DeSantis, conservatives erupt over FDA pulling monoclonal antibodies shown to be ineffective against omicron

Some monoclonal antibody treatments are effective and free to high-risk coronavirus patients, but experts say the treatment alone cannot prevent the next surge. (Julie Yoon/The Washington Post) (WaPo)
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Few things inspire as much passion in the Republican base these days as alternative and often-unproven coronavirus treatments - even as many in the party continue to shun the most proven-effective treatment: vaccination. There has thus been a premium on politicians promoting these treatments or at least decrying scientists and government officials who question or reject their use.

In 2020, the prime example was hydroxychloroquine. In 2021, it was ivermectin. And early in 2022, it's monoclonal antibodies, which multiple early studies suggest are not effective against the now-dominant omicron variant.

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The Food and Drug Administration announced Monday that it would halt emergency-use authorizations for two monoclonal antibody therapies, one made by Regeneron Pharmaceuticals and one by Eli Lilly. At least with these monoclonal antibodies, unlike hydroxychloroquine and ivermectin, there was evidence they were once quite effective; that's just not the situation we find ourselves in at this point.

The FDA decision has led to a vehement outcry from some on the right, including the Republican who has most forcefully promoted monoclonal antibodies: Florida Gov. Ron DeSantis.

DeSantis said Monday that President Joe Biden "has forced medical pros to choose treating their patients or breaking the law."

The governor added Tuesday morning, "Without a shred of clinical data to support its decision, the Biden Administration has revoked the emergency use authorization for lifesaving monoclonal antibody treatments."

DeSantis's criticism has been cheered and echoed by many on the right, including Fox News's Sean Hannity.

Going quite a bit further, DeSantis spokeswoman Christina Pushaw on Monday night even promoted a claim by a conservative conspiracy theorist that "the FDA is trying to make it so that people in Florida die of Covid. They'll kill people to harm Republicans." By Tuesday morning, she promoted another baseless claim that the decision was made "so Fauci-Pfizer can get a few extra points in the stock market."

Retweets might not be endorsements, but those are certainly remarkable claims to circulate as a government spokesperson.

The first thing to note is that the use of treatments under emergency-use authorizations legally requires a determination that the benefits outweigh the known and potential risks. It's not just a matter of throwing anything at the problem that might help.

This was at the core of the FDA's decision to reverse its 2020 emergency authorization for hydroxychloroquine. Citing studies showing a lack of efficacy, the FDA said it was no longer "reasonable to believe that the known and potential benefits of these products outweigh their known and potential risks."

Indeed, the evidence for hydroxychloroquine's effectiveness had long been spotty at best, despite its promotion on the right, including by then-President Donald Trump. "What do you have to lose?" Trump said repeatedly. But that's not the calculation the FDA must make.

Similarly, despite DeSantis's claim that there is not "a shred of clinical data to support" the FDA's decision, there is significant data on the monoclonal antibodies' lack of effectiveness against the omicron variant in a laboratory setting.

As Nature reported more than a month ago, preliminary studies suggested that monoclonal antibody therapies, including the ones the FDA has now halted, showed virtually no efficacy against the omicron variant.

Here are some excerpts from one of the studies, which cites the Regeneron therapy (casirivimab and imdevimab) and the Eli Lilly therapy (bamlanivimab and etesevimab):

"Five out of six clinical antibodies that lost antiviral activity (Bamlanivimab, Etesevimab, Casirivimab, Imdevimab and Regdanvimab) no longer recognized Omicron infected cells. The other antibodies still bound to Omicron-infected cell. . . .

"We report that among nine [monoclonal antibodies] in clinical use or in development, six (Bamlanivimab, Etesevimab, Casirivimab, Imdevimab, Tixagevimab and Regdanvimab) were inactive against Omicron."

Another study conducted by Columbia University researchers along with the University of Hong Kong echoed those findings a week later. As Columbia University's Irving Medical Center summarized:

"The new study suggests that all of the therapies currently in use and most in development are much less effective against omicron, if they work at all.

"In neutralization studies with monoclonal antibodies, only one (Brii198 approved in China) maintained notable activity against omicron. A minor form of omicron is completely resistant to all antibodies in clinical use today. The authors note that omicron is now the most complete 'escapee' from neutralization that scientists have seen."

A more recent study, published in Nature last week, built upon the evidence. It stated that while some monoclonal antibodies had an effect, the ones used by Regeneron and Eli Lilly "completely lost neutralizing activity against" the omicron variant, and the combinations used by Regeneron and Eli Lilly "also lacked inhibitory capacity."

Some of these studies, of course, are a month old. And, indeed, there has already been controversy over the continued use (until Monday) of these specific monoclonal antibody treatments. The Department of Health and Human Services briefly halted their shipments on Dec. 23 before resuming them about a week later.

DeSantis had fought back, suggesting that the therapies could still be used against what remained of the delta variant. At the time, data from the Centers for Disease Control and Prevention showed that the delta variant still made up about one-quarter of infections in the United States; today, it accounts for a fraction of 1%.

"Therefore, it's highly unlikely that COVID-19 patients seeking care in the U.S. at this time are infected with a variant other than omicron, and these treatments are not authorized to be used at this time," the FDA said Monday.

But both DeSantis and Pushaw have also pushed back on the idea that the monoclonal antibody treatments don't work against the omicron variant. Pushaw earlier this month seemed to cite anecdotal evidence, saying that "there have been omicron cases treated with other [monoclonal antibodies] that showed significant improvement, contrary to the initial study that came out and apparently informed the now-reversed HHS policy."

It's certainly possible and even likely that omicron patients treated with these monoclonal antibodies showed significant improvement. But as with other unproven treatments that have been pushed using similar anecdotes, that doesn't mean the treatment was the reason for it. Most people hospitalized with the coronavirus, after all, will recover.

The Washington Post asked Pushaw on Tuesday morning what data there was supporting the continued use of the monoclonal antibodies for the omicron variant. She responded that the question had it "backwards."

"The onus should be on the FDA to provide the data to justify their decision to pull treatments off the market," Pushaw said.

She cited the most recent study cited above, which also stated, "Despite observing differences in neutralizing activity with certain [monoclonal antibodies], it remains to be determined how this finding translates into effects on clinical protection."

Again, this boils down to whether the evidence demonstrates the benefits continue to outweigh the known and potential drawbacks; the FDA decided it no longer does - at least right now.

A spokesman for the Department of Health and Human Services, Ian Sams, responded to DeSantis and other critics on Monday night.

"Why is Gov. DeSantis more interested in promoting medicines that don't work than urging people to take vaccines that do?" Sams asked rhetorically in a tweet.

He added in another tweet that the federal government is continuing to supply other, proven treatments to DeSantis's state.

"This week, we're providing Florida more than 34,000 additional doses of COVID treatments that **actually do work**," Sams said, adding that it was "the most doses of any state besides California and Texas."

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