Surgery in rare bleeding disorders: the prospective MARACHI study

Background

Despite the wide use of bleeding scores and the reliability of clotting factor level measurement, bleeding risk stratification before surgery remains challenging in patients with rare inherited bleeding disorders.

Objectives

This multicenter observational prospective study assessed in patients with rare coagulation factor deficiency, the perioperative hemostatic management choices by hemostasis experts and the bleeding outcomes after surgery.

Methods

One hundred seventy-eight patients with low coagulation activity level (factor [F] II, FV, combined FV-FVIII, FVII, FX, or FXI <50%) underwent 207 surgical procedures. The bleeding outcome, Tosetto's bleeding score, and perioperative hemostatic protocols were collected.

Results

Among the 81 procedures performed in patients with severe factor deficiency (level ≤10%), 27 were done without factor replacement (including 6 in patients at high bleeding risk), without any bleeding event. Factor replacement therapy was used mainly for orthopedic procedures. In patients with mild deficiency, 100/126 surgical procedures were carried out without perioperative hemostatic treatment. In patients with FVII or FXI deficiency, factor replacement therapy was in function of the procedure, bleeding risk, and to a lesser extent previous bleeding history. Tranexamic acid was used in almost half of the procedures, particularly in case of surgery in tissues with high fibrinolytic activity (76.8%).

Conclusions

The current perioperative hemostatic management of patients with rare bleeding disorders appears to be adapted. Among the 207 procedures, only 6 were associated with excessive bleeding. Our findings suggest that rather than the bleeding score, factor level and surgery type are the most relevant criteria for perioperative factor replacement therapy.

Compliance with Early Long-Term Prophylaxis Guidelines for Severe Hemophilia A

OBJECTIVES

To evaluate the applicability and compliance with guidelines for early initiation of long-term prophylaxis in infants with severe hemophilia A and to identify factors associated with guideline compliance.

STUDY DESIGN

This real-world, prospective, multicenter, population-based FranceCoag study included almost all French boys with severe hemophilia A, born between 2000 and 2009 (ie, after guideline implementation).

RESULTS

We included 333 boys in the study cohort. The cumulative incidence of long-term prophylaxis use was 61.2% at 3 years of age vs 9.5% in a historical cohort of 39 boys born in 1996 (ie, before guideline implementation). The guidelines were not applicable in 23.1% of patients due to an early intracranial bleeding or inhibitor development. Long-term prophylaxis was delayed in 10.8% of patients. In the multivariate analysis, 2 variables were significantly associated with "timely long-term prophylaxis" as compared with "delayed long-term prophylaxis": hemophilia treating center location in the southern regions of France (OR 23.6, 95% CI 1.9-286.7, P = .013 vs Paris area) and older age at long-term prophylaxis indication (OR 7.2 for each additional year, 95% CI 1.2-43.2, P = .031). Long-term prophylaxis anticipation was observed in 39.0% of patients. Earlier birth year (OR 0.5, 95% CI 0.3-0.8, P = .010 for birth years 2005-2009 vs 2000-2004) and age at first factor replacement (OR 1.9 for each additional year, 95% CI 1.2-3.0, P = .005) were significantly associated with "long-term prophylaxis guideline compliance" vs "long-term prophylaxis anticipation."

CONCLUSIONS

This study suggests that long-term prophylaxis guidelines are associated with increased long-term prophylaxis use. However, early initiation of long-term prophylaxis remains a challenge.

Gastrointestinal bleeding from angiodysplasia in von Willebrand disease: Improved diagnosis and outcome prediction using videocapsule on top of conventional endoscopy

BACKGROUND

Despite a high prevalence of angiodysplasia, no specific guidelines are available for the modalities of endoscopic exploration of gastrointestinal (GI) bleeding in von Willebrand disease (VWD). Whether VWD patients could benefit from video capsule endoscopy (VCE) looking for angiodysplasia eligible to endoscopic treatment or at high risk of bleeding is unknown.

OBJECTIVES

To assess the diagnostic efficacy for angiodysplasia and the prognostic value of VCE on top of conventional endoscopy in VWD patients with GI bleeding.

PATIENTS/METHODS

A survey was sent to the 30 centers of the French-network on inherited bleeding disorders to identify VWD patients referred for endoscopic exploration of GI bleeding from January 2015 to December 2017. Data obtained included patient characteristics, VWD phenotype/genotype, GI bleeding pattern, results of endoscopic investigations, and medical management applied including endoscopic therapy. We assessed by Kaplan-Meier analysis the recurrence-free survival after the first GI bleeding event according to endoscopic categorization and, in patients with angiodysplasia, to the presence of small-bowel localizations on VCE exploration.

RESULTS

GI bleeding source localization was significantly improved when including VCE exploration (P < .01), even in patients without history of angiodysplasia (P < .05). Patients with angiodysplasia had more GI bleeding recurrences (P < .01). A lower recurrence-free survival was observed in patients with angiodysplasia (log-rank test, P = .02), and especially when lesions were located in the small bowel (log-rank test, P < .01), even after endoscopic treatment with argon plasma coagulation (log-rank test, P < .01).

CONCLUSION

VCE should be more systematically used in VWD patients with unexplained or recurrent GI bleeding looking for angiodysplasia eligible to endoscopic treatment or at high risk of relapse.

Determinants of adherence and consequences of the transition from adolescence to adulthood among young people with severe haemophilia (TRANSHEMO): study protocol for a multicentric French national observational cross-sectional study

INTRODUCTION

Severe haemophilia is a rare disease characterised by spontaneous bleeding from early childhood, which may lead to various complications, especially in joints. It is nowadays possible to avoid these complications thanks to substitutive therapies for which the issue of adherence is major. The transition from adolescence to adulthood in young people with severe haemophilia is a critical period as it is associated with a high risk of lack of adherence to healthcare, which might have serious consequences on daily activities and on quality of life.

METHODS AND ANALYSIS

We present the protocol for a cross-sectional, observational, multicentric study to assess the differences between adolescents and young adults with severe haemophilia in France through the transition process, especially on adherence to healthcare. This study is based on a mixed methods design, with two complementary and consecutive phases, comparing data from a group of adolescents (aged 14-17 years) with those from a group of young adults (aged 20-29 years). The quantitative phase focuses on the determinants (medical, organisational, sociodemographic and social and psychosocial and behavioural factors) of adherence to healthcare (considered as a marker of the success of transition). The qualitative phase explores participants' views in more depth to explain and refine the results from the quantitative phase. Eligible patients are contacted by the various Haemophilia Treatment Centres participating in the French national registry FranceCoag.

ETHICS AND DISSEMINATION

The study was approved by the French Ethics Committee and by the French National Agency for Medicines and Health Products Safety (number: 2016-A01034-47). Study findings will be disseminated to the scientific and medical community in peer-reviewed journals and presented at scientific meetings. Results will be popularised to be communicated via the French association for people with haemophilia to participants and to the general public.

TRIAL REGISTRATION NUMBER

NCT02866526; Pre-results.

Point of Care Tests VerifyNow P2Y12 and INNOVANCE PFA P2Y Compared to Light Transmittance Aggregometry After Fibrinolysis

Detection of high on-treatment platelet reactivity (HPR) by point-of-care tests has not been validated after successful fibrinolysis for ST-elevation myocardial infarction. We assessed the validity of the point-of-care VerifyNow P2Y12 (VN) and INNOVANCE PFA P2Y (PFA) tests on HPR compared to light transmittance aggregometry (LTA) in these patients. The HPR was identified in 10 (34.5%) patients, 15 (51.7%) patients, and 14 (50%) patients using LTA, VN, and PFA, respectively. Discrepancies were observed between the tests despite significant correlations between platelet reactivity measures by LTA and VN (r = 0.74; P < .0001) and LTA and PFA (r = .75; P < .0001). Compared to LTA, VN and PFA were associated with a 92% and 53% and 92% and 64% positive predictive value (PPV) and negative predictive value (NPV), respectively, in detecting HPR. When combined, VN and PFA results yielded 90% and 100% PPV and NPV values if discrepancies between the 2 tests were considered as non-HPR. The VN or PFA identify patients without HPR correctly but overestimate the proportion of HPR patients. The association of the 2 tests, in case of HPR, improves the accuracy of the detection of HPR.

A national French noninterventional study to assess the long-term safety and efficacy of reformulated nonacog alfa

BACKGROUND

Nonacog alfa, the recombinant Factor IX (F IX) used for the treatment of hemophilia B, was approved in Europe in 1998. A reformulated version was approved for European use in 2007.

STUDY DESIGN AND METHODS

This postmarketing study, as recommended by the risk management plan, was conducted to confirm the safety of reformulated nonacog alfa in a usual care setting in France. This open-label, noninterventional, prospective, longitudinal postmarketing study comprised 19 French hemophilia centers. Patients with hemophilia B receiving reformulated nonacog alfa for prophylaxis or on-demand treatment were followed up on usual care schedule.

RESULTS

A total of 58 subjects were enrolled, of whom 29 (50%) were less than 18 years of age. Hemophilia was severe (baseline F IX activity < 1%) in 47 (81%) patients. All subjects except one were already treated with reformulated nonacog alfa before enrollment. One subject was receiving reformulated nonacog alfa as immune tolerance induction at time of enrollment. At enrollment, treatment regimen was mainly prophylactic in subjects less than 18 years and on-demand in subjects 18 years or older. Median duration of follow-up in the survey was 3.3 (2.3-3.8) years. The median annualized bleeding rate was 3.9 (1.5-5.2) for prophylaxis regimen and 12.2 (3.9-22.1) for on-demand regimen. One subject, a previously untreated patient, developed F IX inhibitors during follow-up. No allergic reaction, no blood cell agglutination, no lack of efficacy or recovery, and no thrombotic events were reported.

CONCLUSION

Reformulated nonacog alfa was shown to be safe in a usual care setting.

F376A/M388A-solulin, a new promising antifibrinolytic for severe haemophilia A

INTRODUCTION

Haemophilia is a major bleeding disorder due to a deficiency of procoagulant factor VIII (type A) or IX (type B). The treatment is substitutive and based on infusion of factor concentrates. Main limitations of this therapy are cost, short factor half-life and the development of inhibitors (up to 30% of severe HA patients). An important aggravating factor of haemophilia is due to a premature fibrinolysis, directing attention to the therapeutic potential of suitable antifibrinolytics. Thrombomodulin (TM) is a key player of the coagulation cascade by activating protein C (an inhibitor of thrombin generation, thus antagonizing coagulation) and of the fibrinolytic cascade by activating thrombin activatable fibrinolysis inhibitor TAFI (thus reducing fibrinolysis). Solulin is a soluble form of TM that shows both capabilities.

AIM

Here, we developed a new generation of solulin variants (F376A-, M388A- and F376A/M388A-solulin) with a decreased ability to activate protein C and a conserved capacity to activate TAFI.

METHODS

We produced and characterized solulin variants in vitro. In addition, F376A/M388A-solulin was tested ex vivo, using blood samples of haemophilic A patients, with thromboelastography.

RESULTS

The solulin variants (F376A, M388A and the double-mutant F376A/M388A) lost their abilities to activate protein C but are still capable to activate TAFI. Thrombelastography showed increased clot firmness and stability, that, as opposed to wild-type solulin, was maintained even at high concentrations of F376A/M388A-solulin (100 nm).

CONCLUSION

In sum, these results open new opportunities for the development of specific medication for haemophilic patients.

Influence of factor VIII level and its inhibitor titer on the therapeutic response to corticosteroids alone in the management of acquired hemophilia: A retrospective single-center study

The treatment of acquired hemophilia (AH) involves discussing whether corticosteroids should be administered alone or combined with immunosuppressant drugs, which increase the risk of infection especially in elderly patients and/or those with autoimmunity or neoplastic diseases, who represent the target population of the disease. Prognostic factors highlighting adequate responses to corticosteroids alone must be identified for satisfactory clinical response and lower infectious risk.We aimed to evaluating the efficacy of corticosteroids alone in the management of AH depending on factor VIII (FVIII, ≥ or <1 IU/dL) levels and/or inhibitor (INH, ≤ or >20 Bethesda units per milliliter [BU/mL]) titer.We conducted a retrospective single-center study including 24 patients treated for AH with corticosteroids alone.Time to achieve partial remission (PR: absence of hemorrhage and FVIII levels >50 IU/dL) was significantly shorter in the FVIII ≥ 1 IU/dL group than in the FVIII < 1 IU/dL group (20 [10-55] vs 39 [20-207] days, P = 0.044) and in the INH ≤ 20 BU/mL and FVIII ≥ 1 IU/dL group than in the FVIII < 1 IU/dL and/or INH > 20 BU/mL group (15 [11-35] vs 41 [20-207] days, P = 0.003). In both subgroups, time to achieve complete remission (CR: negative INH and corticosteroids below 10 mg/d) was also significantly shorter than that observed in the opposite subgroups. INH titer, considered alone, did not affect the length of time to onset of PR or CR. CR and PR rates did not differ significantly depending on these variables.Our study suggests that in AH, patients with FVIII levels ≥1 IU/dL considered alone or combined with INH titer ≤20 BU/mL could be treated by corticosteroids alone, given that this subgroup of patients displayed faster therapeutic responses to this strategy.

Achievements, challenges and unmet needs for haemophilia patients with inhibitors: Report from a symposium in Paris, France on 20 November 2014

Over the past 20 years, there have been many advances in haemophilia treatment that have allowed patients to take greater control of their disease. However, the development of factor VIII (FVIII) inhibitors is the greatest complication of the disease and a challenge in the treatment of haemophilia making management of bleeding episodes difficult and surgical procedures very challenging. A meeting to discuss the unmet needs of haemophilia patients with inhibitors was held in Paris on 20 November 2014. Topics discussed were genetic and non-genetic risk factors for the development of inhibitors, immunological aspects of inhibitor development, FVIII products and inhibitor development, generation and functional properties of engineered antigen-specific T regulatory cells, suppression of immune responses to FVIII, prophylaxis in haemophilia patients with inhibitors, epitope mapping of FVIII inhibitors, current controversies in immune tolerance induction therapy, surgery in haemophilia patients with inhibitors and future perspectives for the treatment of haemophilia patients with inhibitors. A summary of the key points discussed is presented in this paper.

A Laboratory Phenotype/Genotype Correlation of 1167 French Patients From 670 Families With von Willebrand Disease: A New Epidemiologic Picture

von Willebrand disease (VWD) is a genetic bleeding disease due to a defect of von Willebrand factor (VWF), a glycoprotein crucial for platelet adhesion to the subendothelium after vascular injury. VWD include quantitative defects of VWF, either partial (type 1 with VWF levels <50 IU/dL) or virtually total (type 3 with undetectable VWF levels) and also qualitative defects of VWF (type 2 variants with discrepant antigenic and functional VWF levels). The most bleeding forms of VWD usually do not concern type 1 patients with the mildest VWF defects (VWF levels between 30 and 50 IU/dL). The French reference center for VWD performed a laboratory phenotypic and genotypic analysis in 1167 VWD patients (670 families) selected by their basic biologic phenotype: type 3, type 2, and type 1 with VWF levels <30 IU/dL. In these patients indeed, to achieve an accurate diagnosis of VWD type and subtype is crucial for the management (treatment and genetic counseling). A phenotype/genotype correlation was present in 99.3% of cases; 323 distinct VWF sequence variations (58% of novel) were identified (missense 67% versus truncating 33%). The distribution of VWD types was: 25% of type 1, 8% of type 3, 66% of type 2 (2A: 18%, 2B: 17%, 2M: 19%, 2N: 12%), and 1% of undetermined type. Type 1 VWD was related either to a defective synthesis/secretion or to an accelerated clearance of VWF. In type 3 VWD, bi-allelic mutations of VWF were found in almost all patients. In type 2A, the most frequent mechanism was a hyper-proteolysis of VWF. Type 2B showed 85% of patients with deleterious mutations (distinct from type 2B New York). Type 2M was linked to a defective binding of VWF to platelet glycoprotein Ib or to collagen. Type 2N VWD included almost half type 2N/3. This biologic study emphasizes the complex mechanisms for both quantitative and qualitative VWF defects in VWD. In addition, this study provides a new epidemiologic picture of the most bleeding forms of VWD in which qualitative defects are predominant.

A novel ELISA-based diagnosis of acquired von Willebrand disease with increased VWF proteolysis

Von Willebrand disease-type 2A (VWD-2A) and acquired von Willebrand syndrome (AVWS) due to aortic stenosis (AS) or left ventricular assist device (LVAD) are associated with an increased proteolysis of von Willebrand factor (VWF). Analysis of VWF multimeric profile is the most sensitive way to assess such increased VWF-proteolysis. However, several technical aspects hamper a large diffusion among routine diagnosis laboratories. This makes early diagnosis and early appropriate care of increased proteolysis challenging. In this context of unmet medical need, we developed a new ELISA aiming a quick, easy and reliable assessment of VWF-proteolysis. This ELISA was assessed successively in a LVAD-model, healthy subjects (n=39), acquired TTP-patients (n=4), VWD-patients (including VWD-2A(IIA), n=22; VWD-2B, n=26; VWD-2A(IIE), n=21; and VWD-1C, n=8) and in AVWS-patients (AS, n=9; LVAD, n=9; and MGUS, n=8). A standard of VWF-proteolysis was specifically developed. Extent of VWF-proteolysis was expressed as relative percentage and as VWF proteolysis/VWF:Ag ratio. A speed-dependent increase in VWF-proteolysis was assessed in the LVAD model whereas no proteolysis was observed in TTP-patients. In VWD-patients, VWF-proteolysis was significantly increased in VWD-2A(IIA) and VWD-2B and significantly decreased in VWD-2A(IIE) versus controls (p< 0.0001). In AVWS-patients, VWF-proteolysis was significantly increased in AS- and LVAD-patients compared to controls (p< 0.0001) and not detectable in MGUS-patients. A significant increase in VWF-proteolysis was detected as soon as three hours after LVAD implantation (p< 0.01). In conclusion, we describe a new ELISA allowing a rapid and accurate diagnosis of VWF-proteolysis validated in three different clinical situations. This assay represents a helpful alternative to electrophoresis-based assay in the diagnosis and management of AVWS with increased VWF-proteolysis.

Development of inhibitory antibodies to therapeutic factor VIII in severe hemophilia A is associated with microsatellite polymorphisms in the HMOX1 promoter

Induction of heme oxygenase-1, a stress-inducible enzyme with anti-inflammatory activity, reduces the immunogenicity of therapeutic factor VIII in experimental hemophilia A. In humans, heme oxygenase-1 expression is modulated by polymorphisms in the promoter of the heme oxygenase-1-encoding gene (HMOX1). We investigated the relationship between polymorphisms in the HMOX1 promoter and factor VIII inhibitor development in severe hemophilia A. We performed a case-control study on 99 inhibitor-positive patients and 263 patients who did not develop inhibitors within the first 150 cumulative days of exposure to therapeutic factor VIII. Direct sequencing and DNA fragment analysis were used to study (GT)n polymorphism and single nucleotide polymorphisms located at -1135 and -413 in the promoter of HMOX1. We assessed associations between the individual allele frequencies or genotypes, and inhibitor development. Our results demonstrate that inhibitor-positive patients had a higher frequency of alleles with large (GT)n repeats (L: n≥30), which are associated with lesser heme oxygenase-1 expression (odds ratio 2.31; 95% confidence interval 1.46-3.66; P<0.001]. Six genotypes (L/L, L/M, L/S, M/M, M/S and S/S) of (GT)n repeats were identified (S: n<21; M: 21≤n<30). The genotype group including L alleles (L/L, L/M and L/S) was statistically more frequent among inhibitor-positive than inhibitor-negative patients, as compared to the other genotypes (33.3% versus 17.1%) (odds ratio 2.21, 95% confidence interval 1.30-3.76; P<0.01). To our knowledge, this is the first association identified between HMOX1 promoter polymorphism and development of anti-drug antibodies. Our study paves the way towards modulation of the endogenous anti-inflammatory machinery of hemophilia patients to reduce the risk of inhibitor development.

Hydrolysis of factor VIII mediated by catalytic antibodies occurs in haemophilia A patients with or without factor VIII inhibitors

The major complication of the substitutive treatment of haemophilia A (HA) is the development of antifactor VIII (FVIII) antibodies. Most of these antibodies neutralize FVIII procoagulant activity, and are identified as FVIII inhibitor. A subgroup of these antibodies, 'catalytic antibodies', catalyses the FVIII hydrolysis. We investigated the frequency and the activity of catalytic antibodies, according to the phenotype of HA and the presence or absence of FVIII inhibitor. IgG from 16 patients with inhibitor and 17 patients without inhibitor were purified. Rates of FVIII hydrolysis and inhibitor titres were evaluated. Anti-FVIII catalytic antibodies were detected in 63.6% of patients with HA, irrespective of the HA phenotype and the presence of FVIII inhibitor. The frequency was significantly higher for severe HA patients (73.3%) and patients with inhibitor (87.5%), but their FVIII-proteolytic activity was not significantly different from patients with mild or moderate HA and patients without inhibitor. The evolution of both catalytic and inhibitory activities was studied for 11 patients with FVIII inhibitor. We observed two profiles. In the profile 1, 18.2% of patients, the catalytic activity and the inhibitor titre coevolved. In contrast, a dissociated evolution of these two parameters was observed in 72.8% patients in profile 2. These data confirm the importance of anti-FVIII catalytic activity in patients with severe, moderate and mild HA. Interestingly, most of the patients presented a dissociated profile, suggesting that anti-FVIII antibodies might not systematically act as FVIII inhibitors.

Patient resources in the therapeutic education of haemophiliacs in France: their skills and roles as defined by consensus of a working group

The activities of 'expert patients' or 'patient tutors', who help educate their peers, are gaining recognition in the health care system. This study investigates the role played by such patients in therapeutic education programmes organized by caregivers to validate the role of patients in implementing the therapeutic education of haemophilic patients and to define the skills required for such activities. This study employs the consensus methodology recommended by France's National Authority for Health. The working group includes seven caregivers from Hemophiliac Treatment Centers (HTCs) and three patients from the French Association of Hemophiliacs (FAH). The role of patients in haemophilia education is recognized. Patients participating in the education of their peers are referred to as 'patient resources'. A patient resource should be an adult, a volunteer and live in the same region as his peers. Candidates are chosen by the FAH and the HTCs to serve based on their motivation to facilitate the education of other patients as well as on their psychological and pedagogical aptitudes. A patient resource participates in the conception and administration of therapeutic education programmes. He also mediates between the caregivers and the patients. He ensures that the patients understand the material and are able to apply their knowledge in daily life. His activities are governed by professional ethics. Seven categories of skills were defined, permitting the group to determine precisely which skills are required to function as a patient resource. Supervision of the patients is planned to reinforce reflexive practices in the patients. Evolution of the health care system has led patients to become involved in therapeutic education. This phenomenon calls for a framework to be developed and an evaluation of its eventual effects.

[French guidelines. Long-term prophylaxis for severe haemophilia A and B children to prevent haemophiliac arthropathy]

During the last decades, long-term prophylaxis has become the gold standard for the treatment of children with severe haemophilia A or B. Prophylactic replacement regimens modify the natural history of the disease by aiming at the prevention of haemarthrosis, target joints and arthropathy. This treatment represents a constraint and an enhanced exposure to anti-haemophilic concentrates, which means potential increase of related risks and significant additional cost. The context of crisis of confidence due to the blood borne infections in the 1980s, may have delayed prophylaxis as an universal gold standard.In the early 2000s, the French group CoMETH proposed recommendations based on the review of the international experience. At first, specific guidelines of long-term prophylaxis were dedicated to children with severe haemophilia A or B, aged 3 years or less, with no history of target joint or arthropathy. The main concerns of this regimen consist in the early start and the escalating intensification of the treatment. In the French haemophilia care centres, the diffusion of these guidelines has apparently induced a significant turning point in therapeutic practices for haemophilia children. In 2006, more comprehensive recommendations were diffused to take into account all the children with severe haemophilia, whatever the bleeding history and joint status. The analysis of their impact, jointly with the National cohort "France Coag Network", will first assess the widespread implementation of the recommendations and the observance of the prophylactic regimen and identify factors associated to the compliance.

[Acquired von Willebrand syndrome: from diagnosis to treatment]

Acquired von Willebrand syndrome is a rare bleeding disorder, which has been related in various diseases including lymphoproliferative disorders or autoimmune diseases. Its diagnosis is an important step before treatment of patients and particularly in case of bleeding. We report four cases from Caen Hemophilia Treatment Center, diagnosed and treated from 1999 to 2008. Mucocutaneous bleeds in every case were the same as in hereditary von Willebrand disease. All patients had no personal or family history of bleeding. Phenotype was identified as type 2 von Willebrand disease with a loss of high molecular weight multimers. Anti-von Willebrand factor inhibitor screening was positive for three patients. The etiological diagnosis was one chronic lymphocytic leukaemia, two monoclonal gammapathies of undetermined significance (MGUS) and one undetermined case. The management of patients need two stages: first infusions of factor von Willebrand/factor VIII concentrates to stop bleeds, then treatment of the underlying disease such as chemotherapy, corticotherapy and treatment with high doses of polyvalents immunoglobulins. In every case, treatment was effective and improved patient's quality of life.

Prophylactic treatment of haemophilia patients with inhibitors: clinical experience with recombinant factor VIIa in European Haemophilia Centres

Many patients with haemophilia develop inhibitors to factor VIII and require bypassing agents to provide haemostatic cover for limb- or life-threatening bleeding episodes. Due to the reduced risk of blood-borne pathogen transmission with recombinant products, on-demand recombinant factor VIIa (rFVIIa; NovoSeven is the treatment of choice for children with inhibitors. In haemophiliac patients without inhibitors, primary prophylaxis has been clinical practice for several years. This paper summarises 13 case histories of rFVIIa secondary prophylaxis for haemophilia patients with inhibitors. This was a retrospective survey of adult and paediatric severe haemophilia patients with inhibitors treated with rFVIIa from ten European Haemophilia Centres. There was a wide variation in administered rFVIIa dose, from 200-250 microg kg(-1) per week to 220 microg kg(-1) daily. In many cases, this was lower than the recommended on-demand dose of rFVIIa. In 12/13 cases, prophylaxis with rFVIIa considerably reduced the number of bleeding episodes compared with previous treatment. Eight/nine patients were satisfied or very satisfied with rFVIIa treatment, and in cases reporting subjective quality of life (QoL), all were improved, much improved, or significantly improved. In haemophilia patients with inhibitors, prophylaxis with rFVIIa is highly effective in reducing the number of bleeding episodes and results in good patient compliance and improved QoL. Randomised controlled trials are needed to confirm these findings. Results of a recently completed clinical trial on secondary prophylaxis with rFVIIa in frequently bleeding haemophilia patients with inhibitors are expected in late 2006.

Factor VIII (FVIII) gene mutations in 120 patients with hemophilia A: detection of 26 novel mutations and correlation with FVIII inhibitor development

BACKGROUND

As the publication of the sequence of the factor VIII gene (FVIII) in 1984, a large number of mutations that cause hemophilia A (HA) have been identified. Thanks to the advances in the detection of mutations, it is now possible to identify a putative FVIII sequence alteration in the vast majority of patients with HA.

OBJECTIVES

Our main objective was to report on the spectrum of FVIII mutations and their distribution throughout the gene in 120 patients with HA.

METHODS

Screening of FVIII mutations was performed using direct sequencing. Newly described missense mutations were further studied by molecular modeling.

RESULTS

A total of 47 different HA causative FVIII mutations have been identified, 26 of which are described for the first time. These novel mutations include 14 missense and six nonsense mutations, two small deletions, one large deletion and three splice-site mutations. We further investigated the development of FVIII-specific inhibitors in all patients with HA. We found that four novel mutations (Ser882X, Tyr1786Ser, Ala2218Thr and a splice-site defect in intron 22) were associated with inhibitor development.

CONCLUSION

These data extend our insight into the mechanisms by which novel amino acid substitutions may lead to HA, and how HA patient genotypes influence the risk of FVIII inhibitor development.

Treatment of severe von Willebrand disease with a high-purity von Willebrand factor concentrate (Wilfactin): a prospective study of 50 patients

BACKGROUND AND OBJECTIVES

A plasma-derived von Willebrand factor (VWF) concentrate with low factor VIII (FVIII) content was specifically developed to treat von Willebrand disease (VWD). Efficacy and safety were investigated by merging the results of two comparable protocols conducted prospectively in 5 European and 12 French centers.

METHODS AND RESULTS

Fifty patients with clinically severe VWD (72% had VWF ristocetin cofactor activity less than 10 IU dL(-1) and 46% had FVIII < 20 IU dL(-1)) were treated with the concentrate as the only therapy, except for clinical situations requiring a priming dose of FVIII to rapidly correct an intrinsic coagulation defect. A total of 139 spontaneous bleeding episodes were treated; only 53 (38%) needed a concomitant FVIII dose. Outcome was excellent or good in 89% of the episodes. Forty-four patients underwent 108 surgical or invasive procedures. Outcome was excellent or good in 95 scheduled procedures (only VWF was infused) and 13 emergency procedures (a priming FVIII dose was co-administered with the first VWF infusion). There were no thrombotic complications and none of the 18 patients with type 3 VWD developed anti-VWF or anti-FVIII antibodies.

CONCLUSIONS

This concentrate safely and effectively provides hemostasis in patients with clinically severe VWD.

VWF protects FVIII from endocytosis by dendritic cells and subsequent presentation to immune effectors

Von Willebrand factor (VWF) is a chaperone molecule for procoagulant factor VIII (FVIII). Its role in the reduction of the immunogenicity of therapeutic FVIII in patients with hemophilia A has been evoked but lacks clear cellular and molecular rationale. Here, we demonstrate that VWF protects FVIII from being endocytosed by human dendritic cells (DCs) and subsequently presented to FVIII-specific T cells. The immunoprotective effect of VWF requires a physical interaction with FVIII because the endocytosis of FVIII was significantly restored on hindering the formation of the VWF-FVIII complex. Interestingly, VWF had no direct inhibitory effect either on the ability of DCs to present antigenic peptides or on the activation potency of CD4+ T cells. We thus propose that VWF may reduce the immunogenicity of FVIII by preventing, upstream from the activation of immune effectors, the entry of FVIII in professional antigen-presenting cells.

Influence of the type of factor VIII concentrate on the incidence of factor VIII inhibitors in previously untreated patients with severe hemophilia A

Inhibitor development is the major treatment complication in children with severe hemophilia A. It is not clear whether the risk of inhibitors is higher with recombinant factor VIII or with plasma-derived factor VIII. We used multivariate analysis to compare 2 cohorts of previously untreated patients (PUPs) with severe hemophilia A: 62 patients treated with the same brand of high-purity plasma-derived FVIII (pFVIII) containing von Willebrand factor (VWF) and 86 patients treated with full-length recombinant FVIII (rFVIII). In addition to the usual end points (all inhibitors, high inhibitors), we also examined a third end point (high inhibitors and/or immune tolerance induction). The risk of inhibitor development was higher in patients treated with rFVIII than in patients treated with pFVIII, regardless of other risk factors (F8 genotype; nonwhite origin; history of inhibitors in patients with a family history of hemophilia; age at first FVIII infusion). The adjusted relative risk (RRa) for inhibitor development with rFVIII versus pFVIII was 2.4 (all inhibitors), 2.6 (high inhibitors), and 3.2 (high inhibitors and/or immune tolerance induction), respectively, depending on the end point (above). The pathophysiology of this large effect must be understood in order to improve the characteristics of recombinant products and to reduce the incidence of inhibitors to FVIII.

Impact of Choice of Treatment for Bleeding Episodes on Inhibitor Outcome in Patients With Mild/Moderate Hemophilia A and Inhibitors

Patients with mild/moderate hemophilia A (MHA) may develop inhibitors to factor VIII (FVIII). In this condition, FVIII clotting activity (FVIII:C) baseline levels may remain stable for some patients, but may be reduced to less than 0.01 U/mL for others. Several risk factors for the development of inhibitors in MHA have been proposed. Genetic factors, such as mutations in the FVIII gene, may play a central role; however, other influences, such as intensive treatment with FVIII products, may also be important. Optimal treatment regimens have yet to be determined, not only for the eradication of inhibitors, but also for the management or surgical prophylaxis of hemorrhages associated with this condition. Several treatment options for the control of bleeding in patients with MHA and inhibitors (MHAI) are currently available, and the choice of therapeutic strategy should be given careful consideration; some treatments may produce an anamnestic response, thus delaying the return to FVIII:C baseline levels and adversely affecting the duration of the severe bleeding phenotype. To increase our knowledge of MHAI, a retrospective collection of data is currently being performed among hemophilia centers in France and Belgium. Based on five examples of patients with MHAI collated from preliminary study data, we illustrate the impact on inhibitor outcome of the therapeutic choices used to treat bleeding episodes in these patients.

Pharmacokinetic studies on Wilfactin, a von Willebrand factor concentrate with a low factor VIII content treated with three virus-inactivation/removal methods

OBJECTIVE

In order to correct the primary von Willebrand factor (VWF) defect and avoid supra-physiologic plasma levels of factor VIII, a pure VWF concentrate almost devoid of FVIII was developed and used in France since 1989.

METHODS

The pharmacokinetic (PK) profile of the most recent version of this concentrate (Wilfactin; LFB, Les Ulis, France), treated with three virus-inactivation/removal methods (solvent/detergent, 35 nm filtration, dry heat treatment), was investigated in 25 patients. Seventeen patients with various types of clinically severe von Willebrand disease (VWD) were included in a crossover, randomized trial carried out in five European centers and comparing Wilfactin with concentrates containing both FVIII and VWF (FVIII/VWF). Eight type 3 VWD patients were included in another trial carried out in six French centers comparing Wilfactin with its previous version (Facteur Willebrand-LFB; LFB) that adopted one virus-inactivation method only.

RESULTS

For both the measurements evaluated in this study (VWF antigen, VWF:Ag; and VWF ristocetin co-factor activity, VWF:RCo), Wilfactin had a PK profile similar to that of the FVIII/VWF concentrates and of Facteur Willebrand-LFB. VWF:RCo and VWF:Ag recoveries were 2.1 +/- 0.3 and 1.8 +/- 0.3 per IU kg(-1), respectively, and the half-lives were 12.4 +/- 1.8 and 15.9 +/- 1.5 h. The FVIII synthesis rate was 5.8 +/- 1.0 IU dL(-1) h(-1), with a half-life of 15.8 +/- 2.4 h.

CONCLUSION

The PK of VWF and FVIII have not been altered by the three virus-inactivation/removal steps during the manufacturing of Wilfactin.

Intestinal surgery with activated recombinant factor VII prophylaxis in patients with haemophilia A and high responding inhibitors

Five patients with severe haemophilia A and high responding inhibitors underwent laparoscopic or open surgery on the digestive tract (appendicectomy, cholecystectomy, partial colectomy, or haemorrhoidectomy) with recombinant activated factor VII (rFVIIa) prophylaxis. rFVIIa was administered at a dose of 92-127 mug/kg prior to surgery and then every 2 h for 18-56 h before increasing the dosing interval. One patient was switched to a continuous infusion after 48 h of rFVIIa boluses. rFVIIa treatment lasted between 5 and 14 days in four patients, with good or excellent efficacy (total dose, 3.13-9.28 mg/kg). The fifth patient, who underwent surgery for prolapsed haemorrhoids, bled on day 6 and day 10 after the procedure, despite a satisfactory prothrombin time and factor VII coagulant level. The rFVIIa dose regimen was increased after the second bleeding episode, then the bleeding rapidly ceased after this modification to the treatment regimen. The total dose of rFVIIa used was 12.65 mg/kg, and treatment lasted 17 days. Antifibrinolytic treatment was used concomitantly in all five patients. Clinical and biological tolerability was excellent, and no increase in the anti-factor VIII inhibitor titre was observed. These results suggest that rFVIIa prophylaxis is effective in haemophilia A patients with factor VIII inhibitors who are undergoing elective or emergency intestinal surgery. Further studies are required to optimize the dose regimen and treatment period according to the surgical indication and technique.

Experience with use of recombinant activated factor VII

Recombinant activated factor VII (rFVIIa) has recently been introduced for improving haemostasis in haemophiliac patients developing alloantibodies (inhibitors) to factor VIII (FVIII) or factor IX (FIX). We describe the successful management of haemorrhagia with rFVIIa in five different situations: an episode of surgical bleeding in a patient with haemophilia A and non-surgical haemorrhages in four patients with haemophilia A, acquired haemophilia, congenital severe FV defect and pseudo-acquired haemophilia, respectively. In each case, rFVIIa was effective and safe. There is no doubt that rFVIIa is useful in the therapeutic management of patients with antibodies to FVIII or FIX. However, the treatment is expensive and a cost-effectiveness analysis would be useful.

Venous thromboembolism during pregnancy: a retrospective study of enoxaparin safety in 624 pregnancies

OBJECTIVE

To assess the maternal, fetal and neonatal safety of enoxaparin in pregnant women who require antithrombotic therapy.

DESIGN

Retrospective analysis of case notes of women who received enoxaparin during pregnancy, irrespective of dose, duration and reason for treatment.

SETTING

Fifty-five French perinatal centres.

SAMPLE

Data from 624 pregnancies in 604 women between 1988 and 1997. The incidence of previous thromboembolism was 29.8%, known thrombophilia 15.2%.

METHODS

Indication, regimen of enoxaparin and outcome measures were reported for each pregnancy. Information was obtained from case records, validated by research staff and analysed by an independent scientific committee.

MAIN OUTCOME MEASURES

Incidence, seriousness and causality of maternal, fetal and neonatal adverse events, pregnancy outcome, and incidence of venous thromboembolism.

RESULTS

Enoxaparin was administered for treatment of an acute episode in 49 cases and for thromboprophylaxis in 574 cases. Serious maternal haemorrhage occurred in 11 cases during pregnancy (1.8%), one being reasonably related to enoxaparin, and in nine cases at delivery (1.4%), all unrelated to enoxaparin. Maternal thrombocytopenia was reported in 10 cases (1.6%). two being serious but unrelated to enoxaparin. Eight pregnancies ended in stillbirth (1.1%). Among the 693 live births, 17 major congenital abnormalities (2.5%) and 10 serious neonatal haemorrhages (1.4%) were reported. None of the fetal or neonatal adverse events was related to enoxaparin. Eight venous thromboembolic events (1.3%) were reported.

CONCLUSIONS

The incidence of adverse events reported could be explained by the high risk profile of the study population. Overall, this retrospective study suggests enoxaparin is well tolerated during pregnancy.

Platelet ultrastructural abnormalities in three patients with type 2B von Willebrand disease

Several reports have described the presence of giant platelets in patients with type 2B von Willebrand disease (VWD). We have now characterized the ultrastructural changes in platelets from three unrelated patients with type 2B VWD and different mutations within exon 28 of the von Willebrand factor (VWF) gene. Electron microscopy showed that each of these subjects had an increased proportion of large platelets when compared with those of a patient with type 2A VWD or control subjects. Immunogold labelling for VWF was performed. Large masses detected by anti-VWF antibody were seen not only on the platelet surface, but also inside the platelet surface-connected canalicular system (SCCS) when ultrathin sections were labelled. This suggested translocation of the abnormally bound VWF from the platelet surface. Labelling of the alpha-granules was eccentric as for normal platelets. Labelling for glycoprotein (GP) Ib was seen on the surface and within the SCCS, suggesting co-localization with the bound VWF. However, there was no evidence for VWF in endosomes or other endocytic vesicles. The presence of platelet-bound VWF was not accompanied by high levels of platelet activation, as detected by electron microscopy, or by using monoclonal antibodies against P-selectin or activation-dependent determinants on GP IIb-IIIa in flow cytometry. Intriguingly, platelet ultrastructure often resembled that seen in patients with congenital thrombocytopathies characteristic of giant platelet syndromes.

Three cases of acquired von Willebrand disease associated with systemic lupus erythematosus

Acquired von Willebrand disease associated with systemic lupus erythematosus (SLE) has been detected in three middle-aged women. In each case the first clinical manifestation was a bleeding syndrome. Plasma levels of von Willebrand factor (VWF) and ristocetin-induced platelet agglutination were as found in type 1 von Willebrand disease for the first patient, type 3 for the second patient, and type 2 for the third patient. Intraplatelet levels of VWF were normal for all three patients. In all cases a mixture of patient's plasma with normal plasma resulted in inhibition of ristocetin-induced binding of VWF to normal platelets. Intravenous immunoglobulin given to patients 2 and 3 corrected the plasma VWF level of the second patient but not that of the third. Therapy with corticosteroids was partially beneficial for patient 3 and patient 2. For patient 2, the severity of the cutaneous lesions also led to the use of cyclophosphamide, and this therapy resulted in total correction of VWF levels. Our observations confirm previous reports of acquired von Willebrand syndrome associated with SLE and show heterogeneity both in the phenotypic form and in the response to treatment.

[Which perioperative therapeutic strategies in constitutional hemostasis disorders?]

Type A and B haemophilias and von Willebrand's disease are the most common haemostasis disorders. Haemorrhage risks during both surgery and the time period surrounding surgery are often associated with these diseases. Consequently, normalization of the plasma level of the lacking protein and adapted therapeutic management will be the main objectives. Before undertaking any surgical procedure, the interview with the anaesthesiologist will allow detection of the disease. The type and the severity of the deficit at the origin of perioperative haemorrhage risks may be determined in collaboration with appropriate treatment centers. Therapeutic procedures (under the form of a protocol) will thus be defined. This multidisciplinary approach will make any surgical procedure feasible, whatever the type of haemostasis disorder.

[Digestive hemorrhage disclosing an angiodysplasia and von Willebrand disease type 2]

The authors report a case of a 76-year-old man, with not past history of abnormal bleeding, who suffered an acute, recurrent, intestinal haemorrhage from extensive angiodysplasia of the colon. Intestinal bleeding and angiodysplasia were associated with a von Willebrand's disease. Genetic analysis showed a point mutation in arginine 611 of the mature von Willebrand's factor subunit (A1 loop) confirming a von Willebrand's disease type 2.