Indications
As of January 24, 2022, according to the United States Food and Drug Association (FDA) fact-sheet for imdevimab, "due to the high frequency of the Omicron variant, imdevimab is not currently authorized for use in any U.S. region because of markedly reduced activity against the omicron variant. This drug may not be administered for treatment or post-exposure prevention of COVID-19 under the Emergency Use Authorization until further notice by the Agency." This article is to be used only for a historical review of the development and use of this drug.
Imdevimab is a monoclonal antibody (mAb) against spike protein (S) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that causes Coronavirus disease 2019 (COVID-19). It is one of the SARS-CoV-2 neutralizing antibodies proposed for use in the clinical management of COVID-19.[1] On 21st November 2020, imdevimab and casirivimab cocktail was authorized for emergency use by the United States Food and Drug Administration (FDA). These are investigational drugs not approved for any specific indication. FDA allowed these drugs only to be administered together. Imdevimab (REGN10987), and casirivimab (REGN10933) is also known as REGN-COV2 or Regeneron. The combination drug has been shown to decrease viral load and decrease the risk of hospitalization and emergency visits. It has also been shown to prevent virus-induced pathological sequelae when administered prophylactically or therapeutically in non-human primates.[1][2]
FDA authorized the drug cocktail to be used only in nonhospitalized patients who meet all three following criteria:
- Age ≥12 years and weight ≥40 kg
- Lab confirmed SARS-COV-2 infection
- Mild to moderate symptoms, which were at higher risk of progression to severe disease and/or hospitalization.[3][4]
High-risk patients include:
- Age ≥ 65 years
- Body mass index (BMI) ≥ 25 (If 12-17 years old - BMI ≥ 85th percentile for their age and gender)
- Pregnancy
- Chronic kidney disease
- Diabetes
- Immunosuppressive disease, currently on immunosuppressive treatment
- Cardiovascular disease (including congenital heart disease) or hypertension
- Chronic obstructive pulmonary disease (COPD), asthma or other chronic respiratory diseases
- Sickle cell disease
- Neurodevelopmental disorders (e.g., cerebral palsy)
- Medical device dependency (e.g., tracheostomy, gastrostomy, positive pressure ventilation [not related to COVID-19])
On June 3, 2021, the FDA updated the emergency use authorization (EUA) lowering the dosage of casirivimab and imdevimab to 600 mg each and option for subcutaneous (SQ) administration. There was another update on November 17, 2021, authorizing casirivimab and imdevimab (subcutaneously) for emergency use as post-exposure prophylaxis for COVID-19 in adults. It was recommended to be used for patients who are vaccinated but not expected to mount adequate immune response or who are not fully vaccinated.[5]
It is recommended to start the medication as soon as possible after a positive SARS-CoV-2 test and within 10 days of symptom onset. This is because active viral replication occurs between days 1 to 10 of symptoms, and these medications are unlikely to be beneficial later. Monoclonal antibodies are likely associated with worse clinical outcomes when administered to hospitalized COVID-19 patients requiring high flow oxygen or ventilator support. The imdevimab and casirivimab combination is not authorized in use for patients hospitalized or who require oxygen therapy for COVID-19. Viral load reductions with intravenous (IV) and SQ appear similar but data with SQ administration is limited.[5][6]
This being said, it is still reasonable to consider this drug combination in patients who test positive for SAR-COV-2 infection but are hospitalized due to some other indication. Patients or parents/caregivers have the option to accept or refuse this combination drug treatment. If treated with the drug cocktail, patients should continue to self-isolate and use infection control measures such as wear masks, social distance, disinfect surfaces, and maintain hand hygiene. Monoclonal antibodies provide rapid protection against infection, and protection can last for weeks to months. For patients receiving passive antibody therapy (e.g., mAbs), the recommendation is to defer COVID-19 vaccination for at least 90 days to avoid potential interference with the immune response to the vaccine.[7]
Please review the latest recommendations from the Centers for Disease Control and Prevention (CDC) and FDA on these medications as the indications and conditions for use are likely to be changed with the new variants of the virus emerging.