Gilead, Vir Biotechnology to Evaluate Novel Therapies for HBV

January 25, 2021 - Gilead Sciences and Vir Biotechnology recently announced that they entered into a clinical collaboration to evaluate novel therapies for chronic hepatitis B virus (HBV).

Under the collaboration, the companies will initiate a Phase 2 trial evaluating combination therapy for both treatment-experienced and treatment-naïve individuals living with HBV.

The combination therapy will include Gilead’s investigational TLR-8 agonist, selgantolimod, Vir’s investigational small interfering ribonucleic acid, VIR-2218, and a commercially-sourced PD-1 antagonist, Gilead explained. Participants in the trial may receive Gilead’s Vemildy as well. 

The primary outcome of the Phase 2 study will be the proportion of patients whose HBV is completely controllable without ongoing treatment therapy. This means that there is 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,” Anuj Gaggar, vice president of clinical research of virology at Gilead, said in the announcement.

“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,” Gaggar continued. 

Both Gilead and Vir Biotechnology will have full rights to their respective product candidates and will discuss a potential future for any combination studies based on outcomes of the Phase 2 trial. 

“We are enthusiastic about this collaboration. We believe a functional cure for the majority of patients will require a reduction of the levels of circulating viral proteins together with an immune boost to stimulate the production of new T-cells that can bring the infection under control.” said Phil Pang, MD, PhD, chief medical officer of Vir Biotechnology. 

“We believe that this collaboration with Gilead adds a novel and significant new combination to our efforts to find a cure for HBV,” Pang continued. 

HVB affects over 290 million individuals worldwide, Gilead said. It is the leading cause of liver cancer annually around the world. Specifically, more than 800,000 people die of HBV-related liver disease.

Today, there are eight approved drugs for hepatitis B in the US, two types of injectable interferons and six oral antivirals. 

The first HBV treatment, which was approved in 1997, is called Intron A. It is an immune modulator that is given by injection several times a week for six months to a year.

Notably, this drug is not used as often now as others have been developed. 

Then in 1998, FDA approved Lamivudine. Today, this drug is generally not used in the US because it is less potent than the newer drugs on the market.

In 2001, FDA approved Gilead’s Viread for the treatment of HIV infection when taken in combination with other antiretroviral agents. Viread is considered a first-line treatment with an “excellent resistance profile.”

One year later, FDA approved the company’s Hepsera, a pill that is taken once a day for at least one year. Hepsera is considered a second-line treatment option. In the same year, FDA also approved Pegasys, an immune modulator given by injection once a week from six months to one year. 

In 2005, the agency approved Bristol-Myers Squibb’s HVB treatment, Baraclude, which should be taken for one year or longer. Baraclude is considered a first-line treatment option with a positive resistance profile. 

In 2006, FDA approved HBV therapy Tyzeka to be taken for one year or longer. Similar to Hepsera, Tyzeka is considered a second-line treatment option.
Finally, in 2016, FDA approved Gilead’s Vemlidy to be administered as a 25-mg once-daily treatment for chronic hepatitis B infection in adults.