Factor VIIa in the treatment of haemophilia.
Recombinant FVIIa is being developed for treatment of haemophiliacs with antibodies against FVIII/FIX. rFVIIa was shown to be haemostatically active in haemophilia A and B dogs as well as in 20 haemophilia patients (one haemophilia B and 19 haemophilia A patients). Thirteen patients were treated for life-threatening bleedings and nine at surgery (dose: 60-90 micrograms/kg q 3-4 h). One patient underwent synovectomy in a knee joint under the cover of rFVIIa as the sole coagulation factor without any problems. One patient with FXI deficiency was successfully treated at an orchidectomy. The haemophilia B patient was treated in association with a compartment syndrome (surgical fasciotomy) with a complete haemostasis. He later uneventfully underwent skin grafting. Two CNS bleeds, a severe mouth bleed were treated as well as an extensive nasopharyngeal bleed in a patient with an acquired inhibitor against FVIII. Shortening of the prothrombin time as well as of the APTT was seen. No side-effects were observed. It is speculated whether FVIIa in complex with not only tissue factor but also phospholipids exposed at the site of injured cells directly activates FXa and thereby the final common pathway of the coagulation cascade.