HS271 is a highly potent, orally active and selective IRAK4 inhibitor, with an IC 50 of 7.2 μM. HS271 exhibits superior enzymatic and cellular activities, as well as excellent pharmacokinetic properties In Vivo HS271 (15-150 mg/kg) displays robust in vivo antiinflammatory efficacy as evaluated in rat models of LPS induced TNFα production collageninduced arthritis . HS271 exhibits a t 1/2 of 3.3 h and C max of 2107 ng/mL . HS271 is stable in liver microsome assays across other species, including rat, mouse, monkey, and human . HS271 exhibits oral bioavailability of 67.3%, 58.2%, 14.4&% and 49% in mouse, rat, dog and monkey, respectively . MCE has not independently confirmed the accuracy of these methods. They are for reference only. Animal Model: A rat model of collagen induced arthritis (CIA) . Dosage: 15, 50, 150 mg/kg. Administration: PO, once daily. Result: Led to a significant reduction in paw swelling as compared to vehicle control, with a minimum effective dose at 15 mg/kg QD. Notably, at 150 mg/kg QD, HS271 eliminated the paw swelling. Form:Solid IC50& Target:IRAK4 7.2 μM (IC 50 )