The potential role of hematocrit control on symptom burden among polycythemia vera patients: Insights from the CYTO-PV and MPN-SAF patient cohorts

SOHO State of the Art Update and Next Questions: Novel Therapies for Polycythemia Vera

In the recent years, landmark advancements in the treatment of polycythemia vera (PV) have been achieved. We witnessed the regulatory approval of ropeginterferon and the advanced clinical development of other novel agents that may affect the underlying pathophysiological mechanisms of the disease. Agents with the potential of disease modification may soon overtake preceding treatment options that were based on the patient's age and history of thrombosis. Recent studies using ropeginterferon in low-risk PV patients earlier in the disease course challenge the current treatment paradigm and shift the focus on modifying the course of the disease. Hepcidin mimetics offer an excellent alternative to phlebotomy, providing better quality of life, and may lead to improved outcomes in PV by tight hematocrit control. Novel agents, such as histone deacetylase inhibitors, hold promise to complement the therapeutic landscape of PV and might be particularly promising in rationale combinations. Ruxolitinib is well established as an approved second-line treatment for PV. In the frontline setting, the precise role of ruxolitinib, which also represents an appealing agent in combination regimens, will be determined in ongoing research studies. Longer follow-up is necessary to assess whether novel agents/regimens elicit fewer thromboembolic/ hemorrhagic events and halt disease progression to myelofibrosis and acute myeloid leukemia. We aspire that disease-modifying approaches in PV are on the horizon, and that we will be empowered to ultimately change the natural course of the disease and profoundly impact the lives of PV patients in the near future.

The JAK2V617F mutation and the role of therapeutic agents in alleviating myeloproliferative neoplasm symptom burden

Alleviating symptom burden in patients with myeloproliferative neoplasms (MPNs) is imperative to achieving optimal management. Research remains to elucidate the relationship between the JAK2V617F (Janus kinase 2) mutation present in many MPN patients, and the symptomatology they experience. This retrospective study analysed data collected from MPN patients included in the Myeloproliferative Neoplasms: An In-depth Case-Control (MOSAICC) pilot study. The MPN Symptom Assessment Form was administered, and median symptom scores were compared between JAK2V617F-positive and JAK2V617F-negative groups. Multivariate logistic regression analysis adjusted for confounding variables. Overall, 106 MPN patients participated: 65.1% were JAK2V617F positive, 30.2% were JAK2V617F negative and 4.7% had an unknown status. Multivariate analysis revealed a low symptom burden for early satiety (p < 0.01), dizziness (p < 0.05), cough (p < 0.05) and bone pain (p < 0.01) in those receiving venesection alone. Interferon alpha was significantly associated (p < 0.05) with severe burden for 16 of the 27 symptoms. JAK2V617F-positive females experienced a greater symptom burden than JAK2V617F-positive males. There was no discernible relationship between the JAK2V617F mutation and symptom burden in MPN patients, unlike the therapeutic agents investigated. Larger studies are required to validate these results and identify mechanisms of symptom development and control in MPN patients.

Cost-effectiveness of ropeginterferon alfa-2b-njft for the treatment of polycythemia vera

Aim: Patients with polycythemia vera (PV), a rare and chronic blood cancer, are at a higher risk for thromboembolic events, progression to myelofibrosis, and leukemic transformation. In 2021, ropeginterferon alfa-2b-njft (BESREMi®) was approved in the US to treat adults with PV. The purpose of this study is to estimate the cost-effectiveness of ropeginterferon alfa-2b-njft, used as a first- or second-line treatment, for the treatment of patients with PV in the US. Materials & methods: A Markov cohort model was developed from the healthcare system perspective in the United States. Model inputs were informed by the PROUD-PV and CONTINUATION-PV studies and published literature. The model population included both low-risk and high-risk patients with PV. The model compared ropeginterferon alfa-2b-njft used either as first- or second-line versus an alternative treatment pathway of first-line hydroxyurea followed by ruxolitinib. Results: Over the modeled lifetime, ropeginterferon alfa-2b-njft provided an additional 0.4 higher quality-adjusted life years (QALYs) and 0.4 life-years with an added cost of USD60,175, resulting in a cost per QALY of USD141,783. The model was sensitive to treatment costs, the percentage of patients who discontinue hydroxyurea, the percentage of ropeginterferon alfa-2b-njft users who switch to monthly dosing, the percentage of ropeginterferon alfa-2b-njft users as 2nd line treatment, and the treatment response rates. A younger patient age at baseline and a higher percentage of patients with low-risk disease improved the cost-effectiveness of ropeginterferon alfa-2b-njft. Conclusion: Ropeginterferon alfa-2b-njft is a cost-effective treatment option for a broad range of patients with PV, including both low- and high-risk patients and patients with and without prior cytoreductive treatment with hydroxyurea.

Novel therapeutic strategies for essential thrombocythemia/polycythemia vera

Myeloproliferative neoplasms (MPNs) are clonal disorders of hematopoietic stem cells; these include polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). MPNs are inflammatory cancers, wherein the malignant clone generates cytokines that sustain the inflammatory drive in a self-perpetuating vicious cycle. The course of MPNs follows a biological continuum, that is, from early cancer stages (ET/PV) to advanced myelofibrosis as well as impending leukemic transformation. MPN-related symptoms, e.g., fatigue, general weakness, and itching, are caused by inflammatory cytokines. Thrombosis and bleeding are also exacerbated by inflammatory cytokines in patients with MPN. Until recently, the primary objective of ET and PV therapy was to increase survival rates by preventing thrombosis. However, several medications have recently demonstrated the ability to modify the course of the disease; symptom relief is expected for most patients. In addition, there is increasing interest in the active treatment of patients at low risk with PV and ET. This review focuses on the ET/PV treatment strategies as well as novel treatment options for clinical development.

Treatment and Clinical Endpoints in Polycythemia Vera: Seeking the Best Obtainable Version of the Truth

Polycythemia vera (PV) is a Philadelphia chromosome-negative myeloproliferative neoplasm driven by the JAK2 V617F (or rarely exon 12) mutation. Its natural history can extend over a few decades, and therefore treatment planning is predicated on continual re-assessment of traditional risk features (age, prior thrombosis) to evaluate the need for cytoreduction besides foundational therapy with low-dose aspirin and stringent phlebotomy. Shorter- and longer-term patient goals should be considered in light of several variables such as co-morbid conditions (especially cardiovascular risk factors), disease symptoms, and the risk-benefit profile of available drugs. While hydroxyurea has been the pro forma choice of cytoreduction for many practitioners over the last half-century, the more recent regulatory approvals of ruxolitinib and ropeginterferon-alfa-2b, based on phase 3 randomized trials, highlight an expanding portfolio of active drugs. Obtaining high-level evidence for short-term clinical trial endpoints such as hematocrit control, symptom burden/quality of life, splenomegaly, and JAK2 V617F allele burden lies within the timeline of most studies. However, in many cases, it may not be possible to adequately power trials to capture significant differences in the typically low event rates of thrombosis, as well as longer-horizon endpoints such as evolution to myelofibrosis and acute myeloid leukemia, and survival. This Perspective highlights the challenges of addressing these data gaps and outstanding questions in the emerging treatment landscape of PV.

Low-risk polycythemia vera treated with phlebotomies: clinical characteristics, hematologic control and complications in 453 patients from the Spanish Registry of Polycythemia Vera

Hematological control, incidence of complications, and need for cytoreduction were studied in 453 patients with low-risk polycythemia vera (PV) treated with phlebotomies alone. Median hematocrit value decreased from 54% at diagnosis to 45% at 12 months, and adequate hematocrit control over time (< 45%) was observed in 36%, 44%, and 32% of the patients at 6, 12, and 24 months, respectively. More than 5 phlebotomies per year in the maintenance phase were required in 19% of patients. Worsening thrombocytosis, age > 60 years, and microvascular symptoms constituted the main indications for starting cytoreduction. Median duration without initiating cytoreduction was significantly longer in patients younger than 50 years (< 0.0001). The incidence rate of thrombosis under phlebotomies alone was 0.8% per year and the estimated probability of thrombosis at 10 years was 8.5%. The probability of arterial thrombosis was significantly higher in patients with arterial hypertension whereas there was a trend to higher risk of venous thrombosis in cases with high JAK2V617F allele burden. Rates of major bleeding and second primary neoplasm were low. With a median follow-up of 9 years, survival probability at 10 years was 97%, whereas the probability of myelofibrosis at 10 and 20 years was 7% and 20%, respectively. Progression to acute myeloid leukemia was documented in 3 cases (1%). Current management of low-risk PV patients is associated with low rate of thrombosis and long survival. New treatment strategies are needed for improving hematological control and, in the long term, reducing progression to myelofibrosis.

Management Issues and Controversies in Low-Risk Patients with Essential Thrombocythemia and Polycythemia Vera

PURPOSE OF REVIEW

Essential thrombocythemia (ET) and polycythemia vera (PV) are the most common myeloproliferative neoplasms (MPNs). Treatment of ET and PV is based on the risk for subsequent thrombosis. High-risk patients, defined as older than 60, JAK2 V617F-positive patients, or patients with a history of prior thrombosis, merit cytoreduction to control blood counts, whereas a watchful waiting paradigm is utilized in low-risk patients. However, low-risk patients have a host of other specific management issues that arise during their disease course. This review will discuss the most common management issues specific to the care of low-risk patients, including anti-platelet therapy dosing, pregnancy, and indications for early cytoreduction.

RECENT FINDINGS

Although low-dose aspirin is well established in PV, its indications and dosing regimens are less clear in ET. Recent evidence has supported twice daily low-dose aspirin in ET and observation alone in very low-risk ET patients. Pregnancy is not contraindicated in MPNs, and we recommend aspirin throughout pregnancy with consideration for prophylactic postpartum anticoagulation. High phlebotomy needs, symptom burden, and extreme thrombocytosis are common reasons for initiation of cytoreduction in low-risk patients, although we typically do not start cytoreduction for an isolated high platelet count alone. Recent data has also demonstrated a potential disease-modifying effect of interferons in MPNs, with some experts now advocating the early use of interferon in low-risk patients, although more mature data is needed before practice guidelines change. We evaluate the literature to inform clinical decision-making regarding these controversies, including most recent data that has challenged the "watchful waiting" paradigm. Our discussion provides guidance on common clinical scenarios seen in low-risk ET and PV patients, who face a myriad of complex management decisions in their care.

Recent advances in prognostication and treatment of polycythemia vera

Polycythemia vera (PV) is a BCR-ABL–negative myeloproliferative neoplasm marked by acquisition of an activating mutation of JAK2, which leads to not only erythrocytosis but also frequently to leukocytosis and thrombocytosis, and is associated with a high symptom burden and increased thrombotic risk. PV has the potential to progress to myelofibrosis or an aggressive form of acute myeloid leukemia. Mutational profiling of patients with PV has led to the development of risk stratification tools to determine an individual’s risk of developing progressive disease. Although the current goals of PV treatment are to alleviate symptoms and reduce thrombotic risk, there are growing efforts to identify disease-modifying agents which will also prevent progression of disease. Here, we give an overview of the developing prognostic tools and therapeutic landscape for PV, focusing on four drug classes: pegylated interferon-alpha 2, MDM2 antagonists, hepcidin mimetics, and histone deacetylase inhibitors.

Quality of Life in Myeloproliferative Neoplasms: Symptoms and Management Implications

Myeloproliferative neoplasms include essential thrombocythemia, polycythemia vera, and myelofibrosis. They are characterized by abnormal myeloid proliferation. Patients suffer from debilitating constitutional symptoms and splenomegaly. There have been advances in understanding the impact on quality of life in myeloproliferative neoplasms. Owing to the chronicity of these diseases, symptoms are considered in response criteria for clinical trials. This review wills cover how quality of life is measured in patients with myeloproliferative neoplasm. We review the impact of treatment options, including JAK inhibitors, allogeneic stem cell transplantation, and medications in development. We discuss nonpharmacologic methods of improving symptoms and quality of life.

Ropeginterferon alfa-2b versus phlebotomy in low-risk patients with polycythaemia vera (Low-PV study): a multicentre, randomised phase 2 trial

BACKGROUND

There is no evidence that phlebotomy alone is sufficient to steadily maintain haematocrit on target level in low-risk patients with polycythaemia vera. This study aimed to compare the efficacy and safety of ropeginterferon alfa-2b on top of the standard phlebotomy regimen with phlebotomy alone.

METHODS

In 2017, we launched the Low-PV study, a multicentre, open-label, two-arm, parallel-group, investigator-initiated, phase 2 randomised trial with a group-sequential adaptive design. The study involved 21 haematological centres across Italy. Participants were recruited in a consecutive order. Participants enrolled in the study were patients, aged 18-60 years, with a diagnosis of polycythaemia vera according to 2008-16 WHO criteria. Eligible patients were randomly allocated (1:1) to receive either phlebotomy and low-dose aspirin (standard group) or ropeginterferon alfa-2b on top of the standard treatment (experimental group). Randomisation sequence was generated using five blocks of variable sizes proportional to elements of Pascal's triangle. Allocation was stratified by age and time from diagnosis. No masking was done. Patients randomly allocated to the standard group were treated with phlebotomy (300 mL for each phlebotomy to maintain the haematocrit values of lower than 45%) and low-dose aspirin (100 mg daily), if not contraindicated. Patients randomly allocated to the experimental group received ropeginterferon alfa-2b subcutaneously every 2 weeks in a fixed dose of 100 μg on top of the phlebotomy-only regimen. The primary endpoint was treatment response, defined as maintenance of the median haematocrit values of 45% or lower without progressive disease during a 12-month period. Analyses were done by intention-to-treat principle. The study was powered assuming a higher percentage of responders in the experimental group (75%) than in the standard group (50%). Here we report results from the second planned interim analysis when 50 patients had been recruited to each group. The trial is ongoing, and registered with ClinicalTrials.gov, NCT03003325.

FINDINGS

Between Feb 2, 2017, and March 13, 2020, 146 patients were screened, and 127 patients were randomly assigned to the standard group (n=63) or the experimental group (n=64). The median follow-up period was 12·1 months (IQR 12·0-12·6). For the second pre-planned interim analysis, a higher response rate in the experimental group was seen (42 [84%] of 50 patients) than in the standard group (30 [60%] of 50 patients; absolute difference 24%, 95% CI 7-41%, p=0·0075). The observed z value (2·6001) crossed the critical bound of efficacy (2·5262), and the stagewise adjusted p value early showed superiority of experimental treatment. Thus, the data safety monitoring board decided to stop patient accrual for overwhelming efficacy and to continue the follow-up, as per protocol, for 2 years. Under the safety profile, no statistically significant difference between groups in frequency of adverse events of grade 3 or higher was observed; the most frequently reported adverse events were neutropenia (four [8%] of 50 patients) in the experimental group and skin symptoms (two [4%] of 50 patients) in the standard group. No grade 4 or 5 adverse events occurred.

INTERPRETATION

Supplementing phlebotomy with ropeginterferon alfa-2b seems to be safe and effective in steadily maintaining haematocrit values on target in low-risk patients with polycythaemia vera. Findings from the current study might have implications for changing the current management of low-risk patients with polycythaemia vera.

FUNDING

AOP Orphan Pharmaceuticals, Associazione Italiana per la Ricerca sul Cancro.

Health-Related Quality of Life in Patients with Philadelphia-Negative Myeloproliferative Neoplasms: A Nationwide Population-Based Survey in Denmark

Simple Summary

The aim of this research was to investigate the health-related quality of life (HRQoL) in patients with Philadelphia-negative myeloproliferative neoplasms (chronic blood cancers) in Denmark. A nationwide questionnaire survey covering functioning, symptom burden, symptom profile, QoL, and lifestyle was performed. Patients registered in the National Patient Register with a diagnosis of Philadelphia-negative myeloproliferative neoplasm were invited. A total of 2228 patients participated in the survey and these could be divided into groups of participants with different subtypes of Phildelphia-negative myeloproliferative neoplasms. The HRQoL across groups of participants with different subtypes of the disease was compared, and the HRQoL of all participants and the general population was compared in order to investigate for a potential difference. The participants reported their HRQoL to be inferior to the general population, but the difference was minor. The differences in HRQoL across groups of participants with different subtypes of the disease were subtle. Fatigue and sexual problems were prevalent and burdensome. Participants reported a slightly healthier lifestyle than the general population. Understanding HRQoL of these patients is a necessity to be able to provide the best treatment and rehabilitation activities.

Abstract

Previous studies have clarified that many patients with Philadelphia-negative myeloproliferative neoplasms (MPNs) have burdensome symptom profiles and accordingly impaired functioning and quality of life (QoL). In Denmark, all MPN patients are affiliated with public hospitals and because of a healthcare system financed by taxpayers these patients do not have any financial costs related to the hematological disease. Diagnoses are recorded for all patients in hospitals, and diagnosis codes are communicated to the National Patient Register (NPR). Owing to this, it was possible to contribute to the elucidation of Philadelphia-negative MPN patients’ health-related quality of life (HRQoL), by conducting a nationwide, population-based, cross-sectional HRQoL survey of these patients with cost-free access to the best available, suitable medical treatment. The survey contained validated questionnaires covering functioning, symptom burden, symptom profile, QoL, and additional questions on lifestyle. Information on comorbid diagnoses was obtained from the NPR. The participants’ HRQoL was compared to the general population. Moreover, differences in HRQoL across essential thrombocythemia, polycythemia vera, myelofibrosis, and unclassifiable MPN participants were investigated, adjusted for age, sex, comorbidity, and lifestyle. To the best of our knowledge this is the first survey of HRQoL in patients with unclassifiable MPN. A total of 2228 Philadelphia-negative MPN patients participated. The participants reported their HRQoL to be inferior to the general population, but the difference was minor. The differences in HRQoL across groups of participants with different MPN subtypes were subtle. Fatigue and sexual problems were prevalent and burdensome. Overall, participants reported a slightly healthier lifestyle compared to the general population.

Long-term efficacy and safety of ruxolitinib versus best available therapy in polycythaemia vera (RESPONSE): 5-year follow up of a phase 3 study

BACKGROUND

Polycythaemia vera is a myeloproliferative neoplasm characterised by excessive proliferation of erythroid, myeloid, and megakaryocytic components in the bone marrow due to mutations in the Janus kinase 2 (JAK2) gene. Ruxolitinib, a JAK 1 and JAK 2 inhibitor, showed superiority over best available therapy in a phase 2 study in patients with polycythaemia vera who were resistant to or intolerant of hydroxyurea. We aimed to compare the long-term safety and efficacy of ruxolitinib with best available therapy in patients with polycythaemia vera who were resistant to or intolerant of hydroxyurea.

METHODS

We report the 5-year results for a randomised, open-label, phase 3 study (RESPONSE) that enrolled patients at 109 sites across North America, South America, Europe, and the Asia-Pacific region. Patients (18 years or older) with polycythaemia vera who were resistant to or intolerant of hydroxyurea were randomly assigned 1:1 to receive either ruxolitinib or best available therapy. Patients randomly assigned to the ruxolitinib group received the drug orally at a starting dose of 10 mg twice a day. Single-agent best available therapy comprised hydroxyurea, interferon or pegylated interferon, pipobroman, anagrelide, approved immunomodulators, or observation without pharmacological treatment. The primary endpoint, composite response (patients who achieved both haematocrit control without phlebotomy and 35% or more reduction from baseline in spleen volume) at 32 weeeks was previously reported. Patients receiving best available therapy could cross over to ruxolitinib after week 32. We assessed the durability of primary composite response, complete haematological remission, overall clinicohaematological response, overall survival, patient-reported outcomes, and safety after 5-years of follow-up. This study is registered with ClinicalTrials.gov, NCT01243944.

FINDINGS

We enrolled patients between Oct 27, 2010, and Feb 13, 2013, and the study concluded on Feb 9, 2018. Of 342 individuals screened for eligibility, 222 patients were randomly assigned to receive ruxolitinib (n=110, 50%) or best available therapy (n=112, 50%). The median time since polycythaemia vera diagnosis was 8·2 years (IQR 3·9-12·3) in the ruxolitinib group and 9·3 years (4·9-13·8) in the best available therapy group. 98 (88%) of 112 patients initially randomly assigned to best available therapy crossed over to receive ruxolitinib and no patient remained on best available therapy after 80 weeks of study. Among 25 primary responders in the ruxolitinib group, six had progressed at the time of final analysis. At 5 years, the probability of maintaining primary composite response was 74% (95% CI 51-88). The probability of maintaining complete haematological remission was 55% (95% CI 32-73) and the probability of maintaining overall clinicohaematological responses was 67% (54-77). In the intention-to-treat analysis not accounting for crossover, the probability of survival at 5 years was 91·9% (84·4-95·9) with ruxolitinib therapy and 91·0% (82·8-95·4) with best available therapy. Anaemia was the most common adverse event in patients receiving ruxolitinib (rates per 100 patient-years of exposure were 8·9 for ruxolitinib and 8·8 for the crossover population), though most anaemia events were mild to moderate in severity (grade 1 or 2 anaemia rates per 100 patient-years of exposure were 8·0 for ruxolitinib and 8·2 for the crossover population). Non-haematological adverse events were generally lower with long-term ruxolitinib treatment than with best available therapy. Thromboembolic events were lower in the ruxolitinib group than the best available therapy group. There were two on-treatment deaths in the ruxolitinib group. One of these deaths was due to gastric adenocarcinoma, which was assessed by the investigator as related to ruxolitinib treatment.

INTERPRETATION

We showed that ruxolitinib is a safe and effective long-term treatment option for patients with polycythaemia vera who are resistant to or intolerant of hydroxyurea. Taken together, ruxolitinib treatment offers the first widely approved therapeutic alternative for this post-hydroxyurea patient population.

FUNDING

Novartis Pharmaceuticals Corporation.

Dysregulated iron metabolism in polycythemia vera: etiology and consequences

Polycythemia vera (PV) is a chronic myeloproliferative neoplasm. Virtually all PV patients are iron deficient at presentation and/or during the course of their disease. The co-existence of iron deficiency and polycythemia presents a physiological disconnect. Hepcidin, the master regulator of iron metabolism, is regulated by circulating iron levels, erythroblast secretion of erythroferrone, and inflammation. Both decreased circulating iron and increased erythroferrone levels, which occur as a consequence of erythroid hyperplasia in PV, are anticipated to suppress hepcidin and enable recovery from iron deficiency. Inflammation which accompanies PV is likely to counteract hepcidin suppression, but the relatively low serum ferritin levels observed suggest that inflammation is not a major contributor to the dysregulated iron metabolism. Furthermore, potential defects in iron absorption, aberrant hypoxia sensing and signaling, and frequency of bleeding to account for iron deficiency in PV patients have not been fully elucidated. Insufficiently suppressed hepcidin given the degree of iron deficiency in PV patients strongly suggests that disordered iron metabolism is an important component of the pathobiology of PV. Normalization of hematocrit levels using therapeutic phlebotomy is the most common approach for reducing the incidence of thrombotic complications, a therapy which exacerbates iron deficiency, contributing to a variety of non-hematological symptoms. The use of cytoreductive therapy in high-risk PV patients frequently works more effectively to reverse PV-associated symptoms in iron-deficient relative to iron-replete patients. Lastly, differences in iron-related parameters between PV patients and mice with JAK2 V617F and JAK2 exon 12 mutations suggest that specific regions in JAK2 may influence iron metabolism by nuanced changes of erythropoietin receptor signaling. In this review, we comprehensively discuss the clinical consequences of iron deficiency in PV, provide a framework for understanding the potential dysregulation of iron metabolism, and present a rationale for additional therapeutic options for iron-deficient PV patients.

Ruxolitinib for the treatment of inadequately controlled polycythemia vera without splenomegaly: 80-week follow-up from the RESPONSE-2 trial

RESPONSE-2 is a phase 3 study comparing the efficacy and safety of ruxolitinib with the best available therapy (BAT) in hydroxyurea-resistant/hydroxyurea-intolerant polycythemia vera (PV) patients without palpable splenomegaly. This analysis evaluated the durability of the efficacy and safety of ruxolitinib after patients completed the visit at week 80 or discontinued the study. Endpoints included proportion of patients achieving hematocrit control (< 45%), proportion of patients achieving complete hematologic remission (CHR) at week 28, and the durability of hematocrit control and CHR. At the time of analysis, 93% (69/74) of patients randomized to ruxolitinib were receiving ruxolitinib; while in the BAT arm, 77% (58/75) of patients crossed over to ruxolitinib after week 28. No patient remained on BAT by week 80. Among patients who achieved a hematocrit response at week 28, the probability of maintaining response up to week 80 was 78% in the ruxolitinib arm. At week 80, durable CHR was achieved in 18 patients (24%) in the ruxolitinib arm versus 2 patients (3%) in the BAT arm. The safety profile of ruxolitinib was consistent with previous reports. These data support that ruxolitinib treatment should be considered also as a standard of care for hydroxyurea-resistant/hydroxyurea-intolerant PV patients without palpable splenomegaly.

Current approaches to challenging scenarios in myeloproliferative neoplasms

INTRODUCTION

The Philadelphia chromosome-negative myeloproliferative neoplasms (MPNs) including polycythemia vera, essential thrombocythemia and primary myelofibrosis are clonal hematological malignancies that originate at the level of the hematopoietic stem cell, and are characterized by excessive proliferation of cells belonging to one or more of the myeloid lineages. Central to the pathogenesis of the MPNs is constitutive activation of the JAK/STAT signaling pathway due to a family of driver mutations affecting JAK2, CALR or MPL. These disorders share common clinical and laboratory features, a significant burden of systemic symptoms, increased risk of developing arterial and venous thrombotic events, and the potential to progress to myelofibrosis and acute leukemia. Areas covered: We identified four clinical situations which represent challenging management dilemmas for patients with MPNs. Our conclusions and recommendations are based on a literature search using MEDLINE and recent meeting abstracts using the keywords, focusing on publications directly addressing these scenarios and on recent contributions to the field. Expert commentary: Multi-center efforts to study large cohorts of MPN patients have led to more uniform and evidence-based approaches to key aspects in MPN management. However, treatment strategies to deal with specific clinical scenarios are lacking.

Myeloproliferative Neoplasms: Translating New Discoveries Into Better Outcomes, Better Quality of Life

Despite the identification of JAK mutations and the development of targeted inhibitors, there remain significant unmet needs for patients with myeloproliferative neoplasms. Identification of the myeloproliferative neoplasm populations not currently benefiting from JAK inhibitor therapy highlights the therapeutic deficits still present in this heterogeneous stem cell malignancy. While JAK inhibition has provided significant benefits for patients with intermediate-2 or high-risk myelofibrosis and in patients with polycythemia vera in the second-line setting, JAK inhibitor monotherapy is not approved and not appropriate for all patients with myeloproliferative neoplasms. Continued investigation into additional JAK inhibitors, combination therapy, and novel pathway therapeutics remains key to improving outcomes for all patients with myeloproliferative neoplasms. While therapeutic advances in the JAK inhibitor arena or involving alternative pathways are crucial to improving outcomes in myeloproliferative neoplasms, it is also important to reconsider the role of constitutional symptoms in affected patients as an indication for treatment with agents, such as JAK inhibitors, that can mitigate these debilitating symptoms. In this review, we demonstrate the evolving landscape of clinical investigations that address the important therapeutic needs of patients with myeloproliferative neoplasms.