What is a rare disease?
A “rare disease” (also called an "orphan disease") is an illness that affects a small percentage of the population, thereby limiting scientific research, clinical expertise and patient access to effective treatment options.
In the Unites States, a rare disease is defined as one that affects fewer than 200,000 Americans at any given time.
What is an orphan drug?
An "orphan drug" is a medication or other medicinal product used to treat a rare disease.
They are called “orphan drugs” because due to their limited market, they are rarely adopted by pharmaceutical companies.