Bamlanivimab Monotherapy Improves Hospitalization, Mortality Outcomes in COVID-19

Antibodies attacking coronavirus particle
Antibodies attacking a coronavirus particle, illustration.
A team of investigators conducted a propensity-matched, observational study to assess outcomes in patients with COVID-19 receiving treatment with bamlanivimab monotherapy.

Among patients with mild to moderate COVID-19, treatment with the monoclonal antibody bamlanivimab was found to be associated with reduced risk of hospitalization and mortality within 28 days, with more favorable results in patients aged 65 years and older, according to study results published in Open Forum Infectious Diseases.

A team of investigators conducted a propensity-matched (1:5) observational study comparing monotherapy with or without bamlanivimab in patients who tested positive for SARS-CoV-2 infection via polymerase chain reaction assay or antigen testing to determine the effects of treatment on rates of hospitalization and mortality in outpatients who were at a high risk for COVID-19-related complications.

The primary outcome was 28-day hospitalization or all-cause mortality. The secondary outcome was hospitalization or emergency department (ED) visit without hospitalization.

A total of 232 patients treated with bamlanivimab were matched with 1160 patients who did not receive treatment (mean age, 67 years; 56% women). Of the patients who received bamlanivimab, 15 were hospitalized, 4 died, and 16 were treated in the ED without hospital admission. Of the comparator group not receiving bamlanivimab, 172 patients were hospitalized, 33 patients died, and 83 patients were treated in the ED without hospital admission.

The primary outcomes of hospitalization or mortality occurred in 6.9% of patients receiving bamlanivimab and in 15.5% of patients not receiving the monoclonal antibody treatment.   Secondary outcomes of hospitalization or ED visit occurred in 12.1% of patients receiving bamlanivimab and in 20.3% of patients not receiving the monoclonal antibody treatment.

Following risk adjustment, the odds of hospitalization or mortality (odds ratio [OR], 0.40) and ED visit without hospitalization (OR, 0.54) were lower among patients treated with bamlanivimab vs those not receiving treatment.

Limitations of the study include its observational design; the unreliability of assessing COVID-19 symptom presence, extent, and severity; unmeasured viral loads; and the lack of comparison to other available monoclonal antibodies used in the treatment of mild to moderate COVID-19.

“It will be critical to show similar results for the other available [monoclonal antibody] therapies and to define where each therapy may be best utilized, including possibly any continued role for bamlanivimab monotherapy,” the investigators noted.


Bariola JR, McCreary EK, Wadas RJ, et al. Impact of bamlanivimab monoclonal antibody treatment on hospitalization and mortality among non-hospitalized adults with SARS-CoV-2 infection. Open Forum Infect Dis. Published online May 17, 2021. doi:10.1093/ofid/ofab254