Phase 3 Trial Shows REGEN-COV antibody Cocktail Reduced Hospitalization or Death by 70% in Non-hospitalized COVID-19 Patients

Regeneron Pharmaceuticals, Inc. announced positive topline results from the largest trial to date assessing a COVID-19 treatment in infected non-hospitalized patients (n=4,567). This definitive Phase 3 outcomes trial in high-risk non-hospitalized COVID-19 patients (“outpatients”) met its primary endpoint, showing the investigational REGEN-COV™ (casirivimab with imdevimab) significantly reduced the risk of hospitalization or death by 70% (1,200 mg intravenous [IV]) and 71% (2,400 mg IV) compared to placebo.

“This is a landmark moment in the fight against COVID-19 as this large well-controlled trial provides conclusive results demonstrating that REGEN-COV can dramatically reduce the risk of hospitalization and death in the outpatient setting,” said Suraj Saggar, D.O., trial investigator and Chief of Infectious Disease at Holy Name Medical Center in Teaneck, New Jersey. “With so many people still getting infected, as well as recent data showing that REGEN-COV addresses emerging variants, these data underscore the need to rapidly adopt REGEN-COV as standard-of-care to offer high-risk patients their best chance to reduce serious consequences like hospitalization or death.”

REGEN-COV also met all secondary endpoints in the Phase 3 outcomes trial, including the ability to reduce symptom duration. In addition, a companion Phase 2 trial showed that even the lowest doses tested (IV: 300 mg; subcutaneous [SC]: 600 mg) had significant viral load reductions over the first 7 study days, comparable to the 2,400 mg and 1,200 mg IV doses.

“With approximately 60,000 newly diagnosed individuals in the U.S. every day and 40,000 still in the hospital because of COVID-19, we are committed to working with the government, healthcare providers and others to support rapid and widespread adoption of REGEN-COV in appropriate patients,” said George D. Yancopoulos, M.D., Ph.D., President and Chief Scientific Officer at Regeneron. “We will discuss the new data with regulatory authorities and request that the 1,200 mg dose be rapidly added to the U.S. Emergency Use Authorization, in order for the anticipated REGEN-COV supply to be available to treat even more patients. These Phase 3 data will also form the basis of a full Biologics License Application.”

A safety assessment was conducted on all available patient data up to day 169, and identified no new safety signals. Serious adverse events (SAEs) were largely related to COVID-19 and occurred in 1.1% of patients in the 1,200 mg group, 1.3% in the 2,400 mg group and 4.0% in the placebo group. There was 1 death in the 1,200 mg group (n=827), 1 death in the 2,400 mg group (n=1,849) and 5 deaths in the placebo groups (n=1,843).

All patients in this analysis had at least one risk factor, including obesity (58%), age ³50 years (51%) and cardiovascular disease, including hypertension (36%). Approximately 35% of patients were Latino/Hispanic, 5% were Black/African American and the median age was 50 years (range: 18-96 years).

About the REGEN-COV Antibody Cocktail
REGEN-COV (casirivimab with imdevimab) is a cocktail of two monoclonal antibodies (also known as REGN10933 and REGN10987) that was designed specifically to block infectivity of SARS-CoV-2, the virus that causes COVID-19, using Regeneron’s proprietary VelocImmune® and VelociSuite® technologies. The two potent, virus-neutralizing antibodies that form the cocktail bind non-competitively to the critical receptor binding domain of the virus’s spike protein, which diminishes the ability of mutant viruses to escape treatment and protects against spike variants that have arisen in the human population, as detailed in Science.