Atuveciclib (BAY-1143572)

BAY 1143572 is a potent and highly selective CDK9 inhibitor (IC50 CDK9/CycT1: 13 nM, ratio of IC50 values CDK2/CDK9: 100). Outside the CDK family, submicromolar inhibitory activity was only recorded against GSK3 kinase (IC50 GSK3α: 45 nM, GSK3β: 87 nM). BAY 1143572 demonstrates antiproliferative activity against HeLa cells (IC50 = 920 nM) and MOLM-13 cells (IC50 = 310 nM). It also demonstrates improved Caco-2 permeability and a decreased efflux ratio (P_{appA→B: 35 nm/s, ER: 6) relative to lead compound BAY‐958 (PappA→B: 22 nm/s, ER: 15)^[1].}

In an in vivo pharmacokinetic study in rats, BAY 1143572 showed low blood clearance (CL_b 1.1 L/h/kg). The volumes of distribution (Vss) of BAY 1143572 is 1.0 L/kg. BAY 1143572 shows significantly improved oral bioavailability of 54 %. The blood/plasma ratios is about 1. It does not show significant inhibition of cytochrome P450 activity, with IC50 values >20 μM^[1]. The administration of BAY 1143572 in immunocompromized NOD/Shi-scid/IL-2Rγ ^null (NOG) mice xenografted with patient-derived ATL cells greatly reduced the infiltration of ATL cells into organs, such as liver and bone marrow. Decreased human soluble IL2R levels in serum were also observed, which indicated a reduction of ATL tumor burden^[2].