New findings on inhibitor development: from registries to clinical studies

<jats:p>The high incidence of inhibitors against factor <jats:styled-content style="fixed-case">VIII</jats:styled-content> (<jats:styled-content style="fixed-case">FVIII</jats:styled-content>) concentrates in patients with haemophilia A has encouraged debate as to whether product‐type plays a role. There is debate in the literature as to whether <jats:styled-content style="fixed-case">rFVIII</jats:styled-content> concentrates are associated with a higher incidence of inhibitors compared to pd<jats:styled-content style="fixed-case">FVIII</jats:styled-content> products. The management of haemophilia in patients with inhibitors includes on‐demand/prophylaxis treatment with bypassing agents, and/or immune tolerance induction (<jats:styled-content style="fixed-case">ITI</jats:styled-content>). However, these options create an economic and emotional burden on patients, their families and healthcare practitioners. Although <jats:styled-content style="fixed-case">ITI</jats:styled-content> eliminates inhibitors successfully in 60–80% of cases, it is costly. Despite high costs, preliminary data from a decision analytical model have indicated that <jats:styled-content style="fixed-case">ITI</jats:styled-content> is economically advantageous compared with on‐demand/prophylactic treatment with bypassing agents. In patients with persistent inhibitors and those who are not candidates for <jats:styled-content style="fixed-case">ITI</jats:styled-content> or have failed <jats:styled-content style="fixed-case">ITI</jats:styled-content>, bleeding‐related mortality and morbidity increase and quality of life decreases, compared with non‐inhibitor patients. This article provides an update on the risk of inhibitor development and discusses best management approaches for patients with high‐risk factors for inhibitor development.</jats:p>