FDA Scales Back Sotrovimab Use for High-Risk COVID

The FDA on Wednesday quietly limited the use of another monoclonal antibody for COVID-19 after data showed considerably lower neutralization against the Omicron BA.2 subvariant.

In a revised emergency use authorization (EUA) letter to manufacturer GlaxoSmithKline, the FDA said that sotrovimab is not authorized to treat mild to moderate COVID “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.”

Based on prior precedent from the Department of Health and Human Services (HHS) when limiting other monoclonal antibodies for Omicron, this could apply to areas where BA.2 has over 80% prevalence.

A fact sheet for healthcare providers revealed a 16-fold reduction in neutralization against BA.2 versus the Omicron strain, with the agency noting that the “clinical relevance of the 16-fold reduction in susceptibility is unknown.”

That data came from a pre-print in bioRxiv on February 18, funded by sotrovimab developers Vir Biotechnology and GlaxoSmithKline, which found that “a moderate shift in activity (16-fold change in IC₅₀ [half-maximal inhibitory concentration]) was observed for the Omicron BA.2 variant.”

A prior pre-print from researchers at Columbia University in New York City showed sotrovimab had a 27-fold reduction in neutralizing activity against BA.2 versus BA.1. Pre-print data from NYU researchers showed similar declines in activity.

With this move by the FDA, only Eli Lilly’s bebtelovimab remains authorized to treat high-risk COVID patients with BA.2.

NIH COVID guidelines currently recommend antiviral nirmatrelvir/ritonavir (Paxlovid) as the top choice for individuals with mild to moderate COVID at high risk of progressing to severe disease.