(Reuters) — The U.S. Food and Drug Administration on Saturday issued emergency use authorization for Regeneron Pharmaceuticals Inc’s COVID-19 antibody therapy, an experimental treatment given to President Donald Trump that he said helped cure him of the disease.

The FDA said the monoclonal antibodies, casirivimab and imdevimab, should be administered together for the treatment of mild to moderate COVID-19 in adults and pediatric patients with positive results of direct SARS-CoV-2 viral testing and who are at high risk for progressing to severe COVID-19.

The treatment is part of a class of drugs known as monoclonal antibodies, which are manufactured copies of antibodies created by the human body to fight infections.

Regeneron’s REGEN-COV2 “antibody cocktail” – containing an antibody made by the company and a second isolated from humans who recovered from COVID-19 – is designed so that the two antibodies seek out and bind to the coronavirus’ spike protein to prevent it from entering healthy human cells.

Regeneron said on Saturday the clinical evidence from outpatient trial suggests that monoclonal antibodies such as REGEN-COV2 have the greatest benefit when given early after diagnosis and in patients who have not yet mounted their own immune response or who have high viral load.

The company said it expects to have does of REGEN-COV2 treatment ready for about 80,000 patients by the end of this month, about 200,000 patients by the first week of January and approximately 300,000 patients in total by the end of January.

The FDA said the antibodies are not authorized for patients who are hospitalized due to COVID-19 or require oxygen therapy due to COVID-19.