The U.S. Food and Drug Administration (FDA) has given the green light on the investigational monoclonal antibody therapy, sotrovimab, as a treatment for coronavirus disease 2019 (COVID-19).
The regulatory agency granted an Emergency Use Authorization (EUA) for sotrovimab, previously called VIR-7831, to treat mild to moderate COVID-19, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The therapy, which was developed by GlaxoSmithKline (GSK) and Vir Biotechnology, is a single-dose monoclonal antibody intended for adults and pediatric patients 12 years and above, weighing at least 40 kilograms.
What is a monoclonal antibody therapy?
Monoclonal antibodies are laboratory-made proteins that mimic the immune system’s ability to ward off harmful pathogens like viruses.
The immune system produces antibodies as a defense mechanism against foreign molecules that are registered in the body. Particular viral or bacterial proteins, known as antigens, trigger the development of antibodies. These bind to the antigenic targets on the pathogen and prevent the infection of host cells.
The main antigenic target of vaccines and therapies for COVID-19 has thus far been SARS-CoV-2’s spike protein. This is the viral protein that mediates viral entry into host cells and thus facilitates infection.
The treatment is a novel way of treating COVID-19 for people who have tested positive for the virus and are at high risk for developing severe illness. These include older adults, immunocompromised people, and those with underlying health conditions like diabetes, hypertension, heart problem, and respiratory illness, among others.
The therapy has been designed to prevent hospitalizations, reduce viral loads, and alleviate symptom severity.
Sotrovimab monoclonal antibody therapy
The FDA authorization was based on the interim efficacy and safety results from the phase III COVID-19 Monoclonal antibody Efficacy Trial – Intent to Care Early (COMET-ICE) trial in adult outpatients who are at high risk of developing severe COVID-19. An independent data monitoring committee has halted the clinical trial since the therapy is highly effective.
In the randomized, double-blind, placebo-controlled clinical trial in 583 non-hospitalized adults with mild to moderate COVID-19 symptoms, the use of sotrovimab resulted in an 85 percent reduction in the risk of hospitalization or death in high-risk individuals, compared with those in the control group.
Meanwhile, only rare and mild adverse effects were noted, including rash and diarrhea. In the trial, there have been no reports of adverse events, showing that the therapy is safe to use in COVID-19 patients. Moreover, the data showed that sotrovimab maintains its activity against all known variants of concern, including the U.K. and Indian variants of concern. This is because sotrovimab “targets a conserved epitope of the spike protein that is less likely to mutate over time.”
“With the authorization of this monoclonal antibody treatment, we are providing another option to help keep high-risk patients with COVID-19 out of the hospital,” Dr. Patrizia Cavazzoni, 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,” she added.
The FDA is carefully monitoring viral variants and their sensitivity to the approved monoclonal antibodies. Its approval allows for sotrovimab to be distributed and administered as a 500-milligram single dose intravenously by health care providers. The treatment will be available in the United States in the coming weeks.
The fast pace of COVID-19 vaccinations in the U.S. is encouraging, yet, despite these aggressive efforts, there is still a need to help prevent infected patients from developing complications. In just over a year since starting our collaboration and in less than 10 months since beginning clinical trials, we are delighted that, as of today, the benefits of this unique monoclonal antibody will now be available to patients in need,” Dr. Hal Barron, chief scientific officer, and president R&D, GSK, explained.
The monoclonal antibody therapy, sotrovimab, is being studied in ongoing trials. By the first half of 2021, a report of the safety and efficacy analysis at day 29 for the full population from the COMET-ICE trial is expected to be released.
The FDA clarifies that the issuance of a EUA is different than an FDA approval. To issue a EUA, the agency evaluates the totality of available evidence and balances any known or potential risks with any known or potential benefits of the product.
Hence, due to the promising results of sotrovimab, the agency determined that it may effectively treat adults and certain pediatric patients with mild to moderate COVID-19.