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Bruton's tyrosine kinase (BTK) plays an essential role in multiple cell types responsible for numerous autoimmune diseases, thus inhibition of BTK is anticipated to provide an effective strategy for the clinical treatment of autoimmune diseases. Preparative-scale super/subcritical fluid chromatography (SFC) separation methods for four groups of highly potent and selective BTK inhibitor atropisomers were successfully developed. Depending on the rotation barrier around the chiral axis, the compounds were prepared as a single stereochemically stable atropisomer or as an atropisomeric mixture. Among the four, compound 2 with one rotationally stable atropisomeric center (carbazole/quinazolinedione based) was resolved as a mixture of two atropisomers, while compound 3 (carbazole-chlorine/quinazolinedione based) and 4 (tetrahydrocarbazole-fluorine/quinazolinedione based) with two rotationally stable atropisomeric centers were resolved into a single stable atropisomer. This article discusses the challenges and strategies in preparing large quantities of these atropisomeric active pharmaceutical ingredients (APIs) in support of the BTK program discovery efforts.

[Image: see text] Bruton’s tyrosine kinase (BTK) has been shown to play a key role in the pathogenesis of autoimmunity. Therefore, the inhibition of the kinase activity of BTK with a small molecule inhibitor could offer a breakthrough in the clinical treatment of many autoimmune diseases. This Letter describes the discovery of BMS-986143 through systematic structure–activity relationship (SAR) development. This compound benefits from defined chirality derived from two rotationally stable atropisomeric axes, providing a potent and selective single atropisomer with desirable efficacy and tolerability profiles.

Protein kinases are intensely studied mediators of cellular signaling. While traditional biochemical screens are capable of identifying compounds that modulate kinase activity, these assays are limited in their capability of predicting compound behavior in a cellular environment. Here, we aim to bridge target engagement and compound-cellular phenotypic behavior by utilizing a bioluminescence resonance energy transfer (BRET) assay to characterize target occupancy within living cells for Bruton's tyrosine kinase (BTK). Using a diverse chemical set of BTK inhibitors, we determine intracellular engagement affinity profiles and successfully correlate these measurements with BTK cellular functional readouts. In addition, we leveraged the kinetic capability of this technology to gain insight into in-cell target residence time and the duration of target engagement, and to explore a structural hypothesis.

Bruton’s tyrosine kinase (BTK), a non-receptor tyrosine kinase, is a member of the Tec family of kinases and is essential for B cell receptor (BCR) mediated signaling. BTK also plays a critical role in the downstream signaling pathways for the Fcγ receptor in monocytes, the Fce receptor in granulocytes, and the RANK receptor in osteoclasts. As a result, pharmacological inhibition of BTK is anticipated to provide an effective strategy for the clinical treatment of autoimmune diseases such as rheumatoid arthritis and lupus. This article will outline the evolution of our strategy to identify a covalent, irreversible inhibitor of BTK that has the intrinsic potency, selectivity, and pharmacokinetic properties necessary to provide a rapid rate of inactivation systemically following a very low dose. With excellent in vivo efficacy and a very desirable tolerability profile, 5a (branebrutinib, BMS-986195) has advanced into clinical studies.

Bruton's tyrosine kinase (BTK), a nonreceptor tyrosine kinase, is a member of the Tec family of kinases. BTK plays an essential role in B cell receptor (BCR)-mediated signaling as well as Fcγ receptor signaling in monocytes and Fce receptor signaling in mast cells and basophils, all of which have been implicated in the pathophysiology of autoimmune disease. As a result, inhibition of BTK is anticipated to provide an effective strategy for the clinical treatment of autoimmune diseases such as lupus and rheumatoid arthritis. This article details the structure–activity relationships (SAR) leading to a novel series of highly potent and selective carbazole and tetrahydrocarbazole based, reversible inhibitors of BTK. Of particular interest is that two atropisomeric centers were rotationally locked to provide a single, stable atropisomer, resulting in enhanced potency and selectivity as well as a reduction in safety liabilities. With significantly enhanced potency and selectivity, excellent in vivo properties an...

Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid metabolite that regulates a multitude of physiological processes such as lymphocyte trafficking, cardiac function, vascular development, and inflammation. Because of the ability of S1P1 receptor agonists to suppress lymphocyte egress, they have great potential as therapeutic agents in a variety of autoimmune diseases. In this article, the discovery of selective, direct acting S1P1 agonists utilizing an ethanolamine scaffold containing a terminal carboxylic acid is described. Potent S1P1 agonists such as compounds 18a and 19a which have greater than 1000-fold selectivity over S1P3 are described. These compounds efficiently reduce blood lymphocyte counts in rats through 24 h after single doses of 1 and 0.3 mpk, respectively. Pharmacodynamic properties of both compounds are discussed. Compound 19a was further studied in two preclinical models of disease, exhibiting good efficacy in both the rat adjuvant arthritis model (AA) and the mouse experimental autoimmune encephalomyelitis model (EAE).

This article reports an efficient scale-up synthesis of 1-(4-(5-(3-phenyl-4-(trifluoromethyl)isoxazol-5-yl)-1,2,4-oxadiazol-3-yl)benzyl)azetidine-3-carboxylic acid (BMS-520), a potent and selective isoxazole-containing S1P1 receptor agonist. This process features a highly regioselective cycloaddition leading to a key intermediate, ethyl 3-phenyl-4-(trifluoromethyl)isoxazole-5-carboxylate, a chemo-selective hydrolysis of its regioisomers, as well as an improved method for 1,2,4-oxadiazole formation, relative to the original synthesis. The improved process was applied to the preparation of multiple batches of BMS-520 for preclinical toxicological studies.

Bruton’s tyrosine kinase (BTK) regulates critical signal transduction pathways involved in the pathobiology of rheumatoid arthritis (RA) and other autoimmune disorders. BMS-986142 is a potent and highly selective reversible small molecule inhibitor of BTK currently being investigated in clinical trials for the treatment of both RA and primary Sjogren’s syndrome. In the present report, we detail the in vitro and in vivo pharmacology of BMS-986142 and show this agent provides potent and selective inhibition of BTK (IC50 = 0.5 nM), blocks antigen receptor-dependent signaling and functional endpoints (cytokine production, co-stimulatory molecule expression, and proliferation) in human B cells (IC50 ≤ 5 nM), inhibits Fcγ receptor-dependent cytokine production from peripheral blood mononuclear cells, and blocks RANK-L-induced osteoclastogenesis. Through the benefits of impacting these important drivers of autoimmunity, BMS-986142 demonstrated robust efficacy in murine models of rheumatoid arthritis (RA), including collagen-induced arthritis (CIA) and collagen antibody-induced arthritis (CAIA). In both models, robust efficacy was observed without continuous, complete inhibition of BTK. When a suboptimal dose of BMS-986142 was combined with other agents representing the current standard of care for RA (e.g., methotrexate, the TNFα antagonist etanercept, or the murine form of CTLA4-Ig) in the CIA model, improved efficacy compared to either agent alone was observed. The results suggest BMS-986142 represents a potential therapeutic for clinical investigation in RA, as monotherapy or co-administered with agents with complementary mechanisms of action.

PI3Kδ plays an important role controlling immune cell function and has therefore been identified as a potential target for the treatment of immunological disorders. This article highlights our work toward the identification of a potent, selective, and efficacious PI3Kδ inhibitor. Through careful SAR, the successful replacement of a polar pyrazole group by a simple chloro or trifluoromethyl group led to improved Caco-2 permeability, reduced Caco-2 efflux, reduced hERG PC activity, and increased selectivity profile while maintaining potency in the CD69 hWB assay. The optimization of the aryl substitution then identified a 4′-CN group that improved the human/rodent correlation in microsomal metabolic stability. Our lead molecule is very potent in PK/PD assays and highly efficacious in a mouse collagen-induced arthritis model.

Fingolimod (1) is the first approved oral therapy for the treatment of relapsing remitting multiple sclerosis. While the phosphorylated metabolite of fingolimod was found to be a nonselective S1P receptor agonist, agonism specifically of S1P

Sphingosine 1-phosphate (S1P) is the endogenous ligand for the sphingosine 1-phosphate receptors (S1P1–5) and evokes a variety of cellular responses through their stimulation. The interaction of S1P with the S1P receptors plays a fundamental physiological role in a number of processes including vascular development and stabilization, lymphocyte migration, and proliferation. Agonism of S1P1, in particular, has been shown to play a significant role in lymphocyte trafficking from the thymus and secondary lymphoid organs, resulting in immunosuppression. This article will detail the discovery and SAR of a potent and selective series of isoxazole based full agonists of S1P1. Isoxazole 6d demonstrated impressive efficacy when administered orally in a rat model of arthritis and in a mouse experimental autoimmune encephalomyelitis (EAE) model of multiple sclerosis.

The synthesis and structure–activity relationship (SAR) of a series of pyridyl-isoxazole based agonists of S1P1 are discussed. Compound 5b provided potent in vitro activity with selectivity, had an acceptable pharmacokinetic profile, and demonstrated efficacy in a dose dependent manner when administered orally in a rodent model of arthritis.