GSK’s bepirovirsen NDA accepted by Japan MHLW for chronic hepatitis B treatment. Phase III B-Well trials show significant functional cure rates vs. standard care in CHB patients. SENKU-designated ASO targets unmet need.
Written By: Samiksha Jadhav, BPharm
Reviewed By: Pharmacally Editorial Team
GSK plc announced that Japan’s Ministry of Health, Labour and Welfare (MHLW) has accepted a new drug application (NDA) for bepirovirsen, an investigational antisense oligonucleotide (ASO), targeting adults with chronic hepatitis B (CHB).
This follows positive Phase III results and builds on the drug’s SENKU designation granted in August 2024, which accelerates review for innovative therapies addressing high unmet needs.
CHB affects over 250 million people worldwide, including nearly 1 million in Japan, driving about 1.1 million global deaths annually roughly 4,000 in Japan alone. Current treatments like nucleos(t)ide analogues (NAs) demand lifelong use with functional cure rates below 1%. Functional cure defined as undetectable hepatitis B virus DNA and HBsAg for at least 24 weeks post-treatment, controlled by the immune system slashes risks of liver complications, including the 56% of global liver cancer cases linked to CHB.
The NDA based on the B-Well 1 (NCT05630807) and B-Well 2 (NCT05630820) Phase III trials, global multicentre, randomized, double-blind, placebo-controlled studies across 29 countries. These evaluated efficacy, safety, pharmacokinetics, and cure durability in non-cirrhotic, NA-treated patients with baseline HBsAg ≤3000 IU/ml.
Bepirovirsen plus standard-of-care achieved statistically significant, clinically meaningful functional cure rates versus standard-of-care alone across primary and ranked secondary endpoints especially in those with baseline HBsAg ≤1000 IU/ml.
Safety aligned with prior studies, showing good tolerability. Full data are slated for a 2026 congress presentation and peer-reviewed publication.
Bepirovirsen acts via triple mechanism: destroying viral mRNA and pregenomic RNA, inhibiting genome replication, reducing blood HBsAg, and boosting immune control for potential durable responses.
Licensed from Ionis Pharmaceuticals, it’s eyed as a backbone for broader sequential regimens. Global nods include US FDA Fast Track and China Breakthrough Therapy designations. Bepirovirsen remains unapproved worldwide.
This filing signals progress toward transforming CHB management, potentially offering the first functional cure option beyond suppression therapies.
Reference
Bepirovirsen accepted for regulatory review in Japan as a potential first-in-class treatment for chronic hepatitis B, 26 February 2026, Bepirovirsen accepted for regulatory review in Japan as a potential first-in-class treatment for chronic hepatitis B | GSK
Study of Bepirovirsen in Nucleos(t)Ide Analogue-treated Participants with Chronic Hepatitis B (B-Well 1) (B-Well 1), ClinicalTrials.gov ID NCT05630807, https://clinicaltrials.gov/study/NCT05630807
Study of Bepirovirsen in Nucleos(t)Ide Analogue-treated Participants with Chronic Hepatitis B (B-Well 2) (B-Well 2), ClinicalTrials.gov ID NCT05630820, https://clinicaltrials.gov/study/NCT05630820
About Writer
Samiksha Vikram Jadhav, B.Pharm
She is a pharmacy graduate with a keen interest in clinical research, pharmacovigilance, and medical writing, with a growing focus on publication and scientific content development. In her words, she is passionate about translating complex medical data into clear, evidence-based communication.