Selection of the highly replicative and partially multidrug resistant rtS78T HBV polymerase mutation during TDF-ETV combination therapy.

TitleSelection of the highly replicative and partially multidrug resistant rtS78T HBV polymerase mutation during TDF-ETV combination therapy.
Publication TypeJournal Article
Year of Publication2017
AuthorsShirvani-Dastgerdi, E, Winer, BY, Celià-Terrassa, T, Kang, Y, Tabernero, D, Yagmur, E, Rodríguez-Frías, F, Gregori, J, Luedde, T, Trautwein, C, Ploss, A, Tacke, F
JournalJ Hepatol
Date Published2017 Aug
KeywordsAdult, Antiviral Agents, Drug Resistance, Multiple, Viral, Drug Therapy, Combination, Female, Gene Products, pol, Genes, Viral, Guanine, Hepatitis B virus, Hepatitis B, Chronic, High-Throughput Nucleotide Sequencing, Humans, Male, Middle Aged, Mutation, RNA-Directed DNA Polymerase, Selection, Genetic, Sequence Analysis, DNA, Tenofovir, Virus Replication

<p><b>BACKGROUND & AIMS: </b>Patients chronically infected with the hepatitis B virus (HBV) and receiving long-term treatment with nucleoside or nucleotide analogues are at risk of selecting HBV strains with complex mutational patterns. We herein report two cases of HBV-infected patients with insufficient viral suppression, despite dual antiviral therapy with entecavir (ETV) and tenofovir (TDF). One patient died from aggressive hepatocellular carcinoma (HCC).</p><p><b>METHODS: </b>Serum samples from the two patients at different time points were analyzed using ultra-deep pyrosequencing analysis. HBV mutations were identified and transiently transfected into hepatoma cells in vitro using replication-competent HBV vectors, and functionally analyzed. We assessed replication efficacy, resistance to antivirals and potential impact on HBV secretion (viral particles, exosomes).</p><p><b>RESULTS: </b>Sequencing analyses revealed the selection of the rtS78T HBV polymerase mutation in both cases that simultaneously creates a premature stop codon at sC69 and thereby deletes almost the entire small HBV surface protein. One of the patients had an additional 261bp deletion in the preS1/S2 region. Functional analyses of the mutations in vitro revealed that the rtS78T/sC69∗ mutation, but not the preS1/S2 deletion, significantly enhanced viral replication and conferred reduced susceptibility to ETV and TDF. The sC69∗ mutation caused truncation of HBs protein, leading to impaired detection by commercial HBsAg assay, without causing intracellular HBsAg retention or affecting HBV secretion.</p><p><b>CONCLUSIONS: </b>The rtS78T/sC69∗ HBV mutation, associated with enhanced replication and insufficient response to antiviral treatment, may favor long-term persistence of these isolates. In addition to the increased production of HBV transcripts and the sustained secretion of viral particles in the absence of antigenic domains of S protein, this HBV mutation may predispose patients to carcinogenic effects.</p><p><b>LAY SUMMARY: </b>Long-term treatment with antiviral drugs carries the risk of selecting mutations in the hepatitis B virus (HBV). We herein report two cases of patients with insufficient response to dual tenofovir and entecavir therapy. Molecular analyses identified a distinct mutation, rtS78T/sC69∗, that abolishes HBsAg detection, enhances replication, sustains exosome-mediated virion secretion and decreases susceptibility to antivirals, thereby representing a potentially high-risk mutation for HBV-infected individuals.</p>

Alternate JournalJ Hepatol
PubMed ID28392234
PubMed Central IDPMC6016549
Grant ListF31 AI122480 / AI / NIAID NIH HHS / United States
T32 GM007388 / GM / NIGMS NIH HHS / United States