GSK has netted the first approval globally for its chronic hepatitis B therapy, bepirovirsen, from Japan’s Ministry of Health, Labour and Welfare (MHLW) – marking the first entry of a functional cure to the indication’s market.
The antisense oligonucleotide (ASO)-based medicine, which GSK will market as Hibsago, is now indicated for use in Japanese adults with hepatitis B who meet pre-defined viral markers. To be eligible, patients must have received at least six months of treatment with a prior standard of care (SoC), viral suppressing nucleos(t)ide analogue (NA). Researchers estimate that NAs trigger a functional cure rate of around 1%.
Japan’s MHLW gave Hibsago its regulatory blessing based on the positive results of the Phase III B-Well programme, which revealed that 19% of patients treated with the drug for six months achieved a functional cure response versus zero in the placebo group. Previously, analysts touted the “transformative” impact of this data on the chronic hepatitis B market and the treatment paradigm for patients.
GSK and the drug’s original developer, Ionis Pharmaceuticals, will welcome Hibsago’s approval, as they also await a verdict on the drug from US and European regulators – potentially further expanding its reach across the global market. The pair expect the US Food and Drug Administration (FDA) to make a call on Hibsago in October 2026.
In a recent report by GlobalData, parent company of Pharmaceutical Technology, analysts predicted that the “highly anticipated” debut of functional cures will drive future growth in the chronic hepatitis B market. Currently, GlobalData predicts that Hibsago will approach blockbuster status in 2034 by pulling in global sales of $926m – potentially commanding a notable chunk of the chronic hepatitis B market expected to hit a value of $3.2bn in 2034.
The evolution of the hepatitis B treatment landscape
Currently, the World Health Organization (WHO) estimates that there are around 240 million people living with chronic hepatitis B globally – of which one million reside in Japan. The viral infection, which is primarily spread by bodily fluids, is commonly associated with inflammation and damage to a patient’s liver, which can result in serious complications or death if left untreated.
While NAs have been the SoC for the treatment of chronic hepatitis B for decades, some drugmakers are now exploring the potential of other mechanisms of action that could prove effective in the disease.
This includes notable infectious disease player, Gilead Sciences, which is progressing its therapy, selgantolimod through late-stage trials. Like Hibsago, the drug acts as an agonist of the toll like receptor 8 (TLR8).
According to GlobalData, three other pipeline products could launch on the chronic hepatitis B market before 2034 – including GSK’s small interfering RNA (siRNA), daplusiran and tomligisiran, Arbutus Biopharma’s hepatitis B virus (HBV) surface antigen inhibitor, imdusiran, and Aligos Therapeutics’ capsid protein inhibitor, ALG-000184.
