Regeneron COVID-19 Antibody Cocktail Proves Effective in Clinical Trial
By Rick Pezzullo—
Tarrytown-based Regeneron Pharmaceuticals, Inc. announced Monday positive data from a Phase 3 trial of recently infected asymptomatic COVID-19 patients evaluating an antibody cocktail.
The study showed REGEN-COV™ (casirivimab with imdevimab) reduced the overall risk of progressing to symptomatic COVID-19 by 31% (primary endpoint), and by 76% after the third day. The trial also demonstrated that REGEN-COV shortened symptom duration and markedly reduced viral levels.
The trial enrolled 204 individuals without any COVID-19 symptoms who tested positive for SARS-CoV-2 but did not have anti-virus antibodies at baseline and were randomized to receive either one dose of REGEN-COV (1,200 mg) or placebo.
“COVID-19 transmission often occurs via infected people who do not yet have symptoms, so it is critical that we rapidly diagnose and treat these individuals for their own health and to prevent transmission,” said Katharine Bar, M.D., co-principal investigator of the trial and Assistant Professor of Medicine, Infectious Diseases, Hospital of the University of Pennsylvania. “These data pave the way for REGEN-COV to be used before patients become symptomatic, with a more convenient subcutaneous administration.”
The trial met all primary and key secondary endpoints. In addition to reducing the risk of symptomatic infections, the total number of weeks patients experienced symptoms was nearly cut in half (45%) with REGEN-COV, and the viral burden was reduced by more than 90%. While not included in the initial analysis plan, researchers also found that no REGEN-COV patients and six placebo patients were either hospitalized or visited the emergency room because of COVID-19 during the 29-day efficacy assessment period.
“These Phase 3 data provide even more evidence that REGEN-COV, this time given to asymptomatic patients via convenient injections, can change the course of COVID-19 infection in non-hospitalized patients,” said George D. Yancopoulos, M.D., Ph.D., President and Chief Scientific Officer at Regeneron. “In this trial, the REGEN-COV antibody cocktail effectively prevented asymptomatic patients from becoming symptomatic, and rapidly lowered their viral load.”
REGEN-COV continues to be evaluated in clinical trials in multiple settings for COVID-19: for the prevention of COVID-19 in household contacts of infected individuals, and in non-hospitalized and certain hospitalized patients, including the open-label RECOVERY trial of hospitalized patients in the UK. As of April 2021, more than 25,000 people have participated in clinical trials involving REGEN-COV.
The development and manufacturing of REGEN-COV have been funded in part with federal funds from the Biomedical Advanced Research and Development Authority (BARDA), part of the U.S. Department of Health and Human Services, Office of the Assistant Secretary for Preparedness and Response.
Among participants enrolled in the treatment trial, 35% were Latino/Hispanic and 5% were Black/African American. In total, 32% had at least one known factor that put them at high risk of suffering severe consequences from COVID-19.
REGEN-COV is currently available in the U.S. to treat mild-to-moderate COVID-19 in adults, as well as in pediatric patients at least 12 years of age and weighing at least 40 pounds, who have received positive results of direct SARS-CoV-2 viral testing and are at high risk for progressing to severe COVID-19 and/or hospitalization. REGEN-COV has not been approved by the FDA but has been authorized for emergency use.