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A Rapid, Multiplex Dual Reporter IgG and IgM SARS-CoV-2 Neutralization Assay for a Multiplexed Bead-Based Flow Analysis System
Published on: April 6, 2021
Efficient in vitro assay for evaluating drug efficacy and synergy against emerging SARS-CoV-2 strains
Maximillian Woodall1, Samuel Ellis1, Shengyuan Zhang1
1UCL Great Ormond Street Institute of Child Health, London, United Kingdom.
Abstract:
Novel and repurposed antiviral drugs are available for the treatment of coronavirus disease 2019 (COVID-19). However, antiviral combinations may be more potent and lead to faster viral clearance, but the methods for screening antiviral combinations against respiratory viruses are not well established and labor-intensive. Here, we describe a time-efficient (72-96 h) and simple in vitro drug-sensitivity assay for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) using standard 96-well plates. We employ different synergy models (zero interaction potency, highest single agent, Loewe, Bliss) to determine the efficacy of antiviral therapies and synergistic combinations against ancestral and emerging clinical SARS-CoV-2 strains. We found that monotherapy of remdesivir, nirmatrelvir, and active metabolite of molnupiravir (EIDD-1931) demonstrated baseline EC50s within clinically achievable levels of 4.34 mg/L (CI: 3.74-4.94 mg/L), 1.25 mg/L (CI: 1.10-1.45 mg/L), and 0.25 mg/L (CI: 0.20-0.30 mg/L), respectively, against the ancestral SARS-CoV-2 strain. However, their efficacy varied against newer Omicron variants BA.1.1.15 and BA.2, particularly with the protease inhibitor nirmatrelvir. We also found that remdesivir and nirmatrelvir have a consistent, strong synergistic effect (Bliss synergy score >10) at clinically relevant drug concentrations (nirmatrelvir 0.25-1 mg/L with remdesivir 1-4 mg/L) across all SARS-CoV-2 strains tested. This method offers a practical tool that streamlines the identification of effective combination therapies and the detection of antiviral resistance. Our findings support the use of antiviral drug combinations targeting multiple viral components to enhance COVID-19 treatment efficacy, particularly in the context of emerging viral strains.
Insights
Developing effective COVID-19 treatments requires efficient screening of antiviral drug combinations. This study presents a new assay to identify synergistic antiviral therapies against SARS-CoV-2, including emerging variants.
Area of Science:
- Virology
- Pharmacology
- Drug Discovery
Background:
- Antiviral monotherapies exist for COVID-19, but combinations may offer enhanced efficacy.
- Current methods for screening antiviral combinations against respiratory viruses are often labor-intensive and not well-established.
- Identifying effective antiviral combinations is crucial for combating SARS-CoV-2, especially with emerging variants.
Purpose of the Study:
- To develop and validate a time-efficient in vitro drug-sensitivity assay for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).
- To evaluate the efficacy of antiviral monotherapies and combinations against ancestral and emerging SARS-CoV-2 strains.
- To identify synergistic antiviral combinations for improved COVID-19 treatment.
Main Methods:
- Development of a 72-96 hour in vitro drug-sensitivity assay using 96-well plates for SARS-CoV-2.
- Application of multiple synergy models (zero interaction potency, highest single agent, Loewe, Bliss) to assess drug efficacy.
- Testing of antiviral agents including remdesivir, nirmatrelvir, and EIDD-1931 against various SARS-CoV-2 strains.
Main Results:
- Monotherapy of remdesivir, nirmatrelvir, and EIDD-1931 showed baseline EC50s within clinically achievable levels against the ancestral strain.
- Antiviral efficacy varied against Omicron variants BA.1.1.15 and BA.2, with reduced effectiveness for nirmatrelvir.
- A consistent and strong synergistic effect was observed between remdesivir and nirmatrelvir across all tested SARS-CoV-2 strains.
Conclusions:
- The developed assay provides a practical tool for streamlining the identification of effective antiviral combination therapies against SARS-CoV-2.
- Antiviral drug combinations targeting multiple viral components are supported for enhanced COVID-19 treatment efficacy.
- The findings highlight the importance of combination therapies in overcoming antiviral resistance and addressing emerging viral strains.
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