AS-2444697 is an inhibitor of interleukin-1 receptor-associated kinase 4 (IRAK4; IC50 = 21 nM).1 It is greater than 30-fold selective for IRAK4 over a panel of 146 kinases, but is less than 10-fold selective over PDGFRα, PDGFRβ, TrkA, TrkC, CLK1, Itk, and FLT3. AS-2444697 inhibits IL-1β-induced IL-6 production and LPS-induced TNF-α production in cellular assays (IC50s = 250 and 47 nM, respectively). It is efficacious in rat models of adjuvant- and collagen-induced arthritis (ED50s = 2.7 and 1.6 mg/kg, respectively). AS-2444697 (0.3-3 mg/kg, twice daily) reduces urinary protein excretion, the development of interstitial fibrosis and glomerulosclerosis, and renal mRNA expression of genes encoding IL-1β, IL-6, TNF-α, and chemokine (C-C motif) ligand 2 (CCL2) without affecting blood pressure in the 5/6 nephrectomized rat model of chronic kidney disease.2

|2. Kondo, M., Tahara, A., Hayashi, K., et al. Renoprotective effects of novel interleukin-1 receptor-associated kinase 4 inhibitor AS2444697 through anti-inflammatory action in 5/6 nephrectomized rats. Naunyn Schmiedebergs Arch. Pharmacol. 287(10), 909-919 (2014).