ABSTRACT
The selective inhibition of RET kinase as a treatment for relevant cancer types including lung adenocarcinoma has garnered considerable interest in recent years and prompted a variety of efforts toward the discovery of small-molecule therapeutics. Hits uncovered via the analysis of archival kinase data ultimately led to the identification of a promising pyrrolo[2,3-d]pyrimidine scaffold. The optimization of this pyrrolo[2,3-d]pyrimidine core resulted in compound 1, which demonstrated potent in vitro RET kinase inhibition and robust in vivo efficacy in RET-driven tumor xenografts upon multiday dosing in mice. The administration of 1 was well-tolerated at established efficacious doses (10 and 30 mg/kg, po, qd), and plasma exposure levels indicated a minimal risk of KDR or hERG inhibition in vivo, as evaluated by Miles assay and free plasma concentrations, respectively.
ABSTRACT
RET (REarranged during Transfection) kinase gain-of-function aberrancies have been identified as potential oncogenic drivers in lung adenocarcinoma, along with several other cancer types, prompting the discovery and assessment of selective inhibitors. Internal mining and analysis of relevant kinase data informed the decision to investigate a pyrazolo[1,5-a]pyrimidine scaffold, where subsequent optimization led to the identification of compound WF-47-JS03 (1), a potent RET kinase inhibitor with >500-fold selectivity against KDR (Kinase insert Domain Receptor) in cellular assays. In subsequent mouse in vivo studies, compound 1 demonstrated effective brain penetration and was found to induce strong regression of RET-driven tumor xenografts at a well-tolerated dose (10 mg/kg, po, qd). Higher doses of 1, however, were poorly tolerated in mice, similar to other pyrazolo[1,5-a]pyrimidine compounds at or near the efficacious dose, and indicative of the narrow therapeutic windows seen with this scaffold.
ABSTRACT
Farnesoid X receptor (FXR) agonists are emerging as important potential therapeutics for the treatment of nonalcoholic steatohepatitis (NASH) patients, as they exert positive effects on multiple aspects of the disease. FXR agonists reduce lipid accumulation in the liver, hepatocellular inflammation, hepatic injury, and fibrosis. While there are currently no approved therapies for NASH, the bile acid-derived FXR agonist obeticholic acid (OCA; 6-ethyl chenodeoxycholic acid) has shown promise in clinical studies. Previously, we described the discovery of tropifexor (LJN452), the most potent non-bile acid FXR agonist currently in clinical investigation. Here, we report the discovery of a novel chemical series of non-bile acid FXR agonists based on a tricyclic dihydrochromenopyrazole core from which emerged nidufexor (LMB763), a compound with partial FXR agonistic activity in vitro and FXR-dependent gene modulation in vivo. Nidufexor has advanced to Phase 2 human clinical trials in patients with NASH and diabetic nephropathy.
Subject(s)
Benzothiazoles/therapeutic use , Chenodeoxycholic Acid/analogs & derivatives , Diet, High-Fat/adverse effects , Isoxazoles/therapeutic use , Non-alcoholic Fatty Liver Disease/drug therapy , Receptors, Cytoplasmic and Nuclear/agonists , Animals , Benzothiazoles/chemistry , Chenodeoxycholic Acid/chemistry , Chenodeoxycholic Acid/therapeutic use , Dogs , Humans , Isoxazoles/chemistry , Male , Mice , Mice, Inbred C57BL , Non-alcoholic Fatty Liver Disease/blood , Non-alcoholic Fatty Liver Disease/etiology , Protein Structure, Tertiary , Rats , Treatment OutcomeABSTRACT
Farnesoid X receptor (FXR) agonism is emerging as an important potential therapeutic mechanism of action for multiple chronic liver diseases. The bile acid-derived FXR agonist obeticholic acid (OCA) has shown promise in a phase 2 study in patients with nonalcoholic steatohepatitis (NASH). Here, we report efficacy of the novel nonbile acid FXR agonist tropifexor (LJN452) in two distinct preclinical models of NASH. The efficacy of tropifexor at <1 mg/kg doses was superior to that of OCA at 25 mg/kg in the liver in both NASH models. In a chemical and dietary model of NASH (Stelic animal model [STAM]), tropifexor reversed established fibrosis and reduced the nonalcoholic fatty liver disease activity score and hepatic triglycerides. In an insulin-resistant obese NASH model (amylin liver NASH model [AMLN]), tropifexor markedly reduced steatohepatitis, fibrosis, and profibrogenic gene expression. Transcriptome analysis of livers from AMLN mice revealed 461 differentially expressed genes following tropifexor treatment that included a combination of signatures associated with reduction of oxidative stress, fibrogenesis, and inflammation. Conclusion: Based on preclinical validation in animal models, tropifexor is a promising investigational therapy that is currently under phase 2 development for NASH.
ABSTRACT
The farnesoid X receptor (FXR) is a nuclear receptor that acts as a master regulator of bile acid metabolism and signaling. Activation of FXR inhibits bile acid synthesis and increases bile acid conjugation, transport, and excretion, thereby protecting the liver from the harmful effects of bile accumulation, leading to considerable interest in FXR as a therapeutic target for the treatment of cholestasis and nonalcoholic steatohepatitis. We identified a novel series of highly potent non-bile acid FXR agonists that introduce a bicyclic nortropine-substituted benzothiazole carboxylic acid moiety onto a trisubstituted isoxazole scaffold. Herein, we report the discovery of 1 (tropifexor, LJN452), a novel and highly potent agonist of FXR. Potent in vivo activity was demonstrated in rodent PD models by measuring the induction of FXR target genes in various tissues. Tropifexor has advanced into phase 2 human clinical trials in patients with NASH and PBC.
Subject(s)
Benzothiazoles/pharmacology , Cholestasis/drug therapy , Isoxazoles/pharmacology , Non-alcoholic Fatty Liver Disease/drug therapy , Receptors, Cytoplasmic and Nuclear/agonists , Administration, Oral , Animals , Benzothiazoles/therapeutic use , Biological Availability , Dogs , Drug Evaluation, Preclinical/methods , Fibroblast Growth Factors/genetics , Gene Expression Regulation/drug effects , Humans , Isoxazoles/therapeutic use , Male , Microsomes, Liver/drug effects , Piperidines/chemistry , Rats, Sprague-Dawley , Receptors, Cytoplasmic and Nuclear/genetics , Receptors, Cytoplasmic and Nuclear/metabolism , Structure-Activity Relationship , Triglycerides/bloodABSTRACT
Deregulated kinase activities of tropomyosin receptor kinase (TRK) family members have been shown to be associated with tumorigenesis and poor prognosis in a variety of cancer types. In particular, several chromosomal rearrangements involving TRKA have been reported in colorectal, papillary thyroid, glioblastoma, melanoma, and lung tissue that are believed to be the key oncogenic driver in these tumors. By screening the Novartis compound collection, a novel imidazopyridazine TRK inhibitor was identified that served as a launching point for drug optimization. Structure guided drug design led to the identification of (R)-2-phenylpyrrolidine substituted imidazopyridazines as a series of potent, selective, orally bioavailable pan-TRK inhibitors achieving tumor regression in rats bearing KM12 xenografts. From this work the (R)-2-phenylpyrrolidine has emerged as an ideal moiety to incorporate in bicyclic TRK inhibitors by virtue of its shape complementarity to the hydrophobic pocket of TRKs.
ABSTRACT
The synthesis and SAR studies of a novel N-aryl pyridinone class of p38 kinase inhibitors are described. Systematic structural modifications to the HTS lead, 5, led to the identification of (-)-4a as a clinical candidate for the treatment of inflammatory diseases. Additionally, the chiral synthesis and properties of (-)-4a are described.
Subject(s)
Benzamides/chemical synthesis , Benzamides/pharmacology , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacology , Pyrones/chemical synthesis , Pyrones/pharmacology , p38 Mitogen-Activated Protein Kinases/antagonists & inhibitors , Animals , Benzamides/chemistry , Disease Models, Animal , Dogs , Enzyme Activation/drug effects , Enzyme Inhibitors/chemistry , Humans , Inhibitory Concentration 50 , Macaca fascicularis , Male , Molecular Structure , Pyridones , Pyrones/chemistry , Rats , Rats, Sprague-Dawley , Structure-Activity Relationship , p38 Mitogen-Activated Protein Kinases/chemistry , p38 Mitogen-Activated Protein Kinases/pharmacologyABSTRACT
A series of N-aryl pyridinone inhibitors of p38 mitogen activated protein (MAP) kinase were designed and prepared based on the screening hit SC-25028 (1) and structural comparisons to VX-745 (5). The focus of the investigation targeted the dependence of potency and metabolic stability on the benzyloxy connectivity, the role of the C-6 position and the substitution pattern on the N-phenyl ring. Further optimization produced the highly selective and potent pyridinones 2 and 3. These inhibitors exhibited activity in both acute and chronic models of inflammation.
Subject(s)
Drug Design , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacology , Pyridones/chemical synthesis , Pyridones/pharmacology , p38 Mitogen-Activated Protein Kinases/antagonists & inhibitors , Animals , Disease Models, Animal , Enzyme Activation/drug effects , Enzyme Inhibitors/chemistry , Humans , Inhibitory Concentration 50 , Male , Microsomes, Liver/enzymology , Molecular Structure , Pyridazines/chemistry , Pyridazines/pharmacology , Pyridones/chemistry , Pyrimidines/chemistry , Pyrimidines/pharmacology , Rats , Rats, Sprague-DawleyABSTRACT
The structure based drug design, synthesis and structure-activity relationship of a series of C6 sulfur linked triazolopyridine based p38 inhibitors are described. The metabolic deficiencies of this series were overcome through changes in the C6 linker from sulfur to methylene, which was predicted by molecular modeling to be bioisosteric. X-ray of the ethylene linked compound 61 confirmed the predicted binding orientation of the scaffold in the p38 enzyme.
Subject(s)
Benzamides/chemistry , Bridged Bicyclo Compounds, Heterocyclic/chemistry , Protein Kinase Inhibitors/chemistry , Pyrimidines/chemistry , Triazoles/chemistry , p38 Mitogen-Activated Protein Kinases/antagonists & inhibitors , Animals , Benzamides/chemical synthesis , Benzamides/pharmacology , Binding Sites , Bridged Bicyclo Compounds, Heterocyclic/chemical synthesis , Bridged Bicyclo Compounds, Heterocyclic/pharmacology , Crystallography, X-Ray , Drug Design , Humans , Microsomes, Liver/metabolism , Models, Chemical , Models, Molecular , Protein Kinase Inhibitors/chemical synthesis , Protein Kinase Inhibitors/pharmacology , Pyrimidines/chemical synthesis , Pyrimidines/pharmacology , Rats , Structure-Activity Relationship , Triazoles/chemical synthesis , Triazoles/pharmacology , p38 Mitogen-Activated Protein Kinases/metabolismABSTRACT
The identification and evolution of a series of potent and selective p38 inhibitors is described. p38 inhibitors based on a N-benzyl pyridinone high-throughput screening hit were prepared and their SAR explored. Their design was guided by ligand bound co-crystals of p38alpha. These efforts resulted in the identification of 12r and 19 as orally active inhibitors of p38 with significant efficacy in both acute and chronic models of inflammation.
Subject(s)
Anti-Inflammatory Agents/chemistry , Protein Kinase Inhibitors/chemistry , Pyridones/chemistry , p38 Mitogen-Activated Protein Kinases/antagonists & inhibitors , Administration, Oral , Animals , Anti-Inflammatory Agents/chemical synthesis , Anti-Inflammatory Agents/pharmacokinetics , Binding Sites , Catalytic Domain , Crystallography, X-Ray , Drug Discovery , Humans , JNK Mitogen-Activated Protein Kinases/antagonists & inhibitors , JNK Mitogen-Activated Protein Kinases/metabolism , Male , Microsomes, Liver/metabolism , Protein Kinase Inhibitors/chemical synthesis , Protein Kinase Inhibitors/pharmacokinetics , Pyridones/chemical synthesis , Pyridones/pharmacokinetics , Rats , Rats, Sprague-Dawley , Structure-Activity Relationship , p38 Mitogen-Activated Protein Kinases/metabolismABSTRACT
Discodermolide is a potentially important antitumor agent that stabilizes microtubules and blocks cells at the G2/M phase of the cell cycle in a manner similar to that of Taxol. Discodermolide also has unique properties that distinguish it from Taxol. In the present study, photoaffinity-labeled discodermolide analogues are used to investigate their binding site in tubulin. Three photoaffinity-labeled discodermolide analogues were synthesized, all of which promoted microtubule polymerization in the absence of GTP. The analogue, C19-[4-(4-(3)H-benzoyl-phenyl)-carbamate]-discodermolide (C19-[3H]BPC-discodermolide), was selected for photolabeling studies because it had the highest extent of photoincorporation, approximately 1%, of the three radiolabeled discodermolide analogues explored. Although compared to discodermolide, C19-BPC-discodermolide revealed no hypernucleation effect in the in vitro microtubule polymerization assay, it was more cytotoxic than discodermolide, and, like discodermolide, demonstrated synergism with Taxol. These results suggest that the hypernucleation effect of discodermolide is not involved in its cytotoxic activity. Similar to discodermolide, C19-BPC-discodermolide can effectively displace [3H]Taxol from microtubules, but Taxol cannot effectively displace C19-[3H]BPC-discodermolide binding. Discodermolide can effectively displace C19-[3H]BPC-discodermolide binding. Formic acid hydrolysis, immunoprecipitation experiments, and subtilisin digestion indicate that C19-BPC-discodermolide labels amino acid residues 305-433 in beta-tubulin. Further digestion with Asp-N and Arg-C enzymes suggested that C19-BPC-discodermolide binds to amino acid residues, 355-359, in beta-tubulin, which is in close proximity to the Taxol binding site. Molecular modeling guided by the above evidence led to a putative binding model for C19-BPC-discodermolide in tubulin.
Subject(s)
Alkanes/chemistry , Antineoplastic Agents/chemistry , Carbamates/chemistry , Lactones/chemistry , Models, Molecular , Peptides/chemistry , Photoaffinity Labels/chemistry , Pyrones/chemistry , Tubulin/chemistry , Alkanes/pharmacology , Antineoplastic Agents/pharmacology , Carbamates/pharmacology , Cell Division/drug effects , G2 Phase/drug effects , Humans , Lactones/pharmacology , Microtubules/chemistry , Microtubules/metabolism , Paclitaxel/chemistry , Paclitaxel/pharmacology , Peptides/metabolism , Photoaffinity Labels/pharmacology , Protein Binding , Protein Structure, Tertiary , Pyrones/pharmacology , Tubulin/metabolismABSTRACT
[structure: see text] The design, synthesis, and biological evaluation of a series of (+)-discodermolide molecular probes possessing photoaffinity and fluorescent appendages has been achieved. Stereoselective olefin cross-metathesis comprised a key tactic for construction of two of the molecular probes. Three photoaffinity probes were radiolabeled with tritium.
Subject(s)
Alkanes , Carbamates , Fluorescent Dyes , Lactones , Molecular Probes , Photoaffinity Labels , Pyrones , Alkanes/chemical synthesis , Alkanes/chemistry , Benzophenones/chemistry , Carbamates/chemical synthesis , Carbamates/chemistry , Fluorescent Dyes/chemical synthesis , Fluorescent Dyes/chemistry , Lactones/chemical synthesis , Lactones/chemistry , Molecular Probes/chemical synthesis , Molecular Probes/chemistry , Molecular Structure , Photoaffinity Labels/chemical synthesis , Photoaffinity Labels/chemistry , Pyrones/chemical synthesis , Pyrones/chemistry , StereoisomerismABSTRACT
[Structure: see text] The design, syntheses, and biological evaluation of 22 totally synthetic analogues of the potent microtubule-stabilizing agent (+)-discodermolide (1) have been achieved. Structure-activity relationships of the C(19) carbamate were defined, exploiting two synthetically simplified scaffolds, as well as the parent (+)-discodermolide framework.