Polycythemia vera and essential thrombocythemia: 2013 update on diagnosis, risk-stratification, and management

Prediction of acute coronary syndrome in patients with myeloproliferative neoplasms

Background

Patients with myeloproliferative neoplasms (MPN) are exposed to a higher risk of cardiovascular disease, especially cardiovascular calcification. The present research aimed to analyze the clinical features and coronary artery calcium score (CACS) in MPN patients, and construct an effective model to predict acute coronary syndrome (ACS) in MPN patients.

Materials and methods

A total of 175 MPN patients and 175 controls were recruited from the First Affiliated Hospital of Ningbo University. Based on cardiovascular events, the MPN patients were divided into the ACS group and the non-ACS group. Multivariate Cox analysis was completed to explore ACS-related factors. Furthermore, ROC curves were plotted to assess the predictive effect of CACS combined with white blood cells (WBC) and platelet for ACS in MPN patients.

Results

The MPN group exhibited a higher CACS than the control group (133 vs. 55, P < 0.001). A total of 16 patients developed ACS in 175 MPN patients. Compared with non-ACS groups, significant differences in age, diabetes, smoking history, WBC, percentage of neutrophil, percentage of lymphocyte, neutrophil count, hemoglobin, hematocrit, platelet, lactate dehydrogenase, β 2-microglobulin, and JAK2V617F mutation were observed in the ACS groups. In addition, the CACS in the ACS group was also significantly higher than that in the non-ACS group (374.5 vs. 121, P < 0.001). The multivariable Cox regression analysis identified WBC, platelet, and CACS as independent risk factors for ACS in MPN patients. Finally, ROC curves indicated that WBC, platelet, and CACS have a high predictive value for ACS in MPN patients (AUC = 0.890).

Conclusion

CACS combined with WBC and platelet might be a promising model for predicting ACS occurrence in MPN patients.

Evaluation of different diagnostic tools for detection of acquired von Willebrand syndrome in patients with polycythemia vera or essential thrombocythemia

INTRODUCTION

Patients with myeloproliferative neoplasms (MPNs) are at increased risk of both thromboembolic and hemorrhagic complications. Among the risk factors for bleeding is the development of an acquired qualitative von Willebrand factor defect with loss of larger VWF plasma multimers, resulting in acquired von Willebrand syndrome (aVWS). The diagnosis of aVWS is challenging, because no single automated test is sufficient to prove or exclude aVWS. We aimed to compare different diagnostic tools used for the detection of MPN-associated aVWS in daily practice.

METHODS

Patients with polycythemia vera (PV) or essential thrombocythemia (ET), who had been routinely assessed for quantitative and qualitative abnormalities of plasma VWF, were retrospectively studied.

RESULTS

Sixty-four patients (37 with PV and 27 with ET) were analyzed. Using multimer analysis of plasma VWF, aVWS with a loss of VWF high-molecular-weight multimers was detected in 51.4 % and 55.6 % of PV and ET patients, respectively.

A VWF

GPIbM/Ag threshold of <0.8 was defined as useful screening tool for aVWS, with acceptable sensitivity (88.2 %) and specificity (76.7 %) and good agreement with VWF multimer analysis (κ = 0.653). VWF:GPIbM/Ag showed better performance than VWF:CB/Ag. Regarding hematological parameters, there was no difference in hematocrit between patients with and without aVWS. However, leukocyte and platelet counts were significantly increased in the aVWS cohort.

CONCLUSION

For the first time, we identified a VWF:GPIbM/Ag ratio of <0.8 as simple screening tool for aVWS in patients with PV or ET. This observation, however, should be confirmed in a larger patient cohort.

Lights Off, Lights On: Amaurosis Fugax in Polycythemia

There are many causes of amaurosis fugax, including polycythemia. Polycythemia is associated with elevated hematocrit levels and hyperviscosity, which can lead to ocular manifestations. We report a polycythemia patient with amaurosis fugax, who had resolution of ocular symptoms following venesection. A 29-year-old gentleman presented with a six-month history of episodic bilateral transient loss of vision (amaurosis fugax), followed by slow recovery back to normal after 15-20 minutes. The symptoms worsened with fatigue. He also had an unsteady gait for the preceding one year. Ocular examination was unremarkable. His visual acuity was 20/20 OU. Neurological examination revealed gait ataxia and dysdiadochokinesia. Computed tomography (CT) angiogram showed an old cerebellar infarct. Blood investigations showed persistent elevated hemoglobin and hematocrit with positive JAK-2 V617F mutation. Infective and connective tissue workups were all negative. A diagnosis of polycythemia was made by the haematology team. In addition to oral aspirin given by the neurology team, he underwent venesection with improvement in ocular symptoms following each episode of venesection. The frequency of amaurosis fugax reduced from 2-3 episodes a week to once a month, then resolved completely after five venesections. Systemically, his cerebellar symptoms also resolved and there were no neurological deficits. Polycythemia is a rare disease that can cause amaurosis fugax and thrombotic events in young patients. Better knowledge and accurate diagnosis are important, as early treatment may improve the symptoms and long-term morbidity.

Case Report: Free-Floating Intracoronary Thrombus: Who Is the Convict?

In young patients, especially with no traditional coronary risk factors, hypercoagulable states may always be considered as an alternative cause of acute coronary syndromes. The concomitant thrombotic and bleeding risk associated with myeloproliferative disorders complicates the decision-making, particularly regarding long-term dual antiplatelet therapy. The chosen therapy may need to be frequently revisited, depending on the patient's bleeding complications. We reported the case of a 49-year-old woman with acute myocardial infarction with no traditional risk factors for coronary artery disease where a myeloproliferative neoplasm was diagnosed.

Cytoreductive treatment in real life: a chart review analysis on 1440 patients with polycythemia vera

Purpose

Patients with polycythemia vera (PV) show an elevated incidence of thromboembolic complications and decreased survival when compared to age-matched healthy individuals. Hypercellularity as indicated by elevated hematocrit, pathophysiological changes induced by the JAK2 driver mutation and cardiovascular risk factors contribute to the increased incidence of thromboembolic events. Higher age and a history of thromboembolic events define a high-risk population of PV patients. Depending on the individual risk profile, phlebotomy or pharmacologic cytoreduction is recommended in combination with low-dose acetylsalicylic acid. Stringent cytoreduction is required for effective risk reduction. However, in recent reports, the rate of thromboembolic complications in PV patients under cytoreductive therapy appears still elevated compared to healthy individuals. This study reports on a chart review to assess for cytoreductive therapy of 1440 PV patients in real life.

Methods

Forty-two eligible hematologists/oncologists in private practice treating patients with MPN were recruited to participate in a paper–pencil-based survey conducted between January 2019 and March 2020 in Germany. Physicians were asked to report primary documented data obtained from patient charts. Descriptive analyses were conducted to assess for patient characteristics, treatment modalities, risk factors and thromboembolic complications.

Results

Data were collected from the patient charts of 1440 individuals diagnosed with PV. The patient population was older than those reported in multicenter trials with a median age of 72.2 years at the time of reporting and 63.5 years at diagnosis. Age was the main factor accounting for high-risk status with 84.7% of patients being above the age of 60 followed by thromboembolic complications reported in 21.3% of patients. The use of pharmacologic cytoreduction was highly variable between participating centers with an average of 60.7% and a range of 10.1–100%. Hydroxyurea was the most frequently used drug followed by ruxolitinib, while interferons were reported for a minority of patients. For 35.4% of patients a persistent need for phlebotomy in addition to cytoreductive treatment was reported. Although presence of high-risk criteria and insufficient disease control were reported as main triggers to initiate pharmacologic cytoreduction, 28.1% had elevated hematocrit values (> 45%) and 38.6% showed persistence of elevated leukocyte count (> 10^9/l) while on cytoreductive treatment. In contrast, physician-reported symptom burden was lower than published in clinical trials and patient-reported outcomes. The rate of patients experiencing thromboembolic complications was 32.2% at any time and 14.3% after diagnosis with most patients receiving acetylsalicylic acid and 10.8% remaining on oral anticoagulants or heparin.

Conclusions

Cytoreductive treatment of high-risk PV in real life is highly variable regarding indication for cytoreduction and definition of therapy resistance. This study highlights the need for (i) improved risk stratification for thromboembolic events, (ii) consequent indication of pharmacologic cytoreduction in high-risk PV and (iii) attention to signs of therapy resistance that can trigger an earlier and stringent switch to second line agents.

Concomitant Essential Thrombocythemia and Mature B -Lymphoproliferative Disorder in a Patient

A-64-year old male presented with cough, weight loss, and maculopapular rash for 15-20 days. On examination, he was found to have cervical lymphadenopathy and splenomegaly. His leukocyte count was 62.1x10⁹/L, platelets were 1169x10⁹/L and LDH was 816 IU/L. Peripheral blood film showed a leukoerythroblastic picture with thrombocytosis. He was started on hydroxyurea and allopurinol. Subsequently, bone marrow evaluation was done which depicted increased lymphoid cells with an M:E ratio of 4:1. Cellular areas exhibited an increase in myeloid precursors along with prominent lymphoid cells and abundant megakaryocytes. Immunohistochemistry showed an increase in B-lymphocytes. Grade MF-2 reticulin fibrosis was noted. Overall findings suggested essential thrombocythemia (ET). On flow cytometry, CD45-positive lymphoid cells population was 31% and showed reactivity to Pan-B-markers with lambda light chain restriction. Janus Kinase 2 (JAK 2) mutation was detected while BCR-ABL1 translocation was negative. A diagnosis of ET progressing to myelofibrosis and mature B-lymphoproliferative disorder was made. Hydroxyurea and allopurinol were stopped while ruxolitinib was introduced and 2.5 years later he remains stable on this treatment.

Ischemic stroke as a presenting manifestation of polycythemia vera: a narrative review

Polycythemia vera (PV) is a myeloproliferative disorder associated with an increased risk of cerebrovascular diseases. In this narrative review, we aimed to analyze the relationships between acute ischemic stroke and PV. We conducted a PubMed/Medline and Web of Sciences Database search using MeSH major terms. We found 75 articles and finally considered 12 case reports and 11 cohort studies. The ischemic stroke resulted as the first manifestation of PV in up to 16.2% of cases; the cumulative rate of cerebrovascular events was up to 5.5 per 100 persons per year and stroke accounted for 8.8% of all PV-related deaths; age, mutations, and a previous history of thrombosis were the main risk factors. The best approach to reduce stroke recurrence risk is unclear, even if some evidence suggests a potential role of lowering hematocrit below 45%. Ischemic stroke represents one of the most common PV manifestations but, despite their relationship, patients with both diseases have a very heterogeneous clinical course and management. PV-related strokes often remain underdiagnosed, especially for the low prevalence of PV. An early diagnosis could lead to prompt treatment with phlebotomy, cytoreduction, and low-dose aspirin to decrease the risk of recurrences. Clinicians should be aware of PV as a risk factor for stroke when approaching the differential diagnosis of cryptogenic strokes. An early diagnosis could positively influence patients' management and clinical outcomes. Further studies are required to evaluate the role of PV treatments in the prevention of cerebrovascular disease.

Improving the investigative approach to polycythaemia vera: a critical assessment of current evidence and vision for the future

Polycythaemia vera is a challenging disease to study given its low prevalence and prolonged time-to-event for important clinical endpoints such as thrombosis, progression, and mortality. Although researchers in this space often rise to meet these challenges, there is considerable room for improvement in the analysis of retrospective data, the development of risk-stratification tools, and the design of randomised controlled trials. In this Viewpoint, we review the evidence behind the contemporary approach to risk stratification and treatment of polycythaemia vera. Frameworks for using data more efficiently, constructing more nuanced prognostic models, and overcoming challenges in clinical trial design are discussed.

Transformation of Polycythemia Vera to Pure Erythroid Leukemia

Pure erythroid leukemia (PEL) is an aggressive and exceedingly rare form of acute leukemia characterized as a neoplastic proliferation of immature cells committed to the erythroid lineage. It has a poor overall median survival of two to three months. To our knowledge, there are currently only a handful of reports of PEL arising from polycythemia vera. Most reported cases have been associated with radiation therapy or chemotherapeutic alkylating agents. Here we report a rare occurrence of polycythemia vera treated with phlebotomy and hydroxyurea that underwent leukemic transformation to pure erythroid leukemia.

Myeloproliferative neoplasms treated with hydroxyurea, pegylated interferon alpha-2A or ruxolitinib: clinicohematologic responses, quality-of-life changes and safety in the real-world setting

Introduction: Real-world data of responses, quality-of-life (QOL) changes and adverse events in patients with myeloproliferative neoplasms (MPN) on conventional therapy (hydroxyurea ± anagrelide), pegylated interferon alpha-2A (PEG-IFNα-2A) or ruxolitinib are limited. Methods: We prospectively studied MPN patients receiving conventional therapy, PEG-IFNα-2A or ruxolitinib. Next-generation sequencing of 69 myeloid-related genes was performed. Clinicohematologic responses, adverse events, and QOL (determined by the Myeloproliferative Neoplasm Symptom Assessment Form Total Symptom Score, MPN-SAF TSS) were evaluated. Results: Seventy men and fifty-five women with polycythemia vera (PV) (N = 23), essential thrombocythemia (ET) (N = 56) and myelofibrosis (MF) (N = 46) were studied for a median of 36 (range: 19-42) months. In PV, responses were comparable for different modalities. CREBBP mutations were associated with inferior responses. In ET, PEG-IFNα-2A resulted in superior clinicohematologic complete responses (CHCR) (P = 0.045). In MF, superior overall response rates (ORR) were associated with ruxolintib (P = 0.018) and JAK2V617F mutation (P = 0.04). For the whole cohort, ruxolitinib led to rapid and sustained reduction in spleen size within the first 6 months, and significant improvement of QOL as reflected by reduction in MPN-SAF TSS (P < 0.001). Adverse events of grades 1-2 were observed in 44%, 62% and 20% of patients receiving conventional therapy, PEG-IFNα-2A and ruxolitinib respectively; and of grade 3-4 in 7% and 9% of patients receiving PEG-IFNα-2A and ruxolitinib. Conclusions: Conventional therapy, PEG-IFNα-2A and ruxolitinib induced responses in all MPN subtypes. PEG-IFNα-2A led to superior CHCR in ET; whereas ruxolitinib resulted in superior ORR in MF, and significant reduction in spleen size and improvement in QOL.

A Rare Association Between Prostate Cancer and Polycythemia Vera

The association of polycythemia vera (PV) and localized prostate cancer is uncommon. PV is one of the myeloproliferative neoplasms that is characterized by an increased red cell mass and uncontrolled formation of blood cells owing to an acquired mutation in Janus kinase-2. PV has numerous complications and could raise the hazard of other tumors. Here, we report an extremely rare association of localized prostate cancer in a 62-year-old male with PV. He was treated by CyberKnife surgery and completed four doses of goserelin and radiotherapy, his follow up Magnetic Resonance Imaging (MRI) four months after completion of treatment showed no recurrence, and the PV was treated with hydroxyurea 500 mg twice per day and repeated phlebotomies, when needed, to keep his hematocrit level under 45%.

Inhibitors of the blood coagulation process in patients with essential thrombocythemia

: The aim of the study was to assess the activity of protein C, protein S and tissue factor pathway inhibitor in relation to the risk factors for thrombotic complications in patients with essential thrombocythemia.The study group consisted of 45 newly diagnosed patients with essential thrombocythemia. Protein S activity was determined by chromogenic method. Activities of protein C and tissue factor pathway inhibitor (TFPI) were determined using ELISAs.Significantly lower protein C and protein S activity but higher TFPI activity were found in patients with ET in comparison with the control group. TFPI activity was higher in women as compared to men, and in patients over 60 years of age compared with patients below 60 years of age. TFPI activity was higher in patients with leukocytes count at least 11 g/l than in patients with leukocytes count below 11 g/l and the difference almost reached statistical significance. Significantly lower protein C activity was found in patients with the JAK2V617F mutation, in comparison with essential thrombocythemia patients JAK2V617F (-).The reduced protein C and protein S activity may be one of the pathogenic factors of increased prothrombotic state in essential thrombocythemia patients. The decreased protein C activity in patients with the JAK2 V617F mutation seems to confirm the significant role of this mutation in the pathogenesis of thrombotic complications in essential thrombocythemia patients. Significantly increased TFPI activity in essential thrombocythemia patients above 60 years of age and with leukocyte count above 11 g/l expresses the activation of the compensatory mechanism for increased prothrombotic activity.

Specific mechanisms of subarachnoid hemorrhage accompanied by ischemic stroke in essential thrombocythemia: two case reports and a literature review

BACKGROUND

JAK2 V617F mutation increases the risk of thrombosis, and both ischemic and hemorrhagic strokes can occur in essential thrombocythemia (ET). The mechanisms underlying ischemic stroke in ET are diverse, and hemorrhagic stroke has rarely been reported in ET.

METHODS

Among 627 stroke patients, those identified as having ET were investigated retrospectively. A comprehensive systemic literature search of the PubMed database was also conducted.

RESULTS

Two cases were extracted with the diagnosis of ET who developed SAH and then ischemic stroke. In Case 1, a 47-year-old woman developed SAH in the left high convexity. Eleven hours later, acute cerebellar infarction suddenly developed due to right vertebral artery dissection. In Case 2, a 70-year-old woman developed SAH in the right high convexity. Magnetic resonance angiography showed multifocal stenotic changes in intracranial arteries. Three days later, she developed acute brain infarcts in the right middle cerebral artery territory. Eight weeks later, multifocal stenotic lesions improved. The literature review revealed 5 patients with hemorrhagic stroke and 40 patients with ischemic stroke associated with ET. Age at onset varied, female gender predominated, and the frequency of JAK2 V617F mutation was high. Atherosclerotic vascular risk factors were more common in ischemic stroke, but not in hemorrhagic stroke.

CONCLUSIONS

The current study describes rare cases of SAH accompanied by ischemic stroke secondary to ET along with a review of the current literature, implying specific mechanisms for cerebral artery disorders associated with JAK2 V617F mutation.

Recommendations for the diagnosis and treatment of patients with polycythaemia vera

OBJECTIVES

To present the Central European Myeloproliferative Neoplasm Organisation (CEMPO) treatment recommendations for polycythaemia vera (PV).

METHODS

During meetings held from 2015 through 2017, CEMPO discussed PV and its treatment and recent data.

RESULTS

PV is associated with increased risks of thrombosis/thrombo-haemorrhagic complications, fibrotic progression and leukaemic transformation. Presence of Janus kinase (JAK)-2 gene mutations is a diagnostic marker and standard diagnostic criterion. World Health Organization 2016 diagnostic criteria for PV, focusing on haemoglobin levels and bone marrow morphology, are mandatory. PV therapy aims at managing long-term risks of vascular complications and progression towards transformation to acute myeloid leukaemia and myelodysplastic syndrome. Risk stratification for thrombotic complications guides therapeutic decisions. Low-risk patients are treated first line with low-dose aspirin and phlebotomy. Cytoreduction is considered for low-risk (phlebotomy intolerance, severe/progressive symptoms, cardiovascular risk factors) and high-risk patients. Hydroxyurea is suspected of leukaemogenic potential. IFN-α has demonstrated efficacy in many clinical trials; its pegylated form is best tolerated, enabling less frequent administration than standard interferon. Ropeginterferon alfa-2b has been shown to be more efficacious than hydroxyurea. JAK1/JAK2 inhibitor ruxolitinib is approved for hydroxyurea resistant/intolerant patients.

CONCLUSIONS

Greater understanding of PV is serving as a platform for new therapy development and treatment response predictors.

The targeted histone deacetylase inhibitor tefinostat (CHR-2845) shows selective in vitro efficacy in monocytoid-lineage leukaemias

Tefinostat (CHR-2845) is a novel monocyte/macrophage-targeted histone deacetylase (HDAC) inhibitor which is cleaved into its active acid by the intracellular esterase human carboxylesterase-1 (hCE-1). The in vitro efficacy of tefinostat was characterised in cell lines and in a cohort of 73 primary AML and CMML samples. Dose-dependent induction of apoptosis and significant growth inhibitory effects were seen in myelomonocytic (M4), monocytic/monoblastic (M5) and CMML samples in comparison to non-monocytoid AML sub-types (p = 0.007). Importantly, no growth inhibitory effects were seen in normal bone marrow CD34⁺ cells exposed to AML-toxic doses of tefinostat in clonogenic assays. Expression of hCE-1 was measured by intracellular flow cytometry and immunoblotting across the cohort, with highest levels seen in M5 AML patients. hCE-1 levels correlated with significantly increased tefinostat sensitivity (low EC50) as measured by growth inhibition assays (p = 0.001) and concomitant elevation of the mature monocytoid marker CD14⁺. Strong induction of intracellular histone protein acetylation was observed in tefinostat-responsive samples, as were high levels of the DNA damage sensor γ-H2A.X, highlighting potential biomarkers of patient responsiveness. Synergistic interaction between tefinostat and the current standard treatment cytarabine was demonstrated in dose response and clonogenic assays using simultaneous drug addition in primary samples (median Combination Index value = 0.51). These data provide a strong rationale for the further clinical evaluation of tefinostat in monocytoid-lineage haematological neoplasms including CMML and monocyte-lineage AMLs.

Clinical Manifestation of Calreticulin Gene Mutations in Essential Thrombocythemia without Janus Kinase 2 and MPL Mutations: A Chinese Cohort Clinical Study

BACKGROUND

Recently, calreticulin (CALR) gene mutations have been identified in patients with essential thrombocythemia (ET). A high-frequency of ET cases without Janus kinase 2 (JAK2) mutations contain CALR mutations and exhibit clinical characteristics different from those with mutant JAK2. Thus, we investigated the frequency and clinical features of Chinese patients of Han ethnicity with CALR mutations in ET.

METHODS

We recruited 310 Chinese patients of Han ethnicity with ET to analyze states of CALR, JAK2V617F, and MPLW515 mutations by polymerase chain reaction and direct sequencing. We analyzed the relationship between the mutations and clinical features.

RESULTS

CALR, JAK2V617F, and MPLW515 mutations were detected in 30% (n = 92), 48% (n = 149), and 1% (n = 4) of patients with ET, respectively. The mutation types of CALR involved deletion and insertion of base pairs. Most of them were Type 1 (52-bp deletion) and Type 2 (5-bp insertion, TTGTC) mutations, leading to del367fs46 and ins385fs47, respectively. The three mutations were exclusive. Clinically, patients with mutated CALR had a lower hemoglobin level, lower white blood cell (WBC) count, and higher platelet count compared to those with mutated JAK2 (P < 0.05). Furthermore, a significant difference was found in WBCs between wild-type patients (triple negative for JAK2, MPL, and CALR mutations) and patients with JAK2 mutations. Patients with CALR mutations predominantly clustered into low or intermediate groups according to the International Prognostic Score of thrombosis for ET (P < 0.05).

CONCLUSIONS

CALR mutations were frequent in Chinese patients with ET, especially in those without JAK2 or MPL mutations. Compared with JAK2 mutant ET, CALR mutant ET showed a different clinical manifestation and an unfavorable prognosis. Thus, CALR is a potentially valuable diagnostic marker and therapeutic target in ET.

Kinase signaling and targeted therapy for primary myelofibrosis

The myeloproliferative neoplasms (MPNs) are somatic mutation-driven hematologic malignancies characterized by bone marrow fibrosis and the accumulation of atypical megakaryocytes with reduced polyploidization in the primary myelofibrosis subtype of the MPNs. Increasing evidence points to a dominant role of abnormal megakaryocytes in disease initiation and progression. Here we review the literature related to kinase signaling pathways relevant to megakaryocyte differentiation and proliferation, including Aurora A kinase, RhoA/ROCK, and JAK/STAT, as well as the activities of their targeted inhibitors in models of the disease. Some of these pathway inhibitors selectively induce megakaryocyte differentiation, suppress malignant proliferation, and promote polyploidization and proplatelet formation. Moreover, combining sets of these inhibitors may be an effective approach to treat and potentially cure MPN patients. For example, preclinical studies reported significant synergistic effects of the combination of an Aurora A inhibitor and JAK1/2 inhibitor, in a murine model of the primary myelofibrosis. Future basic and clinical research into the contributions of these signaling pathways to aberrant megakaryopoiesis may lead to novel effective treatments for MPN patients.

Role of tyrosine-kinase inhibitors in myeloproliferative neoplasms: comparative lessons learned

An important pathogenetic distinction in the classification of myeloproliferative neoplasms (MPNs) is the presence or absence of the BCR–ABL fusion gene, which encodes a unique oncogenic tyrosine kinase. The BCR–ABL fusion, caused by the formation of the Philadelphia chromosome (Ph) through translocation, constitutes the disease-initiating event in chronic myeloid leukemia. The development of successive BCR–ABL-targeted tyrosine-kinase inhibitors has led to greatly improved outcomes in patients with chronic myeloid leukemia, including high rates of complete hematologic, cytogenetic, and molecular responses. Such levels of treatment success have long been elusive for patients with Ph-negative MPNs, because of the difficulties in identifying specific driver proteins suitable as drug targets. However, in recent years an improved understanding of the complex pathobiology of classic Ph-negative MPNs, characterized by variable, overlapping multimutation profiles, has prompted the development of better and more broadly targeted (to pathway rather than protein) treatment options, particularly JAK inhibitors. In classic Ph-negative MPNs, overactivation of JAK-dependent signaling pathways is a central pathogenic mechanism, and mutually exclusive mutations in JAK2, MPL, and CALR linked to aberrant JAK activation are now recognized as key drivers of disease progression in myelofibrosis (MF). In clinical trials, the JAK1/JAK2 inhibitor ruxolitinib – the first therapy approved for MF worldwide – improved disease-related splenomegaly and symptoms independent of JAK2^V617F mutational status, and prolonged survival compared with placebo or standard therapy in patients with advanced MF. In separate trials, ruxolitinib also provided comprehensive hematologic control in patients with another Ph-negative MPN – polycythemia vera. However, complete cytogenetic or molecular responses with JAK inhibitors alone are normally not observed, underscoring the need for novel combination therapies of JAK inhibitors and complementary agents that better address the complexity of the pathobiology of classic Ph-negative MPNs. Here, we discuss the role of tyrosine-kinase inhibitors in the current MPN-treatment landscape.

Risk of second primary malignancies in a population-based study of adult patients with essential thrombocythemia

AIM: To determine the risk of second primary malignancy (SPM) and survival of patients with essential thrombocythemia (ET).

METHODS: We identified all patients with ET diagnosed during 2001 to 2011 from the Surveillance, Epidemiology and End Results (SEER) 18 database. Actuarial and relative survival methods were used to calculate the survival statistics. We utilized the SEER 13 database to calculate SPM. We used multiple primary standardized incidence ratio (SIR) session of the SEER*Stat software (version 8.1.5) to calculate SIR and excess risk of SPM for ET patients.

RESULTS: Age standardized five-year cause-specific survival was greater for patients < 50 years vs those ≥ 50 years (99.4% vs 93.5%, P < 0.01). Five-year cause-specific survival was lower for men vs women (70.2% vs 79.7%). A total of 201 patients (2.46%) developed SPM at a median age of 75 years. SPMs occurred at an observed/expected (O/E) ratio of 1.26 (95%CI: 1.09-1.45, P = 0.002) with an absolute excess risk (AER) of 37.44 per 10000 population. A significantly higher risk was noted for leukemia (O/E 3.78; 95%CI: 2.20-6.05, P < 0.001; AER 11.28/10000).

CONCLUSION: ET patients have an excellent cause-specific five-year survival but are at an increased risk of SPM, particularly leukemia, which may contribute to excess deaths.

New Therapeutic Approaches in Polycythemia Vera

Polycythemia vera (PV) is 1 of the 3 Philadelphia-negative myeloproliferative neoplasms. Clinically, PV is an indolent disease, but its course can be complicated by arterial and venous vascular incidents, evolution to myelofibrosis, or leukemic transformation. Treatment of PV is therefore aimed at preventing such acute complications. The cornerstone of therapy of low-risk patients remains strict control of cardiovascular risk factors, the use of phlebotomy, and low-dose aspirin. Higher-risk patients should also receive cytoreductive treatments. Hydroxyurea and interferon α represent standard first-line options for newly diagnosed high-risk PV patients. Recommendations for patients whose disease fails to respond to these therapies are less clearly defined. The discovery of a mutation in the Janus kinase (JAK) 2 gene (V617F) in almost all cases of PV has prompted the development of molecularly targeted agents for the treatment of these patients. In this review, we discuss key clinical aspects, the current therapeutic armamentarium, and data on the use of novel agents in patients with PV.

The 2016 revision of WHO classification of myeloproliferative neoplasms: Clinical and molecular advances

Clinical evidence supports the need of changing the diagnostic criteria of the 2008 updated WHO classification for polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (PMF). In JAK2-mutated patients who show characteristic bone marrow (BM) morphology, clinical studies demonstrated that a hemoglobin level of 16.5g/dL in men and 16.0g/dl for women or a hematocrit value of 49% in men and 48% in women are the optimal cut off levels for distinguishing JAK2-mutated ET from "masked/prodromal" PV. Therefore BM morphology was upgraded to a major diagnostic criterion. Regarding ET the key issue was to improve standardization of prominent BM features enhancing differentiation between "true" ET and prefibrotic/early primary myelofibrosis (prePMF). These two entities have shown a different epidemiology and clinical outcomes. Concerning prePMF a more explicit clinical characterization of minor criteria is mandated for an improved distinction from ET and overt PMF and accurate diagnosis and outcome prediction.

Ruxolitinib: a targeted treatment option for patients with polycythemia vera

Polycythemia vera (PV) is a chronic myeloproliferative neoplasm characterized by erythrocytosis and the presence of Janus kinase (JAK) 2V617F or similar mutations. This review summarizes the pathophysiology of PV, the challenges associated with traditional treatment options, and the scientific rationale and supportive clinical evidence for targeted therapy with ruxolitinib. Accumulating evidence indicates that activating mutations in JAK2 drive the PV disease state. Traditional PV treatment strategies, including aspirin, phlebotomy, and cytoreduc­tive agents such as hydroxyurea, provide clinical benefits for some but not all patients and may not adequately treat PV-related symptoms. Furthermore, traditional treatment approaches are associated with potential side effects that may limit their usage and lead some patients to discon­tinue the treatment. Ruxolitinib is an orally available small-molecule tyrosine kinase inhibitor that is a potent and selective inhibitor of JAK1/JAK2. Ruxolitinib is approved in the US for patients with PV with an inadequate response or intolerance to hydroxyurea and in Europe for adults with PV who are resistant to or intolerant of hydroxyurea. In the Phase III RESPONSE registration trial, ruxolitinib was superior to the best available therapy in patients with PV who were resistant to or intolerant of hydroxyurea in controlling hematocrit levels, reducing spleen volume, and improving PV-related symptoms and quality-of-life measures. The most common nonhematologic adverse events in ruxolitinib-treated patients were headache, diarrhea, pruritus, and fatigue in the RESPONSE trial; hematologic adverse events were primarily grade 1 or 2. In the Phase IIIb nonregistration RELIEF trial, there were nonsignificant trends toward an improved symptom control in patients with PV on a stable hydroxyurea dose who were generally well controlled but reported disease-associated symptoms and switched to ruxolitinib vs those who continued hydroxyurea therapy. Updated treatment guidelines will be important for educating physicians about the role of ruxolitinib in the treatment of patients with PV.

γ-Glutamyl Transferase Is an Independent Biomarker of Splanchnic Thrombosis in Patients With Myeloproliferative Neoplasm

Myeloproliferative neoplasms (MPNs) are associated with an increased risk of thrombotic events and constitute the major risk factor of splanchnic venous thrombosis (SVT) in Western countries. Although timely anticoagulation resolves SVT, unrecognized SVT frequently leads to portal hypertension and, potentially, variceal bleeding, which may render anticoagulation difficult. Thus, early identification of SVT development is clinically relevant in MPN patients.In this retrospective analysis, we included 126 patients with MPN and/or SVT referred to our hospital between 2009 and 2014. A total of 86 patients diagnosed with MPN formed the first cohort (PV n = 18, ET n = 16, and MF n = 40), whereas 40 patients who had SVT without adjunct MPN formed a control cohort. Median follow-up period was 960 days. Clinical and laboratory data were collected and analyzed for the identification of potential biomarkers applying descriptive statistics, nonparametric testing, Kaplan-Meier, and logistic regression analysis. The relevance of the identified biomarkers was evaluated in an independent 2nd cohort of 181 patients from the MPN registry of the Study Alliance of Leukemia (SAL-MPN).Thirty-three MPN patients (38%) in the 1st cohort had SVT. Elevated levels of aspartate aminotransferase, alanine aminotransferase, serum bilirubin, or γ-GT were significantly correlated to the presence of SVT. In multivariate testing, CRP and aspartate aminotransferase were predictors for survival and γ-GT remained the only significant variable associated with SVT in MPN patients (P < 0.05). These findings were confirmed in the 2nd cohort comprising 42% of patients with MPN suffering from SVT.Elevated γ-GT levels indicate SVT in MPN patients, whereas CRP levels are independent predictors of patient survival.

Pruritus in primary myelofibrosis: management options in the era of JAK inhibitors

Primary myelofibrosis (PMF)-associated pruritus is often severe and requires treatment. Fifty-one patients with bone marrow-proven PMF with associated pruritus were identified from a primary cohort of patients with PMF (n = 566) seen at our institution. We conducted a retrospective review of the clinical characteristics, severity of pruritus, type of treatment, and response of these patients. Thirty-two out of 51 patients (63 %) reported severe PMF-associated pruritus and required a total of 108 treatment episodes, with complete response (CR), partial response (PR) and no response (NR) observed in 22, 23, and 55 % of episodes, respectively. The most common treatment categories included JAK inhibitors (n = 19), anti-depressants (n = 18), and antihistamines (n = 17). Highest CR rates were observed in patients treated with a JAK inhibitor (53 %) and immunomodulatory drugs (IMiDS (50 %)). Emerging targeted therapies may result in better symptom control and higher response rates in patients suffering from severe PMF-associated pruritus.

Determination of prognosis of Philadelphia chromosome-negative myeloproliferative neoplasms with a simple clinical examination: Retrospective analysis of 71 patients in a single institution

Philadelphia chromosome-negative myeloproliferative neoplasms (MPNs), including polycythemia vera (PV), essential thrombocytosis (ET) and primary myelofibrosis (PMF), are clonal hematopoietic diseases. A single-institution retrospective analysis was performed, including 71 MPN patients diagnosed at the Hakodate Municipal Hospital between April, 2001 and April, 2014, and certain clinical characteristics were identified as effective prognostic factors. The patients were categorized by risk factor scoring based on age, number of abnormal blood cell lineages and splenomegaly at diagnosis, and the association between this categorization and prognosis was analyzed using a statistical procedure. The effect of Janus kinase 2 (JAK2) V617F mutation on prognosis was also investigated. The MPN patients were consolidated into three risk groups based on the margin of intergroup survival differences: i) Score 1-2 (n=23), ii) score 3 (n=24) and iii) score 4-5 (n=24). MPN patients with scores of 4 or 5 exhibited poorer overall survival (OS) compared with those with lower scores (P<0.001). In addition, there were significant differences in event-free survival (EFS) among scoring groups (P=0.0059). PV and ET had a better prognosis compared with PMF, although this analysis suggested that PV and ET patients with scores of 4 or 5 may have a poorer prognosis in terms of OS (P=0.0052) and EFS (P=0.022) and should be closely followed up. We observed no significant prognostic effect of the JAK2V167F mutation for OS (P=0.28) or EFS (P=0.17). Our results suggested that a simple scoring system based on age, blood cell counts and presence of splenomegaly at diagnosis may be used for the long-term prognosis of MPN patients.

Myocardial infarction as a thrombotic complication of essential thrombocythemia and polycythemia vera

OBJECTIVE

Detailed analyses of clinical characteristics of myocardial infarction (MI) as an essential thrombocythemia (ET)- and polycythemia vera (PV)-related complication have been so far presented mostly as case reports. Therefore, the aim of this retrospective analysis was to evaluate the main cardiological and hematological characteristics for better understanding myocardial complications in ET/PV.

METHODS

A retrospective analysis was carried out involving 263 patients diagnosed with ET or PV (155/108) between 1998 and 2014. Fourteen patients suffered MI during the hematological follow-up. Their clinical characteristics were compared to 162 patients (97 ET and 65 PV patients) who did not exhibit any major thrombotic complications (MI, stroke/transient ischemic attack, and venous events) before or after hematological diagnosis of ET/PV.

RESULTS

Fourteen MI events occurred among the 263 patients (5.3%). Vascular risk factors were found in 92.9% (13/14) of analyzed cases. In all, 71.4% of the MI complications developed within 12 months after the diagnosis of ET/PV. The coronary angiography findings revealed ST-elevation MI in four cases and non-ST-elevation MI in 10. Significant stenosis of coronary arteries requiring percutaneous coronary intervention with a stent implantation was present in seven cases, while three had complex stenoses or previous grafts/stents. All of them had undergone coronary artery bypass graft operations.

CONCLUSION

The results of the present study suggest that early detection and consideration of individual management of vascular risk factors in ET/PV patients are also important. Furthermore, a better theoretic understanding of platelet activation and role of leukocytes in myeloproliferative neoplasm-related thrombosis could open new perspectives in thrombosis prediction and prevention.

Thrombotic risk assessment in 185 WHO-defined essential thrombocythemia patients: single center experience

Thrombosis risk in essential thrombocythemia (ET) patients can be assessed using different prognostic systems. Conventional risk factors include age more than 60 years and history of previous thrombosis. In addition, other factors such as JAK2 V617F mutations, cardiovascular risk factors, leukocytosis more than 11 × 10⁹/l, thrombophilic factors and platelet count more than 1500 × 10⁹/l are used in different hematology centers as high-risk features for thrombosis. Our study compared different risk model groups for thrombosis in 185 WHO-defined ET patients at the Hospital of Lithuanian University of Health Sciences Kaunas Klinikos. We found that patient distribution in low, intermediate- and high-risk groups varies using different risk stratification models. The biggest difference in risk assignment is evident in patients who are older than 60 years and have no other risk factors and in patients who are younger than 60 years but have other risk factors.

This observation suggests that new prospective randomized clinical trials are needed to better stratify patients at risk for thrombosis.

Postpartum haemorrhage in a woman with essential thrombocythemia carrying calreticulin mutation: a case report

Coagulation disorder associated with essential thrombocythemia may exacerbate the prothrombotic state physiologically occurring during pregnancy. We report a case of a severe postpartum haemorrhage in a 35-year-old woman previously diagnosed with essential thrombocythemia and carrying the somatic calreticulin mutation. She was referred to our Thrombosis and Haemostasis Unit for pregnancy management. A treatment with low-dose aspirin was prescribed until the labour started, as the platelets count raised above 1000 × 10/l. At the time of bleeding, no residual placenta was detected at the revision of the uterine cavity.Although the postpartum is a high-risk period for thrombotic events, we have to carefully evaluate in women with essential thrombocythemia the likelihood of developing a hemorrhagic complication.

Management of symptoms in polycythemia vera and essential thrombocythemia patients

The BCR-ABL-negative myeloproliferative neoplasms (MPNs) are clonal stem cell derived malignancies, which include polycythemia vera (PV), essential thrombocythemia (ET), and myelofibrosis (MF). The MPNs are characterized by dysregulated JAK-STAT signaling pathways. PV and ET are associated with an increased risk of thrombo-hemorrhagic complications, risk of progression to MF and leukemia. Presentation of patients with PV and ET is variable and usually as a result of abnormal full blood count indices (raised hemoglobin and hematocrit, leukocytosis, and thrombocytosis). Presentation with thrombosis or splenomegaly occurs in ∼30% of patients. Historically thought of as indolent compared with MF, patients with PV and ET have significant disease symptom burden which does not directly correlate to the current clinical prognostic classifications. The mainstay of therapy is reserved for patients with high-risk disease and thus excludes a population of patients with significant symptom related morbidity impacting their quality-of-life and survival. Recent treatment strategies have aimed to incorporate disease burden assessment into the selection of therapeutic interventions such as JAK2 inhibitors and HDAC inhibitors. We will review the advances in the field of MPN symptom assessment and symptom burden experienced by ET and PV patients. We will also discuss the risk-stratified management of ET and PV patients alongside symptom assessment and the impact of potential novel therapies, for patients who fail to respond to conventional treatment.

Interferon-α induces marked alterations in circulating regulatory T cells, NK cell subsets, and dendritic cells in patients with JAK2V617F-positive essential thrombocythemia and polycythemia vera

Long-term therapy with IFN-α2 is associated with sustained major molecular remissions in JAK2-positive ET and PV. The efficacy of IFN-α2 may be partly mediated by modulation of immune cells, which was investigated in twenty patients with ET (n = 6) and PV (n = 14). The frequency of CD4(+) CD25(+) Foxp3(+) T cells was significantly increased during IFN-α2 treatment in all patients (P < 0.0001). A significant expansion of the CD56(bright) NK cells (P = 0.0002) and a concomitant decrease in the frequency of CD56(dim) NK cells (P < 0.0001) were also detected. Myeloid DCs (mDCs) and plasmacytoid DCs (pDCs) were studied in nine patients, and decreased frequencies of both cell types were observed during the course of treatment. On both mDCs and pDCs, HLA-ABC expression was upregulated (P = 0.003), but decreasing expression levels of HLA-DR was detected on mDCs. The expression of CD40 (P = 0.002), CD83 (P = 0.03), and CD86 (P = 0.01) increased, but was confined to pDCs. Furthermore, PD-L1 expression was reduced on mDC (P = 0.003) and increased on pDCs (P = 0.02). No significant correlations were found between the changes in immune cells and hematological or molecular responses achieved in our cohort of patients. So forth, it remains to be revealed whether the profound changes in circulating immune cells contribute to the beneficial effects of long-term IFN-α2 treatment in some patients.

Acquired JAK-2 V617F Mutational Analysis in Pakistani Patients with Essential Thrombocythemia

BACKGROUND

Essential thrombocythemia (ET) is a clonal hemopoietic stem cell myeloproliferative neoplasm characterized by persistent thrombocytosis along with megakaryocytic hyperplasia. In the last decade following the identification of an acquired JAK2 V617F mutation, there has been acceleration in our understanding of this disease. The rational of this study was to determine the mutational profile of JAK2 V617F in Pakistan patients with ET.

MATERIALS AND METHODS

In this retrospective cross sectional study, 21 patients with ET were enrolled from January 2011 to December 2014. Patients were diagnosed based on WHO criteria for essential thrombocythemia. Complete blood count was done on an automated hematology analyzer, while JAK2 V617F expression was evaluated by polymerase chain reaction.

RESULTS

The mean age was 56.7±19.0 years (range 18-87) and the male to female ratio was 1:1.1. The frequency of JAK2 V617F positivity in our ET patients was found to be 61.9%. The mean hemoglobin was 11.7±2.4 g/dl with a total leukocyte count of 13.3±8.1x109/l and a platelet count of 1188±522x109/l. Positive correlations for JAK2 V617F mutation were established with high TLC count and raised LDH (P<0.05). No correlation of JAK2 V617F could be established with age and gender (P>0.05).

CONCLUSIONS

JAK2 V617F mutation frequency in our ET patients was similar to those reported previously. Screening for the mutation in all suspected essential thrombocythemia cases could be beneficial in differentiating patients with reactive and clonal thrombocytosis.

MPNs as Inflammatory Diseases: The Evidence, Consequences, and Perspectives

In recent years the evidence is increasing that chronic inflammation may be an important driving force for clonal evolution and disease progression in the Philadelphia-negative myeloproliferative neoplasms (MPNs), essential thrombocythemia (ET), polycythemia vera (PV), and myelofibrosis (MF). Abnormal expression and activity of a number of proinflammatory cytokines are associated with MPNs, in particular MF, in which immune dysregulation is pronounced as evidenced by dysregulation of several immune and inflammation genes. In addition, chronic inflammation has been suggested to contribute to the development of premature atherosclerosis and may drive the development of other cancers in MPNs, both nonhematologic and hematologic. The MPN population has a substantial inflammation-mediated comorbidity burden. This review describes the evidence for considering the MPNs as inflammatory diseases, A Human Inflammation Model of Cancer Development, and the role of cytokines in disease initiation and progression. The consequences of this model are discussed, including the increased risk of second cancers and other inflammation-mediated diseases, emphasizing the urgent need for rethinking our therapeutic approach. Early intervention with interferon-alpha2, which as monotherapy has been shown to be able to induce minimal residual disease, in combination with potent anti-inflammatory agents such as JAK-inhibitors is foreseen as the most promising new treatment modality in the years to come.

Bleeding complications in BCR-ABL negative myeloproliferative neoplasms: prevalence, type, and risk factors in a single-center cohort

The BCR-ABL1-negative myeloproliferative neoplasms (MPN) share an increased risk of thrombotic and hemorrhagic complications. Risk factors for hemorrhage are less well defined than those for thrombosis. Because patients with CALR mutations have higher platelet counts compared to JAK2 V617F-mutated patients, bleeding rates may be increased in this group. Our aim was to retrospectively evaluate whether acquired von Willebrand disease (AvWD), thrombocytosis, mutational status, or treatment history are associated with bleeding in a cohort of MPN patients. Using an electronic database, MPN patients seen between 2005 and 2013 were retrospectively identified using ICD-9 codes and billing records. A bleeding event was defined as one that was identified in the medical record and graded based on the Common Terminology Criteria for Adverse Event (CTCAE) version 4.0. Among 351 MPN patients, 15.6 % experienced 64 bleeding event types. There was no association of bleeding with mutational status, gender, MPN subtype, aspirin use, prior thrombosis, or platelet count at presentation. There was an association between bleeding and older age at diagnosis. aVWD was identified in six patients. In this single-center retrospective study, bleeding events were identified in 15 % of patients, and associated with older age at diagnosis. aVWD was rarely tested for in this cohort.

Concurrent Ruptured Pseudoaneurysm of the Internal Carotid Artery and Cerebral Infarction as an Initial Manifestation of Polycythemia Vera

The most common neurologic manifestations of polycythemia vera (PV) are cerebral infarction and transient ischemic attacks, while cerebral hemorrhage or intracranial dissection has been rarely associated with PV. Here we report the first case of a 59-year-old patient with intracranial supraclinoid internal carotid artery (ICA) dissection causing cerebral infarction and concomitant subarachnoid hemorrhage due to pseudoaneurysm rupture as clinical onset of PV. This case report discusses the possible mechanism and treatment of this extremely rare condition.

Acquired von Willebrand syndrome in a case of polycythemia vera resulting in recurrent and massive bleeding events in the pleural and abdominal cavity

A 52-year-old woman was admitted to the hospital three times in a span of 5 years in hypovolemic shock because of spontaneous and massive bleeding in the pleural and abdominal cavity. Blood tests revealed a high number of blood cells, and bone marrow smears showed trilineage myeloproliferation. Serum erythropoietin level was decreased. Analysis revealed a V617F mutation in the JAK2 protein. Her activated partial thromboplastin time was slightly prolonged, the ratio between von Willebrand factor (vWF) propeptide and vWF antigen was in the normal range, but the ratio between vWF and ristocetin cofactor was decreased dramatically. Further investigation revealed the absence of large and intermediate vWF-multimers. She was diagnosed with polycythemia vera with acquired von Willebrand syndrome. The bleeding was stopped using a transfusion of freshly thawed plasma and cryoprecipitate.

Leukemic transformation in essential thrombocythemia

Essential thrombocythemia patients develop acute myeloid leukemia (AML) at a rate of 1-4% during a median follow-up of 7-10 years. The risk increases with advanced age, anemia, platelet count ≥ 1000 × 10(9)/l, the presence of ≥ 2 somatic mutations and after the first decade of diagnosis. The use of alkylating agents and (32)radiophosphorus, particularly in higher doses, but not hydroxyurea and anagrelide, increases the risk. AML in essential thrombocythemia patients is frequently associated with unfavorable cytogenetics and poor prognosis. In young and fit patients, AML-type induction chemotherapy followed by allogeneic stem cell transplantation may offer the best chance of long-term disease control. In select elderly patients with poor performance status, hypomethylating agent such as azacytidine may prolong survival.

Is there a role for JAK inhibitors in BCR-ABL1-negative myeloproliferative neoplasms other than myelofibrosis?

Current data suggest that constitutively active JAK-STAT signaling plays a central role in the pathogenesis of BCR-ABL1-negative myeloproliferative neoplasms (MPNs), regardless of the specific underlying molecular abnormality. This observation provides strong rationale for use of JAK inhibitors for MPN treatment, and these drugs were first tested in myelofibrosis (MF) patients. Ruxolitinib, a JAK-1/2 inhibitor, is effective at controlling splenomegaly and constitutional symptoms, but has limited benefit in reversing bone marrow fibrosis or inducing complete or partial remissions. Ruxolitinib is currently in Phase 3 testing for treatment of hydroxyurea resistant/intolerant polycythemia vera (PV). Preliminary data reveals response rates of 60% for hematocrit control and 38% for spleen volume reduction per protocol-defined criteria, in addition to improving disease-related symptoms. These endpoints however have limited value as surrogates for long-term clinically relevant outcomes such as freedom-from-cardiovascular/thrombohemorrhagic events or time-to-hematological transformation, and the early crossover design of the aforementioned trial introduces limitations in terms of analysis of these latter endpoints. In contrast, other recent trials in PV have demonstrated the feasibility of using long-term clinically relevant outcomes as a primary endpoint. We also discuss the role of JAK inhibitors for treatment of CSF3RT618I-mutated chronic neutrophilic leukemia and hematologic malignancies with rearranged JAK2 gene.

Evolving Therapeutic Options for Polycythemia Vera: Perspectives of the Canadian Myeloproliferative Neoplasms Group

Polycythemia vera (PV) is a clonal stem cell disorder characterized by erythrocytosis and associated with burdensome symptoms, reduced quality of life, risk of thrombohemorrhagic complications, and risk of transformation to myelofibrosis and acute myeloid leukemia. The discovery of the JAK2 V617 mutation marked a significant milestone in understanding the pathophysiology of the disease and subsequently the diagnostic and therapeutic approaches. The current diagnostic criteria for PV are based on hemoglobin level and presence of the JAK2 V617 mutation. The treatment is geared toward prevention of thrombotic events, normalization of blood counts, control of disease-related symptoms, and potential prolongation of survival. Cytoreductive therapy is indicated in patients at increased risk of thrombosis. Hydroxyurea (HU) remains the most commonly used first-line cytoreductive therapy and is superior to phlebotomy in reducing risk of arterial and venous thrombosis. Interferon (IFN) is used either at failure of HU or in selected patients as first-line therapy. The results of pegylated IFN in phase 2 studies appear encouraging, with molecular responses occurring in some patients. Ongoing phase 3 studies of HU versus pegylated IFN will define the optimal first-line cytoreductive therapy for PV. A recent phase 3 trial has shown the superiority of the JAK1/2 inhibitor ruxolitinib in comparison to best available treatment in HU-intolerant or -resistant patients. The therapeutic landscape of PV is likely to change in the near future. In this report, we assess the potential impact of the changing landscape of PV management on daily practice.

Qualitative and quantitative modifications of von Willebrand factor in patients with essential thrombocythemia and controlled platelet count

BACKGROUND

Essential thrombocythemia (ET) is characterized by increased platelets and prevalent thrombosis. An acquired von Willebrand factor (VWF) disease has been hypothesized and inconsistently associated with extreme thrombocytosis or rare bleeding in ET. Whether VWF is modified in ET patients with controlled platelet count remains unclear.

OBJECTIVES

We studied different VWF- and platelet-associated parameters in ET patients treated according to current recommendations.

PATIENTS/METHODS

Sixty-nine ET patients (M = 29; median age, 62 [48-70] years; platelets, 432 [337-620] × 10(3)  μL(-1) ), 69 matched controls and 10 subjects with reactive thrombocytosis (RT) were studied. VWF:antigen (Ag), activity (act), electrophoretic patterns, VWF:propeptide, plasma glycocalycin (GC), glycoproteinV (GpV), ADAMTS-13, elastase, C-reactive protein and serum thromboxane (TX)B2 were measured.

RESULTS

In ET patients, VWF:Ag was increased by 31 ± 13% vs. controls (P < 0.01), without dependence of blood groups, while VWF:act was reduced by 21 ± 12% vs. controls and by 50 ± 24% vs. RT (P < 0.01). The VWF:act/VWF:Ag ratios in ET were reduced by 35 ± 17% vs. controls and RT patients (P < 0.001) and significantly associated with: immature or total platelet counts, GC, GpV and TXB2 . In multivariable analysis, only GC inversely predicted ET patients' VWF:act/VWF:Ag ratios (β = -0.42, P = 0.01). By electrophoresis analyses, high-molecular-weight VWF multimers were variably reduced with atypical cleavage bands in ET only. VWF:propeptide, ADAMTS-13 and elastase levels were normal in ET patients. Platelet-associated ADAM-10 and ADAM-17 hydrolyzed VWFm in vitro, showing patterns similar to those in ET samples.

CONCLUSIONS

In ET patients with controlled platelet counts, the VWF:act/VWF:Ag ratio is decreased and predicted by GC, a product of platelet activation. ADAM-10 and/or ADAM-17 might be involved. In vivo platelet activation, which characterizes ET, might contribute to disease-specific VWF alterations.

Acquired familial Mediterranean fever associated with a somatic MEFV mutation in a patient with JAK2 associated post-polycythemia myelofibrosis

Background

A study was designed to identify the source of fever in a patient with post-polycythemia myelofibrosis, associated with clonal Janus Kinase 2 (JAK2) mutation involving duplication of exon 12. The patient presented with 1–2 day long self-limited periodic episodes of high fever that became more frequent as the hematologic disease progressed.

Methods

After ruling out other causes for recurrent fever, analysis of the pyrin encoding Mediterranean fever gene (MEFV) was carried out by Sanger sequencing in peripheral blood DNA samples obtained 4 years apart, in buccal cells, laser dissected kidney tubular cells, and FACS-sorted CD3-positive or depleted mononucleated blood cells. Hematopoeitc cells results were validated by targeted deep sequencing. A Sanger sequence based screen for pathogenic variants of the autoinflammatory genes NLRP3, TNFRSF1A and MVK was also performed.

Results

A rare, c.1955G>A, p.Arg652His MEFV gene variant was identified at negligible levels in an early peripheral blood DNA sample, but affected 46 % of the MEFV alleles and was restricted to JAK2-positive, polymorphonuclear and CD3-depleted mononunuclear DNA samples obtained 4 years later, when the patient experienced fever bouts. The patient was also heterozygous for the germ line, non-pathogenic NLRP3 gene variant, p.Q705K. Upon the administration of colchicine, the gold standard treatment for familial Mediterranean fever (FMF), the fever attacks subsided.

Conclusions

This is the first report of non-transmitted, acquired FMF, associated with a JAK2 driven clonal expansion of a somatic MEFV exon 10 mutation. The non-pathogenic germ line NLRP3 p.Q705K mutation possibly played a modifier role on the disease phenotype.

Current and future treatment options for polycythemia vera

Patients with polycythemia vera (PV), a myeloproliferative neoplasm characterized by an elevated red blood cell mass, are at high risk of vascular and thrombotic complications and have reduced quality of life due to a substantial symptom burden that includes pruritus, fatigue, constitutional symptoms, microvascular disturbances, and bleeding. Conventional therapeutic options aim at reducing vascular and thrombotic risk, with low-dose aspirin and phlebotomy as first-line recommendations for patients at low risk of thrombotic events and cytoreductive therapy (usually hydroxyurea or interferon alpha) recommended for high-risk patients. However, long-term effective and well-tolerated treatments are still lacking. The discovery of mutations in Janus kinase 2 (JAK2) as the underlying molecular basis of PV has led to the development of several targeted therapies, including JAK inhibitors, and results from the first phase 3 clinical trial with a JAK inhibitor in PV are now available. Here, we review the current treatment landscape in PV, as well as therapies currently in development.