BA.4.6 is a derivative of the BA.4 subvariant of the Omicron coronavirus variant. Only a few mutations distinguish it from its predecessor, but in the US it is slowly gaining ground even against BA.5, which continues to dominate infections.
Evusheld is a lab-created, long-lasting combination of two antibodies manufactured by AstraZeneca. Semi-annual dosing can prevent Covid-19 infection in people who may not receive adequate protection from vaccines because their immune systems are unable to respond effectively. We estimate that we may benefit from Evusheld’s protection.
This important treatment has held up well against new coronavirus variants. But in a new test, Dr. David Ho, professor of microbiology and immunology at Columbia University, found that while this subvariant does not appear to bind cells more readily than other subvariants, some Evusheld’s, including those of Evusheld, appear to circumvent the ability of antibodies to neutralize.
“We found that combination antibody no longer worked against this new variant, the only antibody combination approved for the prevention of Covid-19,” Ho told CNN.
Ho and his team have worked throughout the pandemic to rapidly characterize new variants to help the US improve its therapeutic strategies.
Ho said he also sent his results to the National Institutes of Health and the U.S. Food and Drug Administration.
In a statement, the FDA said, “We are working with the sponsors of all currently approved therapeutics to evaluate their activity against the global SARS-CoV-2 variants of interest and will inform the public as soon as we have more information. We are working to communicate with people from all over the world.”
AstraZeneca said Evusheld’s antibodies work together and testing them separately may not reflect how the actual treatment works.
“There is limited relevance between studies evaluating Evusheld component antibodies individually and in combination, or studies attempting to replicate versions of tixagevimab and cilgavimab and authentic Evusheld. Data for individual Evusheld antibodies are , does not represent a synergistic effect of the combination.The antibody recreated in the laboratory based on publicly available information is not an exact replica of Evusheld,” the spokesperson said in a statement.
In the meantime, those with compromised immune systems should know that Evusheld may not be as protective as it used to be, says Ho.
“Note that BA.4.6 has become resistant and is gaining momentum with BA.5, so people with generally weakened immune systems should be more cautious. ” he said.
Based on his research, Ho says only one monoclonal antibody, bebtelovimab, remains effective against the prevalent variant.
“Now, essentially, there’s one antibody left,” he says. “Everything else is gone.”
He said the FDA is very focused on ensuring Covid-19 vaccines are updated, but worries that it hasn’t kept antibody treatments up to date. .
“Millions of people have compromised immune systems and they will be running out of options right now,” he said.