Mitigation of reactive metabolite formation for a series of 3-amino-2-pyridone inhibitors of Bruton's tyrosine kinase (BTK).

Reactive metabolites have been putatively linked to many adverse drug reactions including idiosyncratic toxicities for a number of drugs with black box warnings or withdrawn from the market. Therefore, it is desirable to minimize the risk of reactive metabolite formation for lead molecules in optimization, in particular for non-life threatening chronic disease, to maximize benefit to risk ratio. This article describes our effort in addressing reactive metabolite issues for a series of 3-amino-2-pyridone inhibitors of BTK, e.g. compound 1 has a value of 459pmol/mg protein in the microsomal covalent binding assay. Parallel approaches were taken to successfully resolve the issues: establishment of a predictive screening assay with correlation association of covalent binding assay, identification of the origin of reactive metabolite formation using MS/MS analysis of HLM as well as isolation and characterization of GSH adducts. This ultimately led to the discovery of compound 7 (RN941) with significantly reduced covalent binding of 26pmol/mg protein.

Finding the perfect spot for fluorine: improving potency up to 40-fold during a rational fluorine scan of a Bruton's Tyrosine Kinase (BTK) inhibitor scaffold.

A rational fluorine scan based on co-crystal structures was explored to increase the potency of a series of selective BTK inhibitors. While fluorine substitution on a saturated bicyclic ring system yields no apparent benefit, the same operation on an unsaturated bicyclic ring can increase HWB activity by up to 40-fold. Comparison of co-crystal structures of parent molecules and fluorinated counterparts revealed the importance of placing fluorine at the optimal position to achieve favorable interactions with protein side chains.

Structure-Guided Discovery of cis-Hexahydro-pyrido-oxazinones as Reversible, Drug-like Monoacylglycerol Lipase Inhibitors.

Monoacylglycerol lipase (MAGL) is a key enzyme involved in the metabolism of the endogenous signaling ligand 2-arachidonoylglycerol, a neuroprotective endocannabinoid intimately linked to central nervous system (CNS) disorders associated with neuroinflammation. In the quest for novel MAGL inhibitors, a focused screening approach on a Roche library subset provided a reversible benzoxazinone hit exhibiting high ligand efficiency. The subsequent design of the three-dimensional cis-hexahydro-pyrido-oxazinone (cis-HHPO) moiety as benzoxazinone replacement enabled the combination of high MAGL potency with favorable ADME properties. Through enzymatic resolution an efficient synthetic route of the privileged cis-(4R,8S) HHPO headgroup was established, providing access to the highly potent and selective MAGL inhibitor 7o. Candidate molecule 7o matches the target compound profile of CNS drugs as it achieves high CSF exposures after systemic administration in rodents. It engages with the target in the brain and modulates neuroinflammatory processes, thus holding great promise for the treatment of CNS disorders.

Discovery of carmegliptin: a potent and long-acting dipeptidyl peptidase IV inhibitor for the treatment of type 2 diabetes.

Design, synthesis, and SAR are described for a class of DPP-IV inhibitors based on aminobenzo[a]quinolizines with non-aromatic substituents in the S1 specificity pocket. One representative thereof, carmegliptin (8p), was chosen for clinical development. Its X-ray structure in complex with the enzyme and early efficacy data in animal models of type 2 diabetes are also presented.

DNA-Encoded Library-Derived DDR1 Inhibitor Prevents Fibrosis and Renal Function Loss in a Genetic Mouse Model of Alport Syndrome.

The importance of Discoidin Domain Receptor 1 (DDR1) in renal fibrosis has been shown via gene knockout and use of antisense oligonucleotides; however, these techniques act via a reduction of DDR1 protein, while we prove the therapeutic potential of inhibiting DDR1 phosphorylation with a small molecule. To date, efforts to generate a selective small-molecule to specifically modulate the activity of DDR1 in an in vivo model have been unsuccessful. We performed parallel DNA encoded library screens against DDR1 and DDR2, and discovered a chemical series that is highly selective for DDR1 over DDR2. Structure-guided optimization efforts yielded the potent DDR1 inhibitor 2.45, which possesses excellent kinome selectivity (including 64-fold selectivity over DDR2 in a biochemical assay), a clean in vitro safety profile, and favorable pharmacokinetic and physicochemical properties. As desired, compound 2.45 modulates DDR1 phosphorylation in vitro as well as prevents collagen-induced activation of renal epithelial cells expressing DDR1. Compound 2.45 preserves renal function and reduces tissue damage in Col4a3-/- mice (the preclinical mouse model of Alport syndrome) when employing a therapeutic dosing regime, indicating the real therapeutic value of selectively inhibiting DDR1 phosphorylation in vivo. Our results may have wider significance as Col4a3-/- mice also represent a model for chronic kidney disease, a disease which affects 10% of the global population.

Discovery and Pre-Clinical Characterization of Third-Generation 4-H Heteroaryldihydropyrimidine (HAP) Analogues as Hepatitis B Virus (HBV) Capsid Inhibitors.

Described herein are the discovery and structure-activity relationship (SAR) studies of the third-generation 4-H heteroaryldihydropyrimidines (4-H HAPs) featuring the introduction of a C6 carboxyl group as novel HBV capsid inhibitors. This new series of 4-H HAPs showed improved anti-HBV activity and better drug-like properties compared to the first- and second-generation 4-H HAPs. X-ray crystallographic study of analogue 12 (HAP_R01) with Cp149 Y132A mutant hexamer clearly elucidated the role of C6 carboxyl group played for the increased binding affinity, which formed strong hydrogen bonding interactions with capsid protein and coordinated waters. The representative analogue 10 (HAP_R10) was extensively characterized in vitro (ADMET) and in vivo (mouse PK and PD) and subsequently selected for further development as oral anti-HBV infection agent.

Structure-based drug design of RN486, a potent and selective Bruton's tyrosine kinase (BTK) inhibitor, for the treatment of rheumatoid arthritis.

Structure-based drug design was used to guide the optimization of a series of selective BTK inhibitors as potential treatments for Rheumatoid arthritis. Highlights include the introduction of a benzyl alcohol group and a fluorine substitution, each of which resulted in over 10-fold increase in activity. Concurrent optimization of drug-like properties led to compound 1 (RN486) ( J. Pharmacol. Exp. Ther. 2012 , 341 , 90 ), which was selected for advanced preclinical characterization based on its favorable properties.