Another study showed neutralizing monoclonal antibody therapies are not effective when given after the patient is already hospitalized.

Efficacy and safety of two neutralising monoclonal antibody therapies, sotrovimab and BRII-196 plus BRII-198, for adults hospitalised with COVID-19 (TICO): a randomised controlled trial – The Lancet Infectious Diseases

Invited Commentary: Time to knock monoclonal antibodies off the platform for patients hospitalised with COVID-19