Eltrombopag for the Treatment of Immune ThrombocytoPenia (ITP) Secondary to Chronic Lymphoproliferative Disorders (LPDs)

The denomination of Chronic Lymphoproliferative Disorders (LPD) encompasses a variety of indolent lymphomas grouped into a single clinical category and, as such, this terminology is not included in the current WHO classification. With indolent lymphomas clinicians refer to those lymphomas not associated with an aggressive clinical course and in which often treatment can be delayed. Specifically the following lymphomas by the WHO classification will be considered among indolent lymphomas: small lymphocytic lymphoma/chronic lymphocytic leukemia, follicular lymphoma, marginal zone lymphoma, mantle cell lymphoma, lymphoplasmacytic lymphoma, hairy-cell leukemia, Hodgkin's lymphoma. In 1 to 5% of the different LPDs (lowest in follicular lymphoma, highest in chronic lymphocytic leukemia) a clinically relevant thrombocytopenia, often complicated by bleeding symptoms, may complicate the clinical course, frequently still when the tumor burden is low and not demanding treatment. This thrombocytopenia, when not accompanied by massive bone marrow tumor infiltration or not secondary to chemotherapeutic treatment, is thought to share an immune pathogenic mechanism similar to primary immune thrombocytopenia (ITP). With conventional treatments (i.e. iv Ig, steroids) the overall response rate of ITP secondary to LPD is generally lower than in primary ITP, and usually not higher than 50% (95% CI 27-72). Therefore, any new treatment having a response rate above 50% but not inferior than 20% could be considered a promising treatment for ITP secondary to LPD. Furthermore, no significant platelet increase is expected without treatment in ITP secondary to LPD. Eltrombopag which has proved very effective in primary ITP could be effective also in ITP secondary to LPDs. This novel ITP specific treatment might spare these patients not only from bleeding risk but also from toxic or inappropriate cytotoxic therapies, not otherwise demanded by the burden of the underlying disease. Phase 2, single arm, open-label, prospective, multicenter, safety/efficacy study.