Orphan Drugs

Orphan drugs are medicines with a special designation because they treat rare or orphan diseases. The designation encourages drug makers to develop these medicines and get them approved.

Drug companies would normally lose money trying to create a new drug for orphan diseases because of how rare they are. But in 1983, the United States passed the Orphan Drug Act. The incentives from it encourage drug companies to find new treatments and limit any money lost doing so.

Those incentives include:

• Tax credits
• Waivers for new drug fees
• Exclusive rights to the drug for up to seven years (no other company can get an approval for it during this period)

Drug companies can bring a new orphan drug to the market in one of two ways:

• Create a whole new drug. This means going through the process of researching, creating and testing a new drug. The average time it takes to do this is a decade. It can cost hundreds of millions or even billions of dollars. This is the most common route.
• Find new uses for existing drugs. This means getting approval for an existing drug to treat an orphan disease (in adults, children or both). The orphan designation only applies to the orphan diseases it treats. This still takes years of research and testing, and costs millions of dollars.

After the U.S. passed the Orphan Drug Act, several other countries took similar actions. Today, Japan, Australia and the European Union all now have their own orphan drug laws.

What diseases do orphan drugs treat?

More than 6.5 million people in the U.S. could receive orphan drugs as treatments. A few examples of the rare and orphan diseases that orphan drugs treat include:

• Autoimmune and inflammatory diseases, especially those in younger people, such as juvenile rheumatoid arthritis
• Digestive system inflammatory diseases, like Crohn’s disease and ulcerative colitis
• Endocrine and hormone conditions, like Cushing’s syndrome or growth hormone insensitivity syndrome
• Genetic blood disorders, such as sickle cell disease, von Willebrand disease or different types of hemophilia
• Infectious diseases, like anthrax, Ebola virus disease, malaria or Clostridioides difficile
• Nervous system conditions, like amyotrophic lateral sclerosis, Behçet’s disease or multiple sclerosis
• Rare forms of cancer (either because the cancer is rare, it’s in a rare place or it’s rare for it to happen at a certain age)
• Rare forms of malnutrition, such as scurvy
• Seizure disorders, like Lennox-Gastaut syndrome
• Treatments for uncommon types of venomous bites, like from snakes or spiders

What are some examples of orphan drugs?

There are hundreds of orphan drugs. From 1990 to 2022, the U.S. Food and Drug Administration (FDA) granted the orphan drug designation to 491 medicines. For most of those drugs, a rare disease was the first reason they got approval.

Some examples of orphan drugs include:

• Antiseizure medications, like diazepam or fosphenytoin for seizures that won’t stop (status epilepticus) or seizure disorders
• Antivirals, like acyclovir for viral outbreaks, like with herpes simplex virus
• Drugs for childhood circulatory conditions, such as pulmonary arterial hypertension
• Drugs for rare infectious diseases, like malaria, anthrax or AIDS
• Drugs that treat genetic metabolic diseases, such as familial hypercholesterolemia
• Hydroxycobalamin for cyanide poisoning
• Monoclonal antibodies, like bevacizumab, infliximab or pembrolizumab, for cancers of different types or that start in different places
• Stimulants like modafinil for narcolepsy