GSK licenses hepatitis B drug from J&J in $1bn deal

GSK has set its sights on dominance of the market for hepatitis B virus (HBV) therapeutics, licensing an antisense oligonucleotide drug from Arrowhead Pharma and Johnson & Johnson that had been considered a rival to its in-house candidate bepirovirsen.

The deal sees rights to JNJ-3989 (also known as ARO-HBV) transfer from J&J’s Janssen pharmaceuticals unit to GSK in return for around $1 billion in upfront and potential milestone-based payments.

Under the terms, Janssen – which licensed rights to JNJ-3989 from Arrowhead in 2018 - will continue to be responsible for ongoing trials of JNJ-3989 at its expense and GSK will take on all future development and commercialisation activities.

GSK said the deal will expand its HBV portfolio with a drug that could be used in tandem with bepirovirsen, which last year became the only single agent in late-stage development to achieve a ‘functional cure’ response in HBV patients.

In the 457-patient B-Clear study, bepirovirsen at a dose of 300 mg per week over 24 weeks resulted in sustained hepatitis B surface antigen (HBsAg) and HBV DNA loss to below the limits of detection in 9% to 10% of participants with chronic HBV infection.

A functional cure is said to have been achieved if HBsAg is cleared from the blood and remains undetectable after stopping all treatment. With JNJ-3989, GSK hopes to develop a sequential regimen with bepirovirsen that will improve the functional cure rate.

HBV affects almost 300 million people worldwide, according to GSK, and while nucleoside/nucleotide analogue (NA) drugs to treat it are available – such as Gilead’s polymerase inhibitor Viread (tenofovir) – they are only able to achieve a functional cure in 3% to 7% of patients.

GSK said the deal will also build its presence in the antisense category and extend an earlier $1 billion-plus alliance with Arrowhead focused on an antisense therapy for chronic liver diseases, including non-alcoholic steatohepatitis (NASH).

Analysts at William Blair have suggested that the market for an HBV cure could be around the same size as for hepatitis C virus (HCV), which peaked at around $10 billion a year and was dominated by Gilead drugs but was a short-lived bonanza, with sales falling sharply as the pool of eligible patients reduced.

JNJ-3989 is in early-stage clinical development but will progress quickly into phase 2 as part of a sequential regimen with bepirovirsen beginning in 2024, said GSK.

Bepirovirsen was moved into phase 3 testing as a monotherapy earlier this year, and is also being tested in combination with pegylated interferon in a phase 2 trial. GSK had also been studying the drug in a phase 2 trial alongside HBV immunotherapy GSK3528869A, but that no longer appears in its pipeline listing.