Bamlanivimab Plus Etesevimab in Mild or Moderate COVID-19

Quick Takes

  • Bamlanivimab and etesevimab are potent anti-spike neutralizing monoclonal antibodies to SARS-CoV-2 targeting different epitopes and used in the treatment of outpatients with mild to moderate COVID-19.
  • This phase 3 portion of the BLAZE-1 clinical trial including 1,035 participants provides compelling evidence of the effectiveness of this monoclonal antibody cocktail in improving the clinical status of patients with mild to moderate COVID-19.
  • Clinical benefit was seen across a number of outcomes, including mortality, hospitalization for COVID-19, and admission to the emergency department.

Study Questions:

Does combination bamlanivimab and etesevimab (neutralizing monoclonal antibody to severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2]) improve the clinical status of patients with mild to moderate coronavirus disease 2019 (COVID-19) compared to placebo?

Methods:

The BLAZE-1 study is a phase 2-3 randomized, double-blind, placebo-controlled, single-dose trial of bamlanivimab and etesevimab (neutralizing monoclonal antibodies to SARS-CoV-2) in outpatients (≥12 years of age) with mild to moderate COVID-19 and at least one risk factor for severe disease (age ≥65 years; body mass index ≥35 kg/m2, chronic kidney disease, diabetes mellitus, hypertension, cardiovascular disease, chronic respiratory disease, or immunosuppressed state). Participants were randomized to a single intravenous infusion of either a combination of 2800 mg of bamlanivimab and 2800 mg of etesevimab or placebo over a period of 1 hour. The primary outcome was the overall clinical status of the patients, defined as COVID-19–related hospitalization (acute care for ≥24 hours) or death from any cause by day 29.

Results:

A total of 1,035 patients were enrolled in the trial (mean age 54 years, with 31% aged ≥65 years, 52% women, with a median body mass index of 34 kg/m2). Over two thirds of participants (77.3%) had mild COVID-19 symptoms. Therapy was administered at a median of 4 days after the onset of symptoms. A total 11 of 518 patients (2.1%) in the bamlanivimab–etesevimab group, as compared with 36 of 517 patients (7.0%) in the placebo group met the primary outcome (absolute risk difference, -4.8%; 95% confidence interval, -7.4% to -2.3%). By day 29, none of the participants in the treatment arm died, while 10 in the placebo arm died (9 attributed to COVID-19). There was a dramatic reduction in viral load in the treatment arm compared to placebo, and the percentage of participants with a high viral load on day 7 was significantly higher in the placebo group compared to treatment (30% vs. 10%). Serious adverse events occurred in 1.4% of the bamlanivimab–etesevimab group and 1.0% in the placebo group.

Conclusions:

Administration of combination bamlanivimab and etesevimab to outpatients with mild to moderate COVID-19 significantly improved clinical status compared to placebo.

Perspective:

Bamlanivimab and etesevimab are potent anti-spike neutralizing monoclonal antibodies to SARS-CoV-2 targeting different epitopes and used in the treatment of outpatients with mild to moderate COVID-19. The findings of this phase 3 portion of the BLAZE-1 trial are in line with prior findings, which led to the Emergency Use Authorization by the Food and Drug Administration for the use of antibody therapy in decreasing the risk of progression to severe COVID-19. Prompt intervention with these therapies led to improvement across a range of outcomes in addition to rapidly decreasing SARS-CoV-2 viral load. Whether these monoclonal antibodies are effective across SARS-CoV-2 variants will be the next important question to address.

Clinical Topics: Prevention, Novel Agents, Hypertension

Keywords: Antibodies, Monoclonal, Body Mass Index, Coronavirus, COVID-19, Diabetes Mellitus, Hypertension, Immunocompromised Host, Outpatients, Primary Prevention, Renal Insufficiency, Chronic, Risk Factors, SARS-CoV-2, Spike Glycoprotein, Coronavirus, Viral Load


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