● Key B-Well data show a significant 19% functional cure rate in the overall study population, with the rate reaching 26% in patients with lower viral activity, compared to 0% in patients receiving only standard of care;^[1]

 

● Among them, data from the Chinese subgroup show a functional cure rate of up to 35% in patients with a baseline HBsAg ≤ 1000 IU/mL; 

 

● In an exploratory analysis, 49% of bepirovirsen-treated subjects had their surface antigen levels reduced to ≤100 IU/mL one year after treatment cessation. 

 

On May 28, GlaxoSmithKline (LSE/NYSE: GSK) announced positive pivotal data for bepirovirsen, an antisense oligonucleotide (ASO) drug for the treatment of chronic hepatitis B (CHB). The results of two Phase III clinical trials, B-Well 1 (NCT05630807) and B-Well 2 (NCT05630820), were simultaneously published in the New England Journal of Medicine and presented at the European Association for the Study of the Liver (EASL) Congress. On May 11, Chia Tai Tianqing, a core enterprise of Sino Biopharmaceutical (1177.HK), entered into an exclusive strategic cooperation with GlaxoSmithKline (GSK) to accelerate the marketing process of bepirovirsen in China. 

 

Combined data from the two trials showed that 6 months of bepirovirsen treatment achieved a statistically significant and clinically meaningful functional cure rate of 19% in the overall study population (HBsAg levels ≤3000 IU/ml) (233/1220 vs. 0/614 placebo group[i], p<0.001 for both trials), meeting the primary endpoint. A key secondary endpoint showed that among subjects with HBsAg ≤1000 IU/ml, the functional cure rate reached 26% (200/768 vs. 0/393 placebo group, p<0.001 for both trials). This patient group accounts for approximately 45% of diagnosed chronic hepatitis B cases worldwide. ^[2] Current standard of care typically requires lifelong medication, with a functional cure rate of less than 1%. ^[3]

 

Functional cure is defined as the sustained absence of detectable hepatitis B virus DNA and HBsAg in the blood for at least 6 months after stopping all treatment. This indicates that the immune system can control the infection without the need for medication. ^[4] A decrease in HBsAg is also associated with an 89% reduction in the risk of hepatic cancer and a 62% reduction in the risk of all-cause death. ^[5] Notably, in an exploratory analysis, 49% of bepirovirsen-treated subjects had their quantitative surface antigen levels (qHBsAg) reduced to ≤100 IU/mL one year after treatment cessation. Medical literature suggests that such low surface antigen levels are associated with enhanced immune control and improved patient outcomes ^[6]. Additionally, a key secondary endpoint showed that 23% of all subjects (283/1220 vs. 0/614 placebo group, p<0.001 for both trials) and 31% of subjects with baseline HBsAg ≤1000 IU/mL (237/768 vs. 0/393 placebo group, p<0.001 for both trials) achieved sustained hepatitis B virus DNA below the lower limit of quantification (<LLOQ) at week 72, after stopping all treatment at week 48. 

 

These trials all demonstrated an acceptable safety and tolerability profile for bepirovirsen, with the three most common adverse reactions being injection site erythema, local pain, and transient increases in hepatic enzymes in the blood. 

 

Functional Cure Rates at Week 72 in B-Well 1 and B-Well 2 Patient Groups

 

 

On the 28th, regional subgroup data were presented in an oral report at EASL. Among them, data from the Chinese subgroup showed a functional cure rate of 24% in subjects with HBsAg ≤3000 IU/ml, and 35% in subjects with HBsAg ≤1000 IU/ml. 

 

Chronic hepatitis B affects over 240 million people worldwide ^[7] and causes more than half of all hepatic cancer cases globally ^[8]. For the first time, bepirovirsen offers the potential to surpass current standard therapies, significantly increasing the functional cure rate while reducing the risk of long-term liver complications such as cancer.
 
Currently, efforts related to the testing, diagnosis, and treatment of chronic hepatitis B are underway in multiple countries and regions, including China and the US, with a commitment to incorporating functional cure as a treatment goal in clinical guidelines. 

 

Professor Hou Jinlin

Director of the Institute of Hepatology, Guangdong Province

First Author of the New England Journal of Medicine Manuscript

 

"The current standard of care for chronic hepatitis B places a significant burden on patients and healthcare systems, and rarely achieves a functional cure. With guidelines now prioritizing functional cure ^[4], the release of this new data is epoch-making for the treatment of chronic hepatitis B. Combined with more advanced testing and diagnostic technologies, this innovative therapy has the potential to improve the lives of millions of patients with chronic hepatitis B."

 

Currently, bepirovirsen is undergoing Priority Review by the U.S. Food and Drug Administration (FDA) and has been granted Breakthrough Therapy and Fast Track designations. Bepirovirsen is also under review by regulatory authorities in Europe, Japan (SAKIGAKE designation), and China (included in the Breakthrough Therapy and Priority Review programs). GSK expects to receive the first regulatory decision in the third quarter of 2026. 

 

About the B-Well 1 and B-Well 2 Clinical Trials

 

B-Well 1 and B-Well 2 are global, multicenter, randomized, double-blind, controlled trials conducted in 29 countries worldwide. The trials are designed to evaluate the efficacy, safety, pharmacokinetic characteristics, and durability of functional cure with bepirovirsen in subjects with chronic hepatitis B treated with nucleos(t)ide analogues (NAs) and with a baseline surface antigen (HBsAg) ≤3000 IU/ml. The primary endpoint assesses the proportion of subjects with a baseline surface antigen (HBsAg) ≤3000 IU/ml who achieve functional cure. A key secondary endpoint evaluates the achievement of functional cure in subjects with a baseline surface antigen (HBsAg) ≤1000 IU/ml. Functional cure is defined as the sustained absence of detectable hepatitis B DNA and hepatitis B surface antigen (HBsAg) in the blood for at least 24 weeks after stopping all treatment, indicating that the immune system can control the infection without the need for further medication. 

 

About Chronic Hepatitis B

 

Hepatitis B is a hepatic infection caused by a virus that can lead to acute or chronic liver disease. Chronic hepatitis B occurs when the immune system cannot clear the virus, leading to a long-term infection that affects over 240 million people globally, including approximately 75 million in China. The disease causes approximately 1.1 million deaths annually and is responsible for about 56% of global hepatic cancer cases. Currently, many patients often require lifelong antiviral therapy to suppress the virus, making functional cure a key goal in the management of the disease. 

 

About Bepirovirsen

 

Bepirovirsen is an investigational antisense oligonucleotide (ASO) that can recognize and inhibit the production of the genetic material (i.e., RNA) of the hepatitis B virus that causes chronic infection, thereby potentially enabling the human immune system to regain control. Bepirovirsen reduces the production of HBV-related RNA and viral proteins, lowers the level of hepatitis B surface antigen (HBsAg) in the blood, and stimulates the immune system to increase the chance of a durable response. 

 

References:

[1] Hou JL, Lim SG, Buti M, et al.Phase 3 results of bepirovirsen treatment for chronic hepatitis B virus infection" in New England Journal of Medicine, May 2026. DOI: 10.1056/NEJMoa2515131; Seng-Gee Lim et al, "Clinically meaningful rates of functional cure in virologically suppressed patients with chronic hepatitis B infection treated with bepirovirsen: B-Well Phase 3 Trials" presentation at EASL, 28 May 2026. 

[2] GSK data on file, 2026

[3] Slaets, L. et al.“Systematic review with meta-analysis: hepatitis B surface antigen decline and seroclearance in chronic hepatitis B patients on nucleos(t)ide analogues or pegylated interferon therapy” in GastroHep 2, 106–116 (2020)

[4] EASL, “Clinical Practice Guidelines on the management of hepatitis B virus infection” in Journal of Hepatology, Volume 83, Issue 2, August 2025, Pages 502-583.Available at: https://www.sciencedirect.com/science/article/pii/S0168827825001746 (last accessed: May 2026).

[5] Drysdale M. et al, “Association of Hepatitis B Surface Antigen Loss with Long-Term Clinical Outcomes among Patients with Chronic Hepatitis B Infection: A US Based Retrospective Cohort Study Using Optum Electronic Health Records Database” in Z Gastroenterol 2025; 63(08): e481, DOI: 10.1055/s-0045-1810830

[6] Kim, J.H., et al.“Circulating serum HBsAg level is a biomarker for HBV-specific T and B cell responses in chronic hepatitis B patients.Sci Rep 10, 1835 (2020).

[7] WHO, Global hepatitis report 2026, April 2026

[8] Rumgay H et al."Global burden of primary liver cancer in 2020 and predictions to 2040", in J Hepatol.2022;77:1598–1606.doi: 10.1016/j.jhep.2022.08.021

Notes:

[i] The bepirovirsen group received bepirovirsen in combination with standard of care, and the placebo group received placebo in combination with standard of care. 

[ii] Defined as HBsAg not detected (quantitative; < 0.05 IU/mL) and HBV DNA < LLOQ (< 20 IU/mL or target not detected)

[iii] Absolute values for the bepirovirsen group versus the placebo group, respectively. 

Declaration:

1. This press release is intended to facilitate the communication and exchange of medical information and is for reference by healthcare professionals only. It is not for advertising purposes. 

2. The company does not recommend any drugs and/or indications. 

3. The information contained in this press release is for reference only and cannot replace professional medical guidance in any way, nor should it be considered as a diagnosis or treatment recommendation. If you wish to understand specific disease diagnosis and treatment information, please follow the advice or guidance of a physician or other healthcare professional.