EU/3/19/2137: Orphan designation for the treatment of severe combined immunodeficiency due to FOXN1 deficiency

Severe combined immunodeficiency due to FOXN1 deficiency is an inherited disorder where the patient is unable to fight infections due to the lack of a type of white blood cells called T cells. The disorder is caused by mutations (changes) in the gene for FOXN1. FOXN1 is involved in the formation of the thymus gland (a gland below the breastbone that helps T cells to develop properly).

Severe combined immunodeficiency due to FOXN1 deficiency is a long-term debilitating and life-threatening condition due to recurrent and severe infections.

At the time of designation, severe combined immunodeficiency due to FOXN1 deficiency affected less than 0.01 in 10,000 people in the European Union (EU). This was equivalent to a total of fewer than 500 people*, and is below the ceiling for orphan designation, which is 5 people in 10,000. This is based on the information provided by the sponsor and the knowledge of the Committee for Orphan Medicinal Products (COMP).

At the time of application for orphan designation, there was no satisfactory treatment for severe combined immunodeficiency due to FOXN1 deficiency authorised in the EU. Patients were managed with supportive care. Some patients had received experimental blood stem cell or bone marrow transplants.

The medicine comprises slices of tissue from a donor’s thymus gland. The donor tissue is processed in a laboratory so that it is compatible with the patient’s body and is then inserted into the patient’s body by surgery. This is expected to help patients produce T cells and fight infections.

The effects of the medicine have been evaluated in experimental models.

At the time of submission of the application for orphan designation, clinical trials with the medicine in patients with severe combined immunodeficiency due to FOXN1 deficiency were ongoing.

At the time of submission, the medicine was not authorised anywhere in the EU for severe combined immunodeficiency due to FOXN1 deficiency or designated as an orphan medicinal product elsewhere for this condition.

In accordance with Regulation (EC) No 141/2000 of 16 December 1999, the COMP adopted a positive opinion on 24 January 2019 recommending the granting of this designation.

• the seriousness of the condition;
• the existence of alternative methods of diagnosis, prevention or treatment;
• either the rarity of the condition (affecting not more than 5 in 10,000 people in the EU) or insufficient returns on investment.

Designated orphan medicinal products are products that are still under investigation and are considered for orphan designation on the basis of potential activity. An orphan designation is not a marketing authorisation. As a consequence, demonstration of quality, safety and efficacy is necessary before a product can be granted a marketing authorisation.