bl-4162a and Thrombosis

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.

Topics: Hemorrhage; Humans; Hydroxyurea; Quinazolines; Thrombocythemia, Essential; Thrombosis

The clinical course of the classic myeloproliferative neoplasms (MPNs) is burdened by an increased rate of cardiovascular events, which are the major cause of mortality. Age and history of thrombosis are the criteria used to stratify patients to the most appropriate therapeutic options. However, the mechanisms ultimately responsible for the increased thrombotic tendency have not yet been elucidated; abnormalities of blood cell count, neutrophil and platelet activation, and a state of hypercoagulability can all occur. Recurrent mutations in JAK2 or MPL have been described in MPNs and serve as disease markers. There is also evidence that a JAK2V617F mutant state represents an independent factor associated with thrombosis, and abnormalities of cell function attributable to JAK2V617F have been characterized. It is hoped that elucidation of the role mutant JAK2 plays in MPNs will improve our understanding of the pathophysiology of thrombosis and eventually result in improved patient treatment using molecularly targeted drugs.

Topics: Amino Acid Substitution; Aspirin; Cardiovascular Diseases; Clinical Trials as Topic; Fibrinolytic Agents; Humans; Incidence; Interferon-alpha; Janus Kinase 2; Multicenter Studies as Topic; Mutation, Missense; Myeloproliferative Disorders; Phenotype; Point Mutation; Quinazolines; Thrombophilia; Thrombosis

Polycythemia vera (PV) and essential thrombocythemia (ET) may rarely evolve into acute leukemia as part of their natural history. Cytogenetic abnormalities and the use of alkylating agents can enhance the risk of this transformation. Hydroxyurea (HU) has a limited, if any, leukemogenic potential and should be considered the current cytotoxic drug for patients at high risk for thrombotic complications, ie, those with age above 60 years or previous thrombotic events. Interferon-alpha (IFN-alpha) and anagrelide are known not to be leukemogenic and might have a role in younger patients. However, no controlled clinical trials of efficacy and safety are available for these two drugs and the occurrence of side effects may be a limiting factor for their widespread use.

Topics: Age Factors; Aged; Antineoplastic Agents, Alkylating; Antiviral Agents; Disease Progression; Female; Humans; Hydroxyurea; Interferon-alpha; Leukemia; Male; Middle Aged; Platelet Aggregation Inhibitors; Polycythemia Vera; Quinazolines; Risk Factors; Thrombocythemia, Essential; Thrombosis

Essential thrombocythemia (ET), one of the chronic myeloproliferative disorders, exposes individuals to significantly increased risk for thrombohemorrhagic complications. Epidemiologic data indicate that the two most prominent risk factors for thrombosis are age greater than 60 years or a history of or presentation with thrombosis at any age. Age is an important factor in selecting among therapeutic options, as the agents used to treat ET may contribute to acute leukemic transformation and other secondary malignancies. Whether or not hydroxyurea (HU) carries these risks is controversial and unresolved, but the uncertainty is a basis for avoiding it in young patients. Alternatives to HU that have established efficacy in lowering platelet counts in ET are interferon and anagrelide. Both are highly effective in reducing platelet numbers, and are apparently not associated with leukemogenicity or mutagenicity. However, approximately 30% of patients find interferon intolerable for long-term therapy. Anagrelide offers the advantage of oral dosing and long-term effectiveness at managing platelet counts. A recent long-term study of young ET patients treated with anagrelide found that all thrombohemorrhagic events occurred in patients with platelet counts greater than 0.4 x 10(9)/L, adding to the evidence that reduction of platelet counts to normal may be required for optimal control of risk.

Topics: Age Factors; Drug Therapy, Combination; Humans; Hydroxyurea; Interferon-alpha; Platelet Aggregation Inhibitors; Platelet Count; Quinazolines; Risk Factors; Thrombocythemia, Essential; Thrombosis

The clinical course in both polycythaemia vera (PV) and essential thrombocythaemia (ET) is characterized by significant thrombohaemorrhagic complications and variable risk of disease transformation into myeloid metaplasia with myelofibrosis or acute myeloid leukaemia. Randomized studies have shown that the risk of thrombosis was significantly reduced in ET with the use of hydroxyurea (HU) and in PV with the use of chlorambucil or 32P. However, the use of chlorambucil or 32P has been associated with an increased risk of leukaemic transformation. Subsequently, other studies have suggested that both HU and pipobroman may be less leukaemogenic and as effective as chlorambucil and 32P for preventing thrombosis in PV. However, the results from these prospective studies have raised concern that even HU and pipobroman may be associated with excess leukaemic events in both ET and PV. The recent introduction of anagrelide as a specific platelet-lowering agent, the demonstration of treatment efficacy with interferon-alpha, and the revived interest in using low-dose acetylsalicylic acid provide the opportunity to initiate prospective randomized studies incorporating these treatments.

Topics: Adult; Aged; Aspirin; Chlorambucil; Disease Progression; Female; Hemorrhage; Humans; Hydroxyurea; Interferon-alpha; Leukemia, Myeloid; Leukemia, Radiation-Induced; Male; Middle Aged; Phlebotomy; Phosphorus Radioisotopes; Pipobroman; Polycythemia Vera; Primary Myelofibrosis; Prospective Studies; Quinazolines; Thrombocythemia, Essential; Thrombosis

Anagrelide is an oral imidazoquinazoline agent with an anti-cyclic AMP phosphodiesterase activity and inhibits platelet aggregation in both humans and animals. In addition, it has in humans a species-specific platelet-lowering activity observed at dose levels lower than those required to inhibit platelet aggregation. Because of this, the drug has been tested in patients with clonal thrombocytosis and has been shown to have potent platelet-reducing activity in essential thrombocythemia (ET) and related disorders. The mechanism of action may involve the drug's interference with megakaryocyte maturation. More than 90% of patients with ET respond to anagrelide regardless of the presence or absence of previous therapy. The responses are durable with a median maintenance dose of approximately 2 to 2.5 mg/day. Side effects are related mostly to the drug's direct vasodilating and positive inotropic effects and include headache, fluid retention, tachycardia, and arryhthmias. The place of anagrelide therapy in the current management of patients with ET is discussed.

Topics: Animals; Bone Marrow; Cardiovascular Diseases; Clinical Trials as Topic; Cohort Studies; Hematopoiesis; Hemodynamics; Humans; Megakaryocytes; Middle Aged; Myeloproliferative Disorders; Platelet Aggregation Inhibitors; Quinazolines; Thrombocythemia, Essential; Thrombosis

The therapeutic strategy in patients with Essential Thrombocythemia (ET) is a difficult balance between the prevention of bleeding and thrombotic complications and the risks of drug side effects and toxicity. Major bleeding is rare and seem to be related to higher platelet counts: therefore, a platelet count over 1500 x 10(9)/L is generally regarded as an indication for cytoreduction. Thrombotic complications include microvascular occlusive symptoms, which are reversible with low-dose aspirin, and large vessels thrombosis. The risk of major thrombosis is higher in ET patients aged more than 60 ys. and with previous occlusive event. In this high-risk group, the non-alkylating agent hydroxyurea (HU) significantly reduces the rate of vascular complications and has emerged as the treatment of choice. However, the long-term risk/benefit of HU remains disputed because its leukemogenic potential has not been ruled out. This holds also for other myelosuppressive agents, such as busulphan and pipobroman. Other drugs of particular interest for young patients include recombinant alpha-interferon (IFN) and Anagrelide. Both of them are effective in lowering platelet count, but their efficacy in reducing clinical complications remains to be demonstrated. However, both IFN and Anagrelide have shown to have frequent and clinically important side effects. Thus, further clinical studies are required to establish their role in the strategy of ET patient treatment.

Topics: Adult; Aged; Alkylating Agents; Anemia, Megaloblastic; Arrhythmias, Cardiac; Bone Marrow Diseases; Busulfan; Female; Hemorrhage; Humans; Hydroxyurea; Immunologic Factors; Incidence; Interferon-alpha; Ischemic Attack, Transient; Leukemia; Male; Middle Aged; Pipobroman; Platelet Aggregation Inhibitors; Platelet Count; Prognosis; Quinazolines; Risk Factors; Thrombocythemia, Essential; Thrombosis

Platelets play a central role in atherothrombotic events. We investigated the effect of a novel platelet-lowering agent, rafigrelide, on thrombus formation and characteristics. In this phase 1, open-label, non-randomised, single-sequence, crossover study, healthy male volunteers received rafigrelide for 14 days (Period 1). Following a ≥6-week washout period, they then received rafigrelide + acetylsalicylic acid (ASA) for 14 days (Period 2). Thrombus formation was assessed ex vivo using the Badimon perfusion chamber, and thrombus characteristics were assessed using thromboelastography. A total of 15 volunteers were enrolled in the study and were assigned to Panel A or Panel B, which had different schedules of assessments. In Panel A, after treatment with rafigrelide alone (Period 1), mean (± standard deviation) platelet count was reduced from 283 (± 17) × 10⁹/l at Day 1, to 125 (± 47) × 10⁹/l at Day 14 (n=6) and thrombus area reduced under high and low shear conditions. Reductions in thrombus area under high shear conditions correlated with reductions in platelet count (r²=0.11, p=0.022; n=12). Rafigrelide treatment prolonged clot formation time and reduced clot strength. The addition of ASA to rafigrelide (Period 2) had no additional effect on platelet count or thrombus area under high or low shear conditions. Similar results were seen in Panel B for all parameters. The most common adverse events (≥3 participants per period) were thrombocytopenia and headache. While confirming the platelet-lowering effects of rafigrelide, this early phase study also indicates that rafigrelide has antithrombotic properties under both high and low shear conditions.

Topics: Adult; Aspirin; Blood Coagulation; Blood Platelets; Cross-Over Studies; Drug Therapy, Combination; Headache; Humans; Imidazoles; Male; Platelet Aggregation Inhibitors; Platelet Count; Quinazolines; Thrombelastography; Thrombocytopenia; Thrombosis

Essential thrombocythemia (ET) manifests substantial interpatient heterogeneity in rates of thrombosis, hemorrhage, and disease transformation. Bone marrow histology reflects underlying disease activity in ET but many morphological features show poor reproducibility.. We evaluated the clinical significance of bone marrow reticulin, a measure previously shown to have relatively high interobserver reliability, in a large, prospectively-studied cohort of ET patients.. Reticulin grade positively correlated with white blood cell (P = .05) and platelet counts (P = .0001) at diagnosis. Elevated reticulin levels at presentation predicted higher rates of arterial thrombosis (hazard ratio [HR], 1.8; 95% CI, 1.1 to 2.9; P = .01), major hemorrhage (HR, 2.0; 95% CI, 1.0 to 3.9; P = .05), and myelofibrotic transformation (HR, 5.5; 95% CI, 1.7 to 18.4; P = .0007) independently of known risk factors. Higher reticulin levels at diagnosis were associated with greater subsequent falls in hemoglobin levels in patients treated with anagrelide (P < .0001), but not in those receiving hydroxyurea (P = .9). Moreover, serial trephine specimens in patients randomly assigned to anagrelide showed significantly greater increases in reticulin grade compared with those allocated to hydroxyurea (P = .0003), and four patients who developed increased bone marrow reticulin on anagrelide showed regression of fibrosis when switched to hydroxyurea. These data suggest that patients receiving anagrelide therapy should undergo surveillance bone marrow biopsy every 2 to 3 years and that those who show substantially increasing reticulin levels are at risk of myelofibrotic transformation and may benefit from changing therapy before adverse clinical features develop.. Our results demonstrate that bone marrow reticulin grade at diagnosis represents an independent prognostic marker in ET, reflecting activity and/or duration of disease, with implications for the monitoring of patients receiving anagrelide.

Topics: Biomarkers; Bone Marrow; Hemoglobins; Hemorrhage; Humans; Hydroxyurea; Leukocyte Count; Platelet Aggregation Inhibitors; Platelet Count; Primary Myelofibrosis; Prognosis; Prospective Studies; Quinazolines; Reticulin; Thrombocythemia, Essential; Thrombosis

Topics: Adult; Aged; Antithrombin III; Aspirin; Drug Therapy, Combination; Female; Fibrin Fibrinogen Degradation Products; Hemorrhage; Humans; Hydroxyurea; Male; Middle Aged; Peptide Fragments; Peptide Hydrolases; Platelet Activation; Platelet Aggregation Inhibitors; Platelet Count; Platelet Factor 4; Prothrombin; Quinazolines; Thrombocythemia, Essential; Thrombosis

We conducted a randomized comparison of hydroxyurea with anagrelide in the treatment of essential thrombocythemia.. A total of 809 patients with essential thrombocythemia who were at high risk for vascular events received low-dose aspirin plus either anagrelide or hydroxyurea. The composite primary end point was the actuarial risk of arterial thrombosis (myocardial infarction, unstable angina, cerebrovascular accident, transient ischemic attack, or peripheral arterial thrombosis), venous thrombosis (deep-vein thrombosis, splanchnic-vein thrombosis, or pulmonary embolism), serious hemorrhage, or death from thrombotic or hemorrhagic causes.. After a median follow-up of 39 months, patients in the anagrelide group were significantly more likely than those in the hydroxyurea group to have reached the primary end point (odds ratio, 1.57; 95 percent confidence interval, 1.04 to 2.37; P=0.03). As compared with hydroxyurea plus aspirin, anagrelide plus aspirin was associated with increased rates of arterial thrombosis (P=0.004), serious hemorrhage (P=0.008), and transformation to myelofibrosis (P=0.01) but with a decreased rate of venous thromboembolism (P=0.006). Patients receiving anagrelide were more likely to withdraw from their assigned treatment (P<0.001). Equivalent long-term control of the platelet count was achieved in both groups.. Hydroxyurea plus low-dose aspirin is superior to anagrelide plus low-dose aspirin for patients with essential thrombocythemia at high risk for vascular events.

Topics: Adult; Aged; Aged, 80 and over; Antineoplastic Agents; Aspirin; Drug Therapy, Combination; Female; Follow-Up Studies; Hemorrhage; Humans; Hydroxyurea; Leukemia, Myeloid, Acute; Male; Middle Aged; Platelet Aggregation Inhibitors; Platelet Count; Primary Myelofibrosis; Quinazolines; Thrombocythemia, Essential; Thrombosis

Anagrelide (ANA) is a platelet-specific cytoreductive agent utilized in the guideline-directed management of high-risk essential thrombocythemia. In the context of polycythemia vera (PV), ANA is occasionally employed in clinical practice, although data has not consistently demonstrated a benefit to targeting a platelet goal as a therapeutic endpoint. The aim of the current study was to delineate the patterns of ANA use in PV, and to describe outcomes and toxicities. Within a multi-center cohort of 527 patients with PV, 48 received ANA (9 excluded for absent data). 27 (69.2%) had high-risk PV, 10 (25.6%) had prior thrombosis, and none had extreme thrombocytosis, acquired von Willebrand disease, and/or documented resistance to hydroxyurea. While ANA effectively lowered median platelet count, 43.5% of patients had an unresolved thrombocytosis at time of ANA discontinuation. Treatment-emergent adverse events-including headaches, cardiac palpitations and arrhythmias, nausea, vomiting and/or diarrhea-led to ANA discontinuation in 76.9% of patients. Further, three patients experienced arterial thromboses during a median duration of 27.5 months of ANA therapy. In conclusion, this study highlights ANA's restrictive tolerability profile which, compounded by the absence of clear advantage to strict platelet control in PV, suggests the use of ANA should be limited in this setting.

Topics: Cytoreduction Surgical Procedures; Humans; Polycythemia Vera; Quinazolines; Thrombocythemia, Essential; Thrombocytosis; Thrombosis

Topics: Hemorrhage; Humans; Platelet Aggregation Inhibitors; Quinazolines; Thrombocythemia, Essential; Thrombosis

Anagrelide is a drug effective in reducing platelet counts in essential thrombocythemia (ET) and Ph1-negative myeloproliferative neoplasms. The aim of this study was to evaluate the real-life use of anagrelide in patients with ET followed over 25 years at the Haematological Institutes belonging to "Ph1-negative Myeloproliferative Neoplasms Latium Group.". Eligibility criteria were diagnosis of ET and treatment with anagrelide. Data were collected through an ad hoc case report form.. One hundred and fifty patients received anagrelide for a median time of 7.4 years (0.1-23.2). Anagrelide was administered as first-line therapy in 34.7% of patients, as second-line in 52% and as third-line in 13.3%: 85.4% responded to therapy. Sixty-eight/136 evaluable patients reported side effects: palpitations, peripheral vasodilation, anaemia, diarrhoea and gastric distress. Fourteen thrombotic (arterial 10, venous 4) and 51 bleeding events (minor 48, major 3) occurred. Sixteen/150 (10.6%) patients developed secondary myelofibrosis and 3/150 (2%) an acute myeloid leukaemia.. In our experience, anagrelide is an effective drug in reducing platelet levels in a high percentage of patients with ET. It is especially addressed to younger people. A careful assessment of the thrombotic risk and monitoring of cardiac function, at diagnosis and during follow-up, is mandatory.

Topics: Adult; Age Factors; Aged; Aged, 80 and over; Anemia; Disease Management; Disease Susceptibility; Drug Substitution; Female; Follow-Up Studies; Health Care Surveys; Humans; Italy; Male; Middle Aged; Pregnancy; Pregnancy Complications, Hematologic; Prognosis; Quinazolines; Retreatment; Retrospective Studies; Thrombocythemia, Essential; Thrombosis; Treatment Outcome; Young Adult

We report an extension study of patients with essential thrombocythaemia (ET) in the Hungarian Myeloproliferative Neoplasm (HUMYPRON) Registry, which demonstrated that over 6 years anagrelide significantly decreased the number of patients experiencing minor arterial and minor venous thrombotic events (TEs) vs hydroxyurea+aspirin.. Data on patients with ET were collected through completion of a questionnaire developed according to 2008 WHO diagnostic criteria and with regard to Landolfi, Tefferi and IPSET criteria for thrombotic risk. Data were entered into the registry from 14 haematological centres. TEs, secondary malignancies, disease progression and survival were compared between patients with ET treated with anagrelide (n = 116) and with hydroxyurea+aspirin (n = 121).. Patients were followed for (median) 10 years. A between-group difference in the number of patients with TEs was observed (25.9% anagrelide vs 38.0% hydroxyurea+aspirin; P = .052). Minor arterial events were more frequently reported in the hydroxyurea+aspirin group (P < .001); there were marginally more reports of major arterial events in the anagrelide group (P = .049). TE prior to diagnosis was found to significantly influence TE incidence (P > .001). Progression-free survival (P = .004) and survival (P = .001) were significantly increased for the anagrelide group vs hydroxyurea+aspirin.. Anagrelide reduced TEs, and increased progression-free and overall survival vs hydroxyurea+aspirin over (median) 10 years.

Topics: Aspirin; Drug Therapy, Combination; Health Care Surveys; Humans; Hungary; Hydroxyurea; Quinazolines; Registries; Thrombocythemia, Essential; Thrombosis; Treatment Outcome

First-line cytoreductive drug of choice in high risk essential thrombocythemia (ET) is currently hydroxyurea, a practice based on the results of a randomized study; second-line drugs of choice include pegylated interferon-α, busulfan and anagrelide. Anagrelide clinical trials were pioneered by the late Murray N. Silverstein (1928-1998) of the Mayo Clinic whose studies led to FDA approval in March 1997. The current study represents a retrospective examination of the potential impact of anagrelide therapy on survival and disease complications in ET. 1076 patients with ET were considered (median age 58 years; females 63%); risk distribution, according to the international prognostic score for ET (IPSET), was 28% high, 42% intermediate, and 30% low. Overall (OS), myelofibrosis-free (MFFS) and thrombosis-free survival data were compared for ET patients diagnosed before and after the 1997 FDA approval date for anagrelide; a significant difference was apparent in OS (P = .006; HR 1.4, 95% CI 1.1-1.7) and MFFS (P < .001; HR 4.2, 95% CI 2.7-6.5), in favor of patients diagnosed prior to 1997; the difference was sustained during multivariable analysis that included IPSET. Similarly stratified survival data in polycythemia vera (n = 665) and primary myelofibrosis (n = 1282) showed no similar impact on survival (P = .3 and .17, respectively). The current study represents a retrospective analysis and suggests significantly decreased OS and MFFS in ET patients diagnosed after the FDA approval date of anagrelide. Whether or not anagrelide therapy was to blame for the worsening of OS and MFFS over time cannot be assumed and requires validation in a prospective study.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Bone Marrow; Disease Progression; Disease-Free Survival; Drug Approval; Female; Fibrosis; Humans; Kaplan-Meier Estimate; Male; Middle Aged; Mortality; Platelet Aggregation Inhibitors; Polycythemia Vera; Primary Myelofibrosis; Prognosis; Proportional Hazards Models; Quinazolines; Retrospective Studies; Severity of Illness Index; Thrombocythemia, Essential; Thrombosis; Treatment Outcome; Young Adult

An 82-year-old woman who had a history of essential thrombocythemia presented with ocular pain, bleeding, and decreased visual acuity of the left eye. Orbital computed tomography revealed a relatively well-defined homogenous mass-like lesion in the left subconjunctival and intraconal space. Conjunctival biopsy showed acute inflammation with necrosis, vascular ectasia with thrombosis and hemorrhage. After the treatment with hydroxyurea and anagrelide, her symptom and lesion were markedly improved. Hematologic disorders like essential thrombocythemia should be considered in patients with severe spontaneous bleeding around the eye.

Topics: Aged, 80 and over; Biopsy; Conjunctiva; Eye Hemorrhage; Female; Hematologic Agents; Humans; Hydroxyurea; Orbit; Quinazolines; Thrombocythemia, Essential; Thrombosis; Tomography, X-Ray Computed; Treatment Outcome; Visual Acuity

To evaluate the reduction in thrombotic events (TE) in patients with essential thrombocythaemia (ET) treated with anagrelide versus hydroxyurea + aspirin (HU + ASA).. A questionnaire was developed using 2008 WHO diagnostic criteria, and thrombotic risk factors were stratified according to Landolfi criteria. Through questionnaire completion, clinicians at Hungarian haematological centres entered data into the Hungarian MPN Registry on patients with myeloproliferative neoplasms. Based on ET registry data, TEs in anagrelide-treated patients (n = 139) were compared with HU + ASA-treated patients (n = 141).. Patients were followed up for (median) 6 yr. TEs were reported in significantly fewer anagrelide-treated patients versus HU + ASA (15.1% versus 49.6%; P < 0.001). Numbers of major arterial and major venous events were similar between the groups, although there were over fivefold more minor arterial and minor venous events in the HU + ASA group (P < 0.001). While median age at diagnosis was older and length of follow-up shorter in the HU + ASA group (P < 0.05), this did not influence TE incidence; medication and TE before diagnosis only influenced TE incidence.. Anagrelide significantly decreased the number of patients experiencing minor arterial and minor venous TEs versus HU + ASA over 6 yr. Risk of TE after diagnosis was significantly increased if the patient had TE before diagnosis.

Topics: Adult; Aged; Aged, 80 and over; Aspirin; Drug Therapy, Combination; Female; Follow-Up Studies; Humans; Hungary; Hydroxyurea; Male; Middle Aged; Platelet Aggregation Inhibitors; Quinazolines; Risk; Thrombocythemia, Essential; Thrombosis

Controversies still exist regarding definition of the thrombotic risks in Ph- (BCR/ABL1-) myeloproliferative disorders with thrombocythemia (MPD-T). Platelet counts at diagnosis are currently not taken as a risk factor of thrombosis. In our cohort of 1179 patients with MPD-T, prospectively registered for anagrelide treatment, we found that the median platelet count prior to the thrombotic event was significantly higher than at time points without any ensuing thrombosis (453 vs. 400 × 10(9)/L, P < 0.001), albeit higher platelet counts at diagnosis tended to be connected with fewer thrombotic events (in contrast to WBC counts at diagnosis). The JAK2(V617F) mutation predicted both arterial and venous events, while age >65 yr, hypertension, diabetes mellitus, smoking, elevated triglyceride and homocysteine levels predicted arterial events only. For venous events, the specific thrombophilic risk factors (factor V 'Leiden' and others), antiphospholipid antibodies, and elevated factor VIII levels played a major role. During anagrelide treatment (± aspirin), we documented a decrease in both venous (6.7-fold) and arterial events (1.8-fold), while bleeding (mostly minor events) increased twofold compared to history. Our results suggest that keeping platelet counts at low levels may be a meaningful therapeutic measure to prevent thrombosis, although their counts at diagnosis lack any prognostic value.

Topics: Aged; Aged, 80 and over; Amino Acid Substitution; Aspirin; Female; Fusion Proteins, bcr-abl; Humans; Janus Kinase 2; Male; Mutation, Missense; Philadelphia Chromosome; Platelet Count; Prospective Studies; Quinazolines; Registries; Risk Factors; Thrombocytosis; Thrombosis

Although guidelines recommend normalization of platelet counts as an appropriate endpoint for treatment in high-risk essential thrombocythemia (ET), retrospective studies could not prove a correlation of diagnostic platelet counts with an increased thrombotic rate. There is, however, an increasing evidence that leukocytosis is an important risk factor for arterial thrombosis in myeloproliferative neoplasms.. This study considers the Austrian cohort of a European registry regarding the platelet-lowering therapeutic anagrelide. Influence of platelet and white blood cell (WBC) counts on thrombotic risk was assessed.. Using the calculated cutoffs of 574.5 G/L for platelets and 8.48 G/L for WBC counts, respectively, the Cox regression analysis revealed a clear influence of elevated platelets (P = 0.008) and WBC counts (P = 0.011) on the occurrence of major thrombotic events. The time to a major thrombotic event was shortest (P < 0.001) and the frequency related to 100 patient-years was highest (P = <0.001) when both platelet and WBC counts ranged above the calculated cutoffs.. Our data add evidence to the impact of platelet and WBC counts on thrombosis in ET. We suspect a particular interaction between platelets and WBC which might be based on a biological interplay depending on particular cell counts.

Topics: Aged; Blood Platelets; Female; Follow-Up Studies; Humans; Kaplan-Meier Estimate; Leukocyte Count; Male; Middle Aged; Platelet Aggregation Inhibitors; Prognosis; Proportional Hazards Models; Quinazolines; Registries; Risk Assessment; Thrombocythemia, Essential; Thrombosis

Evidences suggest an association between leukocytosis and thrombotic or hemorrhagic complication in polycythemia vera (PV) and essential thrombocythemia (ET), but clinical implication is not well known.. To evaluate whether leukocyte burden during follow-up is related to thrombotic or hemorrhagic events in PV and ET.. We retrospectively analyzed patients with PV or ET treated at Seoul National University Bundang Hospital, Korea. Time-weighted averages of leukocytes during the follow-up period were defined as leukocyte burden and were calculated for each patient and compared between patient subgroups. In each patient with events, leukocyte burden for the 3-month period before the event was compared with that for the entire follow-up period.. In 102 patients with PV or ET, 35 events (16 thrombotic, 19 hemorrhagic) occurred in 29 patients (median follow-up, 54months). Leukocyte burden were significantly higher in patients with events than in event-free patients (12,015×10(3) /μL vs. 9,567×10(3)/μL, P=0.003). The difference was more prominent in ET patients than in PV patients, and in patients with hemorrhagic events than in those with thrombotic events. In patients with events, the leukocyte burden in the pre-event period was higher than in the entire follow-up period (16,767×10(3)/μL vs. 12,015×10(3)/μL, P=0.002). In all patients, leukocyte burden during entire follow-up period of 11,000×10(3)/μL or higher was an independent risk factor for vascular events.. In PV or ET patients, leukocyte burden during disease course is related to increased incidence of thrombotic or hemorrhagic events.

Topics: Adult; Aged; Aged, 80 and over; Area Under Curve; Blood Cell Count; Comorbidity; Databases, Factual; Female; Follow-Up Studies; Hemorrhage; Hemorrhagic Disorders; Humans; Hydroxyurea; Leukocyte Count; Male; Middle Aged; Phlebotomy; Platelet Aggregation Inhibitors; Polycythemia Vera; Prognosis; Quinazolines; Retrospective Studies; Risk Factors; Thrombocythemia, Essential; Thrombophilia; Thrombosis; Young Adult

BCR/ABL-negative myeloproliferative neoplasms (MPNs) are considered to be acquired thrombophilic conditions. Persistently enhanced platelet activation has been described in polycythaemia vera and essential thrombocythaemia (ET), and shown to contribute to a higher risk of arterial and venous thrombotic complications. Recent studies have shown that mean platelet volume (MPV) and immature platelet fraction (IPF) can serve as useful markers of platelet activation and increased risk of thrombosis. The aim of the present study was to investigate the relationship between these parameters and thrombotic events in BCR/ABL-negative MPN. MPV values in patients with BCR/ABL-negative MPN were significantly higher than MPV values of healthy individuals (P < 0.001). No significant difference in MPV or IPF was observed between groups of patients with and without thrombotic complications (P = 0.441; P = 0.110); the difference in IPF values was close to the significance level for patients with ET (P = 0.073). Higher values of IPF were more frequently detected in patients with JAK2 V617F positivity (P = 0.030). These patients had higher MPV more frequently than others, and this difference was close to the significance level (P = 0.056). Further studies should validate the use of platelet parameters to identify patients at high risk.

Topics: Adult; Aged; Blood Platelets; Case-Control Studies; Female; Fusion Proteins, bcr-abl; Humans; Janus Kinase 2; Male; Mean Platelet Volume; Middle Aged; Mutation; Myeloproliferative Disorders; Platelet Aggregation Inhibitors; Quinazolines; Risk Factors; Thrombosis

In the Czech Republic, anagrelide (Thromboreductin®) [29] is used according to the recommendations of the Czech Working Group on Myeloproliferative Disorders (CZEMP) for treatment of thrombocythemia associated with Ph negative myeloproliferative disorders (MPDs). The patient data are collected in the Registry of patients with essential thrombocythemia (ET) and thrombocythemia associated with other MPDs treated with Thromboreductin®. At the end of 2012, the Registry contained data on 1,161 patients. Out of these, 1,159 patients with the dia-gnosis of a Ph negative MPD were evaluated. In 844 patients, precise WHO based dia-gnosis was known at start of therapy: 442 (52.4%) had ET, 108 (12.8%) had polycythaemia vera (PV) and 243 had primary myelofibrosis (PMF). The median age was 51 years at the time of diagnosis. At the time of the evaluation of the population, the median was 59 years. Every year, the proportion of patients newly treated with anagrelide as a firstline treatment in accordance with the CZEMP guidelines has been increasing. A growing proportion of patients has been treated with an additional cytoreducing drug, such as hydroxyurea and interferon. The majority of the patients received also an antiaggregant (or anticoagulant). More than a half of patients harbors the JAK2 mutation. A prompt decrease of platelet counts (as the response to Thromboreductin® treatment) was documented in most of the patients. After one year, 86.9% of patients had a full or partial response. In poorer responders, combination cytoreductive treatment was administered rather then the escalation of the Thromboreductin® dosage. There were 461 thrombotic manifestations in 363 patients and 61 haemorrhagic events in 57 patients recorded in the patients history. In the course of treatment (followup; F U), thrombosis was diagnosed only 179-times in 136 patients. There were more haemorrhagic events during F U: 109 events in 83 patients. Upon comparison of the number of events during F U to their numbers in history, we found a twofold decrease in arterial thrombosis, an almost twofold decrease in microvascular thrombosis and even a 6.6- fold decrease in venous thromboembolism events. Bleeding episodes increased 1.8-fold during F U. However, the vast majority of these hemorrhagic events were clinically insignificant. In conclusion, the treatment strategy according to the CZEMP guidelines incorporating anagrelide is highly effective in reducing the platelet counts, strongly prevents

Topics: Adult; Aged; Czech Republic; Female; Fibrinolytic Agents; Humans; Incidence; Male; Middle Aged; Myeloproliferative Disorders; Quinazolines; Registries; Thrombocythemia, Essential; Thrombosis

Resistance or intolerance to either of the 2 favored therapeutic choices for MPN is a common clinical challenge. To overcome this, we report our successful long-term experience with the combination of low-dose HU and AG.. Retrospective review identified 12 patients with essential thrombocythemia or polycythemia vera using combination therapy.. The mean duration of treatment 4.25 years. Combination therapy achieved a 45% median platelet count reduction with relatively low daily dose requirements (711 mg HU, 1.38 mg AG). All but 1 patient achieved partial (25%) or complete response (67%) according to European LeukemiaNet criteria. No arterial or venous thrombosis, or bleeding events occurred.. This is the longest follow-up experience of an HU and AG combination regimen in MPN. The low-dose combination regimen effectively achieved clinical and laboratory response while simultaneously minimizing dose-related adverse reactions, and should be the preferred therapeutic alternative to third-line agents in MPN patients who are resistant or intolerant to monotherapy.

Topics: Adult; Aged; Aged, 80 and over; Antineoplastic Combined Chemotherapy Protocols; Female; Humans; Hydroxyurea; Male; Middle Aged; Myeloproliferative Disorders; Philadelphia Chromosome; Polycythemia Vera; Quinazolines; Retrospective Studies; Thrombocythemia, Essential; Thrombosis

Myeloproliferative diseases - in particular essential thrombocythaemia (ET) - may be associated with increases in platelet count which put patients at risk of life-threatening complications such as thromboses and severe bleedings.. This multicentre post-marketing observational survey was conducted to assess the efficacy and safety of anagrelide under daily practice conditions in at-risk patients with ET who received anagrelide for the first time.. 198 patients (median age of 64 years, range 19-88 years) were included, 61.1% of the patients were women. The mean observation time was 6.2 +/- 1.7 months. Treatment with anagrelide lowered the platelet counts by a median of 316 x 10(9)/l from a median of 797 x 10(9)/l at the beginning of the observation to 470 x 10(9)/l at the last observation (log rank test, p < 0.001). Disease-related complications were reduced during treatment compared to 6 months prior to treatment (transient ischaemic attacks from 1.5 to 0.5%; thromboses from 7.6 to 0%). The number of bleedings remained the same at 1.5%. Adverse events were documented in 46 patients (23.2%). All observed adverse events were similar to those previously reported in clinical studies.. Anagrelide was effective in lowering the platelet count and was also well tolerated when used in daily clinical practice.

Topics: Adult; Aged; Aged, 80 and over; Female; Humans; Ischemic Attack, Transient; Male; Middle Aged; Platelet Aggregation Inhibitors; Platelet Count; Product Surveillance, Postmarketing; Quinazolines; Thrombocythemia, Essential; Thrombosis; Young Adult

Topics: Antineoplastic Agents; Aspirin; Drug Therapy, Combination; Hemorrhage; Humans; Hydroxyurea; Leukemia, Myeloid, Acute; Platelet Aggregation Inhibitors; Primary Myelofibrosis; Quinazolines; Risk Factors; Thrombocythemia, Essential; Thrombosis

We prospectively evaluated the effect of anagrelide (ANA) on platelets, PF4, F1+2, PAP, PAI-1, and TFPI and erythromelalgia in patients with essential thrombocythemia (ET) receiving anti-aggregants both pre- and post-ANA. At first, we observed a successful reduction of platelets, which was associated with normalization of platelet coagulant and endothelial function and disappearance of erythromelalgia. Secondly, we found a correlation between PF4 and TFPI and between TFPI and thrombosis, suggesting that erythromelalgia may be caused by platelet-mediated endothelial activation. These data may indicate that ANA may be efficacy in the treatment of symptomatic patients with ET.

Topics: Adult; Aged; Blood Coagulation; Female; Humans; Lipoproteins; Male; Middle Aged; Platelet Aggregation Inhibitors; Platelet Count; Platelet Factor 4; Quinazolines; Thrombocythemia, Essential; Thrombosis

Topics: Adolescent; Adult; Anemia; Cohort Studies; Follow-Up Studies; Hemorrhage; Humans; Hydroxyurea; Incidence; Middle Aged; Quinazolines; Risk; Thrombocythemia, Essential; Thrombophilia; Thrombosis

Anagrelide is a novel platelet-lowering agent that has recently been approved for use in essential thrombocythemia (ET) and related disorders. Short-term drug efficacy and toxicity data have previously been presented. The purpose of this study was to obtain additional information regarding long-term anagrelide use. This is a retrospective series of 35 young patients (17 to 48 years) with ET who received anagrelide treatment before 1992. Initial drug dosage ranged between 1 and 10 mg/d, and the median maintenance dosage was 2.5 mg/d. The overall initial response rate of 94% included 74% complete remissions and 20% partial remissions. Of the 33 responding patients, 27 (82%) remained on anagrelide therapy for a median of 10.8 years (range, 7 to 15.5). Of these, 66% maintained a complete and 34% a partial remission over the study period. In general, the reporting of somatic side effects decreased over time, and anemia was the only new side effect that emerged after long-term therapy. Eight patients (24%) experienced a more than 3 g/dL decrease in hemoglobin level. Despite active therapy, 20% of the patients experienced a total of 10 thrombotic episodes, and a similar proportion experienced major hemorrhagic events. All thrombohemorrhagic complications occurred at a platelet count of more than 400 x 10(9)/L. It is concluded that long-term treatment of ET with anagrelide is associated with decreased reporting of initial side effects and the development of mild-to-moderate anemia. Complete normalization of platelet counts may be needed to minimize residual thrombohemorrhagic risk during therapy. (Blood. 2001;97:863-866)

Topics: Adolescent; Adult; Female; Hemorrhage; Humans; Male; Middle Aged; Platelet Aggregation Inhibitors; Quinazolines; Remission Induction; Retrospective Studies; Thrombocythemia, Essential; Thrombosis; Treatment Outcome

Two series of 1,3-dihydro-2H-imidazo[4,5-b]quinolin-2-one derivatives incorporating an additional site for acid salt formation were synthesized and evaluated as inhibitors of human blood platelet cAMP phosphodiesterase (PDE) and ADP-induced platelet aggregation. The objective of this study was to identify compounds that blended potent biological activity with a satisfactory level of aqueous solubility. From a series of 7-aminoimidazo[4,5-b]quinolin-2-ones, biological and physical properties were optimally combined in the 1-piperidinyl derivative 11c. However, this compound offered no significant advantage over earlier studied compounds as an antithrombotic agent in an animal model of small vessel thrombosis. A series of 7-alkoxy alkanoic piperazinamide derivatives, in which the additional basic nitrogen atom was remote from the heterocyclic nucleus and accommodated in a secondary binding region of the cAMP PDE enzyme, demonstrated greater intrinsic cAMP PDE inhibitory activity. Structural modifications of this series focused on variation of the piperazine substituent and side-chain length. The lipophilicity of the N-substituent influenced biological potency and aqueous solubility, with substituents of seven carbon atoms or less generally providing acceptable solubility properties. The N-(cyclohexylmethyl)piperazinamide 21h was identified from this series of compounds as a potent inhibitor of platelet cAMP PDE, IC50 = 0.4 nM, and ADP-induced platelet aggregation, IC50 = 0.51 microM after a 3-min exposure and 0.1 microM after a 15-min exposure of platelet-rich plasma to the drug. Evaluation of 21h and representative analogues in vivo using a rabbit model of small vessel thrombosis revealed significantly greater antithrombotic efficacy compared to that of previously studied compounds with similar intrinsic biological activity measured in vitro but inferior aqueous solubility.

Topics: 3',5'-Cyclic-AMP Phosphodiesterases; Animals; Blood Platelets; Humans; Imidazoles; Quinolones; Rabbits; Solubility; Thrombosis

Essential thrombocythemia is typically a disorder of adults in the sixth or seventh decade of life and is characterized by frequent thrombohemorrhagic complications. In young patients, the optimal management of complications is controversial. We studied 56 young adults (33 female and 23 male patients) with a diagnosis of essential thrombocythemia. The mean duration of follow-up was 4.68 years. The mean platelet count at diagnosis was 1,328,000/mm3. Platelet aggregation studies in 21 patients demonstrated hypoaggregation to epinephrine; spontaneous platelet aggregation was present in 4. At diagnosis, 39 patients were asymptomatic, and thrombocytosis was discovered incidentally. Throughout follow-up (up to 20 years), 24 patients remained asymptomatic. Thrombotic complications developed in 24 patients; they were life-threatening in only 3. The most common vaso-occlusive symptoms were migraine headache (in 12 patients) and erythromelalgia (in 3). Minor hemorrhagic complications occurred in six patients, and none was life-threatening. Serious complications (one cerebral and two myocardial infarctions) occurred in three patients, all of whom recovered. Two deaths occurred, neither of which was attributable to essential thrombocythemia. The treatment regimens used were chemotherapy in 9 patients, antiaggregating agents in 7, radioactive phosphorus in 1, the newer platelet-lowering agent anagrelide in 10, and only observation in 29. No treatment-related acute leukemias developed. This series of young patients with essential thrombocythemia, the largest to date, demonstrates a low incidence of life-threatening complications and a favorable long-term prognosis. Therapeutic recommendations should remain conservative, and potential leukemogens should be avoided unless serious complications develop. Anagrelide may be useful in young patients with thrombocythemia who are symptomatic.

Topics: Adolescent; Adult; Child; Epinephrine; Female; Follow-Up Studies; Humans; Male; Platelet Aggregation; Platelet Aggregation Inhibitors; Platelet Count; Prognosis; Quinazolines; Retrospective Studies; Thrombocythemia, Essential; Thrombosis

Topics: Adenosine Diphosphate; Animals; Carotid Arteries; Collagen; Dogs; Electricity; Fibrinolytic Agents; Haplorhini; Hemorrhage; Humans; Imidazoles; Lasers; Macaca mulatta; Platelet Aggregation; Quinazolines; Rabbits; Rats; Thrombosis