The device sits inside the body and activates inert blood-clotting factors which are already present in the patient's blood. He said trials in humans were planned but could not say when they would begin. He said the implant had the potential to overcome several problems which plague existing treatments for haemophilia.
Usual treatments involve replacing the missing factors by transfusion.
This often requires several sessions a week and exposes the patients to the risk of other blood-borne diseases, tragically illustrated in the 1980s when many haemophiliacs contracted the HIV virus and hepatitis. Even if the clotting factors are synthetically produced, avoiding the risk of disease, the immune systems of many patients start to reject the foreign material after a while. The new implant avoids all these problems by using a factor which is already present in the patient's blood. Factor VII is inactive and unable to help clot blood but when it seeps through the tiny pores of the implant it encounters an enzyme which activates it - factor XIIa. The active factor VII then seeps out and helps compensate for the missing blood clotting factors.