GSK Hepatitis B Treatment Delivers Positive Phase III Trial Results

GSK has announced headline data from two pivotal phase III trials for bepirovirsen, a chronic hepatitis B treatment that could transform care for a disease affecting approximately 250 million people worldwide. The pharmaceutical company previously indicated that the drug could generate peak year sales exceeding £2 billion following approval and commercial launch, which is anticipated during 2026.

Bepirovirsen represents one of 15 major product launches that GSK expects to contribute towards its strategic sales growth target of more than £40 billion by 2031. The positive trial results demonstrate a statistically significant and clinically meaningful functional cure rate in patients receiving bepirovirsen combined with standard of care treatment, compared with standard care alone. Functional cure occurs when the virus becomes undetectable in the blood and the immune system can subsequently control the infection.

The announcement arrives following Luke Miels’ formal appointment as chief executive officer last week. Miels, aged 51 and formerly chief commercial officer, has replaced Dame Emma Walmsley and brings a particular commercial emphasis to GSK as the company seeks to launch new drugs after a period focused on pipeline refreshment. Successful product launches would help address investor concerns regarding GSK’s capacity to navigate the patent expiry of its key HIV drug dolutegravir in 2028 and achieve its 2031 headline target.

Chronic hepatitis B represents the primary cause of more than half of global liver cancer cases and accounts for more than one million deaths annually. The disease carries significant therapeutic challenges and represents a substantial unmet medical need. In 2024, the United States Food and Drug Administration granted an expedited review process for bepirovirsen due to its potential to address this serious public health concern.

GSK licensed bepirovirsen from Ionis Pharmaceuticals in 2019 and subsequently agreed in 2023 to pay up to $1 billion for exclusive rights to further develop and commercialise a complementary hepatitis B therapy owned by Johnson & Johnson. This strategic acquisition supports the expansion of bepirovirsen and strengthens GSK’s position within the hepatitis B treatment market.

Equity analysts at Jefferies stated that the positive headline trial results should substantially reduce risk perception around this opportunity, forecasting peak sales of approximately £1.1 billion. The investment research firm noted that management’s characterisation of the result as clinically meaningful aligns with previous guidance suggesting a functional cure rate threshold of 15 per cent or higher. GSK shares closed up 2 pence, representing a 0.1 per cent increase, at £19.01 pence on Wednesday, extending gains over the preceding 12 months to nearly 40 per cent and valuing the company at £77.4 billion.