A Single-Center Study of Long-Term Efficacy and Discontinuation Patterns of Thrombopoietin Receptor Agonists in Chronic Immune Thrombocytopenia

Introduction

Thrombopoietin receptor agonists (TPO-RAs) have shown promising efficacy in the management of persistent or chronic immune thrombocytopenia (ITP), as second-line treatment, whereas sustained responses after TPO-RA discontinuation have also been reported. We present real-world data of TPO-RA-treated chronic ITP patients in a single center.

Methods

This retrospective study was conducted at the Hematology Unit of the First Department of Internal Medicine of the National and Kapodistrian University of Athens, Laikon General Hospital in Athens, Greece. Data were obtained from consecutive adult patients with chronic/refractory primary ITP treated with TPO-RAs from January 2010 to June 2024. Complete response (CR), defined as platelet count ≥ 100 × 10⁹/L and absence of bleeding as well as durable response, defined as platelet count ≥ 30 x 10⁹/L and at least doubling of the baseline count, were evaluated in these patients after initiation of TPO-RA treatment.

Results

A total of 52 patients were included. The median age was 52 (19-72) years and 70% were female. Patients had been previously treated with corticosteroids (100%), intravenous immunoglobulin (54%), immunosuppressants (21%), rituximab (8%), or splenectomy (17%). The majority of the patients (65%) received eltrombopag as initial TPO-RA treatment, while 35% were treated with romiplostim. The median time from diagnosis to TPO-RA treatment initiation was four years. The median duration of TPO-RA treatment was 48 months. CR was achieved in 52% of patients with TPO-RA treatment, whereas 23% of patients yielded durable responses. The median time to CR was 24 months. Ten patients (19%) who did not initially respond to eltrombopag, switched to another TPO-RA (90% avatrombopag), with 70% of them achieving CR and 20% yielding a durable response. The median time to CR after switching to a different TPO-RA was 16 months. Among all patients who achieved durable responses, a reduction in TPO-RA dose was achieved in 71%. Treatment discontinuation was observed in 58% of patients, due to either CR (90%) or poor response (10%). The median treatment-free period was 11 months, while treatment reinitiation due to loss of CR was noted in 11%.

Conclusion

TPO-RAs are highly effective in treating chronic ITP patients who are refractory to or relapse after first-line treatments. Furthermore, these agents can lead to sustained responses, thus allowing for treatment discontinuation and ultimately contributing to life quality improvement. Finally, switching to another TPO-RA may be beneficial for patients who do not initially respond.

No relevant conflicts of interest to declare.