Fifth Åland Island conference on von Willebrand disease.

The fifth Åland Island meeting on von Willebrand disease (VWD) was held on the Åland Islands, Finland, from 22 to 24 September 2016-90 years after the first case of VWD was diagnosed in a patient from the Åland Islands in 1926. This meeting brought together experts in the field of VWD to share knowledge and expertise on current trends and challenges in VWD. Topics included the storage and release of von Willebrand factor (VWF), epidemiology and diagnostics in VWD, treatment of VWD, angiogenesis and VWF inhibitors.

Efficacy and safety of Nuwiq® (human-cl rhFVIII) in patients with severe haemophilia A undergoing surgical procedures.

INTRODUCTION: Haemophilia A patients are at a high risk of excess bleeding during surgeries. The aim of haemostatic therapy during the perioperative period is to normalize FVIII level perioperatively and postoperatively to maintain normal haemostasis until wound healing is complete. AIMS/METHODS: To examine the efficacy of Nuwiq® (simoctocog alfa, human-cl rhFVIII), a 4th generation recombinant FVIII produced in a human cell line, for surgical prophylaxis in patients with severe haemophilia A. This analysis assessed the efficacy of Nuwiq® during surgical procedures and in the postoperative period in seven clinical studies of previously treated patients (PTPs) with severe haemophilia A. RESULTS: Thirty-six patients, aged 3-55 years, received surgical prophylaxis with Nuwiq® for 60 surgeries (28 major and 32 minor). Efficacy was evaluated for 52 surgeries (25 major and 27 minor). The success rate of Nuwiq® treatment was 98.1% (51 of 52 evaluated surgeries); haemostatic efficacy was assessed as "excellent" or "good" in all but one major surgery (assessed as "moderate"). The number of infusions ranged from 1 to 19 for minor surgeries and from 3 to 76 for major surgeries. The median (range) daily doses were 42.0 (28.2-100.9) IU kg-1 for minor surgeries and 69.3 (43.3-135.6) IU kg-1 for major surgeries. There were no serious treatment-related adverse events, and none of the patients developed FVIII inhibitors. CONCLUSIONS: The results of this pooled analysis show that Nuwiq® was efficacious in maintaining haemostasis during and after major and minor surgical procedures in PTPs with severe haemophilia A.

Novel, human cell line-derived recombinant factor VIII (human-cl rhFVIII; Nuwiq® ) in adults with severe haemophilia A: efficacy and safety.

INTRODUCTION: Nuwiq® [human cell line-derived recombinant factor VIII (human-cl rhFVIII)] is a new generation rFVIII protein, without chemical modification or fusion to any other protein, produced in a human cell line. AIM/METHODS: This prospective, open-label, multinational phase III study assessed the efficacy and safety of human-cl rhFVIII in 32 adult previously treated patients (PTPs) with severe haemophilia A during standard prophylaxis for ≥6 months and ≥50 exposure days. Efficacy in treating bleeds and during surgical prophylaxis was also assessed. RESULTS: Prophylactic efficacy, based on mean monthly bleeding rate, was rated as 'excellent' or 'good' in 97% of patients for all bleeds and in 100% of patients for spontaneous bleeds. Mean (SD) annualized bleeding rate was 2.28 (3.73) [median = 0.9] for all bleeds, 1.16 (2.57) [median = 0] for spontaneous bleeds and 1.00 (1.79) [median = 0] for traumatic bleeds. There were no bleeds in 50% of patients and there were no major, life-threatening bleeds. Efficacy was 'excellent' or 'good' in treating 28 (100%) of 28 bleeds. Overall efficacy was rated as 'excellent' during four surgical procedures (three major, one minor) and 'moderate' during one major surgery. Incremental in vivo recovery (IVR) data were comparable with the one-stage and chromogenic assays. IVR was >2.0% per IU kg-1 for all measurements and stable over 6 months. No patients developed FVIII inhibitors and there were no treatment-related serious or severe adverse events. CONCLUSION: These results in adult PTPs indicate that human-cl rhFVIII is effective for the prevention and treatment of bleeds in adults with severe haemophilia A.

von Willebrand's disease: a report from a meeting in the Åland islands.

von Willebrand's disease (VWD) is probably the most common bleeding disorder, with some studies indicating that up to 1% of the population may have the condition. Over recent years interest in VWD has fallen compared to that of haemophilia, partly the result of focus on blood-borne diseases such as HIV and hepatitis. Now the time has come to revisit VWD, and in view of this some 60 international physicians with clinical and scientific interest in VWD met over 4 days in 2010 in the Åland islands to discuss state-of-the-art issues in the disease. The Åland islands are where Erik von Willebrand had first observed a bleeding disorder in a number of members of a family from Föglö, and 2010 was also the 140th anniversary of his birth. This report summarizes the main papers presented at the symposium; topics ranged from genetics and biochemistry through to classification of VWD, pharmacokinetics and laboratory assays used in the diagnosis of the disease, inhibitors, treatment guidelines in different age groups including the elderly who often have comorbid conditions that present challenges, and prophylaxis. Other topics included managing surgeries in patients with VWD and the role of FVIII in VWF replacement, a controversial subject.

Acquired type 2A von Willebrand syndrome caused by aortic valve disease corrects during valve surgery.

BACKGROUND: Aortic valve (AV) defects can destroy high molecular weight multimers (HMWM) of von Willebrand factor (VWF), leading to acquired von Willebrand syndrome (aVWS) type IIA. This syndrome is considered a cause for increased perioperative bleeding in AV surgery. If diagnosed before operation, administration of VWF/FVIII concentrates is recommended. However, there is currently no evidence that the VWF HMWM defect persists during surgery long enough to require haemostatic therapy. We hypothesized that the preoperative VWF HMWM defect corrects already during cardiopulmonary bypass (CPB) before any haemostatic therapy. METHODS: This prospective observational study enrolled 17 patients undergoing AV surgery, either isolated or associated with mitral valve or aorta surgery, and also 10 patients undergoing coronary artery bypass surgery (CABG) for comparison. VWF HMWM, VWF antigen (VWF:Ag) concentration, and collagen-binding capacity (VWF:CB) were measured before operation, directly after weaning from CPB, and on the first postoperative day. RESULTS: In 12 of the 17 subjects undergoing AV surgery (71%), VWF HMWM were abnormally absent before operation. At the end of CPB, VWF HMWM were normal in 15 of AV subjects (88%), and was normal in 16 subjects on the first postoperative day. VWF:Ag and VWF:CB were within or above the normal range at all three times. Two out of 10 subjects undergoing CABG (20%) had preoperative deficits of VWF HMWM that normalized after operation. CONCLUSIONS: Preoperative VWF HMWM defects corrected at the end of CPB in the absence of haemostatic therapy in most patients undergoing AV surgery. Diffuse bleeding occurring after CPB is unlikely to be related to persisting type 2A von Willebrand syndrome; other causes of coagulopathy should be suspected. Administration of VWF/FVIII concentrates appears unnecessary in this setting.

Non-genetic risk factors and the development of inhibitors in haemophilia: a comprehensive review and consensus report.

SUMMARY: The development of inhibitors to the infused factor in patients with haemophilia is a serious clinical problem. Recent evidence suggests that alongside the strong genetic contribution to inhibitor formation, there are a number of non-genetic factors--perceived by the immune system as danger signals--which promote formation of inhibitors. This study provides a comprehensive review of clinical studies relating to these factors and also presents a survey of opinion concerning their importance and clinical influence, conducted among the members of the European Haemophilia Treatment Standardisation Board (EHTSB). Taken together, this information highlights the lack of robust data concerning the influence of several non-genetic risk factors on inhibitor development, and an urgent need for prospective, well-conducted studies that adhere to recommendations made by the European Medicines Agency (EMEA) for studying inhibitors. Based on current literature, the EHTSB formulated consensus recommendations. It is desirable to minimize intensive treatment wherever possible, given the clinical situation. Prophylaxis should be offered to all children, although we still need to determine optimal dosing with respect to inhibitor development, and age for starting treatment. Vaccinations should be given subcutaneously and concomitant factor concentrate infusions avoided. According to the board, there is no evidence in the literature supporting suggestions that the type of concentrate influences inhibitor risk; but all patients should be monitored during their first exposures. Furthermore, there is no evidence to support an association between pregnancy-related issues, breast feeding and treatment-related factors (e.g. route of administration, or use of blood components) and inhibitor development.

Experiences with recombinant FVIIa in the emergency treatment of patients with autoimmune thrombocytopenia: a review of the literature.

Patients with severe and refractory autoimmune thrombocytopenia (ITP) have significant morbidity and mortality rates. Currently, high-dose methylprednisolone and/or high-dose IVIgG are recommended for the emergency treatment of such patients with uncontrolled bleeding. However, some patients do not immediately respond to these therapeutic regimes and may require additional treatment. Recombinant activated FVIIa (rFVIIa) is a prothrombotic agent that appears to be useful in the treatment of patients with life-threatening bleeding. It has also been used in the treatment of several patients with thrombocytopenia. We administered rFVIIa into a patient with refractory ITP and performed a systemic review of all published reports to assess the available evidence on the efficacy and safety of this drug in patients with ITP. The results indicate that rFVIIa may help in the emergency treatment of patients with ITP who do not respond to other therapies.

Current use of by-passing agents in Europe in the management of acute bleeds in patients with haemophilia and inhibitors.

The ultimate goal of treatment for patients with inhibitory antibodies should be to permanently eradicate the inhibitor by immune tolerance induction therapy (ITI). However, ITI procedures fail in a substantial number of patients and in many countries ITI is not even offered owing to its high cost. How patients with inhibitors are managed in different European countries is evaluated with a special focus on the use of by-passing agents, i.e. recombinant FVIIa (rFVIIa) and activated prothrombin complex concentrates (aPCC), as well as the type of monitoring performed. Investigators from 22 large haemophilia centres participating within the network of the European Haemophilia Therapy Standardisation Board (EHTSB) were asked to complete a questionnaire. rFVIIa was routinely used in all centres for both children and adults at dosages ranging from 90 to 250 mug kg(-1) at an interval of 2-4 h. aPCC was used in 85% of the centres in adults and in 25% of the centres in children with haemophilia A at dosages of 50-100 IU kg(-1) every 6-12 h. The corresponding figures for children and adults with haemophilia B were 40% and 15% of the centres, respectively. Higher dosages of both agents were considered in the case of life-threatening bleeds. General recommendations were developed, based on the information provided by the survey. The results clearly indicate the need for well-designed comparative studies to optimize the use of by-passing agents.

[Possibilities and limitations of thrombelastometry/-graphy]. / Diagnostische Möglichkeiten und Grenzen der Thrombelastometrie/-graphie.

Thrombelastometry/-graphy provides information about clot strength and stability. Modified thrombelastometry/-graphy improved standardisation and diagnostic information using this system. Heparinase modified thrombelastometry/-graphy allows estimation of heparin. The introduction of FIBTEM on the ROTEM first allows a clear estimation of the plasmatic and the platelet component of clot strength, which may be of interest in managing haemostasis in perioperative setting. In this context the meaning of fibrinogen should be evaluated. As our clinical data show there is no predictive value of elevated D-dimers to hyperfibrinolysis in perioperative setting. However, thrombelastometry/-graphy do not deteckt disturbances in primary haemostasis such as von Willebrand Syndrom. The effect of acetylsalicylacid and clopidogrel do not have any influence on thrombelastometry/-graphy, as well. GPIIb/IIIa-Antagonists such as ReoPro may reduce clot strength at high dosis. A similar effect may be expected in severe M. Glanzmann. The correlation between coagulation time in thrombelastometry/-graphy (CT/r-value) to conventional coagulation may be low because of different activators used. The introduction of rotationthrombelastometry (ROTEM) provides a stable system suitable for bedside-monitoring.

Current European practice in immune tolerance induction therapy in patients with haemophilia and inhibitors.

The management of patients with inhibitors is an important challenge in haemophilia care. The lack of randomized controlled trials means that clinical decisions are generally based on subjective opinions, and purchasers' attention is likely to focus on the costs of treatment. In order to assess the current management of inhibitor patients and use of immune tolerance induction therapy (ITI) in Europe, we performed a survey within a European network of 21 comprehensive care centres from 14 countries (the European Haemophilia Therapy Standardisation Board). The survey identified a total of 381 patients with inhibitors attending the centres, 211 (55.4%) of whom had never been exposed to ITI. Between 1998 and 2003, the centres performed 233 procedures and 114 (48.9%) were successful. The survey demonstrated that dosing, which is the time to start and stop the ITI, the type of concentrate to use and the definition of success varied among the centres. Well-designed trials are warranted to guide decision-making, but in the absence of these studies we have developed consensus guidance for the management of inhibitor patients based on current clinical practice, as identified by the survey, and review of the literature.

Managing acute bleeds in the patient with haemophilia and inhibitors: options, efficacy and safety.

The options available for treating the patient with haemophilia and inhibitors undergoing surgery or with other acute bleeds include high-dose factor VIII (FVIII) (human or porcine), prothrombin complex concentrates (PCCs), activated PCCs (aPCCs), recombinant activated factor VII (rFVIIa), and factor replacement combined with immunoadsorption or immunosuppression. Human FVIII is effective in patients with low-titre inhibitors. Porcine FVIII is currently not available, and PCCs and aPCCs, although effective, have been associated with a high incidence of adverse events. Immunoadsorption and immunosuppression offer excellent long-term solutions, but the duration of these techniques makes them less attractive for use in acute settings. Recombinant FVIIa has demonstrated excellent efficacy and safety, even in patients refractory to other therapies.

Inhibitor development in patients with hemophilia A after continuous infusion of FVIII concentrates.

Continuous infusion (CI) of coagulation factor concentrates has been used since the early 1990s. Recent reports of the occurrence of an inhibitor after CI have raised concerns about this method of treatment. We conducted a retrospective study to investigate the development of inhibitors after CI of Factor VIII concentrates in Germany. So far, 13 hemophilia centers have been contacted, and data have been collected by a questionnaire. Of the 13 centers, CI had never been performed in three, no inhibitors had been detected in five, and inhibitor development after CI was recorded in 10 patients in the remaining five centers. Of these 10 patients (ages 7 months to 57 years), five were suffering from severe, one from moderate, and four from mild hemophilia. Indications for treatment were major bleeds and surgical procedures. Plasma-derived (6 cases) and recombinant (4 cases) factor concentrates were given in various infusion sets. Data concerning amount infused (4300 to > 100,000 IU), number of days of exposure to factor concentrates (1 to > 100), and inhibitor characteristics (alloantibodies, 3 LR, 7 HR) were collected. Regarding hemophilia genotype, we found missense mutations in four patients, intron-22 inversions in two, and one small deletion in one; the genotype in three was unknown. In conclusion, only 3 out of 10 patients who developed an inhibitor after CI showed the typical risk profile for inhibitor formation, which is severe hemophilia A with a severe gene defect and less than 50 days of exposure to coagulation factor concentrates. Especially striking was the finding that 50% of the patients who developed inhibitors had mild to moderate hemophilia A. Our data point to the existence of a so-far unknown factor, related to CI, that might lead to inhibitor formation.

Prophylactic and therapeutic recombinant factor VIIa administration to patients with Glanzmann's thrombasthenia: results of an international survey.

BACKGROUND: Antibodies to glycoprotein (GP) IIb-IIIa and/or HLA may render platelet transfusions ineffective to stop bleeding or to cover surgery in patients with Glanzmann's thrombasthenia (GT). Anecdotal reports suggest recombinant factor (rF)VIIa might be a therapeutic alternative in these situations. OBJECTIVES: An international survey was conducted to evaluate further the efficacy and safety of rFVIIa in GT patients. PATIENTS: We analyzed the use of rFVIIa during 34 surgical/invasive procedures and 108 bleeding episodes in 59 GT patients including 29 with current or previous antiplatelet antibodies, and 23 with a history of refractoriness to platelet transfusion. RESULTS: rFVIIa was effective in 29 of the 31 evaluable procedures, and in 77 of the 103 evaluable bleeding episodes of which eight had a recurrence. A significantly higher success rate was observed in severe bleeding episodes when an arbitrarily defined 'optimal regimen' derived from the Canadian pilot study results (> or = 80 micro g kg(-1) rFVIIa/injection, dosing interval < or = 2.5 h, three or more doses before failure declaration) was used compared with other regimens (77%; 24/31 vs. 48%, 19/40; chi(2), P = 0.010). Patients given maintenance doses had significantly fewer recurrences within 48 h of bleed cessation compared with those not given any (Fisher's exact test, P = 0.022). One thromboembolic event and one blood clot in the ureter occurring in surgical patients following prolonged continuous infusion of high-dose rFVIIa and antifibrinolytic drug use have been previously reported. CONCLUSION: rFVIIa seems a potential alternative to platelet transfusion in GT patients, particularly in those with antiplatelet antibodies and/or platelet refractoriness.

Recombinant factor VIII expression in hematopoietic cells following lentiviral transduction.

Autologous transplantation of gene-modified hematopoietic stem cells may provide a therapeutic strategy for several monogeneic disorders. In previous studies, retroviral gene transfer of coagulation factor VIII (FVIII) into FVIII(-/-) mouse bone marrow (BM) cells did not result in detectable plasma FVIII levels. However, specific immune tolerance was achieved against neo-antigenic FVIII. Here, we used lentiviral vectors to study the ability of various hematopoietic cell types to synthesize and secrete recombinant FVIII. Several myeloid, monocytic and megakaryocytic cell lines (K-562, TF-1, Monomac-1, Mutz-3, Meg-01) expressed FVIII at 2-12 mU/10(4) cells. In contrast, two lymphatic cell lines, BV-173 and Molt-4, were less-efficiently transduced and did not express detectable FVIII. Similarly, peripheral blood-derived primary monocytes were transduced efficiently and expressed up to 20 mU/10(4) cells, whereas primary lymphocytes did not express FVIII. Although human and canine CD34(+) cells were transduced efficiently, the cells expressed very low levels of FVIII (up to 0.8 mU/10(4) cells). Following xenotransplantation of transduced CD34(+) into NOD/SCID mice, ELISA failed to detect FVIII in the plasma of engrafted mice. However, NOD/SCID repopulating cell (SRC)-derived human monocytes isolated from BM of these mice secreted functional recombinant FVIII after culture ex vivo. Again, SRC-derived human lymphocytes did not secrete FVIII. Therefore, certain hematopoietic cell types are able to synthesize and secrete functional recombinant FVIII. Our results show for the first time that transplantation of transduced CD34(+) progenitors may give rise to differentiated hematopoietic cells secreting a nonhematopoietic recombinant protein.

The ex-vivo-shunt-model: novel approach for assessing the thrombogenicity of vascular implants.

OBJECTIVE: Disadvantages associated with commercially available vascular implants necessitate alternative strategies to develop new vascular prostheses. Although many tissue characterizing strategies have been defined, no valid test for thrombogenicity exists. Here we introduce a novel concept for thrombogenicity testing of vascular implants METHODS: Silastic tubes were implanted into the carotid arteries of 12 sheep. After placing these shunts, tc99m-labeled platelets were administered and test-vessels were put in between the shunts. Native autologous (n=6), as well as native/acellularized allogeneic (n=6/n=6), and xenogeneic (n=6/n=6) carotid arteries and allogeneic (n=6/n=6) and xenogeneic (n=6/n=6) carotid arteries reseeded with allogeneic endothelial-cells, fibroblasts and myocytes were evaluated. Number and time course of intra-operatively deposited platelets were evaluated with a Geiger-counter; certain areas of platelet deposition located, envisioned and characterized by a gamma-camera and scanning electron-microscopy afterwards. RESULTS: Counter results revealed no significant different platelet depositions when comparing silastic tubes with either autologous or allogeneic native carotid arteries. However, starting 5 minutes after placement, acellularized/reseeded allogeneic (p=0.001/p=0.00004), and xenogeneic (p=0.0001/p=0.01) carotid arteries showed significantly more platelet depositions than native autologous carotides. Moreover, it was possible to show that almost no platelets adhere to native vessels or silastic tubes, thus proving the test method itself. CONCLUSION: The Ex-Vivo-Shunt-Model is a valid method to measure and envision the intrinsic thrombogenicity of vascular implants.

Use of recombinant factor VIIa (NovoSeven) in patients with Glanzmann thrombasthenia.

Recombinant factor VIIa (rFVIIa; NovoSeven, Novo Nordisk, Bagsvaerd, Denmark) appears effective and relatively safe for the treatment of bleeding and for surgical prophylaxis in patients with Glanzmann thrombasthenia as reported to the International Registry on rFVIIa and Congenital Platelet Disorders. One of the shortcomings of the Registry data is the heterogeneity of treatment protocol, including dosage, number of doses used, duration of treatment before declaration of failure, and mode of rFVIIa administration (bolus v continuous infusion). The data are not yet sufficient to define optimal regimens for various indications such as the type of bleeding or the type of procedures. The place of this drug compared to platelet transfusion in the overall management of patients with Glanzmann thrombasthenia will need to be determined in relationship to a number of challenges and unresolved issues in the clinical care of these patients. These issues include: how to improve local measures for patients with mucosal bleeds, optimal management of young women during menarche, optimal platelet transfusion regimens for various indications, the relationship between antiplatelet antibodies detected by monoclonal antibody-specific immobilization of platelet antigens (MAIPA) and effectiveness of platelet transfusion, whether there are other biological tests that may correlate with effectiveness of platelet transfusion, and management of pregnancy and delivery regarding antiplatelet immunization.

Autoimmune hepatitis associated with coagulation disorders and immunethyreopathy.

We present the case of a 42-year-old female patient with the diagnoses of autoimmune hepatitis type I and autoimmune thyroiditis. Furthermore this patient had an unusual combination of coagulation disorders with homozygous Factor V Leiden mutation (APC resistance) and presence of antiphospholipid antibodies, leading to deep vein thromboses and miscarriages. Only few cases with the combination of autoimmune hepatitis and antiphospholipid antibodies have been described and almost all of them had become symptomatic with the antiphospholipid syndrome. As both autoimmune phenomenons furthermore share similar HLA-patterns, their coincidence is probably not as uncommon as the limited number of case reports suggests. Therefore attention in patients with autoimmune hepatitis should be focused on thrombophilia.