Brii Biosciences Announces Two Breakthrough Therapy Designations for BRII-877 and BRII-835 Building on Extensive Clinical Evidence from Multiple Phase 2 Studies

DURHAM, N.C. and BEIJING, May 14, 2024 /PRNewswire/ -- Brii Biosciences Limited ("Brii Bio" or the "Company", stock code: 2137.HK), 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.

About Hepatitis B

Hepatitis B viral infection (HBV) is one of the world's most significant infectious disease threats with more than 254 million people infected globally.¹ Chronic HBV infection is the leading cause of liver disease and an estimated 820,000 people die of complications from chronic HBV each year.¹ HBV is of exceptional concern in China, where 87 million people are infected.²

About Hepatitis D

Hepatitis D is a liver inflammation caused by the hepatitis D virus (HDV), which relies on hepatitis B virus (HBV) for replication. This infection can only occur in the presence of HBV. The combination of HDV-HBV co-infection is considered the most severe form of chronic viral hepatitis, leading to a quicker progression towards hepatocellular carcinoma and liver-related death. Globally, nearly 5% of individuals with chronic HBV infection are affected by HDV. HDV infection can occur through either simultaneous infection with both hepatitis B and D (co-infection) or acquiring hepatitis D after already having hepatitis B (super-infection).³

About BRII-877 (Tobevibart)

BRII-877 (tobevibart) is an investigational subcutaneously administered neutralizing monoclonal antibody designed to block entry of HBV and HDV into hepatocytes and also to reduce the level of virions and subviral particles in the blood. BRII-877 (tobevibart), which incorporates Xencor's Xtend™ and other Fc technologies, has been engineered to potentially function as a T-cell vaccine against HBV and HDV, as well as to have an extended half-life. Brii Bio licensed exclusive rights to develop and commercialize BRII-877 (tobevibart) for the greater China territory from Vir Biotechnology, Inc. ("Vir") in 2022.

About BRII-835 (Elebsiran)

BRII-835 (elebsiran) is an investigational subcutaneously administered HBV-targeting siRNA that has the potential to stimulate an effective immune response and has direct antiviral activity against HBV and HDV. It is the first siRNA in the clinic to include Enhanced Stabilization Chemistry Plus (ESC+) technology to enhance stability and minimize off-target activity, which potentially can result in an increased therapeutic index. Brii Bio licensed exclusive rights to develop and commercialize BRII-835 (elebsiran) for the greater China territory from Vir Biotechnology, Inc. ("Vir") in 2020.

About BRII-179

BRII-179 is a novel recombinant protein-based HBV immunotherapeutic candidate that expresses the Pre-S1, Pre-S2, and S HBV surface antigens, and is designed to induce enhanced and broad B-cell and T-cell immunity. Brii Bio licensed BRII-179 from VBI Vaccines, Inc. ("VBI") in December 2018 and has extended the exclusive license to global rights since July 2023.

About Brii Bio

Brii Biosciences Limited ("Brii Bio", stock code: 2137.HK) is a biotechnology company developing therapies to address major public health challenges where patients experience high unmet medical needs, limited choice and significant social stigmas. With a focus on infectious and central nervous system diseases, the Company is advancing a broad pipeline of unique therapeutic candidates with lead programs against hepatitis B viral infection (HBV). The Company is led by a visionary and experienced leadership team and has operations in key biotech hubs, including Raleigh-Durham, the San Francisco Bay Area, Beijing and Shanghai. For more information, visit www.briibio.com.

[1] World Health Organization. (April 2024). Global hepatitis report 2024: action for access in low- and middle-income countries. World Health Organization. Retrieved from https://www.who.int/publications/i/item/9789240091672 

[2] World Health Organization. Hepatitis. World Health Organization. Retrieved from https://www.who.int/china/health-topics/hepatitis#:~:text=There%20are%2087%20million%20people,living%20with%20chronic%20hepatitis%20C. 

[3] World Health Organization. (July 2023). Hepatitis D. World Health Organization. Retrieved from https://www.who.int/news-room/fact-sheets/detail/hepatitis-d

source: Brii Biosciences Limited