On Mar. 25, 2022, GlaxoSmithKline and Vir Biotechnology announced that the US Food and Drug Administration (FDA) had amended the Emergency Use Authorization (EUA) Fact Sheet for sotrovimab, an investigational monoclonal antibody.

The FDA had determined that, based on the totality of available evidence, including new live virus data generated by Vir, it is unlikely that the sotrovimab 500 mg dose will be effective against the Omicron BA.2 variant. GSK and Vir were preparing a package of data in support of a higher dose of sotrovimab for the Omicron BA.2 subvariant and shared these data with regulatory and health authorities around the world for discussion.

The FDA has updated its website to exclude sotrovimab use in geographic regions where infection is likely to have been caused by a non-susceptible SARS-CoV-2 variant based on available information, including variant susceptibility to these drugs and regional variant frequency (HHS regions 1 and 2). The FDA will continue to monitor the prevalence of circulating variants and update its website accordingly.

Sotrovimab is an investigational SARS-CoV-2 neutralizing monoclonal antibody. The antibody binds to an epitope on SARS-CoV-2 shared with SARS-CoV-1 (the virus that causes SARS), indicating that the epitope is highly conserved, which may make it more difficult for resistance to develop.

Sotrovimab, which incorporates Xencor, Inc.’s Xtend™ technology, has also been designed to achieve high concentration in the lungs to ensure optimal penetration into airway tissues affected by SARS-CoV-2 and to have an extended half-life.