Discovery of Clinical Candidate 1-{[(2S,3S,4S)-3-Ethyl-4-fluoro-5-oxopyrrolidin-2-yl]methoxy}-7-methoxyisoquinoline-6-carboxamide (PF-06650833), a Potent, Selective Inhibitor of Interleukin-1 Receptor Associated Kinase 4 (IRAK4), by Fragment-Based Drug Design.

Through fragment-based drug design focused on engaging the active site of IRAK4 and leveraging three-dimensional topology in a ligand-efficient manner, a micromolar hit identified from a screen of a Pfizer fragment library was optimized to afford IRAK4 inhibitors with nanomolar potency in cellular assays. The medicinal chemistry effort featured the judicious placement of lipophilicity, informed by co-crystal structures with IRAK4 and optimization of ADME properties to deliver clinical candidate PF-06650833 (compound 40). This compound displays a 5-unit increase in lipophilic efficiency from the fragment hit, excellent kinase selectivity, and pharmacokinetic properties suitable for oral administration.

Effect of JAK Inhibitors on Release of CXCL9, CXCL10 and CXCL11 from Human Airway Epithelial Cells.

Background: CD8+ T-cells are located in the small airways of COPD patients and may contribute to pathophysiology. CD8+ cells express the chemokine receptor, CXCR3 that binds CXCL9, CXCL10 and CXCL11, which are elevated in the airways of COPD patients. These chemokines are released from airway epithelial cells via activation of receptor associated Janus kinases (JAK).

Fragment based discovery of a novel and selective PI3 kinase inhibitor.

We report the use of fragment screening and fragment based drug design to develop a PI3γ kinase fragment hit into a lead. Initial fragment hits were discovered by high concentration biochemical screening, followed by a round of virtual screening to identify additional ligand efficient fragments. These were developed into potent and ligand efficient lead compounds using structure guided fragment growing and merging strategies.

Design and synthesis of inhaled p38 inhibitors for the treatment of chronic obstructive pulmonary disease.

This paper describes the identification and optimization of a novel series of DFG-out binding p38 inhibitors as inhaled agents for the treatment of chronic obstructive pulmonary disease. Structure based drug design and "inhalation by design" principles have been applied to the optimization of the lead series exemplied by compound 1a. Analogues have been designed to be potent and selective for p38, with an emphasis on slow enzyme dissociation kinetics to deliver prolonged lung p38 inhibition.