AMG319

AMG319 is a potent and selective PI3Kδ kinase inhibitor with IC₅₀ of 18 nM. IC50 & Target: IC50: 18 nM (PI3Kδ), 850 nM (PI3Kγ), 2.7 μM (PI3Kβ), 33 μM (PI3Kα)^[1] In Vitro: AMG319 inhibits PI3Kδ, PI3Kγ, PI3Kβ and PI3Kα with IC₅₀s of 18 nM, 850 nM, 2.7 μM and 33 μM, respectively. AMG319, a compound with an IC₅₀ of 16 nM in a human whole blood assay (HWB), excellent selectivity over a large panel of protein kinases, and a high level of in vivo efficacy as measured by two rodent disease models of inflammation. AMG319 has minimal CYP3A4/2D6 inhibition and does not inhibit CYPs (1A2, 2C8, 2C9, 2C19, 2E1, all >20 μM). There is no time dependent inhibition (TDI) against CYPs 3A4, 2D6, 1A2, and 2C9 nor CYP induction (3A4, 2D6, 1A2, 2B6) as measured in hepatocytes. AMG319 is clean in a hERG binding assay (>25 μM), and an Ames micronucleus test proved negative. AMG319 has minimal effects in a BSEP assay up to >200 μM. Additionally, AMG319 is clean in a large side effect profiling panel (CEREP) and has no activity in a large panel of 359 unique protein kinases tested at 10 μM drug concentration^[1]. In Vivo: The study is performed to determine the correlation between biochemical coverage (i.e., pAKT) with functional activity in vivo. AMG319 achieves this coverage at the 3 mg/kg level, which also coveres the human whole blood assay (HWB) (CD-69) IC₉₀ at trough for a full 24 h period. The lower doses 0.1, 0.3, and 1 mg/kg cover trough concentrations between the HWB IC₅₀ and IC₉₀ and evince partial efficacy. Similarly, the plasma concentration of AMG319 covers the IC₉₀ at the 1 mg/kg dose of the mouse anti-IgM pAKT in vitro assay^[1].