Identification of LY3522348: A Highly Selective and Orally Efficacious Ketohexokinase Inhibitor.

The identification of clinical candidate LY3522348 (compound 23) is described. LY3522348 is a highly selective, oral dual inhibitor of human ketohexokinase isoforms C and A (hKHK-C, hKHK-A). Optimization began with highly efficient (S)-2-(2-methylazetidin-1-yl)-6-(1H-pyrazol-4-yl)-4-(trifluoromethyl)nicotinonitrile (3). Efforts focused on developing absorption, distribution, metabolism, potency, and in vitro safety profiles to support oral QD dosing in patients. Structure-based design leveraged vectors for substitution of the pyrazole ring, which provided an opportunity to interact with several different proximal amino acid residues in the protein. LY3522348 displayed a robust pharmacodynamic response in a mouse model of fructose metabolism and was advanced into clinical trials.

Structural basis for GPR40 allosteric agonism and incretin stimulation.

Activation of free fatty acid receptor 1 (GPR40) by synthetic partial and full agonists occur via distinct allosteric sites. A crystal structure of GPR40-TAK-875 complex revealed the allosteric site for the partial agonist. Here we report the 2.76-Å crystal structure of human GPR40 in complex with a synthetic full agonist, compound 1, bound to the second allosteric site. Unlike TAK-875, which acts as a Gαq-coupled partial agonist, compound 1 is a dual Gαq and Gαs-coupled full agonist. compound 1 binds in the lipid-rich region of the receptor near intracellular loop 2 (ICL2), in which the stabilization of ICL2 by the ligand is likely the primary mechanism for the enhanced G protein activities. The endogenous free fatty acid (FFA), γ-linolenic acid, can be computationally modeled in this site. Both γ-linolenic acid and compound 1 exhibit positive cooperativity with TAK-875, suggesting that this site could also serve as a FFA binding site.

Discovery of LY3104607: A Potent and Selective G Protein-Coupled Receptor 40 (GPR40) Agonist with Optimized Pharmacokinetic Properties to Support Once Daily Oral Treatment in Patients with Type 2 Diabetes Mellitus.

As a part of our program to identify potent GPR40 agonists capable of being dosed orally once daily in humans, we incorporated fused heterocycles into our recently disclosed spiropiperidine and tetrahydroquinoline acid derivatives 1, 2, and 3 with the intention of lowering clearance and improving the maximum absorbable dose (Dabs). Hypothesis-driven structural modifications focused on moving away from the zwitterion-like structure. and mitigating the N-dealkylation and O-dealkylation issues led to triazolopyridine acid derivatives with unique pharmacology and superior pharmacokinetic properties. Compound 4 (LY3104607) demonstrated functional potency and glucose-dependent insulin secretion (GDIS) in primary islets from rats. Potent, efficacious, and durable dose-dependent reductions in glucose levels were seen during glucose tolerance test (GTT) studies. Low clearance, volume of distribution, and high oral bioavailability were observed in all species. The combination of enhanced pharmacology and pharmacokinetic properties supported further development of this compound as a potential glucose-lowering drug candidate.

The Discovery, Preclinical, and Early Clinical Development of Potent and Selective GPR40 Agonists for the Treatment of Type 2 Diabetes Mellitus (LY2881835, LY2922083, and LY2922470).

The G protein-coupled receptor 40 (GPR40) also known as free fatty acid receptor 1 (FFAR1) is highly expressed in pancreatic, islet ß-cells and responds to endogenous fatty acids, resulting in amplification of insulin secretion only in the presence of elevated glucose levels. Hypothesis driven structural modifications to endogenous FFAs, focused on breaking planarity and reducing lipophilicity, led to the identification of spiropiperidine and tetrahydroquinoline acid derivatives as GPR40 agonists with unique pharmacology, selectivity, and pharmacokinetic properties. Compounds 1 (LY2881835), 2 (LY2922083), and 3 (LY2922470) demonstrated potent, efficacious, and durable dose-dependent reductions in glucose levels along with significant increases in insulin and GLP-1 secretion during preclinical testing. A clinical study with 3 administered to subjects with T2DM provided proof of concept of 3 as a potential glucose-lowering therapy. This manuscript summarizes the scientific rationale, medicinal chemistry, preclinical, and early development data of this new class of GPR40 agonists.

Synthesis, metabolism and in vitro cytotoxicity studies on novel lavendamycin antitumor agents.

A series of lavendamycin analogues with two, three or four substituents at the C-6, C-7 N, C-2', C-3' and C-11' positions were synthesized via short and efficient methods and evaluated as potential NAD(P)H:quinone oxidoreductase (NQO1)-directed antitumor agents. The compounds were prepared through Pictet-Spengler condensation of the desired 2-formylquinoline-5,8-diones with the required tryptophans followed by further needed transformations. Metabolism and toxicity studies demonstrated that the best substrates for NQO1 were also the most selectively toxic to NQO1-rich tumor cells compared to NQO1-deficient tumor cells.

Lavendamycin antitumor agents: structure-based design, synthesis, and NAD(P)H:quinone oxidoreductase 1 (NQO1) model validation with molecular docking and biological studies.

A 1H69 crystal structure-based in silico model of the NAD(P)H:quinone oxidoreductase 1 (NQO1) active site has been developed to facilitate NQO1-directed lavendamycin antitumor agent development. Lavendamycin analogues were designed as NQO1 substrates utilizing structure-based design criteria. Computational docking studies were performed using the model to predict NQO1 substrate specificity. Designed N-acyllavendamycin esters and amides were synthesized by Pictet-Spengler condensation. Metabolism and cytotoxicity studies were performed on the analogues with recombinant human NQO1 and human colon adenocarcinoma cells (NQO1-deficient BE and NQO1-rich BE-NQ). Docking and biological data were found to be correlated where analogues 12, 13, 14, 15, and 16 were categorized as good, poor, poor, poor, and good NQO1 substrates, respectively. Our results demonstrated that the ligand design criteria were valid, resulting in the discovery of two good NQO1 substrates. The observed consistency between the docking and biological data suggests that the model possesses practical predictive power.

Novel lavendamycin analogues as antitumor agents: synthesis, in vitro cytotoxicity, structure-metabolism, and computational molecular modeling studies with NAD(P)H:quinone oxidoreductase 1.

Novel lavendamycin analogues with various substituents were synthesized and evaluated as potential NAD(P)H:quinone oxidoreductase (NQO1)-directed antitumor agents. Pictet-Spengler condensation of quinoline- or quninoline-5,8-dione aldehydes with tryptamine or tryptophans yielded the lavendamycins. Metabolism studies with recombinant human NQO1 revealed that addition of NH2 and CH2OH groups at the quinolinedione-7-position and indolopyridine-2'-position had the greatest positive impact on substrate specificity. The best and poorest substrates were 37 (2'-CH2OH-7-NH2 derivative) and 31 (2'-CONH2-7-NHCOC3H7-n derivative) with reduction rates of 263 +/- 30 and 0.1 +/- 0.1 micromol/min/mg NQO1, respectively. Cytotoxicity toward human colon adenocarcinoma cells was determined for the lavendamycins. The best substrates for NQO1 were also the most selectively toxic to the NQO1-rich BE-NQ cells compared to NQO1-deficient BE-WT cells with 37 as the most selective. Molecular docking supported a model in which the best substrates were capable of efficient hydrogen-bonding interactions with key residues of the active site along with hydride ion reception.