Center for Medical Specialist Graduate Education and Research, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.
Am J Gastroenterol. 2013 Sep;108(9):1464-72. doi: 10.1038/ajg.2013.205. Epub 2013 Jul 30.
Direct-acting antiviral agents (DAAs) against hepatitis C virus (HCV) have recently been developed and are ultimately hoped to replace interferon-based therapy. However, DAA monotherapy results in rapid emergence of resistant strains and DAAs must be used in combinations that present a high genetic barrier to resistance, although viral kinetics of multidrug-resistant strains remain poorly characterized. The aim of this study is to track the emergence and fitness of resistance using combinations of telaprevir and NS5A or NS5B inhibitors with genotype 1b clones.
HCV-infected chimeric mice were treated with DAAs, and resistance was monitored using direct and ultra-deep sequencing.
Combination therapy with telaprevir and BMS-788329 (NS5A inhibitor) reduced serum HCV RNA to undetectable levels. The presence of an NS3-V36A telaprevir resistance mutation resulted in poor response to telaprevir monotherapy but showed significant HCV reduction when telaprevir was combined with BMS-788329. However, a BMS-788329-resistant strain emerged at low frequency. Infection with a BMS-788329-resistant NS5A-L31V mutation rapidly resulted in gain of an additional NS5A-Y93A mutation that conferred telaprevir resistance during combination therapy. Infection with dual NS5AL31V/NS5AY93H mutations resulted in poor response to combination therapy and development of telaprevir resistance. Although HCV RNA became undetectable soon after the beginning of combination therapy with BMS-788329 and BMS-821095 (NS5B inhibitor), rebound with emergence of resistance against all three drugs occurred. Triple resistance also occurred following infection with the NS3V36A/NS5AL31V/NS5AY93H triple mutation.
Resistant strains easily develop from cloned virus strains. Sequential use of DAAs should be avoided to prevent emergence of multidrug-resistant strains.
直接作用抗病毒药物（DAA）针对丙型肝炎病毒（HCV）已被研发出来，有望最终取代基于干扰素的治疗方法。然而，DAA 单药治疗会迅速产生耐药株，且必须联合使用具有高耐药基因屏障的 DAA，尽管多药耐药株的病毒动力学仍描述不佳。本研究旨在通过基因 1b 克隆的 telaprevir 和 NS5A 或 NS5B 抑制剂组合跟踪耐药的出现和适应性。
用 DAA 治疗 HCV 感染嵌合小鼠，通过直接和超深度测序监测耐药性。
telaprevir 和 BMS-788329（NS5A 抑制剂）联合治疗将血清 HCV RNA 降低至不可检测水平。存在 NS3-V36A telaprevir 耐药突变会导致 telaprevir 单药治疗反应不佳，但当 telaprevir 与 BMS-788329 联合使用时，HCV 明显减少。然而，BMS-788329 耐药株以低频率出现。感染 BMS-788329 耐药 NS5A-L31V 突变迅速导致获得另外一个 NS5A-Y93A 突变，在联合治疗时赋予 telaprevir 耐药性。感染双重 NS5A-L31V/NS5A-Y93H 突变导致对联合治疗反应不佳和 telaprevir 耐药的发展。尽管在 BMS-788329 和 BMS-821095（NS5B 抑制剂）联合治疗开始后不久 HCV RNA 变得不可检测，但所有三种药物的耐药性反弹发生。感染 NS3-V36A/NS5A-L31V/NS5A-Y93H 三重突变也会导致三重耐药。
耐药株很容易从克隆病毒株中产生。为了防止多药耐药株的出现，应避免连续使用 DAA。
