Continuous infusion of recombinant factor VIII formulated with sucrose in surgery: non-interventional, observational study in patients with severe haemophilia A.

In haemophilia A, continuous infusion (CI) of FVIII perioperatively provides a more constant FVIII level than conventional bolus injections, avoiding low trough levels that could increase bleeding risk. Due to the low number of surgical cases in clinical trials, especially in haemophilia, more information on the clinical practice of CI from observational studies is helpful. We aimed to evaluate the effectiveness and safety of CI with recombinant factor VIII formulated with sucrose (rFVIII-FS) in a typical surgery practice setting. This was a non-interventional study in 12 centres. Patients with severe haemophilia A who received rFVIII-FS by CI during and after surgery were included in this study if they had more than 150 exposure days (EDs) to any FVIII product and had no history of inhibitors before CI. Patients were observed during the entire course of CI, with monitoring up to 3 months thereafter. Twenty-five patients with 28 surgeries were included in the analysis. Median age was 51.7 (range 10-75). Most (75%; 21/25) patients underwent orthopaedic surgeries. The median dose of rFVIII-FS consumed during CI was 376 IU kg(-1) (range 157.9-3605.6 IU kg(-1)) with a greater median dose for orthopaedic surgeries (424.0 IU kg(-1)) compared to non-orthopaedic surgeries (278.5 IU kg(-1)). 95% of all FVIII measurements (214/224) were on target. Efficacy and tolerability were rated as good/excellent in 89.3% (25/28) of surgeries. No inhibitors were observed during or after surgery. This study demonstrates the effectiveness of CI with rFVIII-FS during surgery in patients with severe haemophilia A in a clinical practice setting.

Efficacy and safety during formulation switch of a pasteurized VWF/FVIII concentrate: results from an Italian prospective observational study in patients with von Willebrand disease.

Von Willebrand disease (VWD) is an inherited bleeding disorder caused by the quantitative or qualitative deficiency of von Willebrand factor (VWF). Replacement therapy with plasma-derived VWF/factor VIII (FVIII) concentrates is required in patients unresponsive to desmopressin. To assess the efficacy, safety and ease of use of a new, volume-reduced (VR) formulation of VWF/FVIII concentrate Haemate(®) P in patients requiring treatment for bleeding or prophylaxis for recurrent bleeding or for invasive procedures. Pharmacoeconomic variables were also recorded. Data were analysed using descriptive statistics. This was a multicentre, prospective, observational study. Consecutively enrolled patients received Haemate(®) P VR according to their needs, and were followed for 24 months. Of the 121 patients enrolled, 25.6% had type 3 VWD and more than 40% had severe disease. All patients were followed for 2 years, for a total of 521 visits. On-demand treatment was given to 61.9% of patients, secondary long-term prophylaxis to 25.6% and prophylaxis for surgery, dental or invasive procedures to 45.5%. The response to treatment was rated as good to excellent in >93-99% of interventions. The new formulation was well tolerated by all patients with no report of drug-related adverse events. The switch to volume-reduced Haemate(®) P was easy to perform and infusion duration was decreased twofold compared with the previous formulation. Volume-reduced Haemate(®) P was at least as effective and well-tolerated as the previous formulation.

Forum on: the role of recombinant factor VIII in children with severe haemophilia A.

The development of recombinant FVIII (rFVIII) products, fuelled by the need for improved safety of treatment arising from the dramatic widespread blood-borne virus transmission in the 1970-1980s revolutionized the care of children with haemophilia A over the last two decades. The larger availability of perceived safer replacement therapy associated with the introduction of rFVIII products reassured the haemophilia community and there was a strong push in some Western countries to treat haemophilic children only with rFVIII. Moreover, this significantly contributed in the 1990s to the diffusion outside Northern Europe of prophylactic regimens implemented at an early age to prevent bleeding and the resultant joint damage (i.e. primary prophylaxis), together with the possibility of home treatment. These changes led to a substantial improvement of the quality of life of haemophilic children and of their families. The general agreement that primary prophylaxis represents the first-choice treatment for haemophilic children has been recently supported by two randomized controlled trials carried out with rFVIII products, providing evidence on the efficacy of early prophylaxis over on-demand treatment in preserving joint health in haemophilic children. However, the intensity and optimal modalities of implementation of prophylaxis in children, in particular with respect to the issue of the venous access, are still debated. A number of studies also supports the role of secondary prophylaxis in children, frequently used in countries in which primary prophylaxis was introduced more recently. With viral safety now less than an issue and with the more widespread use of prophylaxis able to prevent arthropathy, the most challenging complication of replacement therapy for children with haemophilia remains the risk of inhibitor development. Despite conflicting data, there is no evidence that the type of FVIII concentrate significantly influences the complex multifactorial process leading to anti-FVIII alloantibodies, whereas other treatment-related factors are likely to increase (early intensive treatments due to surgery or severe bleeds) or reduce (prophylaxis) the risk. Although the optimal regimen is still uncertain, eradication of anti-FVIII antibodies by immune tolerance induction (ITI), usually with the same product administered at inhibitor detection, should be the first-choice treatment for all patients with recent onset inhibitors. This issue applies particularly to children, as most patients undergo ITI at an early age, when inhibitors usually appear. The availability of a stable and long-lasting venous access represents a leading problem also in this setting. These and other topics concerning rFVIII treatment of haemophilic children were discussed in a meeting held in Rome on 27 February 2008 and are summarized in this report.

Studies on mechanisms involved in hypoglycemia-induced platelet activation.

The aim of our study was to investigate the mechanisms involved in hypoglycemia-induced platelet activation. Sixteen healthy male subjects received a 60-min intravenous infusion of human regular insulin at the rate of 64 mU . m-2 . min-1: throughout 150 min, we serially measured plasma concentrations of glucose, insulin, and counterregulatory hormones; platelet sensitivity to ADP, thrombin and platelet-activating factor; plasma concentrations of platelet markers for specific proteins of in vivo release reaction (beta-thromboglobulin and platelet factor 4). Our study showed that insulin-induced hypoglycemia causes a significant increase in platelet sensitivity to aggregating agents in vitro and a platelet release reaction in vivo. Hypoglycemia-induced platelet activation was not correlated with plasma glucose concentrations at nadir and occurred before the increase of plasma growth hormone and cortisol. To further elucidate the mechanisms of hypoglycemia-induced platelet activation, we incubated in vitro platelet-rich plasma (PRP) of seven fasting healthy subjects with the same concentrations of insulin, epinephrine, glucagon, growth hormone, and cortisol measured in vivo during insulin-induced hypoglycemia. Only epinephrine was able to increase platelet sensitivity to aggregating agents. To investigate the role of alpha-adrenergic receptors in this phenomenon, we also studied four healthy subjects on another occasion, repeating the above-described insulin infusion together with intravenous infusion of phentolamine (-15 to +150 min), 5 mg over 2 min followed by 500 micrograms/min. alpha-Blockade was able to suppress hypoglycemia-induced increase of platelet sensitivity to aggregating agents.(ABSTRACT TRUNCATED AT 250 WORDS)

A randomized clinical trial of high-intensity warfarin vs. conventional antithrombotic therapy for the prevention of recurrent thrombosis in patients with the antiphospholipid syndrome (WAPS).

BACKGROUND: The optimal intensity of oral anticoagulation for the prevention of recurrent thrombosis in patients with antiphospholipid antibody syndrome is uncertain. Retrospective studies show that only high-intensity oral anticoagulation [target international normalized ratio (INR) >3.0] is effective but a recent randomized clinical trial comparing high (INR range 3.0-4.0) vs. moderate (INR 2.0-3.0) intensities of anticoagulation failed to confirm this assumption. METHODS: We conducted a randomized trial in which 109 patients with antiphospholipid syndrome (APS) and previous thrombosis were given either high-intensity warfarin (INR range 3.0-4.5, 54 patients) or standard antithrombotic therapy (warfarin, INR range 2.0-3.0 in 52 patients or aspirin alone, 100 mg day(-1) in three patients) to determine whether intensive anticoagulation is superior to standard treatment in preventing symptomatic thromboembolism without increasing the bleeding risk. RESULTS: The 109 patients enrolled in the trial were followed up for a median time of 3.6 years. Mean INR during follow-up was 3.2 (SD 0.6) in the high-intensity warfarin group and 2.5 (SD 0.3) (P < 0.0001) in the conventional treatment patients given warfarin. Recurrent thrombosis was observed in six of 54 patients (11.1%) assigned to receive high-intensity warfarin and in three of 55 patients (5.5%) assigned to receive conventional treatment [hazard ratio for the high intensity group, 1.97; 95% confidence interval (CI) 0.49-7.89]. Major and minor bleeding occurred in 15 patients (two major) (27.8%) assigned to receive high-intensity warfarin and eight (three major) (14.6%) assigned to receive conventional treatment (hazard ratio 2.18; 95% CI 0.92-5.15). CONCLUSIONS: High-intensity warfarin was not superior to standard treatment in preventing recurrent thrombosis in patients with APS and was associated with an increased rate of minor hemorrhagic complications.

Natural history and risk factors for thrombosis in 360 patients with antiphospholipid antibodies: a four-year prospective study from the Italian Registry.

PURPOSE: To assess the natural history and risk factors for thrombosis in a large cohort of unselected patients with antiphospholipid antibodies. PATIENTS AND METHODS: Three hundred sixty consecutive patients (118 males, 242 females, median age 39 years [range 2 to 78]) fulfilling the currently accepted criteria for diagnosis of lupus anticoagulant (LAC) (n = 326) and/or raised immunoglobulin G anticardiolipin antibodies (IgG ACA) (n = 185) were collected from 16 Italian institutions and prospectively observed for a median of 3.9 years (range 0.5 to 5). Main endpoints were the occurrence of arterial or venous thrombosis, the outcome of pregnancies, and any severe complications leading to hospitalization or death. RESULTS: Thirty-four patients developed a thrombotic complication, with a total incidence of 2.5% patient-years. Multivariate logistic regression analysis identified two independent risk factors for thrombotic events: a previous thrombosis (RR 4.9; 95% CI, 1.76 to 13.7; P < 0.005) and IgG ACA titer above 40 units (RR 3.66; 95% CI, 1.24 to 10.8; P < 0.01). A total of 28 pregnancies were observed in 25 women and 11 (39%) were abortive. Adverse pregnancy outcomes were significantly more frequent in women with a history of miscarriage or vascular occlusion (9/16, 56%) than in asymptomatic women (2/12, 17%) (P = 0.035). Four patients developed non-Hodgkin's lymphoma during the follow-up. Eighteen patients died. Vascular events and hematological malignancies represented the most frequent causes of death (n = 5 for each). CONCLUSIONS: The present study shows that: (a) previous thrombosis and ACA titer > 40 U are independent predictors of thrombosis; (b) history of miscarriage or vascular disease is significantly associated with adverse pregnancy outcome; (c) hematological malignancies can develop during follow-up in patients with antiphospholipid antibodies.

Use of modified functional assays for activated protein C resistance in patients with basally prolonged aPTT.

Inherited resistance to activated protein C (APCr) is currently recognized as the most prevalent cause underlying venous thrombophilia, with an estimated prevalence around 20% in thrombotic patients and around 1.8-7% in the general population. A correct laboratory diagnosis of APCr is therefore essential. Two different diagnostic approaches are at present at our disposal: the semi-quantitative plasma test based on the measurement of two aPTTs (in the presence and absence of activated protein C), and the detection of the factor V Arg506 Gln mutation by DNA analysis. In this study we firstly evaluated sensitivity, specificity and diagnostic efficiency of an aPTT-based plasma clotting test (Chromogenix, Sweden) versus DNA analysis; then, since the APC resistance test is invalidated by a basally prolonged aPTT (i.e. during warfarin and heparin therapy or in patients with clotting factor deficiencies or in the presence of a lupus anticoagulant), patient plasmas were conveniently diluted in factor V deficient plasma in order to correct clotting factor abnormalities. Nevertheless, patients with a LA and an aPTT ratio range 1.8-3.17 were still all misclassified. We obtained correct diagnoses in LA positive patients by preincubating plasmas with a mixture of phospholipids; therefore we decided to perform a double modified clotting test adding a mixture of platelet derived phospholipids to samples previously diluted in factor V deficient plasma. The performance characteristics of this novel method with a different aPTT reagent (Behring, Germany) were also evaluated. With this double modified test all patients were correctly classified as negative or positive for factor V mutation in agreement with DNA analysis, irrespectfully of the basal aPTT value and the aPTT reagent employed. We propose this modified version of the APCr clotting test as an easily reproducible, reliable, very sensitive and specific screening test which possibly reduces the need for DNA analysis.

Congenital deficiency of alpha-2-adrenoceptors on human platelets: description of two cases.

The biochemistry and functionality of platelets from two related subjects (mother and son) with alpha-2-adrenoceptor-deficient platelets has been evaluated. Radioligand binding experiments with the specific alpha-2-adrenergic-receptor antagonist, 3H-yohimbine, showed a drastic reduction of alpha-2-adrenoceptors in platelets from both subjects in comparison with the control values. Electron microscopy studies revealed a normal morphology and a normal number of alpha granules and dense bodies. Levels of adenine nucleotides; 5-hydroxytryptamine; B-thromboglobulin; platelet-factor-4 and thromboxane A2 production were within normal limits. Platelet aggregation and 5-hydroxytryptamine production in response to adrenalin (at concentrations up to 50 microM) were absent, whereas ADP, AA, PAF, collagen and thrombin-induced aggregation, secretion, Ca++ flux and thromboxane A2 production were normal. The inhibitory effect caused by different concentrations of prostacyclin on Ca++ flux, aggregation, secretion and thromboxane A2 production of platelet functionally lacking of alpha-2-adrenoceptor was not distinguishable from control platelets and platelets preincubated with yohimbine.

Combined differentiating therapy for myelodysplastic syndromes: a phase II study.

An in vitro synergism between different inducers of AML cell differentiation has been previously observed. Therefore, we treated 53 myelodysplastic (MDS) patients with a low dose combination of cis-retinoic acid (cRA, 20-40 mg/day) and 1,25 alpha (OH)2 cholecalciferol [(OH)2D3, 1-1.5 micrograms/day] +/- intermittent 6-thioguanine (30 mg/m2/day). The latter was reserved for patients with bone marrow (BM) blast excess (> or = 5%). The treatment was well tolerated, without major toxicity. Among 25 patients with BM blasts less than 5%, we observed one complete, eight partial and four minor responses (response rate 52%) with a median response duration of 8 months (2 +/- 24). Median survival, which did not correlate with response, is projected at 76 months. Thirty-one patients with BM blast excess (> or = 5%), including three of the previous group who progressed to refractory anemia with excess of blasts (RAEB), were treated with the three-drug protocol. One complete, 12 partial and six minor responses were obtained (response rate 61%) with a median response duration of 6 months (2-29+). A significant difference in survival (P < 0.005) was observed between the 19 responders (median 25 months) and the 12 non-responders (median 9 months). A reduction in the transfusion need was observed in 41% of the transfusion-dependent patients with blast excess and in 53% of those without blast excess. Therefore, combined differentiating therapy seems more effective than previously reported single agent treatments and should be considered for a larger randomized study to assess its actual impact on survival of MDS patients.

Absence of (-) [3H]desmethoxyverapamil binding sites on human platelets and lack of evidence for voltage-dependent calcium channels.

The two major pathways for Ca2+ entry into cells are potential-sensitive channels and receptor-operated channels. The main object of this investigation was to identify which mechanism regulates Ca2+ entry into human platelets. Platelet stimulation with thrombin, adenosine diphosphate, platelet activating factor and arachidonic acid resulted in a concentration-dependent 2.5-3-fold increase in cytoplasmic free calcium concentration over the basal levels (140 +/- 32 nM or 104 +/- 21 respectively) as measured with the fluorescent dyes Quin-2 and Fura-2. Adrenaline and collagen had no effect in promoting intracellular Ca2+ increase as measured with Quin-2 and little effect when measured with Fura-2. Incubation of Quin-2-loaded platelets with the calcium antagonists verapamil and diltiazem, which are known to inhibit Ca2+ entry from voltage-gated channels in many types of cells, over the concentration range 10(-8) - 10(-4) M did not alter significantly either the resting or the cytoplasmic free Ca2+ after stimulation of platelets by several agonists. Moreover, the calcium antagonists exhibited little or no effect on aggregation and 5-hydroxytryptamine secretion induced by platelet activating factor, adenosine diphosphate, collagen or arachidonic acid in whole blood, platelet-rich plasma or washed platelets when employed at concentration ranges as above. Similar results were obtained in washed thrombin-stimulated platelets. High doses of verapamil (but not diltiazem) inhibited platelet aggregation and secretion in response to adrenaline. Direct radioligand binding studies with (-)[3H]desmethoxyverapamil showed that platelet membranes have no receptors for this drug, suggesting that Ca2+ entry occurs in human platelets via a pathway different from potential-sensitive Ca2+ channels.(ABSTRACT TRUNCATED AT 250 WORDS)

Paraproteinaemias and platelet aggregation: role of whole blood aggregometry.

Whole blood and optical platelet aggregation were measured in normals and in patients with paraproteinaemias; extent of aggregation was correlated with paraprotein concentrations in patients and in normals after addition of different doses of paraproteins; threshold aggregating concentrations of several agonists were also determined in whole blood and in PRP from both groups of subjects. The results indicate that patients with macromolecular monoclonal component bear a "hyperaggregable" state which can be probably ascribed also to plasma hyperviscosity and which is better detected with the impedance aggregometer.

Lupus anticoagulant and thrombosis: role of von Willebrand factor multimeric forms.

OBJECTIVE: Patients with lupus anticoagulant (LA) have an increased incidence of venous and arterial thrombosis whose pathogenesis is still unclear. High molecular weight von Willebrand Factor (vWF) multimers seem to play a causal role in shear stress-induced platelet aggregation and thrombus formation. We studied whether in patients with LA, alterations in the vWF multimers might coexist. METHODS: The multimeric composition of plasma vWF was analysed by SDS-electrophoresis and immunoblotting in 43 subjects positive for LA. About 2/3 of the patients had had either ischemic stroke, recurrent abortions, deep vein thrombosis (DVT) or a combination of these; the remaining subjects had never had any thrombotic events. RESULTS: An abnormal vWf multimeric pattern was found in 16 patients (37.2%); no correlation was found with the diagnosis, but the presence of abnormal vWF significantly correlated with the site of the thrombosis: indeed, it was never detected in subjects with DVT, but was found in 71.4% of patients with multiple abortions, in 50% of those with stroke and even in 25% of non-thrombotic patients. CONCLUSION: The hypothesis is put forward that abnormal VWF may represent an additional risk factor to LA for arterial thrombosis.

Cancers in patients with hemophilia: a retrospective study from the Italian Association of Hemophilia Centers.

BACKGROUND: The increased life expectancy of the hemophilia population, primarily as a result of advances in factor replacement therapy, has enabled hemophiliacs to reach an older age. Consequently, age-related diseases, such as cardiovascular disorders and cancers, are being increasingly recognized in such patients. However, only few data are available on such co-morbidities, their management and impact on the primary bleeding disorders. OBJECTIVES: With the aim of investigating several still unclear issues regarding cancers in hemophilia patients, we conducted, on behalf the Italian Association of Hemophilia Centers (AICE), a study on cancers among Italian hemophiliacs. PATIENTS: Data pertaining to 122 hemophiliacs with 127 cancers between 1980 and 2010 were retrospectively collected in 21 centers of the AICE which chose to participate. RESULTS: Sixty-nine percent of cancers were recorded during the decade 2001­2010. Eighty-three percent of patients were infected with hepatitis C virus (HCV) and 22% of them were also co-infected with human immunodeficiency virus (HIV). Forty-three percent of cancers were HCV-related, whereas 9%were HIV related. Virus-related cancers were more frequent and non-virus-related cancers less frequent in patients with severe hemophilia than in those with mild/moderate forms (P = 0.0004). The non-virus-related standardized mortality ratio (SMR) was 0.3. Hemorrhagic complications occurred more frequently in patients undergoing chemotherapy (14%) or radiotherapy (19%). CONCLUSIONS: The results of the present study confirm that cancers have become a new challenge for physicians working in hemophilia centers and underline the need for prospective trials to better assess the epidemiology and to optimize the management of hemophiliacs with cancer.

In vivo platelet activation in lower limbs thrombophlebitis. A longitudinal study.

Platelet activation in vivo was studied in patients with thrombophlebitis of the lower limbs. The parameters considered were the platelet aggregate ratio (PAR) and the beta-thromboglobulin (beta-tg) level, which were repeatedly evaluated from the disease onset up to 3 months later, during anticoagulating and antiaggregating therapy. A significant decrease of PAR was found, along with a significant rise of the beta-tg level at the onset of the disease, and these values slowly returned to normal on therapy course. The same parameters exceeded the normal range again when the patients arbitrarily suspended any drug assumption. The possible significance and implications of these findings are discussed.

Thrombosis-free survival and life expectancy in 187 consecutive patients with essential thrombocythemia.

A total of 187 consecutive patients with essential thrombocythemia (ET) were diagnosed and followed by our Hematology Department in the period October 1980-November 1994. The overall follow-up was 773 patient-years. Thrombosis-free survival and overall survival were calculated for the whole cohort; the same parameters were then calculated after arbitrary division of the cohort into two groups, according to the median age at diagnosis (55 years). Fifty percent of the patients had at least one thrombotic episode within 9 years after diagnosis. The thrombosis-free survival curves calculated for patients younger or older than 55 years at diagnosis were comparable. About 85% of the patients were alive 10 years after diagnosis. The survival curves for patients younger and older than 55 years at diagnosis were not significantly different in the observation period, and the observed mortality (seven patients) among patients younger than 55 years at diagnosis was significantly higher than expected (1.68 cases). The relative risk of death was four times greater (SMR = 4.17, 95% C.I. 1.6-8.6, p<0.01) than for healthy, age-matched people living in the same area. Age at diagnosis, smoking, sex, hypercholesterolemia, peak number of platelets, hypertension, and diabetes were not significant prognostic cardiovascular risk factors in our cohort. In conclusion, our data show that ET has to be considered a serious disease that significantly decreases both quality of life (expected life without thrombosis) and life expectancy for younger patients.

No evidence of platelet activation during atrial pacing in subjects with stable angina.

Platelet behaviour (activation) in ischemic heart disease (stable angina) during pacing-induced tachycardia was studied. ECG was recorded during the trial. Ischemic heart disease (IHD) subjects had 75% or more narrowing of the luminal diameter of a coronary artery, demonstrated by coronary angiography. Eight subjects needing cardiac catheterism because of supraventricular rhythm disturbances with no evidence of IHD were studied as controls. Beta-thromboglobulin (beta-tg) and platelet factor 4 (PF4) were studied as platelet activation markers; beta-tg and PF4 were evaluated before atrial pacing in peripheral venous blood and, by catheterism, before and at maximum pacing rate in coronary venous sinus (CVS) and in ascending aorta (AA). Catheterism and blood withdrawals were performed in order to reduce platelet activation in vivo. No significant difference in platelet activation between IHD patients and control group in peripheral venous blood were found. No trans-myocardial gradient neither in IHD subjects nor in controls were observed. In conclusion, no platelet activation in IHD patients during pacing-induced tachycardia could be observed.