The combined treatment of Molnupiravir and Favipiravir results in a potentiation of antiviral efficacy in a SARS-CoV-2 hamster infection model

• DOI: 10.1016/j.ebiom.2021.103595
• Publication Date: 2021-09-24T12:44:11Z
• Authors: Rana Abdelnabi; Caroline S. Foo; Suzanne J.F. Kaptein; Xin Zhang; Thuc Nguyen Dan Do; Lana Langendries; Laura Vangeel; Judith Breuer; Juanita Pang; Rachel Williams; Valentijn Vergote; Elisabeth Heylen; Pieter Leyssen; Kai Dallmeier; Lotte Coelmont; Arnab K. Chatterjee; Raf Mols; Patrick Augustijns; Steven De Jonghe; Dirk Jochmans; Birgit Weynand; Johan Neyts
• Keywords: Favipiravir; Combination therapy; Antiviral drug; Mesocricetus; Infectious dose

Favipiravir and Molnupiravir, orally available antivirals, have been reported to exert antiviral activity against SARS-CoV-2. First efficacy data recently in COVID-19 patients.We here report on the combined effect of both drugs a SARS-CoV-2 Syrian hamster infection model. The infected hamsters were treated twice daily with vehicle (the control group) or suboptimal dose each compound combination compounds.When animals doses Molnupiravir at time infection, marked potency endpoint is observed. Infectious virus titers lungs are reduced by ∼5 log10 infectious no longer detected >60% animals. When start treatment was delayed one day reduction 2.4 achieved. Moreover, nearly completely prevented transmission co-housed untreated sentinels. Both result an increased mutation frequency remaining viral RNA recovered from In combo-treated hamsters, C-to-T mutations observed as compared single groups which may explain pronounced combination.Our findings lay basis for design clinical studies test Molnupiravir/Favipiravir COVID-19.stated acknowledgment.