Hydroxyurea for patients with essential thrombocythemia and a high risk of thrombosis

A Rare Case of Triple-Negative Essential Thrombocythemia in a Young Postsplenectomy Patient: A Diagnostic Challenge

The distinction between primary and reactive thrombocytosis by bone marrow histology is very important. Reactive thrombocytosis, the most common cause of thrombocytosis, can be expected in postsplenectomy states; however, close hematological evaluation of prolonged thrombocytosis is essential to identify patients who may have an underlying myeloproliferative neoplasm. We report a 37-year-old woman who was found to have portal, mesenteric, and splenic vein thrombosis with thrombocytosis, two months after she had a splenectomy for spontaneous splenic rupture. Other reactive conditions and myeloproliferative neoplasms (MPN) were excluded, and subsequently, the diagnosis of triple-negative essential thrombocythemia (ET) was established by bone marrow histology. This case of primary thrombocythemia following splenectomy in a young patient illustrates some of the diagnostic difficulties associated with postsplenectomy thrombocytosis. Continuing reports of anecdotal experiences in managing similar complex scenarios is essential and remains the only reference for clinicians facing these rare conditions.

Hydroxycarbamide Plus Aspirin Versus Aspirin Alone in Patients With Essential Thrombocythemia Age 40 to 59 Years Without High-Risk Features

PURPOSE

Cytoreductive therapy is beneficial in patients with essential thrombocythemia (ET) at high risk of thrombosis. However, its value in those lacking high-risk features remains unknown. This open-label, randomized trial compared hydroxycarbamide plus aspirin with aspirin alone in patients with ET age 40 to 59 years and without high-risk factors or extreme thrombocytosis.

PATIENTS AND METHODS

Patients were age 40 to 59 years and lacked a history of ischemia, thrombosis, embolism, hemorrhage, extreme thrombocytosis (platelet count ≥ 1,500 × 109/L), hypertension, or diabetes requiring therapy. In all, 382 patients were randomly assigned 1:1 to hydroxycarbamide plus aspirin or aspirin alone. The composite primary end point was time to arterial or venous thrombosis, serious hemorrhage, or death from vascular causes. Secondary end points were time to first arterial or venous thrombosis, first serious hemorrhage, death, incidence of transformation, and patient-reported quality of life.

RESULTS

After a median follow-up of 73 months and a total follow-up of 2,373 patient-years, there was no significant difference between the arms in the likelihood of patients reaching the primary end point (hazard ratio, 0.98; 95% CI, 0.42 to 2.25; P = 1.0). The incidence of significant vascular events was low, at 0.93 per 100 patient-years (95% CI, 0.61 to 1.41). There were also no differences in overall survival; in the composite end point of transformation to myelofibrosis, acute myeloid leukemia, or myelodysplasia; in adverse events; or in patient-reported quality of life.

CONCLUSION

In patients with ET age 40 to 59 years and lacking high-risk factors for thrombosis or extreme thrombocytosis, preemptive addition of hydroxycarbamide to aspirin did not reduce vascular events, myelofibrotic transformation, or leukemic transformation. Patients age 40 to 59 years without other clinical indications for treatment (such as previous thrombosis or hemorrhage) who have a platelet count < 1,500 × 109/L should not receive cytoreductive therapy.

Hydroxyurea prevents arterial and late venous thrombotic recurrences in patients with myeloproliferative neoplasms but fails in the splanchnic venous district. Pooled analysis of 1500 cases

We collected 1500 patients with myeloproliferative neoplasms (MPN) and arterial or venous thrombosis (935/565), pooling three independent cohorts previously reported. Long-term treatment with antiplatelet drugs or vitamin K-antagonists (VKA) was given to 1391 (92.7%) patients; 975 (65%) patients received hydroxyurea (HU). We recorded 348 recurrences (venous in 142 cases) over 6075 patient-years, with an incidence rate of 5.7 per 100 pt-years (95% CI 5.1-6.4). The site of the first thrombosis predicted the site of recurrence. Independent factors influencing the rate of novel arterial thrombosis were HU (HR 0.67, 95% CI 0.46-0.98), antiplatelet treatment (HR 0.54, 95% CI 0.35-0.82), and VKA (HR 0.58, 95% CI 0.35-0.96). On the contrary, the recurrence of venous thromboses was significantly diminished only by VKA (HR 0.60, 95% CI 0.37-0.95), while HU prevented late but not early recurrences after venous thrombosis at common sites. Of note, we failed to demonstrate a positive effect of HU in the prevention of recurrent splanchnic vein thrombosis. In conclusion, in MPN patients, HU plays a role in the prevention of arterial thrombosis, together with aspirin and VKA, whereas its action in the prevention of recurrent venous thrombosis is uncertain. Such findings call for future studies to optimize and personalize secondary prophylaxis after MPN-related thrombosis.

Therapeutic Approach to Young Patients With Low-Risk Essential Thrombocythemia: Primum Non Nocere

The Oncology Grand Rounds series is designed to place original reports published in the Journal into clinical context. A case presentation is followed by a description of diagnostic and management challenges, a review of the relevant literature, and a summary of the authors' suggested management approaches. The goal of this series is to help readers better understand how to apply the results of key studies, including those published in Journal of Clinical Oncology, to patients seen in their own clinical practice. A 51-year-old woman was diagnosed with essential thrombocythemia (ET) the previous year (April 2016) when she was incidentally found to have increased platelets (747 × 109/L) during a yearly physical examination. Her past medical history was significant only for mild hypertension, which was well controlled with a low dose of a β-blocker. There was no history of thromboembolic events. A JAK2V617F mutation was detected in her peripheral blood. A repeated platelet count 1 month later showed increased platelets of 871 × 109/L and she began hydroxyurea. One year later, she presented to our clinic with a white cell count of 8.9 × 109/L, hemoglobin 14 g/dL, and platelets 846 ×109/L while receiving hydroxyurea 500 mg one day alternating with 1000 mg the next day and aspirin 81 mg once per day. The differential as well as other laboratory findings were within normal limits. She had chronic mild to moderate itching, but otherwise denied symptoms referable to ET. Her physical examination was notable for the absence of palpable hepatosplenomegaly. Bone marrow aspiration and biopsy revealed normocellular marrow with hyperplastic megakaryocytes in clusters, no reticulin fibrosis, and 2% blasts, compatible with ET. Molecular testing confirmed JAK2V617F mutations at a variant allele frequency of 12% without any other mutations (81-gene panel), and her karyotype was diploid. She visited the clinic to discuss the next steps in her treatment.

Coexistent Breast Cancer and Essential Thrombocythemia: How We Addressed the Therapeutic Challenges

Essential thrombocythemia (ET) occurring with breast cancer is uncommon; the therapeutic approach varies and poses a challenge. A 65-year-old female presented to us after being diagnosed with hormone positive, HER2-negative infiltrating ductal carcinoma. She had a platelet count of 600 thou/cu mm. Her JAK2 mutation was positive. Bone marrow biopsy showed increased megakaryocytes. She was diagnosed with ET in the setting of breast cancer. She underwent breast conservation surgery after which aspirin was resumed. Anticipating thrombocytopenia during chemotherapy and given the absence of data combining hydroxyurea with standard chemotherapy used for breast cancer, we felt it prudent to delay cytoreductive therapy for her ET until after completion of breast cancer treatment. Her average platelet count during chemotherapy was 480 thou/cu mm with the lowest being 377 thou/cu mm. Her platelet count remained at goal between 300 and 350 thou/cu mm after four months of hydroxyurea.

Ruxolitinib for the Treatment of Essential Thrombocythemia

Deregulated Janus Kinase 2 (JAK2) activation is central to the pathogenesis of most myeloproliferative neoplasms (MPNs), of which essential thrombocythemia (ET) is the most common entity. Patients with ET are risk-stratified according to their risk of thrombo-hemorrhagic complications. High-risk patients are offered treatments to reduce their platelet count using cytoreductive therapy. The disease course is often long and therapy intolerance is not infrequent. Ruxolitinib, a Janus Kinase (JAK) 1/JAK2 inhibitor, has demonstrated efficacy in patients with both myelofibrosis (MF) and polycythemia vera and is well tolerated. Side effects include predictable cytopenias and an augmented risk of infections. Ruxolitinib has been investigated in a small group of ET patients who were refractory/intolerant to hydroxycarbamide (HC) and demonstrated improvements in both symptoms and splenomegaly. Of note, a proportion of treated patients (13.2%) also had a significant reduction in platelet counts. However, these results require further validation in comparison with conventional therapy. Recently, a randomized-controlled phase 2 study (MAJIC-ET) assessed the role of Ruxolitinib in patients refractory or intolerant to HC. This study revealed that Ruxolitinib demonstrated some clinical efficacy but was only superior in terms of symptom control. In clinical practice, some individuals with ET do exhaust all potential treatment options and there may well be a role for Ruxolitinib in such patients or those with a significant symptom burden. However, in the wider context the goal of therapy with the use of JAK inhibitor therapy in ET needs to be defined carefully and we explore this within this timely review article.

The real-world outcomes of treating Polycythemia Vera: Physician adherence to treatment guidelines

Therapy in Polycythemia Vera (PV), a myeloproliferative neoplasm, focuses on reducing cardiovascular (CV) risk without increasing bleeding or hematological progression. However, the real-world practice of treating PV in North America is understudied. We performed a retrospective cohort study of newly diagnosed PV (JAK2V617F mutation positive) patients in Hamilton, Canada to fill this knowledge gap. Out of 108 patients included, (n = 45, 41.7%) patients did not receive therapy consistent with contemporary treatment guidelines. Multivariable analysis showed increased white blood cell count at diagnosis (HR, 1.09; 95% CI, 1.04-1.14; p < 0.001), older age (HR, 1.15; 95% CI, 1.07-1.23; p < 0.001) and diabetic history (HR, 3.71; 95% CI, 1.27-10.78; p = 0.012) associated with greater mortality. Not receiving pharmacological treatment according to guidelines was also independently associated with increased mortality (HR, 3.12; 95% CI, 1.13-8.65; p = 0.029).

Benefit-risk profile of cytoreductive drugs along with antiplatelet and antithrombotic therapy after transient ischemic attack or ischemic stroke in myeloproliferative neoplasms

We analyzed 597 patients with myeloproliferative neoplasms (MPN) who presented transient ischemic attacks (TIA, n = 270) or ischemic stroke (IS, n = 327). Treatment included aspirin, oral anticoagulants, and cytoreductive drugs. The composite incidence of recurrent TIA and IS, acute myocardial infarction (AMI), and cardiovascular (CV) death was 4.21 and 19.2%, respectively at one and five years after the index event, an estimate unexpectedly lower than reported in the general population. Patients tended to replicate the first clinical manifestation (hazard ratio, HR: 2.41 and 4.41 for recurrent TIA and IS, respectively); additional factors for recurrent TIA were previous TIA (HR: 3.40) and microvascular disturbances (HR: 2.30); for recurrent IS arterial hypertension (HR: 4.24) and IS occurrence after MPN diagnosis (HR: 4.47). CV mortality was predicted by age over 60 years (HR: 3.98), an index IS (HR: 3.61), and the occurrence of index events after MPN diagnosis (HR: 2.62). Cytoreductive therapy was a strong protective factor (HR: 0.24). The rate of major bleeding was similar to the general population (0.90 per 100 patient-years). In conclusion, the long-term clinical outcome after TIA and IS in MPN appears even more favorable than in the general population, suggesting an advantageous benefit-risk profile of antithrombotic and cytoreductive treatment.

Risk Factors for and Management of MPN-Associated Bleeding and Thrombosis

PURPOSE OF THE REVIEW

The Philadelphia chromosome-negative myeloproliferative neoplasms (MPN) are characterized by both thrombotic and bleeding complications. The purpose of this review is to describe the risk factors associated with bleeding and thrombosis in MPN, as well as to review prevention strategies and management of these complications.

RECENT FINDINGS

Well-described risk factors for thrombotic complications include older age and history of prior thrombosis, along with traditional cardiovascular and venous thromboembolic risk factors. More recently, JAK2 V617F mutation has been found to carry an increased risk of thrombotic complications, whereas CALR has a lower risk than JAK2 mutation. Factors associated with an increased risk of bleeding in MPN include a prior history of bleeding, acquired von Willebrand syndrome, and primary myelofibrosis. Recent findings suggest that thrombocytosis carries a higher risk of bleeding than thrombosis in MPN, and aspirin may exacerbate this risk of bleeding, particularly in CALR-mutated ET. Much of the management of MPN focuses on predicting risk of bleeding and thrombosis and initiating prophylaxis to prevent complications in those at high risk of thrombosis. Emerging evidence suggests that sub-populations may have bleeding risk that outweighs thrombotic risk, particularly in setting of antiplatelet therapy. Future work is needed to better characterize this balance. At present, a thorough assessment of the risks of bleeding and thrombosis should be undertaken for each patient, and herein, we review risk factors for and management of these complications.

Prognostic risk model for patients with high-risk polycythemia vera and essential thrombocythemia

INTRODUCTION

Polycythemia Vera (PV) and Essential Thrombocythemia (ET) are the most frequent Philadelphia chromosome-negative myeloproliferative neoplasms, the other entity being myelofibrosis. Management of patients with PV and ET is fraught with difficulties as they have an inherent tendency to cause thrombotic and hemorrhagic events. There are no curative treatment options, therefore it is important that a risk-adapted treatment approach is applied. Areas covered: This review discusses existing literature about prognosis in PV and ET, and addresses critical aspects related to defining 'high-risk' disease. In addition to the traditional risk factors such as age and prior thrombotic history, we discuss the prognostic impact of additional parameters such as cardiovascular risk factors, white blood cell count, karyotype and gene mutations. Expert commentary: We use age>60 years, presence of JAK2 mutation and a prior thrombotic history as the principle determinants of 'high-risk' for thrombosis in PV and ET, dividing the patients into very-low, low, intermediate and high-risk disease. Typically, low-risk patients are treated either with observation or aspirin alone. High-risk patients require cytoreductive therapies, along with aspirin and/or systemic anticoagulation. Intermediate-risk patients are treated on a case-by-case basis. Further, we aim to maintain a hematocrit <45% with aggressive phlebotomy in patients with PV.

Essential thrombocythemia treatment algorithm 2018

Current drug therapy for myeloproliferative neoplasms, including essential thrombocythemia (ET) and polycythemia vera (PV), is neither curative nor has it been shown to prolong survival. Fortunately, prognosis in ET and PV is relatively good, with median survivals in younger patients estimated at 33 and 24 years, respectively. Therefore, when it comes to treatment in ET or PV, less is more and one should avoid exposing patients to new drugs that have not been shown to be disease-modifying, and whose long-term consequences are suspect (e.g., ruxolitinib). Furthermore, the main indication for treatment in ET and PV is to prevent thrombosis and, in that regard, none of the newer drugs have been shown to be superior to the time-tested older drugs (e.g., hydroxyurea). We currently consider three major risk factors for thrombosis (history of thrombosis, JAK2/MPL mutations, and advanced age), in order to group ET patients into four risk categories: "very low risk" (absence of all three risk factors); "low risk" (presence of JAK2/MPL mutations); "intermediate-risk" (presence of advanced age); and "high-risk" (presence of thrombosis history or presence of both JAK2/MPL mutations and advanced age). Herein, we provide a point-of-care treatment algorithm that is risk-adapted and based on evidence and decades of experience.

What are the current treatment approaches for patients with polycythemia vera and essential thrombocythemia?

Polycythemia vera (PV) and essential thrombocythemia (ET) are chronic myeloproliferative neoplasms that are characterized by thrombohemorrhagic complications, symptom burden, and impaired survival mainly due to thrombosis, progression to myelofibrosis, and transformation to acute leukemia. In this manuscript, we will review the most recent changes in diagnostic criteria, the improvements in risk stratification, and the "state of the art" in the daily management of these disorders. The role of conventional therapies and novel agents, interferon α and the JAK2 inhibitor ruxolitinib, is critically discussed based on the results of a few basic randomized clinical studies. Several unmet needs remain, above all, the lack of a curative approach that might overcome the still burdensome morbidity and mortality of these hematologic neoplasms, as well as the toxicities associated with therapeutic agents.

JAK-2 V617F mutation increases heparanase procoagulant activity

Patients with polycythaemia vera (PV), essential thrombocythaemia (ET) and primary myelofibrosis (PMF) are at increased risk of arterial and venous thrombosis. In patients with ET a positive correlation was observed between JAK-2 V617F mutation, that facilitates erythropoietin receptor signalling, and thrombotic events, although the mechanism involved is not clear. We previously demonstrated that heparanase protein forms a complex and enhances the activity of the blood coagulation initiator tissue factor (TF) which leads to increased factor Xa production and subsequent activation of the coagulation system. The present study was aimed to evaluate heparanase procoagulant activity in myeloproliferative neoplasms. Forty bone marrow biopsies of patients with ET, PV, PMF and chronic myelogenous leukaemia (CML) were immunostained to heparanase, TF and TF pathway inhibitor (TFPI). Erythropoietin receptor positive cell lines U87 human glioma and MCF-7 human breast carcinoma were studied. Heparanase and TFPI staining were more prominent in ET, PV and PMF compared to CML. The strongest staining was in JAK-2 positive ET biopsies. Heparanase level and procoagulant activity were higher in U87 cells transfected to over express JAK-2 V617F mutation compared to control and the effect was reversed using JAK-2 inhibitors (Ruxolitinib, VZ3) and hydroxyurea, although the latter drug did not inhibit JAK-2 phosphorylation. Erythropoietin increased while JAK-2 inhibitors decreased the heparanase level and procoagulant activity in U87 and MCF-7 parental cells. In conclusion, JAK-2 is involved in heparanase up-regulation via the erythropoietin receptor. The present findings may potentially point to a new mechanism of thrombosis in JAK-2 positive ET patients.

Fibrotic Lung Toxicity Induced by Hydroxycarbamide

A patient treated for 4 months with hydroxycarbamide (hydroxyurea) for chronic myelomonocytic leukemia was admitted to hospital for recently developed severe dyspnea and acute respiratory failure. The computed tomographic scan of the chest showed diffuse ground glass opacities, some centrilobular low-density nodules (resembling hypersensitivity pneumonitis-like pattern), and minimal interstitial reticulation of the subpleural region. The analysis of bronchoalveolar lavage fluid excluded infection, as did serological examinations. The patient was started on oxygen therapy and with relief of thrombocytopenia and suspected hemolytic anemia, hydroxyurea treatment was discontinued. The patient underwent steroid therapy, with a rapid progressive improvement of clinical and radiological features. As hydroxyurea is increasingly used for a number of systemic disorders, physicians must be aware of its potential lung toxicity, requiring immediate cessation of the treatment and empiric corticosteroid therapy.

Therapeutic options for leukemic transformation in patients with myeloproliferative neoplasms

Approximately 5-10% of patients with Philadelphia chromosome negative myeloproliferative neoplasms (MPN) comprising of essential thrombocythemia, polycythemia vera and primary myelofibrosis) experience transformation to acute myeloid leukemia (AML, ≥20% blasts). Treatment options for post-MPN AML patients are limited, as conventional approaches like standard chemotherapy, fail to offer long-term benefit. Median survival for secondary AML is ∼2.4 months. Post-MPN AML therefore represents an area of urgent clinical need. At present, allogeneic stem cell transplant (ASCT) following induction therapy is the best therapeutic option. Patients ineligible for ASCT are treated with hypomethylating agents. New agents under investigation include histone deacetylase inhibitors, JAKinhibitors and agents targeting the BRD4 protein. Combined treatment strategies involving these novel agents are being tested. In this review we present the current evidence regarding treatment options for post-MPN AML patients.

Treatment of essential thrombocythemia in Europe: a prospective long-term observational study of 3649 high-risk patients in the Evaluation of Anagrelide Efficacy and Long-term Safety study

Evaluation of Anagrelide (Xagrid^®) Efficacy and Long-term Safety, a phase IV, prospective, non-interventional study performed in 13 European countries enrolled high-risk essential thrombocythemia patients treated with cytoreductive therapy. The primary objectives were safety and pregnancy outcomes. Of 3721 registered patients, 3649 received cytoreductive therapy. At registration, 3611 were receiving: anagrelide (Xagrid^®) (n=804), other cytoreductive therapy (n=2666), or anagrelide + other cytoreductive therapy (n=141). The median age was 56 vs. 70 years for anagrelide vs. other cytoreductive therapy. Event rates (patients with events/100 patient-years) were 1.62 vs. 2.06 for total thrombosis and 0.15 vs. 0.53 for venous thrombosis. Anagrelide was more commonly associated with hemorrhage (0.89 vs. 0.43), especially with anti-aggregatory therapy (1.35 vs. 0.33) and myelofibrosis (1.04 vs. 0.30). Other cytoreductive therapies were more associated with acute leukemia (0.28 vs. 0.07) and other malignancies (1.29 vs. 0.44). Post hoc multivariate analyses identified increased risk for thrombosis with prior thrombohemorrhagic events, age ≥65, cardiovascular risk factors, or hypertension. Risk factors for transformation were prior thrombohemorrhagic events, age ≥65, time since diagnosis, and platelet count increase. Safety analysis reflected published data, and no new safety concerns for anagrelide were found. Live births occurred in 41/54 pregnancies (76%). clinicaltrials.gov Identifier: 00567502.

Management of venous thromboembolism in myeloproliferative neoplasms

PURPOSE OF REVIEW

Venous thromboembolism is frequent in chronic myeloproliferative neoplasms (MPN). The current strategy for its management includes cytoreductive therapy and antithrombotic prophylaxis, but many issues remain uncertain. In this review, the risk factors and prevention of recurrences will be discussed.

RECENT FINDINGS

Around one-third of patients with polycythemia vera and essential thrombocythemia experience a major thrombosis at diagnosis or during follow-up. According to the European Leukemia Net guidelines, these patients must be included in the high-risk group for thrombotic recurrence and should be treated with cytoreduction and antiplatelet or anticoagulant drugs in the presence of arterial or venous thrombosis, respectively. Despite this treatment, the annual incidence of recurrence after the first venous thrombosis varies from 4.2 to 6.5% on vitamin K-antagonists and is doubled after discontinuation. The highest incidence of recurrence occurs after cerebral and hepatic vein thrombosis (8.8 and 8 per 100 pt-years, respectively). The occurrence of major bleeding on vitamin K-antagonists is similar to a non-MPN population and accounts for a rate of 1.8-2.4 per 100 pt-years.

SUMMARY

After venous thrombosis, the incidence of recurrence in MPN remains elevated, which suggested there was a need to review the current recommendations of primary and secondary prophylaxis.

The Use of Anagrelide in Myeloproliferative Neoplasms, with Focus on Essential Thrombocythemia

Anagrelide (ANA) is a drug with specific platelet-lowering activity, used primarily in ET, registered as a second-line drug in essential thrombocythemia (ET) in Europe and in some countries as first-line therapy, in USA licensed by FDA for thrombocythemia in myeloproliferative neoplasms (MPN). The platelet-lowering efficacy is similar to that of hydroxycarbamide (HC), around 70 % complete response and 90 % partial response. Side effects are common, especially headache and tachycardia, but usually subside or disappear within a few weeks. Around 20 % of patients stop ANA therapy due to side effects or insufficient response. Studies of treatment patterns in Europe show that ANA is preferentially given to younger patients, probably because of the concern for a possible leukemogenic effect of the common first-line drug, HC. Only two randomized studies have compared the efficacy of ANA and HC in preventing thrombosis and haemorrhage, the larger of them showing a slightly better efficacy of HC, the other showing non-inferiority of ANA to HC. A recent observational 5-year study of 3600 patients shows a low and basically similar efficacy of ANA and other cytoreductive therapies in ET. ANA does not appear to inhibit fibrosis development, and probably due to its anticoagulation properties, the combination of ASA and ANA produces an increased rate of haemorrhage. Combination of ANA with HC or interferon (IFN) is feasible and effective in patients with insufficient platelet response to mono-therapy.

An Exercise in Extrapolation: Clinical Management of Atypical CML, MDS/MPN-Unclassifiable, and MDS/MPN-RS-T

According to the recently published 2016 World Health Organization (WHO) classification of myeloid malignancies, myelodysplastic/myeloproliferative neoplasms (MDS/MPN) include atypical chronic myeloid leukemia (aCML), MDS/MPN-unclassifiable (MDS/MPN-U), chronic myelomonocytic leukemia (CMML), juvenile myelomonocytic leukemia (JMML), and MDS/MPN ring sideroblasts with thrombocytosis (MDS/MPN-RS-T). MDS/MPN-RS-T was previously a provisional category known as refractory anemia with ring sideroblasts with thrombocytosis (RARS-T) which has now attained a distinct designation in the 2016 WHO classification. In this review, we focus on biology and management of aCML, MDS/MPN-U, and MDS/MPN-RS-T. There is considerable overlap between these entities which we attempt to further elucidate in this review. We also discuss recent advances in the field of molecular landscape that further defines and characterizes this heterogeneous group of disorders. The paucity of clinical trials available secondary to unclear pathogenesis and rarity of these diseases makes the management of these entities clinically challenging. This review summarizes some of the current knowledge of the molecular pathogenesis and suggested treatment guidelines based on the available data.

The Treatment Landscape of Myelofibrosis Before and After Ruxolitinib Approval

INTRODUCTION/BACKGROUND

Myelofibrosis (MF) is a chronic myeloproliferative neoplasm that presents with a heterogeneous clinical phenotype and prognosis. Before the US Food and Drug Administration approval of ruxolitinib, treatment options were varied and had limited effect. The increased use of ruxolitinib has drastically altered the MF treatment landscape. In this study, we aimed to clarify the clinical situations in which ruxolitinib is being used and analyze its effect on this landscape.

PATIENTS AND METHODS

We retrospectively assessed treatment choices for MF patients treated at our institution (n = 309). This population was divided into 2 cohorts on the basis of a diagnosis before (cohort BR: n = 174) or after (cohort AR: n = 135) ruxolitinib approval. Cohorts were further stratified for comparison according to presenting clinical factors.

RESULTS

Expectedly, the first-line use of ruxolitinib markedly increased after its approval. AR patients were less likely to receive erythropoiesis-stimulating agents (ESAs; P = .0003) and thalidomide (P = .003) than BR patients. In patients with MF-related symptoms and/or splenomegaly, increased use of ruxolitinib was associated with decreased use of first-line ESA (P = .03) or thalidomide (P = .03). In anemic patients, increased use of first-line ruxolitinib was associated with a decreased use of thalidomide (P = .007). In patients with severe leukocytosis, ruxolitinib use did not significantly increase and hydroxyurea was the preferred first-line agent.

CONCLUSION

Overall, the increased use of ruxolitinib appears to have come predominantly at the expense of thalidomide and ESAs, while not having a large effect on the first-line use of hydroxyurea.

High platelet count at diagnosis is a protective factor for thrombosis in patients with essential thrombocythemia

To assess the role of platelet (PLT) count for thrombotic complications in Essential Thrombocythemia (ET), 1201 patients followed in 11 Hematological centers in the Latium region were retrospectively evaluated. At multivariate analysis, the following factors at diagnosis were predictive for a worse Thrombosis-free Survival (TFS): the occurrence of previous thrombotic events (p=0.0004), age>60years (p=0.0044), spleen enlargement (p=0.042) and a lower PLT count (p=0.03). Receiver Operating Characteristic (ROC) analyses based on thrombotic events during follow-up identified a baseline platelet count of 944×10⁹/l as the best predictive threshold: thrombotic events were 40/384 (10.4%) in patients with PLT count >944×10⁹/l and 109/817 (13.3%) in patients with PLT count <944×10⁹/l, respectively (p=0.04). Patients with PLT count <944×10⁹/l were older (median age 60.4years. vs 57.1years., p=0.016), had a lower median WBC count (8.8×10⁹/l vs 10.6×10⁹/l, p<0.0001), a higher median Hb level (14.1g/dl vs 13.6g/dl, p<0.0001) and a higher rate of JAK-2-V617F positivity (67.2% vs 41.6%, p<0.0001); no difference was observed as to thrombotic events before diagnosis, spleen enlargement and concomitant Cardiovascular Risk Factors. In conclusion, our results confirm the protective role for thrombosis of an high PLT count at diagnosis. The older age and the higher rate of JAK-2 V617F positivity in the group of patients with a baseline lower PLT count could in part be responsible of this counterintuitive finding.

Role of treatment on the development of secondary malignancies in patients with essential thrombocythemia

Aim of this study is to explore the role of different treatments on the development of secondary malignancies (SMs) in a large cohort of essential thrombocythemia (ET) patients. We report the experience of a regional cooperative group in a real‐life cohort of 1026 patients with ET. We divided our population into five different groups: group 0, no treatment; group 1, hydroxyurea (HU); group 2, alkylating agents (ALK); group 3, ALK + HU sequentially or in combination; and group 4, anagrelide (ANA) and/or α‐interferon (IFN) only. Patients from groups 1, 2, and 3 could also have been treated either with ANA and/or IFN in their medical history, considering these drugs not to have an additional cytotoxic potential. In all, 63 of the 1026 patients (6%) developed 64 SM during the follow‐up, after a median time of 50 months (range: 2–158) from diagnosis. In univariate analysis, a statistically significant difference was found only for gender (P = 0.035) and age (P = 0.0001). In multivariate analysis, a statistically significant difference was maintained for both gender and age (gender HR1.7 [CI 95% 1.037–2.818] P = 0.035; age HR 4.190 [CI 95% 2.308–7.607] P = 0.0001). The impact of different treatments on SMs development was not statistically significant. In our series of 1026 ET patients, diagnosed and followed during a 30‐year period, the different therapies administered, comprising HU and ALK, do not appear to have impacted on the development of SM. A similar rate of SMs was observed also in untreated patients. The only two variables which showed a statistical significance were male gender and age >60 years.

Polycythemia and Thrombocytosis

Myeloproliferative neoplasms (MPNs) are diseases of excess cell proliferation from bone marrow precursors. Two classic MPNs, polycythemia vera (PV) and essential thrombocytosis (ET), are conditions of excess proliferation of red blood cells and platelets, respectively. Although PV and ET involve different cells in the myeloid lineage, their clinical presentations have shared features, consistent with overlapping mutations in growth factor signaling. The management of both diseases involves minimizing the risk of thrombotic and hemorrhagic complications. Both PV and ET can progress to myelofibrosis or acute myeloid leukemia, portending a poor prognosis. MPNs can also present as primary myelofibrosis.

The role of thrombocytapheresis in the contemporary management of hyperthrombocytosis in myeloproliferative neoplasms: A case-based review

Extreme thrombocytosis induces an acquired thrombotic-hemorrhagic diathesis, and left uncontrolled is a harbinger of potentially fatal vascular complications. Currently, cytoreduction with medical therapy remains the mainstay of hyperthrombocytosis management. However, it offers a less-than-ideal option in situations where a rapid reduction in platelets is urgently needed, as in the presence of vital end-organ ischemia or to ameliorate of life-threatening hemorrhage. The role of thrombocytapheresis, or plateletpheresis, in hyperthrombocytosis has become increasingly obsolete given the proactive titration of cytoreductive therapies and early identification and correction of reversible causes of reactive thrombocytosis. Despite its narrowed indications, plateletpheresis continues to offer a valuable temporizing measure in platelet count reduction before cytoreductive agents exert their maximal effect. In this context, it is important for the treating physician to be aware of the symptoms and risks associated with hyperthrombocytosis to inform best clinical practices. In this review, we discuss the role of plateletpheresis in the modern-day management of hyperthrombocytosis in patients with myeloproliferative neoplasms through a case based review of the literature. It becomes apparent throughout the discussion that the decision to perform plateletpheresis should be individualized based upon the clinical scenario, degree of thrombocytosis, available infrastructure and every patient's risk profile.

Refractory anemia with ring sideroblasts (RARS) and RARS with thrombocytosis (RARS-T): 2017 update on diagnosis, risk-stratification, and management

DISEASE OVERVIEW

Ring sideroblasts (RS) are erythroid precursors with abnormal perinuclear mitochondrial iron accumulation. Two myeloid neoplasms defined by the presence of RS, include refractory anemia with ring sideroblasts (RARS), now classified under myelodysplastic syndromes with RS (MDS-RS) and RARS with thrombocytosis (RARS-T); now called myelodysplastic/myeloproliferative neoplasm with RS and thrombocytosis (MDS/MPN-RS-T).

DIAGNOSIS

MDS-RS is a lower risk MDS, with single or multilineage dysplasia (SLD/MLD), <5% bone marrow (BM) blasts and ≥15% BM RS (≥5% in the presence of SF3B1 mutations). MDS/MPN-RS-T, now a formal entity in the MDS/MPN overlap syndromes, has diagnostic features of MDS-RS-SLD, along with a platelet count ≥ 450 × 10(9)/L and large atypical megakaryocytes (similar to BCR-ABL1 negative MPN).

MUTATIONS AND KARYOTYPE

Mutations in SF3B1 are seen in ≥80% of patients with MDS-RS-SLD and MDS/MPN-RS-T, and strongly correlate with the presence of BM RS; MDS/MPN-RS-T patients also demonstrate JAK2V617F, ASXL1, DNMT3A, SETBP1, and TET2 mutations; with ASXL1/SETBP1 mutations adversely impacting survival. Cytogenetic abnormalities are uncommon in both diseases.

RISK STRATIFICATION

Most patients with MDS-RS-SLD are stratified into lower risk groups by the revised-International Prognostic Scoring System (R-IPSS). Disease outcome in MDS/MPN-RS-T is better than that of MDS-RS-SLD, but worse than that of essential thrombocythemia. Both diseases have a low risk of leukemic TREATMENT: Anemia and iron overload are complications seen in both and are managed similar to lower risk MDS and MPN. Aspirin therapy is reasonable in MDS/MPN-RS-T, especially in the presence of JAK2V617F, but the value of platelet-lowering drugs is uncertain.

Hydroxycarbamine: from an Old Drug Used in Malignant Hemopathies to a Current Standard in Sickle Cell Disease

While hydroxycarbamide (hydroxyurea, HU) has less and fewer indications in malignant hemopathies, it represents the only widely used drug which modifies sickle cell disease pathogenesis. Clinical experience with HU for patients with sickle cell disease has been accumulated over the past 25 years in Western countries. The review of the literature provides increasing support for safety and efficacy in both children and adults for reducing acute vaso-occlusive events including pain episodes and acute chest syndrome. No increased incidence of leukemia and teratogenicity was demonstrated. HU has become the standard-of-care for sickle cell anemia but remains underused. Barriers to its use should be identified and overcome.

Polycythemia vera and essential thrombocythemia: 2017 update on diagnosis, risk-stratification, and management

DISEASE OVERVIEW

Polycythemia Vera (PV) and essential thrombocythemia (ET) are myeloproliferative neoplasms respectively characterized by erythrocytosis and thrombocytosis; other disease features include leukocytosis, splenomegaly, thrombosis, bleeding, microcirculatory symptoms, pruritus, and risk of leukemic or fibrotic transformation.

DIAGNOSIS

PV is defined by a JAK2 mutation, whose absence, combined with normal or increased serum erythropoietin level, makes the diagnosis unlikely. JAK2, CALR, and MPL mutations are the mutually exclusive "driver" mutations in ET with respective incidences of 55%, 25%, and 3%; approximately 17% are triple-negative. However, the same molecular markers might also be present in prefibrotic myelofibrosis, whose morphological distinction from ET is prognostically relevant.

SURVIVAL AND LEUKEMIC/FIBROTIC TRANSFORMATION

Median survivals are approximately 14 years for PV and 20 years for ET; the corresponding values for younger patients (age <60 years) are 24 and 33 years. Life-expectancy in ET is inferior to the control population. Driver mutational status has not been shown to affect survival in ET whereas the presence of JAK2/MPL mutations has been associated with higher risk of arterial thrombosis and that of MPL with higher risk of fibrotic progression. Risk factors for overall survival in both ET and PV include advanced age, leukocytosis and thrombosis. Leukemic transformation rates at 20 years are estimated at <10% for PV and 5% for ET; fibrotic transformation rates are slightly higher. Most recently, ASXL1, SRSF2, and IDH2 mutations have been associated with inferior overall, leukemia-free or fibrosis-free survival in PV; similarly adverse mutations in ET included SH2B3, SF3B1, U2AF1, TP53, IDH2, and EZH2.

THROMBOSIS RISK STRATIFICATION

Current risk stratification in PV and ET is designed to estimate the likelihood of recurrent thrombosis. Accordingly, PV includes two risk categories: high-risk (age >60 years or thrombosis history) and low-risk (absence of both risk factors). In ET, risk stratification includes four categories: very low risk (age ≤60 years, no thrombosis history, JAK2/MPL un-mutated), low risk (age ≤60 years, no thrombosis history, JAK2/MPL mutated), intermediate risk (age >60 years, no thrombosis history, JAK2/MPL un-mutated), and high risk (thrombosis history or age >60 years with JAK2/MPL mutation). In addition, presence of extreme thrombocytosis (platelets >1000 × 10(9)/L) might be associated with acquired von Willebrand syndrome (AvWS) and, therefore, risk of bleeding.

RISK-ADAPTED THERAPY

The main goal of therapy in PV and ET is to prevent thrombohemorrhagic complications. All patients with PV require phlebotomy to keep hematocrit below 45% and once-daily aspirin (81 mg). In addition, high-risk patients with PV require cytoreductive therapy. Very low risk ET patients might not require any form of therapy while low-risk patients require at least once-daily aspirin therapy. Cytoreductive therapy is also recommended for high-risk ET patients but it is not mandatory for intermediate-risk patients. First-line drug of choice for cytoreductive therapy, in both ET and PV, is hydroxyurea and second-line drugs of choice are interferon-α and busulfan. We currently do not recommend treatment with ruxolutinib or other JAK2 inhibitors in PV or ET, unless in the presence of severe and protracted pruritus or marked splenomegaly that is not responding to the aforementioned drugs. Screening for AvWS is recommended before administrating aspirin, in the presence of extreme thrombocytosis. Am. J. Hematol. 92:95-108, 2017. © 2016 Wiley Periodicals, Inc.

Pulmonary vein thrombosis in a patient with polycythemia vera

Pulmonary vein thrombosis (PVT) is a rarely encountered disease entity with varied clinical presentations. It is usually associated with lung carcinoma, lung surgeries and as a complication of the radiofrequency catheter ablation procedure for atrial fibrillation. Its clinical manifestations can vary from mild hemoptysis to lung infarction with hemodynamic compromise. A 76-year-old male presented with a 2-d history of pleuritic left sided chest pain. His past medical history included polycythemia vera, atrial fibrillation, coronary artery disease, pulmonary embolism and pulmonary hypertension. Chest radiograph was normal, troponins were normal and the 12-lead electrocardiogram did not show any ischemic changes. A computerized tomography pulmonary angiogram revealed a filling defect in the left lower lobe pulmonary vein. He was treated with subcutaneous enoxaparin and his symptoms improved. This case highlights a rare etiology of chest pain and the first reported case of the association of polycythemia vera and pulmonary vein thrombosis. A high index of suspicion is required for appropriate diagnostic work up. PVT can mimic pulmonary embolism. The diagnostic work up and treatment strategies depend on acuity of presentation.

How I treat essential thrombocythemia

Essential thrombocythemia (ET) is an indolent myeloproliferative neoplasm that may be complicated by vascular events, including both thrombosis and bleeding. This disorder may also transform into more aggressive myeloid neoplasms, in particular into myelofibrosis. The identification of somatic mutations of JAK2, CALR, or MPL, found in about 90% of patients, has considerably improved the diagnostic approach to this disorder. Genomic profiling also holds the potential to improve prognostication and, more generally, clinical decision-making because the different driver mutations are associated with distinct clinical features. Prevention of vascular events has been so far the main objective of therapy, and continues to be extremely important in the management of patients with ET. Low-dose aspirin and cytoreductive drugs can be administered to this purpose, with cytoreductive treatment being primarily given to patients at high risk of vascular complications. Currently used cytoreductive drugs include hydroxyurea, mainly used in older patients, and interferon α, primarily given to younger patients. There is a need for disease-modifying drugs that can eradicate clonal hematopoiesis and/or prevent progression to more aggressive myeloid neoplasms, especially in younger patients. In this article, we use a case-based discussion format to illustrate our approach to diagnosis and treatment of ET.

Coexisting Cardiac and Hematologic Disorders

Patients with concomitant cardiac and hematologic disorders presenting for noncardiac surgery are challenging. Anemic patients with cardiac disease should be approached in a methodical fashion. Transfusion triggers and target should be based on underlying symptomatology. The approach to anticoagulation management in patients with artificial heart valves, cardiac devices, or severe heart failure in the operative setting must encompass a complete understanding of the rationale of a patient's therapy as well as calculate the risk of changing this regimen. This article focuses common disorders and discusses strategies to optimize care in patients with coexisting cardiac and hematologic disease.

Ruxolitinib in the treatment of polycythemia vera: patient selection and special considerations

The discovery of JAK2 V617F mutation in the mid-2000s started to fill the gap between clinical presentation of polycythemia vera (PV), first described by Vaquez at the end of the 19th century, and spontaneous erythroid colony formation, reported by Prchal and Axelrad in the mid-1970s. The knowledge on this mutation brought an important insight to our understanding of PV pathogenesis and led to a revision of the World Health Organization diagnostic criteria in 2008. JAK-STAT is a major signaling pathway implicated in survival and proliferation of hematopoietic precursors. High prevalence of JAK2 V617F mutation among myeloproliferative neoplasms (>95% in PV and ~50% in primary myelofibrosis and essential thrombocythemia) together with its role in constitutively activating JAK-STAT made JAK2 a privileged therapeutic target. Ruxolitinib, a JAK 1 and 2 inhibitor, has already proven to be efficient in relieving symptoms in primary myelofibrosis and PV. In the latter, it also appears to improve microvascular involvement. However, evidence regarding its potential role in altering the natural course of PV and its use as an adjunct to current standard therapies is sparse. Therapeutic advances are needed in PV as phlebotomy, low-dose aspirin, cytoreductive agents, and interferon alpha are the only therapeutic tools available at the moment to influence outcome. Even though several questions are still unanswered, this review aims to serve as an overview article of the potential role of ruxolitinib in PV according to current literature and expert opinion. It should help hematologists to visualize the place of this tyrosine kinase inhibitor in the field of current practice and offer criteria for a careful patient selection.

Second malignancies in hydroxyurea and interferon-treated Philadelphia-negative myeloproliferative neoplasms

OBJECTIVE

In an era of controversy in regard to 'hydroxyurea-leukaemogenicity' and when interferon-alfa2 (IFN) is being revived in the treatment of Philadelphia-negative myeloproliferative neoplasms (MPNs), we aim in this single-centre observational study to describe the frequencies of second malignancies in a cohort of MPN patients treated with hydroxyurea (HU) or IFN monotherapy or the combination of these agents.

PATIENTS AND METHODS

Records of a MPN cohort of 196 patients were reviewed, and a retrospective analysis was performed on 90 patients treated with HU, 38 patients treated with IFN and 68 patients treated with both IFN and HU. Logistic regression was used to compare frequencies in second malignancies.

RESULTS

Patients treated with HU had a significantly higher risk of developing all second malignancies compared with patients treated with IFN [HU vs. IFN: OR of 4.01 (95%CI: 1.12-14.27, P-value: 0.023) and HU-IFN vs. IFN: OR 5.58 (95%CI: 1.55-20.15, P-value: 0.004)].

CONCLUSION

We have found an increased risk of second malignancies in MPN patients treated with HU compared with patients treated with IFN.

How to Treat Essential Thrombocythemia and Polycythemia Vera

Polycythemia vera and essential thrombocythemia (ET) are chronic myeloproliferative neoplasms associated with thrombotic or hemorrhagic complications, and increased risk of transformation to myelofibrosis and acute myeloid leukemia. The main goal of therapy is aimed at preventing vascular events that are the leading cause of morbidity and mortality in these patients. Accordingly, risk stratification is the basis for deciding when to treat a patient with cytoreductive therapy. The European LeukemiaNet has developed a series of management recommendations for front-line and second-line therapy to provide the optimal treatment for the individual patient. There is still controversy about the efficacy and safety of several modalities of cytoreductive treatment in the long-term for both diseases and in the use of antiplatelet therapy in ET. The presence of JAK2V617F and CALR mutations in patients with ET has been related to different thrombotic risks, and this will probably lead to different therapeutic approaches in the near future. On the other hand, the near normal life expectancy of these patients makes a careful analysis of the benefits and risks associated with treatment essential. This review provides our current management strategy of patients with polycythemia vera and ET.

Group 5 Pulmonary Hypertension: The Orphan's Orphan Disease

Pulmonary hypertension is a complex disorder with multiple etiologies; the World Health Organization classification system divides pulmonary hypertension patients into 5 groups based on the underlying cause and mechanism. Group 5 pulmonary hypertension is a heterogeneous group of diseases that encompasses pulmonary hypertension secondary to multifactorial mechanisms. For many of the diseases, the true incidence, etiology, and treatment remain uncertain. This article reviews the epidemiology, pathogenesis, and management of many of the group 5 pulmonary hypertension disease states.

Is JAK2V617F Mutation the Only Factor for Thrombosis in Philadelphia-Negative Chronic Myeloproliferative Neoplasms?

The most common genetic disorder in Philadelphia negative chronic myeloproliferative neoplasms is the JAK2-V617F mutation. In the present study, we aimed to determine risk factors for thrombosis in patients with essential thrombocytosis and polycythemia vera. We screened the medical records of 101 patients. Risk factors which may predict thrombosis were recorded. Venous thrombosis (VT) before diagnosis was significantly higher in JAK2 positive patients. VT after diagnosis was similar in JAK2 positive and negative groups, and was significantly higher in elderly patients. Treatment places importance on the JAK2 mutation under unmodifiable cardiovascular risk factors such as advanced age after diagnosis.

Do we need antiplatelet therapy in thrombocytosis? Contra. Proposal for an individualized risk-adapted treatment

Thrombocytosis is a frequent laboratory finding but not a diagnosis. Therefore, elevated platelet counts (>450 x 10⁹/l) require careful diagnostic work-up to differentiate between reactive thrombocytosis (RT), caused by various conditions, and essential thrombocythemia (ET), a myeloproliferative neoplasm (MPN). In either setting, aspirin is widely used in clinical practice. However, RT (even at platelet counts >1000 x 10⁹/l) has never been shown to cause thrombosis or bleeding due to acquired von Willebrand factor defects in association with high platelet counts. Identification of reactive conditions and appropriate therapy of the underlying disorder are most relevant. By contrast to RT, ET and related MPN can be associated with thrombosis and/or hemorrhage. Current recommendations suggest the use of low-dose aspirin in all patients with ET unless contraindicated. However, the strength of this recommendation is weak, i. e. evidence level IIb grade B. A potential benefit of aspirin used for primary thromboprophylaxis in ET is mostly derived from the ECLAP study in polycythemia vera (PV). However, translating study results from PV to ET appears to be highly questionable and may be biased. In the absence of robust data regarding the benefit-risk balance of aspirin in ET, it appears reasonable (1) to stratify patients according to their individual thrombotic and bleeding risk, (2) to restrict the use of aspirin to high-risk categories and patients with microcirculatory disturbances, (3) to test for pharmacological efficacy (COX-1 inhibition; measurement of TXB₂), and (4) to modify the aspirin dosing regimen (twice instead of once daily) if required.

Anagrelide compared with hydroxyurea in essential thrombocythemia: a meta-analysis

Cytoreductive therapy, with or without low-dose aspirin, is the mainstay of thrombotic risk reduction in patients with essential thrombocythemia (ET), but the optimal choice of agent remains unclear. The aim of this study was to meta-analyze currently available data comparing anagrelide to hydroxyurea for reduction of rates of thrombosis, bleeding and death among patients with ET. A literature search for randomized, controlled trials comparing anagrelide to hydroxyurea among patients with ET revealed two published studies. Statistical analysis was performed using fixed effects meta-analysis. Rates of thrombosis were similar between patients treated with hydroxyurea vs anagrelide (RR 0.86, 95 % CI 0.64-1.16). Rates of major bleeding were lower in patients treated with hydroxyurea (RR 0.37, 95 % CI 0.18-0.75). Rates of progression to acute myeloid leukemia were not statistically different (RR 1.50, 95 % CI 0.43-5.29). The composite of thrombosis, major bleeding and death favored hydroxyurea (RR 0.78, 95 % CI 0.63-0.97). In conclusion, our analysis supports use of hydroxyurea as a first-line cytoreductive agent for patients with ET, based largely on decreased rates of major bleeding. Anagrelide appears to be equally effective for protection against thrombotic events and may be an appropriate alternative for patients who are intolerant of hydroxyurea.