The monoclonal antibody sotrovimab is no longer authorised by the Food and Drug Administration  to treat COVID-19 in certain US regions with high frequency of the omicron BA.2 subvariant. In a statement released by the FDA , the agency said that it is limiting the use of sotrovimab (branded as Xevudy by GlaxoSmithKline) in some US regions, mostly along the east coast, following data showing that the authorised dose of the monoclonal antibody — 500 mg — is unlikely to be effective against the BA.2 subvariant.