PDF(Pubmed)
Abstract：
Paxlovid is the first approved oral treatment for coronavirus disease 2019 and includes nirmatrelvir, a protease inhibitor targeting the main protease (Mpro) of SARS-CoV-2, as one of the key components. While some specific mutations emerged in Mpro were revealed to significantly reduce viral susceptibility to nirmatrelvir in vitro, there is no report regarding resistance to nirmatrelvir in patients and animal models for SARS-CoV-2 infection yet. We recently developed xenograft tumors derived from Calu-3 cells in immunodeficient mice and demonstrated extended replication of SARS-CoV-2 in the tumors. In this study, we investigated the effect of nirmatrelvir administration on SARS-CoV-2 replication. Treatment with nirmatrelvir after virus infection significantly reduced the replication of the parental SARS-CoV-2 and SARS-CoV-2 Omicron at 5 days post-infection (dpi). However, the virus titers were completely recovered at the time points of 15 and 30 dpi. The virus genomes in the tumors at 30 dpi were analyzed to investigate whether nirmatrelvir-resistant mutant viruses had emerged during the extended replication of SARS-CoV-2. Various mutations in several genes including ORF1ab, ORF3a, ORF7a, ORF7b, ORF8, and N occurred in the SARS-CoV-2 genome; however, no mutations were induced in the Mpro sequence by a single round of nirmatrelvir treatment, and none were observed even after two rounds of treatment. The parental SARS-CoV-2 and its sublineage isolates showed similar IC50 values of nirmatrelvir in Vero E6 cells. Therefore, it is probable that inducing viral resistance to nirmatrelvir in vivo is challenging differently from in vitro passage.
摘要：
Paxlovid是2019年第一个批准的冠状病毒病口服治疗药物，包括尼马特雷韦，以SARS-CoV-2的主要蛋白酶（Mpro）为目标的蛋白酶抑制剂，是关键成分之一。虽然Mpro中出现的一些特定突变在体外显着降低了病毒对nirmatrelvir的易感性，目前尚无关于SARS-CoV-2感染的患者和动物模型对nirmatrelvir耐药的报道.我们最近在免疫缺陷小鼠中开发了源自Calu-3细胞的异种移植肿瘤，并证明了SARS-CoV-2在肿瘤中的扩展复制。在这项研究中,我们研究了nirmatrelvir给药对SARS-CoV-2复制的影响。在病毒感染后5天(dpi),用nirmatrelvir治疗显著减少了亲本SARS-CoV-2和SARS-CoV-2Omicron的复制。然而,病毒滴度在15和30dpi的时间点完全恢复。分析了30dpi时肿瘤中的病毒基因组，以研究在SARS-CoV-2的扩展复制过程中是否出现了耐尼马特雷韦的突变病毒。包括ORF1ab在内的几种基因中的各种突变，ORF3a,ORF7a,ORF7b,ORF8和N发生在SARS-CoV-2基因组中；然而，单轮尼马特雷韦治疗在Mpro序列中没有诱导突变，即使经过两轮治疗，也没有观察到。亲本SARS-CoV-2及其亚谱系分离株在VeroE6细胞中显示出相似的nirmatrelvirIC50值。因此,很可能在体内诱导病毒对尼马特雷韦的抗性与体外传代不同。
