The Lab Oddity Prevails: Discovery of Pan-Cdk Inhibitor (R)- S-Cyclopropyl-S-(4-{[4-{[(1R,2R)-2-Hydroxy-1-Methylpropyl]Oxy}-5-(Trifluoromethyl)Pyrimidin-2-Yl]Amino}Phenyl)Sulfoximide (Bay 1000394) for the Treatment of Cancer.

Abstract Lead optimization of a high-throughput screening hit led to the rapid identification of aminopyrimidine ZK 304709, a multitargeted CDK and VEGF-R inhibitor that displayed a promising preclinical profile. Nevertheless, ZK 304709 failed in phase I studies due to dose-limited absorption and high inter-patient variability, which was attributed to limited aqueous solubility and off-target activity against carbonic anhydrases. Further lead optimization efforts to address the off-target activity profile finally resulted in the introduction of a sulfoximine group, which is still a rather unusual approach in medicinal chemistry. However, the sulfoximine series of compounds quickly revealed very interesting properties, culminating in the identification of the nanomolar pan-CDK inhibitor BAY 1000394, which is currently being investigated in phase I clinical trials.