Evusheld long-acting antibody combination retains neutralising activity against Omicron variant in independent FDA study

AstraZeneca's Evusheld (tixagevimab co-packaged with cilgavimab), a long-acting antibody combination for the prevention of COVID-19, retained neutralising activity against the Omicron SARS-CoV-2 variant (B.1.1.529), according to new preclinical data.

In this study, Evusheld's Inhibitory Concentration 50 (IC50), a measure of neutralising potency of an antibody, was 171 ng/ml and 277 ng/ml in two confirmatory tests, which is within the range of neutralising titres found in someone who has been previously infected with COVID-19. Evusheld’s IC50 for the original strain of SARS-CoV-2, previously referred to as the Wuhan strain, was approximately 1.3 ng/ml and 1.5 ng/ml, respectively.

The early data, generated by pseudovirus testing of the full Omicron variant spike against the combination of tixagevimab with cilgavimab, the antibodies that comprise Evusheld, add to the growing body of preclinical evidence demonstrating that Evusheld retains activity against all tested variants of concern to date.(1)

The study was performed independently by investigators at the US Food and Drug Administration (FDA), Center for Biologics Evaluation and Research. The work was supported by US government research funds.

Mene Pangalos, Executive Vice President, BioPharmaceuticals R&D, AstraZeneca, said: "This study shows Evusheld retains neutralisation activity against the Omicron variant. By combining two potent antibodies with different and complementary activities against the virus, Evusheld was designed to evade potential resistance with the emergence of new SARS-CoV-2 variants. Evusheld is the first long-acting antibody to receive emergency use authorisation in the US for pre-exposure prophylaxis of COVID-19, in addition to authorisations in other countries, and we are working with regulators on applications for the use of Evusheld in treating COVID-19."

The Omicron variant was not in circulation during the Evusheld clinical trials. The Company is continuing to collect further data to better understand the implications of this observation in clinical practice. Additional analyses to evaluate Evusheld against the Omicron variant are being conducted by AstraZeneca and third-party laboratories, with data anticipated very soon.

Evusheld received Emergency Use Authorization (EUA) in the US in December 2021 for pre-exposure prophylaxis (prevention) of COVID-19 in people with moderate to severe immune compromise due to a medical condition or immunosuppressive medications and who may not mount an adequate immune response to COVID-19 vaccination, as well as those individuals for whom COVID-19 vaccination is not recommended. The first doses are expected to become available within days.

About 2% of the global population is considered at increased risk of an inadequate response to a COVID-19 vaccine.(3,4) Emerging evidence indicates that protecting vulnerable populations from getting COVID-19 could help prevent viral evolution that is an important factor in the emergence of variants.(5)

Additionally, the TACKLE Phase III outpatient treatment trial of Evusheld showed it reduced the risk of developing severe COVID-19 or death (from any cause) by 50% compared to placebo in non-hospitalised patients with mild to moderate COVID-19 who had been symptomatic for seven days or less.(6)

About Evusheld

Evusheld, formerly known as AZD7442 is a combination of two LAABs - tixagevimab (AZD8895) and cilgavimab (AZD1061) - derived from B-cells donated by convalescent patients after SARS-CoV-2 virus. Discovered by Vanderbilt University Medical Center and licensed to AstraZeneca in June 2020, the human monoclonal antibodies bind to distinct sites on the SARS-CoV-2 spike protein(7) and were optimised by AstraZeneca with half-life extension and reduced Fc receptor and complement C1q binding. The half-life extension more than triples the durability of its action compared to conventional antibodies and could afford up to 12 months of protection from COVID-19 following a single administration;(8-10) data from the Phase III PROVENT trial show protection lasting at least six months.(11) The reduced Fc receptor binding aims to minimise the risk of antibody-dependent enhancement of disease - a phenomenon in which virus-specific antibodies promote, rather than inhibit, infection and/or disease.(12)

In December 2021, the U.S. Food and Drug Administration issued an Emergency Use Authorisation (EUA) for the use of Evusheld (tixagevimab co-packaged with cilgavimab) for the pre-exposure prophylaxis (prevention) of COVID-19. It is the only antibody authorised in the US to prevent COVID-19 symptoms before virus exposure. Evusheld is also authorised for emergency use for prevention of COVID-19 in several other countries.

In August 2021, AstraZeneca announced that Evusheld demonstrated a statistically significant reduction in the risk of developing symptomatic COVID-19 in the PROVENT trial; efficacy was 83% compared to placebo in a six-month analysis announced on 18 November 2021. In October 2021, AstraZeneca announced positive high-level results from the Evusheld TACKLE Phase III outpatient treatment trial.

Evusheld is also being studied as a potential treatment for hospitalised COVID-19 patients as part of the National Institute of Health’s ACTIV-3 trial and in an additional collaborator hospitalisation treatment trial.

Evusheld is being developed with support from the US government, including federal funds from the Department of Health and Human Services; Office of the Assistant Secretary for Preparedness and Response; Biomedical Advanced Research and Development Authority in partnership with the Department of Defense; Joint Program Executive Office for Chemical, Biological, Radiological and Nuclear Defense, under Contract No. W911QY-21-9-0001.

Under the terms of the licensing agreement with Vanderbilt, AstraZeneca will pay single-digit royalties on future net sales.

About AstraZeneca

AstraZeneca (LSE/STO/Nasdaq: AZN) is a global, science-led biopharmaceutical company that focuses on the discovery, development, and commercialisation of prescription medicines in Oncology, Rare Diseases, and BioPharmaceuticals, including Cardiovascular, Renal & Metabolism, and Respiratory & Immunology. Based in Cambridge, UK, AstraZeneca operates in over 100 countries and its innovative medicines are used by millions of patients worldwide.

1. ACTIV. National Center for Advancing Translational Sciences OpenData Portal. SARS-CoV-2 Variants & Therapeutics, All Variants Reported in vitro Therapeutic Activity. Available at: https://opendata.ncats.nih.gov/variant/activity [Last accessed: December 2021].
2. Neerukonda, S.N. et al. Establishment of a well-characterized SARS-CoV-2 lentiviral pseudovirus neutralization assay using 293T cells with stable expression of ACE2 and TMPRSS2. PLOS ONE March 10, 2021. Available at https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0248348 [Last accessed December 2021].
3. Oliver, S. Data and clinical considerations for additional doses in immunocompromised people. ACIP Meeting July 22, 2021. Available at: https://www.cdc.gov/vaccines/acip/meetings/downloads/slides-2021-07/07-COVID-Oliver-508.pdf. [Last accessed: December 2021].
4. AstraZeneca data on file.
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11. AstraZeneca news release. New analyses of two AZD7442 COVID-19 trials in high-risk populations confirm robust efficacy and long-term prevention. Available at: https://www.astrazeneca.com/media-centre/press-releases/2021/new-analyses-of-two-azd7442-covid-19-phase-iii-trials-in-high-risk-populations-confirm-robust-efficacy-and-long-term-prevention.html. [Last accessed: December 2021].
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