Amubarvimab and romlusevimab are non-competing SARS-CoV-2 monoclonal neutralizing antibodies derived from convalesced COVID-19 patients developed in collaboration with the 3rd People’s Hospital of Shenzhen and Tsinghua University. They have been specifically engineered to reduce the risk of antibody-dependent enhancement and prolong the plasma half-lives for potentially more durable treatment effect.

On December 8, 2021, the National Medical Products Administration (NMPA) of China approved the amubarvimab/romlusevimab combination for the treatment of adults and pediatric patients (age 12-17 weighing at least 40 kg) with mild and normal type of COVID-19 at high risk for progression to severe disease, including hospitalization or death. The indication of pediatric patients (age 12-17 weighing at least 40 kg) is under a conditional approval.

In March 2023, Brii Bio made the decision to discontinue the amubarvimab/romlusevimab combination program and has stopped manufacturing efforts in order to redirect resources to high-priority programs. This determination is based on constantly evolving COVID-19 trends and policy updates, as well as protracted regulatory inspections at our contract development and manufacturing organization (CDMO) sites.

The Company is working with the U.S. FDA to withdraw the Emergency Use Authorization (EUA) application  at an appropriate time following the completion of activities required by regulatory authorities and also with the China NMPA to withdraw the Biologics License Application (BLA) in the third quarter of 2023 once all necessary regulatory requirements have been completed.