RESUMO
Verubecestat 3 (MK-8931), a diaryl amide-substituted 3-imino-1,2,4-thiadiazinane 1,1-dioxide derivative, is a high-affinity ß-site amyloid precursor protein cleaving enzyme 1 (BACE1) inhibitor currently undergoing Phase 3 clinical evaluation for the treatment of mild to moderate and prodromal Alzheimer's disease. Although not selective over the closely related aspartyl protease BACE2, verubecestat has high selectivity for BACE1 over other key aspartyl proteases, notably cathepsin D, and profoundly lowers CSF and brain Aß levels in rats and nonhuman primates and CSF Aß levels in humans. In this annotation, we describe the discovery of 3, including design, validation, and selected SAR around the novel iminothiadiazinane dioxide core as well as aspects of its preclinical and Phase 1 clinical characterization.
Assuntos
Doença de Alzheimer/tratamento farmacológico , Precursor de Proteína beta-Amiloide/antagonistas & inibidores , Óxidos S-Cíclicos/farmacologia , Descoberta de Drogas , Tiadiazinas/farmacologia , Doença de Alzheimer/metabolismo , Precursor de Proteína beta-Amiloide/metabolismo , Animais , Óxidos S-Cíclicos/síntese química , Óxidos S-Cíclicos/química , Cães , Relação Dose-Resposta a Droga , Humanos , Macaca fascicularis , Modelos Moleculares , Estrutura Molecular , Ratos , Ratos Sprague-Dawley , Relação Estrutura-Atividade , Tiadiazinas/síntese química , Tiadiazinas/químicaRESUMO
We describe successful efforts to optimize the in vivo profile and address off-target liabilities of a series of BACE1 inhibitors represented by 6 that embodies the recently validated fused pyrrolidine iminopyrimidinone scaffold. Employing structure-based design, truncation of the cyanophenyl group of 6 that binds in the S3 pocket of BACE1 followed by modification of the thienyl group in S1 was pursued. Optimization of the pyrimidine substituent that binds in the S2'-S2â³ pocket of BACE1 remediated time-dependent CYP3A4 inhibition of earlier analogues in this series and imparted high BACE1 affinity. These efforts resulted in the discovery of difluorophenyl analogue 9 (MBi-4), which robustly lowered CSF and cortex Aß40 in both rats and cynomolgus monkeys following a single oral dose. Compound 9 represents a unique molecular shape among BACE inhibitors reported to potently lower central Aß in nonrodent preclinical species.
Assuntos
Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Peptídeos beta-Amiloides/metabolismo , Precursor de Proteína beta-Amiloide/metabolismo , Desenho de Fármacos , Compostos Heterocíclicos/química , Iminas/química , Peptídeos beta-Amiloides/líquido cefalorraquidiano , Animais , Córtex Cerebral/metabolismo , Inibidores Enzimáticos/farmacologia , Macaca fascicularis , Estrutura Molecular , Ratos , Relação Estrutura-AtividadeRESUMO
From an initial lead 1, a structure-based design approach led to identification of a novel, high-affinity iminohydantoin BACE1 inhibitor that lowers CNS-derived Aß following oral administration to rats. Herein we report SAR development in the S3 and F' subsites of BACE1 for this series, the synthetic approaches employed in this effort, and in vivo data for the optimized compound.
Assuntos
Doença de Alzheimer/tratamento farmacológico , Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Peptídeos beta-Amiloides/antagonistas & inibidores , Anticonvulsivantes/síntese química , Ácido Aspártico Endopeptidases/antagonistas & inibidores , Inibidores Enzimáticos/síntese química , Hidantoínas/síntese química , Administração Oral , Doença de Alzheimer/sangue , Doença de Alzheimer/líquido cefalorraquidiano , Secretases da Proteína Precursora do Amiloide/metabolismo , Peptídeos beta-Amiloides/sangue , Peptídeos beta-Amiloides/líquido cefalorraquidiano , Animais , Anticonvulsivantes/farmacologia , Ácido Aspártico Endopeptidases/metabolismo , Sítios de Ligação , Simulação por Computador , Cristalografia por Raios X , Modelos Animais de Doenças , Desenho de Fármacos , Inibidores Enzimáticos/farmacologia , Humanos , Hidantoínas/farmacologia , Modelos Moleculares , Ligação Proteica , Ratos , Ratos Sprague-DawleyRESUMO
Inhibition of BACE1 to prevent brain Aß peptide formation is a potential disease-modifying approach to the treatment of Alzheimer's disease. Despite over a decade of drug discovery efforts, the identification of brain-penetrant BACE1 inhibitors that substantially lower CNS Aß levels following systemic administration remains challenging. In this report we describe structure-based optimization of a series of brain-penetrant BACE1 inhibitors derived from an iminopyrimidinone scaffold. Application of structure-based design in tandem with control of physicochemical properties culminated in the discovery of compound 16, which potently reduced cortex and CSF Aß40 levels when administered orally to rats.