Letter to Our Readers

Ruben A. Mesa, MD

Dear Colleagues, Polycythemia vera (PV) is a chronic myeloproliferative neoplasm (MPN) that has undergone a major evolution over the past decade. A long-standing and well-recognized disorder of the bone marrow, PV had its watershed moment in 2005, with the discovery of the JAK2 V617F mutation. The identification of this mutation triggered a busy period in terms of improved diagnostic certainty, deeper pathogenetic insights, and the development of more efficacious therapies for persons with PV. The past 10 years have also been a time in which we have achieved a clearer understanding of the symptom burden associated with this disease with respect to morbidity and mortality, and an improved awareness of the complexity involved in managing patients with various MPNs. In an effort to crystallize the evolving and practical application of diagnostic algorithms, prognostication, therapeutic goal setting, and disease management, a multidisciplinary roundtable was convened, which was comprised of physicians from MPN-focused academic centers, community hematologists, outpatient nursing staff, insurance plan administrators, and specialty pharmacists. Topics included a wide range of issues about PV, with the overarching goal being to gain insight and guidance from experts in the field, thus helping to improve outcomes and enhance the quality of life of patients with this disorder. The discussion began with the panelists defining PV in terms of clinical aspects of the disease, symptomatic burden, morbidity and mortality patients might expect, and current diagnostic approaches, as endorsed by the World Health Organization. Further dialogue focused on the phenotypic variation among individuals with PV, the utilization of current mutation testing, and prognostication of patients with the condition. The panel refined the information that has been garnered on the involvement of the Janus kinase (JAK)/Signal Transducer and Activator of Transcription pathway, on how the current mutation profile in PV assists in terms of diagnosis, and on the potential development of novel therapeutic agents. Presentations by the various experts covered management strategies for patients experiencing acute events, goal setting among these patients, prevention of vascular events, and selective use and monitoring of cytoreductive therapies, including hydroxyurea and interferon alfa. A portion of the discussion centered on novel treatments currently under investigation for patients with PV—in particular, selective inhibitors of JAK1/JAK2. Results from the 2014 American Society of Clinical Oncology RESPONSE (Randomized, Open-Label, Multicenter Phase 3 Study of Efficacy and Safety in Polycythemia Vera Subjects Who Are Resistant to or Intolerant of Hydroxyurea: JAK Inhibitor INC424 tablets versus best available care) trial were presented at the meeting. This study compared ruxolitinib treatment with best available therapy (BAT) in approximately 200 patients with advanced PV. According to the RESPONSE trial investigators, in patients with PV who had an inadequate response to, or were intolerant of, hydroxyurea, ruxolitinib was superior to BAT in controlling hematocrit without phlebotomy, normalizing blood cell counts, reducing spleen volume, and improving PV-associated symptoms. The group went on to discuss the potential application of ruxolitinib in clinical practice for patients with PV, based in aggregate on the phenotypic data on the disease presented earlier in the day, as well as on the results of the RESPONSE study. The day concluded with a dialogue on a series of topics that reflected the chain of teamwork involved in the care of patients with PV. Initial discussions highlighted the relationship between MPN-focused academic centers and community hematologists, and how those relationships can work best to manage patients with PV. The conversation then turned to counseling and monitoring patients with PV, including the role played by oncology nurses and nurse navigators. The last portion of the roundtable covered key aspects involved in the support of patients with PV, including the role played by specialty pharmacies, and how health plans approach the assessment and coverage of medical treatments for patients with PV. We hope that the monograph derived from this roundtable discussion will be beneficial to a broad range of individuals involved in the management and care of patients with PV, and will help to elucidate our current understanding of PV diagnosis, treatment goals, and utilization of historical therapies, as well as of such evolving new therapeutic options as JAK inhibition. Sincerely, Ruben A. Mesa, MD, FACP Professor and Chair Division of Hematology and Medical Oncology Deputy Director Mayo Clinic Cancer Center Professor of Medicine Scottsdale, Arizona

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