Table 1. Efficacy of Monoclonal Antibodies and Antiviral Drugs against the Omicron/BA.2 Subvariant in Vitro.*.
| Monoclonal Antibody or Antiviral Drug | hCoV-19/Japan/UT-NCD1288-2N/2022 (Omicron/BA.2) | |
|---|---|---|
| Tested Value | Factor Increase as Compared with the Ancestral Strain | |
| Neutralization activity of monoclonal antibody† | ||
| LY-CoV016, etesevimab | >50,000 ng/ml | >2749 |
| LY-CoV555, bamlanivimab | >50,000 ng/ml | >10,661 |
| REGN10987, imdevimab | 68.65±8.84 ng/ml | 22.5 |
| REGN10933, casirivimab | 1666.19±771.77 ng/ml | 597.2 |
| COV2-2196, tixagevimab | 395.78±62.37 ng/ml | 206.1 |
| COV2-2130, cilgavimab | 4.44±2.72 ng/ml | 0.6 |
| S309, sotrovimab precursor | 1359.05±269.23 ng/ml | 49.7 |
| LY-CoV016 plus LY-CoV555 | >10,000 ng/ml | >794 |
| REGN10987 plus REGN10933 | 222.59±64.47 ng/ml | 63.1 |
| COV2-2196 plus COV2-2130 | 14.48±2.04 ng/ml | 4.2 |
| Viral susceptibility to drug‡ | ||
| GS-441524§ | 2.85±0.31 μM | 2.7 |
| EIDD-1931¶ | 0.67±0.22 μM | 1.3 |
| PF-07321332‖ | 6.76±0.69 μM | 1.9 |
Plus–minus values are means ±SD. The antibodies used in this analysis were produced in the authors’ laboratory and are not identical to the commercially available products. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant is denoted according to the World Health Organization labels for the Pango lineage.
The individual monoclonal antibodies were tested at a starting concentration of 50,000 ng per milliliter as a 50% focus reduction neutralization test (FRNT50) titer. The monoclonal antibody combinations were tested at a starting concentration of 10,000 ng per milliliter for each antibody. Shown is the factor increase in the FRNT50 titers of monoclonal antibodies against the omicron/BA.2 subvariant as compared with that against the ancestral strain, SARS-CoV-2/UT-NC002-1T/Human/2020/Tokyo (A).
In this category, the value is the 50% inhibitory concentration (IC50) of the mean micromole value of triplicate reactions. The factor increase in the IC50 of drugs against the omicron/BA.2 subvariant as compared with that against the ancestral strain, SARS-CoV-2/UT-NC002-1T/Human/2020/Tokyo (A), is shown.
GS-441524 is the main metabolite of remdesivir, an RNA-dependent RNA polymerase inhibitor.
EIDD-1931 is the active form of molnupiravir, an RNA-dependent RNA polymerase inhibitor.
PF-07321332 (also known as nirmatrelvir) is a protease inhibitor.