Treatment-free remission after thrombopoietin receptor agonist discontinuation in patients with newly diagnosed immune thrombocytopenia: an observational retrospective analysis in real-world clinical practice.

Thrombopoietin receptor agonists (TPO-RAs) are used for treatment of chronic immune thrombocytopenia (ITP). Several studies have shown that TPO-RAs induce remission and sustained response, despite long-term discontinuation of therapy. Furthermore, TPO-RAs are effective in patients with newly diagnosed ITP. Here, we retrospectively assessed all patients with ITP who received TPO-RAs in our hospital, focusing on newly diagnosed, non-splenectomized patients who had discontinued TPO-RAs due to sustained complete response (CR, platelet count ≥ 100 × 109/L). Moreover, we explored predictive factors related to sustained treatment-free remission (TFR) without additional ITP treatment. Seventy-seven consecutive patients with ITP received TPO-RAs from 2011 to 2018. Twenty-seven newly diagnosed patients achieved CR and discontinued TPO-RAs. The overall response and discontinuation rates in all patients with ITP were 79.2% and 41.6%, respectively. In newly diagnosed patients who discontinued TPO-RAs, the 2-year TFR rate, cumulative incidence of loss of CR, and response (R) rate (platelet count ≥ 30 × 109/L) were 66.4%, 46.7%, and 34.0%, respectively. Patients who achieved R within 14 days from the start of TPO-RA administration exhibited a higher 2-year TFR rate, compared with patients who did not (87.5% vs. 48.5%, p = 0.0106). In conclusion, patients with newly diagnosed ITP who achieve sustained response should consider discontinuation of TPO-RAs.