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Real-world effectiveness of casirivimab and imdevimab among patients diagnosed with COVID-19 in the ambulatory
Mohamed Hussein1, Wenhui Wei2, Vera Mastey2
1Regeneron Pharmaceuticals Inc, Tarrytown, New York, USA mohamed.hussein@regeneron.com.
Insights
Casirivimab and imdevimab (CAS+IMD) significantly reduced 30-day mortality or hospitalization for COVID-19 patients in real-world settings. This treatment demonstrated consistent effectiveness across various patient groups, including during the Delta variant surge.
Area of Science:
- Infectious Diseases
- Immunology
- Public Health
Background:
- The COVID-19 pandemic necessitated evaluating treatments like monoclonal antibodies for ambulatory patients.
- Casirivimab and imdevimab (CAS+IMD) were authorized for emergency use, but real-world effectiveness data were crucial.
- Assessing treatment effectiveness during the Delta-dominant period was important before the Omicron variant emerged.
Purpose of the Study:
- To evaluate the real-world effectiveness of CAS+IMD compared to no antibody treatment in ambulatory COVID-19 patients.
- To assess outcomes including mortality and hospitalization in a large, real-world cohort.
- To determine if CAS+IMD effectiveness varied across patient subgroups and during different epidemiological periods.
Main Methods:
- A retrospective cohort study utilizing the Komodo Health closed claims database.
- Matched analysis comparing 73,759 CAS+IMD treated patients with 310,688 untreated, eligible patients.
- Kaplan-Meier estimators and Cox proportional hazards models were used to analyze 30-day composite outcomes.
Main Results:
- CAS+IMD treatment was associated with a 60% lower risk of 30-day all-cause mortality or COVID-19 hospitalization (aHR 0.40).
- The effectiveness of CAS+IMD was consistent across subgroups, including vaccinated individuals and those diagnosed during the Delta-dominant period.
- No significant difference in effectiveness was observed across various risk factors and patient demographics.
Conclusions:
- Real-world data confirm the effectiveness of CAS+IMD in reducing mortality and hospitalization for COVID-19 patients.
- CAS+IMD demonstrated consistent efficacy across diverse patient populations and against prevalent variants like Delta.
- The findings support the use of CAS+IMD as a valuable therapeutic option in ambulatory COVID-19 care.
Objective:
To assess the real-world effectiveness of casirivimab and imdevimab (CAS+IMD) versus no COVID-19 antibody treatment among patients diagnosed with COVID-19 in the ambulatory setting, including patients diagnosed during the Delta-dominant period prior to Omicron emergence.
Design:
Retrospective cohort study.
Setting:
Komodo Health closed claims database.
Participants:
13 273 128 patients diagnosed with COVID-19 (December 2020 through September 2021) were treated with CAS+IMD or untreated but treatment eligible under the Emergency Use Authorization (EUA). Each treated patient was exact and propensity score matched without replacement to up to five untreated EUA-eligible patients.
Interventions:
CAS+IMD.
Primary And Secondary Outcome Measures:
Composite endpoint of 30-day all-cause mortality or COVID-19-related hospitalisation. Kaplan-Meier estimators were used to calculate outcome risks overall and across subgroups: age, COVID-19 vaccination status, immunocompromised status, and timing of diagnosis (December 2020 to June 2021, and July to September 2021). Cox proportional hazards models were used to estimate adjusted HRs (aHRs) and 95% CIs.
Results:
Among 75 159 CAS+IMD-treated and 1 670 338 EUA-eligible untreated patients, 73 759 treated patients were matched to 310 688 untreated patients; matched patients were ~50 years, ~60% were women and generally well balanced across risk factors. The 30-day risk of the composite outcome was 2.1% and 5.2% in the CAS+IMD-treated and CAS+IMD-untreated patients, respectively; equivalent to a 60% lower risk (aHR 0.40; 95% CI, 0.38 to 0.42). The effect of CAS+IMD was consistent across subgroups, including those who received a COVID-19 vaccine (aHR 0.48, 95% CI, 0.41 to 0.56), and those diagnosed during the Delta-dominant period (aHR 0.40, 95% CI, 0.38 to 0.42).
Conclusions:
The real-world effectiveness of CAS+IMD is consistent with the efficacy for reducing all-cause mortality or COVID-19-related hospitalisation reported in clinical trials. Effectiveness is maintained across patient subgroups, including those prone to breakthrough infections, and was effective against susceptible variants including Delta. .
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