scholarly journals Gene-based FVIIa prophylaxis modulates the spontaneous bleeding phenotype of hemophilia A rats

2019 ◽  
Vol 3 (3) ◽  
pp. 301-311 ◽  
Author(s):  
Shannon M. Zintner ◽  
Juliana C. Small ◽  
Giulia Pavani ◽  
Lynn Dankner ◽  
Oscar A. Marcos-Contreras ◽  
...  
Keyword(s):  
Statistical Power ◽  
Hemophilia A ◽  
Tolerance Induction ◽  
Coagulation Factor ◽  
Factor Vii ◽  
Spontaneous Bleeding ◽  
Coagulation Factor Vii ◽  
On Demand ◽  
Activated Factor Vii

Abstract A sizable proportion of hemophilia inhibitor patients fails immune tolerance induction and requires bypass agents for long-term bleed management. Recombinant human-activated coagulation Factor VII (rhFVIIa) is an on-demand bypass hemostatic agent for bleeds in hemophilia inhibitor patients. Prophylactic use of rhFVIIa may enable sustained hemostatic management of inhibitor patients, but the critical relationship of rhFVIIa circulating levels and clinical outcome in that setting remains unclear. To address this in vivo, we used the rat hemophilia A (HA) model that exhibits spontaneous bleeds and allows longitudinal studies with sufficient statistical power. We simulated activated Factor VII (FVIIa) prophylaxis by adeno-associated virus (AAV) gene transfer of a rat FVIIa transgene. Compared with naive HA animals, rat FVIIa continuous expression affected the overall observed bleeds, which were resolved with on-demand administration of recombinant rat FVIIa. Specifically, although 91% of naive animals exhibited bleeds, this was reduced to 83% and 33% in animals expressing less than 708 ng/mL (<14 nM) and at least 708 ng/mL (≥14 nM) rat FVIIa, respectively. No bleeds occurred in animals expressing higher than 1250 ng/mL (>25 nM). Rat FVIIa expression of at least 708 ng/mL was also sufficient to normalize the blood loss after a tail vein injury. Continuous, AAV-mediated rat FVIIa transgene expression had no apparent adverse effects in the hemostatic system of HA rats. This work establishes for the first time a dose dependency and threshold of circulating FVIIa antigen levels for reduction or complete elimination of bleeds in a setting of FVIIa-based HA prophylaxis.

scholarly journals Diagnosis and Treatment of Acquired Hemophilia: One Single-Center Experience from PR. China

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 4250-4250
Author(s):  
Rong-Fu Zhou ◽  
Yueyi Xu ◽  
Wenjin Gao
Keyword(s):  
Hemophilia A ◽  
Conflicts Of Interest ◽  
Clinical Manifestations ◽  
Coagulation Factor ◽  
Factor Vii ◽  
Acquired Hemophilia A ◽  
Acquired Hemophilia ◽  
Coagulation Factor Vii ◽  
Prolonged Aptt ◽  
Inhibitor Titer

Abstract Objective: To deepen the understanding of the clinical manifestations of acquired hemophilia A for timely and correctly treatment. Methods: The clinical data of the acquired hemophilia A patients diagnosed in the hospital from Jan 2006 to Mar 2021 were retrospectively analyzed, and the relevant literature was reviewed. Results: 17 patients with acquired hemophilia A, male: female =10: 7, median age 61 years (19 to 78 years), were diagnosed and treated in the hospital with the median time from the onset to diagnosis 21 days (2 days to 6 months). Six patients had comorbidity, including hepatitis B carrying, chronic myelomonocytic leukemia, diabetes, hypertension and positive autoantibodies, pemphigoid and gastric cancer, respectively. Other 11 patients were healthy before the onset. All patients had large large ecchymosis of skin, and one case was combined with hematuria, and one case with retroperitoneal hematoma. All patients had APTT extension (45s-144.7s) and the prolonged APTT could not be corrected with normal mixed plasma with and without incubation at 37℃ for 2 hours. FVIII activity was 1% - 8.9% and inhibitor titer 2 - 128 Bu/ml. All patients with bleeding were with prothrombin complex/recombinant activated coagulation factor VII, some of them with pd-coagulation factor FVIII preparations. Inhibitors were removed with prednisone acetate (1 case) + chemotherapy (1 case), prednisone acetate / + CTX (11 cases) + chemotherapy (1 case), prednisone acetate/prednisolone + mabthera (2 cases) + CTX (1 case), respectively. The removal time of inhibitor was from 8 days to 4 years. During the treatment process, two patients developed lower extremity venous thrombosis, and one patient was complicated with lung infection. Conclusion: Patients with unexplained bleeding and prolonged APTT should be conducted normal mixed plasma correction test, coagulation factor activity and inhibitor titer examination. After correctly diagnosis, bypass agents /coagulation factor VIII preparations should be given timely for hemostasis, protocol based on glucocorticoid + CTX/mabthera to remove the inhibitor and symptomatic treatment for patients with primary comorbidity disease at the same time. Disclosures No relevant conflicts of interest to declare.

scholarly journals Successful treatment of canine hemophilia by continuous expression of canine FVIIa

Blood ◽  
2009 ◽  
Vol 113 (16) ◽  
pp. 3682-3689 ◽  
Author(s):  
Paris Margaritis ◽  
Elise Roy ◽  
Majed N. Aljamali ◽  
Harre D. Downey ◽  
Urs Giger ◽  
...  
Keyword(s):  
Gene Transfer ◽  
Hemophilia A ◽  
Viral Vector ◽  
Canine Model ◽  
Factor Vii ◽  
Large Animal Model ◽  
Large Animal ◽  
Spontaneous Bleeding ◽  
Human Factor Viii

Abstract Continuous expression of activated factor VII (FVIIa) via gene transfer is a potential therapeutic approach for hemophilia patients with or without inhibitory antibodies to human factor VIII (FVIII) or IX (FIX). Here, we investigate whether gene transfer of an engineered canine FVIIa (cFVIIa) transgene can affect hemostasis in a canine model of hemophilia, a good predictor of efficacy of hemophilia treatments. Purified recombinant cFVIIa exhibited 12-fold higher tissue factor–dependent activity than purified recombinant zymogen cFVII. Subsequently, we generated a serotype 8 recombinant adeno-associated viral vector expressing cFVIIa from a liver-specific promoter. Vector delivery via the portal vein in hemophilia A and B dogs was well tolerated, and long-term expression of cFVIIa resulted in a shortening of the prothrombin time, partial correction of the whole blood clotting time and thromboelastography parameters, and a complete absence of spontaneous bleeding episodes. No evidence of hepatotoxicity, thrombotic complications, or inhibitory immune response was found. These data provide the first evidence for in vivo efficacy and safety of continuously expressed FVIIa as a FVIII/FIX-bypassing agent in a large animal model of hemophilia, avoiding the risk of inhibitor formation associated with bolus FVIII or FIX infusion.

Elevated Levels of Factor VII Activity in the Postprandial State: Effect of the Factor VII Arg-GIn Polymorphism

1994 ◽  
Vol 72 (05) ◽  
pp. 734-739 ◽  
Author(s):  
Angela Silveira ◽  
Fiona Green ◽  
Fredrik Karpe ◽  
Margareta Blombäck ◽  
Steve Humphries ◽  
...  
Keyword(s):  
Coagulation Factor ◽  
Plasma Lipoproteins ◽  
Factor Vii ◽  
Percentage Increase ◽  
Fat Intake ◽  
Postprandial Lipaemia ◽  
Coagulation Factor Vii ◽  
Postprandial State ◽  
Activated Factor Vii ◽  
Before And After

SummaryA genetic polymorphism (Arg/Gln353) of coagulation factor VII was recently identified and shown to be associated with differences in basal factor VII coagulant activity. Postprandial lipaemia seems to exert an acute but evanescent effect on the activity of factor VII, and the influence of the Arg/Gln353 polymorphism on factor VII activation during postprandial lipaemia was therefore studied in male post-infarction patients [age 48.8 ± 3.3 years (mean ± SD)] with Arg/Arg (n = 23) and Arg/Gln (n = 8) genotypes. Factor VII antigen (VIlag) and activity along with plasma lipoproteins were determined before and after intake of a mixed meal-type of oral fat load. Patients with the Arg/Gln genotype had basal VIlag and activated factor VII (Vila) levels 75% and 48%, respectively, of those of patients homozygous for the Arg allele. In absolute terms, Vila increased more in homozygotes for the Arg allele (AO-6 h Vila 1.76 ± 1.48 ng/ml) than in heterozygotes (0.60 ± 0.27 ng/ml) in response to fat intake, but the percentage increase in Vila molecules did not differ significantly between subjects with Arg/Arg and Arg/Gln genotypes (37 ± 32% versus 27 ± 15%). This suggests that the influence of the Arg/Gln polymorphism on factor VII activity is mainly accounted for by differences in the basal factor VII protein level between genotypes. Since most of our lives are spent in the postprandial state, possession of the factor VII-Gln353 allele is likely to confer protection against coronary heart disease by reducing the amount of Vila produced in response to fat intake.

scholarly journals Treatment patterns and bleeding outcomes in persons with severe hemophilia A and B in a real-world setting

2020 ◽  
Author(s):  
Cihan Ay ◽  
Leonard Perschy ◽  
Judit Rejtö ◽  
Alexandra Kaider ◽  
Ingrid Pabinger
Keyword(s):  
Real World ◽  
Hemophilia A ◽  
Coagulation Factor ◽  
Treatment Patterns ◽  
Severe Hemophilia ◽  
Current Standard ◽  
Spontaneous Bleeding ◽  
Specific Patient ◽  
Therapy Regimen ◽  
On Demand

Abstract The current standard of care treatment for severe hemophilia A and B (SHA and SHB) is the prophylactic intravenous replacement of coagulation factor VIII or IX (FVIII/FIX) to prevent spontaneous bleeding. Persons with hemophilia without prophylactic treatment receive therapy in case of bleeding, i.e., on demand. To assess treatment patterns, utilization of products, and bleeding outcomes in a real-world cohort of persons with SHA and SHB, defined as FVIII or FIX activity < 1%, data was retrospectively collected from hemophilia-specific patient diaries used for home treatment, medical records, and entries into the Austrian Hemophilia Registry from the year 2012 to 2017. Fifty-three male persons with SHA (n = 47) and SHB (n = 6) were included; 26 with SHA and 5 with SHB were on prophylaxis, 8 and 1 switched therapy regimen, and 13 and 0 received on-demand therapy. Persons on prophylaxis used a mean factor FVIII or FIX dose of 71.7 and 40.1 IU/kg/week. Median (IQR) annualized bleeding rates (ABR) in SHA were 28.0 (23.4–31.3) in the on-demand, 4.9 (1.6–13.5) in the prophylaxis group, and 3.0 (2.0–6.8) in the prophylactic group of SHB. Three persons with SHA had zero bleeds during the observation period. On-demand therapy and hepatitis B and C were associated with higher ABR but not age, weight, and HIV positivity. Bleeding rates and the proportion of on-demand therapy in persons with hemophilia were high in our real-world cohort. Further improvement is needed, which might be facilitated with the advent of factor products with extended half-life or non-factor therapies.

scholarly journals Acquired Hemophilia A Presenting as Massive Postoperative Bleeding in a Patient with Oral Squamous Cell Carcinoma

2020 ◽  
Vol 2020 ◽  
pp. 1-5
Author(s):  
Susumu Oba ◽  
Mitsuhiko Nakahira ◽  
Yasunao Kogashiwa ◽  
Yasuhiro Ebihara ◽  
Masashi Sugasawa
Keyword(s):  
Hemophilia A ◽  
Postoperative Bleeding ◽  
Laboratory Data ◽  
Tumor Resection ◽  
Coagulation Factor ◽  
Factor Vii ◽  
Acquired Hemophilia A ◽  
Acquired Hemophilia ◽  
Spontaneous Bleeding ◽  
Recombinant Activated Factor Vii

Acquired hemophilia A (AHA) is an extremely rare and serious bleeding disorder caused by autoantibodies against coagulation factor VIII (FVIII). Approximately, 10% of patients with AHA have an underlying malignancy. We report on a 46-year-old man with AHA and advanced oral cancer who presented with massive bleeding after surgery. Preoperative blood coagulation tests showed no abnormalities. He underwent radical tumor resection followed by reconstruction using a free rectus abdominal musculocutaneous flap. Massive subcutaneous hemorrhage developed in his neck and abdomen on the first postoperative day. The hemorrhage remained uncontrolled, despite embolization of the responsible vessels. Subsequent laboratory data showed prolonged activated partial thromboplastin time and decreased FVIII levels. On the basis of his clinical course and the presence of the FVIII inhibitor, we speculated that the patient suffered from AHA. We administered recombinant activated factor VII and prednisolone, after which the spontaneous bleeding stopped and the subcutaneous hemorrhage resolved. A review of the literature identified only three previous documented cases of AHA associated with head and neck cancer. This case indicates that AHA should not be ruled out in patients with uncontrolled postoperative bleeding, while attempting to ensure bleeding control and preventing potentially catastrophic fatal consequences.

The Clotting Trigger Is an Important Determinant for the Coagulation Pathway In Vivo or In Vitro—Inference from Data Review

2020 ◽  
Author(s):  
Shu He ◽  
Honglie Cao ◽  
Charlotte Thålin ◽  
Jan Svensson ◽  
Margareta Blombäck ◽  
...  
Keyword(s):  
Coagulation Factor ◽  
Coagulation Cascade ◽  
Factor Vii ◽  
Enzymatic Reactions ◽  
Rotational Thromboelastometry ◽  
Coagulation Factor Vii ◽  
Charged Surfaces ◽  
Coagulation Pathway

AbstractBlood coagulation comprises a series of enzymatic reactions leading to thrombin generation and fibrin formation. This process is commonly illustrated in a waterfall-like manner, referred to as the coagulation cascade. In vivo, this “cascade” is initiated through the tissue factor (TF) pathway, once subendothelial TF is exposed and bound to coagulation factor VII (FVII) in blood. In vitro, a diminutive concentration of recombinant TF (rTF) is used as a clotting trigger in various global hemostasis assays such as the calibrated automated thrombogram, methods that assess fibrin turbidity and fibrin viscoelasticity tests such as rotational thromboelastometry. These assays aim to mimic in vivo global coagulation, and are useful in assessing hyper-/hypocoagulable disorders or monitoring therapies with hemostatic agents. An excess of rTF, a sufficient amount of negatively charged surfaces, various concentrations of exogenous thrombin, recombinant activated FVII, or recombinant activated FIXa are also used to initiate activation of specific sub-processes of the coagulation cascade in vitro. These approaches offer important information on certain specific coagulation pathways, while alterations in pro-/anticoagulants not participating in these pathways remain undetectable by these methods. Reviewing available data, we sought to enhance our knowledge of how choice of clotting trigger affects the outcome of hemostasis assays, and address the call for further investigations on this topic.

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