Real-World Effectiveness of Bebtelovimab Versus Nirmatrelvir/Ritonavir in Outpatients with COVID-19

Introduction: This real-world study assessed the effectiveness of bebtelovimab (BEB) versus nirmatrelvir/ritonavir (NR) among outpatients with COVID-19 during the Omicron variant era. Methods: We conducted a cohort study evaluating patients treated with BEB or NR from February to August 2022 (study period). Follow-up began the day after treatment and continued for 30 days. Cohorts were constructed using de-identified electronic health record data from TriNetX Dataworks USA. The study assessed 30-day all-cause hospitalization or death (composite) using the risk difference (RD) and 95% confidence interval (95% CI). Results: Unmatched cohorts included 12,920 BEB- and 70,741 NR-treated patients. After exact matching on key baseline covariates (age > 65 years, immunocompromised, recent emergency department [ED] visit, and COVID-19 vaccination) and high-dimensional propensity score matching (1:1) on a broader set of covariates, 5827 patients were included in each cohort. BEB-treated patients were older and had more comorbidities compared to NR-treated patients prior to matching. After matching, baseline characteristics were well balanced. The cumulative incidence of the primary outcome (hospitalization or death) was 2.0% and 1.8% for BEB and NR, respectively (RD 0.2%; 95% CI - 0.3%, 0.7%). The upper bound of the RD 95% CI (0.7%) excluded the noninferiority margin (1.795%), demonstrating that BEB was not inferior to NR. The RDs of the secondary outcomes were (BEB vs NR): hospitalization (RD 0.1%; 95% CI - 0.4%, 0.6%); ED visit (RD 0.5%; 95% CI - 0.3%, 1.3%); and death (RD 0.09%; 95% CI - 0.003%, 0.2%). Results from subgroup, sensitivity, and linked analyses (EHR + claims + mortality data) were consistent with the main results. Conclusion: Treatment with BEB was not inferior to NR with respect to 30-day all-cause hospitalization or death. The risk of secondary outcomes was not different for patients treated with BEB compared to NR.