EU/3/12/981: Orphan designation for the treatment of Leber's congenital amaurosis

Leber's congenital amaurosis is an inherited disease characterised by loss of sight at birth or soon after birth. The disease is linked to a number of genetic defects, which affect the normal development of the light-sensitive cells in the eye.

Leber's congenital amaurosis is a long-term debilitating disease due to progressive loss of vision.

At the time of designation, Leber's congenital amaurosis affected less than 1 in 10,000 people in the European Union (EU)*. This is equivalent to a total of fewer than 51,000 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).

*Disclaimer: For the purpose of the designation, the number of patients affected by the condition is estimated and assessed on the basis of data from the European Union (EU 27), Norway, Iceland and Liechtenstein. This represents a population of 506,300,000 (Eurostat 2011).

At the time of submission of the application for orphan designation, no satisfactory methods were authorised in the EU for treating Leber's congenital amaurosis. Patients with Leber's congenital amaurosis usually received genetic counselling on the risks of passing the condition on to their children, and regular medical follow up.

One form of Leber's congenital amaurosis, Leber's congenital amaurosis type 2, is caused by a defect in the gene RPE65, which is responsible for the production of the RPE65 protein. This protein has a key role in the correct functioning of the light-sensitive cells of the eye.

This medicine is made of a virus that contains normal copies of the RPE65 gene. When injected into the patient's eye, it is expected that the virus will carry the RPE65 gene into the light-sensitive cells of the eye, enabling the cells to develop normally and thereby helping to improve the patient's sight.

The type of virus used in this medicine ('adeno-associated virus') does not cause disease in humans.

The effects of adenovirus-associated viral vector serotype 2 containing the human RPE65 gene have been evaluated in experimental models.

At the time of submission of the application for orphan designation, clinical trials with this medicine in patients with Leber's congenital amaurosis were ongoing.

At the time of submission, this medicine was not authorised anywhere in the EU for Leber's congenital amaurosis. Orphan designation of the medicine had been granted in the United States of America for Leber congenital amaurosis due to RPE65 mutations.

In accordance with Regulation (EC) No 141/2000 of 16 December 1999, the COMP adopted a positive opinion on 8 February 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.