Monoclonal antibody treatments could cut COVID-19 hospitalizations significantly - but doctors aren't using their full supply

• The FDA has authorized two monoclonal antibody treatments for COVID-19.
• Scientists think the drugs could help reduce hospitalizations.
• But Moncef Slaoui, the chief advisor of Operation Warp Speed, told CNBC that states are only using 5% to 20% of their available supply.
• That's likely because doctors have a window of just 10 days to administer monoclonal antibodies, and the logistics of the infusions are challenging.

As the US rejoiced over the results of two coronavirus vaccine trials in November, a significant drug advancement slipped by relatively unnoticed.

On November 9, the Food and Drug Administration green-lit the first monoclonal antibody treatment for COVID-19. Eli Lilly's bamlanivimab was authorized for use among non-hospitalized patients with mild to moderate COVID-19. Those at high risk of severe disease due to age or a medical condition are eligible to get it.

The FDA authorized a second monoclonal antibody therapy less than two weeks later: a two-drug cocktail called REGEN-COV2 from biotech company Regeneron. Again, only patients with mild to moderate COVID-19 who are at high risk of severe disease are eligible.

By the time the authorizations were announced, Operation Warp Speed had already purchased thousands of doses of each drug. The government bought between 70,000 and 300,000 doses of Regeneron's antibody cocktail (depending on how much the company could manufacture for $450 million) in July and 300,000 doses of bamlanivimab in October.

But getting the drugs to sick patients is challenging.

The therapies have to be administered within 10 days of symptoms first appearing, but given testing lags and strains on healthcare services, that window can pass quickly.

"Antibody therapies always work best the earliest they're given," Arturo Casadevall, an immunologist at Johns Hopkins Bloomberg School of Public Health, told Business Insider. "This has been known for 130 years."

Plus, the treatments' newness may still give some doctors pause.

"For better or worse, some people might be more willing to pull that trigger and others might want to hold back because they're still waiting for that perfect dataset to come out that shows exactly the risk and the benefit," Rodney Rohde, chair of the Texas State University clinical laboratory science program, told Business Insider.

By mid-December, states were only using 5% to 20% of their monoclonal antibody supply - around 65,000 doses per week on average - Warp Speed chief advisor Moncef Slaoui told CNBC.

"That's way too low," Rohde said. "It needs to at least be pushing 50% to 60%."

A sweet spot to administer the drug

The FDA has only authorized a handful of COVID-19 treatments so far. One of those, convalescent plasma, involves treating sick patients with the blood of those who've already recovered, since that blood contains antibodies that help fight the virus.

Monoclonal antibodies function similarly, but they can be designed to target specific coronavirus proteins. Regeneron's cocktail, for instance, targets the spike protein that helps the virus attach to and invade cells.

"You can kind of think of them as smart bombs," Rohde said. "They're actually probably better than convalescent plasma, because sometimes you don't know the amount [of antibodies] you're getting and how strong they actually bind."

With monoclonal antibodies, he added, "you're creating a better mousetrap" - but only if the drug is administered right away.

"If you can get those antibodies infused into a person in the first several days when that virus is trying to crank out brand-new baby virus, and you can get those neutralized and tied up, that limits that infection from amplifying," Rohde said. "If you're behind the eight-ball and you start trying to treat someone with severe COVID illness and they're just massively infected, it may not be very helpful."

In a study of 465 non-hospitalized COVID-19 patients with mild to moderate symptoms, only 3% of those who got bamlanivimab went to the hospital, compared to 10% of those who got a placebo. Regeneron's cocktail yielded similar results.

That suggests monoclonal antibodies could reduce hospitalizations by up to 70%. Once people are sick enough to need hospitalization, though, other treatments are needed.

"The reason it doesn't work very well with severe disease is because severe disease is caused by an inflammatory response and these antibodies work as antivirals," Casadevall said. "What the antibody is doing is interfering with the virus. The virus is causing inflammation, so if you are able to treat early, you head off the disease."

Donald Trump, Chris Christie, and Ben Carson got monocolonal antibodies

Monoclonal antibody drugs gained public attention this fall when they were administered to some high-level public officials, including President Donald Trump, former New Jersey Gov. Chris Christie, and Housing and Urban Development Secretary Ben Carson.

But Rohde said many patients may not know to ask for them. Others may assume the treatment is too expensive.

The US government is currently offering the Regeneron and Eli Lilly therapies at no cost to the public, but monoclonal antibodies have a reputation for being pricey: A 20-year study found that FDA-approved monoclonal antibody treatments for other illnesses cost around $97,000 per year, on average.

But scientists anticipate that as the treatments get more widely used, supply will become a mounting issue. Monoclonal antibodies are grown in cells taken from hamster ovaries, then extracted and purified.

"I don't think that this is easily scalable for the world," Casadevall said. "To get these things into liquid, into a vial is just difficult."

Plus, manufacturers are accustomed to producing similar antibody drugs in small batches.

"The industry generally is used to having to deliver much lower doses because we tend to use antibodies for rheumatology and for cancer," Casadevall said - a far cry, he added, from the "truly industrial amounts that are needed to combat an epidemic."

Hospitals also aren't necessarily equipped to administer them to patients - or may be too strained to do so.

"You have to get the infusions, which means you have to put the patient somewhere and that takes about an hour. Then you have to observe them for about an hour," Rohde said. "You really have to be set up to do that."

Dr. Princy Kumar, who helps coordinate the monoclonal antibody program at Medstar Health in the Washington, DC, region, told NPR that the biggest challenge was getting people to go to the hospital for the treatment.

"As they are infectious, they can't just hail a ride-sharing app and show up at the infusion center," Kumar said. "And many of them are reluctant to put a family member, who has to ride with them in the car, at risk."

Antibody cocktails may represent the future of coronavirus treatment

Scientists are still optimistic about monoclonal antibody therapy for COVID-19, though, since it's unlikely the coronavirus will ever fully disappear in the US, and not every person will be eligible to get vaccinated.

"If they can't get the vaccine and they can't build their own immunity due to autoimmune issues, then at least with monoclonal therapies, you might be able to prevent serious illness in these types of people," Rohde said.

Monoclonal antibodies may also help some people avoid hospitalization before vaccines become widely available, he added.

"It's really an important opportunity to kind of bridge treatments until we get that vaccine in place and get enough people immunized," Rohde said. "People are going to continue to get sick and move into severe illness over the coming months."

One possible concern, however, is that monoclonal antibodies could lose their efficacy if significantly different coronavirus strains emerge.

"If the virus changes that little piece that the monoclonals bind to, then obviously they lose efficacy," Casadevall said.

It's unknown, for example, whether the therapies work against the new variant spreading in the UK and other countries. But since antibody cocktails have more than one target, Casadevall said, they may be effective against multiple strains.

"These antibodies will find a niche in the arsenal as long as we have COVID around," he said. "My hope is that the companies continue to produce them and to make even better cocktails."