- The FDA approved another monoclonal antibody drug for coronavirus therapy — this time it’s Regeneron’s dual antibody cocktail.
- Casirivimab and imdevimab received an Emergency Use Authorization for the treatment of mild to moderate patients who might be at risk of developing severe COVID-19.
- The drugs aren’t meant to treat COVID-19 patients who are already hospitalized or receiving oxygen.
After granting Eli Lilly’s bamlanivimab an Emergency Use Authorization (EUA) a few weeks ago, the FDA issued a similar approval for a breakthrough coronavirus drug from the same class. Bamlanivimab is a monoclonal antibody drug that works solely against COVID-19. The drug delivers a concentrated dose of potent neutralizing antibodies to the body. The antibodies can then block the virus from infecting cells and speed up recovery in patients. However, monoclonal antibodies aren’t going to work in all situations. They have to be administered quickly after a positive COVID-19 diagnosis and have not been found to be effective once complications arise.
The same rules apply for Regeneron’s casirivimab and imdevimab. These are two antibodies that are part of the same treatment, the dual monoclonal antibody combo that showed effectiveness in some trials. President Trump also received the combo during his COVID-19 case in late September, and it’s believed to have helped him recover so quickly.
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Like bamlanivimab, casirivimab and imdevimab have to be administered intravenously, and the drugs are given simultaneously. The Regeneron treatment is suitable for mild to moderate COVID-19 in adults and pediatric patients who are 12 years or older, weighing at least 88 pounds. The treatment is recommended to patients at risk of developing severe COVID-19, including people over 65 or those suffering from certain chronic conditions.
The FDA explained that casirivimab and imdevimab were shown to reduce COVID-19 hospitalization or emergency room visits in patients at high risk for disease progression compared to the group of patients who received placebo. Casirivimab and imdevimab reduced viral loads in patients on day 7 compared to the placebo. But the most important evidence that the combo was effective concerns hospital visits within 28 days after treatment. Only 3% of the patients who received Regeneron’s cocktail had to visit hospitals, compared to 9% for the placebo group.
Also of note, the FDA says that the treatment is not authorized for patients who are already hospitalized due to COVID-19 or require oxygen therapy due to COVID-19. “Monoclonal antibodies, such as casirivimab and imdevimab, may be associated with worse clinical outcomes when administered to hospitalized patients with COVID-19 requiring high flow oxygen or mechanical ventilation,” the announcement reads.
The EUA rules are similar for the Eli Lilly and Regeneron drugs. It’s likely that other monoclonal antibodies that will be approved for COVID-19 treatment will have to respect the same general guidelines.
While monoclonal antibodies aren’t the perfect treatment for COVID-19, they can still help patients recover faster and avoid hospital visits if treatment is given early after a positive COVID-19 test. The drugs can also help “alleviate the burden on our health care system,” FDA Commissioner Stephen M. Hahn said in a statement. The US has been breaking its own coronavirus records for weeks when it comes to daily cases and hospitalizations. The US reached nearly 200,000 new cases each day on Friday and Saturday, as well as more than 83,000 hospitalizations as of Saturday.
The FDA says that possible side effects of casirivimab and imdevimab include anaphylaxis and infusion-related reactions, fever, chills, hives, itching, and flushing.
Regeneron said in a press release that the company would have 300,000 doses ready by the end of January. The US government will provide these 300,000 doses at no cost to patients, although the initial supply will hardly be enough to meet the demand.