Brii Biosciences Limited announced new live virus data confirming that the amubarvimab/romlusevimab combination, a long-acting COVID-19 monoclonal antibody (mAb) therapy, retains neutralizing activity against the Omicron BA.4/5 and BA.2.12.1 SARS-CoV-2 subvariants. Data from the live virus neutralization assay performed at a University of Maryland lab certified by the U.S.National Institutes of Health (NIH) and National Institute of Allergy and Infectious Diseases (NIAID) predict that total serum concentrations of the amubarvimab/romlusevimab combination will remain greater than 170 times the level required for greater than 90% neutralization (Neut99: 0.94 µg/mL) against the live virus, 14 days post dose. As a result, adequate therapeutic exposures are expected to persist throughout the treatment period. The mutations found in the BA.4/5 and BA.2.12.1 subvariants spike protein confer a limited reduction in neutralization activity from wild-type SARS-CoV-2. Based on the human pharmacokinetic data gathered on the amubarvimab/romlusevimab combination, exposures of intravenous amubarvimab 1,000mg and romlusevimab 1,000mg are expected to remain above the level required for neutralizing activity against BA.4/5 and BA.2.12.1, for the treatment of COVID-19.

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. On March 15, 2022, the National Health Commission of China added the amubarvimab/romlusevimab combination to its COVID-19 Diagnosis and Treatment Guidelines (9th Pilot Edition) for the treatment of COVID-19.

On July 7, 2022, the amubarvimab/romlusevimab combination was made commercially available in China. The U.S. FDA is currently reviewing Brii Bio's Emergency Use Authorization application for the amubarvimab/romlusevimab combination.