Search

Additional information to provide an insight into the full kinase selectivity profile of AT7519 and full details of its pharmakokinetic parameters

PDF file - 81K, Supplementary data comprising the materials and methods for (i) crystallography (ii) gene expression studies (iii) siRNA studies and Supplementary Figure legends 1-7

XLS file - 703K, Gene expression data for CCT128930: Genes that showed at least a 1.5 Fold Change in at least one treated sample compared to vehicle control and were differentially expressed between the treatment groups (Welch ANOVA FDR5%)

Purpose: Deregulated phosphatidylinositol 3-kinase pathway signaling through AGC kinases including AKT, p70S6 kinase, PKA, SGK and Rho kinase is a key driver of multiple cancers. The simultaneous inhibition of multiple AGC kinases may increase antitumor activity and minimize clinical resistance compared with a single pathway component.Experimental Design: We investigated the detailed pharmacology and antitumor activity of the novel clinical drug candidate AT13148, an oral ATP-competitive multi-AGC kinase inhibitor. Gene expression microarray studies were undertaken to characterize the molecular mechanisms of action of AT13148.Results: AT13148 caused substantial blockade of AKT, p70S6K, PKA, ROCK, and SGK substrate phosphorylation and induced apoptosis in a concentration and time-dependent manner in cancer cells with clinically relevant genetic defects in vitro and in vivo. Antitumor efficacy in HER2-positive, PIK3CA-mutant BT474 breast, PTEN-deficient PC3 human prostate cancer, and PTEN-deficient MES-SA uterine tumor xenografts was shown. We show for the first time that induction of AKT phosphorylation at serine 473 by AT13148, as reported for other ATP-competitive inhibitors of AKT, is not a therapeutically relevant reactivation step. Gene expression studies showed that AT13148 has a predominant effect on apoptosis genes, whereas the selective AKT inhibitor CCT128930 modulates cell-cycle genes. Induction of upstream regulators including IRS2 and PIK3IP1 as a result of compensatory feedback loops was observed.Conclusions: The clinical candidate AT13148 is a novel oral multi-AGC kinase inhibitor with potent pharmacodynamic and antitumor activity, which shows a distinct mechanism of action from other AKT inhibitors. AT13148 will now be assessed in a first-in-human phase I trial. Clin Cancer Res; 18(14); 3912–23. ©2012 AACR.

Cyclin-dependent kinases (CDK), and their regulatory cyclin partners, play a central role in eukaryotic cell growth, division, and death. This key role in cell cycle progression, as well as their deregulation in several human cancers, makes them attractive therapeutic targets in oncology. A series of CDK inhibitors was developed using Astex's fragment-based medicinal chemistry approach, linked to high-throughput X-ray crystallography. A compound from this series, designated AT7519, is currently in early-phase clinical development. We describe here the biological characterization of AT7519, a potent inhibitor of several CDK family members. AT7519 showed potent antiproliferative activity (40-940 nmol/L) in a panel of human tumor cell lines, and the mechanism of action was shown here to be consistent with the inhibition of CDK1 and CDK2 in solid tumor cell lines. AT7519 caused cell cycle arrest followed by apoptosis in human tumor cells and inhibited tumor growth in human tumor xenograft models. Tumor regression was observed following twice daily dosing of AT7519 in the HCT116 and HT29 colon cancer xenograft models. We show that these biological effects are linked to inhibition of CDKs in vivo and that AT7519 induces tumor cell apoptosis in these xenograft models. AT7519 has an attractive biological profile for development as a clinical candidate, and the tolerability and efficacy in animal models compare favorably with other CDK inhibitors in clinical development. Studies described here formed the biological rationale for investigating the potential therapeutic benefit of AT7519 in cancer patients. [Mol Cancer Ther 2009;8(2):324–32]

Supplementary Data from Biological characterization of AT7519, a small-molecule inhibitor of cyclin-dependent kinases, in human tumor cell lines

XLS file - 66K, Genes that showed at least a 1.5 Fold Change in at least one treated sample compared to vehicle control and were differentially expressed between the treatment groups (Welch ANOVA FDR5%) for both CCT128930 and AT13148

PDF file - 553K, Supplementary Figure 1. Phosphorylation of AKT substrates remains suppressed, despite pSer473 AKT induction. Supplementary Figure 2. The pharmacokinetic-pharmacodynamic profile and antitumor activity of AT13148 in PTEN-deficient PC3 human prostate cancer xenografts. Supplementary Figure 3. Pharmacodynamic biomarker study of AT13148(40mg/kg) in MES-SA human tumor xenografts. Supplementary Figure 4. The antitumour activity of AT13148 in mutant KRAS A549 human lung cancer xenografts. Supplementary Figure 5. Mouse body weight data for the MES-SA (Figure 4B) and BT474 (Figure 4C) efficacy studies. Supplementary Figure 6. The effect of AT13148 versus CCT128930 on apoptosis and cell cycle distribution in U87MG human glioblastoma cells. Supplementary Figure 7. Differential effects of 24h treatment of 10M each of the AGC kinase inhibitor AT13148 and the selective AKT inhibitor CCT128930 on cell cycle effects in PTEN-deficient U87MG human glioblastoma cells. Supplementary Table 1. Summary of the inhibitory activity of 10��M AT13148 against in vitro. Supplementary Table 2. Summary of the inhibitory activity of AT13148 against a panel of protein kinases Supplementary Table 3. Summary of the in vitro cytotoxicity of AT13148 against a panel of human tumor cell lines harboring different defects in the PI3K-AKT signaling pathway. Supplementary Table 4. Summary of the pharmacokinetics of AT13148 in mouse plasma and tissues following iv or oral administration