A regulatory body looks at how much something "should" cost based on its history of reimbursement and the cost of its inputs and then sets a cap of say, cost + 20%.
The problem is having an independent body that is free of influence of health insurance companies and hospitals, both of which have perverse incentives to continue profiteering.
The US is too big, too diverse, too whatever else, blablabla for things that work perfectly anywhere else in the world. Nothing can be learned from other countries unless it makes capitalists richer.
Medicines are more complicated because the manufacturer will probably have patents that grant them a manufacturing monopoly, meaning they can always set the price to whatever they want anyway. Not to mention that a multinational can afford to make less in some countries as long as on average they make enough to continue doing research. If Germany somehow sets a price that is egregiously low, the manufacturer can simply sell their medicine elsewhere instead.