Treatment of immune thrombocytopenia (ITP) with eltrombopag - Results of the 5th interim analysis of the study RISA

Background

Immune thrombocytopenia (ITP) is an autoimmune disorder characterized by isolated thrombocytopenia due to increased platelet destruction and decreased megakaryopoiesis. Eltrombopag (EPAG) is an oral thrombopoietin-receptor agonist, which is proved to be effective and safe in the treatment of ITP. Here we present data from the 5th interim analysis of the non-interventional prospective study RISA.

Methods

RISA is a prospective multicenter non-interventional study in Germany. It started in December 2015, enrollment stopped in December 2021, and the observational phase will end by December 2023. Dosage of EPAG and treatment corresponded to the Summary of Product Characteristics (SmPC) and routine of treating physicians. In addition to platelet counts and bleeding events, fatigue is also assessed by using the FACIT-Fatigue (FACIT-F) questionnaire. Statistical analysis is solely descriptive. Data cutoff for this 5th interim analysis was 11th Feb 2022

Results

302 of the enrolled patients received at least one dose of EPAG and completed at least one post baseline visit. Mean duration of ITP at baseline was 5.4±7.5 years. Mean age was 62.8±17.4 years. Median treatment duration was 14 months. Treatment with EPAG was carried out at a median dosage of 50 mg daily. Median platelet counts increased from baseline 34.0x109/L to 91.5x109/L within one month and remained stable above 90x109/L until the end of the observation period. The number of bleeding events per patient-year decreased, from 1.35 at baseline to 0.59 and 0.16 after one and two years, respectively. In contrast to the improvement in platelet count and incidence of bleeding events, no significant improvement in fatigue score was observed.

Conclusion

EPAG therapy in ITP effectively increases platelet counts and reduces bleedings. Our preliminary data show that about 82 % of patients responded to EPAG. This seems to be consistent with the results of the open extension study EXTEND [Wong RSM et al. Blood 2017; 130: 2527-36], in which a similarly high overall response rate (86%) was found. In general, treatment with EPAG was well tolerated, with no new safety signals from our data set. However, ITP-related fatigue needs further investigation.

Offenlegung Interessenkonflikt:

OM discloses honoraria from Amgen, Grifols, Novartis, ArgenX, and SOBI for lectures and andvisory boards; RS has nothing to disclose; TS discloses honoraria from Novartis, Amgen, Alexion, Janssen, AOP, Celgen/BMS, Sobi, ArgenX, Grifols, AstraZeneca; BF has nothing to disclose; MR discloses honoraria from Roche, Celgene, Abbvie, Janssen-Cilag; DK has nothing to disclose; MW has nothing to disclose; CvdH discloses honoraria from BMS, Novartis, AstraZeneca, Ipsen, Pierre Fabre, Böhringer Ingelheim, and Ipsen; SD has nothing to disclose; CW is employee of Novarits Pharma GmbH; MS has nothing to disclose.

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