Brii Biosciences Limited announced that the Center for Drug Evaluation of the National Medical Products Administration of China granted Breakthrough Therapy Designations for BRII-877 (tobevibart), a broadly neutralizing monoclonal antibody targeting hepatitis B virus ("HBV"), and BRII-835 (elebsiran), an investigational HBV-targeting small interfering ribonucleic acid, on May 14, 2024. This represents another milestone in the Company's pursuit of a functional cure for HBV, following the Breakthrough Therapy Designation granted for BRII-179, a recombinant protein-based HBV immunotherapeutic, in November 2023. The Breakthrough Therapy Designation for BRII-877 (Tobevibart) was supported by Phase 1 and 2 studies conducted by Vir Biotechnology Inc. ("Vir") and the Company.

By the end of September 2023, more than 350 people living with HBV have received treatment of BRII-877 (tOBevibart). Data have shown BRII-877 (t Obevibart) to be well-tolerated and to have resulted in marked decreases in hepatitis B surface antigen levels suggesting the potential for BRII-877(tobevibart) to be an important part of a treatment regimen for people living with chronic HBV infection and hepatitis D virus ("HDV") infection. The Breakthrough Therapy Designated for BRII-835 (ebsiran) was supported by Phase 1 & 2 studies conducted by the Company and its partner Vir.

By the end of September2023, more than 570 people living with HBV have participated in clinical studies where BRII-835 (elbsiran) has been shown to be well-toleration and has demonstrated direct antiviral activity against HBV in participants with chronic HBV and HDV infection. Having three breakthrough therapeutic modalities puts the Company in a unique position to address the broader populations of HBV infections including co-infection with HDV. As part of the Company's approach to developing a functional cure for HBV.

the Company and its partner Vir are progressing plans to initiate multiple combination studies in 2024 to further optimize the curative regimens that will inform the Company's registration strategy to bring the best regimens to HBV patients.