Pyridones as Highly Selective, Noncovalent Inhibitors of T790M Double Mutants of EGFR

The rapid advancement of a series of noncovalent inhibitors of T790M mutants of EGFR is discussed. The optimization of pyridone <b>1</b>, a nonselective high-throughput screening hit, to potent molecules with high levels of selectivity over wtEGFR and the broader kinome is described herein

Discovery of a Noncovalent, Mutant-Selective Epidermal Growth Factor Receptor Inhibitor

Inhibitors targeting the activating mutants of the epidermal growth factor receptor (EGFR) have found success in the treatment of EGFR mutant positive non-small-cell lung cancer. A secondary point mutation (T790M) in the inhibitor binding site has been linked to the acquired resistance against those first generation therapeutics. Herein, we describe the lead optimization of a series of reversible, pan-mutant (L858R, del_746–750, T790M/L858R, and T790M/del_746–750) EGFR inhibitors. By use of a noncovalent double mutant (T790M/L858R and T790M/del_746–750) selective EGFR inhibitor (<b>2</b>) as a starting point, activities against the single mutants (L858R and del_746–750) were introduced through a series of structure-guided modifications. The in vitro ADME-PK properties of the lead molecules were further optimized through a number of rational structural changes. The resulting inhibitor (<b>21</b>) exhibited excellent cellular activity against both the single and double mutants of EGFR, demonstrating target engagement in vivo and ADME-PK properties that are suitable for further evaluation. The reversible, noncovalent inhibitors described complement the covalent pan-mutant EGFR inhibitors that have shown encouraging results in recent clinical trials

Discovery of 7‑Tetrahydropyran-2-yl Chromans: β‑Site Amyloid Precursor Protein Cleaving Enzyme 1 (BACE1) Inhibitors That Reduce Amyloid β‑Protein (Aβ) in the Central Nervous System

In an attempt to increase selectivity vs Cathepsin D (CatD) in our BACE1 program, a series of 1,3,4,4a,10,10a-hexahydropyrano­[4,3-b]­chromene analogues was developed. Three different Asp-binding moieties were examined: spirocyclic acyl guanidines, aminooxazolines, and aminothiazolines in order to modulate potency, selectivity, efflux, and permeability. Using structure-based design, substitutions to improve binding to both the S3 and S2′ sites of BACE1 were explored. An acyl guanidine moiety provided the most potent analogues. These compounds demonstrated 10–420 fold selectivity for BACE1 vs CatD, and were highly potent in a cell assay measuring Aβ_1–40 production (5–99 nM). They also suffered from high efflux. Despite this undesirable property, two of the acyl guanidines achieved free brain concentrations (C_free,brain) in a guinea pig PD model sufficient to cover their cell IC₅₀s. Moreover, a significant reduction of Aβ_1–40 in guinea pig, rat, and cyno CSF (58%, 53%, and 63%, respectively) was observed for compound <b>62</b>

Cell Active Hydroxylactam Inhibitors of Human Lactate Dehydrogenase with Oral Bioavailability in Mice

A series of trisubstituted hydroxylactams was identified as potent enzymatic and cellular inhibitors of human lactate dehydrogenase A. Utilizing structure-based design and physical property optimization, multiple inhibitors were discovered with <10 μM lactate IC₅₀ in a MiaPaca2 cell line. Optimization of the series led to <b>29</b>, a potent cell active molecule (MiaPaca2 IC₅₀ = 0.67 μM) that also possessed good exposure when dosed orally to mice

Discovery of a Potent and Selective BCL‑X_L Inhibitor with <i>in Vivo</i> Activity

A-1155463, a highly potent and selective BCL-X_L inhibitor, was discovered through nuclear magnetic resonance (NMR) fragment screening and structure-based design. This compound is substantially more potent against BCL-X_L-dependent cell lines relative to our recently reported inhibitor, WEHI-539, while possessing none of its inherent pharmaceutical liabilities. A-1155463 caused a mechanism-based and reversible thrombocytopenia in mice and inhibited H146 small cell lung cancer xenograft tumor growth <i>in vivo</i> following multiple doses. A-1155463 thus represents an excellent tool molecule for studying BCL-X_L biology as well as a productive lead structure for further optimization