Monoclonal antibodies: What are they and how do they treat COVID-19?
The federal government recently announced it will increase the average weekly pace of shipments of monoclonal antibody (mAb) therapy for COVID-19 by 50%. As the pandemic continues, here are some questions healthcare organizations and patients should have answers to regarding this treatment option:
What are monoclonal antibodies and how do they work?
Monoclonal antibodies are antibodies made in a laboratory to fight a specific infection and are similar to the ones naturally produced in the body. The mAb therapies being used to treat COVID-19 target the spike protein of SARS-CoV-2 virus—the virus which causes COVID-19—blocking it from attaching to and entering the body’s cells.
Since November 2020, the U.S. Food and Drug Administration (FDA) has issued emergency use authorization (EUA) for multiple mAb therapies, including casirivimab plus imdevimab, sotrovimab, and bamlanivimab plus etesevimab.
While mAbs are now receiving more attention, they have been developed to treat and prevent other viruses in the past, such as Ebola.
As referenced by Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, research indicates that monoclonal antibodies may reduce the risk of COVID-19 hospitalization or death by 70 to 85%.
Who can be treated with monoclonal antibody therapy?
Use of mAbs, which are delivered through an IV, is authorized for the outpatient treatment of high-risk patients who either test positive for COVID-19 or have been exposed to COVID-19. Conditions and risk factors for patients at high risk for progression to severe COVID-19 and/or hospitalization include being older than 65, pregnancy, obesity, diabetes, chronic kidney disease, immunosuppression, cardiovascular disease, hypertension, sickle cell disease, neurodevelopment disorders and chronic lung disease. To have mAb therapy, patients must be over 12 years of age, weigh approximately 88 pounds or more and receive a referral from their provider.
Patients are not eligible for monoclonal antibody treatment if they are hospitalized due to COVID-19, require oxygen therapy due to COVID-19 or are on chronic oxygen therapy due to an underlying comorbidity.
To maximize effectiveness, mAbs should be given as soon as possible and within 10 days of the onset of symptoms.
Where can monoclonal antibody therapy be administered? What does it cost?
Medical practices must meet two requirements to administer mAbs: they must have the ability to activate the emergency medical system (EMS) as well as have access to medications to treat any severe reactions to the therapy. Distribution locations can be found on the U.S. Department of Health & Human Services (HHS) website.
In terms of cost, there is no cost to patients for the mAb product with Medicare and Medicaid. Medicare is also covering the cost to administer mAbs while Medicaid coverage for administration varies by state. On the commercial side, many large insurers are waiving some or all costs of infusions, so beneficiaries should check what their specific plans cover.
What are the risks of this treatment?
Infusion-related and allergic reactions include fever, nausea, irregular heartbeat and anaphylaxis. However, across two clinical trials, researchers found that monoclonal antibody treatment did not pose serious concerns: 1.4% of participants who received mAbs experienced Severe Adverse Reactions (SAEs) compared to 4% in placebo groups.
Like other infusion treatments, patients may also experience side effects like bruising of the skin, soreness and possible infection at the infusion site.
Is vaccination status a factor?
The Centers for Disease Control and Prevention (CDC) reports that being fully vaccinated against COVID-19 should not affect treatment decisions or timing of mAb treatment.
For unvaccinated patients who receive mAb therapy for a COVID-19 infection, the CDC recommends deferring vaccination until at least 90 days after mAb treatment.
What can medical practices do if they cannot administer the treatment themselves?
Time is of the essence with monoclonal antibodies. If a patient tests positive for COVID-19 or has been exposed to the virus and is a good candidate for mAb therapy, clinicians should reach out as soon as possible to discuss treatment options and make referrals.
The FDA has made clear that monoclonal antibodies are not a substitute for vaccination against COVID-19. Healthcare organizations can continue supporting their patients during the pandemic by educating them on the benefits and safety of COVID-19 vaccines and other preventative measures like masks, well-ventilated spaces, physical distancing and hand hygiene.
For more information on monoclonal antibodies, visit the HHS Combat COVID website.