But, both of your driving factors, affected patients, and price to treat, are in turn driven by other factors such as competition, targeting symptoms, and the cost of research.

While perhaps not blockbuster, orphan drugs for rare diseases can turn quite a profit for pharmaceuticals.

http://www.forbes.com/sites/johnlamattina/2012/05/02/how-com...

http://online.wsj.com/article/SB1000142412788732392610457827...