Not only are there orphan drugs, there are orphan diseases, one of which is MS. One of the major drugs used to control this is Avonex. Check out
the cost of a monthly supply, and note that a monthly supply consists of exactly four doses. About the only way anybody but the 1% can afford it is the fact that if you're using it you're automatically eligible for Medicare, SSI and whatever assistance your state offers. And, I suspect that if that weren't the case, the price would drop dramatically because without the subsidies there wouldn't be any market for it.