Factor XIII deficiency
|Factor XIII deficiency|
|Classification and external resources|
Factor XIII deficiency may occur very rarely, and can cause a severe bleeding tendency. The incidence is 1 in a million to 1 in 5 million people. Most are due to mutations in the A subunit gene (located on chromosome 6p25-p24). This mutation is inherited in an autosomal recessive fashion.
As Factor XIII is composed of two subunit protein A and B, for which the genes are located on different chromosomes, administration of recombinant A subunit improves clot stability and is becoming a therapeutic option for patients with this condition. This deficiency leads to defective cross-linking of fibrin and vulnerability to late re-bleeds when the primary hemostatic plug is overwhelmed. Bleeding tendencies similar to hemophiliacs develop such as hemarthroses and deep tissue bleeding.
Fresh frozen plasma and cryoprecipitate
Fresh frozen plasma and cryoprecipitate are the mainstay of therapy for Factor XIII deficiency, but carries risk related to transfusion.
Factor XIII concentrates
Two commercially-produced factor XIII concentrates are currently available in Europe, one is manufactured by Bio Products Laboratory (BPL) and is only available in the United Kingdom, and the other called Fibrogammin-P and is produced by Beringwerke of Germany. FXIII concentrate is only available under IND or through clinical trial in the United States.
Recombinant Factor XIII
Recombinant Factor XIII (rFXIII) is the only prospective drug alternative to receiving blood transfusions, the traditional treatment for Factor XIII deficiency. Novo Nordisk’s rFXIII is not currently a marketed drug but just recently finished phase III clinical trials in Spring 2010. Although it is a recombinant protein, rFXIII subunit A is identical in structure and function to the A subunit of factor XIII naturally produced in the body by healthy individuals. These patients need exogenous subunit A of factor XIII since they have a mutation which prevents production of the A subunit. However, since the B-subunit is located on a separate chromosome, factor XIII deficient patients actually produce the B-subunit normally. When these two subunits interact in the plasma, the enzyme is activated and can act within the clotting cascade. rFXIII acts by inhibiting fibrinolysis factors which enzymatically cleave the fibrin matrix, leading to the ultimate formation of clots.
rFXIII is synthetically bio-engineered through a yeast expression system and administered intravenously. In clinical trials, the drug was administered once every four weeks or administered on-demand in order to treat bleeding episodes. The introduction of rFXIII as a treatment for factor XIII deficiency eliminates the risk of pathogenic infection present in plasma-based treatments. rFXIII treatment would also not be dependent on blood donations consequently increasing availability and product quality. One of the biggest fears in developing rFXIII was that the body would mount an immune-response to the protein; however, several safety and pharmokinetics studies have reported no immunogenic response to rFXIII or associated yeast products.
- Lovejoy A, Reynolds T, Visich J, Butine M, Young G, Belvedere M, Blain R, Pederson S, Ishak L, Nugent D (2006). "Safety and pharmacokinetics of recombinant factor XIII-A2 administration in patients with congenital factor XIII deficiency.". Blood 108 (1): 57–62. doi:10.1182/blood-2005-02-0788. PMID 16556896.
- "Recombinant Factor XIII.". 2010.
- Muszbek, Laszlo et al. (1999). "Blood coagulation factor XIII: structure and function.". Thrombosis Research 94 94 (5): 271–305. doi:10.1016/S0049-3848(99)00023-7.
- Clinical Trials at Novo Nordisk. (2010). "Evaluation of Recombinant Factor XIII for Prevention of Bleeding in Patients with FXIII Inherited Deficiency.".