Interferons are cytokines with immunomodulatory properties that have been used in the treatment of myeloproliferative neoplasms (MPNs) for decades. However, their widespread use has been hampered by their adverse effect profile and difficulty with administration. Recently there has been a resurgence of interest in the use of interferons in MPNs given the development of pegylated formulations with improved tolerability. Currently, treatments for polycythemia vera (PV) and essential thrombocythemia (ET) are targeted toward decreasing the risk of thrombotic complications, because there are no approved therapies that are known to modify disease. However, recent data on interferons in MPNs have suggested the potential for disease-modifying activity, including the achievement of molecular remission and sustained clinical response. This development has led to the question of whether interferons should move forward as the preferred frontline cytoreductive agent for ET and PV, and challenges the criteria currently used to initiate therapy. We review randomized controlled trial data evaluating interferon’s efficacy and tolerability in patients with ET and PV. We then consider the data in the context of interferon’s known advantages and disadvantages to address whether interferons should be the first choice for cytoreductive treatment in patients with ET and PV.
Joan How and Gabriela Hobbs
Joan How and Gabriela S. Hobbs
Primary myelofibrosis (PMF) has the least favorable prognosis of the Philadelphia chromosome–negative myeloproliferative neoplasms, which also include essential thrombocythemia (ET) and polycythemia vera (PV). However, clinical presentations and outcomes of PMF vary widely, with median overall survival ranging from years to decades. Given the heterogeneity of PMF, there has been considerable effort to develop discriminatory prognostic models to help with management decisions, particularly for the consideration of hematopoietic stem cell transplantation in patients at higher risk. Although earlier models incorporated only clinical features in risk stratification, contemporary models increasingly use molecular and cytogenetic features, leading to more comprehensive prognostication. This article reviews the most widely adopted prognostic models used for PMF, including the International Prognostic Scoring System (IPSS), dynamic IPSS (DIPSS)/DIPSS+, mutation-enhanced IPSS for transplant-age patients (MIPSS70)/MIPSS70+/MIPSS70+ version 2.0, genetically inspired prognostic scoring system, and Myelofibrosis Secondary to PV and ET-Prognostic Model in patients with post-ET/PV myelofibrosis. We also discuss newly emerging prognostic models and provide a practical approach to risk stratification in patients with PMF and post-ET/PV myelofibrosis.