Experiences in the prevention of arthropathy in haemophila patients with inhibitors

Haemophilia patients with inhibitor have a higher level of arthropathy and more severe joint morbidity than patients without inhibitors. In recent years, interest has grown in the possibility that bypassing agent regimens could prevent bleeding and, consequently, arthropathy in inhibitor patients. Nevertheless, doubts about efficacy, complications and cost exist, questioning the justification of an uncertain prophylaxis in patients with inhibitors. Activated prothrombin complex concentrate (aPCC) has been used in more than 70 haemophilia patients with inhibitors in different clinical situations. aPCC prophylaxis seems to be safe and effective for the reduction of bleeding episodes in some patients. Recombinant activated factor VII (rFVIIa) has been employed prophylactically in over 44 haemophilia patients with inhibitors; 22 patients were included in the only randomized, prospective clinical trial of bypassing agents in prophylaxis. Bleeding frequency was reduced and this reduction was maintained during the postprophylaxis period. No thromboembolic events were reported during prophylaxis with rFVIIa. Although the effect of aPCC can last longer than that of rFVIIa, their efficacy rates are similar, suggesting that the biological effect of rFVIIa is actually much longer than indicated by its short plasma half-life. aPCC contains residual factor VIII antigen and may cause an anamnestic response in the inhibitor titre. This is crucial when immune tolerance induction is postponed to allow the inhibitor titre to decline to < 10 Bethesda Units. In this setting, aPCC is not recommended as a first-line prophylaxis because of its potential to protract anamnesis, and rFVIIa is the preferred agent.