A total synthesis of N-desmethyl thalassospiramide C, a unique strained macrocyclic proteobacterial depsipeptide, enabled a detailed crystallographic study of its covalent complex with cathepsin K, a member of a medicinally important family of cysteine proteases. The study provides support for the mechanism of action, and the insight gained can be used for structure-based drug design targeting these calpain proteases.

A hit to lead process to identify reversible, orally available ADP receptor (P2Y(12)) antagonists lead compounds is described. High throughput screening afforded 1. Optimization of 1, using parallel synthesis methods, a methyl scan to identify promising regions for optimization, and exploratory SAR on these regions, provided 22 and 23. Compound 23 is an orally available, competitive reversible antagonist (K-B = 94 nM for inhibition of ADP-induced platelet aggregation). It exhibits high metabolic stability in human, rat and dog liver microsomes and is orally absorbed. Although plasma level after oral dosing of 22 and 23 to rats is low, reasonable levels were achieved to merit extensive lead optimization of this structural class. (C) 2018 Elsevier Ltd. All rights reserved.

We report here the design and synthesis of a novel series of benzylamines that are potent and selective inhibitors of uPA with promising oral availability in rat. Further evaluation of one representative (ZK824859) of the new structural class showed that this compound lowered clinical scores when dosed in either acute or chronic mouse EAE models, suggesting that uPA inhibitors of this type could be useful for the treatment of multiple sclerosis.

The current paradigm for the treatment of chronic hepatitis C virus (HCV) infection involves combinations of agents that act directly on steps of the HCV life cycle. Here we report the preclinical characteristics of ITMN-8187, a nonmacrocyclic inhibitor of the NS3/4A HCV protease. X-ray crystallographic studies of ITMN-8187 and simeprevir binding to NS3/4A protease demonstrated good agreement between structures. Low nanomolar biochemical potency was maintained against NS3/4A derived from HCV genotypes 1, 2b, 4, 5, and 6. In cell-based potency assays, half-maximal reduction of genotype 1a and 1b HCV replicon RNA was afforded by 11 and 4 nM doses of ITMN-8187, respectively. Combinations of ITMN-8187 with other directly acting antiviral agents in vitro displayed additive antiviral efficacy. A 30-mg/kg of body weight dose of ITMN-8187 administered for 4 days yielded significant viral load reductions through day 5 in a chimeric mouse model of HCV. A 3-mg/kg oral dose administered to rats, dogs, or monkeys yielded concentrations in plasma 16 h after dosing that exceeded the half-maximal effective concentration of ITMN-8187. Human microdose pharmacokinetics showed low intersubject variability and prolonged oral absorption with first-order elimination kinetics compatible with once-daily dosing. These preclinical characteristics compare favorably with those of other NS3/4A inhibitors approved for the treatment of chronic HCV infection.

HCV serine protease NS3 represents an attractive drug target because it is not only essential for viral replication but also implicated in the viral evasion of the host immune response pathway through direct cleavage of key proteins in the human innate immune system. Through structure-based drug design and optimization, macrocyclic peptidomimetic molecules bearing both a lipophilic P2 isoindoline carbamate and a P1/P1' acylsulfonamide/acylsulfamide carboxylic acid bioisostere were prepared that possessed subnanomolar potency against the NS3 protease in a subgenomic replicon-based cellular assay (Huh-7). Danoprevir (compound 49) was selected as the clinical development candidate for its favorable potency profile across multiple HCV genotypes and key mutant strains and for its good in vitro ADME profiles and in vivo target tissue (liver) exposures across multiple animal species. X-ray crystallographic studies elucidated several key features in the binding of danoprevir to HCV NS3 protease and proved invaluable to our iterative structure-based design strategy.

Introduction: A lysyl oxidase like 2 (LOXL2) directed monoclonal antibody (simtuzumab) is being clinically evaluated for the treatment of various fibrotic diseases including idiopathic pulmonary fibrosis (IPF). Objective: To characterize small molecule LOXL2 inhibitors biochemically and in functional assays to assess anti-fibrotic activity. Methods: High throughput screening was used to identify small molecule LOXL2 inhibitors. Screening hits were profiled for biochemical inhibition of LOXL2 and closely related amine oxidases (AOs). Binding to LOXL2 was confirmed by surface plasmon resonance (SPR) methods. Mechanistic experiments were used to judge substrate activity, reversibility, and allosteric and/or non-competitive LOXL2 inhibition. A novel collagen cross-linking assay was developed to evaluate the inhibitors. Results: Both reversible and irreversible LOXL2 inhibitors from various chemotypes were identified with biochemical IC50s of 100-fold over monoamine oxidase A and B was achieved. Lead molecules demonstrated low micromolar inhibition of collagen cross-linking. Conclusions: We have identified novel LOXL2 selective small molecule inhibitors, which demonstrate activity in functional assays relevant to fibrosis.

J. Ramphal, J. B. Nicholas, C. Schaefer, H. Ramesha, L. Hooi, A. Arfsten, K. Kossen, D. Ruhrmund, S. Lim, S. Kim, K. Dolim, C. Zhen, M. Hu, J. Henshilwood, R. Radhakrishnan, S. Sastry, K. Emayan, S. Misialek, R. Rajagopalan, L. Pan, L. Huang, S. Yap, S. D. Seiwert, B. O. Buckman InterMune, Inc., Brisbane, CA, USA Background: Pirfenidone is an orally active small molecule antifibrotic agent that has been approved for the treatment of IPF in multiple countries in Europe, Asia, North America and Latin America. Therefore, pirfenidone can be viewed as one of the few clinically validated chemotypes for IPF treatment. Further optimization of the pirfenidone chemotype was undertaken for ADME/PK, efficacy and safety properties. Methods : A library of analogs based on chemical similarity to pirfenidone was designed and screened in anti-fibrotic, cell-based assays. Results : Across animal species, oral dosing of ITMN-14440 provided greater drug exposure at lower relative Cmax than pirfenidone. In a 14-day bleomycin-induced pulmonary fibrosis model with prophylactic dosing, and in a 28-day model with therapeutic dosing, ITMN-14440 had improved efficacy, and anti-fibrotic activity was observed at lower doses and with less frequent dosing when compared to pirfenidone. In a rodent model with potential relevance to the gastrointestinal side effects, ITMN-14440 showed superior performance relative to pirfenidone. Conclusions: Optimized analogs of pirfenidone represent novel chemical entities that may advance the treatment of IPF and other fibrotic conditions. ITMN-14440 displays superior performance relative to pirfenidone in animal models of pulmonary fibrosis and minimal effects in a model of gastrointestinal side effects. The non-clinical pharmacokinetic properties of ITMN-14440 suggest the potential for once or twice daily dosing in humans.