Romiplostim, Rituximab and Dexamethasone as Frontline Treatment for Immune Thrombocytopenia

The purpose of this study is to determine the response rate and response duration with the combination of low-dose rituximab, romiplostim and high-dose dexamethasone.

Immune thrombocytopenia is an autoimmune disorder characterized by formation of autoantibodies against platelet antigens leading platelet destruction. Corticosteroids increase the platelet count in about 80 percent of patients. However, many patients have a relapse when the dose of corticosteroid is reduced. Debilitating side effects are common in patients who require long-term corticosteroid therapy to maintain the platelet count. Romiplostim, it is a small molecule agonist of the c-mpl (TpoR) receptor, which is the physiological target of the hormone thrombopoietin, has been shown to be effectively raise the platelet count in adult patients (aged 18 years and over) who have had their spleen removed or where splenectomy is not an option and have received prior treatment with corticosteroids or immunoglobulins, and these medicines did not work (refractory ITP). There are a few case reports where romiplostim an option as first line treatment for IT. The purpose of this study is to determine the response rate and response duration with the combination of rituximab (100 mg weekly four weeks), romiplostim (2mcg/Kg four weekly) and high-dose dexamethasone (40mg PO days 1-4) in untreated adult patients with \<30\*109/L platelet count diagnosed with immune thrombocytopenia. A complete response is defined as an increase in platelet counts to \>150×109/L on two consecutive occasions. A clinical response is defined as an increase in the platelet count between \>30×109/L on two consecutive measures and no bleeding. Duration of response is considered from the day of the initial administration to the first time of relapse (platelet count \<30×109/L) or to time of analysis Patients will be evaluated each week during 4 weeks and then every month for at least 6 months.