Regeneron’s COVID-19 Antibody Cocktail Helps Hospitalized Patients

Regeneron recently announced that its COVID-19 antibody cocktail, REGEN-COV, significantly reduced viral load in patients hospitalized with the coronavirus.

The trial enrolled 1,197 patients to randomly receive REGEN-COV 8,000 milligrams, REGEN-COV 2,400 milligrams, or placebo. 

Patients who received the antibody combination experienced a 36 percent reduced risk of dying within 29 days of receiving treatment. And patients who were seronegative when entering the trial experienced a 56 percent reduced risk. 

In a separate analysis of 2,007 patients, serious adverse events occurred in 21 percent of the REGEN-COV group and 26 percent in the placebo group. 

Notably, researchers did not observe any difference between the two REGEN-COV doses or any serious safety signals overall. 

The Phase 2/3 trial initially assessed a broad group of patients. But in 2020, researchers adjusted the trial to exclude patients on mechanical ventilation at baseline due to a potential safety signal.

The recent trial results were also similar to the larger UK RECOVERY trial in hospitalized patients, with improvements across all clinical endpoints assessed.

“These new results, combined with the nearly 10,000-patient RECOVERY trial, further validate how REGEN-COV can change the course of illness for patients even after they are hospitalized with COVID-19,” George D. Yancopoulos, MD, PhD, president and chief scientific officer at Regeneron, said in the announcement. 

Yancopoulos also emphasized that while this trial and the RECOVERY trial show that patients unable to develop their own antibodies against the virus gained the most significant benefit from treatment with REGEN-COV, both were conducted before widespread vaccination and before the emergence of variants. 

But multiple analyses have shown that REGEN-COV retains potency against the main variants of concern, including Delta, Gamma, Beta, and Mu. 

FDA issued an emergency use authorization to REGEN-COV in November 2020. 

Then in August 2021, FDA updated the authorization to include post-exposure prophylaxis in individuals at high risk of severe disease who are not fully vaccinated, may not mount an adequate response to vaccination, and have been exposed to COVID-19 or are at high risk of exposure.