ABSTRACT
Fulvestrant is an estrogen receptor (ER) antagonist administered to breast cancer patients by monthly intramuscular injection. Given its present limitations of dosing and route of administration, a more flexible orally available compound has been sought to pursue the potential benefits of this drug in patients with advanced metastatic disease. Here we report the identification and characterization of AZD9496, a nonsteroidal small-molecule inhibitor of ERα, which is a potent and selective antagonist and downregulator of ERα in vitro and in vivo in ER-positive models of breast cancer. Significant tumor growth inhibition was observed as low as 0.5 mg/kg dose in the estrogen-dependent MCF-7 xenograft model, where this effect was accompanied by a dose-dependent decrease in PR protein levels, demonstrating potent antagonist activity. Combining AZD9496 with PI3K pathway and CDK4/6 inhibitors led to further growth-inhibitory effects compared with monotherapy alone. Tumor regressions were also seen in a long-term estrogen-deprived breast model, where significant downregulation of ERα protein was observed. AZD9496 bound and downregulated clinically relevant ESR1 mutants in vitro and inhibited tumor growth in an ESR1-mutant patient-derived xenograft model that included a D538G mutation. Collectively, the pharmacologic evidence showed that AZD9496 is an oral, nonsteroidal, selective estrogen receptor antagonist and downregulator in ER(+) breast cells that could provide meaningful benefit to ER(+) breast cancer patients. AZD9496 is currently being evaluated in a phase I clinical trial. Cancer Res; 76(11); 3307-18. ©2016 AACR.
Subject(s)
Breast Neoplasms/drug therapy , Cinnamates/pharmacology , Estrogen Receptor Modulators/pharmacology , Estrogen Receptor alpha/antagonists & inhibitors , Estrogen Receptor alpha/genetics , Indoles/pharmacology , Mutation/genetics , Administration, Oral , Animals , Apoptosis/drug effects , Breast Neoplasms/metabolism , Breast Neoplasms/pathology , Cell Proliferation/drug effects , Cinnamates/administration & dosage , Drug Evaluation, Preclinical , Estrogen Receptor Modulators/administration & dosage , Estrogen Receptor alpha/chemistry , Female , Humans , Indoles/administration & dosage , Mice , Mice, Inbred NOD , Mice, SCID , Protein Conformation , Rats , Tumor Cells, Cultured , Uterus/metabolism , Uterus/pathology , Xenograft Model Antitumor AssaysABSTRACT
The discovery of an orally bioavailable selective estrogen receptor downregulator (SERD) with equivalent potency and preclinical pharmacology to the intramuscular SERD fulvestrant is described. A directed screen identified the 1-aryl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole motif as a novel, druglike ER ligand. Aided by crystal structures of novel ligands bound to an ER construct, medicinal chemistry iterations led to (E)-3-(3,5-difluoro-4-((1R,3R)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenyl)acrylic acid (30b, AZD9496), a clinical candidate with high oral bioavailability across preclinical species that is currently being evaluated in phase I clinical trials for the treatment of advanced estrogen receptor (ER) positive breast cancer.
Subject(s)
Antineoplastic Agents/metabolism , Cinnamates/chemistry , Cinnamates/metabolism , Estrogen Antagonists/chemical synthesis , Estrogen Antagonists/pharmacology , Estrogen Receptor Modulators/chemical synthesis , Estrogen Receptor Modulators/pharmacology , Indoles/chemistry , Indoles/metabolism , Antineoplastic Agents/chemistry , Breast Neoplasms/drug therapy , Cell Line, Tumor , Cell Proliferation/drug effects , Clinical Trials, Phase I as Topic , Down-Regulation/drug effects , Drug Design , Female , Humans , Injections, Intramuscular , X-Ray DiffractionABSTRACT
High throughput screening followed by a lead generation campaign uncovered a novel series of urea containing morpholinopyrimidine compounds which act as potent and selective dual inhibitors of mTORC1 and mTORC2. We describe the continued compound optimization campaign for this series, in particular focused on identifying compounds with improved cellular potency, improved aqueous solubility, and good stability in human hepatocyte incubations. Knowledge from empirical SAR investigations was combined with an understanding of the molecular interactions in the crystal lattice to improve both cellular potency and solubility, and the composite parameters of LLE and pIC50-pSolubility were used to assess compound quality and progress. Predictive models were employed to efficiently mine the attractive chemical space identified resulting in the discovery of 42 (AZD3147), an extremely potent and selective dual inhibitor of mTORC1 and mTORC2 with physicochemical and pharmacokinetic properties suitable for development as a potential clinical candidate.
Subject(s)
Drug Discovery , Hepatocytes/drug effects , Multiprotein Complexes/antagonists & inhibitors , Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/pharmacology , Pyrimidines/chemistry , Pyrimidines/pharmacology , TOR Serine-Threonine Kinases/antagonists & inhibitors , Thiourea/analogs & derivatives , Cells, Cultured , Hepatocytes/cytology , Humans , Mechanistic Target of Rapamycin Complex 1 , Mechanistic Target of Rapamycin Complex 2 , Models, Molecular , Molecular Structure , Structure-Activity Relationship , Thiourea/chemistry , Thiourea/pharmacologyABSTRACT
Continuing efforts to establish a more general "user-friendly" protocol for the palladium-catalysed arylation of amines (Buchwald-Hartwig reaction) are described herein. Significant advances have been made through the use of the versatile (SIPr)Pd(methallyl)Cl complex in conjunction with the reliable base lithium hexamethyldisilazide (LHMDS).
Subject(s)
Amines/chemistry , Benzene Derivatives/chemistry , Organometallic Compounds/chemistry , Palladium/chemistry , Catalysis , Molecular Structure , Morpholines/chemistry , Organometallic Compounds/chemical synthesisABSTRACT
Starting from initial lead 1 containing a basic 5-substituent, optimisation of the glycolamide-derived neutral 5-substituent led to potent inhibitors of erbB2 with good pharmacokinetics. Representative compounds 19 and 21 inhibited phosphorylation of erbB2 in a mouse BT474C xenograft model after oral administration.
Subject(s)
Protein Kinase Inhibitors/pharmacology , Quinazolines/pharmacology , Receptor, ErbB-2/antagonists & inhibitors , Administration, Oral , Animals , Cell Line , Magnetic Resonance Spectroscopy , Mice , Neoplasm Transplantation , Phosphorylation , Protein Kinase Inhibitors/administration & dosage , Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/pharmacokinetics , Quinazolines/administration & dosage , Quinazolines/chemistry , Quinazolines/pharmacokinetics , Structure-Activity RelationshipABSTRACT
Neutral 5-substituted 4-anilinoquinazolines addressed high in vivo clearance and phospholipidosis associated with previous basic compounds. A representative compound 8a inhibited tumor growth in a mouse xenograft model when co-administered with the cytochrome P450 inhibitor 1-aminobenzotriazole (ABT), and data are consistent with pharmacology primarily reflecting inhibition of erbB2 receptor tyrosine kinase.
Subject(s)
Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacology , Neoplasms/drug therapy , Quinazolines/chemistry , Quinazolines/pharmacology , Receptor, ErbB-2/antagonists & inhibitors , Administration, Oral , Aniline Compounds/chemistry , Animals , Antineoplastic Agents/pharmacokinetics , Antineoplastic Combined Chemotherapy Protocols , Cell Proliferation/drug effects , Dogs , Drug Synergism , Mice , Molecular Structure , Quinazolines/pharmacokinetics , Rats , Triazoles/pharmacology , Xenograft Model Antitumor AssaysABSTRACT
The structure-activity and structure-property relationships of anilinoquinazoline inhibitors of EGFR were investigated. Strategies to lower volume of distribution and shorten half-life through structure and pKa modulation are discussed.
