Regeneron Launches Phase 3 Trial of Double Antibody Cocktail for Treatment and Prevention of COVID-19

Regeneron Pharmaceuticals, Inc. (Tarrytown, NY, USA) has initiated late-stage clinical trials evaluating REGN-COV2, the company’s investigational double antibody cocktail for the treatment and prevention of COVID-19.

Regeneron scientists have evaluated thousands of fully-human antibodies produced by the company's proprietary VelocImmune mice, which have been genetically-modified to have a human immune system, as well as antibodies isolated from humans who have recovered from COVID-19. It has selected the two most potent, non-competing and virus-neutralizing antibodies to create REGN-COV2 and scaled up this dual-antibody cocktail for clinical use with the company's in-house VelociMab and manufacturing capabilities. REGN-COV2's two antibodies 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.

A Phase 3 trial will evaluate REGN-COV2's ability to prevent infection among uninfected people who have had close exposure to a COVID-19 patient (such as the patient's housemate), and is being run jointly with the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH). REGN-COV2 has also moved into the Phase 2/3 portion of two adaptive Phase 1/2/3 trials testing the cocktail's ability to treat hospitalized and non-hospitalized (or "ambulatory") patients with COVID-19. This clinical progress follows a positive review from the Independent Data Monitoring Committee of REGN-COV2 Phase 1 safety results in an initial cohort of 30 hospitalized and non-hospitalized patients with COVID-19.

The Phase 3 prevention trial is being conducted at approximately 100 sites and is expected to enroll 2,000 patients in the US; the trial will assess SARS-CoV-2 infection status. The company plans to conduct two Phase 2/3 treatment trials in hospitalized (estimated enrollment 1,850) and non-hospitalized (estimated enrollment 1,050) patients at approximately 150 sites in the US, Brazil, Mexico and Chile, and evaluate virologic and clinical endpoints, with preliminary data expected later this summer. All trials are adaptively-designed, and the ultimate numbers of patients enrolled will depend on trial progress and insights from Phase 2 studies.

"We are running simultaneous adaptive trials in order to move as quickly as possible to provide a potential solution to prevent and treat COVID-19 infections, even in the midst of an ongoing global pandemic," said George D. Yancopoulos, M.D., Ph.D., Co-Founder, President and Chief Scientific Officer of Regeneron. "We are pleased to collaborate with NIAID to study REGN-COV2 in our quest to further prevent the spread of the virus with an anti-viral antibody cocktail that could be available much sooner than a vaccine."

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