REGN - AstraZeneca COVID-19 therapy offers less protection against newer Omicron strains: Study

A newly published study indicates that Evusheld, a monoclonal antibody therapy developed by AstraZeneca ( NASDAQ: AZN ) which is available in the U.S. for pre-exposure prophylaxis of COVID-19 might be less effective against new sub lineages of Omicron.

The study was designed to evaluate the neutralizing activity of different FDA-approved monoclonal antibodies as single agents and in combination against Omicron subvariants BA.2.12.1, BA.4, and BA.5.

According to results published on the New England Journal of Medicine on Wednesday, Evusheld, a combination of antibodies tixagevimab and cilgavimab neutralized the variants albeit with a low neutralizing effect.

Meanwhile, Regeneron’s ( REGN ) antibody combo, casirivimab and imdevimab also inhibited the sub lineages despite indicating a reduced neutralizing activity, the researchers pointed out. According to data, COVID-19 therapy sotrovimab developed by GSK (GSK) and Vir Biotechnology ( VIR ) also lost inhibitor activity against the variants.

A few months ago, the developers pulled casirivimab/ imdevimab and sotrovimab from the U.S. market as BA.4, and BA.5. subvariants were gaining ground.

“However, in clinical use, these variants may be less susceptible to combination therapy with casirivimab and imdevimab and with tixagevimab and cilgavimab,” the researchers wrote in the peer-reviewed article.

Nevertheless, bebtelovimab, a new antibody developed by Eli Lilly ( LLY ) and AbCellera Biologics ( ABCL ) efficiently neutralized BA.2.12.1, BA.4, and BA.5, the researchers observed.

They added that Gilead’s ( GILD ) COVID-19 infusion remdesivir, and the oral COVID-19 drugs developed by Pfizer ( PFE ) and Merck ( MRK )/ Ridgeback Biotherapeutics could offer neutralizing activity against the newer Omicron variants.

“Overall, our data suggest that the three small-molecule antiviral drugs remdesivir, molnupiravir, and nirmatrelvir may have therapeutic value against the sublineages BA.2.12.1, BA.4, and BA.5 of SARS-CoV-2 omicron variants,” the investigators concluded.

However, the team of researchers from the University of Wisconsin -Madison, Johns Hopkins and Icahn School of Medicine at Mount Sinai, and Tokyo, Japan highlighted the lack of clinical data as the main limitation of the study.

In June, citing pre-clinical data, AstraZeneca ( AZN ) noted the neutralizing activity of Evusheld against BA.4 and BA.5 which became dominant COVID-19 variants in the U.S. late last month.

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