Small Molecule Reversible Inhibitors of Bruton’s Tyrosine Kinase (BTK): Structure–Activity Relationships Leading to the Identification of 7-(2-Hydroxypropan-2-yl)-4-2-methyl-3-(4-oxo-3,4-dihydroquinazolin-3-yl)phenyl-9H-carbazole-1-carboxamide (BMS-935177)

Bruton's tyrosine kinase (BTK) belongs to the TEC family of nonreceptor tyrosine kinases and plays a critical role in multiple cell types responsible for numerous autoimmune diseases. This article will detail the structure-activity relationships (SARs) leading to a novel second generation series of potent and selective reversible carbazole inhibitors of BTK. With an excellent pharmacokinetic profile as well as demonstrated in vivo activity and an acceptable safety profile, 7-(2-hydroxypropan-2-yl)-4-2-methyl-3-(4-oxo-3,4-dihydroquinazolin-3-yl)phenyl-9H-carbazole-1-carboxamide 6 (BMS-935177) was selected to advance into clinical development.