Emerging drugs for polycythemia vera.

Polycythemia vera (PV) patients suffer from disease-related constitutional symptoms, cardiovascular complications and risk of transformation into myelofibrosis and acute leukemia. Clinical and molecular aspects and current therapies will be described to provide clinical and molecular background to understand the natural history and treatment strategies in PV. Pertinent ongoing research questions, challenges arising out of the specific disease course and biology of PV as well as challenges and opportunities for new agents in PV are addressed. A focus is placed on pegylated interferon-α formulations (PEG-INFa2a) and JAK2 inhibitors. Newest data on symptom burden and incidence and prevalence of PV and MPNs are highlighted in the context of development of PV therapies. Therapeutic goals in PV are to prevent vascular events, reduce symptoms and for future therapies delay/prevent disease progression. Currently available treatments such as phlebotomy, antiplatelet therapy, managing risk factors and cytoreductive therapies such as hydroxyurea (HU) and PEG-INFa2a are effective. JAK2 inhibitors recently have shown promising activity in reducing PV symptoms and spleen size and improving blood counts. Yet the influence of long-term outcome and delaying disease progression is unknown. Thus, there still remains an unmet medical need for improved therapy and symptom management in PV.