Drug prices are complicated (kind of... But not really) . There is an exorbitant amount of R&D required to get something from hypothesis to the market.
BUT, in the US at least some of that burden is borne by the taxpayers.

Now the actual cost of making a drug once it is invented and gone through trials doesn't seem to make much of an impact on the final cost. Drug companies seem to want to charge as much as humanly possible.

Until the US has some sort of a policy change where they can influence final cost of they give tax payer dollars, then prices are going be high and get higher based on nothing but greed.