Rapid In Vitro Evolution of Human Cytomegalovirus UL56 Mutations That Confer Letermovir Resistance
Rapid In Vitro Evolution of Human Cytomegalovirus UL56 Mutations That Confer Letermovir Resistance
复制标题
DOI：
10.1128/aac.01623-15
复制
发表时间：
2015-10-01
影响因子：
4.9
通讯作者：
Chou, Sunwen
中科院分区：
文献类型：
--
作者：
Chou, Sunwen
Letermovir (LMV) 是一种实验性巨细胞病毒终止酶抑制剂，正在进行 3 期临床试验。 UL56 密码子 231 至 369 处的病毒突变已被描述，这些突变赋予 LMV 抗性水平差异很大。在这项研究中，在 LMV 浓度不断升高的情况下，进行了 15 项独立实验，复制了 7 个已发表的 UL56 突变中的 6 个，并通常在 UL56 密码子 231、236、237、244、257、261、325 和 329 处引发额外的抗性突变。突变最早在 LMV 中检测到。 （中位数，3 个通道）比 8 个平行 膦甲酸实验（中位数，15 次传代）。随着 LMV 浓度增加，典型的初始 UL56 变化为 F261L（赋予低级抗性），与赋予高级抗性的突变组合或替换，最终使病毒在 30 mu M LMV 中正常生长（> 野生型 50% 有效浓度 [EC50] 的 5,000 倍）。在高 LMV 浓度下，通常会检测到 UL56 变化 C325F/R，以及密码子 236、257、329 和/或 369 处的变化组合。构建含有单个 UL56 突变和组合的重组病毒，以确认其抗性表型和细胞培养物中的正常生长。一些双突变体和三突变体比各自的单突变体表现出更高的 LMV 抗性，特别是那些在密码子 236 和 257 处均发生变化的突变体。在对病毒生长影响最小的情况下实现高级 LMV 抗性的途径的多样性表明病毒遗传屏障较低，并且在治疗活动性感染期间需要密切监测。
Letermovir (LMV) is an experimental cytomegalovirus terminase inhibitor undergoing phase 3 clinical trials. Viral mutations have been described at UL56 codons 231 to 369 that confer widely variable levels of LMV resistance. In this study, 15 independent experiments propagating an exonuclease mutant viral strain in escalating LMV concentrations replicated 6 of the 7 published UL56 mutations and commonly elicited additional resistance-conferring mutations at UL56 codons 231, 236, 237, 244, 257, 261, 325, and 329. Mutations were first detected earlier in LMV (median, 3 passages) than in 8 parallel experiments with foscarnet (median, 15 passages). As LMV concentrations increased, the typical initial UL56 change F261L, which confers low-grade resistance, combined or was replaced with mutations conferring higher-grade resistance, eventually enabling normal viral growth in 30 mu M LMV (>5,000-fold the 50% effective concentration [EC50] for the wild type). At high LMV concentrations, the UL56 changes C325F/R were commonly detected, as well as a combination of changes at codons 236, 257, 329, and/or 369. Recombinant viruses containing individual UL56 mutations and combinations were constructed to confirm their resistance phenotypes and normal growth in cell culture. Several double and triple mutants showed much higher LMV resistance than the respective single mutants, particularly those including changes at both codons 236 and 257. The multiplicity of pathways to high-grade LMV resistance with minimal viral growth impact suggests a low viral genetic barrier and the need for close monitoring during treatment of active infection.