GSK turns to Sino Biopharma to push hepatitis B 'functional cure' into Chinese market

GSK has struck an exclusive partnership with Hong Kong-listed Sino Biopharmaceutical to accelerate the launch of bepirovirsen, its closely watched experimental treatment for chronic hepatitis B, in mainland China — the largest single market for the disease and one of the most strategically significant geographies for what would be a first-in-class functional cure.

Under the agreement announced on Monday, Chia Tai Tianqing Pharmaceutical Group, the hepatology-focused subsidiary of Sino Biopharma, will handle importation, distribution and promotional activities for bepirovirsen across more than 5,000 medical centres in China. GSK will retain regulatory and medical oversight. CTTQ will purchase the drug under agreed supply terms for an initial 5.5-year period. The deal capitalises on CTTQ's leading hepatology distribution franchise in China, a market in which the company has historically been one of the dominant commercial players in the treatment of liver disease.

The strategic calculus is considerable. Chronic hepatitis B affects approximately 75 million people in China, making the country home to nearly a third of the estimated 250 million chronic infections worldwide. Existing standard-of-care treatment with nucleoside analogues typically requires lifelong therapy and delivers a so-called functional cure — defined as sustained loss of the hepatitis B surface antigen and undetectable viral DNA — in only around 1 per cent of patients each year. Functional cure is associated with materially reduced risk of liver cancer and all-cause mortality, making any meaningful uplift in cure rates a clinically transformative outcome.

Bepirovirsen, an antisense oligonucleotide originally developed by Ionis Pharmaceuticals and licensed to GSK, works by degrading hepatitis B virus RNA transcripts, reducing the production of viral proteins and lifting the immune tolerance that has historically frustrated the development of curative therapies. The drug is currently under priority regulatory review by Chinese authorities, having previously been granted breakthrough therapy designation in the country. In April, the US Food and Drug Administration also accepted bepirovirsen for priority review and granted it breakthrough therapy designation, with a target action date of 26 October 2026. A separate filing in Canada was accepted under priority review at the end of April.

The regulatory submissions are supported by data from the phase 3 B-Well 1 and B-Well 2 trials, which enrolled more than 1,800 participants across 29 countries and tested bepirovirsen in nucleoside-analogue-treated patients with baseline surface antigen levels at or below 3,000 IU/ml. Both trials met their primary endpoints, with functional cure rates significantly higher when bepirovirsen was added to standard of care than with standard care alone — and with an even greater effect observed in patients with lower baseline surface antigen levels. The full data set is due to be presented at the European Association for the Study of the Liver Congress this month.

For GSK, the China deal sits at the centre of a broader strategic effort to bolster its specialty medicines portfolio under chief executive Emma Walmsley's successor, who has signalled a continued appetite for selective in-licensing and partnership transactions while steering clear of the more contested commercial battlegrounds — most notably the GLP-1 obesity market. Bepirovirsen is positioned as one of the more important late-stage assets in the group's pipeline and the centrepiece of its hepatology ambitions, which also include efimosfermin, an FGF21 analogue acquired from Boston Pharmaceuticals last year for the treatment of MASH liver disease.

GSK also said on Monday that it had launched the fifth tranche of its £2bn share buyback programme, signalling continued confidence in the group's cash generation against a backdrop of weaker top-line growth and intensifying competitive pressure on its respiratory and HIV franchises.

For Sino Biopharma, the alliance is a meaningful addition to a hepatology portfolio that already includes blockbuster hepatitis B products and a developing pipeline of liver disease assets spanning MASH, hepatitis B cure, cirrhosis and acute liver injury. Securing exclusive Chinese commercialisation of a potential first-in-class functional cure positions CTTQ to consolidate its incumbent position in a therapeutic area undergoing one of its most significant clinical inflections in decades.

The broader significance of the deal extends beyond either company. Bepirovirsen, if approved, would be the first therapy to deliver meaningful functional cure rates in adults with chronic hepatitis B — a disease whose long-term complications, including liver cirrhosis and hepatocellular carcinoma, place a substantial burden on healthcare systems in Asia, Africa and parts of Europe. The structure of the GSK-Sino Biopharma partnership, leveraging local commercial infrastructure to accelerate access in the most affected market, may also prove a template for how global pharmaceutical groups bring novel treatments for high-prevalence diseases into China without ceding ownership of the underlying asset.