Imdevimab

Imdevimab is not available as a standalone drug. It is only authorized for use in combination with Casirivimab as REGEN-COV. This combination was initially authorized for emergency use but is no longer effective against prevalent variants of COVID-19, including Omicron. It should not be administered. Because this medication is no longer in use, the following information is outdated as of February 16, 2025 and intended for historical reference only.

Usage

REGEN-COV was previously authorized for the treatment of mild to moderate COVID-19 in non-hospitalized adults and pediatric patients (12 years of age and older weighing at least 40 kg) with positive results of direct SARS-CoV-2 viral testing, and who are at high risk for progression to severe COVID-19, including hospitalization or death.

• Pharmacological classification: Monoclonal antibody (viral fusion inhibitor)

• Mechanism of action: Casirivimab and Imdevimab are monoclonal antibodies that bind to distinct, non-overlapping epitopes on the receptor-binding domain of the SARS-CoV-2 spike protein, thereby blocking the virus’s attachment and entry into human cells.

Alternate Names

• Combination with Casirivimab: REGEN-COV, Ronapreve
• Imdevimab alone: REGN10987

How It Works

• Pharmacodynamics: Casirivimab and Imdevimab work synergistically to neutralize SARS-CoV-2 by preventing viral entry into host cells. The combination was shown to reduce viral load and the risk of hospitalization or death in certain patient populations infected with early variants of COVID-19. This effect is no longer relevant given viral evolution.

• Pharmacokinetics: Both casirivimab and imdevimab exhibit linear pharmacokinetics following intravenous administration. Subcutaneous administration shows a similar pharmacokinetic profile with slightly lower peak concentrations but comparable overall exposure. Both antibodies are primarily eliminated via non-renal pathways, and metabolism by CYP enzymes is not anticipated.

• Mode of action: Receptor binding inhibition of SARS-CoV-2 spike protein.

• Elimination pathways: Primarily non-renal clearance. The exact metabolic pathways are not fully elucidated.

Dosage

The following dosage information is outdated and provided for historical reference only, as REGEN-COV is no longer effective or used:

Standard Dosage

Adults:

• 600 mg Casirivimab and 600 mg Imdevimab administered together as a single intravenous infusion or subcutaneous injection.

Children:

• Same as adult dosing for children 12 years of age and older weighing at least 40 kg.
• Not recommended for children younger than 12 years of age or weighing less than 40 kg.

Special Cases:

• Elderly Patients – No dose adjustment.
• Patients with Renal Impairment – No dose adjustment.
• Patients with Hepatic Dysfunction – Data limited; use with caution.
• Patients with Comorbid Conditions – No specific adjustments based on comorbidity; rather based on risk stratification for severe COVID-19.

Clinical Use Cases

REGEN-COV was not indicated for any of these settings.

• Intubation
• Surgical Procedures
• Mechanical Ventilation
• Intensive Care Unit (ICU) Use
• Emergency Situations

Dosage Adjustments

No dosage adjustments were necessary based on any of the following:

• renal/hepatic dysfunction
• metabolic disorders
• genetic polymorphisms

Side Effects

Common Side Effects

• Injection site reactions (pain, redness, swelling)

Rare but Serious Side Effects

• Severe allergic reactions (anaphylaxis)
• Infusion-related reactions

Long-Term Effects

Not fully established.

Adverse Drug Reactions (ADR)

• Anaphylaxis, severe infusion reactions.

Contraindications

• Hypersensitivity to casirivimab or imdevimab.

Drug Interactions

• Potential interference with the immune response to COVID-19 vaccines.

Pregnancy and Breastfeeding

Limited data available. It is unknown if REGEN-COV is present in human milk. Discuss with patient and conduct a risk/benefit assessment.

Drug Profile Summary

This information is outdated as of February 16, 2025:

• Mechanism of Action: Dual monoclonal antibodies binding to SARS-CoV-2 spike protein, blocking viral entry.
• Side Effects: Injection site reactions, allergic reactions.
• Contraindications: Hypersensitivity.
• Drug Interactions: Potential interference with COVID-19 vaccine response.
• Pregnancy & Breastfeeding: Limited data.
• Dosage: 600 mg Casirivimab + 600 mg Imdevimab, IV or SC.
• Monitoring Parameters: Monitor for allergic/infusion reactions during and after administration.

Popular Combinations

REGEN-COV was not used in combination with any other drugs for COVID-19.

Precautions

• Monitor for hypersensitivity reactions.

FAQs (Frequently Asked Questions)

Q1: What is the recommended dosage for Imdevimab?

A: Imdevimab is administered with casirivimab. The historical dosage was 600 mg of each, given via intravenous infusion or subcutaneous injection, but this medication is no longer in use.

Q2: What is the mechanism of action of Imdevimab?

A: Imdevimab is a monoclonal antibody that targets the spike protein of the SARS-CoV-2 virus. It was used in combination with casirivimab, as the two antibodies bound to different sites on the spike protein, preventing the virus from entering human cells. This is no longer effective.

Q3: Is Imdevimab safe for pregnant or breastfeeding women?

A: There was limited data on the use of Imdevimab (with casirivimab) in pregnant or breastfeeding women. Consultations with healthcare providers were necessary when considering its use.

Q4: Can Imdevimab be used in children?

A: Historically, the casirivimab/imdevimab combination was authorized for use in children 12 years and older weighing at least 40 kg, at the same dose as adults.

Q5: What are the common side effects of Imdevimab?

A: Common side effects included injection site reactions (pain, redness, swelling), and less commonly systemic reactions such as fever, chills, nausea, or headache.

Q6: Are there any contraindications to using Imdevimab?

A: The primary contraindication was a known hypersensitivity to imdevimab or casirivimab.

Q7: How is Imdevimab administered?

A: Imdevimab was administered intravenously or subcutaneously, always in conjunction with casirivimab.

Q8: Does Imdevimab interact with any other medications?

A: It has been suggested that Imdevimab, as part of the REGEN-COV cocktail, could potentially interfere with the body’s immune response to COVID-19 vaccines.

Q9: Why is Imdevimab no longer used?

A: Imdevimab and casirivimab are no longer effective against more recent circulating variants of SARS-CoV-2 such as Omicron. Therefore, they are no longer authorized for use and no longer distributed.