- The Cost of Drugs for Rare Diseases Is Threatening the U.S. Health Care System Harvard Business Review by A. Gordon Smith— There are 7,000 rare diseases affecting 25 million to 30 million Americans. The average drug approved under the Orphan Drug Act of 1983 (ODA), which governs rare disease approval, costs $118,820 per year. Assuming a similar cost, if a single drug were approved under the ODA for 10 percent of rare diseases, the total would exceed $350 billion annually—more than 10 percent of the total amount that America spends on health care and much more than the health care costs attributable to either diabetes or Alzheimer's disease and other forms of dementia.