Subcutaneous REGEN-COV Antibody Combination to Prevent Covid-19

Covid-19 Phase 3 Prevention Trial Team

Research output: Contribution to journalArticlepeer-review

316 Scopus citations

Abstract

BACKGROUND: REGEN-COV (previously known as REGN-COV2), a combination of the monoclonal antibodies casirivimab and imdevimab, has been shown to markedly reduce the risk of hospitalization or death among high-risk persons with coronavirus disease 2019 (Covid-19). Whether subcutaneous REGEN-COV prevents severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and subsequent Covid-19 in persons at high risk for infection because of household exposure to a person with SARS-CoV-2 infection is unknown.

METHODS: We randomly assigned, in a 1:1 ratio, participants (≥12 years of age) who were enrolled within 96 hours after a household contact received a diagnosis of SARS-CoV-2 infection to receive a total dose of 1200 mg of REGEN-COV or matching placebo administered by means of subcutaneous injection. At the time of randomization, participants were stratified according to the results of the local diagnostic assay for SARS-CoV-2 and according to age. The primary efficacy end point was the development of symptomatic SARS-CoV-2 infection through day 28 in participants who did not have SARS-CoV-2 infection (as measured by reverse-transcriptase-quantitative polymerase-chain-reaction assay) or previous immunity (seronegativity).

RESULTS: Symptomatic SARS-CoV-2 infection developed in 11 of 753 participants in the REGEN-COV group (1.5%) and in 59 of 752 participants in the placebo group (7.8%) (relative risk reduction [1 minus the relative risk], 81.4%; P<0.001). In weeks 2 to 4, a total of 2 of 753 participants in the REGEN-COV group (0.3%) and 27 of 752 participants in the placebo group (3.6%) had symptomatic SARS-CoV-2 infection (relative risk reduction, 92.6%). REGEN-COV also prevented symptomatic and asymptomatic infections overall (relative risk reduction, 66.4%). Among symptomatic infected participants, the median time to resolution of symptoms was 2 weeks shorter with REGEN-COV than with placebo (1.2 weeks and 3.2 weeks, respectively), and the duration of a high viral load (>104 copies per milliliter) was shorter (0.4 weeks and 1.3 weeks, respectively). No dose-limiting toxic effects of REGEN-COV were noted.

CONCLUSIONS: Subcutaneous REGEN-COV prevented symptomatic Covid-19 and asymptomatic SARS-CoV-2 infection in previously uninfected household contacts of infected persons. Among the participants who became infected, REGEN-COV reduced the duration of symptomatic disease and the duration of a high viral load. (Funded by Regeneron Pharmaceuticals and others; ClinicalTrials.gov number, NCT04452318.).

Original languageEnglish (US)
Pages (from-to)1184-1195
Number of pages12
JournalThe New England journal of medicine
Volume385
Issue number13
DOIs
StatePublished - Sep 23 2021
Externally publishedYes

Bibliographical note

Copyright © 2021 Massachusetts Medical Society.

Keywords

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Antibodies, Monoclonal, Humanized/therapeutic use
  • Asymptomatic Diseases
  • COVID-19/drug therapy
  • Child
  • Double-Blind Method
  • Drug Combinations
  • Female
  • Humans
  • Incidence
  • Injections, Subcutaneous
  • Male
  • Middle Aged
  • Patient Acuity
  • SARS-CoV-2
  • Viral Load
  • Young Adult

PubMed: MeSH publication types

  • Journal Article
  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural

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