Related Experiment Video
Updated: Jun 20, 2026
In Vitro Methods for Comparing Target Binding and CDC Induction Between Therapeutic Antibodies: Applications in Biosimilarity Analysis
Published on: May 4, 2017
Real-World Effectiveness and Safety of Tixagevimab-Cilgavimab: A Target Trial Emulation Study
Vincent Ka Chun Yan1, Yu Yang1, Eric Yuk Fai Wan1,2,3
1Centre for Safe Medication Practice and Research, Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China.
Background:
Immunocompromised individuals are at high risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and subsequent severe or fatal coronavirus disease 2019 (COVID-19), yet they have suboptimal responses to mRNA and inactivated COVID-19 vaccines. The efficacy of tixagevimab-cilgavimab in reducing symptomatic SARS-CoV-2 infection was demonstrated in phase III clinical trials. Nevertheless, real-world data on the effectiveness and safety of tixagevimab-cilgavimab remain limited.
Objective:
The aim was to evaluate the effectiveness and safety of tixagevimab-cilgavimab among immunocompromised individuals.
Methods:
Adults who were immunocompromised or receiving immunosuppressive therapies were included in this target trial emulation using territory-wide electronic health records in Hong Kong. A sequential trial emulation approach was adopted to compare effectiveness and safety outcomes between individuals who received tixagevimab-cilgavimab and individuals who did not.
Results:
A total of 746 tixagevimab-cilgavimab recipients and 2980 controls were included from 1 May 2022 to 30 November 2022. Tixagevimab-cilgavimab significantly reduced the risk of COVID-19 infection (hazard ratio [HR] 0.708, 95% confidence interval [CI] 0.527-0.951) during a median follow-up of 60 days. No significant difference was observed in the risk of COVID-19-related hospitalisation. Zero versus eight COVID-19 mortality cases and zero versus two severe COVID-19 cases were observed in tixagevimab-cilgavimab recipients and controls, respectively. Notably, significant risk reduction in COVID-19 infection was also observed among immunocompromised individuals who had been previously vaccinated with three or more doses of COVID-19 vaccine, or had no prior COVID-19 infection history.
Conclusions:
Tixagevimab-cilgavimab was effective in reducing COVID-19 infection among immunocompromised patients during the Omicron wave. Findings were consistent among individuals who previously received three or more doses of COVID-19 vaccine, or had no previous history of COVID-19 infection.
Insights
Tixagevimab-cilgavimab effectively reduced COVID-19 infection in immunocompromised individuals during the Omicron wave. This monoclonal antibody treatment showed significant protection, even in those with prior vaccinations or no infection history.
Area of Science:
- Immunology
- Infectious Diseases
- Pharmacology
Background:
- Immunocompromised individuals face high COVID-19 risks with poor vaccine response.
- Tixagevimab-cilgavimab showed efficacy in trials, but real-world data were limited.
Purpose of the Study:
- To evaluate the real-world effectiveness and safety of tixagevimab-cilgavimab in immunocompromised populations.
Main Methods:
- A territory-wide electronic health record analysis in Hong Kong.
- Sequential trial emulation comparing tixagevimab-cilgavimab recipients with controls.
Main Results:
- Tixagevimab-cilgavimab significantly reduced COVID-19 infection risk (HR 0.708).
- No significant difference in hospitalization risk; zero deaths in the treatment group versus eight in controls.
- Protection was observed in vaccinated individuals and those without prior infection.
Conclusions:
- Tixagevimab-cilgavimab demonstrated effectiveness in preventing COVID-19 infection among immunocompromised patients during the Omicron surge.
- Consistent benefits were noted across subgroups, including those with multiple vaccine doses or no prior infection history.
