to second TPO‐ra due to adverse events resolved rapidly and maintained remission on alternative drug. In nine pts (28%) the switching to second TPO‐ra therapy was ineffective (blood platelet level was less than 30x10 9 /l pl). All of them were resistant to first TPO‐ra. Summary/Conclusion: Our results confirmed that switching from one thrombopoietic receptor‐agonist to another could be beneficial for patients with chronic immune thrombopenia who failed to respond. Yet longer follow‐up and larger number of pts enrolled are required to fully assess the potential benefits of such therapy change.