BI-1347

BI-1347 is a potent and selective small molecule inhibitor of Cyclin-Dependent Kinase 8 (CDK8), developed by Boehringer Ingelheim. It functions as an immunomodulatory agent by enhancing the activity of natural killer (NK) cells. CDK8 normally suppresses NK cell cytolytic function through the phosphorylation of STAT1 at Ser727; by inhibiting CDK8, BI-1347 promotes the production of key cytolytic molecules such as perforin and granzyme B. In preclinical studies, BI-1347 has demonstrated efficacy as a single agent in hematological malignancies like myeloid leukemia and lymphoma, and has shown potential in solid tumors like melanoma and breast cancer, particularly when used in pulsatile dosing schedules or in combination with other immunomodulators like SMAC mimetics.