Phase III trial of REGEN-COV shows positive data in prevention of COVID-19.- Regeneron Pharma

Regeneron Pharmaceuticals announced positive initial results from an ongoing Phase III clinical trial evaluating REGEN-COV (casirivimab and imdevimab antibody cocktail) used as a passive vaccine for the prevention of COVID-19 in people at high risk of infection (due to household exposure to a COVID-19 patient). The trial is being run jointly with the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH). An exploratory analysis was conducted on the first approximately 400 evaluable individuals enrolled in the trial, who were randomized to receive passive vaccination with REGEN-COV (1,200 mg via subcutaneous injections) or placebo. Results included: 1.Passive vaccination with REGEN-COV2 resulted in 100% prevention of symptomatic infection (8/223 placebo vs. 0/186 REGEN-COV), and approximately 50% lower overall rates of infection (symptomatic and asymptomatic) (23/223 placebo vs. 10/186 REGEN-COV). 2. The lower number of infections occurring with REGEN-COV therapy were all asymptomatic, with decreased peak virus levels and short duration of viral shedding. i.Infections occurring in the placebo group had, on average, more than 100-fold higher peak viral load.ii. Infections in the REGEN-COV group lasted no more than 1 week, while approximately 40% of infections in the placebo group lasted 3-4 weeks.iii. No infected individuals in the REGEN-COV group had high viral loads (>10^4 copies/mL) compared to 62% of the infected placebo group (13/21 placebo vs. 0/9 REGEN-COV). REGEN-COV was associated with lower disease burden: i.Fewer total viral shedding weeks (44 weeks placebo vs. 9 weeks REGEN-COV).ii. Fewer total high viral shedding weeks (>10^4 copies/mL) (22 weeks placebo vs. 0 weeks REGEN-COV).iii. Fewer total symptomatic weeks (18 weeks placebo vs. 0 weeks REGEN-COV). In the safety assessment, adverse events occurred more frequently in participants on placebo (18% placebo vs. 12% REGEN-COV); this difference was driven by the increased rate of SARS-CoV-2 infections in the placebo group. In the placebo group, there was one death and one COVID-19-related hospitalization; there were no deaths or COVID-19 hospitalizations in the treatment group. Injection site reactions occurred at a rate of approximately 2% in both treatment and placebo groups.