GSK's Bepirovirsen: A Potential Breakthrough in Chronic Hepatitis B Treatment

GSK (GSK.L) has announced positive outcomes from two pivotal Phase 3 trials, B-Well 1 and B-Well 2, evaluating its experimental drug, bepirovirsen, for chronic hepatitis B (CHB). The trials, which involved over 1,800 patients across 29 countries, demonstrated a statistically significant and clinically meaningful functional cure rate compared to the current standard of care, nucleos(t)ide analogues. A functional cure is defined as the sustained loss of hepatitis B surface antigen (HBsAg) and undetectable hepatitis B virus (HBV) DNA for at least 24 weeks following treatment. Current therapies typically achieve functional cure rates of only 1% to 4%.

GSK Release Bepirovirsen Update January 7, 2026BioSpacePharmaphorumFierce BiotechGSK Says New Hepatitis B Treatment Works But Won't Reveal How Many Patients It Cured

Chronic hepatitis B is a significant global health challenge, affecting more than 250 million individuals and leading to approximately 1.1 million deaths annually. It is also responsible for 56% of liver cancer cases worldwide. The disease persists when the immune system fails to eliminate the virus, necessitating lifelong antiviral therapy for many patients. Bepirovirsen, an antisense oligonucleotide licensed from Ionis Pharmaceuticals in 2019, aims to block viral replication, reduce HBsAg levels, and stimulate the immune response.

GSK Release Bepirovirsen Update January 7, 2026BioSpaceReutersPharmaphorumGSK Says New Hepatitis B Treatment Works But Won't Reveal How Many Patients It Cured

The B-Well trials met their primary endpoints, showing that bepirovirsen, when combined with standard care, achieved higher functional cure rates than standard care alone. Notably, the results were particularly pronounced in patients with baseline HBsAg levels below 1,000 IU/ml. GSK has not yet disclosed the exact cure rates, which has raised questions about the magnitude of the treatment's efficacy. Analysts suggest that a rate of 15% to 20% would be significant for patients.

GSK Release Bepirovirsen Update January 7, 2026

GSK's Chief Scientific Officer, Tony Wood, stated, “Bepirovirsen has the potential to transform treatment goals for people living with CHB by achieving significant functional cure rates—a first for the disease.” The company plans to submit regulatory filings globally starting in Q1 2026, aiming for bepirovirsen to become the first finite, six-month therapeutic option for CHB.

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Despite the promising results, some experts have expressed caution. Concerns include the lack of detailed efficacy data and the trial's patient selection criteria, which may limit the generalizability of the findings. Critics argue that the focus on patients with lower HBsAg levels could skew the perceived effectiveness of bepirovirsen, potentially narrowing its addressable market. Additionally, the current healthcare infrastructure may pose challenges in monitoring and managing treatment.

GSK Says New Hepatitis B Treatment Works But Won't Reveal How Many Patients It Cured

While GSK's announcement highlights the potential of bepirovirsen, it does not provide specific figures on the functional cure rates achieved in the trials. This omission has led to speculation about the treatment's actual effectiveness. Furthermore, the market for hepatitis B treatments is competitive, with other therapies showing higher functional cure rates in similar patient populations.

GSK Release Bepirovirsen Update January 7, 2026

GSK is expected to present full data from the B-Well trials at an upcoming scientific congress, which will clarify the treatment's efficacy and safety profile. The outcomes will be critical in determining whether bepirovirsen can establish itself as a leading therapy for chronic hepatitis B or if it will face challenges from emerging competitors.

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• “Bepirovirsen has the potential to transform treatment goals for people living with CHB by achieving significant functional cure rates—a first for the disease,” — Tony Wood, Chief Scientific Officer, GSK

Fierce Biotech

• “Today’s positive results are made possible by the strategic collaboration between Ionis and GSK, and demonstrate that bepirovirsen has the potential to bring hope to the millions of people living with CHB.” — Brett P. Monia, Ph.D., CEO, Ionis

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