The unprecedented success of ruxolitinib in myelofibrosis (MF) has paved the way for the development of other Janus kinase (JAK) inhibitors and other agents representing diverse drug classes and mechanisms of action in myeloproliferative neoplasms (MPNs). In particular, the symptomatic benefits afforded by ruxolitinib have led to the recognition of “clinical improvement” in symptoms and the spleen in international consensus response criteria for MF. Ruxolitinib is also approved for the second-line treatment of polycythemia vera and is being developed for essential thrombocythemia. Appreciation of the universal role of activated JAK/signal transducer and activator of transcription (STAT) signaling in MPNs and improved understanding of the canonical and noncanonical actions of JAK2 have yielded a number of drug targets beyond JAK2 in MPNs, which form the basis for a number of ruxolitinib-based rational combinations that are being explored in MF. Other JAK inhibitors with the potential for significantly less myelosuppression or even improvement of anemia continue to be tested. Finally, agents with very distinct mechanisms of action, such as novel interferon formulations, antifibrotic agents, and telomerase inhibitors, are being pursued in polycythemia vera and MF, respectively. This article reviews the current landscape of clinical drug development in MPNs, focusing on the most promising agents and combinations.
Prithviraj Bose and Srdan Verstovsek
Juliana E. Hidalgo-López, Rashmi Kanagal-Shamanna, L. Jeffrey Medeiros, Zeev Estrov, C. Cameron Yin, Srdan Verstovsek, Sergej Konoplev, Jeffrey L. Jorgensen, Mohammad M. Mohammad, Roberto N. Miranda, Chong Zhao, John Lee, Zhuang Zuo, and Carlos E. Bueso-Ramos
Background: JAK2 V617F mutation (mut) in acute myeloid leukemia (AML) is rare. We describe the clinicopathologic findings of a single-institution series of 11 de novo AML cases with JAK2 V617. Methods: We identified cases of de novo AML with JAK2 V617F over a 10-year period. We reviewed diagnostic peripheral blood and bone marrow (BM) morphologic, cytogenetic, and molecular studies, including next-generation sequencing. The control group consisted of 12 patients with JAK2 wild-type (wt) AML matched for age, sex, and diagnosis. Results: We identified 11 patients (0.5%) with JAK2 V617F, with a median age at diagnosis of 72.5 years (range, 36–90 years). Ten neoplasms were classified as AML with myelodysplasia-related changes and 1 as AML with t(8;21)(q22;q22). All JAK2mut AML cases showed at least bilineage dysplasia, 7 of 11 showed fibrosis, 8 of 11 had an abnormal karyotype, and 5 had deletions or monosomy of chromosomes 5 and 7. Using the European LeukemiaNet (ELN) classification, 9 patients (82%) with JAK2mut AML were intermediate-2 and adverse risk. Cases of JAK2mut AML did not have mutations in other activating signaling pathways (P=.013); 7 (64%) showed additional mutations in at least one gene involving DNA methylation and/or epigenetic modification. Patients with JAK2mut AML had a significantly higher median BM granulocyte percentage (12% vs 3.5%; P=.006) and a higher frequency of ELN intermediate-2 and adverse risk cytogenetics (P=.04) compared with those with JAK2wt AML. JAK2mut AML showed higher circulating blasts, but this difference was not significant (17% vs 5.5%; P=not significant). No difference was seen in the median overall survival rate of patients with JAK2mut AML versus those with JAK2wt AML (14 vs 13.5 months, respectively). Conclusions: De novo JAK2mut AML is rare and frequently found in patients with dysplasia, BM fibrosis, and abnormal karyotype with intermediate- or high-risk features; gene mutations in DNA methylation and epigenetic-modifying pathways; and absence of gene mutations in activating signaling pathways.
Ruben Mesa, Catriona Jamieson, Ravi Bhatia, Michael W. Deininger, Aaron T. Gerds, Ivana Gojo, Jason Gotlib, Krishna Gundabolu, Gabriela Hobbs, Rebecca B. Klisovic, Patricia Kropf, Sanjay R. Mohan, Stephen Oh, Eric Padron, Nikolai Podoltsev, Daniel A. Pollyea, Raajit Rampal, Lindsay A. M. Rein, Bart Scott, David S. Snyder, Brady L. Stein, Srdan Verstovsek, Martha Wadleigh, Eunice S. Wang, Mary Anne Bergman, Kristina M. Gregory, and Hema Sundar
Myelofibrosis (MF), polycythemia vera (PV), and essential thrombocythemia (ET) are a group of heterogeneous disorders of the hematopoietic system collectively known as Philadelphia chromosome–negative myeloproliferative neoplasms (MPNs). The diagnosis and the management of patients with MPNs have evolved since the identification of mutations that activate the JAK pathway (JAK2, CALR, and MPL mutations) and the development of targeted therapies has resulted in significant improvements in disease-related symptoms and quality of life. This manuscript discusses the recommendations outlined in the NCCN Guidelines for the diagnostic workup of MPN (MF, PV, and ET), risk stratification, treatment, and supportive care strategies for the management of MF.
Brady L. Stein, Jason Gotlib, Murat Arcasoy, Marie Huong Nguyen, Neil Shah, Alison Moliterno, Catriona Jamieson, Daniel A. Pollyea, Bart Scott, Martha Wadleigh, Ross Levine, Rami Komrokji, Rebecca Klisovic, Krishna Gundabolu, Patricia Kropf, Meir Wetzler, Stephen T. Oh, Raul Ribeiro, Rita Paschal, Sanjay Mohan, Nikolai Podoltsev, Josef Prchal, Moshe Talpaz, David Snyder, Srdan Verstovsek, and Ruben A. Mesa
The classical Philadelphia chromosome–negative myeloproliferative neoplasms (MPN), which include essential thrombocythemia, polycythemia vera, and myelofibrosis (MF), are in a new era of molecular diagnosis, ushered in by the identification of the JAK2 V617F and cMPL mutations in 2005 and 2006, respectively, and the CALR mutations in 2013. Coupled with increased knowledge of disease pathogenesis and refined diagnostic criteria and prognostic scoring systems, a more nuanced appreciation has emerged of the burden of MPN in the United States, including the prevalence, symptom burden, and impact on quality of life. Biological advances in MPN have translated into the rapid development of novel therapeutics, culminating in the approval of the first treatment for MF, the JAK1/JAK2 inhibitor ruxolitinib. However, certain practical aspects of care, such as those regarding diagnosis, prevention of vascular events, choice of cytoreductive agent, and planning for therapies, present challenges for hematologists/oncologists, and are discussed in this article.
Ruben A. Mesa, Catriona Jamieson, Ravi Bhatia, Michael W. Deininger, Christopher D. Fletcher, Aaron T. Gerds, Ivana Gojo, Jason Gotlib, Krishna Gundabolu, Gabriela Hobbs, Brandon McMahon, Sanjay R. Mohan, Stephen Oh, Eric Padron, Nikolaos Papadantonakis, Philip Pancari, Nikolai Podoltsev, Raajit Rampal, Erik Ranheim, Vishnu Reddy, Lindsay A.M. Rein, Bart Scott, David S. Snyder, Brady L. Stein, Moshe Talpaz, Srdan Verstovsek, Martha Wadleigh, Eunice S. Wang, Mary Anne Bergman, Kristina M. Gregory, and Hema Sundar
Myeloproliferative neoplasms (MPNs) are a group of heterogeneous disorders of the hematopoietic system that include myelofibrosis (MF), polycythemia vera (PV), and essential thrombocythemia (ET). PV and ET are characterized by significant thrombohemorrhagic complications and a high risk of transformation to MF and acute myeloid leukemia. The diagnosis and management of PV and ET has evolved since the identification of mutations implicated in their pathogenesis. These NCCN Guideline Insights discuss the recommendations outlined in the NCCN Guidelines for the risk stratification, treatment, and special considerations for the management of PV and ET.