Sorry, but isn't it just outright fraud to charge > 400$ for a medication, which has a "retail price" of a few $?
It'd only be fraud if the government was paying for it.
[Edit]Some hate against my comment. For those that fail to understand...
It isn't fraud if you go to a gas station that is charging $0.10 more a gallon, and fill up there. It's fraud if you pay for that gas, and its water. The insurance is still buying the same drug, they have just chosen to negotiate a price that is higher with one hospital than another. They have their own reasons for deciding that price.
Likewise it would be fraud if the government was paying for it, since they have set rates. To achieve a higher payment would require billing them for some other product.
Scenario 1: A gas station with bags of ice sells out their inventory of ice and beer to a local fraternity, so they can keep their beer cold while they're on the road.. Then a diabetic guy comes in, looking for a way to keep his insulin supply cold. Too bad for him, the ice is gone.
Scenario 2: That gas station jacks up the price to $100/bag during the evacuation. The frat guys aren't willing to pay that much for cold beer, so they grumble and just buy some bottled water instead, since that doesn't need to be cold to drink it. The diabetic guy comes in looking for ice. He too grumbles at having to pay $100, but his insulin supply will now stay fresh.
This is a little contrived, but I think it illustrates that even in extreme cases, the system of pricing in a free market allows each participant in the market to communicate his priorities and his ability to substitute other goods. My example shows how the frat guys want beer, but not enough to pay that huge amount -- which leaves the way open for the diabetic to show that the ice is really, really important to him.
The same effect explains the semi-mythical $75,000 toilets in government procurements; yes, the government may often over pay, even somewhat obscenely, but typically those sorts of stories are because of accounting doing things like dividing the bill evenly according to every item. Yes, you got a $75,000 toilet, but you got a $75,000 MRI machine on the "same bill".
Health care can't be forced down by price (at least, life saving health care), so you either have to stop providing care to those that need it but can't pay, or pass along the costs to others.
I'm not saying those approaches don't have flow on effects, because they do but they can be used to lower costs. Don't assume price cannot be controlled by governments or industry, because it can be, and is.
Medical school is entirely too expensive, which limits doctors going into general or emergency care, which causes further strain on the system.