Nicole Buschmann

Discovery of a Dihydroisoquinolinone Derivative (NVP-CGM097): A Highly Potent and Selective MDM2 Inhibitor Undergoing Phase 1 Clinical Trials in p53wt Tumors

As a result of our efforts to discover novel p53:MDM2 protein-protein interaction inhibitors useful for treating cancer, the potent and selective MDM2 inhibitor NVP-CGM097 (1) with an excellent in vivo profile was selected as a clinical candidate and is currently in phase 1 clinical development. This article provides an overview of the discovery of this new clinical p53:MDM2 inhibitor. The following aspects are addressed: mechanism of action, scientific rationale, binding mode, medicinal chemistry, pharmacokinetic and pharmacodynamic properties, and in vivo pharmacology/toxicology in preclinical species.

2-Formylpyridyl Ureas as Highly Selective Reversible-Covalent Inhibitors of Fibroblast Growth Factor Receptor 4

As part of a project to identify FGFR4 selective inhibitors, scaffold morphing of a 2-formylquinoline amide hit identified series of 2-formylpyridine ureas (2-FPUs) with improved potency and physicochemical properties. In particular, tetrahydronaphthyridine urea analogues with cellular activities below 30 nM have been identified. Consistent with the hypothesized reversible-covalent mechanism of inhibition, the 2-FPUs exhibited slow binding kinetics, and the aldehyde, as the putative electrophile, could be demonstrated to be a key structural element for activity.

Bioorthogonal Probes for the Study of MDM2-p53 Inhibitors in Cells and Development of High-Content Screening Assays for Drug Discovery

To study the behavior of MDM2-p53 inhibitors in a disease-relevant cellular model, we have developed and validated a set of bioorthogonal probes that can be fluorescently labeled in cells and used in high-content screening assays. By using automated image analysis with single-cell resolution, we could visualize the intracellular target binding of compounds by co-localization and quantify target upregulation upon MDM2-p53 inhibition in an osteosarcoma model. Additionally, we developed a high-throughput assay to quantify target occupancy of non-tagged MDM2-p53 inhibitors by competition and to identify novel chemical matter. This approach could be expanded to other targets for lead discovery applications.

Abstract 1798: Mechanistic study of NVP-CGM097: a potent, selective and species specific inhibitor of p53-Mdm2

Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA An effective strategy to restore p53 activity in cancer cells containing wild type p53 is to inhibit the Mdm2-p53 protein-protein interaction (PPI). NVP-CGM097 is a novel PPI inhibitor under evaluation in a Phase I clinical trial. It binds to the p53 binding-site of the Mdm2 protein, disrupting the interaction between both proteins, leading to an activation of the p53 pathway. The main biophysical and biochemical inhibitory characteristics of NVP-CGM097 are presented here. These include an affinity constant for Mdm2 in the nanomolar range and a selectivity of 3 orders of magnitude vs. Mdm4. The binding kinetics of NVP-CGM097 to Mdm2 are characterized by a high association rate constant (Kon =37 x 106 M-1.s-1) and a moderate dissociation rate constant (Koff =0.071 s-1). Additionally, NVP-CGM097 exhibits an 8-fold greater affinity for Mdm2 over Nutlin-3 due to a longer residence time of the Mdm2-inhibitor complex. Moreover, biochemical studies have revealed the species specificity of NVP-CGM097 with human Mdm2 being inhibited more strongly than the dog, mouse or rat forms of the protein. This was confirmed in cellular assays where NVP-CGM097 treatment resulted in induction of p53 target gene expression (p21, PUMA and Mdm2) only in human, but not in dog, mouse or rat cell lines. Citation Format: Therese Valat, Keiichi Masuya, Frederic Baysang, Genevieve Albrecht, Nicole Buschmann, Dirk Erdmann, Pascal Furet, Tobias Gabriel, Francois Gessier, Francesco Hofmann, Philipp Holzer, Joerg Kallen, Carole Pissot-Solderman, Stefan Stutz, Patrick Chene, Sebastien Jeay. Mechanistic study of NVP-CGM097: a potent, selective and species specific inhibitor of p53-Mdm2. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1798. doi:10.1158/1538-7445.AM2014-1798

Abstract 1797: Discovery of NVP-CGM097, a highly potent and optimized small molecule inhibitor of Mdm2 under evaluation in a Phase I clinical trial

Activation of p53 by blocking the p53-Mdm2 interaction using non-peptidic small-molecule inhibitors is being pursued as a promising cancer therapeutic strategy. In the present study, we show the identification of NVP-CGM097, a novel, highly optimized, and selective inhibitor of the p53-Mdm2 interaction. NVP-CGM097 binds to human Mdm2 protein with a Ki value of 1.3 nM, activates p53 in human cells and induces robust p53-dependent cell cycle arrest and apoptosis in human p53 wild-type tumor cells. Its activity and selectivity has been tested and confirmed across a large panel of cancer cell lines from the Cancer Cell Line Encyclopedia. Importantly, NVP-CGM097 displays desirable pharmacokinetic and pharmacodynamic profiles in animals together with excellent oral bioavailability, which triggers rapid and sustained activation of p53-dependent pharmacodynamic biomarkers resulting in tumor regression in multiple xenografted models of p53 wild-type human cancer. The validation and understanding of its mechanism of action, the overall favorable drug-like properties and the characterization of its on-target toxicological profile in preclinical species strongly supported the initiation of Phase I clinical trials with NVP-CGM097 in pre-selected patients with p53 wild-type tumors. Citation Format: Sebastien Jeay, Joerg Berghausen, Nicole Buschmann, Patrick Chene, Robert Cozens, Dirk Erdmann, Stephane Ferretti, Pascal Furet, Tobias Gabriel, Francois Gessier, Diana Graus-Porta, Francesco Hofmann, Philipp Holzer, Moriko Ito, Edgar Jacoby, Michael Jensen, Joerg Kallen, Marc Lang, Joanna Lisztwan, Masato Murakami, Carole Pissot-Soldermann, Stephan Ruetz, Caroline Rynn, Dario Sterker, Stefan Stutz, Therese Valat, Marion Wiesmann, Keiichi Masuya. Discovery of NVP-CGM097, a highly potent and optimized small molecule inhibitor of Mdm2 under evaluation in a Phase I clinical trial. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1797. doi:10.1158/1538-7445.AM2014-1797

Abstract DDT01-01: Discovery of CGM097 as a novel Mdm2 inhibitor

The antiproliferative transcriptional activity of the p53 tumor suppressor is inhibited by the binding of its transactivation domain to the regulator protein Mdm2. Overexpression of Mdm2 or amplification of its gene, leading to a loss of p53 function, has been observed in various tumors. An attractive approach to restore p53 activity in such tumors and to inhibit their growth is to prevent the association of the two proteins by blocking the p53 binding pocket of Mdm2 with a small molecule. In this presentation, we report how the starting point of CGM097 was discovered and how innovative medicinal chemistry efforts led to further optimization of the potency and physico-chemical properties, resulting in CGM097, a novel, highly optimized, and selective inhibitor of the p53-Mdm2 interaction. Citation Format: Keiichi Masuya, Pascal Furet, Stefan Stutz, Philipp Holzer, Carole Pissot-Soldmann, Nicole Buschmann, Therese Valat, Stephane Ferretti, Stephan Ruetz, Caroline Rynn, Joerg Berghausen, Edgar Jacoby, Marc Lang, Tobias Gabriel, Francesco Hofmann, Joerg Kallen, Sebastien Jeay, Francois Gessier. Discovery of CGM097 as a novel Mdm2 inhibitor. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr DDT01-01. doi:10.1158/1538-7445.AM2014-DDT01-01