Impact of bamlanivimab monoclonal antibody treatment on hospitalization and mortality among non-hospitalized adults with SARS-CoV-2 infection

Bariola, J Ryan; McCreary, Erin K; Wadas, Richard J; Kip, Kevin E; Marroquin, Oscar C; Minnier, Tami; Koscumb, Stephen; Collins, Kevin; Schmidhofer, Mark; Shovel, Judith A; Wisniewski, Mary Kay; Sullivan, Colleen; Yealy, Donald M; Nace, David A; Huang, David T; Haidar, Ghady; Khadem, Tina; Linstrum, Kelsey; Seymour, Christopher W; Montgomery, Stephanie K; Angus, Derek C; Snyder, Graham M

BACKGROUND: Monoclonal antibody treatment may prevent complications of COVID-19. We sought to quantify the impact of bamlanivimab monoclonal antibody monotherapy on hospitalization and mortality among outpatients at high risk of COVID-19 complications. METHODS: In this observational study we compared outpatients who received bamlanivimab monoclonal antibody from December 9, 2020 to March 3, 2021 to non-treated patients with a positive polymerase chain reaction or antigen test for SARS-CoV-2 during the same period who were eligible for monoclonal antibody treatment. The primary outcome was 28-day hospitalization or all-cause mortality, and the secondary outcome was hospitalization or emergency department visit without hospitalization. The risk-adjusted odds of study outcomes comparing bamlanivimab treated and untreated patients was determined using 1:5 propensity matching and multivariable logistic regression. RESULTS: Among 232 patients receiving bamlanivimab matched with 1,160 comparator patients, the mean age was 67 years, 56% were female, and 196 (14%) of patients experienced hospitalization or mortality. After adjustment for propensity to receive treatment, bamlanivimab treatment was associated with a significantly reduced risk-adjusted odds of hospitalization or mortality within 28 days (OR 0.40, 95% confidence interval [95% CI] 0.24 to 0.69; p<.001). Bamlanivimab treatment was also associated with a significantly lower risk adjusted odds of hospitalization or emergency department visit without hospitalization (OR 0.54, 95% CI 0.35 to 0.82; p=.004). The results were most strongly associated with patients age 65 years and older. CONCLUSIONS: Bamlanivimab monoclonal antibody monotherapy was associated with reduced hospitalizations and mortality within 28 days among outpatients with mild-moderate COVID-19.