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.

Inclusion criteria

• Diagnosis of any of the following B-cell chronic LPD, as defined by WHO 2008 classification: small lymphocytic lymphoma/chronic lymphocytic leukemia, follicular lymphoma, marginal zone lymphoma, mantle cell lymphoma, lymphoplasmacytic lymphoma, hairy cell leukemia, Hodgkin's lymphoma.
• Occurrence of ITP diagnosed on the basis of predefined criteria.
• Not likely to necessitate any cytotoxic treatment for the following 6 months, according to clinical stage and performance status.
• Platelet count less than 30,000/µL; patients with platelet count between 30 and 50,000/µL only in case of bleeding signs or symptoms.
• Age greater than or equal to 18 years.
• Absence of a personal or family (up to first degree relatives) history of venous or arterial thromboembolism.
• ECOG performance status ≤2.
• Adequate liver and renal function.
• Absence of active Hepatitis B (HBsAg+ or HBV-DNA+), Hepatitis C (HCV-Ab+), or HIV infection.

• Provided informed consent. 10) Negative pregnancy test or lactation 11) No antiplatelet or anticoagulant ongoing treatments

Exclusion criteria

• Subjects with any clinically relevant abnormality, other than LPD or ITP, or any other medical condition or circumstance, which in the opinion of the investigator makes the subject unsuitable for participation in the study.
• Subjects with any concurrent malignant disease other that the LPD and/or a recent history of cancer treatment with systemic chemotherapy and/or radiotherapy. Exception: Subjects with a history of completely resected non-melanoma skin cancer or successfully treated in situ carcinoma are eligible.
• Subjects with screening bone marrow fibers of either MF Grade 3 using European Consensus scale or Grade 4 using Bauermeister scale (see Appendix 1).
• Subjects with a QTc >450 msec or > 480 msec for subjects with Bundle Branch Block.
• Subjects with recent history of alcohol/drug abuse as determined by the investigator.