The BA.2 variant is susceptible to certain monoclonal antibodies used to treat COVID-19, such as the Evusheld of AstraZeneca. However, Etesevimab and Bamlanivmab antibodies, which are used as a single treatment, were not able to neutralize the Omicron (BA.2) variant at normal levels in these laboratory tests. And other antibody treatments were also ineffective against Omicron.
Yoshihiro Kawaoka, a virologist at the UW School of Veterinary Medicine and the University of Tokyo, and his team did the research and found out these results. The BA.2 Omicron variant is associated with the more common BA.1 Omicron virus, and some evidence suggests that BA.2 may spread more rapidly than the already highly contagious BA.1 variant.
“The bottom line is we have antibodies that appear to be more effective against BA. 2 compared with BA.1 or BA.1.1. That’s good news, but we don’t know whether what we found in in the lab translates into clinical settings,” says Kawaoka, who previously tested how the BA.1 variant responds to treatments. “We also tested clinically available antiviral compounds, and they are all highly efficacious.”
Kawaoka and his team published their findings in the New England Journal of Medicine on March 9.
In laboratory experiments using non-human primate cells, Kawaoka’s team tested seven monoclonal antibodies, three combinations of antibodies, and three antiviral therapies against the BA.2 variant. Most clinically approved antibody therapies are a combination of several antibodies.
The intravenous drug remdesivir and the active ingredients in two anti-COVID-19 pills, Paxlovid and Merck’s molnupiravir, were somewhat effective against BA.1 as they are against the original COVID-19.
The most effective antibody treatment against the BA.2 variant is Evusheld, which is approved in the United States to help prevent the development of COVID-19 infection in individuals. Antibodies by Regeneron and GlaxoSmithKline were more effective against BA.2 than against the BA.1 Omicron variant, although they were not as potent against BA.2 against earlier variants of the virus.
Available anti-COVID-19 therapies are less effective against newer variants than they were against the original virus strain because they were designed and tested against earlier versions of the virus. Researchers and pharmaceutical companies can design and test treatments against new variants, but that process can take months or years.
The original work was supported in part the National Institutes of Health (grants HHSN272201400008C and 75N93021C00014). This study was also supported by the Japan Research Program on Emerging and Reemerging Infectious Diseases (grants JP20fk0108412, JP21fk0108615 and JP21fk0108104), a Project Promoting Support for Drug Discovery (grant JP20nk0101632), the Japan Program for Infectious Diseases Research and Infrastructure (grant JP21wm0125002), and a Grant-in-Aid for Emerging and Reemerging Infectious Diseases from the Ministry of Health, Labor, and Welfare, Japan (grant 20HA2007).
Source: Medindia
