IDMC recommends modifications to Regeneron COVID-19 antibody trial

The Independent Data Monitoring Committee (IDMC) has recommended that Regeneron Pharmaceuticals modify its clinical trial to test its REGN-COV2 antibody cocktail treatment in hospitalised COVID-19 patients. 

Based on a potential safety signal and an unfavourable risk/benefit profile at this time, 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 on patients already enrolled.

The committee has also recommended the continuation of enrolment for hospitalised COVID-19 patients requiring either no or low-flow oxygen as the risk/benefit remains acceptable in these cohorts. Finally, the IDMC recommends continuation of the outpatient trial without modification.

The REGN-COV2 trial in hospitalised patients is designed to enrol patients in four independently randomised cohorts: 

• Cohort 1: patients on low-flow oxygen
• Cohort 1A: patients not requiring oxygen
• Cohort 2: patients on high-flow oxygen
• Cohort 3: patients on mechanical ventilation.

Regeneron has said it remains blinded to the data and is implementing the IDMC recommendations. The company is also informing the US Food and Drug Administration (FDA), which is currently evaluating REGN-COV2 for a potential Emergency Use Authorization (EUA) in mild-to-moderate outpatients at high risk for poor outcomes. Regeneron is also sharing the recommendation with the independent committee monitoring the RECOVERY trial in the UK, which is evaluating REGN-COV2 in hospitalised patients.

REGN-COV2 (REGN10933 and REGN10987) is a combination of two monoclonal antibodies (mAbs) and was designed specifically to block infectivity of SARS-CoV-2, the virus that causes COVID-19. The two potent, virus-neutralising antibodies that form REGN-COV2 bind non-competitively to the critical receptor binding domain of COVID-19’s Spike (S) protein, which diminishes the ability of mutant viruses to escape treatment and protects against S variants that have arisen in the human population, as detailed in Science.

Regeneron says that if REGN-COV2 proves safe and effective in clinical trials and regulatory approvals are granted, the company will manufacture and distribute it in the US and Roche will develop, manufacture and distribute it outside the U.S.