The advantages and risks of ruxolitinib for the treatment of polycythemia vera.

Introduction Polycythemia vera is a myeloproliferative neoplasm characterized by an increased red blood cell mass, risk of thromboembolic events, and of transformation into secondary myelofibrosis and acute leukemia. The goal of treatment is to reduce the risk of fatal cardiovascular events reducing the hematocrit level with phlebotomies and low-dose aspirin. In high-risk patients (age >60 years or previous thromboembolic events) cytoreductive therapy is indicated. In this setting, resistance and/or intolerance is common. Areas covered Authors searched Medline, Embase, archives from the EHA and the ASH annual congresses from 2014 onward about ruxolitinib treatment in PV patients. Two trials (RESPONSE and RESPONSE2) have documented the efficacy and safety of ruxolitinib. The drug is able to persistently control the hematocrit level and symptoms (due to increased cytokine levels, increased viscosity, and increased splenomegaly), to reduce WBC counts and the rate of thromboembolic events, to increase the quality of life. Expert opinion Although ruxolitinib has entered into the clinical practice, the real-life incidence of resistant/intolerant patients, the long-term safety, and the activity on thromboembolic events (associated or not to a reduction of the molecular burden) remains to be conclusively determined. More information extrapolated by registries are required to shed light on the missing information.