Neutralizing antibodies (inhibitors) toward factor VIII form a severe complication in nonsevere hemophilia A, profoundly aggravating the bleeding pattern. Identification of high-risk patients is ...hampered by lack of data that take exposure days to therapeutic factor VIII concentrates into account. In the INSIGHT study, we analyzed the association between F8 mutation and inhibitor development in patients with nonsevere hemophilia A (factor VIII 2-40 IU/dL). This analysis included 1112 nonsevere hemophilia A patients from 14 centers in Europe and Australia that had genotyped at least 70% of their patients. Inhibitor risk was calculated as Kaplan-Meier incidence with cumulative number of exposure days as the time variable. During 44 800 exposure days (median, 24 exposure days per patient; interquartile range IQR, 7-90), 59 of the 1112 patients developed an inhibitor; cumulative incidence of 5.3% (95% confidence interval CI, 4.0-6.6) after a median of 28 exposure days (IQR, 12-71). The inhibitor risk at 50 exposure days was 6.7% (95% CI, 4.5-8.9) and at 100 exposure days the risk further increased to 13.3% (95% CI, 9.6-17.0). Among a total of 214 different F8 missense mutations 19 were associated with inhibitor development. These results emphasize the importance of F8 genotyping in nonsevere hemophilia A.
•The inhibitor incidence in nonsevere hemophilia A patients with certain F8 mutations approaches the inhibitor incidence in severe patients.•These findings are highly relevant for clinical practice, as they facilitate identification of high-risk patients based on F8 genotype.
Acquired hemophilia A (AHA) is caused by autoantibodies against factor VIII (FVIII). Immunosuppressive treatment (IST) results in remission of disease in 60% to 80% of patients over a period of days ...to months. IST is associated with frequent adverse events, including infections as a leading cause of death. Predictors of time to remission could help guide IST intensity but have not been established. We analyzed prognostic factors in 102 prospectively enrolled patients treated with a uniform IST protocol. Partial remission (PR; defined as no active bleeding, FVIII restored >50 IU/dL, hemostatic treatment stopped >24 hours) was achieved by 83% of patients after a median of 31 days (range 7-362). Patients with baseline FVIII <1 IU/dL achieved PR less often and later (77%, 43 days) than patients with ≥1 IU/dL (89%, 24 days). After adjustment for other baseline characteristics, low FVIII remained associated with a lower rate of PR (hazard ratio 0.52, 95% confidence interval 0.33-0.81, P < .01). In contrast, PR achieved on steroids alone within ≤21 days was more common in patients with FVIII ≥1 IU/dL and inhibitor concentration <20 BU/mL (odds ratio 11.2, P < .0001). Low FVIII was also associated with a lower rate of complete remission and decreased survival. In conclusion, presenting FVIII and inhibitor concentration are potentially useful to tailor IST in AHA.
•This study is the first to assess prognostic factors in patients with AHA treated according to a uniform immunosuppressive regimen.•Residual factor VIII activity and inhibitor concentration at baseline are potentially useful predictors of remission.
Recombinant VIII (rVIII)-SingleChain is a novel B-domain–truncated recombinant factor VIII (rFVIII), comprised of covalently bonded factor VIII (FVIII) heavy and light chains. It was designed to have ...a higher binding affinity for von Willebrand factor (VWF). This phase 1/3 study investigated the efficacy and safety of rVIII-SingleChain in the treatment of bleeding episodes, routine prophylaxis, and surgical prophylaxis. Participants were ≥12 years of age, with severe hemophilia A (endogenous FVIII <1%). The participants were allocated by the investigator to receive rVIII-SingleChain in either an on-demand or prophylaxis regimen. Of the 175 patients meeting study eligibility criteria, 173 were treated with rVIII-SingleChain, prophylactically (N = 146) or on-demand (N = 27). The total cumulative exposure was 14 306 exposure days (EDs), with 120 participants reaching ≥50 EDs and 52 participants having ≥100 EDs. Hemostatic efficacy was rated by the investigator as excellent or good in 93.8% of the 835 bleeds treated and assessed. Across all prophylaxis regimens, the median annualized spontaneous bleeding rate was 0.00 (Q1, Q3: 0.0, 2.4) and the median overall annualized bleeding rate (ABR) was 1.14 (Q1, Q3: 0.0, 4.2). Surgical hemostasis was rated as excellent/good in 100% of major surgeries by the investigator. No participant developed FVIII inhibitors. In conclusion, rVIII-SingleChain is a novel rFVIII molecule showing excellent hemostatic efficacy in surgery and in the control of bleeding events, low ABR in patients on prophylaxis, and a favorable safety profile in this large clinical study. This trial was registered at www.clinicaltrials.gov as #NCT01486927.
•rVIII-SingleChain is a novel rFVIII, designed to have high stability and high binding affinity for VWF.•In severe hemophilia A patients, rVIII-SingleChain was well tolerated and resulted in low bleeding rates, when dosed twice per week.
During factor VIII prophylaxis for severe hemophilia A, bleeding risk increases with time when factor VIII activity is below 1%. Maintaining trough activity above 1% does not protect all patients ...from bleeding. The relationship between factor VIII activity during prophylaxis and bleeding risk has not been thoroughly studied. We investigated factor VIII activity and annualized bleeding rate for spontaneous bleeds during prophylaxis. A population pharmacokinetic model derived from three clinical trials was combined with dosing data and bleed information from patient diaries. Each patients' time on prophylaxis was divided into five categories of predicted activity (0-1%, >1-5%, >5-15%, >15-50%, and >50%). Exposure time, mean factor VIII activity, and bleed number (from patient diaries) were calculated for each activity category, and annualized bleeding rates estimated using negative binomial regression and a parametric model. Relationships between these bleeding rates and factor VIII activity were evaluated by trial phase (pivotal vs. extension) and age (adults/adolescents ≥12 years vs. children 0-<12 years). In total (N=187; 815 patient-years' exposure), factor VIII activity was predicted to reach >1% for 85.64% of the time. Annualized bleeding rate decreased as factor VIII activity increased in each trial phase and age group. However, for a given activity level, bleeding rate differed substantially by trial phase, and age. This suggests that bleeding risk can change over time and is influenced by factors independent of factor VIII pharmacokinetics and trough levels. Target trough and prophylactic regimen should consider patient age, joint disease activity, and other bleeding risk determinants.
Cardiovascular disease is an emerging medical issue in patients with hemophilia (PWH) and its prevalence is increasing up to 15% in PWH in the United States. Atrial fibrillation, acute and chronic ...coronary syndromes, venous thromboembolism, and cerebral thrombosis are frequent thrombotic or prothrombotic situations, which require a careful approach to fine‐tune the delicate balance between thrombosis and hemostasis in PWH when using both procoagulant and anticoagulant treatments. Generally, PWH could be considered as being naturally anticoagulated when clotting factors are <20 IU/dL, but specific recommendations in patients with very low levels according to the different clinical situations are lacking and mainly based on the anecdotal series. For PWH with baseline clotting factor levels >20 IU/dL in need for any form of antithrombotic therapy, usually treatment without additional clotting factor prophylaxis could be used, but careful monitoring for bleeding is recommended. For antiplatelet treatment, this threshold could be lower with single‐antiplatelet agent, but again factor level should be at least 20 IU/dL for dual antiplatelet treatment. In this complex growing scenario, the European Hematology Association in collaboration with the International Society on Thrombosis and Haemostasis, the European Association for Hemophilia and Allied Disorders, the European Stroke Organization, and a representative of the European Society of Cardiology Working Group on Thrombosis has produced this current guidance document to provide clinical practice recommendations for health care providers who care for PWH.
Abstract
Background
The efficacy, safety, and immunogenicity of each of Octapharma's factor VIII (FVIII) products, Nuwiq, octanate, and wilate, have been investigated in previously untreated ...patients (PUPs) with severe hemophilia A in prospective clinical trials. The aim of the Protect-NOW study is to evaluate the effectiveness, safety, and utilization patterns of Nuwiq, octanate, and wilate in PUPs and minimally treated patients (MTPs; <5 exposure days EDs to FVIII concentrates or other blood products containing FVIII) with severe hemophilia A in a real-world setting. Real-world data provide valuable information that complement data obtained from interventional clinical trials.
Methods
Protect-NOW (ClinicalTrials.gov identifier: NCT03695978; ISRCTN identifier: 11492145) is a real-world study in PUPs and MTPs treated with either the human cell line-derived recombinant FVIII Nuwiq (simoctocog alfa) or a plasma-derived FVIII concentrate containing von Willebrand factor (octanate or wilate). It is a prospective and (partly) retrospective, observational, international, noncontrolled, noninterventional study. A total of 140 PUPs and MTPs with severe hemophilia A will be enrolled across around 50 specialized centers worldwide and followed for either 100 EDs or a maximum period of 3 years from ED1. The primary objectives are to assess effectiveness in the prevention and treatment of bleeding episodes and overall safety, including inhibitor development. The secondary objectives are to assess utilization patterns (including dosage and frequency of administration) and the effectiveness in surgical prophylaxis.
Conclusions
The Protect-NOW study will provide information on the treatment of PUPs and MTPs in routine clinical practice, which will help guide clinical decision making for treating these patients in the future.
It is an honor and a great pleasure for us to be guest editors for this special issue of
, which addresses important issues surrounding the complex of venous thromboembolism (VTE). In February 2023, ...the revised guideline on "Diagnostics and Therapy of Venous Thrombosis and Pulmonary Embolism" has been published on the website of the Association of the Scientific Medical Societies in Germany (AWMF)1. This guideline was drawn up under the leadership of the German Society of Angiology (DGA), and representatives of 17 scientific societies contributed to its content. As an S2k guideline, its recommendations are consensus based and are the result of a systematic review and evaluation of current evidence and consideration of the benefits and harms of diagnostic and therapeutic options. In this special issue, guideline authors provide a comprehensive overview of selected guideline topics which might be of clinical relevance to our readers and our community of haemostaseologists.
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