Biogen does have assistance for you through the 'donut hole'. It is from a foundation they set up since the Medicare D rules say that assistance from a Drug company doesn't count towards the donut hole. But, the latest news on the overhaul of Insurance is that they are going to reduce the donut hole working towards eliminating it.

Once you are in catastrophic coverage your cost is 5% no matter what the drug is. Retail Avonex is about $30,000 per year.