Page 23 - Haematologica March 2020

Editorials
treated with 50mg eltrombopag for three weeks, and those who did not achieve a platelet count of >100x109/L received an additional three weeks of treatment at 75mg once daily. Five patients achieved a platelet count of >100x109/L with the 50mg dose and an additional three achieved this with the 75mg dose. Overall, 67% of patients achieved a platelet count of >100x109/L, 25% achieved a minor response, and a single patient did not respond. The treatment was well tolerated, and the bleeding symptoms resolved in 8 of 10 patients who pre- sented these at study entry.6
Since it is known that in most forms of inherited thrombocytopenia the megakaryocytes respond to TPO receptor agonists,7 the next logical step was to investigate these agents for the treatment of other forms of inherited thrombocytopenia, and this is what Zaninetti et al. have done.8 In this issue of the Journal, they report on their multicenter prospective investigation of eltrombopag in patients with five different types of inherited thrombocy- topenia. A total of 24 patients with MYH9-related dis- ease, ANKRD26-related thrombocytopenia, X-
linked/Wiskott-Aldrich syndrome, monoallelic Bernard- Soullier syndrome, and ITGB3-related thrombocytopenia were included. Patients awaiting procedures received an escalating dose of 50-75mg eltrombopag for 3-6 weeks, while individuals with active bleeding received an esca- lating dose of 25-75mg for up to 16 weeks (Figure 1). The responses varied between the different defects, but over- all 48% of the patients responded, achieving a platelet count of over 100x109/L. All four patients who were experiencing mucosal bleeding on entry, stopped bleed- ing following the eltrombopag treatment. The treatment with eltrombopag was well tolerated, but one patient with Wiskott Aldrich syndrome discontinued the treat- ment due to deterioration of his eczema.8
The trial by Zanetti et al. excluded some patients with inherited thrombocytopenia and predisposition to hema- tologic malignancy, such as those with mutations in the RUNX1 (previously known as AML1) and ETV6 genes; ANKRD26 patients were, however, included. The evi- dence that TPO receptor agonists accelerate disease pro- gression is controversial. A study of the use of the TPO
Figure 1. Outline of the phase II clinical trial using eltrombopag in patients with inherited thrombocytopenia.
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