Efficacy of Eltrombopag to Improve Thrombocytopenia of MYH9-related Disease

The term MYH9-related disease (MYH9RD) includes four genetic disorders: May-Hegglin anomaly, Sebastian syndrome, Fechtner syndrome, and Epstein syndrome. All these disorders derive from mutation of a unique gene, named MYH9, and they have been recognized as different clinical presentations of a single illness that was named MYH9RD. All patients affected by MYH9RD present since birth with thrombocytopenia, which can result in a variable degree of bleeding diathesis; some of them subsequently develop additional clinical manifestations, such as renal damage, sensorineural hearing loss, and/or presenile cataracts. Eltrombopag is an oral thrombopoietin receptor agonist that stimulates proliferation and differentiation of megakaryocytes, the bone marrow cells that produce blood platelets. This drug is effective in increasing platelet count in healthy volunteers, as well as in patients affected by some acquired thrombocytopenias, such as idiopathic thrombocytopenic purpura and HCV related thrombocytopenia. The purpose of this study is to determine if eltrombopag, administered orally at the dose of 50 or 75 mg/daily for up to 6 weeks, is effective in increasing platelet count of patients affected by MYH9RD. Further aims of this study are to test if eltrombopag is effective in reducing bleeding tendency of MYH9RD patients; to evaluate safety and tolerability of eltrombopag in patients with MYH9RD; to evaluate in vitro function of platelets produced during therapy in patients responding to this drug.