Effects of Combinations of Favipiravir (T-705) and Oseltamivir on Influenza A (H1N1, H3N2, and H5N1) Virus Infections in MiceAntimicrob Agents Chemother (2009)
AbstractFavipiravir (T-705 [6-ﬂuoro-3-hydroxy-2-pyrazinecarboxamide]) and oseltamivir were combined to treat inﬂuenza virus A/NWS/33 (H1N1), A/Victoria/3/75 (H3N2), and A/Duck/MN/1525/81 (H5N1) infections. T-705 alone inhibited viruses in cell culture at 1.4 to 4.3 µM. Oseltamivir inhibited these three viruses in cells at 3.7, 0.02, and 0.16 µM and in neuraminidase assays at 0.94, 0.46, and 2.31 nM, respectively. Oral treatments were given twice daily to mice for 5 to 7 days starting, generally, 24 h after infection. Survival resulting from 5 days of oseltamivir treatment (0.1 and 0.3 mg/kg/day) was signiﬁcantly better in combination with 20 mg/kg of body weight/day of T-705 against the H1N1 infection. Treatment of the H3N2 infection required 50 mg/kg/day of oseltamivir for 7 days to achieve 60% protection; 25 mg/kg/day was ineffective. T-705 was >70% protective at 50 to 100 mg/kg/day but inactive at 25 mg/kg/day. The combination of inhibitors (25 mg/kg/day each) increased survival to 90%. The H5N1 infection was not beneﬁted by treatment with oseltamivir (<100 mg/kg/day for 7 days). T-705 was 30 to 70% protective at 25 to 100 mg/kg/day. Survival improved slightly with combination treatments. Increased activity was seen against H5N1 infection by starting treatments 2 h before infection. Oseltamivir was ineffective at <40 mg/kg/day. T-705 was 100% protective at 40 and 80 mg/kg/day and inactive at 20 mg/kg/day. Combining ineffective doses (20 mg/kg/day of T-705 and 10 to 40 mg/kg/day of oseltamivir) afforded 60 to 80% protection and improved body weights during infection. Thus, synergistic responses were achieved with low doses of T-705 combined with oseltamivir. These compounds may be viable candidates for combination treatment of human inﬂuenza infections.
- influenza A
Publication DateJanuary 1, 2009
Citation InformationSmee, D. F., B. L. Hurst, M. H. Wong, K. W. Bailey, E. B. Tarbet, J. D. Morrey, and Y. Furuta. 2009. Effects of Combinations of Favipiravir (T-705) and Oseltamivir on Influenza A (H1N1, H3N2, and H5N1) Virus Infections in Mice. Antimicrob Agents Chemother. PMID19901093 PMCPMC2798555