Casirivimab and Imdevimab Benefits Hospitalized Seronegative COVID-19 Patients

New late-breaking data illuminate the specific efficacy of the combination monoclonal antibodies.

Combination monoclonal antibodies casirivimab and imdevimab was associated with a significant reduction in viral load among hospitalized, seronegative patients with COVID-19 who required low flow or no supplemental oxygen, according to findings from a late-breaking abstract presented at IDWeek 2021.

Presented by author Eleftherios Mylonakis, MD, PhD, Professor of Medicine & Molecular Microbiology and Immunology at Brown University, the new data showed patients treated with the previously emergency-authorized regimen also demonstrated clinically meaningful reductions in 28-day mortality and need for mechanical ventilation due to worsening COVID-19.

In an interview with Contagion during IDWeek, Mylonakis discussed the pooled cohort anaylsis, which included patients from trials phases 1-3 who were randomized to either placebo or casirivimab and imdevimab.

As Mylonakis noted, the most impactful finding from the assessment was in that the combination therapy was most beneficial for seronegative patients. Though the treatment has been in clinical COVID-19 practice for some time now—with Regeneron having been granted Emergency Use Authorization (EUA) for the combination in November 2020—these data can positively alter Mylonakis’ and colleagues’ approach to initiating therapy.

“Right away, it tells me that patients who come to the hospital, I can start grouping them from a clinical perspective to 2 different groups,” Mylonakis said. “Of course this is not new, but it is new in this trial.”