There is another consequence: the FDA may allow you to classify the compound as an orphan drug based on a much smaller market than the entire disease pool. This

There is another consequence: the FDA may allow you to classify the compound as an orphan drug based on a much smaller market than the entire disease pool. This greatly reduces the burden of getting a drug approved because orphan drugs have too few patients to justify the expense of the usual approval process and the FDA gives them special treatment for humanitarian reasons and to promote a wider field of research than just the drugs with large profit potential.