Conception Nemecek

2-Chloro-3-pyridin-3-yl-5,6,7,8-tetrahydroindolizine-1-carboxamide (CMV423), a new lead compound for the treatment of human cytomegalovirus infections.

Human cytomegalovirus (HCMV) remains one of the major pathogens in immunocompromised patients (AIDS and transplants) and the main cause for congenital infections leading from slight cognitive defects up to severe mental retardation. The drugs that are currently available for the treatment of HCMV infections, i.e. ganciclovir, foscarnet and cidofovir, are all acting at the level of the viral DNA polymerase. Here we describe an entirely new molecule, the 2-chloro-3-pyridin-3-yl-5,6,7,8-tetrahydroindolizine-1-carboxamide (CMV423), that shows very potent in vitro activity against HCMV. CMV423 is highly active against HCMV reference strains and clinical isolates, but also against those strains, isolated from patients or emerging after in vitro selection, that are resistant to either ganciclovir, foscarnet or cidofovir. CMV423 also showed activity in two ex vivo models, that are both highly relevant for the pathophysiology of HCMV, the retinal pigment epithelial and the bone marrow stromal cell assays. Viral antigen expression analysis by flow cytometry, as well as time of addition experiments, confirmed that CMV423 acts on a step of the viral replicative cycle that precedes the DNA polymerase step and, most likely, coincides with the immediate early (IE) antigen synthesis. Finally, CMV423 combined with either ganciclovir, foscarnet or cidofovir in checkerboard experiments demonstrated a highly synergistic activity.

Discovery of the first non-ATP competitive IGF-1R kinase inhibitors: Advantages in comparison with competitive inhibitors

A new series of IGF-1R inhibitors related to hydantoins were identified from a lead originating from HTS. Their noncompetitive property as well as their slow binding characteristics provided a series of compounds with unique selectivity and excellent cellular activities.

Design of Potent IGF1‐R Inhibitors Related to Bis‐azaindoles

From an azaindole lead, identified in high throughput screen, a series of potent bis‐azaindole inhibitors of IGF1‐R have been synthesized using rational drug design and SAR based on a in silico binding mode hypothesis. Although the resulting compounds produced the expected improved potency, the model was not validated by the co‐crystallization experiments with IGF1‐R.

Discovery and Pharmacokinetic and Pharmacological Properties of the Potent and Selective MET Kinase Inhibitor 1-{6-[6-(4-Fluorophenyl)-[1,2,4]triazolo[4,3-b]pyridazin-3-ylsulfanyl]benzothiazol-2-yl}-3-(2-morpholin-4-ylethyl)urea (SAR125844).

The HGF/MET pathway is frequently activated in a variety of cancer types. Several selective small molecule inhibitors of the MET kinase are currently in clinical evaluation, in particular for NSCLC, liver, and gastric cancer patients. We report herein the discovery of a series of triazolopyridazines that are selective inhibitors of wild-type (WT) MET kinase and several clinically relevant mutants. We provide insight into their mode of binding and report unprecedented crystal structures of the Y1230H variant. A multiparametric chemical optimization approach allowed the identification of compound 12 (SAR125844) as a development candidate. In this chemical series, absence of CYP3A4 inhibition was obtained at the expense of satisfactory oral absorption. Compound 12, a promising parenteral agent for the treatment of MET-dependent cancers, promoted sustained target engagement at tolerated doses in a human xenograft tumor model. Preclinical pharmacokinetics conducted in several species were predictive for the observed pharmacokinetic behavior of 12 in cancer patients.

The Selective Intravenous Inhibitor of the MET Tyrosine Kinase SAR125844 Inhibits Tumor Growth in MET-Amplified Cancer

Activation of the MET/HGF pathway is common in human cancer and is thought to promote tumor initiation, metastasis, angiogenesis, and resistance to diverse therapies. We report here the pharmacologic characterization of the triazolopyridazine derivative SAR125844, a potent and highly selective inhibitor of the MET receptor tyrosine kinase (RTK), for intravenous administration. SAR125844 displayed nanomolar activity against the wild-type kinase (IC50 value of 4.2 nmol/L) and the M1250T and Y1235D mutants. Broad biochemical profiling revealed that SAR125844 was highly selective for MET kinase. SAR125844 inhibits MET autophosphorylation in cell-based assays in the nanomolar range, and promotes low nanomolar proapoptotic and antiproliferative activities selectively in cell lines with MET gene amplification or pathway addiction. In two MET-amplified human gastric tumor xenograft models, SNU-5 and Hs 746T, intravenous treatment with SAR125844 leads to potent, dose- and time-dependent inhibition of the MET kinase and to significant impact on downstream PI3K/AKT and RAS/MAPK pathways. Long duration of MET kinase inhibition up to 7 days was achieved with a nanosuspension formulation of SAR125844. Daily or every-2-days intravenous treatment of SAR125844 promoted a dose-dependent tumor regression in MET-amplified human gastric cancer models at tolerated doses without treatment-related body weight loss. Our data demonstrated that SAR125844 is a potent and selective MET kinase inhibitor with a favorable preclinical toxicity profile, supporting its clinical development in patients with MET-amplified and MET pathway–addicted tumors. Mol Cancer Ther; 14(2); 384–94. ©2014 AACR.

Versatile Methods for the Synthesis of 2-Amino-6-trifluoromethoxy-(nitro)benzothiazoles

Abstract Convenient and regioselective syntheses of all three isomers of mononitro-6-trifluoromethoxy-benzothiazoles, starting from 2-amino-6-trifluoromethoxy-benzothiazole (riluzole) are described.

Abstract 2911: SAR125844: a potent and selective ATP-competitive inhibitor of MET kinase

Proceedings: AACR 103rd Annual Meeting 2012‐‐ Mar 31‐Apr 4, 2012; Chicago, IL The tyrosine kinase MET is a membrane receptor that is essential for embryonic development and wound healing in normal cells. Stimulation of MET by its natural ligand, the hepatocyte growth factor (HGF), induces cell proliferation, migration, and invasion. Abnormal MET activation (over-expression of MET protein, amplification or mutations of the MET gene) has been observed in multiple human cancer types. We report herein the discovery of a potent and selective small molecule inhibitor (SAR125844) with potential therapeutic application in cancer patients with deregulated MET-dependent malignancies. Our initial hit identification approach was based on the biochemical screen of an in-house kinase inhibitor biased library where a series of benzimidazole sulfonate derivatives were identified with sub-micromolar MET inhibition. In particular, the initial hit exhibited an IC50 of 140 nM vs MET but it also had strong affinity for CDK9 (IC50= 6 nM), a CDK isoform involved in gene transcription. Chemical modifications of the series to dial out CDK9 affinity and remove potential normal cell cytotoxicity led to a more selective derivative with IC50s of 80nM and 1355nM vs MET and CDK9 respectively. Further sub-structural exploration allowed us to identify a heteorocyclic moiety which was shown by X-ray data to specifically interact with Tyr1230 in a non active conformation of the protein. The resulting highly favourable U-shape mode of binding in MET of representative examples from these series (e.g. IC50= 1nM) was not tolerated in CDK9 (IC50 > 10µM). Final multi-parametric medicinal chemistry optimisation led to SAR125844 with single digit nanomolar antiproliferative activity on MET-amplified cell lines. SAR125844 is highly selective for MET kinase in a panel of 275 kinases tested, with only 5 other protein kinases inhibited at IC50 values below 300 nM. This compound exhibits also satisfactory eADMET in vitro properties and has shown moderate total plasma clearance, large volume of distribution and moderate to long terminal elimination half-life in rats. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2911. doi:1538-7445.AM2012-2911

Abstract 845: In vitro and in vivo pharmacology of SAR125844, a potent and selective intravenous MET kinase inhibitor undergoing Phase I clinical trial

SAR125844 is a potent MET kinase inhibitor for intravenous (IV) administration, with nanomolar activity against the wild-type enzyme (IC50 = 4.2 nM) and some kinase domain mutants, such as M1250T and Y1235D. It is highly selective for MET kinase in a panel of 275 kinases tested, with only 5 other protein kinases inhibited at IC50 values below 300 nM. In cellular assays, SAR125844 inhibits MET autophosphorylation at the nanomolar range (IC50 from 1.4 to 5.1 nM), translating into antiproliferative activity selectively in MET-driven cell lines such as MET-amplified cell lines, with IC50 values in the low nanomolar range and induction of apoptosis. SAR125844 induces a G1 block in the two MET-amplified tumor cell lines tested. Moreover, the compound is also able to inhibit HGF-induced cell migration in PC-3 prostate tumor cell line. In two MET-amplified human gastric tumor xenograft models tested, SNU-5 and Hs 746T, SAR125844 intravenous treatment leads to potent impact on the MET signaling pathway in a dose and time dependent manner, with potent inhibition of MET autophosphorylation, as well as a significant effect on downstream PI3K/AKT and RAS/MAPK pathways. As a single agent, this translates into a dose-dependent antitumor activity in these two xenograft models, with tumor stasis at the lowest active dose and tumor regression at the highly active doses. High loading single dose administration of SAR125844 using a nanosuspension formulation allowed a sustained P-MET inhibition in tumors up to 7 days. In all models, antitumor activity was achieved at well tolerated doses without significant effect on body weight. The observed correlation between P-MET inhibition in the tumor and antitumor activity in preclinical settings suggests that P-MET evaluation in tumor biopsies could be a direct pharmacodynamic biomarker of SAR125844 activity in patients. In order to investigate whether a non-invasive biomarker could also be used as pharmacodynamic read-out, we measured shed-MET (soluble extracellular domain of the MET receptor) in the plasma of tumor-bearing mice and showed that its level correlates with tumor burden in 2 MET-amplified xenograft models. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 845. doi:1538-7445.AM2012-845