RESUMO
With the aim of reconsidering ICH S7B and E14 guidelines, a new in vitro assay system has been subjected to worldwide validation to establish a better prediction platform for potential drug-induced QT prolongation and the consequent TdP in clinical practice. In Japan, CSAHi HEART team has been working on hiPS-CMs in the MEA (hiPS-CMs/MEA) under a standardized protocol and found no inter-facility or lot-to-lot variability for proarrhythmic risk assessment of 7 reference compounds. In this study, we evaluated the responses of hiPS-CMs/MEA to another 31 reference compounds associated with cardiac toxicities, and gene expression to further clarify the electrophysiological characteristics over the course of culture period. The hiPS-CMs/MEA assay accurately predicted reference compounds potential for arrhythmogenesis, and yielded results that showed better correlation with target concentrations of QTc prolongation or TdP in clinical setting than other current in vitro and in vivo assays. Gene expression analyses revealed consistent profiles in all samples within and among the testing facilities. This report would provide CiPA with informative guidance on the use of the hiPS-CMs/MEA assay, and promote the establishment of a new paradigm, beyond conventional in vitro and in vivo assays for cardiac safety assessment of new drugs.
Assuntos
Síndrome do QT Longo/induzido quimicamente , Miócitos Cardíacos/efeitos dos fármacos , Arritmias Cardíacas/induzido quimicamente , Cardiotônicos/toxicidade , Eletrodos , Expressão Gênica , Guias como Assunto , Humanos , Técnicas In Vitro , Células-Tronco Pluripotentes Induzidas/efeitos dos fármacos , Células-Tronco Pluripotentes Induzidas/fisiologia , Ativação do Canal Iônico/genética , Japão , Contração Miocárdica/genética , Miócitos Cardíacos/fisiologiaRESUMO
In vitro screening of hERG channels are recommended under ICH S7B guidelines to predict drug-induced QT prolongation and Torsade de Pointes (TdP), whereas proarrhythmia is known to be evoked by blockage of other ion channels involved in cardiac contraction and compensation mechanisms. A consortium for drug safety assessment using human iPS cells-derived cardiomyocytes (hiPS-CMs), CSAHi, has been organized to establish a novel in vitro test system that would enable better prediction of drug-induced proarrhythmia and QT prolongation. Here we report the inter-facility and cells lot-to-lot variability evaluated with FPDc (corrected field potential duration), FPDc10 (10% FPDc change concentration), beat rate and incidence of arrhythmia-like waveform or arrest on hiPS-CMs in a multi-electrode array system. Arrhythmia-like waveforms were evident for all test compounds, other than chromanol 293B, that evoked FPDc prolongation in this system and are reported to induce TdP in clinical practice. There was no apparent cells lot-to-lot variability, while inter-facility variabilities were limited within ranges from 3.9- to 20-folds for FPDc10 and about 10-folds for the minimum concentration inducing arrhythmia-like waveform or arrests. In conclusion, the new assay model reported here would enable accurate prediction of a drug potential for proarrhythmia.
Assuntos
Arritmias Cardíacas/induzido quimicamente , Diferenciação Celular , Canal de Potássio ERG1/antagonistas & inibidores , Frequência Cardíaca/efeitos dos fármacos , Células-Tronco Pluripotentes Induzidas/efeitos dos fármacos , Microeletrodos , Miócitos Cardíacos/efeitos dos fármacos , Bloqueadores dos Canais de Potássio/toxicidade , Testes de Toxicidade/instrumentação , Potenciais de Ação , Arritmias Cardíacas/metabolismo , Arritmias Cardíacas/fisiopatologia , Bioensaio , Cardiotoxicidade , Técnicas de Cultura de Células , Células Cultivadas , Relação Dose-Resposta a Droga , Canal de Potássio ERG1/metabolismo , Desenho de Equipamento , Humanos , Células-Tronco Pluripotentes Induzidas/metabolismo , Japão , Miócitos Cardíacos/metabolismo , Observação , Reprodutibilidade dos Testes , Medição de Risco , Testes de Toxicidade/métodos , Testes de Toxicidade/normasRESUMO
Accumulation of Aß peptides is a hallmark of Alzheimer's disease (AD) and is considered a causal factor in the pathogenesis of AD. ß-Secretase (BACE1) is a key enzyme responsible for producing Aß peptides, and thus agents that inhibit BACE1 should be beneficial for disease-modifying treatment of AD. Here we describe the discovery and optimization of novel oxazine-based BACE1 inhibitors by lowering amidine basicity with the incorporation of a double bond to improve brain penetration. Starting from a 1,3-dihydrooxazine lead 6 identified by a hit-to-lead SAR following HTS, we adopted a p Ka lowering strategy to reduce the P-gp efflux and the high hERG potential leading to the discovery of 15 that produced significant Aß reduction with long duration in pharmacodynamic models and exhibited wide safety margins in cardiovascular safety models. This compound improved the brain-to-plasma ratio relative to 6 by reducing P-gp recognition, which was demonstrated by a P-gp knockout mouse model.
Assuntos
Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Peptídeos beta-Amiloides/metabolismo , Ácido Aspártico Endopeptidases/antagonistas & inibidores , Oxazinas/química , Fragmentos de Peptídeos/metabolismo , Inibidores de Proteases/química , Inibidores de Proteases/farmacologia , Subfamília B de Transportador de Cassetes de Ligação de ATP/genética , Subfamília B de Transportador de Cassetes de Ligação de ATP/metabolismo , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Secretases da Proteína Precursora do Amiloide/química , Animais , Ácido Aspártico Endopeptidases/química , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Cristalografia por Raios X , Cães , Desenho de Fármacos , Canal de Potássio ERG1/metabolismo , Cobaias , Humanos , Células Madin Darby de Rim Canino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Oxazinas/farmacologia , Inibidores de Proteases/farmacocinética , Relação Estrutura-AtividadeRESUMO
Several clinical reports showed that adverse effect profiles are not the same in morphine, oxycodone, and fentanyl. The authors investigated whether the relationship between plasma concentrations for antinociceptive effect and for various pharmacological effects differed among oxycodone, morphine, and fentanyl under controlled experimental setting using animal models. Oxycodone induced constipation and an antinociceptive effect in a similar concentration-dependent manner, whereas morphine required approximately 9-fold higher plasma concentration for antinociceptive effect compared with that for constipation when 50% effective plasma concentration (EC(50)) levels were compared. The EC(50) values for inhibition of behavioral activity were 2.1-, 2.7-, and 1.3-fold higher than those for antinociceptive effect in oxycodone, morphine, and fentanyl, respectively. Respiratory inhibition was observed even at higher plasma concentrations in all three opioids, and the differences in the EC(50) values compared with those for antinociceptive effects were 234.5-fold (oxycodone), 233.1-fold (morphine), or 104.2-fold (fentanyl). These results showed that oxycodone, morphine, and fentanyl exhibited unique patterns of plasma concentrations required for different pharmacological effects. The different adverse effect profiles observed in a clinical setting appear to be resulted from, at least in part, distinct intrinsic pharmacological profiles among these µ-opioid receptor agonists.