Discovery of LOU064 (Remibrutinib), a Potent and Highly Selective Covalent Inhibitor of Bruton’s Tyrosine Kinase

Daniela Angst, François Gessier, Philipp Janser, Anna Vulpetti, Rudolf Wälchli, Christian Beerli, Amanda Littlewood-Evans, Janet Dawson, Barbara Nuesslein-Hildesheim, Grazyna Wieczorek, Sascha Gutmann, Clemens Scheufler, Alexandra Hinniger, Alfred Gilbert Zimmerlin, Enrico G. Funhoff, Robert Pulz, and Bruno Cenni

J. Med. Chem. 2020
https://doi.org/10.1021/acs.jmedchem.9b01916

Bruton’s tyrosine kinase (BTK), a cytoplasmic tyrosine kinase, plays a central role in immunity and is considered an attractive target for treating autoimmune diseases. The use of currently marketed covalent BTK inhibitors is limited to oncology indications based on their suboptimal kinase selectivity. We describe the discovery and preclinical profile of LOU064 (remibrutinib, 25), a potent, highly selective covalent BTK inhibitor. LOU064 exhibits an exquisite kinase selectivity due to binding to an inactive conformation of BTK and has the potential for a best-in-class covalent BTK inhibitor for the treatment of autoimmune diseases. It demonstrates potent in vivo target occupancy with an EC90 of 1.6 mg/kg and dose-dependent efficacy in rat collagen-induced arthritis. LOU064 is currently being tested in Phase 2 clinical studies for chronic spontaneous urticaria and Sjoegren’s Syndrome.

Designing Chimeric Molecules for Drug Discovery by Leveraging Chemical Biology

Chiara Borsari, Darci J. Trader, Annalisa Tait, and Maria P. Costi
Journal of Medicinal Chemistry 2020
DOI: 10.1021/acs.jmedchem.9b01456

After the first seed concept introduced in the 18th century, different disciplines have attributed different names to dual-functional molecules depending on their application, including bioconjugates, bifunctional compounds, multitargeting molecules, chimeras, hybrids, engineered compounds. However, these engineered constructs share a general structure: a first component that targets a specific cell and a second component that exerts the pharmacological activity. A stable or cleavable linker connects the two modules of a chimera. Herein, we discuss the recent advances in the rapidly expanding field of chimeric molecules leveraging chemical biology concepts. This Perspective is focused on bifunctional compounds in which one component is a lead compound or a drug. In detail, we discuss chemical features of chimeric molecules and their use for targeted delivery and for target engagement studies.

Development of a covalent inhibitor of gut bacterial bile salt hydrolases

Arijit A. Adhikari, Tom C. M. Seegar, Scott B. Ficarro, Megan D. McCurry, Deepti Ramachandran, Lina Yao, Snehal N. Chaudhari, Sula Ndousse-Fetter, Alexander S. Banks, Jarrod A. Marto, Stephen C. Blacklow & A. Sloan Devlin

Nature Chemical Biology (2020)
https://doi.org/10.1038/s41589-020-0467-3

Bile salt hydrolase (BSH) enzymes are widely expressed by human gut bacteria and catalyze the gateway reaction leading to secondary bile acid formation. Bile acids regulate key metabolic and immune processes by binding to host receptors. There is an unmet need for a potent tool to inhibit BSHs across all gut bacteria to study the effects of bile acids on host physiology. Here, we report the development of a covalent pan-inhibitor of gut bacterial BSHs. From a rationally designed candidate library, we identified a lead compound bearing an alpha-fluoromethyl ketone warhead that modifies BSH at the catalytic cysteine residue. This inhibitor abolished BSH activity in conventional mouse feces. Mice gavaged with a single dose of this compound displayed decreased BSH activity and decreased deconjugated bile acid levels in feces. Our studies demonstrate the potential of a covalent BSH inhibitor to modulate bile acid composition in vivo.

Cyclization Reaction-Based Turn-on Probe for Covalent Labeling of Target Proteins

Simon A. Hawley, Fiona A. Ross, Fiona M. Russell, Abdelmadjid Atrih, Douglas J. Lamont, D. Grahame Hardie
Cell Chem. Biol. 2020
DOI: https://doi.org/10.1016/j.chembiol.2020.01.006

Cordycepin (3-deoxyadenosine) is a major bioactive agent in Cordyceps militaris, a fungus used in traditional Chinese medicine. It has been proposed to have many beneficial metabolic effects by activating AMP-activated protein kinase (AMPK), but the mechanism of activation remained uncertain. We report that cordycepin enters cells via adenosine transporters and is converted by cellular metabolism into mono-, di-, and triphosphates, which at high cordycepin concentrations can almost replace cellular adenine nucleotides. AMPK activation by cordycepin in intact cells correlates with the content of cordycepin monophosphate and not other cordycepin or adenine nucleotides. Genetic knockout of AMPK sensitizes cells to the cytotoxic effects of cordycepin. In cell-free assays, cordycepin monophosphate mimics all three effects of AMP on AMPK, while activation in cells is blocked by a γ-subunit mutation that prevents activation by AMP. Thus, cordycepin is a pro-drug that activates AMPK by being converted by cellular metabolism into the AMP analog cordycepin
monophosphate.

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