Sunitinib Induced Immune Thrombocytopenia

Sunitinib is an orally administered multi-targeted tyrosine kinase inhibitor and has been approved for the treatment of advanced renal cell carcinoma (RCC). It is well known that sunitinib induces hematologic adverse events, such as neutropenia, anemia, and thrombocytopenia, primarily through myelosuppression. Here, we report that the first case of immune-thrombocytopenia occurred in a patient receiving sunitinib for the treatment of metastatic RCC. The thrombocytopenia was refractory to repeated platelet transfusion. The bone marrow aspiration study revealed an increased number of megakaryocytes. No thrombotic microangiopathy was seen. The thrombocytopenia was successfully treated with high-dose corticosteroid, although intravenous immunoglobulin administration was not effective. These findings suggest that an immune-mediated mechanism was responsible for the thrombocytopenia in this patient, which developed during sunitinib administration.