US officials have granted emergency authorisation for an experimental antibody treatment given to President Trump after his Covid-19 diagnosis.
The drug, developed by Regeneron, will be allowed for use in people who have tested positive for the virus and are at risk of severe illness.
Studies suggest the therapy is effective when administered early after diagnosis, the company says.
It comes as Covid-19 cases in the country continue to rise.
Emergency authorisation by the Food and Drug Administration (FDA) allows use of a treatment while studies are carried out to determine safety and effectiveness.
A similar drug made by Eli Lilly, another US pharmaceutical firm, was given emergency approval