Dear @mantana,
We have to be careful about press releases like these that purport to demonstrate that a “promising” reduction of HBsAg is due to an adaptive response specific for HBV antigens. Numerous other vaccines which done the same have failed to alter HBsAg levels. This is due to the genetic / immunological heterogenity in viral antigens which develops with chronic infection.
The difference with VRON-0200 is that is contains adenovirus, which is directed towards the liver and, along with the antigen encoding DNA it contains, stimulates innate immunity to transiently suppress cccDNA activity. As such, HBsAg from integrated HBV DNA is not being targeted. This is the same limitation we have seen with siRNA and antisense.
The HBsAg response to VRON-0200 is highly variable and weaker than we have seen with siRNA. I would not describe this as “encouraging”.