COVID-19 and its variants are once again plaguing the country as we see case counts rise. The COVID-19 vaccine is critical in slowing the spread. In addition to the vaccine, once a person is infected with COVID-19 and is considered high-risk, the focus should turn to treatment using monoclonal antibodies (mAbs) and therapeutics. The FDA has announced it authorized an additional use for the COVID-19 monoclonal antibody therapeutic REGEN-COV (casirivimab and imdevimab). The REGEN-COV Emergency Use Authorization (EUA) has been expanded to include post-exposure prophylaxis.

The new authorization is for post-exposure prophylaxis use:

• In adult and pediatric individuals (12 years of age and older weighing at least 40 kg) for post-exposure prophylaxis of COVID-19 in individuals who are at high risk for progression to severe COVID-19, including hospitalization or death, and are:
• Not fully vaccinated or who are not expected to mount an adequate immune response to complete SARS-CoV-2 vaccination (for example, individuals with immunocompromising conditions including those taking immunosuppressive medications) and
  • Have been exposed to an individual infected with SARS-CoV-2 consistent with close contact criteria per CDC or
  • Who are at high risk of exposure to an individual infected with SARS-CoV-2 because of occurrence of COVID-19 infection in other individuals in the same institutional setting (for example, nursing homes or prisons).

This new authorized use is in addition to the prior authorization of REGEN-COV to treat non-hospitalized patients with mild to moderate COVID-19 in adult and pediatric patients, aged 12 and older, 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.

REGEN-COV is expected to be effective against circulating variants, including the Delta variant. It should be noted that post-exposure prophylaxis with REGEN-COV is not a substitute for vaccination against COVID-19, and REGEN-COV is not authorized for pre-exposure prophylaxis.

For both non-hospitalized treatment and post-exposure prophylaxis use, the authorized dose is 600 mg of casirivimab and 600 mg of imdevimab. For treatment of mild to moderate COVID-19, a single intravenous infusion is strongly recommended; however, subcutaneous injection may be an alternative if infusion is not feasible or would significantly delay treatment. For post-exposure prophylaxis, REGEN-COV may be administered as either subcutaneous injection or a single IV infusion. Please refer to the updated Fact Sheets for full details about dosing and administration.

The VDH COVID-19 Health Information Team also shared these additional notes:

1. In the updated Healthcare Providers Fact Sheet (reissued 7/30/2021), it notes that when REGEN-COV is used for postexposure prophylaxis, it should be used “as soon as possible following exposure to SARS-CoV-2.” The EUA does not specify a timeframe by which the drug must be used by. However, in the case of an immunocompetent person who has received the last dose of a two-dose vaccine series or a single dose of the J&J vaccine, the window of “not being fully vaccinated” would be the two weeks after the final vaccine dose. For an immunocompetent person, that period of time would appear to end when they are two weeks post completion of the vaccination series.In an immunocompromised person, even if they are fully vaccinated, the window of time could be longer (and potentially much longer) depending on how long they are considered immunocompromised, or how long it is felt the person is not able to develop an adequate immune response after complete SARS-CoV-2 vaccination. This may be more open to clinical interpretation/judgement.  
2. For postexposure prophylaxis, either an IV infusion or multiple subcutaneous (SC) injections of REGEN-COV can be used. This differs from the language for the outpatient treatment of patients with mild to moderate COVID-19 in which the EUA states that IV infusion is preferred, and that SC administration can be used if IV infusion is not feasible or would lead to a delay in treatment. When used for postexposure prophylaxis, this type of conditional language is not present—there is no preference for IV infusion or SC administration.
3. For people who have an ongoing exposure to SARS-CoV-2 and are not expected to mount an adequate immune response to complete vaccination, the initial dose of REGEN-COV (600 mg casirivimab and 600 mg imdevimab) may be followed by subsequent doses of casirivimab and imdevimab at half the initial dose every four weeks for the duration of the ongoing exposure. Thus, a subsequent dose of casirivimab 300 mg and imdevimab 300 mg given by either IV infusion or SC administration (with no preference in the route of administration) can be used every four weeks, if needed.
4. Patients who receive REGEN-COV by any route must be observed for one hour post drug administration for symptoms/signs of an allergic reaction.
5. Providers and/or facilities using REGEN-COV either for treatment of outpatients with mild to moderate COVID-19 who are at high risk for progression to severe illness OR for postexposure prophylaxis in accordance with the EUA must report usage to the National Healthcare Safety Network .
6. All medication errors and serious adverse events that occur during REGEN-COV use and are considered potentially related to the drug must be reported to FDA via a MedWatch report within seven calendar days from the onset of the event. A MedWatch report can be completed online or mailed to the FDA.

Additional Resources

The Health and Human Services Office of the Assistant Secretary for Preparedness and Response (HHS ASPR) has updated the CombatCOVID website with new resources to support providers in the fight against COVID-19.  

Included in the updates are:

• New testimonials from healthcare providers.
• Promising practice briefs that describe how health care leaders have improved access to mAb treatment for high-risk patients with COVID-19.
• A Facebook Live event on Thursday, August 5 at 12 PM EST featuring experts from ASPR and the CDC discussing COVID-19 variants. ​