The US Food and Drug Administration (FDA) has updated the Emergency Use Authorization (EUA) for Regeneron Pharmaceuticals’ Covid-19 antibody cocktail, REGEN-COV, reducing the dose to 1,200mg from 2,400mg.

A combination of two monoclonal antibodies, casirivimab and imdevimab, REGEN-COV was designed utilising Regeneron’s VelocImmune and VelociSuite technologies to potentially hinder SARS-CoV-2 infectivity.

Earlier, 2,400mg (1,200mg casirivimab plus 1,200mg imdevimab) intravenous (IV) dose of REGEN-COV was authorised by the FDA.

REGEN-COV is indicated for treating mild-to-moderate Covid-19 in adults and paediatric patients aged 12 years or above, who are at an increased risk for disease progression, including hospitalisation or death.

The updated EUA says REGEN-COV should be given as IV doses and subcutaneous (SC) doses can be used when IV infusion is not practicable and could delay the treatment.

Regeneron Pharmaceuticals president and chief scientific officer George Yancopoulos said: “Despite the increased use of vaccines, thousands of patients are still becoming infected in the US every day, with many at high risk of serious complications from Covid-19.

“REGEN-COV has also demonstrated potency against the main variants of concern to date in vitro and is the only antibody therapy currently available across the US, including in states where variants first identified in Brazil and South Africa are circulating at a higher rate.”

The latest FDA update is based on data from various trials, which includes results from a Phase III trial that demonstrated that REGEN-COV lowered the risk of hospitalisation or death by 70% in high-risk non-hospitalised subjects.

Furthermore, data showed that the treatment effect with 1,200mg and 2,400mg doses of the antibody cocktail was similar.

Based on the total scientific evidence available, including clinical, viral load reduction and pharmacokinetic data, FDA authorised the SC administration of REGEN-COV.

Regeneron intends to apply for a full Biologics License Application (BLA) for the antibody cocktail in non-hospitalised Covid-19 patients later this year.

In addition, the US Government has agreed to buy all REGEN-COV doses delivered by 30 June and could receive further doses till 30 September, up to a total of 1.25 million doses, the company noted.

In August last year, Roche partnered with Regeneron to develop, manufacture and distribute REGN-COV2 for Covid-19.