ABSTRACT
A discovery program targeting respiratory syncytial virus (RSV) identified C-nucleoside 4 (RSV A2 EC50 = 530 nM) as a phenotypic screening lead targeting the RSV RNA-dependent RNA polymerase (RdRp). Prodrug exploration resulted in the discovery of remdesivir (1, GS-5734) that is >30-fold more potent than 4 against RSV in HEp-2 and NHBE cells. Metabolism studies in vitro confirmed the rapid formation of the active triphosphate metabolite, 1-NTP, and in vivo studies in cynomolgus and African Green monkeys demonstrated a >10-fold higher lung tissue concentration of 1-NTP following molar normalized IV dosing of 1 compared to that of 4. A once daily 10 mg/kg IV administration of 1 in an African Green monkey RSV model demonstrated a >2-log10 reduction in the peak lung viral load. These early data following the discovery of 1 supported its potential as a novel treatment for RSV prior to its development for Ebola and approval for COVID-19 treatment.
Subject(s)
Adenosine Monophosphate/analogs & derivatives , Alanine/analogs & derivatives , Antiviral Agents/pharmacology , Prodrugs/pharmacology , Respiratory Syncytial Virus Infections/drug therapy , Respiratory Syncytial Virus, Human/drug effects , Adenosine Monophosphate/pharmacology , Alanine/pharmacology , Animals , Antiviral Agents/chemistry , Antiviral Agents/pharmacokinetics , Caco-2 Cells , Cells, Cultured , Chlorocebus aethiops , Disease Models, Animal , Dogs , Drug Evaluation, Preclinical/methods , Epithelial Cells/virology , Humans , Macaca fascicularis , Male , Prodrugs/chemistry , Prodrugs/pharmacokinetics , Rats, Sprague-Dawley , Respiratory Syncytial Virus Infections/virology , Structure-Activity Relationship , Tissue Distribution , Tubercidin/analogs & derivatives , Tubercidin/chemistry , Viral LoadABSTRACT
Structure-based rational design and extensive structure-activity relationship studies led to the discovery of AMG 232 (1), a potent piperidinone inhibitor of the MDM2-p53 association, which is currently being evaluated in human clinical trials for the treatment of cancer. Further modifications of 1, including replacing the carboxylic acid with a 4-amidobenzoic acid, afforded AM-7209 (25), featuring improved potency (KD from ITC competition was 38 pM, SJSA-1 EdU IC50 = 1.6 nM), remarkable pharmacokinetic properties, and in vivo antitumor activity in both the SJSA-1 osteosarcoma xenograft model (ED50 = 2.6 mg/kg QD) and the HCT-116 colorectal carcinoma xenograft model (ED50 = 10 mg/kg QD). In addition, 25 possesses distinct mechanisms of elimination compared to 1.
Subject(s)
Antineoplastic Agents/pharmacology , Cell Proliferation/drug effects , Colonic Neoplasms/drug therapy , Drug Discovery , Protein Binding/drug effects , Proto-Oncogene Proteins c-mdm2/antagonists & inhibitors , Tumor Suppressor Protein p53/antagonists & inhibitors , Animals , Antineoplastic Agents/chemistry , Colonic Neoplasms/metabolism , Colonic Neoplasms/pathology , Female , Humans , Mice , Mice, Nude , Models, Molecular , Molecular Structure , Proto-Oncogene Proteins c-mdm2/metabolism , Structure-Activity Relationship , Tumor Cells, Cultured , Tumor Suppressor Protein p53/metabolismABSTRACT
We previously reported the discovery of potent and selective morpholinone and piperidinone inhibitors of the MDM2-p53 interaction. These inhibitors have in common a carboxylic acid moiety that engages in an electrostatic interaction with MDM2-His96. Our continued search for potent and diverse inhibitors led to the discovery of novel replacements for these acids uncovering new interactions with the MDM2 protein. In particular, using pyridine or thiazole as isosteres of the carboxylic acid moiety resulted in very potent analogues. From these, AM-6761 (4) emerged as a potent inhibitor with remarkable biochemical (HTRF IC50 = 0.1 nM) and cellular potency (SJSA-1 EdU IC50 = 16 nM), as well as favorable pharmacokinetic properties. Compound 4 also shows excellent antitumor activity in the SJSA-1 osteosarcoma xenograft model with an ED50 of 11 mg/kg. Optimization efforts toward the discovery of these inhibitors as well as the new interactions observed with the MDM2 protein are described herein.
Subject(s)
Acetates/pharmacology , Antineoplastic Agents/pharmacology , Carboxylic Acids/pharmacology , Cell Proliferation/drug effects , Myocytes, Smooth Muscle/drug effects , Piperidones/pharmacology , Protein Interaction Domains and Motifs/drug effects , Proto-Oncogene Proteins c-mdm2/antagonists & inhibitors , Tumor Suppressor Protein p53/antagonists & inhibitors , Acetates/chemistry , Animals , Bone Neoplasms/drug therapy , Carboxylic Acids/chemistry , Cells, Cultured , Crystallography, X-Ray , Drug Design , Female , Humans , Hydrogen Bonding , Mice , Mice, Nude , Models, Molecular , Molecular Structure , Osteosarcoma/drug therapy , Piperidones/chemistry , Protein Binding , Proto-Oncogene Proteins c-mdm2/metabolism , Stereoisomerism , Structure-Activity Relationship , Tumor Cells, Cultured , Tumor Suppressor Protein p53/metabolism , Xenograft Model Antitumor AssaysABSTRACT
We previously reported the discovery of AMG 232, a highly potent and selective piperidinone inhibitor of the MDM2-p53 interaction. Our continued search for potent and diverse analogues led to the discovery of novel morpholinone MDM2 inhibitors. This change to a morpholinone core has a significant impact on both potency and metabolic stability compared to the piperidinone series. Within this morpholinone series, AM-8735 emerged as an inhibitor with remarkable biochemical potency (HTRF IC50 = 0.4 nM) and cellular potency (SJSA-1 EdU IC50 = 25 nM), as well as pharmacokinetic properties. Compound 4 also shows excellent antitumor activity in the SJSA-1 osteosarcoma xenograft model with an ED50 of 41 mg/kg. Lead optimization toward the discovery of this inhibitor as well as key differences between the morpholinone and the piperidinone series will be described herein.
Subject(s)
Acetates/chemical synthesis , Acetates/pharmacology , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/pharmacology , Morpholines/chemical synthesis , Morpholines/pharmacology , Proto-Oncogene Proteins c-mdm2/antagonists & inhibitors , Proto-Oncogene Proteins c-mdm2/chemistry , Tumor Suppressor Protein p53/antagonists & inhibitors , Tumor Suppressor Protein p53/chemistry , Animals , Cell Line, Tumor , Crystallography, X-Ray , Drug Discovery , Humans , Indicators and Reagents , Mice , Models, Molecular , Molecular Conformation , Morpholines/pharmacokinetics , Rats , Structure-Activity Relationship , Xenograft Model Antitumor AssaysABSTRACT
We recently reported the discovery of AM-8553 (1), a potent and selective piperidinone inhibitor of the MDM2-p53 interaction. Continued research investigation of the N-alkyl substituent of this series, focused in particular on a previously underutilized interaction in a shallow cleft on the MDM2 surface, led to the discovery of a one-carbon tethered sulfone which gave rise to substantial improvements in biochemical and cellular potency. Further investigation produced AMG 232 (2), which is currently being evaluated in human clinical trials for the treatment of cancer. Compound 2 is an extremely potent MDM2 inhibitor (SPR KD = 0.045 nM, SJSA-1 EdU IC50 = 9.1 nM), with remarkable pharmacokinetic properties and in vivo antitumor activity in the SJSA-1 osteosarcoma xenograft model (ED50 = 9.1 mg/kg).