The SARS-CoV-2 virus has now had ample time to mutate, as reports of the proliferation of multiple variants make clear, and the U.S. FDA’s Tim Stenzel said the agency is now focused on three variants, including one recently reported from Israel. Stenzel said on the latest COVID-19 testing town hall that one of the key concerns regarding existing authorized tests is the potential for loss of sensitivity, a problem the agency hopes to overcome without the use of live virus.

Marking the first time monoclonal antibodies developed by separate companies will be tested in combination against COVID-19, Vir Biotechnology Inc.’s VIR-7831 will be added to Eli Lilly and Co.’s bamlanivimab in the ongoing phase II BLAZE-4 study in low-risk patients with mild to moderate disease. The collaboration comes as early research indicates some antibodies in development appear to lose activity when pitted against emerging SARS-CoV-2 variants. VIR-7831 (also known as GSK-4182136), partnered with Glaxosmithkline plc, is designed to bind to a different epitope of the SARS-CoV-2 spike protein than bamlanivimab. A dual-action antibody, VIR-7831 is designed to both block viral entry into healthy cells and clear infected cells.