N8‐GP (turoctocog alfa pegol; Esperoct) is a glycoPEGylated human recombinant factor VIII (FVIII).
Pathfinder8 (NCT01480180) was a phase 3, multinational, open‐label, nonrandomized trial to ...investigate the long‐term safety and efficacy of N8‐GP in people of all ages with severe hemophilia A previously treated with N8‐GP.
Patients were recruited from the completed phase 3 pathfinder2 and pathfinder5 trials to receive intravenous N8‐GP prophylaxis for up to 104 weeks, administered every 7 days, twice weekly, or three times weekly. Primary and secondary end points were the number of adverse events (AEs) reported and efficacy of treatment, respectively.
Overall, 160 patients were exposed to N8‐GP for a mean of 179 exposure days and 681 calendar days (≈1.9 years) per patient. In total, 119 patients experienced 510 AEs, corresponding to a rate of 1.71 AEs per patient‐year of exposure; 97.5% of AEs were mild or moderate in severity, and no AEs led to withdrawal. No patients developed FVIII inhibitors during the trial. The Poisson estimate of mean annualized bleeding rate for all bleeds (excluding surgery) and across all regimens was 1.10 (median, 0.00), and for spontaneous bleeds was 0.61 (median, 0.00). Most (55.6%) patients experienced no bleeds that required FVIII treatment (excluding perioperative bleeds). The estimated hemostatic success rate for the treatment of 322 bleeding episodes (excluding surgery) was 95.8%, including missing values as failure.
Long‐term prophylactic use of N8‐GP appeared safe and efficacious across all age groups in people with severe hemophilia A previously treated with N8‐GP.
Treatment and prevention of bleeding episodes in patients with severe haemophilia A require frequent intravenous injection of factor VIII. Inhibitory antibodies against factor VIII occur in ...approximately 30 % of these patients during the first exposure days and immune tolerance induction to eradicate the inhibitor is challenging. Prevention of bleeds in patients with haemophilia A and inhibitors is less effective and there is ongoing research for alternative treatment options. A promising approach in 2016 is the development of emicizumab (ACE910), a bi-specific IgG antibody to factor IXa and factor X, that mimics the cofactor function of factor VIII. Due to the different structure of this antibody it cannot be neutralized by factor VIII inhibitors and has the possibility to achieve haemostasis in patients with severe haemophilia A with and without inhibitors. First studies in healthy volunteers and in patients showed a shortened activated partial thromboplastin time and increased peak height of thrombin generation in a dose-dependent manner. The half-life of the drug was 4 to 5 weeks. There were no clinical signs of thrombosis and no laboratory abnormalities indicating hypercoagulability. In a first study with 18 patients with severe haemophilia A with and without inhibitors a remarkable reduction in the annualised bleeding rate occurred. Safety of the drug has to be proven in ongoing research. Mimicking the cofactor activity of factor VIII by a bispecific antibody for the treatment of severe haemophilia A is so far safe and seems to be effective and is one highlight in haemostasis 2016.
The carboxyl-terminal domains of von Willebrand factor, D4-CK, are cysteine-rich implying that they are structurally important. In this study we characterized the impact of five cysteine missense ...mutations residing in D4-CK domains on the conformation and biosynthesis of von Willebrand factor. These variants were identified as heterozygous in type 1 (p.Cys2619Tyr and p.Cys2676Phe), type 2A (p.Cys2085Tyr and p.Cys2327Trp) and as compound heterozygous in type 3 (p.Cys2283Arg) von Willebrand disease. Transient expression of human cell lines with wild-type or mutant von Willebrand factor constructs was performed. The mutated and wild-type recombinant von Willebrand factors were quantitatively and qualitatively assessed and compared. Storage of von Willebrand factor in pseudo-Weibel-Palade bodies was studied with confocal microscopy. The structural impact of the mutations was analyzed by homology modeling. Homozygous expressions showed that these mutations caused defects in multimerization, elongation of pseudo-Weibel-Palade bodies and secretion of von Willebrand factor. Co-expressions of wild-type von Willebrand factor and p.Cys2085Tyr, p.Cys2327Trp and p.Cys2283Arg demonstrated defective multimer assembly, suggesting a new pathological mechanism for dominant type 2A von Willebrand disease due to mutations in D4 and B domains. Structural analysis revealed that mutations p.Cys2283Arg, p.Cys2619Tyr and p.Cys2676Phe disrupted intra-domain disulfide bonds, whereas p.Cys2327Trp might affect an inter-domain disulfide bond. The p.Cys2327Trp variant is distinguished from the other mutants by an electrophoretic mobility shift of the multimer bands. The results highlight the importance of cysteine residues within the carboxyl-terminal of von Willebrand factor on structural conformation of the protein and consequently multimerization, storage, and secretion of von Willebrand factor.
Abstract
The novel coronavirus, SARS-CoV-2, is causing a global pandemic of life-threatening multiorgan disease, called COVID-19. Accumulating evidence indicates that patients with COVID-19 are at ...significant risk of thromboembolic complications, mainly affecting the venous, but also the arterial vascular system. While the risk of venous thromboembolism (VTE) appears to be higher in patients requiring intensive care unit support compared to those admitted to general wards, recent autopsy findings and data on the timing of VTE diagnosis relative to hospitalization clearly suggest that thromboembolic events also contribute to morbidity and mortality in the ambulatory setting. In addition to a severe hypercoagulable state caused by systemic inflammation and viral endotheliitis, some patients with advanced COVID-19 may develop a coagulopathy, which meets established laboratory criteria for disseminated intravascular coagulation, but is not typically associated with relevant bleeding. Similar to other medical societies, the Society of Thrombosis and Haemostasis Research has issued empirical recommendations on initiation, dosing, and duration of pharmacological VTE prophylaxis in COVID-19 patients.
Simoctocog alfa (human-cl rhFVIII, Nuwiq®) is a 4th generation recombinant FVIII (rFVIII), without chemical modification or fusion with any other protein/fragment. Nuwiq® is produced in a human ...embryonic kidney cell line (HEK293F), which ensures human-specific post-translational protein processing. Nuwiq® was evaluated in seven prospective clinical studies in 201 adult and pediatric previously treated patients (PTPs) with severe hemophilia A. The NuProtect study in 110 previously untreated patients (PUPs) is ongoing. The mean half-life of Nuwiq® was 15.1–17.1 h in PTP studies with adults and adolescents, and 12.5 h in children aged 2–12 years. Clinical trials in PTPs demonstrated the efficacy and safety of Nuwiq® in the prevention and treatment of bleeds and as surgical prophylaxis. In the NuPreviq study of pharmacokinetic (PK)-guided personalized prophylaxis in 66 adult PTPs, 83% of patients had no spontaneous bleeds during 6 months of personalized prophylaxis and 57% were treated ⩽2 per week. No FVIII inhibitors were detected in PTPs after treatment with 43,267 injections and >80 million IU of Nuwiq®. Interim data for 66 PUPs with ⩾20 exposure days to Nuwiq® in NuProtect demonstrated a low cumulative high-titer inhibitor rate of 12.8% actual incidence 12.1% (8/66) and convincing efficacy and safety.
Gene therapy for hemophilia B aims to ameliorate bleeding risk and provide endogenous factor IX (FIX) activity/synthesis through a single treatment, eliminating the requirement for FIX concentrate. ...AMT-060 combines an adeno-associated virus-5 (AAV5) vector with a liver-specific promoter driving expression of a codon-optimized wild-type human FIX gene. This multinational, open-label study included 10 adults with hemophilia B (FIX ≤2% of normal) and severe-bleeding phenotype. No participants tested positive for AAV5-neutralizing antibodies using a green-fluorescent protein-based assay, and all 10 were enrolled. A single dose of 5 × 1012 or 2 × 1013 genome copies of AMT-060/kilogram was administered to 5 participants each. In the low-dose cohort, mean endogenous FIX activity increased to 4.4 IU/dL. Annualized FIX use was reduced by 81%, and mean annualized spontaneous bleeding rate (ASBR) decreased from 9.8% to 4.6% (53%). In the higher-dose cohort, mean FIX activity increased to 6.9 IU/dL. Annualized FIX use decreased by 73%, and mean ASBR declined from 3.0 to 0.9 (70%). There was no reduction in traumatic bleeds. FIX activity was stable in both cohorts, and 8 of 9 participants receiving FIX at study entry stopped prophylaxis. Limited, asymptomatic, and transient alanine aminotransferase elevations in the low-dose (n = 1) and higher-dose (n = 2) cohorts were treated with prednisolone. No decrease in FIX activity or capsid-specific T-cell responses were detected during transaminase elevations. A single infusion of AMT-060 had a positive safety profile and resulted in stable and clinically important increases in FIX activity, a marked reduction in spontaneous bleeds and FIX concentrate use, without detectable cellular immune responses against capsids. This trial was registered at www.clinicaltrials.gov as #NCT02396342; EudraCT #2013-005579-42.
•AAV5 liver-directed wild-type hFIX gene transfer was well tolerated and clinically effective in severe and moderate-severe hemophilia B.•No cellular immune responses to the AAV5 vector were detected, and FIX expression levels were stable for the entire observation period.
An AAV5 vector containing the factor IX Padua allele was administered to 54 men with hemophilia B. Factor IX expression increased to approximately 39% of normal, and the annualized bleeding rate was ...decreased to 1.5.
The phase ½ hemophilia B clinical trial (AMT-060) demonstrated stable endogenous FIX levels after 3.5 years (mean FIX activity between 5.1% and 7.5%) with continued reductions in annualized bleeds to ...near zero with the higher dose, and a 78-96% reduction by year in exogenous FIX use.
The views of all the three participants from Germany participating in the AMT-060 study have been investigated about their experiences with conventional and gene therapy and the effects of the forms of therapy on everyday life.
The patients (aged 33-35 years) performed regular prophylactic replacement with factor IX concentrate prior to the gene therapy, reported 0-7 bleeds in the year prior to the treatment, with Hemophilia Joint Health Scores of 0-8. Following topics have been investigated "dealing with illness", "participation in studies", "perception of conventional therapy", "perception of gene therapy", "significance of participation in gene therapy studies", "therapy of haemophilia after the end of the study".
All three participants have started to become more active and do more sports. However, they expressed anxiety about not knowing how long the effect would last and they felt that psychological support would be needed if the factor IX level fell back in the future. No patient expressed concern about any long-term potential negative consequences of gene therapy.
Gene therapy has the potential to change the life of patients with haemophilia not only by the reduction of bleeding events but also by the increase of active and sportive activities.
Background: Arthropathy caused by repeated joint bleeding is a major complication in patients with severe hemophilia A and is associated with long-term morbidity. Factor VIII (FVIII) prophylaxis has ...proven benefits for prevention of bleeding, including joint bleeding, in these patients. Alongside preservation of joint health, FVIII prophylaxis may preserve bone mineral density (BMD) and reduce the risk of fractures. Emicizumab is a bi-specific monoclonal antibody with no structural homology to FVIII and is approved for prophylaxis in hemophilia A patients. However, data on the long-term impact of emicizumab on joint and bone health are limited. Aims: To assess the impact of long-term prophylaxis with simoctocog alfa (Nuwiq ®; a fourth generation recombinant FVIII) versus emicizumab on joint and bone health in people with hemophilia A. Methods: PROVE is a multinational, prospective, two-arm, low-interventional study that will collect clinical data on joint and bone health in patients receiving prophylaxis with simoctocog alfa or emicizumab in routine clinical practice. Approximately 200 male participants (100 in each treatment arm) at least 12 years of age with severe hemophilia A (FVIII activity FVIII:C <1%) will be enrolled. Written, informed consent will be obtained from each patient or their legal representative. The primary objective of the study is to evaluate the long-term effect of simoctocog alfa versus emicizumab on joint health as measured by magnetic resonance imaging (MRI). The primary endpoint will be a between-group comparison of the change in total score on the extended MRI (eMRI) scale (Table 1). Secondary and exploratory endpoints include the impact of simoctocog alfa vs emicizumab on bleeding rates, joint and bone health, physical activity, quality of life and safety (Table 1). Study treatments will be defined by the treating physician prior to inclusion of a patient into the study. Patients will not be randomized to the treatment groups but will continue with their current prophylactic regimen (simoctocog alfa or emicizumab). Patients will be provided with an electronic diary (eDiary) in which to record study related data, including treatment-related data, bleeding event details, fracture details, concomitant medications and adverse drug reactions. Each patient will be followed for up to 4 years. An interim analysis is planned after 2 years. Conclusion: ThePROVE study aims to generate real-world data on the long-term effects of prophylaxis with simoctocog alfa or emicizumab on joint and bone health in hemophilia A.
Acquired hemophilia A (AHA) is due to autoantibodies against coagulation factor VIII (FVIII) and most often presents with unexpected bleeding. In contrast to congenital hemophilia, the patient's ...residual FVIII activity does not seem to correlate with the risk of bleeding as suggested from previous studies. Risk factors for bleeding have not been described. We used data from the prospective GTH-AH 01/2010 study to assess the risk of bleeding and the efficacy of hemostatic therapy. FVIII activity was measured at baseline and weekly thereafter. Bleeding events were assessed by treating physicians. A total of 289 bleeds were recorded in 102 patients. There were 141 new bleeds observed starting after day 1 in 59% of the patients, with a mean rate of 0.13 bleed per patient-week in weeks 1 to 12, or 0.27 bleed per patient-week before achieving partial remission. Weekly measured FVIII activity was significantly associated with the bleeding rate, but only achieving FVIII activity ≥50% abolished the risk of bleeding. A good World Health Organization performance status assessed at baseline (score 0 vs higher) was associated with a lower bleeding rate. Hemostatic treatment was reportedly effective in 96% of bleeds. Thus, the risk of new bleeds after a first diagnosis of AHA remains high until partial remission is achieved, and weekly measured FVIII activity may aid in assessing the individual risk of bleeding. These results will help to define future strategies for prophylaxis of bleeding in AHA.
•Patients with AHA have a high risk of recurrent bleeding until they achieve partial remission of their disease.•Residual FVIII activity and clinical performance status are associated with recurrent bleeding.
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