Real-World Effectiveness of Sotrovimab for the Early Treatment of COVID-19: Evidence from the US National COVID Cohort Collaborative (N3C)

Background and Objective The coronavirus disease 2019 (COVID-19) pandemic has been an unprecedented healthcare crisis, one that threatened to overwhelm health systems and prompted an urgent need for early treatment options for patients with mild-to-moderate COVID-19 at high risk for progression to severe disease. Randomised clinical trials established the safety and efficacy of monoclonal antibodies (mAbs) early in the pandemic; in vitro data subsequently led to use of the mAbs being discontinued, without clear evidence on how these data were linked to outcomes. In this study, we describe and compare real-world outcomes for patients with mild-to-moderate COVID-19 at high risk for progression to severe COVID-19 treated with sotrovimab versus untreated patients. Methods Electronic health records from the National COVID Cohort Collaborative (N3C) were used to identify US patients (aged ≥ 12 years) diagnosed with COVID-19 (positive test or ICD-10: U07.1) in an ambulatory setting (27 September 2021-30 April 2022) who met Emergency Use Authorization (EUA) high-risk criteria. Patients receiving the mAb sotrovimab within 10 days of diagnosis were assigned to the sotrovimab cohort, with the day of infusion as the index date. Untreated patients (no evidence of early mAb treatment, prophylactic mAb or oral antiviral treatment) were assigned to the untreated cohort, with an imputed index date based on the time distribution between diagnosis and sotrovimab infusion in the sotrovimab cohort. The primary endpoint was hospitalisation or death (both all-cause) within 29 days of index, reported as descriptive rate and adjusted [via inverse probability of treatment weighting (IPTW)] odds ratio (OR) and 95% confidence interval (CI). Results Of nearly 2.9 million patients diagnosed with COVID-19 during the analysis period, 4992 met the criteria for the sotrovimab cohort, and 541,325 were included in the untreated cohort. Before weighting, significant differences were noted between the cohorts; for example, patients in the sotrovimab cohort were older (60 years versus 54 years), were more likely to be white (85% versus 75%) and met more EUA criteria (mean 3.1 versus 2.2) versus the untreated cohort. The proportions of patients with 29-day hospitalisation or death were 3.5% (176/4992) and 4.5% (24,163/541,325) in the sotrovimab and untreated cohorts, respectively (unadjusted OR: 0.78; 95% CI: 0.67, 0.91; p = 0.001). In adjusted analysis, sotrovimab was associated with a 25% reduction in the odds of hospitalisation or death compared with the untreated cohort (IPTW-adjusted OR: 0.75; 95% CI: 0.61, 0.92; p = 0.005). Conclusions Sotrovimab demonstrated clinical effectiveness in preventing severe outcomes (hospitalisation, mortality) in the period 27 September 2021-30 April 2022, which included Delta and Omicron BA.1 variants and an early surge of Omicron BA.2 variant.