An orphan drug is a pharmaceutical that remains commercially undeveloped owing to limited potential for profitability. The Food & Drug Administration Orphan Drug Designation program designates orphan status to drugs and biologics intended for treatment, diagnosis or prevention of rare diseases or conditions. The FDA defines a rare disease or condition as those affecting less than 200,000 people in the U.S. — or affecting more than 200,000 provided that the drug is not expected to recover the costs of developing and marketing.