The U.S. Food and Drug Administration issued an emergency use authorization (EUA) for the investigational monoclonal antibody therapy sotrovimab for the treatment of mild-to-moderate COVID-19 in adults and pediatric patients (12 years of age and older weighing at least 40 kilograms [about 88 pounds]) with positive results of direct SARS-CoV-2 viral testing and who are at high risk for progression to severe COVID-19, including hospitalisation or death.

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This includes, for example, individuals who are 65 years of age and older or individuals who have certain medical conditions. The safety and effectiveness of this investigational therapy continue to be evaluated for the treatment of COVID-19. Sotrovimab is not authorised for patients who are hospitalised due to COVID-19 or require oxygen therapy due to COVID-19. This treatment has not shown benefit in patients hospitalised due to COVID-19 and monoclonal antibodies may be associated with worse clinical outcomes when administered to hospitalised patients requiring high flow oxygen or mechanical ventilation.

"With the authorisation of this monoclonal antibody treatment, we are providing another option to help keep high-risk patients with COVID-19 out of the hospital," said Patrizia Cavazzoni, MD, director of the FDA’s Center for Drug Evaluation and Research. "It is important to expand the arsenal of monoclonal antibody therapies that are expected to retain activity against the circulating variants of COVID-19 in the United States".

Monoclonal antibodies are laboratory-made proteins that mimic the immune system’s ability to fight off harmful antigens such as viruses. Sotrovimab is a monoclonal antibody that is specifically directed against the spike protein of SARS-CoV-2 and is designed to block the virus’ attachment and entry into human cells.

The issuance of an EUA is different from FDA approval. In determining whether to issue an EUA, the FDA evaluates the totality of available evidence and carefully balances any known or potential risks with any known or potential benefits of the product for use during an emergency. Based on the FDA’s review of the totality of the scientific evidence available, the agency determined that it is reasonable to believe that sotrovimab may be effective in treating adults and certain pediatric patients with mild-to-moderate COVID-19. And, when used to treat COVID-19 for the authorised population, the known and potential benefits outweigh the known and potential risks for the drug. There are no adequate, approved and available alternative treatments to sotrovimab.

The data supporting this EUA for sotrovimab are based on an interim analysis from a phase 1/2/3 randomised, double-blind, placebo-controlled clinical trial in 583 non-hospitalised adults with mild-to-moderate COVID-19 symptoms and a positive SARS-CoV-2 test result. Of these patients, 291 received sotrovimab and 292 received a placebo within five days of onset of COVID-19 symptoms. The primary endpoint was progression of COVID-19 (defined as hospitalisation for greater than 24 hours for acute management of any illness or death from any cause) through day 29. Hospitalisation or death occurred in 21 (7%) patients who received placebo compared to 3 (1%) patients treated with sotrovimab, an 85% reduction.

The FDA is carefully monitoring circulating viral variants and their sensitivity to monoclonal antibodies authorised to treat COVID-19, including sotrovimab. Laboratory testing showed that sotrovimab retains activity against the current circulating variants first reported in the United Kingdom, South Africa, Brazil, California, New York and India.

The EUA allows for sotrovimab to be distributed and administered as a 500-milligram single dose intravenously by health care providers. The EUA requires that fact sheets that provide important information about using sotrovimab in treating COVID-19 be made available to health care providers and to patients, parents and caregivers, including dosing instructions, potential side effects and drug interactions. Potential side effects of sotrovimab include anaphylaxis and infusion-related reactions, rash and diarrhoea. The EUA was issued to GlaxoSmithKline.