Add Post-Exposure Prophylaxis to Regen-COV Protocols

You'll hear buzz about using casirivimab/imdevimab (Regen-COV) to PREVENT COVID-19...especially as cases continue to rise.

You already use this monoclonal antibody combo to TREAT mild to moderate COVID-19 in outpatients age 12 or older at high risk of severe illness.

Many patients are considered at high risk, such as those with diabetes...age 65 or older...or even with a BMI over 25.

Now casirivimab/imdevimab is authorized for PROPHYLAXIS in these SAME high-risk patients who are exposed and not fully vaccinated...or vaccinated, but not expected to mount an adequate immune response.

For example, consider casirivimab/imdevimab after an exposure if a patient with diabetes finished their COVID-19 vaccine series less than 14 days ago...or if a vaccinated transplant patient is exposed.

"Exposure" is being within 6 ft of a person with COVID-19 for 15 min total. This may change as we learn more about the Delta variant.

Explain that giving casirivimab/imdevimab within 96 hours of exposure may prevent COVID-19 in about 1 in 18 UNvaccinated patients at 28 days. It's currently effective against SARS-CoV-2 variants of concern.

Plus post-exposure prophylaxis seems to shorten symptoms by about 2 weeks if patients still get sick.

Ensure your protocols are updated to reflect this new use.

Give the same dose for post-exposure prophylaxis as for treatment... 600 mg/600 mg IV over 20 to 50 minutes or as 4 separate 2.5 mL subcutaneous injections given at one time.

For prevention, use either route. But for treatment, continue to save subcutaneous for when IV isn't feasible or would cause delays.

Monitor for rare hypersensitivity reactions for at least 1 hour after the dose...same as you'd do when giving for treatment.

Watch for errors during med prep.

For example, there are 10 mL vials COMBINING casirivimab and imdevimab...but also INDIVIDUAL components in 2.5 mL or 11.1 mL vials and "dose packs" that may not have the drug name on the vial.

Recommend deferring COVID-19 vaccination for at least 90 days after casirivimab/imdevimab...it may interfere with the vaccine immune response.

Get our algorithm, "Mabs" for COVID-19, for eligibility criteria. And for a deeper dive into the evidence, use our chart, Treatments of Interest for COVID-19.

Key References

  • www.fda.gov/media/145611/download (8-27-21)
  • www.covid19treatmentguidelines.nih.gov/therapies/statement-on-casirivimab-plus-imdevimab-as-pep/ (8-27-21)
  • N Engl J Med Published online Aug 4, 2021; doi:10.1056/NEJMoa2109682
  • www.cdc.gov/coronavirus/2019-ncov/variants/variant-info.html (8-27-21)
Hospital Pharmacist's Letter. September 2021, No. 370902



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