Summary
Factor XI deficiency is an uncommon bleeding disorder usually manifested by excessive
bleeding after surgery or trauma. Until recently the only effective therapy has been
fresh-frozen plasma (FFP) infusion. We describe the efficacy and safety of a new factor
XI concentrate produced from human donor plasma by a modification of the method used
for antithrombin III concentrate. The mean recovery of factor XI in the circulation
measured on 62 occasions was approximately 91% of the injected dose, and the mean
half-disappearance-time was 52 h. The concentrate was used for 31 invasive procedures
in 30 patients, including 16 patients who had a definite bleeding tendency on previous
occasions, with normal haemostasis being achieved in all but 1. Only 1 patient (previously
experiencing allergy to FFP) experienced adverse effects during infusion. Monitoring
of liver function tests and viral antibody status in suitable patients has shown no
evidence of transmission of hepatitis viruses, HIV-1 or parvovirus B19.
We conclude that this concentrate provides effective treatment for patients with factor
XI deficiency. Preliminary results suggest safety from virus transmission, but this
needs to be established in further studies of previously untreated patients.
