T-705 (favipiravir) induces lethal mutagenesis in influenza A H1N1 viruses in vitro.

Abstract

Several novel anti-influenza compounds are in various phases of clinical development. One of these, T-705 (favipiravir), has a mechanism of action that is not fully understood but is suggested to target influenza virus RNA-dependent RNA polymerase. We investigated the mechanism of T-705 activity against influenza A (H1N1) viruses by applying selective drug pressure over multiple sequential passages in MDCK cells. We found that T-705 treatment did not select specific mutations in potential target proteins, including PB1, PB2, PA, and NP. Phenotypic assays based on cell viability confirmed that no T-705-resistant variants were selected. In the presence of T-705, titers of infectious virus decreased significantly (P < 0.0001) during serial passage in MDCK cells inoculated with seasonal influenza A (H1N1) viruses at a low multiplicity of infection (MOI; 0.0001 PFU/cell) or with 2009 pandemic H1N1 viruses at a high MOI (10 PFU/cell). There was no corresponding decrease in the number of viral RNA copies; therefore, specific virus infectivity (the ratio of infectious virus yield to viral RNA copy number) was reduced. Sequence analysis showed enrichment of G→A and C→T transversion mutations, increased mutation frequency, and a shift of the nucleotide profiles of individual NP gene clones under drug selection pressure. Our results demonstrate that T-705 induces a high rate of mutation that generates a nonviable viral phenotype and that lethal mutagenesis is a key antiviral mechanism of T-705. Our findings also explain the broad spectrum of activity of T-705 against viruses of multiple families.

• Authors: Tatiana Baranovich, Sook-San Wong, Jianling Armstrong, Henju Marjuki, Richard J Webby, Robert G Webster, Elena A Govorkova
• Journal: Journal of virology (J Virol) Vol. 87 Issue 7 Pg. 3741-51 (Apr 2013) ISSN: 1098-5514 [Electronic] United States
• PMID: 23325689 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• Amides
• Antiviral Agents
• Pyrazines
• favipiravir

Topics

• Amides (pharmacology)
• Analysis of Variance
• Animals
• Antiviral Agents (pharmacology)
• Dogs
• Drug Discovery (methods)
• In Vitro Techniques
• Influenza A Virus, H1N1 Subtype (drug effects, genetics, pathogenicity)
• Madin Darby Canine Kidney Cells
• Mutagenesis (drug effects, genetics)
• Orthomyxoviridae Infections (drug therapy)
• Pyrazines (pharmacology)
• Real-Time Polymerase Chain Reaction
• Reverse Transcriptase Polymerase Chain Reaction