Antivirals, some antibodies, work well against BA.2 omicron variant of COVID-19 virus

Date:
March 10, 2022
Source:
University of Wisconsin-Madison
Summary:
The antiviral therapies remdesivir, molnupiravir, and the
active ingredient in Pfizer's Paxlovid pill (nirmatrelvir),
remain effective in laboratory tests against the BA.2 variant
of SARS-CoV-2, the virus that causes COVID-19, according to new
research.



FULL STORY ==========================================================================
The antiviral therapies remdesivir, molnupiravir, and the active
ingredient in Pfizer's Paxlovid pill (nirmatrelvir), remain effective
in laboratory tests against the BA.2 variant of SARS-CoV-2, the virus
that causes COVID-19.


==========================================================================
The BA.2 variant also remains susceptible to at least some of the
monoclonal antibodies used to treat COVID-19, such as Evusheld by
AstraZeneca. However, the antibodies etesevimab and bamlanivmab, which
are used together as a single treatment, were not able to neutralize the
BA.2 virus at common dosages in these lab tests. Other antibody treatments
were less effective against BA.2 than they are against earlier strains
of SARS-COV-2.

These results come from new research led by Yoshihiro Kawaoka, a
virologist at the UW School of Veterinary Medicine and the University
of Tokyo. The BA.2 omicron variant is related to the more common BA.1
omicron virus, and some evidence suggests that BA.2 can spread more
quickly 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 collaborators at UW-Madison and the National Institute of Infectious Diseases in Tokyo published their findings in the New England Journal
of Medicine on March 9.

In lab experiments using non-human primate cells, Kawaoka's team tested
seven monoclonal antibodies, three combinations of antibodies, and three antiviral treatments against the BA.2 variant. Most clinically approved antibody treatments are a combination of multiple antibodies.

The intravenous drug remdesivir and the active ingredients in two
anti-COVID-19 pills, Paxlovid and Merck's molnupiravir, were nearly
as effective against BA.1 as they are against the original strain of SARS-CoV-2.

The most effective antibody treatment against the BA.2 variant
was Evusheld, which is approved in the U.S. to help prevent COVID-19
infection in people vulnerable to severe disease. The antibodies sold
by Regeneron and GlaxoSmithKline were much more effective against BA.2
than they are against the BA.1 omicron variant, although they were not
as potent against BA.2 as they are against earlier versions of the virus.

Available anti-COVID treatments are typically less effective
against new variants than they are 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 takes months.

This work was supported in part the National Institutes of Health (grants HHSN272201400008C and 75N93021C00014). The 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).


========================================================================== Story Source: Materials provided
by University_of_Wisconsin-Madison. Original written by Eric
Hamilton. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Emi Takashita, Noriko Kinoshita, Seiya Yamayoshi, Yuko Sakai-Tagawa,
Seiichiro Fujisaki, Mutsumi Ito, Kiyoko Iwatsuki-Horimoto,
Peter Halfmann, Shinji Watanabe, Kenji Maeda, Masaki Imai,
Hiroaki Mitsuya, Norio Ohmagari, Makoto Takeda, Hideki Hasegawa,
Yoshihiro Kawaoka.

Efficacy of Antiviral Agents against the SARS-CoV-2 Omicron
Subvariant BA.2. New England Journal of Medicine, 2022; DOI:
10.1056/NEJMc2201933 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/03/220310170830.htm

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