The FDA ( Food and Drug Administration ) has approved Tretten, coagulation Factor XIII A-subunit ( recombinant ), the first recombinant product for use in the routine prevention of bleeding in adults and children who have a rare clotting disorder, known as congenital Factor XIII A-subunit deficiency.

Congenital Factor XIII deficiency is an extremely rare genetic disorder. Patients with this deficiency do not make enough Factor XIII, a protein that circulates in the blood and is important for normal clotting. Factor XIII is composed of two subunits, A and B. Factor XIII deficiency is usually caused by a deficiency of the A-subunit.

The approval of Tretten provides another therapeutic option for the prevention of bleeding in patients with Factor XIII A-subunit deficiency; without treatment, people with this rare condition are at risk for serious and life-threatening bleeding.

Tretten is a recombinant analogue of the human Factor XIII A-subunit that is produced in yeast cells and then further purified. It is a sterile freeze-dried-powder to be reconstituted with diluent and injected intravenously. Tretten can be administered by a physician or be self-administered.

The effectiveness of Tretten was studied in 77 patients with congenital Factor XIII A-subunit deficiency. Tretten was effective in preventing bleeding in 90% of the patients when given monthly.
Some of the side effects reported in this study were headache, pain in the extremities and pain at injection site. No individual in the trial developed abnormal clots.

Tretten received orphan-drug designation for this use by the FDA because it is intended for treatment of a rare disease or condition. ( Xagena )
Source: FDA, 2013

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