…I wouldn't be shocked if Roche tries adding a third drug with a new mechanism in the not too distant future (I believe they have their own internal Helicase program). It seems now there are a number of qD candidates in the <200-300mg range so co-formulation may be a bit more practical.
I agree, and I would add that a purine nuke such as IDX184 can be considered a different MoA from RG7128, which is a pyrimidine nuke. Note that PSI-7977 is also a pyrimidine nuke, so we can presumably rule out a cocktail that contains both RG7128 and PSI-7977.