Orphan Drug Status in the USA has a threshold value that is as follows:
The disease or condition for which the drug is intended affects fewer than XXXXXXXX people in the United States or, if the drug is a vaccine, diagnostic drug, or preventive drug, the persons to whom the drug will be administered in the United States are fewer than XXXXXXXX per year.
Above this threshold the Drug may still be classed as Orphan providing that certain criteria are met.
What is the threshold value above?