Bamlanivimab for the Prevention of Hospitalizations and Emergency Department Visits in SARS-CoV-2–Positive Patients in a Regional Health Care System

Introduction: Bamlanivimab (LY-CoV555) was approved by Emergency Use Authorization by the United States Food and Drug Administration in the ambulatory setting to prevent hospitalizations and emergency department visits. We report a retrospective, case-control study of bamlanivimab use in a regional health care system. Methods: A retrospective case-control study for SARS-CoV-2-positive patients receiving bamlanivimab and matched controls between October 2020 and March 2021 was performed. End points included all-cause hospitalization, emergency department visits, and mortality. Results: No statistically significant difference was noted in all-cause hospitalization, emergency department visits, or mortality, including patients 65 years or older, body mass index of 35 or higher, diagnosis of diabetes mellitus, or cancer (high-risk patients). No difference was seen based on timing of bamlanivimab infusion relative to symptom onset or timing of infusion within the study period. Conclusions: Based on the evaluated endpoints, there was no benefit from bamlanivimab, regardless of when it was received in a patient's clinical course or when during the study period it was received. A lack of efficacy of monoclonal antibodies in patients infected with COVID-19 variants has been noted, but the impact of local variants on these results could not be assessed given a lack of available variant diagnostic tools. These findings do not support bamlanivimab for the prevention of hospitalization or emergency department visits for patients with mild to moderate SARS-CoV-2 infection.