The Orphan Drugs Act gives pharmaceutical companies incentives to develop treatments for rare diseases, including a 25% tax credit for qualified clinical trials.
Other incentives include a rebate on application fees and a seven-year drug exclusivity window.
The law was passed in 1983 and resulted in the approval of more than 780 products for the treatment of more than 250 rare diseases.
About half of the approved treatments are in the field of oncology (cancer treatment).