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Regeneron Monoclonal Antibodies Neutralize Against UK and South African Variants

Independent investigators assessed in vitro neutralization potency using the antibody therapy, Regen-Cov, against the B.1.1.7 and B.1.351 strains.

Regeneron announced today its antibody therapy, Regen-Cov,(casirivimab and imdevimab), neutralizes the B.1.1.7 (UK variant) and B.1.351 (South Africa variant).

"As we expected, the virus continues to mutate, and these data show the continued ability of REGEN-COV to neutralize emerging strains, further validating our multi-antibody cocktail approach to infectious diseases," George Yancopoulos, MD, PhD, president and CSO, Regeneron, said. "With two complimentary antibodies in one therapeutic, even if one has reduced potency, the risk of the cocktail losing efficacy is significantly diminished, since the virus would need to mutate in multiple distinct locations to evade both antibodies."

The findings were confirmed independently by investigators at Columbia University and the company. The university published its findings on bioRxiv.

Both teams of researchers assessed in vitro neutralization potency of numerous COVID-19 antibodies—including those that have received emergency authorization and those still in development—against various mutated strains of the virus. Although some antibody therapies were no longer effective against some of these variants, the Regen-Cov antibody cocktail continued to neutralize all variants tested.

The company did not test against the latest variant first seen in Brazil (B.1.1.248). However, this variant contains the same receptor binding domain mutations as the B.1.351 variant, and Regeneron believes Regen-Cov will remain similarly potent. Regeneron is conducting additional preclinical research against this particular strain to confirm this.

Regen-Cov is a cocktail of two monoclonal antibodies (also known as REGN10933 and REGN10987) and was designed specifically to block infectivity of SARS-CoV-2, the virus that causes COVID-19.

In late the November, The US Food and Drug Administration (FDA) issued an Emergency Use Authorization (EUA) for Regen-Cov, for the combined treatment of mild to moderate coronavirus 2019 (COVID-19).

The EUA allowed for the intravenous (IV) therapy to be used on adults and pediatric patientswith positive SARS-CoV-2 viral testing results deemed to be at high risk for progression to severe COVID-19.This patient population included those ≥65 years old or those who have chronic medical conditions.