Regeneron Pharmaceuticals has reported encouraging initial data from an ongoing Phase I/II/III clinical trial of its antibody cocktail, casirivimab and imdevimab, for treating hospitalised Covid-19 patients needing low-flow oxygen.
The cocktail of two monoclonal antibodies – Casirivimab and imdevimab – can potentially block infectivity of SARS-CoV-2, the virus that causes Covid-19.
The analysis was conducted on patients enrolled in the Phase I/II segments of the trial, which assessed safety, anti-viral activity and clinical outcomes with the antibody cocktail for Covid-19.
In the trial, patients randomised in 1:1:1 ratio were given a one-time infusion of 8,000mg or 2,400mg (high and low dose) of the antibody combination, or placebo.
The trial’s primary clinical objective was to analyse whether the combination provided sufficient efficacy in these participants to go ahead with the trial (futility analysis).
Data showed seronegative patients receiving the treatment had a decreased incidence of death or mechanical ventilation, thus passing the futility analysis.
Post-hoc analysis results showed that death risk or receiving mechanical ventilation was lowered by nearly half, one week after the combination treatment.
On day seven, the cocktail lowered the time-weighted average daily viral load by -0.54 log10copies/mL in the seronegative patients and by day 11, it was -0.63 log10copies/mL.
While in seropositive patients, as estimated, the antibody cocktail had limited clinical and virologic benefit.
Regeneron president and chief scientific officer George Yancopoulos said: “These preliminary results in hospitalised patients, as well as data from the previously announced outpatient trial, indicate that antibodies produced by a patient’s own immune response are important to control Covid-19 infection.
“In this trial, patients who had not yet mounted their own immune response had much higher viral loads and much worse clinical outcomes; for example in the placebo group, seronegative patients were almost three-times more likely to die compared to seropositive patients.”
In October, Regeneron Pharmaceuticals reported positive results from an ongoing Phase II/III seamless trial of investigational antibody cocktail, REGN-COV2, in the Covid-19 outpatient setting.