The NYT had a fascinating piece on how Questcor raised the price of its drug Acthar to $28,000 per prescription. Since it raised its price it has begun pushing the drug for a number of uses for which it may not be suited. It is able to do this because the drug was initially approved by the FDA in 1952, before restrictions on off-label marketing applied.
Until recently the drug sold for less than $2,000 per prescription. (Apparently, the manufacturing process is complicated and expensive.) At this price the drug company had little incentive to try to promote its drug for different uses. It is only the high price which provides the incentive for mis-marketing the drug.