Gilead Sciences and Vir Biotechnology have partnered to evaluate novel therapeutic combination strategies aimed at developing a ‘functional cure’ for chronic hepatitis B virus (HBV).

As part of the clinical collaboration, the companies are expecting to launch a Phase II trial evaluating combination therapies for both treatment-experienced and treatment-naïve people living with HBV.

This study will evaluate a number of combinations of Gilead’s investigational TLR-8 agonist selgantolimod, Vir’s small interfering ribonucleic acid (siRNA) candidate VIR-2218 and a marketed PD-1 antagonist.

Study participants who have previously received treatment for HBV may also be given Gilead’s Vemlidy (tenofovir alafenamide fumarate, TAF).

As part of the agreement, both companies will retain full rights to their individual product candidates and will discuss the ‘potential path forward’ for future studies based on the outcome of the Phase II study.

The primary outcome of this first combination study will be the number of patients achieving a functional cure – defined here as an off-therapy loss of hepatitis B surface antigen (HBsAg) and HBV DNA from the serum.

“Gilead has a two-decade commitment to people with hepatitis B and we have worked tirelessly to bring new treatments forward with the goal of helping to improve their lives,” said Anuj Gaggar, vice president, Clinical Research, Virology at Gilead Sciences.

“We believe that selgantolimod and VIR-2218 have the potential to be best-in-class therapeutics and could provide a compelling new combination approach to a functional cure for HBV,” he added.