Regeneron's COVID-19 antibody cocktail therapy hits safety problem

Regeneron’s coronavirus antibody cocktail therapy against COVID-19, famously used to treat president Donald Trump, has hit a safety issue after independent safety experts recommended it should not be given to high-risk patients in a late-stage clinical trial.

It’s the latest blow for antibody therapies against COVID-19 after Eli Lilly last week announced it won’t resume a trial in hospitalised patients, after National Institutes of Health researchers concluded it wouldn’t help.

Regeneron said an Independent Data Monitoring Committee (IDMC) from the REGN-COV2 trial said that based on an unspecified safety signal and an “unfavourable risk benefit profile” the committee recommends a modification to the trial protocol.

The IDMC recommends further enrolment of patients requiring high-flow oxygen or mechanical ventilation be placed on hold pending collection and analysis of further data from those already on the trial.

Regeneron remains blinded to the data and is implementing the recommendations.

The company has also informed the FDA, which is reviewing REGN-COV2 data for a potential Emergency Use Authorization in patients with mild-to-moderate outpatients at high risk for poor outcomes.

The data is also being shared with the independent committee monitoring the RECOVERY trial in the UK, which is testing the drug cocktail in hospitalised patients.

REGN-COV2 is split into four cohorts – patients on low-flow oxygen, patients not requiring oxygen, patients on high-flow oxygen and patients on mechanical ventilation.

The spotlight has been on antibody therapies for COVID-19 after it emerged early last month that Trump was treated with the Regeneron combination.

Regeneron’s therapy is based on two antibodies the company has developed to neutralise the virus.

The rationale is that by having a double therapy, the chances of the virus developing resistance to both parts of the drug are reduced.

AstraZeneca is to begin phase 3 trials of a long-acting antibody therapy combination in the US and other countries in the coming weeks, to prevent infection happening and as therapy for those already infected.