About drugs and rare diseases in Canada

From Health Canada

About orphan drugs and rare diseases

Drugs for rare diseases are also referred to as orphan drugs in some jurisdictions. A rare disease is a life-threatening, seriously debilitating or serious and chronic condition affecting a fairly small number of patients.

There are thousands of rare diseases. Worldwide, approximately 6,000 to 8,000 rare diseases have been identified.  

More than 80% of rare diseases are genetically-based.

More than half of rare diseases start in early childhood and are:

• degenerative
• life-threatening in nature

Some approximate 1 out of 12 Canadians has a rare disease.

There is no common definition of an orphan drug or drug for the treatment of a rare disease/condition. National regulatory authorities define ‘orphan drug’ in different ways.

Many definitions include prevalence or incidence of the condition the drug is targeting. For example:

• prevalence of no more  than 5/10 000 and a life threatening, chronically debilitating condition for which no alternative treatment is available (Europe)
• a presumption of unprofitability when a disease or condition affects no more than 200,000 people in the United States  (USA)

To help communicate when we approve a drug that is considered an orphan drug by either the United States Food and Drug Administration (FDA) or the European Medicines Agency (EMA), we identify them in Health Canada’s New Drug Authorizations Highlights report.