Eli Lilly, Regeneron antibody therapies lose out against Omicron

German researchers have found that Covid-19 therapies developed by Eli Lilly and Regeneron lose most of their effectiveness when exposed in laboratory tests to the Omicron variant of coronavirus.

The group of Cologne and Berlin-based scientists found that protection from GlaxoSmithKline and Vir’s antibody cocktail Xevudy held up when exposed to Omicron in a lab experiment but that this was not the case for Lilly’s antibodies bamlanivimab and etesevimab and the antibodies in Regeneron’s Ronapreve drug.

“The neutralising activity of several monoclonal antibodies is strongly affected against the Omicron variant and will limit treatment options for Omicron-induced Covid-19,” the study authors said in the paper that was posted online on Tuesday.

The findings have not yet been peer-reviewed for publication in a medical journal.

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Asked about the findings, Ely Lilly said it expected the efficacy of its antibody combination to be lower.

“Due to the substitutions contained within the spike protein of the Omicron variant of concern, it appears that bamlanivimab with etesevimab is likely to experience reduced neutralisation activity,” said a spokesperson.

The company was conducting its own Omicron tests, also including its experimental antibody bebtelovimab, and would report the initial findings as soon as possible.

There was no immediate comment from Regeneron.

Monoclonal antibodies

Last week, in a similar lab analysis, a group of Germany-based researchers including virologist Sandra Ciesek of the University Hospital Frankfurt came to a similar conclusion on the Regeneron drug, saying Omicron was resistant against it.

Regeneron itself said on November 30th that lab tests and computer modelling suggested its Covid-19 antibody drug would have reduced efficacy against the Omicron variant.

GSK and Vir have said lab tests on viruses that carry all of Omicron's mutations indicate that their antibody drug would remain effective against the new variant.

The class of Covid-19 drugs known as monoclonal antibodies – bio-engineered versions of virus-fighting natural proteins – is designed to latch on to the spike protein on the surface of the coronavirus, but Omicron has been found to have an unusually high number of mutations on the spike.

A similar product, AstraZeneca's Evusheld, last week won emergency use authorisation in the United States to prevent Covid-19 before any exposure to the virus, targeting those that respond poorly to vaccines because of a weakened immune system. – Reuters