EU/3/09/648: Orphan designation for the treatment of solar urticaria

Solar urticaria is a skin disease in which exposure to ultraviolet (UV) light, or sometimes visible light, results in an acute allergic skin reaction. Patients with solar urticaria develop itching, swelling, rash and pain in the skin within minutes of exposure to light. These symptoms tend to disappear within a few hours after exposure to the light has stopped.

Solar urticaria is a long-term debilitating disease that has an impact on the patient's quality of life because it affects the ability of patients to expose themselves to sunlight.

At the time of designation, solar urticaria affected approximately 3.6 in 10,000 people in the European Union (EU). This was equivalent to a total of around 182,000 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. At the time of designation, this represented a population of 504,800,000 (Eurostat 2009).

At the time of designation, the main way to manage solar urticaria was to avoid or minimise exposure to sunlight. Common treatments included anti-allergic medicines such as antihistamines and sunscreens that reflect sunlight off the skin. In some cases, phototherapy was used. This is a technique in which the patient's skin is gradually exposed to light in a controlled manner, to improve the skin's ability to tolerate exposure to light.

The sponsor has provided sufficient information to show that afamelanotide might be of significant benefit for patients with solar urticaria because it might offer protection to a broader range of different types of light and might be given less often than existing treatments. These assumptions will need to be confirmed at the time of marketing authorisation, in order to maintain the orphan status.

Afamelanotide is a copy of the natural hormone 'melanotropin', which stimulates production of 'eumelanin' in skin cells. Eumelanin is the black-brown pigment in the skin that protects cells from the damage caused by exposure to sunlight. The way in which afamelanotide works in solar urticaria is not fully understood, but it is thought that it stimulates eumelanin production in skin cells independently of light exposure. This is expected to reduce the damage to the skin of patients with solar urticaria caused by sunlight, because the eumelanin that is produced is able to absorb UV and visible light.

Afamelanotide will be available as an implant that is placed under the skin once every two months. The implants dissolve under the skin so they do not need to be removed.

The effects of afamelanotide have been evaluated in experimental models.

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

At the time of submission, afamelanotide was not authorised anywhere in the EU for solar urticaria or designated as 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 4 June 2009 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.