Vaccitech has announced positive topline final data from its Phase Ib/IIa trial of VTP-300 in the HBV002 study (NCT04778904). 55 participants with chronic HBV who are virally suppressed with oral anti-viral therapies were given VTP-300 with or without low-dose nivolumab.

VTP-300 was observed to induce meaningful, sustained reductions of Hepatitis B surface antigen (HBsAg) in patients with chronic HBV. The Oxford, UK-based biotechnology company reported that declines were most prominent in patients with lower baseline HBsAg.

Patients receiving VTP-300 alone showed reductions of HBsAg of 0.9-1.4 log10 at five and eight months after lose dose. Patients receiving the drug in combination with low dose nivolumab showed reductions of 0.8 at 3,6, and 9 months.

Patients with lower baseline HbsAg demonstrated a greater reduction – a mean value of 1.0 log10. Two patients also developed non-detectable HbsAg at three months which persisted at eight months. T cell immune responses were observed in majority of patients.

There were no incidents of VTP-300-related Grade 3 adverse events or product-related serious adverse events following study dosing.

“The safety data and HBsAg reductions in the HBV002 study are very encouraging and we look forward to sharing the full data set, including immune responses, at the EASL conference,” said Bill Enright, CEO of Vaccitech.

“Less than 10% of people with chronic HBV reach a functional cure with current therapies. We believe VTP-300 has the potential to be a critical component of functional cure for HBV, potentially eliminating the need for chronic treatment. Our ongoing trials are exploring dosing, including an additional booster, and combination approaches with readouts expected towards the end of the year.”

Globally it is estimated that there are more than 300 million people with HBV, and prevalence is highest in East Asia and Africa. Fewer than 10% of patients with chronic HBV infection will achieve a functional cure by using existing therapies and approximately 820,000 people die each year from hepatitis B and related complications.

GSK is already on the path to its own functional cure – and eyes will be on bepirovirsen and results from its Phase III study which was initiated in early 2023.