Well those 20 years are where they make all the money - there is a lot of reason to think that they would just double prices if you were to cut that period in half. Given that Humira has made life livable for millions of people with RA, Crohn's and a bunch of other really terrible problems I'd argue it was worth every cent of the $200 billion in sales (we probably spent the same amount on annual UN fees and diplomats over the same time period). I think something should be done about this patent gamesmanship but I find it hard to see them as evil when they have a patient assistance program that covers the overwhelming majority of the population.

Look to be fair, a majority of a drug's time under patent will be during development, when they can't make any revenue. It's even been argued that the high cost of new medication is (partially) because they only have a short period of time to actually sell it while under patent (it takes roughly 8-15 years to bring a drug to market).

I personally believe that while these abuses of the system absolutely should be accounted for, reducing the period of patent to 10 years won't help anything.