Brii Biosciences Adds US$100 Million to Advance its Late-Stage Monoclonal Antibody Combination Therapy, BRII-196/BRII-198, for Non-Hospitalized COVID-19 Patients

DURHAM,N.C. and BEIJING,Sept. 7,2021 -- Brii Biosciences Limited("Brii Bio" or the "Company",stock code: 2137.HK) a multi-national company developing innovative therapies for diseases with significant unmet medical needs and large public health burdens,today announced that the Company is committing an additional US$100 million to advance global regulatory filings and commercial efforts for its investigational SARS-CoV-2 (virus that causes COVID-19) combination therapy,BRII-196/BRII-198 ("combination BRII-196/BRII-198").

"Following on the heels of a positive Phase 3 data readout from the ACTIV-2 trial,and as countries around the world continue to face a significant resurgence of COVID-19 cases,we are doubling down on our efforts to bring BRII-196/BRII-198 to a broad range of patients as a promising potential new treatment option for COVID-19," said Zhi Hong,Ph.D.,Chairman and CEO of Brii Biosciences. "This investment reinforces the Company's mission,building on the highly effective clinical outcomes,as we accelerate our strategic efforts to pursue regulatory filings,expand manufacturing and supply capabilities and establish key collaborations in both established and emerging global markets to pave a clear and compelling path to commercialization."

BRII-196/BRII-198 is a SARS-CoV-2 neutralizing monoclonal antibody combination therapy. Interim results from Phase 3 of the NIH-sponsored ACTIV-2 trial recently demonstrated that the combination therapy achieved a statistically significant reduction,78%,of relative risk in the combined endpoint of hospitalization and death in non-hospitalized COVID-19 patients at high risk of clinical progression (nominal one-sided p value = 0.00001) with significantly less frequent grade three or above adverse events compared with placebo. Following the clear demonstration of both clinical and safety outcomes,the independent data safety monitoring board (DSMB) permitted the early release of the interim results while the complete study follow-up remains ongoing.

This study was conducted at clinical trial sites around the world,including the United States,Brazil,South Africa,Mexico,Argentina and the Philippines,with patients enrolled between January and July of 2021 – a period of rapid global emergence of novel SARS-CoV-2 variants. Data on the clinical efficacy of combination BRII-196/BRII-198 by variant type will also be evaluated as part of the study. Current in vitro pseudovirus testing data suggests that combination BRII-196/BRII-198 retains activity against major SARS-CoV-2 variants of concern,including the following commonly identified variants,B.1.1.7 (Alpha),B.1.351 (Beta),B.1.617.2 (Delta),B.1.429 (Epsilon),P.1 (Gamma),C.37 (Lambda),and B.1.621 (Mu).

About BRII-196 and BRII-198

BRII-196 and BRII-198 are non-competing SARS-CoV-2 monoclonal neutralizing antibodies derived from convalesced COVID-19 patients. They have been specifically engineered to reduce the risk of antibody-dependent enhancement,enhance antibody penetration to the lung and prolong the plasma half-lives for potentially more durable treatment effect. Their non-overlapping epitope binding regions provide a high degree of neutralization activity against SARS-CoV-2.

Investigational New Drug (IND) applications have been submitted for the combination therapy to the U.S. Food and Drug Administration (FDA),the China National Medical Products Administration (NMPA) and the Department of Health in Hong Kong,China. The combination of BRII-196/BRII-198 was generally safe and well tolerated in Phase 1 studies,supporting evaluation in later stage studies. In addition to the collaboration with NIAID,Brii Biosciences is conducting additional studies in China,evaluating the pharmacokinetics and safety of combination BRII-196/BRII-198 as well as a Phase 2 efficacy study of combination BRII-196/BRII-198 for the treatment of COVID-19.

About Brii Biosciences

Brii Biosciences Limited ("Brii Biosciences",or the "Company",stock code: 2137.HK) is a biotechnology company based in China and the United States committed to advancing therapies for significant infectious diseases,such as hepatitis B virus (HBV),human immunodeficiency virus (HIV),multi-drug resistant (MDR) or extensive drug resistant (XDR) gram-negative infections,and other illnesses,such as the central nervous system (CNS) diseases,which have significant public health burdens in China and worldwide. For more information,visit www.briibio.com.

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