Regeneron’s Antibody Cocktail for COVID-19 Enters Phase III Testing

Regeneron’s Antibody Cocktail for COVID-19 Enters Phase III Testing

Regeneron’s investigational dual-antibody cocktail drug contains two antibodies that bind non-competitively to critical portions of the outer spike protein of the SARS-CoV-2 virus. This would prevent the virus from infecting host cells to cause infection.

Regeneron announced on Monday that its experimental double antibody cocktail, which is touted to both treat and prevent COVID-19 infection, will soon enter late-stage clinical testing.

The biotechnology giant’s antiviral antibody cocktail drug, called REGN-COV2, has also moved to the Phase II/III portion of two adaptive Phase I/II/III treatment trials following positive Phase I safety review, according to a press release from the company. The Phase I safety trials involved an initial cohort of 30 hospitalized and non-hospitalized (i.e. ‘ambulatory’) COVID-19 patients, the results of which received a positive review from the Independent Data Monitoring Committee.

The Phase III COVID-19 prevention trial for the treatment will be conducted in collaboration with the National Institute of Allergy and Infectious Diseases (NIAID).

“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, 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 antiviral antibody cocktail that could be available much sooner than a vaccine.”

One day after the announcement, Regeneron revealed that it was awarded a $450 million contract to manufacture and supply the antibody treatment as part of the US federal government’s “Operation Warp Speed” COVID-19 vaccine program.

Related: Eli Lilly and AbCellera Begin Phase I Trials for a COVID-19 Antibody Treatment

The Phase III prevention trial will assess the drug’s ability to prevent COVID-19 infection among uninfected people who have had close contact with an infected person. The multi-center trial will take place at 100 different sites across the US and is expected to include approximately 2,000 participants.

The two Phase II/III adaptive treatment trials will include an estimated 1,850 hospitalized and 1,050 non-hospitalized patients at approximately 150 sites in the US, Brazil, Mexico and Chile. The studies will evaluate virologic and clinical endpoints, with preliminary data expected later this summer. As the trials are adaptively-designed, the eventual numbers of patients enrolled will depend on how the trial progresses and results from the Phase II studies.

REGN-COV2 is a dual-antibody cocktail that contains two of the most potent, non-competing and virus-neutralizing antibodies developed by scientists at Regeneron. The two lead antibody candidates were selected from 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, according to Regeneron.

The dual-antibody cocktail was scaled up using the company’s manufacturing capabilities and VelociMab technologies, which “enable the high-throughput screening of potential therapeutic antibodies and the rapid generation of cell lines for recombinant human antibodies, allowing researchers to go from mouse immunization to production cell line bioreactor harvest within eight months.”

The two antibodies of REGN-COV2 bind non-competitively to critical portions of the receptor binding domain of the virus’ spike protein, helping ensure that any mutant strains of the virus do not evade treatment. The treatment could also help prevent coronavirus infection by blocking the ability of the spike protein to bind to target host cells and facilitate viral entry.

Antibody drugs are becoming increasingly attractive therapeutics for the SARS-Cov-2 virus as they can be designed to specifically target viral antigens. In addition to Regeneron, Eli Lilly and AbCellera also began testing their antibody treatment in humans as of June 1, and there are a number of other companies working