I'm late to the party on this one, but (as I've probably posted here before) the root cause of high drug prices in the US comes back to the US's broken political system.

Pharma companies charge more in the US because they can - because there are no strong reasons not to, and no mechanisms to prevent them doing so. And it's possible for big pharma to maintain this status quo because the political system in the US, with big money from lots of different companies and sectors funding politicians directly and indirectly, allows it.

Short of a conviction-driven leader (in the vein of Bernie Sanders, [or, surprisingly, Trump! - tough rhetoric on drug pricing was about the only thing I agreed with him on, although little was ultimately delivered]) or major changes to political funding (e.g. tight limits on funding of and spending by politicians, as exists in many other countries) nothing will change.