Discovery of BGB-8035, a Highly Selective Covalent Inhibitor of Bruton's Tyrosine Kinase for B-Cell Malignancies and Autoimmune Diseases.

Bruton's tyrosine kinase (BTK) plays an essential role in B-cell receptor (BCR)-mediated signaling as well as the downstream signaling pathway for Fc receptors (FcRs). Targeting BTK for B-cell malignancies by interfering with BCR signaling has been clinically validated by some covalent inhibitors, but suboptimal kinase selectivity may lead to some adverse effects, which also makes the clinical development of autoimmune disease therapy more challenging. The structure-activity relationship (SAR) starting from zanubrutinib (-) leads to a series of highly selective BTK inhibitors, in which - is located in the ATP binding pocket and has similar hinge binding to ATP but exhibits high selectivity over other kinases (EGFR, Tec, etc.). With an excellent pharmacokinetic profile as well as demonstrated efficacy studies in oncology and autoimmune disease models, - has been declared a preclinical candidate. However, - showed an inferior toxicity profile compared to that of -.