Monoclonal antibodies can lower COVID-19 hospitalisation risk

A study has found that monoclonal antibodies (mAbs) reduced the risk of hospitalisation or death by 39 percent when given within two days of individuals testing positive for COVID-19 (coronavirus).

This investigation compared patients who were given these treatments to those who were eligible, but did not receive it. Immunocompromised patients experienced further reduced risk, the researchers noted. The level of risk infection was determined at 28 days.

In the trial, researchers from the University of Pittsburgh Medical Center evaluated 2,571 patients treated with monoclonal antibodies. These were matched with data from 5,135 eligible COVID-19 patients who did not receive the treatment. 

Trial methodology

Single-dose intravenous doses of the mAb treatment were given with bamlanivimab, bamlanivimab–etesevimab, sotrovimab, bebtelovimab, or intravenous or subcutaneous casirivimab–imdevimab.

The findings showed that the overall risk for hospitalisation or death at 28 days was 4.6 percent in treated patients compared with 7.6 percent in non-treated control patients.

Reducing severity of COVID-19 with monoclonal antibodies

Between 2020 and 2022, the US Food and Drug Administration (FDA) granted emergency use authorisation to five different COVID-19 monoclonal antibody treatments. These treatments were shown to reduce COVID-19 viral load. Later they demonstrated ability to decrease rates of hospitalisation and death in some at-risk patients.

The authorised treatments have since been suspended or revoked by the FDA due to in vitro evidence of evolving loss of efficacy against new COVID-19 variants. However, this action was taken without the availability of randomised trials or real-world data.

In the present study, the evolving real-world effectiveness of early mAb treatment was determined for the COVID-19 outpatients who were treated over nearly two years. According to the authors, the results indicate that throughout the pandemic, early treatment with monoclonal antibodies significantly reduced severity of COVID-19.

Currently there is no FDA-approved monoclonal antibody treatments for COVID-19 outpatients, so these findings are important, the authors emphasised.

The research was published in Annals of Internal Medicine.