Prophylactic efficacy of a human monoclonal antibody against MERS-CoV in the common marmoset

de Wit, Emmie; Feldmann, Friederike; Horne, Eva; Okumura, Atsushi; Cameroni, Elisabetta; Haddock, Elaine; Saturday, Greg; Scott, Dana; Gopal, Robin; Zambon, Maria; Corti, Davide; Feldmann, Heinz

Effective antiviral treatments for MERS-CoV are urgently needed. LCA60 is a MERS-CoV-neutralizing monoclonal antibody isolated from a convalescent MERS patient. Previously, it was shown that treatment with LCA60 resulted in reduced disease and virus titers in mouse models of MERS-CoV infection. Here, we tested the prophylactic efficacy of LCA60 in the common marmoset model of MERS-CoV infection. Intravenous administration of LCA60 one day before virus challenge resulted in high levels of MERS-CoV-neutralizing activity in circulating blood. Clinically, there was a moderate benefit of treatment with LCA60 including reduced respiratory involvement. Although viral lung loads were not reduced in LCA60-treated animals as compared to controls, there were fewer pathological changes in the lungs. Thus, prophylactic LCA60 treatment could be implemented to reduce disease burden in contacts of confirmed MERS-CoV patients.