Effectiveness of Regdanvimab at Preventing the Need for Oxygen Therapy in Patients with Mild-to-Moderate COVID-19: A Retrospective Cohort Study

Background: Monoclonal antibodies are a treatment option for patients with mild-to-moderate coronavirus disease (COVID-19). We investigated the effectiveness of regdanvimab, an anti-severe acute respiratory syndrome coronavirus-2 monoclonal antibody approved in Korea, in the treatment of patients with mild-to-moderate COVID-19. Materials and Methods: Medical records of patients who were admitted to a COVID-19 designated hospital during the study period of February 1 to June 31 and met the indications for administration of regdanvimab were reviewed to assess baseline characteristics and clinical outcomes such as supplemental oxygen requirements, mortality, and length of hospitalization. Multivariable logistic regression analysis was conducted to identify factors associated with requiring supplemental oxygen. Subgroup analysis was performed according to the presence of pneumonia confirmed on a chest X-ray. Results: Three hundred ninety-eight COVID-19 patients were included in the study, and 65 (16.3%) of them were administered regdanvimab. The proportion of patients requiring supplemental oxygen was significantly lower in the regdanvimab group than in the control group (6.2% vs. 20.1%, P = 0.007). There was no significant difference in mortality (0% vs. 1.5%, P >0.999) and the length of hospitalization (median: 10 days vs. 10 days, P = 0.267) between two groups. The multivariable analysis demonstrated that administration of regdanvimab was independently associated with lower oxygen supplement [odds ratio (OR): 0.20, 95% confidence interval (CI): 0.06 - 0.55, P = 0.004] after adjustment of potential risk factors related to supplemental oxygen including age, sex, chest X-ray abnormality, and underlying chronic kidney disease. Among the patients with pneumonia radiologically, administration of regdanvimab was also associated with lower risk of oxygen supplement (OR: 0.13, 95% CI: 0.02 - 0.46, P = 0.007). Conclusion: Regdanvimab use was related to lower need for supplemental oxygen in patients with mild-to-moderate COVID-19 for the indications for administration of regdanvimab.