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REGEN-COV

casirivimab / imdevimab

Used for COVID-19

REGEN-COV was given emergency use authorization by the FDA to treat mild-to-moderate coronavirus disease 2019 (COVID-19) or prevent COVID-19 infections in people who were exposed to the virus. REGEN-COV is given through an injection, and there are specific criteria people need to meet in order to receive the medication.

Reviewed by:

Ashley Wong, PharmD

Cydnee Ng, PharmD

Last reviewed on January 22, 2022

Basics Side effects Pros & cons Pharmacist tips FAQs Warnings Dosage Prices Medicare

What is REGEN-COV?

What is REGEN-COV used for?

Treatment of mild-to-moderate COVID-19 infections in people aged 12 years and older who are at high risk of developing severe COVID-19
Prevention of COVID-19 infections in people aged 12 years and older who were exposed to the COVID-19 virus and are at high risk of developing severe COVID-19 (post-exposure prevention)

How REGEN-COV works

REGEN-COV is a combination of two monoclonal antibodies, casirivimab and imdevimab. Casirivimab and imdevimab bind to receptors on the COVID-19 virus, which blocks the virus from attaching to receptors in your body. This can help treat and prevent COVID-19 symptoms.

Drug Facts

Common BrandsREGEN-COV

Drug ClassMonoclonal antibody

Controlled Substance ClassificationNot a controlled medication

Generic StatusNo lower-cost generic available

AvailabilityNot FDA-approved yet

What are the side effects of REGEN-COV?

The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.

Common Side Effects

Reactions at the IV infusion site (e.g., pain, swelling, bleeding, bruising, infections)
Reactions at the injection site (e.g., redness, bruising, itchiness, infections)

Serious Side Effects

Contact your healthcare provider immediately if you experience any of the following.

Serious allergic reactions: rash, hives, dizziness, sweating, trouble breathing, changes in blood pressure or heart rate, chest pain, swelling of your lips, face, tongue, or throat
Worsening COVID-19 symptoms: fever, trouble breathing, changes in heart rate, weakness, confusion

Source: FDA

Pros and cons of REGEN-COV

Pros

One of the first treatments available for COVID-19

Can be used to treat or prevent COVID-19 infections

If using the medication for the treatment of COVID-19, you usually only need one injection.

Cons

Need to meet specific criteria in order to receive the medication

Can only be used in people aged 12 years and older

If using the medication for post-exposure prevention, you might need more than one dose.

Cannot be used for people with severe COVID-19

Pharmacist tips for REGEN-COV

REGEN-COV is administered by a healthcare provider. Your provider will monitor you for any side effects while you receive the medication and for at least 1 hour afterwards.

If you're receiving REGEN-COV through an IV infusion, the infusion can take 20 to 50 minutes. Your provider will decide how long your infusion will take.

If you're receiving REGEN-COV through an injection under your skin, the dose will be given in multiple injections in separate areas on your body, all around the same time.

If you're receiving REGEN-COV for post-exposure prevention, you might need additional doses of the medication for protection. Your provider will decide if multiple doses are needed and if so, they will be given to you once a month.

It's important that you continue to self-isolate and practice CDC-recommended safety measures to protect yourself and others from either getting or spreading the COVID-19 virus.

Receiving REGEN-COV for post-exposure prevention of COVID-19 isn't a replacement for vaccination against the virus. Talk to your provider about when the best time it is for you to get vaccinated against COVID-19 after you've received this medication.

Because REGEN-COV is still being studied, not all of the side effects are known and you can develop serious or unexpected side effects. Known side effects of the medication include allergic reactions, worsening COVID-19 symptoms, or reactions at the IV infusion or injection site. Contact your healthcare provider if develop any symptoms that concern you.

Frequently asked questions about REGEN-COV

Why was REGEN-COV's authorization for use taken away?

On January 24, 2022, the FDA revised the emergency use authorization for REGEN-COV due to the COVID-19 Omicron variant. The FDA stopped the medication's use in any area where COVID-19 exposure or infections are likely caused by a variant that isn't treatable by REGEN-COV. This medication isn't active against Omicron, which is currently the dominant variant in the U.S. Because of this, REGEN-COV is no longer authorized for use in any U.S. state, territory, or jurisdiction at this time. The FDA might revisit REGEN-COV's authorization in the future if COVID-19 infections are caused by a variant that can be treated with this medication.

Is REGEN-COV safe for children?

At this time, REGEN-COV isn't authorized for use in children under 12 years old or children weighing less than 88 lbs (40 kg). The medication is currently still being studied in teenagers and children, including those under 12 years old, in an ongoing clinical trial. The results of the study haven't been announced yet.

Is REGEN-COV safe for use during pregnancy?

It's not known if REGEN-COV is safe to use during pregnancy. There's a chance that the medication can transfer from you to your unborn baby, but it's not known if this is beneficial or harmful to your unborn baby. REGEN-COV should only be used during pregnancy if the benefits of taking the medication outweigh the risks. If you're pregnant, talk to your provider to see if this medication is safe for you.

Can I still receive REGEN-COV if I've been vaccinated against COVID-19?

Yes. If your provider determines that REGEN-COV is appropriate for you, you can still receive this medication even if you've been vaccinated against COVID-19.

Can I still get vaccinated for COVID-19 if I received REGEN-COV?

Yes. REGEN-COV shouldn't replace COVID-19 vaccination, but it's best to speak with your provider about when you can get vaccinated after receiving this medication. The Centers for Disease Control and Prevention (CDC) recommends waiting 90 days after receiving monoclonal antibodies for treatment and 30 days after receiving the antibodies for post-exposure prevention to get vaccinated against COVID-19. But there might be other factors that need to be considered before you get vaccinated.

Does REGEN-COV work against all of the COVID-19 variants?

There's a chance that REGEN-COV won't work against all COVID-19 variants (different versions of the virus due to changes in its DNA). Some COVID-19 variants might be resistant to REGEN-COV, which means the medication won't successfully treat the virus. If you tested positive for a particular COVID-19 variant (meaning you're infected with a particular version of the COVID-19 virus), let your provider know. They can determine if REGEN-COV would be an appropriate treatment option for you.

What are the criteria I need to meet in order to receive REGEN-COV for the treatment of COVID-19?

The FDA authorized REGEN-COV for the treatment of mild-to-moderate COVID-19 in people aged 12 years and older who are at high risk of developing severe COVID-19. This includes people who are at high risk of being hospitalized or dying. There are several factors that puts a person at high risk for developing severe COVID-19, including age, weight, and current medical conditions. It's best to speak with your provider so they can determine if you're at high risk of severe COVID-19 and if you'd qualify for this treatment.

What are the criteria I need to meet in order to receive REGEN-COV for post-exposure prevention of COVID-19?

The FDA authorized REGEN-COV for post-exposure prevention of COVID-19 in people aged 12 years and older who are at high risk of severe COVID-19. You can qualify for this treatment if you're not fully vaccinated against COVID-19 or if it's believed that your immune system won't build up a strong enough response to COVID-19 vaccinations and you've been exposed to someone with COVID-19 or are at high risk of being exposed to someone with COVID-19 (e.g., people living in nursing homes or a prison).

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What are the risks and warnings for REGEN-COV?

REGEN-COV can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.

Worsening of COVID-19 symptoms

Your COVID-19 symptoms can get worse after you receive REGEN-COV. You can experience symptoms such as fever, trouble breathing, tiredness, confusion, and changes in your heart rate or heart rhythm. Talk to your healthcare provider or get medical help if you develop any of these symptoms because they might require hospitalization. Because REGEN-COV is such a new treatment, it's unknown if these symptoms are caused by the medication or the natural development of the COVID-19 virus itself.

Not for use in people with severe COVID-19

Risk factors: Hospitalized due to COVID-19 | Requiring new or more oxygen treatment due to COVID-19

REGEN-COV might not be beneficial and might cause worse health outcomes for people with severe COVID-19 infections. This includes people who are hospitalized with COVID-19 and need help breathing (e.g., people on a ventilator or using high-flow oxygen). Because of this risk, REGEN-COV isn't authorized to be used in people who are hospitalized with COVID-19 or people who require new or more oxygen treatment because of their COVID-19 infection.

REGEN-COV dosage forms

Typical dosing for REGEN-COV

REGEN-COV is administered by a healthcare provider. The typical dose of REGEN-COV is 600 mg/600 mg (casirivimab/imdevimab) given through an injection in your veins (intravenous or IV infusion) or under your skin (subcutaneous injection). If you're taking REGEN-COV to treat COVID-19, it's recommended that the medication be given through an IV infusion rather than through an injection under your skin.

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