Regeneron says study shows its monoclonal antibody cocktail works against coronavirus variants

The tests also confirm what other teams of researchers have found: vaccines are likely to protect people against both the variant first seen in Britain and known as B.1.1.7, and one first noted in South Africa and called B.1.135. However, the mutations in B.1.135 do allow the virus to evade immune responses a little more, the team, led by Dr. David Ho at Columbia University's Aaron Diamond AIDS Research Center, reported in a pre-print report -- one not yet published in a peer-reviewed journal.

Regeneron's cocktail has been granted emergency use authorization by the US Food and Drug Administration, and it was used to treat former president Donald Trump when he was infected with coronavirus last year.

"As we expected, the virus continues to mutate, and these data show the continued ability of REGEN-COV to neutralize emerging strains, further validating our multi-antibody cocktail approach to infectious diseases," Regeneron president Dr. George Yancopoulos said in a statement.

"With two complementary antibodies in one therapeutic, even if one has reduced potency, the risk of the cocktail losing efficacy is significantly diminished, since the virus would need to mutate in multiple distinct locations to evade both antibodies."

Ho's team tested convalescent plasma from 20 patients who recovered from Covid-19, and also blood from 22 people who got two doses of either Pfizer's or Moderna's coronavirus vaccines. They also tested Eli Lilly and Company's single monoclonal antibody treatment, which also has an EUA.

The mutations in B.1.1.7 had small effects, if any. But one mutation especially, in B.1.135, did reduce the efficacy of the immune response in convalescent plasma, in both vaccines, of one of Regeneron's antibodies and of Lilly's antibody, they said.

The same mutation is found in a variant first seen in Brazil.

"Mutationally, this virus is traveling in a direction that could ultimately lead to escape from our current therapeutic and prophylactic interventions directed to the viral spike," Ho's team wrote.

"If the rampant spread of the virus continues and more critical mutations accumulate, then we may be condemned to chasing after the evolving SARS-CoV-2 continually, as we have long done for influenza virus."

This means the world must vaccinate people faster and, in the meantime, double down on measures to stop the spread of virus, such as mask use, they said.