Discovery, Optimization and Evaluation of Potent and Highly Selective PI3Kγ-PI3Kδ Dual Inhibitors.

An electronic density model was developed and used to identify a novel pyrrolotriazinone replacement for a quinazolinone, a commonly used moiety to impart selectivity in inhibitors for PI3K gamma and PI3K delta. Guided by molecular docking, this new specificity piece was then linked to the hinge-binding region of the inhibitor using a novel cyclic moiety. Further structure-activity relationship optimization around the hinge region led to the discovery of candidate 26, a highly potent and selective PI3K gamma-PI3K delta dual inhibitor with favorable drug metabolism and pharmacokinetic properties in preclinical species.