Regeneron’s antibody cocktail hits target in COVID prevention study

Regeneron is to ask the FDA for clearance to use its antibody cocktail as a preventive treatment for COVID-19.

The therapy is already authorised by the FDA for adults with mild-to-moderate disease and paediatric patients at least 12 years of age who have tested positive for the virus and are at high risk of serious disease.

The US pharma said results of the latest phase 3 trial showed that REGEN-COV (casirivimab+imdevimab) significantly reduced progression to symptomatic COVID-19 disease in uninfected individuals.

Regeneron reported findings from the trial, which involved a patient-friendly subcutaneous formulation of the therapy, which was famously given to president Donald Trump after he became infected with the disease late last year.

The prevention trial, which was jointly run with the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH), met its primary and key secondary endpoints.

It showed that REGEN-COV 1,200 mg administered subcutaneously (SC) reduced the risk of symptomatic infections by 81% in those who were not infected when they entered the trial.

The trial  assessed the effect of REGEN-COV on uninfected individuals without anti-SARS-CoV-2 antibodies or any COVID-19 symptoms, who lived in the same household as an individual who tested positive for SARS-CoV-2 within the prior four days. The trial enrolled 1,505 people who were not infected with SARS-CoV-2 at baseline and randomly received either one dose of REGEN-COV (1,200 mg) or placebo, administered as SC injections.

Myron Cohen,who leads the monoclonal antibody efforts for the NIH-sponsored COVID Prevention Network (CoVPN) and is director of the Institute for Global Health & Infectious Diseases at the University of North Carolina at Chapel Hill, said: “Despite standard precautions to reduce transmission, nearly 10% of unvaccinated individuals living with an infected person developed symptomatic infections if they did not receive REGEN-COV.

“If authorised, convenient subcutaneous administration of REGEN-COV could help control outbreaks in high-risk settings where individuals have not yet been vaccinated, including individual households and group living settings.”

Data from a separate phase 3 2069B trial of recently infected asymptomatic COVID-19 patients, showed REGEN-COV reduced risk of progression to symptomatic disease in recently infected people without symptoms.

The placebo-controlled trial also involved the subcutaneous formulation and showed the treatment cut chances of progression by 76% after the third day and shortened symptom duration and markedly reduced viral levels.

The trial enrolled 204 individuals without any COVID-19 symptoms who tested positive for SARS-CoV-2 but did not have anti-virus antibodies at baseline, and randomly received either one dose of REGEN-COV (1,200 mg) or placebo.

The trial met all primary and key secondary endpoints. In addition to reducing the risk of symptomatic infections, the total number of weeks patients experienced symptoms was nearly cut in half (45%) with REGEN-COV, and the viral burden was reduced by more than 90%.

While not included in the initial analysis plan, researchers also found that no REGEN-COV patients and six placebo patients were either hospitalised or visited the emergency room because of COVID-19 during the 29-day efficacy assessment period.

REGEN-COV is one of several antibody therapies developed to treat COVID-19: Eli Lilly already has a rival approved by the FDA under emergency measures, while AstraZeneca is one of several pharmas developing rivals.

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