I suspect this announcement could qualify as a "damage-control" PR too, if IDIX advises "licensing talks" are now pending given the latest news on the 800 mg dose. "Dear Shareholder....Since there were some GI side effects observed at 800mg, NVS feel it would be prudent to wait and analyze further Phase II data before opting in"....
Given the recent side effects news, I don't know why NVS would feel compelled to opt-in at this juncture until all data from Phase II was analyzed thoroughly. Marketing their Hep B drug in China could be very lucrative revenue wise. Smart move on behalf of NVS and IDIX. I wouldn't complain.