Orphan medicines are medicinal products that are intended to treat diseases which are so uncommon that it would be difficult to secure funding for drug development under usual marketing conditions. Owing to this, orphan medicines in Great Britain are products which have already been granted an EU Marketing Authorisation (MA) and are subject to a GB orphan Manufacturing Authorisation Application (MAA) made under regulation 50G of the Human Medicines Regulation 2012.
All medicines which are granted an orphan MA by the Medicines and Healthcare products Regulatory Agency (MHRA) will be listed on the Orphan Register. The Orphan Register is a list of authorised orphan medicinal products registered by the MHRA. It includes EU MAs which are converted into GB MAs in accordance with paragraph 6(7) of Schedule 33A of the Human Medicines Regulation 2012.
As an orphan medicine is given its orphan status and added to the Orphan Register, the medicinal product will be given up to 10 years of market exclusivity from similar products in the Orphan Register.
For a medicinal product to be valid for orphan registration and an orphan MAA, it must meet strict criteria. It must be intended for treatment, prevention, or diagnosis of a life-threatening or chronically debilitating disease. The prevalence of the disease in GB must be equal to or less than 5 cases in every 10.000 people (or it must be unlikely that the marketing of the medicine would produce sufficient profit to cover the development costs). Lastly, there must be no satisfactory method of diagnosis, prevention, or treatment of the condition already licenced. If valid medicinal treatment is already licensed in GB, then the potential orphan medicine must be of significant benefit to those affected by the condition.
Examples of orphan drugs licensed for GB use are Fintepla (fenfluramine) which is used to treat seizures associated with Dravet syndrome. Dravet syndrome is a rare but severe form of epilepsy. Another example would be Imnovid (pomalidomide) which is used to treat patients suffering from multiple myeloma (bone marrow cancer) who have not responded to 2 previous treatment attempts.
For more information, please refer the links below:
Orphan medicinal products
https://www.gov.uk/guidance/orphan-medicinal-products-in-great-britain
Orphan registered medicinal products
https://www.gov.uk/government/publications/orphan-registered-medicinal-products