As an added note, Biogen has a patient assistance program with no income limit. If you don't have insurance you get help and even if you do have insurance you pay nothing more than $10 per month.
So the counter side to that is basically Biogen is bilking the hell out of the insurance companies. While it is noble of them not to screw over poor MS patients, they're screwing over the rest of the healthcare system instead.
It took 'em a big pile of money to prove a cheap chemical is suitable treatment for a major disease. Who, by you, should make it worth their while to do so? and to do such things more than once?
I'd say that's a pretty good deal.