GSK Canada secures priority review for regulatory submission of bepirovirsen, a potential functional cure treatment for chronic hepatitis B

• The new drug submission for bepirovirsen was granted priority review, underscoring the unmet need for patients
• Submission supported by statistically significant and clinically meaningful functional cure rates in pivotal Phase III B-Well trials
• An estimated 262,000 people in Canada live with chronic hepatitis B, a leading cause of liver cancer¹

MISSISSAUGA, ON, April 30, 2026 /CNW/ - GSK today announced that it has filed a new drug submission for bepirovirsen for regulatory review in Canada.  Bepirovirsen is an investigational antisense oligonucleotide (ASO) for the treatment of adults with chronic hepatitis B (CHB). The submission will be reviewed under the Health Canada priority review policy.

Chronic hepatitis B remains a public health concern in Canada, with an estimated 262,000 people living with CHB.¹ The current standard of care--nucleos(t)ide analogue therapy--typically requires lifelong treatment, and rates of functional cure remain very low, at approximately 1%.² A functional cure is defined as undetectable hepatitis B virus DNA and hepatitis B surface antigen (HBsAg) in the blood for at least 24 weeks after stopping all treatment, indicating that the disease is controlled by the immune system without medication.³ Globally, CHB is estimated to cause roughly 56% of liver cancer cases. ⁴ 

"CHB imposes a significant burden on patients, increasing the risk of liver cancer and other serious liver disease. In Canada, these risks are exacerbated by inequities in screening, access to quantitative hepatitis B surface antigen testing, and connection to care," said Dr. Michelle Horn, Country Medical Director, GSK Canada. "The priority review of bepirovirsen is an important milestone in our efforts to transform care for people living with chronic hepatitis B."

Positive Phase III results from the B‑Well 1 and B‑Well 2 trials support the regulatory submission for bepirovirsen. Bepirovirsen plus standard of care produced statistically significant and clinically meaningful functional cure rates versus standard of care alone across all ranked endpoints. The trials demonstrated an acceptable safety and tolerability profile consistent with what was reported in other studies. The data is planned for presentation at the European Association for the Study of Liver Congress (EASL) and submission to a peer‑reviewed journal later this year.

The priority review designation in Canada reflects bepirovirsen's innovation and potential to address a disease with high unmet medical need. Bepirovirsen's safety and effectiveness are still under investigation, and market authorization has not yet been granted in Canada or any other country. The Canadian regulatory submission follows earlier filings in Japan, China, the European Union, and the United States. In the United States, bepirovirsen received Breakthrough Therapy designation from the Food and Drug Administration.

About chronic hepatitis B

Hepatitis B is a viral infection that can cause both acute and chronic liver disease. Chronic hepatitis B occurs when the immune system is unable to clear the virus, resulting in long-lasting infection that affects an estimated 262,000 people in Canada. The disease causes approximately 1.1 million deaths each year globally.¹ Many patients require lifelong antiviral therapy for viral suppression, making functional cure a critical goal in disease management. The Canadian Association for the Study of the Liver (CASL) and the Association of Medical Microbiology and Infectious Disease Canada (AMMI) updated guidelines identify functional cure as the ultimate goal of treatment.⁵

About bepirovirsen

Bepirovirsen is a triple action investigational antisense oligonucleotide (ASO), designed to recognise and orchestrate the destruction of the genetic components (i.e. mRNA and pregenomic RNA) of the hepatitis B virus that can lead to chronic disease. Bepirovirsen inhibits the replication of the viral genome in the body and suppresses the level of hepatitis B surface antigen (HBsAg) in the blood. Bepirovirsen also has innate immunostimulatory activity which may contribute to its therapeutic effect.

About B-Well Clinical trial programmes

B-Well 1 and B-Well 2 trials are global multi-centre, randomised, double-blind, placebo-controlled trials conducted in 29 countries. They assessed the efficacy, safety, pharmacokinetic profile, and the durability of functional cure in nucleos(t)ide analogue (NA)-treated participants with CHB and baseline surface antigen (HBsAg) ≤3000 IU/ml. The primary endpoint assessed the proportion of participants achieving functional cure in patients with baseline surface antigen (HBsAg) ≤3000 IU/ml. Functional cure was defined as sustained suppression (24 weeks or longer) of HBV DNA (<LLOQ) and HBsAg not detected, with or without hepatitis B surface antibodies, after a finite duration of therapy with bepirovirsen and off all HBV treatment. 

GSK licensed bepirovirsen from Ionis Pharmaceuticals and collaborated with them on its development. Bepirovirsen is currently not approved anywhere in the world.

A breakthrough therapy designation (BTD) in the United States enables greater FDA guidance on an asset's development programme.⁶ The BTD for bepirovirsen builds on the Fast Track Designation also provided by the US FDA in February 2024. A Fast Track Designation expedites the review of drugs to treat serious conditions and fill an unmet medical need.

About GSK

GSK is a global biopharma company with a purpose to unite science, technology, and talent to get ahead of disease together. Find out more at www.gsk.ca.

Cautionary statement regarding forward-looking statements

GSK cautions investors that any forward-looking statements or projections made by GSK, including those made in this announcement, are subject to risks and uncertainties that may cause actual results to differ materially from those projected. Such factors include, but are not limited to, those described in the "Risk Factors" section in GSK's Annual Report on Form 20-F for 2024, and GSK's Q4 Results for 2025.

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References

1 World Health Organization. Global Hepatitis Report 2024: Action for Access in Low- and Middle-Income Countries.
2 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)
3 Ghany MG, Buti M, Lampertico P, Lee HM; 2022 AASLD-EASL HBV-HDV Treatment Endpoints Conference Faculty. Guidance on treatment endpoints and study design for clinical trials aiming to achieve cure in chronic hepatitis B and D: Report from the 2022 AASLD-EASL HBV-HDV Treatment Endpoints Conference. Hepatology. 2023 Nov 1;78(5):1654-1673. doi: 10.1097/HEP.0000000000000431. Epub 2023 Jun 21. PMID: 37326326; PMCID: PMC12373085.
4 Maucort-Boulch, D., de Martel, C., Franceschi, S. and Plummer, M. (2018), Fraction and incidence of liver cancer attributable to hepatitis B and C viruses worldwide. Int. J. Cancer, 142: 2471-2477. Available at: https://doi.org/10.1002/ijc.31280 (last accessed March 2026)
5 The management of chronic hepatitis B: 2025 Guidelines update from the Canadian Association for the Study of the Liver and Association of Medical Microbiology and Infectious Disease Canada
6 US Food and Drug Administration. Breakthrough Therapy. Available at: https://www.fda.gov/patients/fast-track-breakthrough-therapy-accelerated-approval-priority-review/breakthrough-therapy

SOURCE GlaxoSmithKline Inc.

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