Discovery and SAR of JTE-151: A Novel RORγ Inhibitor for Clinical Development.

A number of RORγ inhibitors have been reported over the past decade. There were also several examples advancing to human clinical trials, however, none of them has reached the market yet, suggesting that there could be common obstacles for their future development. As was expected from the general homology of nuclear receptor ligands, insufficient selectivity as well as poor physicochemical properties were identified as potential risks for a RORγ program. Based on such considerations, we conducted a SAR investigation by prioritizing drug-like properties to mitigate such potential drawbacks. After an intensive SAR exploration with strong emphasis on "drug-likeness" indices, an orally available RORγ inhibitor, JTE-151, was finally generated and was advanced to a human clinical trial. The compound was confirmed to possess highly selective profiles along with good metabolic stability, and most beneficially, no serious adverse events (SAE) and good PK profiles were observed in the human clinical trial.

Discovery of Second Generation RORγ Inhibitors Composed of an Azole Scaffold.

Starting from a previously reported RORγ inhibitor (1), successive efforts to improve in vivo potency were continued. Introduction of metabolically beneficial motifs in conjunction with scaffold hopping was examined, resulting in discovery of the second generation RORγ inhibitor composed of a 4-(isoxazol-3-yl)butanoic acid scaffold (24). Compound 24 achieved a 10-fold improvement in in vivo potency in a mouse CD3 challenge model along with significant anti-inflammatory effects in a mouse dermatitis model.

Concise SAR Exploration Based on the "Head-to-Tail" Approach: Discovery of PI4KIIIα Inhibitors Bearing Diverse Scaffolds.

In typical kinase inhibitor programs, a hinge binder showing best potency with preferential specificity is initially selected, followed by fine-tuning of the accompanying substituents on its core module. A shortcoming of this approach is that the exclusive focus on a single chemotype can endanger all the analogues in the series if a critical shortcoming is revealed. Thus, an early evaluation of structure-activity relationships (SARs) can mitigate unforeseen outcomes within a series of multiple compounds, although there have been very few examples to follow such a policy. PI4KIIIα is one of four mammalian phosphatidylinositol-4 kinases and has recently drawn significant attention as an emerging target for hepatitis C virus (HCV) treatment. In this letter, a novel "head-to-tail" approach to discover a diverse set of PI4KIIIα inhibitors is reported. We believe this method will generate distinct core scaffolds, a rational strategy to circumvent potential risks in general kinase programs.

SAR Exploration Guided by LE and Fsp(3): Discovery of a Selective and Orally Efficacious RORγ Inhibitor.

A novel series of RORγ inhibitors was identified starting with the HTS hit 1. After SAR investigation based on a prospective consideration of two drug-likeness metrics, ligand efficiency (LE) and fraction of sp(3) carbon atoms (Fsp(3)), significant improvement of metabolic stability as well as reduction of CYP inhibition was observed, which finally led to discovery of a selective and orally efficacious RORγ inhibitor 3z.

Total synthesis and biological activities of (+)-sulfamisterin (AB5366) and its analogues.

The first total synthesis of (+)-sulfamisterin (AB5366), a naturally occurring alpha-substituted alpha-amino acid derivative possessing a sulfonated hydroxy function, is described. Overman rearrangement of an allylic trichloroacetimidate derived from D-tartrate effectively generated the tetrasubstituted carbon containing a nitrogen substituent. Construction of the amino acid moiety and sulfonation of the hydroxy group, followed by deprotection completed the total synthesis, which fully confirmed the proposed absolute structure of the natural product. The possible stereoisomers of (+)-sulfamisterin and their desulfonated derivatives were also synthesized. Biological assessment of all synthetic compounds revealed that natural (+)-sulfamisterin and its 3-epimer as well as their desulfonated derivatives possessing 2S-configuration strongly inhibit the serine palmitoyl transferase both in vitro and in vivo, whereas compounds with 2R-configuration were found to show much weaker inhibitory activity.