CGI-1746 is a small-molecule Bruton's tyrosine kinase (Btk) inhibitor chemotype with a new binding mode that stabilizes an inactive nonphosphorylated enzyme conformation. CGI-1746 has exquisite selectivity for Btk and inhibits both auto- and transphosphorylation steps necessary for enzyme activation. CGI-1746 is useful for heumatoid Arthritis