Combinations of two drugs among NS3/4A inhibitors, NS5B inhibitors and non-selective antiviral agents are effective for hepatitis C virus with NS5A-P32 deletion in humanized-liver mice
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The emergence of a deletion mutant at hepatitis C virus (HCV) NS5A-P32 (P32del) has recently been reported in a subset of chronic hepatitis C patients who experience virologic failure after direct-acting antiviral drug (DAA) treatment. This mutation confers extremely high resistance to NS5A inhibitors. No effective treatment has been established for cases with this mutation.
We used a JFH1-based recombinant virus with NS5A from a genotype 1b strain to introduce a P32del mutation. We inoculated human hepatocyte chimeric mice with sera from a patient with ledipasvir/sofosbuvir therapy failure carrying a genotype 1b HCV with NS5A L31M and P32del or from a DAA-naïve patient carrying wild-type virus.
JFH1-based chimeric viruses with P32del showed sufficient levels of replication for in vitro assay despite the suppression of viral growth and infectious virus production. Variants with P32del exhibited severe resistance to all tested NS5A inhibitors, including daclatasvir, ledipasvir, elbasvir and velpatasvir, but were as susceptible to NS3/4A inhibitors, NS5B inhibitors, interferon alfa-2b, and ribavirin as wild-type viruses in the in vitro assay. The P32del mutant virus caused persistent infection in all inoculated chimeric mice with high viral titer and frequency. The virus was resistant to the ledipasvir/GS-558093 (a nucleotide analog inhibitor of NS5B polymerase) regimen but susceptible to either simeprevir plus GS-558093 or peg-interferon alfa-2b, compared to the wild-type virus.
Therapies combining at least two drugs among NS3/4A inhibitors, NS5B inhibitors and non-selective antiviral agents may be effective for HCV-infected patients with NS5A-P32del.
KeywordsDirect-acting antiviral drug (DAA) Resistance-associated substitutions (RASs) Recombinant HCV Humanized liver mice Thymidine kinase transgene (TK-NOG) mice
Hepatitis C virus
Direct-acting antiviral drug
NS5A-P32 deletion mutant
Thymidine kinase transgene
Sustained viral response
We would like to thank Gilead Sciences Inc. (Foster City, CA, USA) for providing ledipasvir and GS-558093. This work was partly supported by a Grant-in-Aid for Research on Hepatitis from the Japanese Agency for Medical Research and Development (JP18fk0210021, JP18fk0210002, JP18fk0210025), Ministry of Education, Culture, Sports, Science and Technology-Japan (JP16H05285), and Japan Society for the Promotion of Science (JP17K19647).
Dr. Tetsuo Takehara has received grants from Chugai Pharmaceutical Co. Ltd., Bristol-Myers Squibb, MSD K.K., AbbVie Inc. and Gilead Sciences. Dr. Tetsuo Takehara is on the speakers’ bureau for Bristol-Myers Squibb, MSD K.K., AbbVie Inc. and Gilead Sciences. Dr. Hayato Hikita has received grants from Bristol–Myers Squibb and MSD K.K. Dr. Ryotaro Sakamori and Dr. Tomohide Tatsumi have received grants from MSD K.K. Dr. Takahiro Kodama has received grants from MSD K.K. and Gilead Sciences. Dr. Yasuhiro Asahina belongs to a donation-funded department funded by Toray Industries Inc., Gilead Sciences, AbbVie GK, Chugai Pharmaceutical Co. Ltd., Fuji Rebio Inc., and Merck Sharp & Dohme.
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