Novel agents for the treatment of polycythemia vera: an insight into preclinical research and early phase clinical trials.

INTRODUCTION: Current treatment for polycythemia vera (PV) is limited and primarily targets thrombosis risk. Agents targeting distinct mechanisms of action within myeloproliferation are undergoing clinical evaluation to optimize efficacy, improve tolerance and augment long term disease complications. AREA COVERED: This article reviews the current data from completed early phase clinical trials in PV, either as monotherapy or in combination with the few currently approved agents. EXPERT OPINION: There remains an opportunity in PV management to improve efficacy and decrease risk of disease progression. Evolving data from use of long acting interferons are serving to clarifying the potential front line role of this therapy. JAK2 inhibition has made a significant impact on decreasing morbidity in patients with hydroxyurea resistant/refractory disease. New approaches may soon expand options including histone deactylase inhibitors (HDACi), either as monotherapy or combination therapy, which showed promising activity and symptomatic control of pruritus. Drugs targeting new molecular pathways (mammalian target of rapamycin, insulin receptor substrates 1/2, MDM2 protein) or the iron metabolism pathway are in early phase trial. Further translational studies assessing efficacy, long term complications, survival, and constitutional symptom control could pave a way for future success in PV drug development either as monotherapy or in combination.