Regeneron Halts Enrollment of Severe Patients in COVID-19 Antibody Trial Following Possible Safety Signal

Despite announcing positive results for its phase 2/3 COVID-19 antibody cocktail trial Thursday, a potential safety signal has led Regeneron to temporarily stop enrolling patients who require high-flow oxygen or mechanical ventilation.

The company revealed Friday that it is following the recommendations of the independent data monitoring committee (IDMC) in the U.S. looking over its antibody cocktail trials to halt enrollment of hospitalized participants with high oxygen requirements.

“Based on a potential safety signal and an unfavorable risk/benefit profile at this time, the IDMC recommends further enrollment of patients requiring high-flow oxygen or mechanical ventilation be placed on hold pending collection and analysis of further data on patients already enrolled,” Regeneron said Friday.

The enrollment freeze comes just a day after Regeneron announced results showing its antibody cocktail, REGN-COV2, significantly lessened viral load and the number of medical site visits needed by nonhospitalized patients in its phase 2/3 trial (DID, Oct. 30).

Despite the setback, the IDMC advised Regeneron researchers to continue enrolling hospitalized patients who either don’t need oxygen or only require it at low-flow rates and recommended that Regeneron continue its outpatient trial without any changes.

The company said it has informed both the FDA and the IDMC for the UK’s RECOVERY trial, which is evaluating the antibody cocktail, about the IDMC’s recommendations in the U.S. The company did not elaborate on the details of the potential safety signal.

The FDA is currently reviewing Regeneron’s Emergency Use Authorization submission for its antibody cocktail as a COVID-19 treatment for high-risk, mild-to-moderate nonhospitalized COVID patients. — James Miessler