The entire drug research sphere outside of the US is miniscule. Unless you can sell the drug in the US there's very little point to investing in the large scale research needed to truly determine efficacy. Yeah there's some minimal state sponsored stuff outside of the US. BUt it's like comparing Little League to the MLB.
Ok, I think your list, and the fact that HALF are in 1 Country VS the entire rest of the world qualifies my statement. As well Roche, ASZ, and GSK do the bulk of their research in the US.
On top of that the largest outside of the US is China and there is very little trust of data coming from there in the Western World.
Maybe from the fact that half of all pharmaceutical revenues come from the US (and likely a much higher share of the profits). Single-payer systems are more cost-effective but definitely provide less revenue to pharmaceutical companies.
