A combination of two human neutralizing antibodies prevents SARS-CoV-2 infection in cynomolgus macaques

Med. 2022 Mar 11;3(3):188-203.e4. doi: 10.1016/j.medj.2022.01.004. Epub 2022 Feb 3.


Background: Human monoclonal antibody (mAb) treatments are promising for COVID-19 prevention or therapy. The pre-exposure prophylactic efficacy of neutralizing antibodies that are engineered with mutations to extend their persistence in human serum and the neutralizing antibody titer in serum required for protection against SARS-CoV-2 infection remain poorly characterized.

Methods: The Fc region of two neutralizing mAbs (COV2-2130 and COV2-2381) targeting non-overlapping epitopes on the receptor binding domain of SARS-CoV-2 spike protein was engineered to extend their persistence in humans and reduce interactions with Fc gamma receptors. We assessed protection by individual antibodies or a combination of the two antibodies (designated ADM03820) given prophylactically by an intravenous or intramuscular route in a non-human primate (NHP) model of SARS-CoV-2 infection.

Findings: Passive transfer of individual mAbs or ADM03820 conferred virological protection in the NHP respiratory tract in a dose-dependent manner, and ADM03820 potently neutralized SARS-CoV-2 variants of concern in vitro. We defined a protective serum-neutralizing antibody titer and concentration in NHPs for passively transferred human antibodies that acted by direct viral neutralization.

Conclusions: In summary, we demonstrate that neutralizing antibodies with extended half-life and lacking Fc-mediated effector functions are efficient for pre-exposure prophylaxis of SARS-CoV-2 infection in NHPs. These results support clinical development of ADM03820 for COVID-19 prevention.

Funding: This research was supported by a contract from the JPEO-CBRND (W911QY-20-9-003, 20-05); the Joint Sciences and Technology Office and Joint Program Executive Office (MCDC-16-01-002 JSTO, JPEO); a DARPA grant (HR0011-18-2-0001); an NIH grant (R01 AI157155); and the 2019 Future Insight Prize from Merck KGaA.

Keywords: SARS-CoV-2; aerosol; antibody therapeutics; cynomolgus macaques; human monoclonal antibody; neutralizing antibodies.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Antibodies, Monoclonal
  • Antibodies, Neutralizing / therapeutic use
  • COVID-19* / prevention & control
  • Humans
  • Macaca
  • SARS-CoV-2*
  • Spike Glycoprotein, Coronavirus


  • Antibodies, Monoclonal
  • Antibodies, Neutralizing
  • COV2-2130
  • COV2-2381
  • Spike Glycoprotein, Coronavirus
  • spike protein, SARS-CoV-2

Supplementary concepts

  • SARS-CoV-2 variants