Regeneron is considering an emergency filing for its antibody cocktail REGEN-COV to protect people against COVID-19 after early trial results showed it conferred 100% protection against symptomatic infection. The results are based on a placebo-controlled trial involving 409 patients, where the cocktail of casirivimab and imdevimab was used as a passive vaccine for prevention of COVID-19 in people at high risk of infection.
In the trial, no cases of symptomatic infection were reported in the treatment arm of 186 patients, compared to eight cases in the placebo arm of 223 patients. There was also a 50% lower overall rate of infection, including both symptomatic and asymptomatic cases, with 23 in the placebo arm and ten in the treatment arm. Infections occurring with REGEN-COV therapy were all asymptomatic, with decreased peak virus levels and short duration of viral shedding.
In contrast, infections in the placebo group had, on average, more than 100-fold higher peak viral load. Infections in the treatment arm lasted no more than a week, while around 40% of infections in the placebo group lasted three to four weeks. No one in the REGEN-COV group had high viral loads compared with 62% in the placebo group.
Meanwhile, Eli Lilly reported that its antibody bamlanivimab when combined with etesevimab cut hospitalizations and deaths in high-risk patients recently diagnosed with COVID-19 by 70% compared with placebo. In the phase 3 BLAZE-1 trial involving 1,035 patients, there were 11 hospitalizations or deaths (2.1%) in patients taking the therapy compared with 36 of these events (7%) in those taking placebo. All 10 deaths occurred in the placebo group, with no deaths in patients taking bamlanivimab and etesevimab together.
Lilly also noted that the combination therapy demonstrated statistically significant improvements on all key secondary endpoints, providing strong evidence that the therapy reduced viral load and accelerated symptom resolution. Bamlanivimab monotherapy is already approved to treat high-risk patients with mild to moderate disease by the FDA under an Emergency Use Authorization. Lilly has filed a dossier asking for an EUA with the FDA for the combination therapy, which remains under review.
