Are we getting a lead on Omicron subvariant? Study says yes 

New preclinical authentic ‘live’ virus data from Washington University School of Medicine demonstrated that Evusheld (tixagevimab co-packaged with cilgavimab) retains potent neutralising activity against the emerging and highly transmissible Omicron SARS-CoV-2 BA.2 subvariant.¹ The data also showed that Evusheld retains activity against Omicron BA.1 and BA.1.1.1. The findings were reported online on bioRxiv. 

The data 

In vivo (live organism) data generated using mice infected with Omicron BA.1, BA.1.1 and BA.2 demonstrated that Evusheld significantly reduced the viral burden and limited inflammation in the lungs for all three subvariants.¹ SARS-CoV-2 viral load is associated with increased disease severity and mortality as well as post-Covid conditions (long Covid).^2,3

The mouse model 

The study used a transgenic mouse model to evaluate Evusheld in pre-exposure prophylaxis (prevention) of Covid-19, similar to how Evusheld is used in the clinic. These are the first in vivo data evaluating Evusheld’s efficacy against the Omicron variants versus previous in vitro neutralising activity assays in cultured cells. 

Official comments 

Michael Diamond, MD, PhD, The Herbert S. Gasser Professor, Departments of Medicine, Molecular Microbiology, Pathology & Immunology, Washington University, US, said: “These new in vivo mouse model data confirm previous in vitro neutralisation activity results for Evusheld against Omicron. The findings demonstrate that Evusheld was effective at protecting against infection in the lungs, a critical disease site for severe Covid-19, across all Omicron subvariants tested.” 

John Perez, Senior Vice President, Head of Late Development, Vaccines & Immune Therapies, AstraZeneca, said: “These important data show that Evusheld reduced viral burden and limited inflammation caused by Omicron. The findings further support Evusheld as a potential important option to help protect vulnerable patients such as the immunocompromised who could face poor outcomes if they were to become infected with Covid-19.” 

References 

1. Case, J et al. Resilience of S309 and AZD7442 monoclonal antibody treatments against infection by SARS-CoV-2 Omicron lineage strains. Available at  https://www.biorxiv.org/content/10.1101/2022.03.17.484787v1 [Last accessed March 2022]
2. Fajnzylber, J et al.  SARS-CoV-2 viral load is associated with increased disease severity and mortality. Available at https://www.nature.com/articles/s41467-020-19057-5/ [Last accessed March 2022}
3. Su Y, et al. Multiple early factors anticipate post-acute COVID-19 sequelae. Cell. 2022;185(5):881-895.e20.
4. FACT SHEET FOR HEALTHCARE PROVIDERS: EMERGENCY USE AUTHORIZATION FOR EVUSHELD™ (tixagevimab co-packaged with cilgavimab). Available at: https://www.fda.gov/media/154701/download [Last accessed: March 2022].