Aug. 26, 2021 -- The FDA authorized monoclonal antibody drugs from the companies Regeneron and Eli Lilly in November 2020, but only recently have they attracted more attention as the Delta variant of the virus that causes COVID-19 surges across the U.S.

Clinical trials show that Regeneron’s monoclonal antibody treatment, a combination of two antibodies called casirivimab and imdevimab, reduces COVID-19-related hospitalization or deaths in high-risk patients by about 70%. And when given to an exposed person -- like someone living with an infected person -- monoclonal antibodies reduced their risk of developing an infection with symptoms by 80%.

“As hospitalizations go up nationwide, we have a therapy here that can mitigate that,” says William Fales, MD, medical director of the Michigan Department of Health and Human Services Division of EMS and Trauma. Getting monoclonal antibodies is one of “the best things you can do once you’re positive.”

Whether you’ve just tested positive or been exposed, monoclonal antibodies could help you and your loved ones stave off COVID-19. Here’s what you need to know.

How do they work?

Monoclonal antibodies are like the antibodies your body makes to fight viruses and other bugs, but they are made in the labs of pharmaceutical companies, like Regeneron. They’re designed to target the coronavirus spike protein. When the antibodies bind to the spike protein, they block the virus from entering your body’s cells, says Lindsay Petty, MD, an infectious disease doctor at the University of Michigan. If the virus can’t enter cells, it can’t make copies of itself and continue spreading within the body.

If a person is already sick, that means monoclonal antibodies prevent them from having severe symptoms that require hospitalization. If someone has been exposed, monoclonal antibodies can fend off the virus to prevent them from becoming sick in the first place.

Monoclonal antibodies were first authorized as an IV and are most commonly given at infusion centers. But a recent study showed they can also be given as an shot into the belly when an IV isn’t as accessible.

As the coronavirus mutates, monoclonal antibodies targeted for the original form of the virus may become less helpful. The U.S. government stopped distribution of Lilly’s monoclonal antibodies, bamlanivimab and etesevimab, after evidence showed they weren’t as effective against new variants of the virus. But other monoclonal antibodies remain helpful.

“Consumers should know that Regeneron [does work] against the Delta variant,” says David Wohl, MD, an infectious disease expert at the University of North Carolina.

How is it different from a vaccine?

A vaccine helps stimulate and prepare your immune system to respond if or when you are exposed to the virus, Petty says. “Your immune system is ready to create all these antibodies before they are needed.”

Monoclonal antibodies boost the immune system after you are already sick, speeding up your immune response to prevent COVID-19 from getting worse. “But a vaccine does this much easier and much better,” Petty says.

You can think of monoclonal antibodies as guided missiles that target and neutralize the virus, Fales says. But they don't stick around. While monoclonal antibodies are effective for about a month, they are long gone 6 months later, when a vaccine still offers significant protection.

When should you get them?

Timing is critical with monoclonal antibodies, according to Petty. The earlier they are given, the more effective they are at treating or preventing COVID-19.

They are really most effective within the first 4 to 5 days of symptoms, according to Wohl.

The best thing you can do, Petty says, is get tested as soon as you notice any possible symptoms. And as soon as you test positive, get in touch with your doctor about your interest in monoclonal antibodies either for yourself or others you’ve been in contact with who are at high risk.

Monoclonal antibodies can’t be given after 10 days of symptoms, Petty says. So, “a delay [in testing or seeking out treatment] could mean there’s not a treatment available.”

Who’s eligible for monoclonal antibodies?

There are two authorized uses for monoclonal antibodies: To treat or stop COVID-19’s progression in a high-risk person who tests positive, and to prevent COVID-19 in a high-risk person who’s been exposed.

To qualify for the treatment of mild or moderate disease, a person must test positive for COVID-19, have had symptoms for fewer than 10 days, not be hospitalized or on oxygen because of COVID-19, and be at high risk for the disease to get worse.

The FDA has recently expanded what it means to be high-risk for severe COVID-19, Fales says. Many more people now may qualify for monoclonal antibodies, including those with high blood pressure, heart disease, a body mass index (BMI) higher than 30, an autoimmune disorder, people taking immunosuppressant drugs, and people who are pregnant.

The same groups of high-risk people can get monoclonal antibodies to prevent COVID-19 if they have been exposed. If you or a loved one is immunocompromised, based on CDC guidelines, and spent 15 minutes or longer within 6 feet of someone who tested positive, you likely qualify for a preventive monoclonal antibodies infusion.

As for vaccinated folks, there’s no evidence that the treatment doesn’t work or is harmful to them, Fales says. But vaccinated people have a lower risk of getting COVID-19 when exposed, and of developing severe COVID-19 if they do become infected, so they don’t generally qualify for monoclonal antibodies for prevention. 

In certain cases, a vaccinated person may be eligible to get monoclonal antibodies, Fales says: If they are immunocompromised due to age or another condition and might not build a robust immune response to the vaccine that would protect them in case of exposure, or if they become infected with COVID-19 and their symptoms become significant.

How much does treatment cost?

The U.S. government has bought doses of Regeneron’s monoclonal antibodies, which are free to patients who qualify. But depending on your insurance coverage, you may be charged for the cost of giving the treatment.

How do I get monoclonal antibodies?

Since monoclonal antibodies are primarily given in infusion centers, not doctors’ offices, getting access isn’t always straightforward. And many doctors still aren’t very experienced with the treatment, Petty says.

Still, if you or a loved one has tested positive or been exposed and you think you might qualify for treatment, the first step is to contact your doctor. If they are familiar with monoclonal antibodies, they can help you get the treatment and bypass a lot of the work for you, Petty says.

If your doctor isn’t familiar with monoclonal antibodies, you should still talk to them about your interest in treatment. You can use websites from the Department of Health and Human Services and Infusion Centers of America to find a nearby treatment site.

Many of these sites require a referral from a doctor, Fales says. If you don’t have a referral, they often can help you get one if you call ahead, whether through your doctor, a doctor at the infusion center, a telehealth consultation, or a local urgent care clinic.

Can I help relatives in assisted living get it?

If you believe that a relative in a residential facility -- like a nursing home, assisted living facility, long-term care home, or prison -- has COVID-19 or has been exposed, the first thing you should do is have a conversation with the medical leadership at the facility.

Fales has partnered Michigan-based paramedics with several nursing homes in the state to have monoclonal antibodies delivered to these facilities when there’s an outbreak. It’s also possible for long-term care pharmacies to get monoclonal antibodies to administer in-house. If the medical leadership doesn’t appear to be aware of the treatment, you can use the same websites to find the nearest infusion center and begin coordinating treatment with it.

It's a good idea, Fales says, to find out where monoclonal antibodies are offered in your area, and perhaps talk with your doctor or a high-risk loved one’s doctor about how to get them, to be prepared. The faster you can get the treatment, the more likely it will help.

WebMD Health News

Sources

Infectious Diseases Society of America: “Monoclonal Antibodies.”

The New England Journal of Medicine: “Subcutaneous REGEN-COV Antibody Combination to Prevent Covid-19.”

William Fales, MD, medical director, Michigan Department of Health and Human Services, Division of EMS and Trauma.

Lindsay Petty, MD, infectious disease doctor, University of Michigan.

Eli Lilly: “Emergency Use Authorization (EUA) for the Treatment of COVID-19.”

FDA: “Emergency Use Authorization (EUA) for bamlanivimab 700mg IV Center for Drug Evaluation and Research (CDER) Memorandum on Fact Sheet Update.”

David Wohl, MD, infectious disease expert, University of North Carolina.

CDC: “People with Certain Medical Conditions.”

Regeneron: “REGEN-COV for COVID-19: Emergency Use Authorization (EUA).”

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