The Medical Letter on Drugs and Therapeutics
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ISSUE
1635
Bamlanivimab and Etesevimab for Post-Exposure Prophylaxis of COVID-19
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Med Lett Drugs Ther. 2021 Oct 18;63(1635):163-4
Disclosures
Principal Faculty
  • Mark Abramowicz, M.D., President: no disclosure or potential conflict of interest to report
  • Jean-Marie Pflomm, Pharm.D., Editor in Chief: no disclosure or potential conflict of interest to report
  • Brinda M. Shah, Pharm.D., Consulting Editor: no disclosure or potential conflict of interest to report
Additional Contributor(s)
  • Michael Viscusi, Pharm.D., Associate Editor: no disclosure or potential conflict of interest to report
Objective(s)
Upon completion of this activity, the participant will be able to:
  1. Review the efficacy and safety of bamlanivimab and etesevimab together for post-exposure prophylaxis of COVID-19 infection and discuss the conditions that increase the risk for severe COVID-19 infection.
 Select a term to see related articles  bamlanivimab   casirivimab   COVID-19   etesevimab   imdevimab   REGEN-COV 
Revised 1/6/2022: The Variants paragraph has been updated.

In February 2021, the FDA issued an Emergency Use Authorization (EUA) for the investigational monoclonal antibodies bamlanivimab and etesevimab (Lilly) for use together to treat mild to moderate COVID-19 in persons ≥12 years old who weigh ≥40 kg and are at high risk of progression to severe disease or hospitalization.1 The FDA has now expanded this EUA to allow use of the antibodies together for post-exposure prophylaxis of COVID-19 in such persons if they are not fully vaccinated against COVID-19 or are unlikely to have an adequate immune response to full vaccination and have been in close contact with a SARS-CoV-2-infected individual or are likely to be exposed to SARS-CoV-2 in the setting of an institutional outbreak (see Table 1).2 Bamlanivimab plus etesevimab is the second monoclonal antibody combination to receive an EUA for post-exposure prophylaxis of COVID-19; casirivimab plus imdevimab (REGEN-COV) was authorized earlier.3

ELIGIBILITY — In May 2021, the FDA expanded the criteria by which a patient with COVID-19 can be considered at high risk for disease progression. All persons ≥12 years old who are overweight, pregnant, or have cardiovascular disease, hypertension, or chronic respiratory disease are now considered high-risk (see Table 2).4

CLINICAL STUDIES — In an unpublished double-blind trial (BLAZE-2 Part 1; summarized in the FDA Fact Sheet), 966 SARS-CoV-2-negative residents or staff of skilled nursing facilities where a confirmed SARS-CoV-2 infection occurred were randomized to receive a single dose of bamlanivimab 2800 mg (without etesevimab) or placebo.

The risk of symptomatic COVID-19 within 8 weeks of randomization, the primary endpoint, was significantly lower in patients who received bamlanivimab than in those who received placebo in both the overall population (8.5% vs 15.2%; number needed to treat [NNT] 15.1; adjusted OR 0.43 [95% CI 0.28-0.68]) and the prespecified subgroup of nursing facility residents (8.9% vs 22.5%; NNT 7.4; adjusted OR 0.20 [95% CI 0.08-0.49]). There were no deaths due to COVID-19 in the bamlanivimab group versus 4 in the placebo group.2,5

No data on the use of bamlanivimab plus etesevimab for post-exposure prophylaxis of COVID-19 are available. Because the combination has greater antiviral activity than bamlanivimab alone, the FDA presumed it to be effective based on the results of BLAZE-2 Part 1. No clinical trials have compared bamlanivimab plus etesevimab with casirivimab plus imdevimab.

ADVERSE EFFECTS — Infusion-related reactions and anaphylaxis have been reported with use of bamlanivimab plus etesevimab.

VARIANTS — Bamlanivimab plus etesevimab is not active against the Omicron variant of SARS-CoV-2. The combination retains activity against the Delta variant of the virus.2

DOSAGE AND ADMINISTRATION — The authorized dosage of bamlanivimab plus etesevimab for post-exposure prophylaxis is 700 mg of bamlanivimab and 1400 mg of etesevimab given as a single IV infusion as soon as possible after exposure to SARS-CoV-2. Patients should be monitored during the infusion and for at least 1 hour after its completion. Unlike REGEN-COV, bamlanivimab and etesevimab cannot be given by subcutaneous injection. Detailed instructions on preparation and administration of the antibodies are available in the FDA Fact Sheet.2

CONCLUSION — The FDA has authorized administration of the monoclonal antibodies bamlanivimab and etesevimab together for IV post-exposure prophylaxis of COVID-19 in certain high-risk persons. In a double-blind trial in SARS-CoV-2-negative residents and staff of nursing facilities in which a confirmed infection occurred, IV infusion of bamlanivimab alone significantly decreased the risk of symptomatic COVID-19 compared to placebo. The overall effectiveness of the two antibodies together for post-exposure prophylaxis remains to be determined. Bamlanivimab plus etesevimab retains efficacy against the Delta variant of SARS-CoV-2.

REFERENCES

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