Regeneron’s Covid mAb as a prophylactic injection: Reduced risk of symptomatic infection by 81%
Regeneron’s monoclonal antibody cocktail for Covid-19 continues to impress, this time in a joint trial with NIH that found the normally infused treatment works as a preventive subcutaneous injection.
The trial showed that REGEN-COV (casirivimab with imdevimab) reduced the risk of symptomatic infections by 81% in those who did not have Covid before the trial within 29 days. There were 11 cases in the 753-person mAb arm, versus 59 cases in the 752-person placebo arm.
Part of the reason the uptake of monoclonal antibodies like Regeneron’s has been slow is because they require time-consuming infusions in specialized centers. Each of the leading mAb developers have been seeking to speed the infusion process or figure out ways to administer a mAb therapy as an injection.
“I think the switch to subcutaneous administration is significant because it has the potential to move use away from infusion centers and to doctor’s offices or even in home administration. This would likely have the effect of increasing use,” Jeff Henderson, an infectious disease doctor at Washington University in St. Louis and who was not involved with the trial, told Endpoints News.
The trial results have not been published yet in a peer-reviewed journal, but Regeneron said it will share the data with the US FDA and request that the EUA be expanded to include preventive treatment for the appropriate populations, using a 1,200 mg subcutaneous dose.
“If authorized, convenient subcutaneous administration of REGEN-COV could help control outbreaks in high-risk settings where individuals have not yet been vaccinated, including individual households and group living settings,” Myron Cohen, who leads the monoclonal antibody efforts for the NIH-sponsored COVID Prevention Network, said in a statement.
On average, individuals treated with REGEN-COV in this latest trial and who experienced a symptomatic infection resolved their symptoms in about 1 week, compared to about 3 weeks for those on placebo. “REGEN-COV had rapid onset, with 72% protection against symptomatic infections in the first week, rising to 93% in subsequent weeks,” the company said.
The mAb cocktail is currently available under an emergency use authorization for those 12 and older who aren’t hospitalized and have mild-to-moderate Covid-19 and are at high risk for progressing to severe Covid-19 and/or hospitalization. The US government has spent more than $3 billion to help develop, manufacture and purchase about 1.5 million treatment courses of Regeneron’s therapeutic, which are expected to be delivered in the first half of this year.
Henderson also said that looking at all of the data on monoclonal antibody treatments for Covid-19, this result makes sense because the sooner they can be administered, generally, the better the outcome. “This is what would be expected, but it’s very good,” he said.