The FDA stops the use of antibodies that do not work against omicron
WASHINGTON – Covid-19 antibody drugs from Regeneron and Eli Lilly will no longer be used because they do not work against the omicron variant, which now accounts for almost all US infections, US health officials said on Monday.
The Food and Drug Administration said it was revoking the emergency authorization for both drugs, which were purchased by the federal government and have been administered to millions of Americans with Covid-19. If the drugs prove to be effective against future variants, the FDA said they could re-approve the use.
The regulatory move was expected because both drug manufacturers had said that the infusion drugs are less able to target omicron due to the mutations. Nevertheless, the federal action may trigger a pushback from some Republican governors who have continued to market the drugs against the advice of health experts.
Omicron̵[ads1]7;s resistance to the two leading monoclonal antibody drugs has upgraded the treatment book for Covid-19 in recent weeks.
Doctors have alternative therapies to combat early Covid-19 cases, including two new antiviral pills from Pfizer and Merck, but both are in short supply. An antibody drug from GlaxoSmithKline that remains effective is also in short supply.
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The FDA noted in its decision that omicron accounts for more than 99 percent of US infections, making it “highly unlikely” that the antibodies will help people now seeking treatment. The agency said limiting their use would also eliminate unnecessary drug side effects, including allergic reactions.
The US government temporarily stopped the distribution of the two drugs in late December, when omicron drove across the country to become the dominant variant. But officials resumed distribution following complaints from Republican governors, including Florida’s Ron DeSantis, who claimed the drugs continued to help some omicron patients.
DeSantis has strongly promoted antibody medicines as a signature part of his administration’s Covid-19 response, and has set up infusion sites and hailed them at news conferences, while opposing vaccine mandates and other public health measures. Texas Gov. Greg Abbott has also launched state-sponsored infusion sites.
The drugs are not a substitute for vaccination and are generally reserved for people who are most vulnerable, including the elderly, transplant recipients and those with conditions such as heart disease and diabetes.
Since the beginning of January, the US government has sent enough doses of the two antibodies to treat more than 300,000 patients.
Both Regeneron and Lilly previously announced that they were developing new antibodies that target omicron.
The move comes days after regulators expanded the use of remdesivir – the first drug approved for Covid-19 – to treat more patients.
On Friday, the FDA extended its antiviral approval to include adults and children with early Covid-19 who are at high risk of ending up in hospital. Remdesivir had previously been restricted to hospitalized patients.
An influential panel of federal experts had already recommended using the infused drug to try to ward off hospitalization. The same guidelines from the National Institutes of Health panel recommend the continued use of Lilly and Regeneron’s antibody drugs due to their reduced effectiveness against omicron.
Nevertheless, many hospitals will face challenges in increasing remdesivir treatments. The drug requires three consecutive IV infusions over three days, when used in patients who are not hospitalized. The time-consuming process will not be an option for many overcapacity hospitals facing staff shortages.
The FDA made its decision based on a study of 560 patients that showed a nearly 90 percent reduction in hospitalizations when remdesivir is given within seven days of symptoms. The study precedes the omicron variant, but like other antiviral agents, remdesivir is expected to maintain performance against the latest variant.
