Cardiovascular events and intensity of treatment in polycythemia vera

BACKGROUND

Current treatment recommendations for patients with polycythemia vera call for maintaining a hematocrit of less than 45%, but this therapeutic strategy has not been tested in a randomized clinical trial.

METHODS

We randomly assigned 365 adults with JAK2-positive polycythemia vera who were being treated with phlebotomy, hydroxyurea, or both to receive either more intensive treatment (target hematocrit, <45%) (low-hematocrit group) or less intensive treatment (target hematocrit, 45 to 50%) (high-hematocrit group). The primary composite end point was the time until death from cardiovascular causes or major thrombotic events. The secondary end points were cardiovascular events, cardiovascular hospitalizations, incidence of cancer, progression to myelofibrosis, myelodysplasia or leukemic transformation, and hemorrhage. An intention-to-treat analysis was performed.

RESULTS

After a median follow-up of 31 months, the primary end point was recorded in 5 of 182 patients in the low-hematocrit group (2.7%) and 18 of 183 patients in the high-hematocrit group (9.8%) (hazard ratio in the high-hematocrit group, 3.91; 95% confidence interval [CI], 1.45 to 10.53; P=0.007). The primary end point plus superficial-vein thrombosis occurred in 4.4% of patients in the low-hematocrit group, as compared with 10.9% in the high-hematocrit group (hazard ratio, 2.69; 95% CI, 1.19 to 6.12; P=0.02). Progression to myelofibrosis, myelodysplasia or leukemic transformation, and bleeding were observed in 6, 2, and 2 patients, respectively, in the low-hematocrit group, as compared with 2, 1, and 5 patients, respectively, in the high-hematocrit group. There was no significant between-group difference in the rate of adverse events.

CONCLUSIONS

In patients with polycythemia vera, those with a hematocrit target of less than 45% had a significantly lower rate of cardiovascular death and major thrombosis than did those with a hematocrit target of 45 to 50%. (Funded by the Italian Medicines Agency and others; ClinicalTrials.gov number, NCT01645124, and EudraCT number, 2007-006694-91.).

Quantitative risk assessment of verocytotoxin-producing Escherichia coli O157 and Campylobacter jejuni related to consumption of raw milk in a province in Northern Italy

A quantitative risk assessment was developed to describe the risk of campylobacteriosis and hemolytic uremic syndrome (HUS) linked to consumption of raw milk sold in vending machines in Northern Italy. Exposure assessment considered the microbiological status of dairy farms, expected milk contamination, storage conditions from bulk tank to home storage, microbial growth during storage, destruction experiments, consumption frequency of raw milk, age of consumers, serving size, and consumption preference. The differential risk between milk handled under regulation conditions (4°C throughout all phases) and the worst field handling conditions was considered. The probability of Campylobacter jejuni infection was modeled with a single-hit dose-response beta-Poisson model, whereas for HUS an exponential dose-response model was chosen and two probabilities were used to model the higher susceptibility of children younger than 5 years old. For every 10,000 to 20,000 consumers each year, the models predicted for the best and worst storage conditions, respectively, 2.12 and 1.14 campylobacteriosis cases and 0.02 and 0.09 HUS cases in the 0- to 5-year age group and 0.1 and 0.5 HUS cases in the >5-year age group. The expected pediatric HUS cases do not differ considerably from those reported in Italy by the Minister of Health. The model developed may be a useful tool for extending the assessment of the risk of campylobacteriosis and HUS due to raw milk consumption at the national level in Italy. Considering the epidemiological implications of this study, the risk of illness linked to raw milk consumption should not be ignored and could be reduced by the use of simple measures. Boiling milk before consumption and strict control of temperatures by farmers during raw milk distribution have significant effects on campylobacteriosis and HUS and are essential measures for risk management.

Management of special conditions in patients on vitamin K antagonists

Physicians are occasionally faced with difficult situations in the management of vitamin K antagonists (VKA) due to the lack of sound data available in controlled studies on certain conditions. In this review we would like to address some special but frequent conditions that can be encountered in daily clinical practice. These include the use of VKA in hemodialysis, thromboembolism in patients with liver cirrhosis and the thromboembolic risk in patients who bleed in the course of treatment with VKA. Moreover, two other conditions were examined: what the best way of expressing prothrombin time would be in patients with liver disease and how to behave when a patient treated with VKA shows a subtherapeutic INR. These topics were discussed by a panel of experts during a workshop recently held in Milan by the Italian Federation of Centres for the Diagnosis of Thrombosis and the Surveillance of Antithrombotic Therapies (FCSA). The main aim of the workshop was to provide helpful and practical advice to physicians in the daily management of VKA.

Phase III studies on novel oral anticoagulants for stroke prevention in atrial fibrillation: a look beyond the excellent results

In this overview we address the three phase III studies that compared new oral anticoagulants (dabigatran, rivaroxaban and apixaban) with warfarin in the setting of stroke prevention in atrial fibrillation. Strengths and weaknesses of the studies were examined in detail through indirect comparison. We analyze and comment the inclusion and exclusion criteria, the characteristics of randomized patients, the primary efficacy and safety end points and side effects. All new oral anticoagulants resulted in being non-inferior to vitamin K antagonists in reducing stroke or systemic embolism in patients with atrial fibrillation. Dabigatran 150 mg and apixaban were superior to vitamin K antagonists. Importantly, new oral anticoagulants significantly reduced hemorrhagic stroke in all three studies. Major differences among new oral anticoagulants include the way they are eliminated and side effects. Both dabigatran and apixaban were tested in low- to moderate-risk patients (mean CHADS2 [Congestive heart failure, Hypertension, Age, Diabetes, Stroke] score = 2.1-2.2) whereas rivaroxaban was tested in high-risk patients (mean CHADS2 score = 3.48) and at variance with dabigatran and apixaban was administered once daily. Apixaban significantly reduced mortality from any cause. The choice of a new oral anticoagulant should take into account these and other differences between the new drugs.

Leukocytosis as an important risk factor for arterial thrombosis in WHO-defined early/prefibrotic myelofibrosis: an international study of 264 patients

We aimed to determine risk factors for thrombotic events in early/prefibrotic myelofibrosis diagnosed according to the World Health Organization criteria. Multivariate Cox regression analysis was calculated on a total number of 264 patients derived from an international database. After a median follow-up of 6.28 years, 42 (15.9%) patients experienced arterial (n = 31) or venous thrombosis (n = 11). A higher leukocyte count correlated with an increased risk for total thrombosis and in particular, with an increased risk for arterial thrombosis (P = 0.005, HR 1.15 and P = 0.047, HR 1.12, respectively). A platelet count above 870 × 10⁹/L was associated with a lower risk for total thrombosis and also for venous thrombosis (P = 0.022, HR 0.44 and P = 0.027, HR 0.19). Moreover, a lower hemoglobin level was associated with an increased risk for venous thrombosis (P = 0.007, HR 0.59). Our data indicate that leukocytosis is a prominent risk factor for thrombosis in early/prefibrotic MF.

Foodborne pathogens in in-line milk filters and associated on-farm risk factors in dairy farms authorized to produce and sell raw milk in northern Italy

All dairy farms authorized to produce and sell raw milk in a province of Northern Italy were investigated to determine the presence of Campylobacter spp., verocytotoxin-producing Escherichia coli (VTEC), Listeria monocytogenes, and Salmonella spp. in in-line milk filters and to assess their association with suspected risk factors on farms. A logistic regression model was used to analyze data collected describing the characteristics and management practices of 27 farms and the microbiological status of 378 in-line milk filters by both culture-based and molecular methods. Thermotolerant Campylobacter, VTEC, and L. monocytogenes were detected in 24 (6.45%), 32 (8.4%), and 2 (0.5%) samples, respectively. No Salmonella spp. were detected. For risk analysis, data of L. monocytogenes and Salmonella spp. were not included in the model because of the low prevalence or absence of these organisms. The univariate analysis disclosed that the presence of VTEC and/or Campylobacter spp. in milk filters was associated with lack of cleanliness of bedding, water trough, and feed trough; nonevaluation of water hardness; lack of cleanliness of milk tank; and nonapplication of forestripping. After multivariate analysis, an association was observed with inadequate cleanliness of bedding and milk tank and the nonapplication of forestripping. PCR analysis of milk filters was a rapid and sensitive method for the microbiological evaluation of herd contamination status and should be included among the registration requirements for the authorization to produce and sell raw milk. Specific control actions must be incorporated into the farmer's daily practices to ensure the low-risk production of raw milk.

Primary antithrombotic prevention in carriers of antiphospholipid antibodies without systemic autoimmune disorders

Primary antithrombotic prevention with aspirin is not indicated in asymptomatic patients with confirmed antiphospholipid (aPL) positivity without systemic autoimmune disorders because: a) the estimated prevalence of thrombosis in unselected cases is about 1% patient-years (range 0–2.8); b) this level of thrombotic risk is equivalent to that of major bleeding associated with the use of aspirin and therefore the expected benefit does not outweigh the risk; c) these expectations have been confirmed by at least one randomized clinical trial, although with methodological limits. The management of modifiable thrombotic risk factors can be an alternative and safer strategy, considering that many vascular events occur in the presence of concomitant non-aPL triggering conditions. Whether primary prophylaxis with aspirin may be useful for some subsets of aPL patients at particularly high thrombotic risk, such as those with overt systemic autoimmune disorders or with special patterns of antibodies (‘triple positivity’), remains to be established.

Unraveling the genetic underpinnings of myeloproliferative neoplasms and understanding their effect on disease course and response to therapy: proceedings from the 6th International Post-ASH Symposium

Immediately after the annual scientific meeting of the American Society of Hematology (ASH), a select group of clinical and laboratory investigators in myeloproliferative neoplasms (MPN) is summoned to a post-ASH conference on chronic myeloid leukemia and the BCR-ABL1-negative MPN. The 6th such meeting occurred on December 13–14,2011, in La Jolla, California, USA, under the direction of its founder,Dr. Tariq Mughal. The current document is the first of two reports on this post-ASH event and summarizes the most recent preclinical and clinical advances in polycythemia vera, essential thrombocythemia,and primary myelofibrosis.

Hydroxyurea-related toxicity in 3,411 patients with Ph'-negative MPN

Hydroxyurea (Hydroxycarbamide; HU) is commonly used for the long-term treatment of patients with Philadelphia-chromosome negative chronic myeloproliferative neoplasms (MPNs). It is considered a first-choice agent for the treatment of these disorders as underlined by the European Leukemia Net Consensus Conference [1], although it is formally approved for this indication in some countries only. The drug is reportedly well tolerated in the large majority of subjects, although systemic and/or localized toxicities have been reported. Consensus criteria for definition of "intolerance" to HU have been described;patients who develop intolerance are candidate for second-line therapy and, more recently, for investigational drugs. However, no epidemiologic information about the occurrence of the most clinically significant HU-associated adverse events is yet available. In this study, the authors report on a multicenter series of 3,411 patients who were treated with HU among which 184, accounting for 5% of total, developed significant drug-related toxicities. These data provide an estimate of the frequency and a detailed characterization of clinically significant HU-related toxicities; these information have relevance for the management of MPN patients who require second-line therapy after developing HU-related intolerance.

Initial bone marrow reticulin fibrosis in polycythemia vera exerts an impact on clinical outcome

We examined the prevalence and prognostic relevance of bone marrow reticulin fibrosis in 526 patients with World Health Organization-defined polycythemia vera evaluated at the time of initial diagnosis. Seventy-four patients (14%) displayed mostly grade 1 reticulin fibrosis, with only 2 cases showing higher-grade fibrosis. Presenting clinical and laboratory characteristics, including JAK2V617F allele burden, between patients with and without fibrosis were similar for the most part, with the exception of a higher prevalence of palpable splenomegaly in patients with fibrosis (P < .01). Patients with fibrosis were less prone to experience thrombosis during their clinical course (1.1 vs 2.7 per 100 patient-years; P = .03) and more prone to develop post-polycythemia vera myelofibrosis (2.2 vs 0.8 per 100 patient-years; P = .01). There was no significant difference between the 2 groups in terms of overall or leukemia-free survival. The present study clarifies the incidence, degree, and prognostic relevance of bone marrow fibrosis obtained at time of initial diagnosis of polycythemia vera.

Sale of raw milk in northern Italy: food safety implications and comparison of different analytical methodologies for detection of foodborne pathogens

The safety of raw milk sold in Northern Italy was investigated in relation to hygiene quality parameters and presence of Salmonella spp., Listeria monocytogenes, thermotolerant Campylobacter, and Verocytotoxin producing Escherichia coli O157:H7. The performance of different analytical methods used-official culture method (ISO), modified Bacteriological Analytical Manual cultural method (mBAM), and polymerase chain reaction (PCR)-was evaluated. The presence of Mycobacterium avium subsp. paratuberculosis (Map) was investigated only by PCR. All samples met regulations for alkaline phosphatase and inhibitory substance, while 18% and 44.8% of samples collected from vending machines had, respectively, somatic cell count (SCC) >300,000/mL and total bacterial count (TBC) >50,000 CFU/mL. The correlation between hygienic quality parameters in samples collected from bulk tank and vending machines showed a significant increase of TBC in vending machines meaning that raw milk was mishandled during distribution and sale. All pathogens investigated were detected in raw milk sold at vending machines; a total of five samples (5%) had at least one pathogen, of which two were detected by PCR and three by mBAM. None of the samples was positive by cultural ISO methods. Even if the comparison of analytical methods showed that none performs significantly better than the others, testing a higher volume of milk (25 versus 210 mL) affects significantly the detection rate of pathogens. Three samples (3%) were positive for Map, suggesting that raw milk is a significant source of Map exposure for consumers. The observed TBC increase and the detection of several pathogenic bacteria pose questions on the safety of raw milk; the use of ISO seems inefficient in detecting a low contamination level of pathogens in milk and consequently not appropriate as official method for testing. In order to ensure consumer's safety, a new approach for the raw milk chain is required.

Blood tests may predict early primary myelofibrosis in patients presenting with essential thrombocythemia

According to World Health Organization (WHO)-defined criteria, patients presenting clinically as essential thrombocythemia (ET) may show early primary myelofibrosis (PMF) with accompanying thrombocythemia [1]. Previous clinicopathological studies revealed that laboratory parameters like gender-matched hemoglobin (Hb), white blood cell (WBC) count, and particularly lactate dehydrogenase (LDH) values are significantly different in PMF [2]. By strictly applying the WHO criteria, our investigation was aimed to study sensitivity and specificity of these features in an exploratory cohort of 536 patients and to validate the results on an independently recruited series of 321 strictly corresponding patients. The discriminatory power of these parameters (Hb, WBC, and LDH) was tested by plotting their receiver operating characteristic curves. The best performance was found for LDH (areas under the curve, AUC 5 0.7059). WBC and Hb had superimposable curves, with AUC of 0.6279 and 0.6257, respectively. A diagnostic algorithm was generated by applying these parameters in a stepwise fashion. Nearly half of the patients could be correctly allocated to WHO-defined ET or early PMF in both cohorts investigated. It is important to note that this result does not substitute bone marrow morphology with hematological parameters, however, in clinical practice may alert physicians to get more suspicious of early PMF in a patient presumably presenting with ET.

Questions and answers on the use of dabigatran and perspectives on the use of other new oral anticoagulants in patients with atrial fibrillation. A consensus document of the Italian Federation of Thrombosis Centers (FCSA)

Dabigatran and other new oral anticoagulants (OAC) represent a step forward in stroke prevention in patients with atrial fibrillation (AF). They indeed have been shown to be an alternative to vitamin K antagonists (VKAs) without the burden of laboratory control. However, these new drugs compete with an effective and well-established therapy, thus bringing about a series of questions and doubts. In this report members of the board of the Italian Federation of Thrombosis Centers (FCSA) answer some questions every clinician might be confronted with.

Incidence and risk factors for bleeding in 1104 patients with essential thrombocythemia or prefibrotic myelofibrosis diagnosed according to the 2008 WHO criteria

In an international study of 1104 patients with essential thrombocythemia (ET), a histological review according to the 2008 World Health Organization (WHO) criteria confirmed ET in 891 patients (WHO-ET, 81%), and revised the diagnosis to prefibrotic primary myelofibrosis (PMF) in 180 patients (PMF, 16%). Major bleeding during follow-up occurred in 55 (6%) WHO-ET and 21 (12%) PMF patients (P = 0.009), at a rate of 0.79 and 1.39% patients per year, respectively, (P = 0.039). In a multivariable analysis, predictors of bleeding included diagnosis of PMF (P = 0.05; hazard ratio (HR) 1.74), leukocytosis (P = 0.04; HR 1.74), previous hemorrhage (P = 0.025; HR 2.35) and aspirin therapy (P=0.001; HR 3.16). The analysis restricted to patients with WHO-ET confirmed previous hemorrhage (P = 0.043; HR 1.92) and aspirin (P=0.027; HR 2.24) as independent risk factors. The current study reveals that major bleeding associated with thrombocytosis might be relatively specific to PMF, as opposed to WHO-defined ET. Furthermore, it shows that low-dose aspirin exacerbates these hemorrhagic events of PMF. In contrast, thrombocytosis per se was not a risk factor for bleeding; however, low-dose aspirin had a synergistic hemorrhagic effect unmasking the bleeding tendency of patients with extreme thrombocytosis. These observations carry significant therapeutic implications in these two WHO entities.

Two unlinked cases of foodborne botulism in Italy at the beginning of 2010

The study provides data on two cases of foodborne botulism caused by consumption of commercial vegetable products: artichoke preserve and cream of vegetable soup. By mouse bioassay, Clostridium botulinum toxin in both the suspected food samples was detected and identified as type B toxin. The detection of C. botulinum toxin in the artichoke preserve indicates an inadequate food production technology while the presence of C. botulinum toxin in the vegetable soup appeared to be related to wrong behavior on the part of the consumer and to faulty food preservation. The study confirms that an early identification and reporting of suspected botulism cases is vital in the prevention of accidental widespread outbreaks.

Platelet-induced thrombin generation by the calibrated automated thrombogram assay is increased in patients with essential thrombocythemia and polycythemia vera

The platelet contribution to the thrombophilic state of patients with myeloproliferative neoplasms (MPNs), i.e., essential thrombocythemia (ET) and polycythemia vera (PV), remains uncertain. In this study we aimed to characterize the thrombin generation (TG) potential expressed by platelets from these subjects, compare it to normal platelets, and identify what factors might be responsible for platelet TG. In a group of 140 MPN patients (80 ET and 60 PV) and 72 healthy subjects, we measured the global procoagulant potential of platelet-rich plasma (PRP) utilizing the TG assay by the calibrated automated thrombogram (CAT). To characterize the procoagulant contribution of platelets in PRP, the TG of both isolated platelets and platelet-poor plasma was measured, and the platelet surface expression of TF was determined. Finally, the activation status of platelets was assessed by the levels of P-selectin expressed on platelet surface. MPN patients had significantly increased PRP and isolated platelet TG potential compared to controls. This was associated to the occurrence of platelet activation. Patients carriers of the JAK2V617F mutation showed the highest values of TG and platelet surface TF and P-selectin. Platelet TG potential was significantly lower in hydroxyurea(HU) compared to non-HU-treated patients and was lowest in HU-treated JAK2V617F carriers. In subjects not receiving HU, platelet TG significantly increased by JAK2V617F allele burden increment (P < 0.05).This study demonstrates a platelet-dependent form of hypercoagulability in MPN patients, particularly in those carriers of the JAK2V617F mutation. The cytoreductive therapy with HU significantly affects this prothrombotic phenotype.

Mutations with epigenetic effects in myeloproliferative neoplasms and recent progress in treatment: Proceedings from the 5th International Post-ASH Symposium

Immediately following the 2010 annual American Society of Hematology (ASH) meeting, the 5th International Post-ASH Symposium on Chronic Myelogenous Leukemia and BCR-ABL1-Negative Myeloproliferative Neoplasms (MPNs) took place on 7–8 December 2010 in Orlando, Florida, USA. During this meeting, the most recent advances in laboratory research and clinical practice, including those that were presented at the 2010 ASH meeting, were discussed among recognized authorities in the field. The current paper summarizes the proceedings of this meeting in BCR-ABL1-negative MPN. We provide a detailed overview of new mutations with putative epigenetic effects (TET oncogene family member 2 (TET2), additional sex comb-like 1 (ASXL1), isocitrate dehydrogenase (IDH) and enhancer of zeste homolog 2 (EZH2)) and an update on treatment with Janus kinase (JAK) inhibitors, pomalidomide, everolimus, interferon-α, midostaurin and cladribine. In addition, the new ‘Dynamic International Prognostic Scoring System (DIPSS)-plus' prognostic model for primary myelofibrosis (PMF) and the clinical relevance of distinguishing essential thrombocythemia from prefibrotic PMF are discussed.

Philadelphia-negative classical myeloproliferative neoplasms: critical concepts and management recommendations from European LeukemiaNet

We present a review of critical concepts and produce recommendations on the management of Philadelphia-negative classical myeloproliferative neoplasms, including monitoring, response definition, first- and second-line therapy, and therapy for special issues. Key questions were selected according the criterion of clinical relevance. Statements were produced using a Delphi process, and two consensus conferences involving a panel of 21 experts appointed by the European LeukemiaNet (ELN) were convened. Patients with polycythemia vera (PV) and essential thrombocythemia (ET) should be defined as high risk if age is greater than 60 years or there is a history of previous thrombosis. Risk stratification in primary myelofibrosis (PMF) should start with the International Prognostic Scoring System (IPSS) for newly diagnosed patients and dynamic IPSS for patients being seen during their disease course, with the addition of cytogenetics evaluation and transfusion status. High-risk patients with PV should be managed with phlebotomy, low-dose aspirin, and cytoreduction, with either hydroxyurea or interferon at any age. High-risk patients with ET should be managed with cytoreduction, using hydroxyurea at any age. Monitoring response in PV and ET should use the ELN clinicohematologic criteria. Corticosteroids, androgens, erythropoiesis-stimulating agents, and immunomodulators are recommended to treat anemia of PMF, whereas hydroxyurea is the first-line treatment of PMF-associated splenomegaly. Indications for splenectomy include symptomatic portal hypertension, drug-refractory painful splenomegaly, and frequent RBC transfusions. The risk of allogeneic stem-cell transplantation-related complications is justified in transplantation-eligible patients whose median survival time is expected to be less than 5 years.

Inflammation and thrombosis in essential thrombocythemia and polycythemia vera: different role of C-reactive protein and pentraxin 3

We tested the hypothesis that levels of pentraxin high sensitivity C-reactive protein and pentraxin 3 might be correlated with cardiovascular complications in patients with essential thrombocythemia and polycythemia vera. High sensitivity C-reactive protein and pentraxin 3 were measured in 244 consecutive essential thrombocythemia and polycythemia vera patients in whom, after a median follow up of 5.3 years (range 0-24), 68 cardiovascular events were diagnosed. The highest C-reactive protein tertile was compared with the lowest (>3 vs. <1 mg/L) and correlated with age (P=0.001), phenotype (polycythemia vera vs. essential thrombocythemia, P=0.006), cardiovascular risk factors (P=0.012) and JAK2V617F allele burden greater than 50% (P=0.003). Major thrombosis rate was higher in the highest C-reactive protein tertile (P=0.01) and lower at the highest pentraxin 3 levels (P=0.045). These associations remained significant in multivariate analyses and indicate that blood levels of high sensitivity C-reactive protein and petraxin 3 independently and in opposite ways modulate the intrinsic risk of cardiovascular events in patients with myeloproliferative disorders.

A pilot study of the Histone-Deacetylase inhibitor Givinostat in patients with JAK2V617F positive chronic myeloproliferative neoplasms

A phase II A study was conducted to evaluate the safety and efficacy of Givinostat, a novel Histone-Deacetylases inhibitor, in patients with Polycythaemia Vera (PV, n = 12), Essential Thrombocythaemia (ET, n = 1) and Myelofibrosis (n = 16), bearing the JAK2V617F mutation. The study was approved by the local ethics committees and all human participants gave written informed consent. Givinostat was given orally for 24 weeks at a starting dose of 50 mg twice daily. The median treatment duration was 20 weeks. Reasons for treatment discontinuation were disease progression (n = 6), grade 2 thrombocytopenia (n = 1), psychiatric symptoms (n = 1) and withdrawn consent (n = 2). A dose reduction was applied in 10 patients while a temporary interruption occurred in 15. Among 13 PV/ET patients, 1 complete, 6 partial and 4 no responses were documented at study end while 2 patients went off-study, prematurely. Three major responses were registered among 16 MF patients. Pruritus disappeared in most patients and reduction of splenomegaly was observed in 75% of PV/ET and 38% of MF patients. Reverse transcription polymerase chain reaction identified a trend to reduction of the JAK2V617F allele burden. Givinostat was well tolerated and could induce haematological response in most PV and some MF patients.