Regeneron says antibody therapy loses potency against omicron

Regeneron Pharmaceuticals Inc. said on Thursday that an antibody therapy frequently used in unvaccinated COVID-19 patients has “diminished” potency against the omicron variant. 

“While Regeneron’s currently authorized REGEN-COV antibodies have diminished potency against Omicron, they are active against Delta, which currently is the most prevalent variant in the U.S.,” Regeneron said in an announcement.

The biotechnology company, however, said that its monoclonal antibodies were still active in patients who had either the omicron or delta variant.

“Regeneron has confirmed that multiple ‘next generation’ monoclonal antibodies from its large collection of fully human monoclonal antibodies targeting SARS-CoV-2 are active against the Omicron (B.1.1.529) and Delta (B.1.617.2) variants, as well as against the other variants of concern,” Regeneron said. “Pending regulatory discussions, we anticipate entering the clinic in the first quarter of 2022.”

Regeneron had signaled in late November that its antibody treatment “may be” less effective at targeting the new omicron variant, saying in a statement at the time that previous analyses “indicate that there may be reduced neutralization activity of both vaccine-induced and monoclonal antibody-conveyed immunity, including the current REGEN-COV antibodies.”

Regeneron noted at the time that tests were still ongoing.

The monoclonal bodies, which have received emergency use authorization from the Food and Drug Administration, are not a substitute for the COVID-19 vaccine. 

Researchers from Israel as well as Pfizer and BioNTech have said that the booster appears to shore up protection against the omicron variant. President Biden’s chief medical adviser, Anthony Fauci, concurred on Wednesday, saying that “our booster vaccine regimens work against omicron.”

“At this point there is no need for a variant-specific booster,” he said during a press briefing. 

The Hill reported Wednesday on a preprint study that indicated that the antibodies in blood samples from recipients of two Moderna doses were less effective at neutralizing the omicron variant, suggesting an increased risk of symptomatic breakthrough cases.