Most antibody drugs ineffective against Brazil coronavirus variant

The coronavirus variant first identified in Brazil, known as P.1, is resistant to three of the four antibody therapies with emergency use authorization in the United States, according to a laboratory study.

In test-tube experiments, researchers exposed the P.1 variant to various monoclonal antibodies, including the four currently being used to treat U.S. COVID-19 patients – imdevimab and casirivimab from Regneron Pharmaceuticals, and bamlanivimab and etesevimab from Eli Lilly and Co.

Only imdevimab retained any potency, researchers found. The neutralizing ability of the other three were “markedly or completely abolished,” according to a peer reviewed report available on bioRxiv and provisionally accepted by the journal Cell Host & Microbe.

The researchers also exposed P.1 to plasma from COVID-19 survivors and blood from recipients of vaccines from Pfizer/BioNTech or Moderna. Compared to their effects against the original version of the coronavirus, the plasma and the vaccine-induced antibodies were less effective at neutralizing P.1.

In earlier studies, however, they were even less effective against the B.1.351 variant first identified in South Africa.

This suggests that the Brazil variant might not pose as great a threat of reinfection or decreased vaccine protection as the South Africa variant, said coauthor David Ho from Columbia University. Real-world evidence is needed to confirm the lab results, he said