ABSTRACTThe exceptionalin vitropotency of the hepatitis C virus (HCV) NS5A inhibitor BMS-790052 has translated into anin vivoeffect in proof-of-concept clinical trials. Although the 50% effective concentration (EC50) of the initial lead, the thiazolidinone BMS-824, was ∼10 nM in the replicon assay, it underwent transformation to other inhibitory species after incubation in cell culture medium. The biological profile of BMS-824, including the EC50, the drug concentration required to reduce cell growth by 50% (CC50), and the resistance profile, however, remained unchanged, triggering an investigation to identify the biologically active species. High-performance liquid chromatography (HPLC) biogram fractionation of a sample of BMS-824 incubated in medium revealed that the most active fractions could readily be separated from the parental compound and retained the biological profile of BMS-824. From mass spectral and nuclear magnetic resonance data, the active species was determined to be a dimer of BMS-824 derived from an intermolecular radical-mediated reaction of the parent compound. Based upon an analysis of the structural elements of the dimer deemed necessary for anti-HCV activity, the stilbene derivative BMS-346 was synthesized. This compound exhibited excellent anti-HCV activity and showed a resistance profile similar to that of BMS-824, with changes in compound sensitivity mapped to the N terminus of NS5A. The N terminus of NS5A has been crystallized as a dimer, complementing the symmetry of BMS-346 and allowing a potential mode of inhibition of NS5A to be discussed. Identification of the stable, active pharmacophore associated with these NS5A inhibitors provided the foundation for the design of more potent inhibitors with broad genotype inhibition. This culminated in the identification of BMS-790052, a compound that preserves the symmetry discovered with BMS-346.
摘要丙型肝炎病毒(HCV)NS5A抑制剂BMS-790052的超强生命力已在概念验证临床试验中转化为活体效应。虽然最初的先导药物噻唑烷酮 BMS-824 在复制子实验中的 50% 有效浓度(EC50)为 10 nM,但在细胞培养基中培养后,它已转变为其他抑制种类。然而,BMS-824 的生物学特性,包括半数致死浓度(EC50)、使细胞生长减少 50%所需的药物浓度(CC50)和耐药性特性保持不变,这引发了对生物活性物种的鉴定研究。对培养基中培养的 BMS-824 样品进行高效液相色谱(HPLC)生物图谱分馏后发现,最有活性的馏分很容易从母体化合物中分离出来,并保留了 BMS-824 的生物特征。根据质谱和核磁共振数据,活性物种被确定为 BMS-824 的二聚体,来自母体化合物分子间自由基介导的反应。根据对二聚体结构元素的分析,认为该二聚体具有抗 HCV 活性的必要条件,合成了二苯乙烯衍生物 BMS-346。该化合物表现出卓越的抗 HCV 活性,并显示出与 BMS-824 相似的耐药性特征,化合物敏感性的变化映射到 NS5A 的 N 末端。NS5A的N末端已结晶为二聚体,补充了BMS-346的对称性,从而可以讨论NS5A的潜在抑制模式。确定与这些 NS5A 抑制剂相关的稳定、活性药理机制为设计具有广泛基因型抑制作用的更强效抑制剂奠定了基础。最终,BMS-790052 被鉴定出来,这是一种保留了 BMS-346 对称性的化合物。