Regeneron Pharmaceuticals is set to put a hold on enrolling patients requiring high-flow oxygen or mechanical ventilation in the trial of REGN-COV2, an antibody cocktail therapy for treating hospitalised patients with Covid-19.

The move follows an independent data monitoring committee (IDMC) recommendation that is based on a potential safety signal and an unfavourable risk/benefit profile at this time.

REGN-COV2 is a combination of two monoclonal antibodies REGN10933 and REGN10987. It can potentially block infectivity of SARS-CoV-2, the virus that causes Covid-19.

As recommended by the IDMC, Regeneron will continue to enrol hospitalised patients requiring either no or low-flow oxygen and the outpatient trial without modification.

The US Food and Drug Administration is currently evaluating REGN-COV2 for a potential emergency use authorisation (EUA) in mild-to-moderate outpatients at high risk for poor outcomes. Regeneron will also inform FDA of the latest development.

The IDMC recommendation will also be shared with the independent committee, which is monitoring the RECOVERY trial evaluating REGN-COV2 in hospitalised patients in the UK.

Regeneron noted that the REGN-COV2 trial in hospitalised patients has been designed to enrol patients in four cohorts that are independently randomised.

Cohort 1 involves patients on low-flow oxygen and cohort 1A will include patients who do not require oxygen.

Patients on high-flow oxygen and those on mechanical ventilation will be part of cohort 2 and cohort 3, respectively.

Last month, Regeneron reported positive results from an ongoing Phase II/III seamless trial of REGN-COV2 in the Covid-19 outpatient setting.

Data from the trial showed that REGN-COV2 significantly reduced viral load and patient medical visits, including hospitalisations, emergency room, urgent care visits and/or physician office/telemedicine visits.