Imatinib (Gleevec(Registered Trademark)) to Treat Chronic Myelomonocytic Leukemia and Atypical Chronic Myelogenous Leukemia

The purpose of this study is to evaluate the safety and effectiveness of imatinib for improving blood counts in patients with chronic myelomonocytic leukemia (CMML) and atypical chronic myelogenous leukemia (CML). Although a number of agents have been used to treat these diseases, most patients do not respond to treatment. Imatinib has been shown in clinical trials to induce high rates of responses in patients with chronic phase CML. Imatinib has also been shown to be effective in inducing responses in a subset of patients with CMML and atypical CML and is also effective in a subset of patients with idiopathic hypereosinophilic syndrome (HES), another myeloproliferative disorder. Because patients with several different myeloproliferative diseases have been shown to experience dramatic responses to imatinib, we would like to determine what proportion of patients with atypical myeloproliferative diseases (CMML and atypical CML) will respond to this agent. Prior to enrollment, a thorough clinical evaluation will be performed. A baseline bone marrow will be obtained to exclude acute leukemia or lymphoma and to assess the degree and nature of the myeloproliferation. In order to minimize bone marrow suppression, other myelosuppressive drugs will be tapered and discontinued during the first week of therapy with imatinib. Complete blood counts will be performed weekly for the first month and every other week thereafter. Clinical assessments will be performed every three months to assess for continued response.