[Development of chronic myelogenous leukemia during treatment with TPO receptor agonist for ITP].

We report a 77-year-old Japanese man with idiopathic thrombocytopenic purpura (ITP) which developed into chronic myelogenous leukemia (CML) during treatment with eltrombopag, a thrombopoetin (TPO) receptor agonist, because the disease was refractory to prednisolone. Eltrombopag can induce a good reaction in terms of the platelet count. However, CML in the chronic phase developed in about 19 months in our present case. Dasatinib was administered because he had diabetes. However, a blastic crisis immediately occurred. He died despite switching to Nilotinib. Recently, the occurrence of myelofibrosis and hematological malignancies due to long-term use of TPO receptor agonists has become a concern. This is the first report of a TPO receptor agonist possibly contributing to CML onset and crisis.