WILATE Powder and solvent for solution for injection Ref.[50681] Active ingredients: Coagulation factor VIII Von Willebrand factor

Pharmacotherapeutic group: Antihaemorrhagics: blood coagulation factors Von Willebrand factor and coagulation factor VIII in combination
ATC Code: B02BD06

Von Willebrand disease (VWD)

The VWF (from the concentrate) is a normal constituent of the human plasma and behaves in the same way as endogenous VWF.

Administration of VWF allows correction of the haemostatic abnormalities exhibited in patients who suffer from VWF deficiency (VWD) at two levels:

• VWF re-establishes platelet adhesion to the vascular sub-endothelium at the site of vascular damage (as it binds both to the vascular sub-endothelium and to the platelet membrane), providing primary haemostasis as shown by the shortening of the bleeding time. This effect occurs immediately and is known to depend to a large extent to the level of polymerisation of the protein;
• VWF produces delayed correction of the associated factor VIII deficiency. Administered intravenously, VWF binds endogenous factor VIII (which is produced normally by the patient), and by stabilising this factor, avoids its rapid degradation. Because of this, administration of pure VWF (VWF product with a low factor VIII level) restores the FVIII:C level to normal as a secondary effect after first infusion. Administration of a factor VIII-containing VWF preparation restores the FVIII:C level to normal immediately after first infusion.

In addition to its role as a factor VIII-protecting protein, VWF mediates platelet adhesion to sites of vascular injury and plays a role in platelet aggregation.

Haemophilia A

The factor VIII/von Willebrand factor complex consists of two molecules (factor VIII and von Willebrand factor) with different physiological functions. When infused into a haemophiliac patient, factor VIII binds to von Willebrand factor in the patient´s circulation. Activated factor VIII acts as a cofactor for activated factor IX, accelerating the conversion of factor X to activated factor X. Activated factor X converts prothrombin into thrombin. Thrombin then converts fibrinogen into fibrin and a clot can be formed.

Haemophilia A is a sex-linked hereditary disorder of blood coagulation due to decreased levels of FVIII:C and results in profuse bleeding into joints, muscles or internal organs, either spontaneously or as results of accidental or surgical trauma. By replacement therapy the plasma levels of factor VIII are increased, thereby enabling a temporary correction of the factor deficiency and correction of the bleeding tendencies.

Of note, annualized bleeding rate (ABR) is not comparable between different factor concentrates and between different clinical studies.

In addition to its role as a factor VIII protecting protein, von Willebrand factor mediates platelet adhesion to sites of vascular injury and plays a role in platelet aggregation.