Contemporary approach to essential thrombocythemia and polycythemia vera

Management of polycythemia vera and essential thrombocythemia requires understanding of the key concepts regarding diagnosis, risk stratification, and management.

Essential thrombocythemia and polycythemia vera are among the Philadelphia chromosome negative myeloproliferative neoplasms. They are characterized by overproduction of blood cells and their complications include thrombosis, hemorrhage, and progression to myelofibrosis or acute myeloid leukemia (AML). Management of essential thrombocythemia/polycythemia vera requires recognition of the risk factors for thrombosis and hemorrhage. Risk stratification allows the clinician to make a treatment plan that may include antiplatelet therapy with aspirin alone or in combination with therapeutic phlebotomy in the case of polycythemia vera, or cytoreductive therapy for high-risk patients with either essential thrombocythemia or polycythemia vera. Hydroxyurea remains first-line therapy for high-risk patients with essential thrombocythemia/polycythemia vera, whereas second-line options include anagrelide, pegylated-IFNα-2a, and the JAK1/2 inhibitor ruxolitinib. The current evaluation of pegylated-IFNα-2a in global phase II and III studies will provide clarity to the potential long-term benefit and risks associated with this biologic in patients with essential thrombocythemia/polycythemia vera. Novel therapeutics aimed at prevention of disease progression to myelofibrosis/AML are the focus of current clinical trials.

Risk stratification of patients with essential thrombocythemia/polycythemia vera by age and/or history of thrombosis provides the basis of risk adapted therapeutic intervention. Aggressive control of modifiable cardiovascular risk factors, the use of antiplatelet agents, control of the hematocrit less than 45% in polycythemia vera, and cytoreductive therapy in high-risk essential thrombocythemia/polycythemia vera patients is the focus of management. The exact role of IFN-α remains undefined and under active investigation, and the recent approval of ruxolitinib provides patients with polycythemia vera a second-line option.