PB2253 CHARACTERIZATION OF A POPULATION OF PATIENTS WITH MULTI‐REFRACTORY IMMUNE THROMBOCYTOPENIA: RESPONSE QUALITY AND DURATION WITH SEQUENTIAL THERAPY
Authors: F. Ferreira, M. J. Teles, C. Constanço, H. M. Silva, R. Salvado, A. Roque, L. F. Araújo, L. Ribeiro, M. Lopes, J. Coutinho
Journal: HemaSphere (2019)

Background: Immune Thrombocytopenia (ITP) has a significant impact on the quality of life of patients, particularly in patients that do not respond to several therapeutic lines. In the absence of clear recommendations regarding the best therapeutic sequencing and the lack of robust factors to predict response to treatment, it is relevant to evaluate, in a real‐life context, the efficacy of the different available therapies. Aims: The aim of this study is to evaluate the platelet response after therapy in patients with multi‐refractory ITP. Methods: Retrospective data collection from clinical files of outpatients with multi‐refractory ITP in 4 Portuguese terciary centers, treated at any time with thrombopoietin analogues (TPO‐Ra) until september 30 2018. Results: A total of 104 patients were evaluated, 78.8% with chronic ITP, with a median duration of ITP of 7.5 years (1.0‐58.0). Median age was 53 (2‐86) years old, 11.5% (n = 12) patients were diagnosed in pediatric age, 67.3% (n = 70) were female, and 95.5% (n = 99) have been treated with 3 or more therapeutic lines. Only 1 patient was not treated with first‐line corticosteroid therapy due to acquired immunodeficiency. The overall response rate, defined as platelets&gt;50x10 9 /L for at least 8 weeks, was 36% (n = 90) for corticotherapy, 49% (n = 45) for splenectomy, 22% (n = 23) for rituximab, 59% (n = 89) for eltrombopag, 63% (n = 23) for romiplostin and 12.5% (n = 32) for therapies more rarely used: azathioprine (n = 11), danazol (n = 10), CSA (n = 6), MFF (n = 3) and dapsone (n = 2). The response rates for eltrombopag and romiplostim in splenectomized patients were 48.9% and 22.2%, respectively. The median duration of response to splenectomy was 72.3 months and to rituximab was 6 months. Regarding to TPO‐Ra therapy, the median duration of response was not yet reached in our population, and almost half of patients are still under eltrombopag therapy (n = 41, 41.8%). In 35% of patients under eltrombopag therapy it was possible to suspend it after a median of 102 days, with maintenance of platelet response; in 12 patients on romiplostim, discontinuation of the therapy occurred after a median of 288.5 days, and 10 of these patients switched to eltrombopag. Summary/Conclusion: This retrospective study included a Portuguese patient population followed due to multi‐refractory ITP. The best response rates were obtained with splenectomy and TPO‐Ra and, in this last group, the responses were lower in previously splenectomized patients, which is not according to the literature. Rituximab response rates are lower than the ones expected for an unselected population; one possible explanation is the small number of patients treated and the selection of patients particularly difficult to treat. In 35% of patients treated with eltrombopag, it was possible to maintain response after discontinuation of therapy, as expected. These results should be considered together with the known safety profile of the different therapies and patients preferences. Long‐term prospective assessment remains relevant.