Factor VII Coagulant Activity Research Articles

The expanding role of prophylaxis with recombinant activated factor VII.

The expanding role of prophylaxis with recombinant activated factor VII.

Rationaler Einsatz von Blutprodukten - Reduzierung des Blutprodukteverbrauchs durch ein modernes Gerinnungsmanagement

Evaluating the patient's individual bleeding history with a standardized questionnaire, using "point-of-care" - methods for coagulation analyses and providing autologous transfusion techniques are preconditions of a modern coagulation management. Therapy of coagulopathic patients should be based on structured hemotherapy algorithms. Surgical haemostasis and the maintenance of the basic conditions for haemostasis are elementary requirements for an effective therapy. In cases of diffuse bleeding, early antifibrinolytic therapy should be considered. Coagulation factor deficiencies should be corrected "goal-directed" using coagulation factor concentrates. Transfusion of fresh frozen plasma is only indicated in the clinical setting of massive transfusions. DDAVP and transfusion of platelet concentrates are options to optimize primary haemostasis. In cases of on-going bleeding, recombinant activated coagulation factor VII represents an option for "ultima-ratio" therapy.

Elevated circulating tissue factor procoagulant activity, factor VII, and plasminogen activator inhibitor‐1 in childhood obesity: evidence of a procoagulant state

Childhood obesity is rapidly increasing in prevalence. We compared circulating membrane-bound tissue factor (FIII, F3) procoagulant activity (TF-PCA) and plasma markers of coagulation, fibrinolysis and endothelial dysfunction in 21 obese (10·1 ± 1·5 years, mean ± standard deviation) and 22 healthy weight children (9·9 ± 1·6 years), classified by Body Mass Index (BMI). TF-PCA and factor VII coagulant activity (FVII:C), plasminogen activator inhibitor (PAI-1, SERPINE1) and soluble vascular cell adhesion molecule 1 (sVCAM1) were higher in obese children. BMI correlated positively with TF-PCA, FVII:C, and PAI-1. Childhood obesity is associated with a procoagulant state and endothelial dysfunction. Studies are needed to assess whether weight reduction reverses these abnormalities.

Recombinant factor VIIa as last‐resort treatment of desperate haemorrhage

Studies are inconclusive regarding clinical outcomes after administration of recombinant activated coagulation factor VII (rFVIIa) during severe haemorrhage. The circumstances encountered during desperate haemorrhage make it difficult to include the most critically ill patients that could possibly benefit the most from such treatment into randomized controlled trials. We report our experience with rFVIIa as last-resort treatment of desperate haemorrhage when all standard treatment has failed. Hospital charts of all consecutive patients treated with rFVIIa for desperate non-haemophilic bleeding over a 10-year period at the single institution administering rFVIIa were surveyed for treatment indications, clinical outcome, transfusion need and coagulation profiles. Fifty-five rFVIIa treatment occasions of desperate bleeding were identified in 54 patients (median age 54 years). A single rFVIIa dose was used in 86%, and haemorrhage was considered effectively contained by immediate clinical response on 81% of occasions. Overall, 38 patients (71%) survived for over 30 days. Two thromboembolic events occurred (3.6%). The 24-h mortality in 45 rFVIIa immediate clinical responders and 10 non-responders was 2% and 50%, respectively (P = 0.0004), and the 30-day mortality was 25% and 60%, respectively (P = 0.05). Blood product use decreased with rFVIIa (P < 0.01) as did the prothrombin time (20.0-13.3 s, P < 0.0001). The majority of unselected consecutive patients receiving rFVIIa as last-resort treatment for desperate haemorrhage were considered to have immediate clinical response as well as reduced transfusion requirements and correction of coagulation parameters. An immediate clinical response to rFVIIa may possibly be predictive of survival.

Hemostatic properties of the FVIIa analog NN1731

Recombinant activated coagulation factor VII (rFVIIa) has proven to be a useful prohemostatic agent in patients with hemophilia and antibody inhibitors. It has also been used off-label in other settings. A major mechanism of its hemostatic efficacy is its ability to activate factor X on the surface of activated platelets in a tissue factor (TF)-independent manner. Novel analogs of FVIIa have been designed to have greater platelet-surface activity in the hope that these will be more active and reliable hemostatic agents. The analog NN1731 (vatreptacog alfa) was designed to have greater activity in the absence of TF, with the same substrate specificity as FVIIa. Surprisingly, it also binds to a greater number of sites on activated platelets by an, as yet, unknown mechanism. This molecule exhibits greater potency than FVIIa in biochemical assays, in vitro and animal models, and in early phase clinical trials.

Replacement Therapy for Minor Surgery and Invasive Procedures in Factor VII Deficiency: The STER Experience

Abstract 1262 Introduction:Surgical bleeding is among the most frequent symptoms in Factor VII (FVII) deficient patients: in an analysis by our group, post-surgical bleeding was reported in 24% of cases (Mariani G. et al. Thromb Haemost 2005;93:481). A recent retrospective study showed a similar prevalence of surgical bleeding (15%) with a significant relation between this type of bleeding, deep hematomas and a FVII coagulant activity (FVIIc) of less than 7% (Benlakal F et al. J Thromb Haemost 2011;9:1149). Little is known about prevention of bleeding in ‘minor surgical interventions', important tools in modern medicine, bearing not a negligible risk of bleeding, as local hemostasis may not always be punctually achieved. Aim:Analysis of Replacement Therapy (RT) for minor surgeries in patients with FVII deficiency, prospectively reported in the Seven treatment Evaluation Registry (STER). Clinicaltrials.gov identifier: NCT01269138. Methods:Analysis of RTs used in 38 minor surgical procedures (34 patients; FVIIc:<1–20%). Minor surgical procedures were defined as suggested by Kitchens (Surgery and hemostasis. Textbook of Consultative Hemostasis and Thrombosis. 2007). Results:Reported interventions included: oral surgery (n=15), endoscopic biopsies (n=7), catheter insertions (n=3), ear-nose-throat and head-neck (n=5), mixed type (n=8). RT schedules were based on recombinant-activated FVII (rFVIIa; n=29), plasma-derived FVII (pdFVII; n=8), or Fresh-Frozen-Plasma (n=1). One-day RT schedule was employed in 27 procedures, 2–10 days in 11 procedures. Total doses ranged from 7.2–510 μg/kg (rFVIIa) and 9–300 IU/kg (pdFVII). FFP was given at a total dose of 50 ml/kg (1-day treatment, split into 4 doses of 12.5 ml). Antifibrinolytics were administered together with RT in 16 procedures (11 dental) for a minimum of 1 day to a maximum of 7 days. No bleeding nor thrombotic events occurred; one patient developed an inhibitor (Table 1).Table 1Type of intervention, replacement therapy schedules and outcomeMinor Surgery ProceduresnReplacement Therapy (RT)RT daysTotal n. of dosesTotal dose μg/Kg IU/KgAnti- FibrinolyticsAdverse eventsOral Surgery + Multiple extractions8rFVIIa 7 pdFVII 11–42–10rFVIIa 19–60 pdFVII 9.35/8Inhibitor (1 case)Single extractions7rFVIIa 6 pdFVII 111–2rFVIIa 14–110 pdFVII 3006/7NOENT and Head & Neck5rFVIIa 4 pdFVII 11–101–16rFVIIa 7.2–510 pdFVII 1122/5NOCatheters3pdFVII 2 FFP 111–4pdFVII 18–29 FFP 50 ml/KgNONOEndoscopic biopsies7rFVIIa 711–7rFVIIa 10–3002/7NOMixed8rFVIIa 5 pdFVII 31–91–16rFVIIa 15–60 pdFVII 60–3701/8NO Conclusion:For most of the uncomplicated minor surgery procedures (single dental extractions, catheter insertions, endoscopic biopsies), one-day RT is sufficient with low to medium doses of rFVIIa (median 25 μg/Kg/bw) or pdFVII (median 18.5 UI/Kg/bw), possibly with more than one administration. In complicated and more elaborate interventions, longer-lasting RT schedules and higher doses may be needed. Disclosures:No relevant conflicts of interest to declare.

Management of the Sponataneous Bleeding Episodes in Factor VII Deficiency. A Prospective Evaluation of the STER,

Abstract 3368 IntroductionPatients with an inherited factor VII (FVII) deficiency may display a wide range of clinical phenotypes, from an asymptomatic condition to serious hemorrhagic episodes such as fatal central nervous system (CNS) or gastrointestinal (GI) bleeds (Mariani G et al. Thromb Haemost 2005; 93: 481–7). Symptomatic patients can be divided into two major categories: those with mild-to-moderate bleeding tendency and individuals with a severe bleeding tendency which may be more severe than that in hemophilia. The former group mainly experience mucosal bleeding, a clinical picture that mimics that of a platelet disorder and often does not call for treatment. In contrast, for the most severely affected patients, characterized by life- or limb-threatening hemorrhages, more aggressive Replacement Therapy (RT) as long or short-term prophylxis may be required. AimWithin the frame of the Seven Treatment Evaluation Registry we have prospectively collected large numbers of treatments for spontaneous bleeding episodes and evaluted schedules and side-effects. Clinicaltrials.gov identifier: NCT01269138. ResultsAs of May 2011, 64 evaluable spontaneous bleedings (managed in 16 haemophilia treatment centres, 11 countries), were observed in 40 FVII-deficient subjects (25 females and 15 males) with residual FVII coagulant activity (FVIIc) levels between <1% and 20% (90% of patients had FVIIc below 5% of normal). Bleeding episodes were grouped into the following categories: 1. CNS + GI (n=2+4), 2. Hemarthroses (n=23), 3. Muscle hematomas (n=6), Epistaxis (n=4), Gum bleeding (n=7), Menorrhagia (n=11), Other (n=7) (hemorrhoidal n=2, subcutaneous hematomas n=2, easy bruising n=1, hematuria n=1, hemoperitoneum n=1). Recombinant FVIIa was given to treat 47 episodes, plasma derived FVII (pdFVII) concentrates 7, Prothrombin Complex Concentrate (PCC) 3 and Fresh Frozen Plasma (FFP) 7 (Table 1). No thrombosis episodes were reported during the thirty-day follow up.Table 1Type of Bleeding, Replacement Therapy (RT) schedules and outcomeBleedsnRTRT daysn. of dosesTotal dose range (μg/Kg IU/Kg ml/Kg)OutcomeCNS & GI6rFVIIa 31–41–8rFVIIa 160-240median 160Excellent 1 P.Effective 2pdFVII 2pdFVII 15-60–P.Effective 1 Effective 1FFP 1FFP 2–Effective 1Hemarthrosis23rFVIIa 221–21–7rFVIIa 18 – 110060Excellent 19 Effective 3PCC 1PCC 38–Excellent 1Hematomas (muscle & subcut.)8rFVIIa 41–61–12rFVIIa 54- 8066Excellent 3 Effective 1pdFVII 1pdFVII 56–Excellent 1PCC 2PCC 30–Excellent 1 n.e. 1FFP 1FFP 72–Effective 1Menorrhagia11rFVII 101–61–8rFVII 20 – 12041Excellent 5 Effective 5pdFVII 1pdFVII 135Effective 1Epistaxis & Gum bleeding12rFVIIa 511–3rFVIIa 27- 18071Excellent 4 Effective 1pdFVII 4pdFVII 21-5644Excellent 3 Effective 1FFP 3FFP 1.8-122.6Effective 3Other5rFVIIa 31-111-52rFVIIa 33-1716†33Excellent 1 Effective 2pdFVII 1pdFVII 18–Excellent 1FFP 1FFP 31–P.Effective 1*patient treated for severe hemoperitoneum; P.Effective:Partly Effective; n.e.: not evaluable ConclusionTreatment schedules and outcomes depend on the clinical setting. As for the severest bleeds (CNS and GI), on demand RT is probably not the best choice and prophylaxis should be considered as first line option especially in babies and children. Hemarthroses can be successfully treated for one day only; the number of doses used vary (from 1 to 7) as variable is the total dose of rFVIIa (from 35 to 210 μg/Kg/bw, mean 73.7, median 60) but an average intermediate dose of 60 μg/Kg/bw, possibly split in two doses, seems appropriate. The same holds for muscle and subcutaneous hematomas, always with one-day treatment schedule. RT protocols for menorrhagia varied either in terms of duration or rFVIIa total dose (1 to 6 days, total rFVIIa dosing ranging from 20 to 135 μg/Kg/bw, mean 88, median 40); treatment duration, however, did not appear to influence the outcome as one day RT showed the same efficacy as multiple days schedules. Successful RT for gum bleeding and epistaxis required treatment for one day only with doses of rFVIIa ranging from 27 to 180 μg/Kg/bw (mean 87.8, median 71) and of pdFVII ranging from 21 to 56 IU/Kg/bw (mean 41.5, median 44.5). Others bleed management were reported (hemorrhoidal, hematuria, easy bruising, peritoneal bleeding) but numbers do not allow to draw any conclusion as is the case for treatments carried out with FFP and PCCs. Disclosures:Knudsen:Novonordisk: Employment.

Activated Recombinant Factor VIIa for Intractable Extra-Cranial Hemorrhage in 55 Consecutive Patients

Abstract 1264 Background:Recombinant activated coagulation factor VII (rFVIIa) has been increasingly used in non-hemophiliac patients for unapproved indications. We undertook a 10 year nation-wide retrospective survey in order to evaluate the use of rFVIIa in Iceland in patients with intractable extra-cranial hemorrhage. Material and methods:Hospital charts of all patients that received rFVIIa between 1999–2008 at Landspitali, the single institution administering rFVIIa in Iceland, were reviewed and indications, coagulation profiles and clinical outcome were evaluated. This analysis focuses on patients treated off-label for desperate (intractable) extra-cranial hemorrhage (IH), ie only patients in who all other measures were considered to have failed to stop hemorrhage. Results:rFVIIa was used for IH in 55 patients (median age 53 yrs, range; 0–84, 51% males). This included IH in open heart surgery (n=23), non-cardiac surgery (n=7), post-partum hemorrhage (n=9), multitrauma (n=8) and miscellaneous (n=8). A single rFVIIa dose was used in 86% of cases and hemorrhage was considered effectively contained by immediate clinical response to rFVIIa in 81% of the IH cases. Survival at 30 days for all patients was 68%. Out of 55 patients with IH, six died within 24 hours of administration of rFVIIa (five assessed clinically as rFVIIa non-responders) and 11 other patients (total 17 patients, 31%) died within 30 days (six non-responders). The 24-hour mortality in rFVIIa clinical responders and non-responders was 2% and 50% respectively (p=0.0004) and the 30 day mortality was 25% and 60% respectively (p=0.05). The need for transfusion of blood products was significantly decreased (p<0.01) and also the prothrombin time (20.0 to 13.3 sec, p<0.0001). Conclusion:The majority of unselected consecutive patients receiving rFVIIa as last resort treatment for IH were considered to have favorable immediate clinical response as well as reduced transfusion requirements and normalisation of coagulation parameters. Also, patients deemed with clinical response to rFVIIa may have had lower mortality. Disclosures:Off Label Use: Activated recombinant factor VII for use in desperately bleeding patients.

A case of acquired hemophilia A with massive hemothorax

Acquired hemophilia A (AHA) is an uncommon but potentially life-threatening hemorrhagic disorder caused by the development of an inhibitor against coagulation factor VIII (FVIII). AHA is very rare, affecting approximately 1 in 1million individuals. However, the incidence may actually be higher, because diagnosis is difficult and the disease can be overlooked. We report a case of an 80-year-old man who presented with sudden onset of severe hemothorax. The patient was diagnosed with presumed AHA based on acute onset of bleeding symptoms and unexplained isolated prolonged activated partial thromboplastin time. Diagnosis was definitely established by demonstrating a decrease in FVIII activity, presence of FVIII inhibitor activity, and normal von Willebrand factor. The patient was successfully treated with recombinant activated coagulation factor VII and transcatheter artery embolization of the intercostal arteries.

Recombinant Activated Coagulation Factor VII and Prothrombin Complex Concentrates Are Equally Effective in Reducing Hematoma Volume in Experimental Warfarin-Associated Intracerebral Hemorrhage

Based on an experimental model of warfarin-associated intracerebral hemorrhage, we investigated whether the rapid reversal of anticoagulation using prothrombin complex concentrates (PCC) or recombinant activated coagulation factor VII (rFVIIa) reduces hematoma volume. Mice were orally pretreated with warfarin (2 mg/kg). Intracerebral hemorrhage was induced by collagenase injection into the right striatum. Forty-five minutes later, PCC (100 IE/kg), rFVIIa (1 mg/kg), or an equal volume of saline was administered intravenously. Hematoma volume after 24 hours was quantified using a photometric hemoglobin assay. International normalized ratio was 4.3±0.4 in saline-treated mice, 0.9±0.1 in rFVIIa mice, and 1.4±0.2 in PCC mice. Intracerebral hemorrhage volume was 29.0±19.7 μL in the saline group (n=7), 8.6±4.3 μL in the rFVIIa group (n=6), and 6.1±1.8 μL in the PCC group (n=7; analysis of variance between-group differences P=0.004; post hoc rFVIIa versus saline P=0.021; PCC versus saline P=0.007). No significant difference was found between PCC- and rFVIIa-treated animals. Our results suggest that PCC and rFVIIa are equally effective in restoring coagulation and preventing excessive hematoma growth in acute warfarin-associated intracerebral hemorrhage.

Changes in the levels of factor VIII and von Willebrand factor in the puerperium

To determine changes in Factor VIII (FVIII) and von Willebrand Factor (VWF) in the first 3 days of the puerperium. A prospective study assessing FVIII clotting activity, VWF activity and antigen levels in 95 women (with singleton uncomplicated pregnancies) during labour and on days 1, 2 and 3 of the puerperium. There were no significant differences in FVIII, VWF:Ag and VWF:CB on days 1 and 2 of the puerperium compared with levels during labour. There was a significant decrease in VWF:Ag (P = 0.009) and VWF:CB (P = 0.04) on day 3. Age, ethnicity, duration of labour and mode of delivery did not have any significant effect on the changes in FVIII and VWF levels. The pregnancy induced increase in FVIII and VWF is maintained in the first 48 h after delivery. VWF levels start to decline on day 3 postdelivery.

Relationships of plasma factor VIIa-antithrombin complexes to manifest and future cardiovascular disease

BackgroundLow levels of free activated coagulation factor VII (VIIa) are normally present in plasma to prime the coagulation of blood in normal hemostasis and during thrombus formation. VIIa also circulates in inactive form, in complex with antithrombin (VIIaAT) formed when VIIa is bound to tissue factor (TF). This study evaluated VIIaAT in relation to cardiovascular disease (CVD). MethodsWe determined the plasma VIIaAT concentration in samples from the Stockholm Coronary Atherosclerosis Risk Factor (SCARF) study, a population-based case-control study of myocardial infarction (MI) and in samples from the Stockholm study of 60-years-old individuals, a prospective study of CVD. VIIaAT was measured with a sandwich ELISA that captures the complex between a monoclonal antibody to VIIa and a polyclonal antibody to AT. ResultsIn the SCARF study (200 post-MI cases, 340 controls), VIIaAT was statistically significantly associated with patient status [odds ratio (95% confidence interval (CI)] 1.51 (1.09-2.08), p=0.0126). The case-control differences were however small, with VIIaAT values that largely overlap between the two groups. When a nested case-control design (211 incident CVD cases and 633 matched controls) was applied on 5- to 7-year follow-up results of the Stockholm prospective study of 60-year-olds, plasma VIIaAT concentration was not associated with incident CVD (odds ratio (95% CI) 1.001 (0.997-1.005), p=0.5447). ConclusionsPlasma VIIaAT concentration had no predictive value for future CVD in our study population. Slightly increased plasma VIIaAT concentrations observed after MI may reflect processes that occur in connection with the acute event when TF and VIIa availability is increased.

Prophylactic Activated Recombinant Factor VII in Liver Resection and Liver Transplantation: Systematic Review and Meta-Analysis

Background and AimIntraoperative blood loss is a frequent complication of hepatic resection and orthotopic liver transplantation. Recombinant activated coagulation factor VII (rFVIIa) is a coagulation protein that induces hemostasis by directly activating factor X. There is no clear information about the prophylactic value of rFVIIa in hepatobiliary surgery, specifically in liver resection and orthotopic liver transplantation. The aim of this study was to assess the effect of rFVIIa prophylaxis to prevent mortality and bleeding resulting from hepatobiliary surgery.MethodsRelevant randomized trials were identified by searching The Cochrane Central Register of Controlled Trials in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index. Randomized clinical trials comparing different rFVIIa prophylactic schemas against placebo or no intervention to prevent bleeding in hepatobiliary surgery were included. Adults undergoing liver resection, partial hepatectomy, or orthotopic liver transplantation were included. Dichotomous data were analyzed calculating odds ratios (ORs) and 95% confidence intervals (CIs). Continuous data were analyzed calculating mean differences (MD) and 95% CIs.ResultsFour randomized controlled trials were included. There were no significant differences between rFVIIa and placebo for mortality (OR 0.96; 95% CI 0.35–2.62), red blood cell units (MD 0.32; 95% CI −0.08–0.72) or adverse events (OR 1.55; 95% CI 0.97–2.49).ConclusionsThe available information is limited, precluding the ability to draw conclusions regarding bleeding prophylaxis in hepatobiliary surgery using rFVIIa. Although an apparent lack of effect was observed in all outcomes studied, further research is needed.

Mutation in the factor VII hepatocyte nuclear factor 4α-binding site contributes to factor VII deficiency

Severe coagulant factor VII (FVII) deficiency in postpubertal dizygotic twin males results from two point mutations in the FVII gene, a promoter region T→C transition at -60 and a His-to-Arg substitution at amino acid 348; both mutations prevent persistence of plasma functional FVII. This report documents longitudinal laboratory measurements from infancy to adulthood of FVII coagulant activity (FVII:C) in the twin FVII-deficient patients; it also details specific biochemical analyses of the -60 T→C mutation. The results revealed FVII:C levels of less than 1% in infancy that remain severely decreased through puberty and into adulthood. In-vitro analyses utilizing hepatocyte nuclear factor 4α (HNF4α) co-transfection and a chromatin immunoprecipitation assay indicate that the -60 T→C mutation severely diminishes functional interaction between the FVII promoter and transcription factor HNF4α. The importance of interaction between the FVII gene and HNF4α in normal FVII expression provides an in-vivo illustration of the regulated expression of an autosomal gene encoding a coagulation protein. The constancy of FVII:C and peripubertal patient symptomatology reported here illustrates androgen-independent expression in contrast to expression with an analogous mutation in the promoter region of the gene encoding coagulation FIX.

Haemostatic effects of simvastatin in subjects with impaired glucose tolerance

Very little is known about extra-lipid effects of statins in prediabetic subjects. Our study has assessed the effect of simvastatin on coagulation and fibrinolysis in patients with impaired glucose tolerance (IGT), comparing this effect with that exhibited by simvastatin in isolated hypercholesterolaemia. Lipid profile, fasting and 2-h post-glucose challenge plasma glucose levels, the homeostatic model assessment (HOMA) ratio, glycated haemoglobin, the prothrombin and partial thromboplastin time, plasma fibrinogen, plasminogen activator inhibitor-1 (PAI-1), von Willebrand factor (vWF), factor X levels and factor VII coagulant activity were assessed at baseline, and after 30 and 90 days of simvastatin treatment (20 mg daily) in 28 patients with IGT and 28 subjects with primary isolated hypercholesterolaemia. The control group included 26 age-, sex- and weight-matched dyslipidaemia-free individuals with normal glucose tolerance. The experiments comply with the current law of Poland. Compared to the control subjects, hypercholesterolaemic and IGT patients exhibited increased baseline plasma levels of fibrinogen, PAI-1 and vWF, and increased factor VII activity, with no difference between the two groups of patients. All these haemostatic abnormalities were alleviated or normalized after simvastatin treatment, which was accompanied by a prolongation of the prothrombin and partial thromboplastin time. In both treatment groups simvastatin reduced total and low-density lipoprotein (LDL)-cholesterol, oxidized LDL and apoprotein B but did not affect glucose metabolism marker levels. Our study shows that haemostasis is disturbed to a similar degree in IGT and isolated hypercholesterolaemia. Simvastatin exhibits a multidirectional, lipid-independent favourable action on coagulation and fibrinolysis in IGT patients, which may play a role in the prevention of initiation and progression of atherosclerosis in this prediabetic state.

Redistribution and Hemostatic Action of Recombinant Activated Factor VII Associated with Platelets

Clinical evidence accumulated from hemophilic patients during prophylaxis with recombinant activated factor VII (rFVIIa) suggests that the duration of the hemostatic action of rFVIIa exceeds its predicted plasma half-life. Mechanisms involved in this outcome have not been elucidated. We have investigated in vitro the redistribution of rFVIIa in platelets from healthy donors, patients with FVII deficiency, and one patient with Bernard-Soulier syndrome. Platelet-rich plasma was exposed to rFVIIa (3 to 60 μg/mL). Flow cytometry, immunocytochemistry, and coagulation tests were applied to detect and quantify rFVIIa. The hemostatic effect of rFVIIa associated to platelets was evaluated using perfusion models. Our studies revealed a dose-dependent association of rFVIIa to the platelet cytoplasm with redistribution into the open canalicular system, and α granules. Mechanisms implicated in the internalization are multiple, involve GPIb and GPIV, and require phospholipids and cytoskeletal assembly. After platelet activation with thrombin, platelets exposed rFVIIa on their membrane. Perfusion studies revealed that the presence of 30% of platelets containing FVIIa improved platelet aggregate formation and enhanced fibrin generation (P < 0.01 versus control). Our results indicate that, at therapeutic concentrations, rFVIIa can be internalized into platelets, where it is protected from physiological clearance mechanisms and can still promote hemostatic activity. Redistribution of rFVIIa into platelets may explain the prolonged prophylactic effectiveness of rFVIIa in hemophilia.

Replacing dairy fat with rapeseed oil causes rapid improvement of hyperlipidaemia: a randomized controlled study

Rapeseed oil (RO), also known as canola oil, principally contains the unsaturated fatty acids 18:1n-9, 18:2n-6 and 18:3n-3 and may promote cardiometabolic health. To investigate the effects on lipoprotein profile, factors of coagulation and insulin sensitivity of replacing a diet rich in saturated fat from dairy foods (DF diet) with a diet including RO-based fat (RO diet). During a 2×3-week randomized, controlled, cross-over trial, 20 free-living hyperlipidaemic subjects were provided with isocaloric test diets that differed in fat composition alone. Blood lipoprotein profile, coagulation and fibrinolytic factors and insulin sensitivity (euglycaemic clamp) were determined before and after the dietary intervention. All subjects completed the study, and compliance was high according to changes in serum fatty acids. The RO diet, but not the DF diet, reduced the levels of serum cholesterol (-17%), triglycerides (-20%) and low-density lipoprotein cholesterol (-17%), cholesterol/high-density lipoprotein (HDL) cholesterol ratio (-21%), apolipoprotein (apo) B/apo A-I ratio (-4%) and factor VII coagulant activity (FVIIc) (-5%) from baseline. These changes were significantly different between the diets (P=0.05 to P<0.0001), except for FVIIc (P=0.1). The RO diet, but not the DF diet, modestly increased serum lipoprotein(a) (+6%) and tended to increase the glucose disappearance rate (K-value, +33%). HDL cholesterol, insulin sensitivity, fibrinogen and tissue plasminogen activator inhibitor-1 levels did not change from baseline or differ between the two diets. In a diet moderately high in total fat, replacing dairy fat with RO causes a rapid and clinically relevant improvement in serum lipoprotein profile including lowering of triglycerides in hyperlipidaemic individuals.

Off-label use of recombinant activated coagulation factor VII for bleeding may raise the risk of arterial thrombosis

Recombinant activated coagulation factor VII (rFVIIa), structurally nearly identical to human plasma-derived coagulation factor VIIa, is thought to promote haemostasis by activating coagulation cascade, and converting prothrombin to thrombin. Initially, recombinant factor VIIa was approved for the treatment of bleeding in patients with haemophilia A or B who have inhibiting antibodies to coagulation factor VIII or IX. Later, indications were broadened to include the treatment of bleeding events, and the prevention of bleeding episodes related to surgical or invasive procedures, in patients with congenital or acquired haemophilia, factor VII deficiency, or Glanzmann’s thrombasthenia. However, in recent years, rFVIIa has been used, on an off-label basis, to act as a pro-haemostatic agent in patients with a pre-existent normal coagulation system who experienced massive or uncontrolled bleeding. In the past decade, the use of rFVIIa for the approved haemophilia indications remained stable over time, whereas the off-label prescriptions increased: according to the recent surveys, more than 90% of rFVIIa prescriptions are for off-label indications [1, 2]. Given the physiology of activated factor VII, a potential adverse event of concern is the risk of thromboembolic complications. Summary

Hemostatic effects of bezafibrate and ω-3 fatty acids in isolated hypertriglyceridemic patients

This study aimed to compare the effects of ω-3 fatty acids and fibrate treatment on plasma levels and activities of hemostatic risk factors on glucose and lipid metabolism in subjects with isolated hypertriglyceridemia. Seventy-three subjects with elevated triglyceride levels were allocated into one of the following treatment options: bezafibrate (200mg twice daily), ω-3 fatty acids (1g twice daily) or placebo. Plasma lipids, glucose homeostasis markers (fasting and 2-h post-glucose load plasma glucose levels and HOMA), as well as plasma levels/activities of fibrinogen, factor VII and PAI-1 were determined at baseline, on the day of randomization, and after 4 and 12 weeks of the treatment. Not only did bezafibrate improve plasma lipids, but it also increased glucose sensitivity and tended to reduce post-glucose loads of plasma glucose. Except for the reduction in plasma triglycerides, ω-3 fatty acids produced no effect on the lipid profile and insulin sensitivity. Both treatment options reduced, to similar extents, plasma levels of fibrinogen and PAI-1 and factor VII coagulant activity. Our study indicates that, although fibrates exhibit more-pronounced metabolic effects than do ω-3 fatty acids, both these treatment options are equipotent in producing a complex beneficial effect on hemostasis in isolated hypertriglyceridemic subjects.

The pharmacokinetic diversity of two von Willebrand factor (VWF)/ factor VIII (FVIII) concentrates in subjects with congenital von Willebrand disease

The pharmacokinetic (PK) profiles of von Willebrand factor (VWF) /factor VIII (FVIII) concentrates are important for treatment efficacy and safety of von Willebrand disease (VWD) patients. This prospective, head-to-head, randomised crossover study compared the PK profile of a new, high purity, human plasma-derived (pd)VWF/FVIII concentrate, Wilate, with the PK profile of an intermediate purity (pd)VWF/FVIII concentrate, Humate-P, in VWD patients. Subjects with inherited VWD were randomised to a single intravenous dose (40 IU/kg VWF ristocetin cofactor activity [VWF:RCo]) of Wilate or Humate-P in Period 1, and switched to the other study drug in Period 2. Each period was preceded by a washout time of ≥ 7 days. Coagulation factor parameters were analysed at multiple time-points. Of 22 randomised subjects, 20 had evaluable PK profiles, which indicated comparability for VWF antigen and VWF:RCo between Wilate and Humate-P. The reported VWF:RCo average and terminal t1/2 of 10.4 and 15.8 hours (h), respectively, for Wilate and 9.3 h and 12.8 h for Humate-P, were not statistically different. Also, the mean VWF:RCo in vivo recoveries (Wilate 1.89, Humate-P 1.99 IU/dl per IU/kg) were similar between the two replacement therapies. Wilate showed parallel decay curves for VWF:RCo and FVIII clotting activity (FVIII:C) over time, while FVIII:C of Humate-P displayed a plateau between 0 and 12-24 h. This study demonstrated bioequivalent PK properties for VWF between Wilate and Humate-P. The PK profile of Wilate, combined with the 1:1 VWF/FVIII ratio, theoretically should facilitate dosing and laboratory monitoring of VWF replacement to prevent bleeding in individuals with VWD.