Mutations in MEK1/2 have been described as a resistance mechanism to BRAF/MEK inhibitor treatment. We report the discovery of a novel ATP-competitive MEK1/2 inhibitor with efficacy in wildtype (WT) and mutant MEK12 models. Starting from a HTS hit, we obtained selective, cellularly active compounds that showed equipotent inhibition of WT MEK1/2 and a panel of MEK1/2 mutant cell lines. Using a structure-based approach, the optimization addressed the liabilities by systematic analysis of molecular matched pairs (MMPs) and ligand conformation. Addition of only three heavy atoms to early tool compound 6 removed Cyp3A4 liabilities and increased the cellular potency by 100-fold, while reducing log P by 5 units. Profiling of MAP855, compound 30, in pharmacokinetic-pharmacodynamic and efficacy studies in BRAF-mutant models showed comparable efficacy to clinical MEK1/2 inhibitors. Compound 30 is a novel highly potent and selective MEK1/2 kinase inhibitor with equipotent inhibition of WT and mutant MEK1/2, whose drug-like properties allow further investigation in the mutant MEK setting upon BRAF/MEK therapy.

The discovery, synthesis, and optimization of compound 1 from a high-throughput screening hit to highly potent and selective peroxisome proliferator-activated receptor delta (PPARdelta) agonists are reported. The synthesis and structure-activity relationship in this series are described in detail. On the basis of a general schematic PPAR pharmacophore model, scaffold 1 was divided into headgroup, linker, and tailgroup and successively optimized for PPAR activation using in vitro PPAR transactivation assays. A (2-methylphenoxy)acetic acid headgroup, a flexible linker, and a five-membered heteroaromatic center ring with two hydrophobic aryl substituents were required for efficient and selective PPARdelta activation. The fine-tuning of these aryl substituents led to an array of highly potent and selective compounds such as compound 38c, displaying an excellent pharmacokinetic profile in mouse. In an in vivo acute dosing model, selected members of this array were shown to induce the expression of pyruvate dehydrogenase kinase-4 (PDK4) and uncoupling protein-3 (UCP3), genes that are known to be involved in energy homeostasis and regulated by PPARdelta in skeletal muscle.

The lead optimization of a novel series of benzo[a] carbazole-based small molecule agonists of the thrombopoietin (Tpo) receptor is reported. The chemical instability of the dihydro-benzo[a] carbazole lead 2 was successfully addressed in the design and evaluation of compounds which also demonstrated improved potency compared to 2. Members of the scaffold have been identified which are full agonists that demonstrate cellular functional potency < 50 nM. Analog 21 demonstrates equivalent efficacy in the human megakaryocyte differentiation (CFU-mega) assay compared to Eltrombopag(TM). (C) 2008 Elsevier Ltd. All rights reserved.

A novel series of benzo[a]carbazole-based small molecule agonists of the thrombopoietin (Tpo) receptor is reported. Starting from a 3.4 microM high throughput screen hit, members of this series have been identified which are full agonists with functional potency <50 nM and oral bioavailability in mice.

We report the identification of a novel series of trisubstituted isoxazoles as PPAR activators from a high-throughput screen. A series of structural optimizations led to improved efficacy and excellent functional receptor selectivity for PPAR delta. The isoxazoles represent a series of agonists which display a scaffold that lies outside the typical PPAR agonist motif. (c) 2006 Elsevier Ltd. All rights reserved.

A series of highly potent and selective PPARdelta agonists is described using the known non-selective ligand GW2433 as a structural template. Compound 1 is bioavailable, potent (10 nM), and shows no cross-activity with other PPAR subtypes up to 10 microM, making it a useful tool in studying the biological effects of selective PPARdelta activation.

A series of PPAR delta-selective agonists was investigated and optimized for a favorable in vivo pharmacokinetic profile. Isoxazole LC1765 (17d) was found to be a potent and selective PPAR delta agonist with good in vivo PK properties in mouse (C-max = 5.1 mu M, t(1/2) = 3.1 h). LC1765 regulated expression of genes involved in energy homeostasis in relevant tissues when dosed orally in C57BL6 mice. A co-crystal structure of compound LC1765 and the LBD of PPAR delta is discussed. (c) 2006 Elsevier Ltd. All rights reserved.