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BACKGROUND: Type 2 Normandy von Willebrand disease (VWD2N) is usually perceived as a mild bleeding disorder that can be treated with desmopressin (DDAVP). However, VWD2N patients can be compound heterozygous or homozygous for different variants, with p.Arg854Gln (R854Q) being the most frequent causative one. There are limited data about the impact of 2N variants on VWD2N phenotype and DDAVP response. OBJECTIVES: This study aims to describe the phenotype of VWD2N, including DDAVP response, according to genotype. METHODS: VWD2N patients with a complete genotype/phenotype characterization by the French reference center for VWD, including MCMDM-1VWD bleeding score, were eligible to be included in the study. Results of the DDAVP trial were also collected. RESULTS: A total of 123 VWD2N patients from the French registry were included in this study. Results were stratified according to the presence (R854QPos, n = 114) or absence (R854QNeg, n = 9) of at least 1 R854Q allele. Three R854QPos subgroups were further individualized: patients homozygous (R854QHmz, n = 55), compound heterozygous for R854Q and a null allele (R854Q/3, n = 48), or compound heterozygous for R854Q and another 2N variant (R854Q/2N, n = 11). FVIII: C levels were significantly lower in R854QNeg and R854Q/3 patients compared with R854QHmz ones (P < .001 and P < .0001, respectively). R854QNeg patients were diagnosed earlier due to bleeding symptoms and had a higher bleeding score than R854QPos patients (P < .001). In DDAVP trial, FVIII:C survival was lower in VWD type 2N than in type 1 patients. R854QPos patients had a heterogeneous DDAVP response, which was best predicted by baseline FVIII:C level. CONCLUSION: The heterogeneous genetic background of VWD2N drives different bleeding phenotypes and response patterns to DDAVP, underlining the clinical relevance of DDAVP trial to identify patients potentially eligible to alternative therapeutic options.
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INTRODUCTION: Bleeding severity in severe haemophilic patients, with low thrombin generation (TG) capacity, can vary widely between patients, possibly reflecting differences in tissue factor pathway inhibitor (TFPI) level. AIM: To compare free TFPI (fTFPI) levels in patients with severe haemophilia A (sHA) and severe haemophilia B (sHB) and to investigate in these patients as a whole the relationships between bleeding and TG potential, between TG potential and fTFPI level and between fTFPI level and bleeding tendency. METHODS: Data on bleeding episodes retrospectively recorded during follow-up visits over 5-10 years were collected and used to calculate the annualised joint bleeding rate (AJBR). fTFPI levels and basal TG parameters were determined in platelet-poor plasma (PPP) and platelet-rich plasma (PRP) using calibrated automated tomography (CAT). RESULTS: Mean fTFPI levels did not differ significantly between sHA (n = 34) and sHB (n = 19) patients. Mean values of endogenous thrombin potential (ETP) and thrombin peak (peak) in PPP and PRP were two-fold higher when fTFPI levels < 9.4 versus > 14.3 ng/mL. In patients treated on demand, ETP and peak in PRP were doubled when AJBR was ≤ 4.9 $ \le 4.9$ , AJBR being halved in patients with a low fTFPI level (9.4 ng/mL). In patients on factor prophylaxis, no association was found between TG parameters and either fTFPI level or AJBR. CONCLUSION: In patients treated on demand, bleeding tendency was influenced by fTFPI levels, which in turn affected basal TG potential. In patients on prophylaxis, bleeding tendency is probably determined primarily by the intensity of this treatment.
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Hemofilia A , Hemofilia B , Hemorragia , Lipoproteínas , Trombina , Humanos , Hemofilia A/complicaciones , Hemofilia A/sangre , Trombina/metabolismo , Hemofilia B/complicaciones , Hemofilia B/sangre , Hemorragia/etiología , Hemorragia/sangre , Masculino , Lipoproteínas/sangre , Adulto , Adulto Joven , Persona de Mediana Edad , Adolescente , Estudios Retrospectivos , Femenino , Niño , Índice de Severidad de la Enfermedad , Preescolar , AncianoRESUMEN
BACKGROUND: No F8 genetic abnormality is detected in approximately 1% to 2% of patients with severe hemophilia A (HA) using conventional genetic approaches. In these patients, deep intronic variation or F8 disrupting genomic rearrangement could be causal. OBJECTIVES: The study aimed to identify the causal variation in families with a history of severe HA for whom genetic investigations failed. METHODS: We performed whole F8 gene sequencing in 8 propositi. Genomic rearrangements were confirmed by Sanger sequencing of breakpoint junctions and/or quantitative polymerase chain reaction. RESULTS: A structural variant disrupting F8 was found in each propositus, so that all the 815 families with a history of severe HA registered in our laboratory received a conclusive genetic diagnosis. These structural variants consisted of 3 balanced inversions, 3 large insertions of gained regions, and 1 retrotransposition of a mobile element. The 3 inversions were 105 Mb, 1.97 Mb, and 0.362 Mb in size. Among the insertions of gained regions, one corresponded to the insertion of a 34 kb gained region from chromosome 6q27 in F8 intron 6, another was the insertion of a 447 kb duplicated region from chromosome 9p22.1 in F8 intron 14, and the last one was the insertion of an Xq28 349 kb gained in F8 intron 5. CONCLUSION: All the genetically unsolved cases of severe HA in this cohort were due to structural variants disrupting F8. This study highlights the effectiveness of whole F8 sequencing to improve the molecular diagnosis of HA when the conventional approach fails.
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Inversión Cromosómica , Factor VIII , Hemofilia A , Intrones , Fenotipo , Humanos , Hemofilia A/genética , Hemofilia A/diagnóstico , Factor VIII/genética , Masculino , Predisposición Genética a la Enfermedad , Índice de Severidad de la Enfermedad , Linaje , Cromosomas Humanos Par 6/genética , Análisis Mutacional de ADN , Cromosomas Humanos Par 9/genética , Análisis de Secuencia de ADN , Mutación , FemeninoRESUMEN
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.
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INTRODUCTION: Since June 2021 in France, patients with haemophilia A with anti-factor VIII inhibitors and patients with severe haemophilia A without anti-factor VIII inhibitors, and treated with emicizumab (Hemlibra), have to choose the dispensing circuit community or hospital pharmacy. AIM: To evaluate satisfaction of patients whether they choose dispensation from a community pharmacy or retained dispensation from the hospital pharmacy, to understand the main motivation for choosing the community or the hospital pharmacy. METHODS: All patients living in France, regardless of age, were eligible to participate. Between September 13, 2022, and January 9, 2023, 175 respondents answered the satisfaction survey, including 123 in community pharmacy and 52 in hospital pharmacy. RESULTS: Eighteen months after availability in community pharmacies, treatment accessibility is improved for the benefit of the patient. The door-to-door travel times are significantly reduced to the community pharmacy with an average gain of 16.5 min saved from the place of residence. Patients are mostly satisfied with the new dispensing circuit especially concerning the overall satisfaction (p < .0001), the travel time (p < .0001) and the strong relationship with the pharmacist (p = .0022) compared to hospital pharmacy. CONCLUSION: Innovation in care pathways is showing its full potential in improving access to medication, made possible by the implementation of a rigorous organization accompanied by training to enable healthcare professionals involved in primary care to provide appropriate management.
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Hemofilia A , Farmacias , Humanos , Satisfacción del Paciente , Vías Clínicas , Hemofilia A/tratamiento farmacológico , Encuestas y Cuestionarios , HospitalesRESUMEN
Background: We aimed to investigate the impact of the first COVID-19 lockdown on medication adherence, physician access, lifestyle behaviours, and mental health in patients with chronic conditions. Methods: A cross-sectional phone survey was conducted in 1274 housebound adults recruited from 8 regional chronic disease cohorts (CLEO CD study: NCT04390126). Results: Medication adherence was 97%; 305 (41%) patients declared that at least one scheduled visit with a physician was missed during the first lockdown. The main changes in lifestyle behaviours were deterioration in sleep time (duration and/or quality; 71%), increase in screen time (46%), and decrease in physical activity (46%). Nineteen percent experienced psychological distress (Kessler-6 score ≥ 5). An urban living place (OR, 1.76 vs. rural; 95% CI, 1.32−2.33; p = 10−4), worse self-reported mental health (OR, 1.62 vs. about the same or better; 95% CI, 1.17−2.25; p = 0.003), and a K6 score ≥ 5 (OR, 1.52 vs. <5; 95% CI, 1.05−2.21; p = 0.03) were independent factors associated with at least one unhealthy behaviour. Conclusions: Encouraging results were observed in terms of medication adherence. Caution is needed in chronic disease patients living in urban places as well as those presenting psychological distress and worse self-reported mental health to reduce unhealthy behaviours.
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COVID-19 , Adulto , COVID-19/epidemiología , Enfermedad Crónica , Control de Enfermedades Transmisibles , Estudios Transversales , Humanos , Estilo de VidaRESUMEN
INTRODUCTION: The coronavirus disease 2019 (COVID-19) pandemic has created an unprecedented global health crisis. AIM: To investigate the impact of the 1st COVID-19 lockdown on haemophilia patients in terms of symptoms, management, medication adherence, mental health and lifestyle behaviours. METHODS: A prospective cross-sectional phone survey using a two-part questionnaire was conducted in haemophilia patients (adults and children) followed-up in a French Haemophilia Comprehensive Care Centre between May 5, 2020 and June 2, 2020 (CLEO CD study: NCT04390126). RESULTS: Among 284 haemophilia A or B patients with FVIII or FIX < 40% contacted for the study, 239 (84%) including 183 adults and 56 children participated to the survey. In 81% of children and 78% of adults, bleeding episodes remained unchanged or decreased. Medication adherence was 82.0% in adults and 98.2% in children. Non-adherence concerned haemostatic agents in six patients and analgesics in three. Overall, 67% of adults and 71% of children felt as good as before lockdown. In both adults and children, the three major changes in lifestyle behaviours were: increase in screen time (49% and 57%), decrease in physical activity (43% and 48%), and weight gain (32% and 27%), respectively. CONCLUSIONS: Encouraging results were observed in terms of haemophilia symptoms, medication adherence, and mental health. Conversely, a negative impact was observed on lifestyle behaviours in a cohort of French haemophilia patients during the 1st lockdown.
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COVID-19 , Hemofilia A , Adulto , COVID-19/epidemiología , Niño , Control de Enfermedades Transmisibles , Estudios Transversales , Hemofilia A/epidemiología , Humanos , Estudios ProspectivosRESUMEN
BACKGROUND: Data are limited on prostate cancer (PC) management in patients with haemophilia (PWH). AIM: To describe PC screening and diagnosis, treatment modalities and bleeding complications in a group of unselected PWH followed at French Haemophilia Treatment Centres (HTCs) PATIENTS AND METHODS: PC screening, management and bleeding complications were retrospectively investigated at 14 French HTCs between 2003 and 2018. RESULTS: Among> 1549 > 50-year-old PWHs, 73 (4.7%) underwent PC screening (median age 71.1 years; 67/6â¯HA/HB, 17/56 severe-moderate/mild). At diagnosis, haematuria was infrequent. Prophylaxis was administered during 76/86 (88%) prostate biopsies (PB) (n = 67 clotting factor concentrates, CFC; n = 9 desmopressin; n = 17 associated with tranexamic acid, TA). Bleeding (11/86, 12.8%) occurred mainly post-prophylaxis (median delay: 7 days): haematuria (9/11, 81.8%), and rectal bleeding (2/11, 18.2%) including one major (1.2%). PC was confirmed in 50/86 PB and in two prostatectomy specimens (total n = 50 patients, n = 6 with only active surveillance). Surgery (n = 28/44 patients) was managed with CFC. Fifteen patients had radiotherapy/brachytherapy, 10â¯had hormone therapy; CFC-based prophylaxis was only prescribed for brachytherapy (n = 2). Major bleedings occurred in 3/28 (10.7%) and 2/15 (13.3%) patients who underwent surgery and radio/brachytherapy, respectively. No bleeding risk factor was found. CONCLUSION: Our data indicate that PB requires prophylaxis for atleast 7 days, using CFC, desmopressin or TA in function of haemophilia severity. PC surgery should be considered at high bleeding risk. Long-term post-procedural CFC or oral TA could be discussed. Radiotherapy/brachytherapy also should be managed with prophylaxis (CFC or TA).
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Hemofilia A , Neoplasias de la Próstata , Anciano , Biopsia , Desamino Arginina Vasopresina/uso terapéutico , Hematuria/complicaciones , Hemofilia A/complicaciones , Hemofilia A/tratamiento farmacológico , Hemorragia/complicaciones , Hemorragia/prevención & control , Humanos , Masculino , Persona de Mediana Edad , Próstata , Neoplasias de la Próstata/complicaciones , Neoplasias de la Próstata/terapia , Estudios RetrospectivosRESUMEN
INTRODUCTION: Von Willebrand Disease is a common inherited haemorrhagic disorder due to a deficiency of Von Willebrand Factor (VWF). In case of surgical procedures in patients who are not responsive or have contraindications to desmopressin, replacement therapy with VWF concentrates is indicated. Until recently, only plasma-derived VWF concentrates were available. A new recombinant VWF (rVWF) concentrate that contains no Factor VIII (FVIII) but a high amount of high molecular weight VWF multimers has been available in France since 2018. AIM: Describe real-world experience of using rVWF in surgical procedures. METHODS: Sixty-three surgeries for 55 patients were retrospectively analysed in 7 French haemostasis centres. RESULTS: During minor surgeries, the median (range) number of infusions was 1 (1-8) with a preoperative loading dose of 35 (19-56) rVWF IU/kg and a total median dose of 37.5 IU (12-288). During major surgeries, the median (range) number of infusions was only 3 (1-14) with a median preoperative loading dose of 36 IU (12-51) rVWF IU/kg, and a total median dose of 108 IU (22-340) rVWF IU/kg. The overall clinical efficacy was qualified as excellent/good in 61 of the procedures (97%), moderate in 1 (1.5%) and poor in 1 (1.5%). There was no accumulation of VWF or FVIII during postoperative monitoring. No thromboembolic events, anti-VWF antibodies or adverse events were reported. CONCLUSION: This French 'real-world' experience shows that a few infusions and low doses of rVWF provided effective prevention of bleeding in major and minor surgeries in inherited VWD, with no clinically significant safety concerns.
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Hemostáticos , Enfermedades de von Willebrand , Factor VIII/uso terapéutico , Hemostasis , Humanos , Estudios Retrospectivos , Enfermedades de von Willebrand/tratamiento farmacológico , Factor de von WillebrandRESUMEN
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.
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Angiodisplasia , Enfermedades de von Willebrand , Angiodisplasia/complicaciones , Angiodisplasia/diagnóstico , Endoscopía , Hemorragia Gastrointestinal/diagnóstico , Humanos , Pronóstico , Enfermedades de von Willebrand/complicaciones , Enfermedades de von Willebrand/diagnósticoRESUMEN
We retrospectively analysed the data files of 171 adults and 87 children/adolescents with severe haemophilia, except for 14 patients (moderate; minor) (1), to develop a global population pharmacokinetic (PK) model for eight factors VIII (FVIII) that could estimate individual PK parameters for targeting the desired level of FVIII activity (FVIII:C); and (2) to compare half-life (HL) in patients switching from a standard half-life (SHL) to an extended half-life (EHL) and evaluate the relevance of the switch. One-stage clotting assay for the measurement of FVIII activity (FVIII:C, IU/mL) was used for population PK modelling. The software, Monolix version 2019R1, was used for non-linear mixed-effects modelling. A linear two-compartment model best described FVIII:C. The estimated PK parameters (between-subject variability) were: 2640 mL (23.2%) for volume of central compartment (V1), 339 mL (46.8%) for volume of peripheral compartment (V2), 135 mL/h for Q (fixed random effect), and 204 mL/h (34.9%) for clearance (Cl). Weight, age, and categorical covariate EHL were found to influence Cl and only weight for V1. This model can be used for all of the FVIII cited in the study. Moreover, we demonstrated, in accordance with previous studies, that Elocta had longer half-life (EHL) than SHL (mean ratio: 1.48) as compared to Advate, Factane, Kogenate, Novoeight, and Refacto.
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The thrombin generation (TG) assay evaluates haemostatic balance, which is influenced by the levels of many coagulation factors and inhibitors. Our objective was to identify the determinant factors of TG in haemophilia A (HA) and haemophilia B (HB) patients and to compare them to those in healthy controls. Coagulation factor and inhibitor levels, and TG, were measured in platelet-poor plasma from 40 patients with HA, 32 patients with HB and 40 healthy subjects. Data were analysed using multiple regression models. In HA patients, factor VIII was a positive determinant of endogenous thrombin potential (ETP) and peak, whereas tissue factor pathway inhibitor (TFPI) and factor V were negative determinants of ETP and peak. In HB patients, FIX was a positive determinant of ETP and peak, FVII being a positive determinant of peak. Antithrombin and protein S (PS) were negative determinants of ETP while FX was a negative determinant of peak. Above all, in HB patients, TFPI was a negative determinant of ETP and peak. In healthy subjects, FVIII was a positive determinant of ETP and peak, whereas FX and protein S were negative determinants of these parameters. TFPI was not a negative determinant of either peak or ETP. In haemophilic patients, the determinant factors of TG are all implicated in FXa generation and inhibition, the crucial determinant factor being TFPI whatever the type of haemophilia, A or B. These findings contribute to the rationale that recently place TFPI as a target for innovative therapies of haemophilia.
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Pruebas de Coagulación Sanguínea/métodos , Hemofilia A/diagnóstico , Hemofilia B/diagnóstico , Lipoproteínas/análisis , Trombina/metabolismo , Adolescente , Adulto , Anciano , Factores de Coagulación Sanguínea/análisis , Estudios de Casos y Controles , Fibrinógeno/análisis , Hemofilia A/patología , Hemofilia B/patología , Humanos , Masculino , Persona de Mediana Edad , Índice de Severidad de la Enfermedad , Adulto JovenRESUMEN
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.
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Hemofilia A/terapia , Transición a la Atención de Adultos , Cumplimiento y Adherencia al Tratamiento/estadística & datos numéricos , Rendimiento Académico , Adolescente , Adulto , Actitud Frente a la Salud , Estudios Transversales , Relaciones Familiares , Femenino , Francia , Hemofilia A/psicología , Humanos , Masculino , Satisfacción del Paciente , Factores Protectores , Investigación Cualitativa , Calidad de Vida , Factores de Riesgo , Clase Social , Cumplimiento y Adherencia al Tratamiento/psicología , Adulto JovenRESUMEN
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.
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Inhibidores de Factor de Coagulación Sanguínea/sangre , Factor IX/administración & dosificación , Hemofilia B , Adolescente , Adulto , Factores de Edad , Niño , Preescolar , Factor IX/efectos adversos , Femenino , Estudios de Seguimiento , Francia , Hemofilia B/sangre , Hemofilia B/tratamiento farmacológico , Humanos , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Vigilancia de Productos Comercializados , Estudios ProspectivosRESUMEN
The ristocetin cofactor activity assay (VWF:RCo) is the reference method for assessing von Willebrand factor (VWF) activity but remains difficult to perform, and the coefficient of variation of the method is high (about 20-30%). This study evaluated and compared the performance for measuring the VWF activity of two newly commercialised assays [VWF:Ac Innovance (VWF:Ac) and VWF:RCo Acustar (VWF:RCo Acu)] with the reference VWF:RCo aggregation in 123 pathological plasma samples. The correlation and concordance between both new tests (VWF:RCo-Acu and VWF:Ac) and the reference VWF:RCo were good. The results of the VWF activity to VWF antigen ratio were also comparable whatever the method for the classification of VWF deficiency in all patients. Our results showed that both new tests could replace the "gold standard" VWF:RCo in aggregometry with several benefits: they are fully automated, easier and faster to perform, better adapted to emergency situations if necessary.