Single-Dose Monoclonal Antibody Cocktail Produces Long-Term Protection

New York-based Regeneron Pharmaceuticals, Inc. today announced additional positive results from a Phase 3 trial jointly run with the National Institute of Allergy and Infectious Diseases, which assessed the use of a single dose of investigational REGEN-COV®  to prevent COVID-19 in uninfected individuals.

The new analyses show REGEN-COV (1,200 mg administered via four subcutaneous injections) reduced the risk of contracting COVID-19 by 81.6% during the pre-specified follow-up period (months 2-8).

During the 8-month assessment period, there were (0) hospitalizations for COVID-19 in the REGEN-COV group and (6) in the placebo group.

And REGEN-COV maintained the 81.4% risk reduction during the first month after administration, as previously reported in The NEJM during September 2021.

"Today's new data demonstrate how a single dose of REGEN-COV can help protect people from COVID-19 for many months after administration," said Myron S. Cohen, M.D., who leads the monoclonal antibody efforts for the NIH-sponsored COVID Prevention Network and is Director of the Institute for Global Health & Infectious Diseases at the University of North Carolina at Chapel Hill.

"These results demonstrate that REGEN-COV has the potential to provide long-lasting immunity from SARS-CoV-2 infection."

This finding "is particularly important to those who do not respond to COVID-19 vaccines, including people who are immunocompromised," commented Dr. Cohen in a press release.

REGEN-COV (casirivimab and imdevimab) is a cocktail of two monoclonal antibodies explicitly designed to block the infectivity of SARS-CoV-2, the betacorinavirus 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 the journal Cell.

REGEN-COV has not been approved by the U.S. FDA but is currently authorized for the treatment and post-exposure prophylaxis in certain high-risk individuals.

On November 8, 2021, Mary Talley Bowden, M.D., board-certified in both Otolaryngology and Sleep Medicine, spoke with Precision Vaccinations, "I have treated 1,346 patients with REGEN-COV since August 2021. Our rate of subsequent hospitalization was 0.3%."

"Furthermore, we have seen no serious or unusual side effects from treatment."

"About 97% of our patients would recommend this treatment to a loved one," added Dr. Bowden, who is with BreatheMD, located in Houston, TX.

In October 2021, the FDA accepted for priority review the first of two Biologics License Applications (BLAs) for REGEN-COV to treat COVID-19 in non-hospitalized patients and as prophylaxis in specific individuals.

The second BLA submission will focus on those hospitalized because of COVID-19 and is expected to be completed in late 2021.

Regeneron is collaborating with Roche to increase the global supply of the antibody cocktail, with Roche primarily responsible for development and distribution outside the U.S.