Sustained remission after TPO-RA discontinuation in chronic ITP

High rates of sustained remission were achieved in patients with chronic primary immune thrombocytopenia (ITP) who discontinued thrombopoietin-receptor agonist (TPO-RA) therapy after achieving a complete response (CR). The results of the STOPAGO study support progressive dose reductions of TPO-RAs in patients who achieved a stable CR on this treatment [1].

A recent prospective study observed durable remissions in approximately 30% of the patients with ITP after TPO-RAs discontinuation [2]. However, the study population included patients with newly diagnosed ITP, in whom spontaneous remission may occur. Therefore, Prof. Matthieu Mahevas (Hôpital Henri-Mondor, France) and colleagues conducted the prospective, multicentre, interventional STOPAGO study (NCT03119974) to assess the proportion of patients with chronic or persistent ITP that display sustained remission after TPO-RA therapy discontinuation. Participants (n=49) received TPO-RA therapy (eltrombopag, n=40; romiplostim, n=9) for at least 3 months. Subsequently, a tapering protocol of 25 mg per 2 weeks or 1 μg/kg per week was initiated, until TPO-RAs were discontinued completely at week 10. The primary endpoint was the overall response at 24 weeks after treatment discontinuation.

At 24 weeks, the primary endpoint was reached for 56.2% of the participants. CR was achieved in 55.0% of the responders or 31.3% of the intention-to-treat population. After 52 weeks, the overall response rate of treatment discontinuation was 52.1%, with 56% of the responders achieving a CR. At week 24, bleeding events were reported in 61.9% of the patients who relapsed. However, no severe bleedings were reported. Notably, the median time of relapse after the initiation of the tapering protocol was 8 weeks. Few relapses occurred after these first 2 months.

Prof. Mahevas argued that the sustained remission rate among patients with chronic ITP who achieved a stable CR on TPO-RAs was unexpectedly high. He also emphasised that no severe bleedings occurred in the study population. Further studies should investigate the underlying mechanism of sustained remission to select eligible patients for a TPO-RA discontinuation strategy.

1. Mahevas M, et al. Rate of Prolonged Response after Stopping Thrombopoietin-Receptor Agonists Treatment in Primary Immune Thrombocytopenia (ITP): Results from a Nationwide Prospective Multicenter Interventional Study (STOPAGO). Abstract 583, ASH 2021 Annual Meeting, 11–14 December.
2. Lucchini E, et al. British Journal of Haematology. 2021;193(2):386–396.

 

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Posted on 4 February 2022