The first descriptions of haemophilia A were reported in the second century AD, with the first modern description by John Conrad Otto in 1803. Historically, the natural history of haemophilia A was associated with very high rates morbidity and mortality, often following trivial accidents. Although treatment options for haemophilia A have been revolutionised in recent decades, haemophilia A remains a hereditary disease of concern and factor replacement products remain the mainstay of treatment.

As such, patients with haemophilia can carry huge burdens, particularly when a complication such as a FVIII inhibitor is present. A recently approved novel therapeutic, Emicizumab-kxwh, has offered an unexpected and alternative approach to haemophilia A therapy. This recombinant, humanized, bi-specific antibody provides patients with effective haemostasis, empowerment of self-administration, and an overall improved quality of life. For patients with FVIII inhibitors, emicizumab-kxwh offers a simple treatment mechanism that can efficiently overcome deleterious antibodies as the antibody bridges FIX and FX, mimicking the function of FVIII without sharing structural homology or biochemical properties. Considering this, the literature and clinical trials available to date have been critically analyzed and discussed herein. This review aims to explore the advantages, disadvantages, and any potential need for caution with emicizumab-kxwh.