Romiplostim-Free Response in Immune Thrombocytopenia: Experience in Cuenca-Ecuador

Background: Thrombopoietin analogues (TPO) achieve overall response rates of 75-80%, and in 60% are sustained with continuous administration for 6 months. In 10-30% of patients, response is maintained despite discontinuation of these drugs. Objectives: -Evaluate the percentage of patients with Romiplostim-free response criteria: platelet count ≥50,000/µL for at least six months (twenty-four consecutive weeks) in the absence of romiplostim and any other concomitant or rescue treatment for immune thrombocytopenia. -Determine sustained response factors after discontinuation of Romiplostim Materials and methods: Retrospective, analytical study in patients older than fifteen years with immune thrombocytopenia who accessed to romiplostim. Patients with systemic lupus erythematosus were included. Data was collected from the digitized medical records of a tertiary level hospital in Cuenca (Ecuador). The nonparametric Mann-Whitney U test using SPSS version 25 software (Chicago, IL) was used to establish comparisons between potential factors that may be associated with Romiplostin-free response. Results: a) Twenty-one patients with immune thrombocytopenia received romiplostim between August 2015 and February 2023 at some point.b) The median time from ITP diagnosis was 93 months (Q1 percentiles of 51.5 and Q3 106.5) for romiplostim use.c) The median duration of treatment with Romiplostim was 61 months (Q1 percentile range 18.5 and Q3 79).d) 37.5% (n:6) met Romiplostim-free response criteria, with a median follow-up of 7 months (Q1 percentile range of 3.5 and Q3 27.1). For this analysis, five patients were excluded (three who switched to eltrombopag, one who was lost to follow-up due to the health pandemic, one who had no response).e) One patient restarted Romiplostim after twenty months of sustained response.f) 23.8% (n:5) were able to discontinue romiplostim without restarting it. Conclusion(s): 1) 37.5% achieved Romiplostim-free response criteria 2) No predictors of sustained response were found for Romiplostim discontinuation (p>0.05). Bibliography: 1. Cooper N: Tapering and Discontinuation of Thrombopoietin Receptor Agonist Therapy in Patients with Immune Thrombocytopenia: Results from a Modified Delphi Panel. Acta Haematologica. 2021; 144:418-426 2. Iino M: Treatment-free remission after thrombopoietin receptor agonist discontinuation in patients with newly diagnosed immune thrombocytopenia: an observational retrospective analysis in real-world clinical practice