ABSTRACT
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.
Subject(s)
Agammaglobulinaemia Tyrosine Kinase , Brain , Multiple Sclerosis , Protein Kinase Inhibitors , Agammaglobulinaemia Tyrosine Kinase/antagonists & inhibitors , Agammaglobulinaemia Tyrosine Kinase/metabolism , Multiple Sclerosis/drug therapy , Humans , Animals , Protein Kinase Inhibitors/pharmacology , Protein Kinase Inhibitors/therapeutic use , Protein Kinase Inhibitors/pharmacokinetics , Protein Kinase Inhibitors/chemistry , Brain/metabolism , Mice , Drug Discovery , Encephalomyelitis, Autoimmune, Experimental/drug therapy , Rats , Structure-Activity Relationship , Cell Proliferation/drug effects , FemaleABSTRACT
Apoptosis signal-regulating kinase 1 (ASK1) is one of the key mediators of the cellular stress response that regulates inflammation and apoptosis. To probe the therapeutic value of modulating this pathway in preclinical models of neurological disease, we further optimized the profile of our previously reported inhibitor 3. This effort led to the discovery of 32, a potent (cell IC50 = 25 nM) and selective ASK1 inhibitor with suitable pharmacokinetic and brain penetration (rat Cl/Clu = 1.6/56 L/h/kg and Kp,uu = 0.46) for proof-of-pharmacology studies. Specifically, the ability of 32 to inhibit ASK1 in the central nervous system (CNS) was evaluated in a human tau transgenic (Tg4510) mouse model exhibiting elevated brain inflammation. In this study, transgenic animals treated with 32 (at 3, 10, and 30 mg/kg, BID/PO for 4 days) showed a robust reduction of inflammatory markers (e.g., IL-1ß) in the cortex, thus confirming inhibition of ASK1 in the CNS.
Subject(s)
Brain/drug effects , Drug Discovery , Inflammation/drug therapy , MAP Kinase Kinase Kinase 5/antagonists & inhibitors , Protein Kinase Inhibitors/pharmacology , Pyrazoles/pharmacology , Animals , Brain/metabolism , Dose-Response Relationship, Drug , Humans , Inflammation/metabolism , MAP Kinase Kinase Kinase 5/metabolism , Mice , Mice, Transgenic , Molecular Structure , Protein Kinase Inhibitors/chemical synthesis , Protein Kinase Inhibitors/chemistry , Pyrazoles/chemical synthesis , Pyrazoles/chemistry , Rats , Structure-Activity RelationshipABSTRACT
Structural analysis of the known NIK inhibitor 3 bound to the kinase domain of TTBK1 led to the design and synthesis of a novel class of azaindazole TTBK1 inhibitors exemplified by 8 (cell IC50: 571 nM). Systematic optimization of this series of analogs led to the discovery of 31, a potent (cell IC50: 315 nM) and selective TTBK inhibitor with suitable CNS penetration (rat Kp,uu: 0.32) for in vivo proof of pharmacology studies. The ability of 31 to inhibit tau phosphorylation at the disease-relevant Ser 422 epitope was demonstrated in both a mouse hypothermia and a rat developmental model and provided evidence that modulation of this target may be relevant in the treatment of Alzheimer's disease and other tauopathies.
Subject(s)
Brain/metabolism , Drug Design , Protein Kinase Inhibitors/metabolism , Protein Kinase Inhibitors/pharmacology , Protein Serine-Threonine Kinases/antagonists & inhibitors , tau Proteins/metabolism , Animals , Humans , Indazoles/chemistry , Indazoles/metabolism , Indazoles/pharmacology , Mice , Molecular Targeted Therapy , Phosphorylation/drug effects , Protein Kinase Inhibitors/chemistry , RatsABSTRACT
Apoptosis signal-regulating kinase 1 (ASK1) is a key mediator in the apoptotic and inflammatory cellular stress response. To investigate the therapeutic value of modulating this pathway in neurological disease, we have completed medicinal chemistry studies to identify novel CNS-penetrant ASK1 inhibitors starting from peripherally restricted compounds reported in the literature. This effort led to the discovery of 21, a novel ASK1 inhibitor with good potency (cell IC50 = 138 nM), low clearance (rat Cl/Clu = 0.36/6.7 L h-1 kg-1) and good CNS penetration (rat K p,uu = 0.38).
ABSTRACT
Structural analysis of a known apoptosis signal-regulating kinase 1 (ASK1) inhibitor bound to its kinase domain led to the design and synthesis of the novel macrocyclic inhibitor 8 (cell IC50 = 1.2 µM). The profile of this compound was optimized for CNS penetration following two independent strategies: a rational design approach leading to 19 and a parallel synthesis approach leading to 26. Both analogs are potent ASK1 inhibitors in biochemical and cellular assays (19, cell IC50 = 95 nM; 26, cell IC50 = 123 nM) and have moderate to low efflux ratio (ER) in an MDR1-MDCK assay (19, ER = 5.2; 26, ER = 1.5). In vivo PK studies revealed that inhibitor 19 had moderate CNS penetration (Kpuu = 0.17) and analog 26 had high CNS penetration (Kpuu = 1.0).