FDA Revokes Emergency Use Authorization for GSK/Vir’s Sotrovimab Due to Ineffectiveness Against Omicron BA.2

Compiled by Tom Li

The U.S. FDA recently announced that due to the increasing proportion of COVID-19 cases caused by the Omicron subvariant BA.2 across the United States, it has decided to revoke the authorization for the monoclonal antibody (mAbs) Xevudy (sotrovimab), developed by GSK and its partner Vir Biotechnology, for the treatment of COVID-19 in any region of the United States.

According to the forecast data released by the U.S. Centers for Disease Control and Prevention (CDC) on April 5, 2022, it is estimated that in all Health and Human Services (HHS) regions of the United States, the proportion of COVID-19 cases caused by the Omicron BA.2 variant has exceeded 50%. Data from the Fact Sheet for Healthcare Providers issued by the U.S. FDA shows that the previously authorized dose of Xevudy is unlikely to be effective in treating the BA.2 variant.

In response, the U.S. FDA will continue to monitor the situation of the BA.2 variant across the country and provide subsequent communication measures as appropriate. The U.S. FDA recommends that healthcare providers use alternative therapies such as Paxlovid, Veklury, bebtelovimab, and molnupiravir, all of which have been previously authorized or approved for treating mild to moderate COVID-19 patients at high risk of progressing to severe disease, including hospitalization or death.

Notably, the FDA's conclusion that the therapy is nearly ineffective against the BA.2 variant starkly contrasts with the trial data released by GlaxoSmithKline (GSK) just in February this year. At that time, GSK and Vir Biotechnology claimed that their monoclonal antibody therapy, Xevudy, was effective against the Omicron BA.2 sub-variant. GSK stated that, based on pseudovirus and extensive pharmacokinetic data, a 500mg dose of sotrovimab was sufficient to maintain neutralizing activity against the Omicron BA.2 sub-variant. Additionally, Xevudy was shown to reduce the risk of hospitalization and death in patients with mild to moderate COVID-19 by 79%.

As of April 5, 2022, Xevudy remains authorized for treatment in Europe. During the COVID-19 pandemic, if trial data indicates that certain antibody products are no longer effective against the virus, or new variants may prompt regulatory agencies to withdraw previously approved therapies. Reportedly, the U.S. FDA had earlier announced the halt of Xevudy's use in several northeastern states, later expanding the restrictions to about half of the country, and it is now completely banned across the United States.

For GSK and Vir, the FDA's pause on the use of Xevudy across the U.S. means that the future sales of this therapy will be severely impacted. In 2021, Xevudy generated revenue of £958 million ($1.26 billion). As for 2022, GSK had previously optimistically projected that Xevudy could generate £1.4 billion ($1.83 billion) in revenue, but due to this negative factor, its actual sales are likely to fall short of this expectation.

Notably, GSK and Vir Biotechnology are not the only biopharmaceutical companies to have suffered setbacks due to the uncertainties of the pandemic. According to records from the U.S. FDA, antibody drugs from Eli Lilly and Regeneron have also been shelved for the same reason. Meanwhile, antiviral drugs from Merck and Pfizer remain in normal use, and AstraZeneca's Evusheld has recently received FDA approval for pre-exposure prophylaxis in individuals with weakened immune systems or those unable to receive the COVID-19 vaccine.

Reference Source:

1、FDA: Sotrovimab No Longer Authorized to Treat COVID-19 in Any US Region

2、GSK, Vir's COVID antibody put on ice as BA.2 subvariant takes hold