Mayo Clinic researchers have reported that the combination of Regeneron Pharmaceuticals’ casirivimab and imdevimab prevented hospitalisation in mild to moderate Covid-19 patients who are at high risk of disease progression, in an observational study.

Earlier this month, the US Food and Drug Administration (FDA) expanded the Emergency Use Authorization (EUA) for the monoclonal antibody cocktail to prevent Covid-19.

Funded and carried out by Mayo Clinic in partnership with artificial intelligence-powered health technology company nference, the observational study enrolled approximately 1,400 subjects.

Nearly 696 patients received the antibody cocktail between December 2020 and April 2021 while a control cohort of 696 subjects did not receive the treatment.

The status of the participants was analysed at 14, 21 and 28 days after the therapy.

The findings showed that the hospitalisation rates substantially reduced in the treatment arm at each of these time points.

Nearly 1.3% of subjects in the treatment arm were in the hospital versus 3.3% of those who did not receive the drug combination at day 14.

On day 21, 1.3% of treated participants were admitted to the hospital as against 4.2% in the untreated arm.

Furthermore, on day 28, 1.6% of subjects receiving the antibody combination treatment were hospitalised compared to 4.8% of subjects in the control group.

The Mayo Clinic noted that these data indicate that casirivimab plus imdevimab offered a 60% to 70% relative decrease in hospitalisation in treated subjects.

In addition, reduced rates of intensive care unit (ICU) admission and death were observed in subjects who received the treatment and were later admitted to the hospital.

Mayo Clinic infectious diseases specialist Raymund Razonable said: “Once again, this real-world study suggests that when patients who are at high risk due to a range of comorbidities contract a mild or moderate case of Covid-19, this combination of monoclonal injections gives them a chance of a no hospitalised recovery.”

Separately, another study at the Mayo Clinic, which enrolled 2,335 Covid-19 patients receiving bamlanivimab, demonstrated results consistent with the latest study.

Findings from the second study showed that the bamlanivimab treatment reduced hospitalisation rates in high-risk mild to moderate Covid-19 patients by 40% to 60%.