Discovery of Edecesertib (GS-5718): A Potent, Selective Inhibitor of IRAK4

Interleukin-1 receptor-associated kinase 4 (IRAK4) activity mediates pro-inflammatory signaling and cytokine production downstream of toll-like and interleukin-1 receptors (TLR, IL-1R). Selective IRAK4 inhibitors have generated interest as potential treatments for inflammatory diseases. Herein, we report the discovery of GS-5718 (edecesertib), a potent, selective, orally bioavailable IRAK4 inhibitor. Key to this endeavor were efforts undertaken to improve the chemical series' profile after a significant hERG liability was encountered for an early compound. GS-5718 was safe and well-tolerated in IND-enabling preclinical animal toxicity studies, demonstrated efficacy in a mouse NZB lupus model, and additionally demonstrated human pharmacokinetic properties suitable for once-daily administration. Edecesertib is currently under clinical evaluation for the treatment of lupus.