Discovery and Preclinical Characterization of BIIB129, a Covalent, Selective, and Brain-Penetrant BTK Inhibitor for the Treatment of Multiple Sclerosis.

Multiple sclerosis (MS) is a chronic disease with an underlying pathology characterized by inflammation-driven neuronal loss, axonal injury, and demyelination. Bruton's tyrosine kinase (BTK), a nonreceptor tyrosine kinase and member of the TEC family of kinases, is involved in the regulation, migration, and functional activation of B cells and myeloid cells in the periphery and the central nervous system (CNS), cell types which are deemed central to the pathology contributing to disease progression in MS patients. Herein, we describe the discovery of BIIB129 (25), a structurally distinct and brain-penetrant targeted covalent inhibitor (TCI) of BTK with an unprecedented binding mode responsible for its high kinome selectivity. BIIB129 (25) demonstrated efficacy in disease-relevant preclinical in vivo models of B cell proliferation in the CNS, exhibits a favorable safety profile suitable for clinical development as an immunomodulating therapy for MS, and has a low projected total human daily dose.

Elucidation of the GSK3α Structure Informs the Design of Novel, Paralog-Selective Inhibitors.

Glycogen synthase kinase 3 (GSK3) remains a therapeutic target of interest for diverse clinical indications. However, one hurdle in the development of small molecule GSK3 inhibitors has been safety concerns related to pan-inhibition of both GSK3 paralogs, leading to activation of the Wnt/ß-catenin pathway and potential for aberrant cell proliferation. Development of GSK3α or GSK3ß paralog-selective inhibitors that could offer an improved safety profile has been reported but further advancement has been hampered by the lack of structural information for GSK3α. Here we report for the first time the crystal structure for GSK3α, both in apo form and bound to a paralog-selective inhibitor. Taking advantage of this new structural information, we describe the design and in vitro testing of novel compounds with up to ∼37-fold selectivity for GSK3α over GSK3ß with favorable drug-like properties. Furthermore, using chemoproteomics, we confirm that acute inhibition of GSK3α can lower tau phosphorylation at disease-relevant sites in vivo, with a high degree of selectivity over GSK3ß and other kinases. Altogether, our studies advance prior efforts to develop GSK3 inhibitors by describing GSK3α structure and novel GSK3α inhibitors with improved selectivity, potency, and activity in disease-relevant systems.

Design, synthesis and identification of novel, orally bioavailable non-covalent Nrf2 activators.

Nrf2 is a transcription factor regulating expression of the Phase II Antioxidant Response and plays an important role in neuroprotection and detoxification. Nrf2 activation is inhibited by interaction with Keap1. Covalent Keap1 inhibitors such as dimethyl fumarate (DMF) and RTA-408 are either on the market or in late stage clinical trials which implies potential benefit of Nrf2 activation. Activation of Nrf2 by disrupting Nrf2-Keap1 interaction through a non-covalent small molecule is an attractive approach with the promise of greater selectivity. However, there are no known non-covalent Nrf2 activators with acceptable pharmacokinetic properties to test the hypothesis in vivo. Based on our early reported work, using structural-based design, followed by extensive SAR exploration, we have identified a novel series of non-covalent Nrf2 activators, with sub-nanomolar binding affinity on Keap1 and single digit nanomolar activity in an astrocyte assay. A representative analog shows excellent oral PK and good Nrf2-dependent gene inductions in kidney. These results provide a peripheral in vivo tool compound to validate the biology of non-covalent activation of Nrf2.

CDK12-mediated transcriptional regulation of noncanonical NF-κB components is essential for signaling.

Members of the family of nuclear factor κB (NF-κB) transcription factors are critical for multiple cellular processes, including regulating innate and adaptive immune responses, cell proliferation, and cell survival. Canonical NF-κB complexes are retained in the cytoplasm by the inhibitory protein IκBα, whereas noncanonical NF-κB complexes are retained by p100. Although activation of canonical NF-κB signaling through the IκBα kinase complex is well studied, few regulators of the NF-κB-inducing kinase (NIK)-dependent processing of noncanonical p100 to p52 and the subsequent nuclear translocation of p52 have been identified. We discovered a role for cyclin-dependent kinase 12 (CDK12) in transcriptionally regulating the noncanonical NF-κB pathway. High-content phenotypic screening identified the compound 919278 as a specific inhibitor of the lymphotoxin ß receptor (LTßR), and tumor necrosis factor (TNF) receptor superfamily member 12A (FN14)-dependent nuclear translocation of p52, but not of the TNF-α receptor-mediated nuclear translocation of p65. Chemoproteomics identified CDK12 as the target of 919278. CDK12 inhibition by 919278, the CDK inhibitor THZ1, or siRNA-mediated knockdown resulted in similar global transcriptional changes and prevented the LTßR- and FN14-dependent expression of MAP3K14 (which encodes NIK) as well as NIK accumulation by reducing phosphorylation of the carboxyl-terminal domain of RNA polymerase II. By coupling a phenotypic screen with chemoproteomics, we identified a pathway for the activation of the noncanonical NF-κB pathway that could serve as a therapeutic target in autoimmunity and cancer.

Direct, enantioselective α-alkylation of aldehydes using simple olefins.

Although the α-alkylation of ketones has already been established, the analogous reaction using aldehyde substrates has proven surprisingly elusive. Despite the structural similarities between the two classes of compounds, the sensitivity and unique reactivity of the aldehyde functionality has typically required activated substrates or specialized additives. Here, we show that the synergistic merger of three catalytic processes-photoredox, enamine and hydrogen-atom transfer (HAT) catalysis-enables an enantioselective α-aldehyde alkylation reaction that employs simple olefins as coupling partners. Chiral imidazolidinones or prolinols, in combination with a thiophenol, iridium photoredox catalyst and visible light, have been successfully used in a triple catalytic process that is temporally sequenced to deliver a new hydrogen and electron-borrowing mechanism. This multicatalytic process enables both intra- and intermolecular aldehyde α-methylene coupling with olefins to construct both cyclic and acyclic products, respectively. With respect to atom and step-economy ideals, this stereoselective process allows the production of high-value molecules from feedstock chemicals in one step while consuming only photons.

Efficient chiral monophosphorus ligands for asymmetric Suzuki-Miyaura coupling reactions.

A series of novel P-chiral monophosphorus ligands exhibit efficiency in asymmetric Suzuki-Miyaura coupling reactions, enabling the construction of an array of chiral biaryl products in high yields and excellent enantioselectivities (up to 96% ee) under mild conditions. The carbonyl-benzooxazolidinone moiety in these chiral biaryl products allows facile derivatization for further synthetic applications. A computational study has revealed that a π-π interaction between the two coupling partners can enhance the enantioselectivity of the coupling reaction.

Diastereoselective intramolecular Friedel-Crafts alkylation of tetralins.

An efficient and versatile synthesis of cis-hexahydrobenzophenanthridines starting from readily available tetralins has been developed using an intramolecular Friedel-Crafts alkylation as a key step. The substrates were prepared via a highly stereocontrolled rhodium-catalyzed ring-opening reaction of meso-oxabicyclic alkenes and a hydrogenation sequence. Thus, a wide variety of complex tetracyclic compounds have been isolated with a high level of regio-, diastereo-, and enantioselectivity.

Copper catalyzed asymmetric propargylation of aldehydes.

The highly enantio- and regioselective copper catalyzed asymmetric propargylation of aldehydes with a propargyl borolane reagent is reported. The methodology demonstrated broad functional group tolerance and provided high enantioselectivities for aliphatic, vinyl, and aryl aldehydes. The utility of the TMS homopropargylic alcohols was demonstrated by the facile conversion to a chiral dihydropyranone.

Novel and efficient chiral bisphosphorus ligands for rhodium-catalyzed asymmetric hydrogenation.

A series of structurally novel, operationally convenient, and efficient chiral 2-phosphino-2,3-dihydrobenzo[d][1,3]oxaphosphole ligands was developed. Applications of ligands 3a and 3b in rhodium-catalyzed asymmetric hydrogenation of alpha-(acylamino)acrylates and beta-(acylamino)acrylates provided excellent enantioselectivities (up to >99% ee) and reactivities (up to 10,000 TON).

Novel, tunable, and efficient chiral bisdihydrobenzooxaphosphole ligands for asymmetric hydrogenation.

A series of novel, efficient, air-stable, and tunable chiral bisdihydrobenzooxaphosphole ligands (BIBOPs) were developed for rhodium-catalyzed hydrogenations of various functionalized olefins such as alpha-arylenamides, alpha-(acylamino)acrylic acid derivatives, beta-(acylamino)acrylates, and dimethyl itaconate with excellent enantioselectivities (up to 99% ee) and reactivities (up to 2000 TON).

A facile and practical synthesis of N-acetyl enamides.

A facile and practical method for the synthesis of N-acetyl alpha-arylenamides has been developed from corresponding ketoximes as the starting materials with ferrous acetate as the reducing reagent. This methodology offers mild reaction conditions, simple purification procedures, and high yields for a variety of N-acetyl enamides.