BTK Inhibitors in Haematology: Beyond B Cell Malignancies

Autoreactive B-cells are crucial in the pathogenesis of both haematologic and non-haematologic autoimmune disorders. Therapies targeting B cells and autoantibodies are widely used in clinical practice, however, many patients fail to respond to conventional treatments. An evolving understanding of molecular mechanisms underlying autoimmune haematologic disorders has facilitated the development of novel therapies, including Bruton's Tyrosine Kinase (BTK) inhibitors. BTK is fundamental in B-cell survival, and its inhibition has been used in a wide range of autoimmune and inflammatory conditions, as well as mature B cell malignancies. This paper reviews the role of BTK in immunity, evolution of BTK inhibitors, and the emerging evidence for BTK inhibitors in autoimmune haematologic conditions, primarily immune thrombocytopenia (ITP), and potential future clinical applications.