Key Takeaways:
GSK's experimental hepatitis B drug bepirovirsen achieved a functional cure in 20% of patients in two Phase 3 trials, data published in the New England Journal of Medicine showed.
"We have not had a treatment which has come to this level of cure," Dr. Seng Gee Lim of the National University Health System of Singapore, who helped lead the GSK-funded studies, said.
The trials enrolled 1,838 patients across 29 countries in Asia, Europe and the Americas. Among patients receiving bepirovirsen, 19% to 20% achieved a functional cure — defined as undetectable virus 48 weeks after stopping all treatment — compared with zero in the placebo group. In patients with lower baseline levels of a key viral protein, the cure rate rose to 26% to 28%.
Citi maintained its neutral rating on GSK, citing unresolved commercial questions around pricing, access and the intensive blood and liver monitoring required during treatment. The bank models peak annual sales of 1.6 billion pounds ($2 billion) for the drug, broadly in line with market consensus. The US Food and Drug Administration is reviewing an approval application with a decision expected by Oct. 26.
Bepirovirsen, developed with Ionis Pharmaceuticals, is an antisense oligonucleotide that works by silencing the genetic instructions the hepatitis B virus uses to replicate while also stimulating the immune system to attack infected cells. Current standard treatments, such as Gilead Sciences' Vemlidy, suppress the virus but rarely eliminate it, with fewer than 1% of patients achieving a functional cure on daily oral therapy alone.
Chronic hepatitis B affects about 300 million people worldwide and can lead to cirrhosis and liver cancer if left uncontrolled. The disease kills about 1.1 million people each year.
The functional cure rate positions bepirovirsen as a potential blockbuster for GSK, though the launch trajectory may be slower than typical given the need for screening and monitoring infrastructure. Investors will watch for the FDA's PDUFA decision on Oct. 26 and any updates on pricing and reimbursement strategy.
This article is for informational purposes only and does not constitute investment advice.
