Overall haemostatic potential can be used for estimation of thrombin-activatable fibrinolysis inhibitor-dependent fibrinolysis in vivo and for possible follow-up of recombinant factor VIIa treatment in patients with inhibitors to factor VIII

Haemophilia ◽  
2002 ◽  
Vol 8 (6) ◽  
pp. 781-786 ◽  
Author(s):  
J. P. Antovic ◽  
A. Antovic ◽  
S He ◽  
L. Tengborn ◽  
M. Blomback
Keyword(s):  
Factor Viii ◽  
Recombinant Factor Viia ◽  
Factor Viia ◽  
Thrombin Activatable Fibrinolysis Inhibitor ◽  
Fibrinolysis Inhibitor

Risk of Bleeding and Inhibitor Development After Circumcision in Minimally Treated Severe Hemophilia A Patients: A One Year Prospective Study,

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 4653-4653
Author(s):  
Mohsen Saleh Elalfy ◽  
Nancy Samir Elbarbary ◽  
Mohamed Soliman Eldebeiky
Keyword(s):  
Single Dose ◽  
Factor Viii ◽  
Hemophilia A ◽  
Recombinant Factor Viia ◽  
Factor Viia ◽  
High Titer ◽  
Severe Hemophilia ◽  
Inhibitor Development ◽  
Factor Concentrate

Abstract Abstract 4653 Background Circumcision is a cultural practice for males in the Middle-East during first weeks of life. All parents of hemophilics are eager to do circumcision to their sibs, however, it may carry a risk for development of factor VIII inhibitors as well as risk of excessive bleeding. Objective To evaluate post-circumcision bleeding and assess incidence and time of inhibitor development over 12 months follow-up period of minimally treated severe hemophilia A patients. Patients and methods This prospective analysis has been conducted on eighteen minimally treated patients with severe hemophilia A (age range 8–36 months) with a median age of 18 months, who underwent circumcision during 2009 and twenty four age matched non circumcised patients minimally treated severe hemophilia A. Both groups were followed up for12 months from study entry and all were treated on demand therapy with a single plasma-derived factor VIII product. Hemophilic patients who underwent circumcision were inhibitor negative except two with low- titer inhibitor(3.3 and 4.4 BU/ml) respectively. One hour before the operation, intravenous tranexamic acid (25 mg/ kg) and first dose of factor concentrate (25 unit / Kg) were given to the patients. After reaching a trough plasma factor level more than 90%, patients underwent circumcision using general anesthesia and same surgical technique for all. Bolus injections of factor VIII concentrate were repeated in a dose of (25 units / Kg ) twenty four hours after operation. However, the two patients with inhibitors were given factor VIII concentrate in a dose of (50 units /Kg) with an extra dose at forty-eight hours. Another dose of factor concentrate (25 units/ Kg) was given just before removal of gauze dressing at 5th −7th day post operative. Follow up for inhibitor development was assessed every 8 exposure days (EDs) for 12 months or 100 EDs whichever comes first. Results: Of the eighteen patients enrolled, only one of the 2 patients with low- titer inhibitor had postoperative bleeding at day 5 and 7 respectively. First attack responded to a single dose of factor administration (50 units/Kg), whereas haemostasis was achieved in the second episode after a single dose of Recombinant Factor VIIa (90 microgram/kg) and applying absorbable haemostatic agent (gelatin sponge) and binding. None of the other patients had any bleeding or infection at site of surgery. High -titer inhibitors developed in three patients (16.6 % ) during the follow-up; after 8, 16 and 40 EDs respectively in contrast to four patients (16.6 %) developed high titer inhibitor in the non circumcised group; after a median of 16 exposure days (range 8– 60 EDs). Conclusion: Our study has shown that bleeding following circumcision was absent except in low- titer inhibitor patient necessitating administration of Recombinant Factor VIIa. Moreover, circumcision was not a risk for development of inhibitor where the incidence of high- titer inhibitors during12 months follow up was low in this cohort of minimally treated patients and comparable to non circumcised group. Disclosures: No relevant conflicts of interest to declare.

Improved hemostasis with superactive analogs of factor VIIa in a mouse model of hemophilia A

Blood ◽  
2003 ◽  
Vol 102 (10) ◽  
pp. 3615-3620 ◽  
Author(s):  
Mikael Tranholm ◽  
Kim Kristensen ◽  
Annemarie T. Kristensen ◽  
Charles Pyke ◽  
Rasmus Røjkjær ◽  
...  
Keyword(s):  
Blood Loss ◽  
Bleeding Time ◽  
Hemophilia A ◽  
Recombinant Factor Viia ◽  
Factor Viia ◽  
Intrinsic Activity ◽  
Hemostatic Effect ◽  
Therapeutic Doses ◽  
Hemostatic Effects

AbstractIt is currently debated whether the mechanism of action of therapeutic doses of recombinant factor VIIa (rFVIIa, Novo-Seven) relies on the tissue factor (TF)-independent activity of the enzyme. The present study was conducted to investigate the in vivo hemostatic effects of rFVIIa and 3 analogs thereof with superior intrinsic activity (FVIIaIIa, K337A-FVIIaIia, and M298Q-FVIIa) in mice with antibody-induced hemophilia A. A highly significant dose response was observed for the bleeding time and blood loss for each of the rFVIIa variants. The bleeding time and blood loss were normalized after administration of 10 mg/kg rFVIIa, 3 mg/kg K337A-FVIIaIia, and 3 mg/kg M298Q-FVIIa, indicating a potency of these FVIIa analogs 3-4 times above that of rFVIIa in FVIII-depleted mice. The different in vivo potencies of the various forms of FVIIa could not be explained by the pharmacokinetics. Histopathological evaluation of kidneys revealed no signs of treatment-related pathological changes even after treatment with the superactive variants. The fact that FVIIa analogs with enhanced intrinsic activity are more efficacious in the murine hemophilia A model strongly suggests that the TF-independent procoagulant activity of FVIIa contributes to its clinical hemostatic effect. (Blood. 2003; 102:3615-3620)

Evaluation of the profibrinolytic properties of an anti-TAFI monoclonal antibody in a mouse thromboembolism model

Blood ◽  
2011 ◽  
Vol 117 (17) ◽  
pp. 4615-4622 ◽  
Author(s):  
Ellen Vercauteren ◽  
Jan Emmerechts ◽  
Miet Peeters ◽  
Marc F. Hoylaerts ◽  
Paul J. Declerck ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Clot Lysis ◽  
Fibrin Deposition ◽  
Thrombin Activatable Fibrinolysis Inhibitor ◽  
First Report ◽  
Fibrinolysis Inhibitor ◽  
Thrombotic Diseases

Abstract The enhancement of fibrinolysis constitutes a promising approach to treat thrombotic diseases. Activated thrombin activatable fibrinolysis inhibitor (TAFIa) attenuates fibrinolysis and is an attractive target to develop profibrinolytic drugs. TAFI can be activated by thrombin, thrombin/thrombomodulin, or plasmin, but the in vivo physiologic TAFI activator(s) are unknown. Here, we generated and characterized MA-TCK26D6, a monoclonal antibody raised against human TAFI, and examined its profibrinolytic properties in vitro and in vivo. In vitro, MA-TCK26D6 showed a strong profibrinolytic effect caused by inhibition of the plasmin-mediated TAFI activation. In vivo, MA-TCK26D6 significantly decreased fibrin deposition in the lungs of thromboembolism-induced mice. Moreover, in the presence of MA-TCK26D6, plasmin-α2-antiplasmin complexes in plasma of thromboembolism-induced mice were significantly increased compared with a control antibody, indicative of an acceleration of fibrinolysis through MA-TCK26D6. In this study, we show that plasmin is an important TAFI activator that hampers in vitro clot lysis. Furthermore, this is the first report on an anti-TAFI monoclonal antibody that demonstrates a strong profibrinolytic effect in a mouse thromboembolism model.

Sign in / Sign up

Export Citation Format

Share Document