EU/3/06/412: Orphan designation for the treatment of retinitis pigmentosa

Retinitis pigmentosa is a genetic (hereditary) disorder, characterised by progressive loss of sight. In retinitis pigmentosa, some cells in the retina (the light-sensitive part of the eye), called rods and cones, are progressively damaged and eventually disappear. These cells are fundamental for eyesight. Retinitis pigmentosa is chronically debilitating due to progressive loss of vision.

At the time of designation retinitis pigmentosa affected less than 3.5 in 10,000 people in the European Union (EU)*. This is equivalent to a total of less than 175,000 people, and is below the threshold for orphan designation, which is 5 people in 10,000. This is based on the information provided by the sponsor and 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 459,700,000 (Eurostat 2004).

At the time of submission of the application for orphan designation, no satisfactory methods had been authorised in the European Union for the treatment of the condition. Treatment of patients with retinitis pigmentosa primarily involved genetic counselling, and general support such as information and regular medical follow up.

4,7,10,13,16,19-Docosahexaenoic acid (DHA) is a so-called omega-three fatty acid. These acids are an integral part of the outer lipid cell membrane of all the cells in the body (the thin double layer of fatty acids that surrounds and protects cells). In the cell membrane of the rods and cones of the eye, DHA is even more abundant than in the rest of the body. It is important for the light absorption activity of these cells. There is some evidence that suggest that patients affected by retinitis pigmentosa have decreased levels of DHA. According to the sponsor, 4,7,10,13,16,19-docosahexaenoic acid will thus reduce the effects of the disease.

The effects of 4,7,10,13,16,19-docosahexaenoic acid have been evaluated in experimental models.

At the time of submission of the application for orphan designation, clinical trials in patients with retinitis pigmentosa were ongoing.

4,7,10,13,16,19-Docosahexaenoic acid was not authorised anywhere worldwide for the treatment of retinitis pigmentosa, nor designated as orphan medicinal product elsewhere for this condition, at the time of submission.

In accordance with Regulation (EC) No 141/2000 of 16 December 1999, the COMP adopted a positive opinion on 4 October 2006 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 Community) 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.