National Infection Service, Public Health England, London NW9 5EQ, United Kingdom.
Section of Molecular Virology, Imperial College London, London W2 1PG, United Kingdom.
Proc Natl Acad Sci U S A. 2018 Nov 6;115(45):11613-11618. doi: 10.1073/pnas.1811345115. Epub 2018 Oct 23.
Favipiravir is a broad-spectrum antiviral that has shown promise in treatment of influenza virus infections. While emergence of resistance has been observed for many antiinfluenza drugs, to date, clinical trials and laboratory studies of favipiravir have not yielded resistant viruses. Here we show evolution of resistance to favipiravir in the pandemic H1N1 influenza A virus in a laboratory setting. We found that two mutations were required for robust resistance to favipiravir. We demonstrate that a K229R mutation in motif F of the PB1 subunit of the influenza virus RNA-dependent RNA polymerase (RdRP) confers resistance to favipiravir in vitro and in cell culture. This mutation has a cost to viral fitness, but fitness can be restored by a P653L mutation in the PA subunit of the polymerase. K229R also conferred favipiravir resistance to RNA polymerases of other influenza A virus strains, and its location within a highly conserved structural feature of the RdRP suggests that other RNA viruses might also acquire resistance through mutations in motif F. The mutations identified here could be used to screen influenza virus-infected patients treated with favipiravir for the emergence of resistance.
非那韦是一种广谱抗病毒药物，在治疗流感病毒感染方面显示出了潜力。虽然许多抗流感药物已经出现了耐药性，但迄今为止，对非那韦的临床试验和实验室研究尚未产生耐药病毒。在这里，我们在实验室环境中展示了大流行性 H1N1 流感 A 病毒对非那韦的耐药性演变。我们发现，对非那韦产生强大耐药性需要两种突变。我们证明流感病毒 RNA 依赖性 RNA 聚合酶（RdRP）的 PB1 亚基中的 motif F 中的 K229R 突变赋予了非那韦在体外和细胞培养中的耐药性。该突变对病毒适应性有代价，但通过聚合酶 PA 亚基中的 P653L 突变可以恢复适应性。K229R 还使其他流感 A 病毒株的 RNA 聚合酶对非那韦产生了耐药性，并且其在 RdRP 的高度保守结构特征内的位置表明，其他 RNA 病毒也可能通过 motif F 中的突变获得耐药性。这里鉴定的突变可用于筛选接受非那韦治疗的流感病毒感染患者，以发现耐药性的出现。
