Acquired hemophilia due to immune checkpoint inhibitors: a case series introducing emicizumab treatment. (2025)

[BACKGROUND] Acquired hemophilia A (AHA) is a rare but potentially life-threatening autoimmune bleeding disorder and immune-related adverse event (irAE) associated with immune checkpoint inhibitors (ICI). This study discusses 3 new cases of ICI-induced AHA from Belgium and the SERIO-Side Effect Registry Immuno-Oncology (www.serio-registry.org), placing them in the context of existing literature.

[METHODS] One case was encountered at a tertiary care center in Belgium. SERIO was queried and yielded another 2 cases. A comprehensive literature review using PubMed identified 8 additional cases.

[RESULTS] A total of 11 patients were analyzed, with a median age of 68 years (range: 56-71), 10 were male. Most (9/11) were treated with anti-PD-1 monotherapy. In 5 cases, toxicity appeared before the