GSK and Ionis Pharmaceuticals’ genetic medicine, bepirovirsen, has demonstrated its functional curative potential in chronic hepatitis B (CHB) – a development that analysts say could see the drug become a potential disruptor in the condition.
According to pooled data from the Phase III B-Well 1 (NCT05630807) and B-Well 2 (NCT05630820) studies, 19% of patients who received bepirovirsen for six months obtained a functional cure response, meaning that the virus reached an undetectable level in an individual’s blood for at least six months after they stopped treatment. Nobody in the placebo groups of either study experienced this outcome.
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The functional cure rate was even higher amongst patients with low levels of a specific viral protein called hepatitis B surface antigen (HBsAg), with 26% of participants achieving this six-month post-treatment. Researchers currently estimate that around 45% of patients diagnosed with CHB fall into this category.
Meanwhile, bepirovirsen demonstrated an “acceptable” safety and tolerability profile, with the most common adverse events (AEs) being redness around the injection site, localised pain and temporary liver enzyme elevations.
Currently, the SoC treatment for CHB is lifelong treatment with antiviral nucleotide analogue (NA) therapies, which are associated with functional cure rates of around 1%.
According to Stephanie Kurdach, infectious disease analyst at GlobalData, the results of the B-Well programme will likely have a “transformative” impact on the CHB market, while analysts at Jefferies note that the B-Well data is “likely to meaningfully shift the hepatitis B treatment paradigm, particularly for patients who are already on therapy”.
Positive analyst sentiments will be welcomed by bepirovirsen licensee, GSK and the drug’s original developer, Ionis Pharmaceuticals, who are currently awaiting a verdict from US, European and Japanese regulators on the drug. GSK expects first decisions on bepirovirsen in CHB to be made in Q3 2026.
Analysts praise bepirovirsen’s paradigm-shifting potential
While Kurdach touts the data from the B-Well trials as “truly revolutionary” and that the drug will “undoubtedly transform the CHB market” she notes that patients with cirrhosis or other complications/co-morbidities were excluded from these studies.
This means it is unclear if the drug is effective in a large subset of patients living with CHB, resulting in a continued area of significant unmet need for ineligible patients.
William Blair analysts anticipate “broad uptake” of bepirovirsen in hepatitis B.
Attention turns to functional cures in hepatitis B
Bepirovirsen makes moves toward the commercial market amid the backdrop of shifting industry attention in CHB, with companies increasingly diverting focus away from daily management of the condition towards treatments that can elicit a functional cure response.
This includes AusperBio, which is currently evaluating its bepirovirsen rival and fellow antisense oligonucleotide (ASO), AHB-137, in a Phase III trial.
GlobalData currently forecasts that functional cure drugs will account for over 65% of the chronic hepatitis B market sales by 2034.
