Brii Biosciences Limited a biotechnology company developing therapies to improve patient health and choice across diseases with high unmet need, today announced that the Center for Drug Evaluation (CDE) of the National Medical Products Administration (NMPA) granted Breakthrough Therapy Designations for BRII-877 (tobevibart), an investigational broadly neutralizing monoclonal antibody targeting hepatitis B virus (HBV) and BRII-835 (elebsiran), an investigational HBV-targeting small interfering ribonucleic acid (siRNA). 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 ("Vir", Nasdaq: VIR) and Brii Bio. As of September 2023, more than 350 people living with HBV have received treatment of BRII-877 (tobevibart). Data has shown BRII-877 (tobevibart) to be well-tolerated and to have resulted in marked decreases in HBsAg 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 chronic hepatitis D virus (HDV) infection. The Breakthrough Therapy Designation for BRII-835 (elebsiran) was supported by Phase 1 and 2 studies conducted by Brii Bio and its partner Vir. As of September 2023, more than 570 people living with HBV have participated in clinical studies where BRII-835 (elebsiran) has been shown to be well-tolerated and has demonstrated direct antiviral activity against HBV in participants with chronic HBV and HDV infection.

"Receiving Breakthrough Therapy Designations for BRII-877 and BRII-835 as well as the earlier Breakthrough Therapy Designation for BRII-179 further supports our long-held scientific rationales in the development of functional cure combination regimens for patients with chronic HBV infection," said Dr. Qing Zhu, Head of China R&D, Brii Bio. "Brii Bio and our partner Vir Biotechnology have conducted numerous clinical trials over the past five years, from which we have gained comprehensive clinical safety and efficacy data as well as critical insight towards our late-stage development plan and achieving potentially higher rates of HBV functional cure in broader patient populations."

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 Brii Bio'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.