The Orphan Drug Act was meant to incentivize the production and innovation of drugs to treat rare diseases.

But not all orphan drugs are "new" when they are approved to treat a rare disease under the law.

9Wants to Know identified a dozen drugs that were developed decades ago and were modified slightly, or not at all, before receiving 7 years market exclusivity under the Orphan Drug Act.

9Wants to Know reached out to each drug company currently selling the 12 products we focused on during our investigation. Knight Therapeutics and Arbor Pharmaceuticals did not respond to our repeated requests for comment, but the other 10 companies did.

Read their comments in full below:

Statements from pharmaceutical companies on orphan drugs