Related Experiment Video
Updated: Nov 19, 2025

Live Imaging and Quantification of Viral Infection in K18 hACE2 Transgenic Mice Using Reporter-Expressing Recombinant SARS-CoV-2
Published on: November 5, 2021
Host-directed therapies against early-lineage SARS-CoV-2 retain efficacy against B.1.1.7 variant
Ann-Kathrin Reuschl1, Lucy G Thorne1, Lorena Zuliani-Alvarez2,3,4,5
1Division of Infection and Immunity, University College London, London, WC1E 6BT, United Kingdom.
Abstract:
Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has resulted in millions of deaths worldwide and massive societal and economic burden. Recently, a new variant of SARS-CoV-2, known as B.1.1.7, was first detected in the United Kingdom and is spreading in several other countries, heightening public health concern and raising questions as to the resulting effectiveness of vaccines and therapeutic interventions. We and others previously identified host-directed therapies with antiviral efficacy against SARS-CoV-2 infection. Less prone to the development of therapy resistance, host-directed drugs represent promising therapeutic options to combat emerging viral variants as host genes possess a lower propensity to mutate compared to viral genes. Here, in the first study of the full-length B.1.1.7 variant virus , we find two host-directed drugs, plitidepsin (aplidin; inhibits translation elongation factor eEF1A) and ralimetinib (inhibits p38 MAP kinase cascade), as well as remdesivir, to possess similar antiviral activity against both the early-lineage SARS-CoV-2 and the B.1.1.7 variant, evaluated in both human gastrointestinal and lung epithelial cell lines. We find that plitidepsin is over an order of magnitude more potent than remdesivir against both viruses. These results highlight the importance of continued development of host-directed therapeutics to combat current and future coronavirus variant outbreaks.
Insights
Host-directed drugs plitidepsin and ralimetinib show antiviral activity against the SARS-CoV-2 B.1.1.7 variant. These therapies are promising for combating current and future coronavirus outbreaks.
Area of Science:
- Virology
- Drug Discovery
Background:
- Coronavirus disease 2019 (COVID-19), caused by SARS-CoV-2, has led to significant global mortality and socioeconomic impact.
- Emergence of SARS-CoV-2 variants, such as B.1.1.7, raises concerns about vaccine and therapeutic effectiveness.
- Host-directed therapies offer a promising strategy against viral variants due to the lower mutation rate of host genes compared to viral genes.
Approach:
- Evaluated antiviral activity of host-directed drugs against the full-length B.1.1.7 SARS-CoV-2 variant.
- Tested efficacy in human gastrointestinal and lung epithelial cell lines.
- Compared plitidepsin, ralimetinib, and remdesivir against both early-lineage SARS-CoV-2 and the B.1.1.7 variant.
Key Points:
- Plitidepsin (aplidin) and ralimetinib demonstrated antiviral activity against the B.1.1.7 variant, similar to their efficacy against early SARS-CoV-2 lineages.
- Plitidepsin showed over tenfold greater potency than remdesivir against both viral strains.
- Host-directed drugs maintain efficacy against emerging SARS-CoV-2 variants.
Conclusions:
- Host-directed therapeutics, including plitidepsin and ralimetinib, are effective against the SARS-CoV-2 B.1.1.7 variant.
- Continued development of host-directed therapies is crucial for addressing current and future coronavirus outbreaks.
- Plitidepsin represents a potent therapeutic candidate for COVID-19 treatment.

