EU/3/10/756: Orphan designation for the prevention of scarring post glaucoma filtration surgery

Glaucoma is a disease in which the pressure in the eye rises because the fluid inside the eye cannot drain away. The pressure affects the optic nerve (the nerve that sends signals from the eye to the brain) and can cause loss of vision. Glaucoma can be treated using 'filtration surgery', when the surgeon makes a small hole in the sclera (the white of the eye), so that the fluid that has built up in the eye can drain away. Scarring can occur after surgery if too much collagen (a type of protein) is laid down in the channel during healing. This can seal the channel up and cause the pressure inside the eye to build up again.

Scarring post glaucoma filtration surgery is a serious and long-term debilitating condition because it may lead to loss of vision.

At the time of designation, the number of patients at risk of scarring post glaucoma filtration surgery was estimated to be less than 3 in 10,000 people in the European Union (EU)*. This is equivalent to a total of fewer than 152,000 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 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 506,500,000 (Eurostat 2010).

At the time of designation, no satisfactory methods were authorised in the EU for the prevention of scarring post glaucoma filtration surgery. Medicines that stop the growth of cells, such as 5-fluorouracil and mitomycin C (which are also used to treat cancer), were applied to the eye during surgery to slow down the formation of scar tissue and prevent the channel sealing up.

Tranilast is expected to work by blocking the release of 'transforming growth factor beta' (TGF-β), a protein involved in wound healing that can cause excessive collagen production and scarring. The reduction of TGF-β levels is expected to help the wound in the eye to heal without excessive scarring.

The sponsor of this application has not conducted any studies with tranilast. However, it has provided the results of studies in experimental models and of clinical trials from the published literature to support its application for orphan designation.

Tranilast is already marketed in Japan and South Korea for allergic conditions (including allergic conjunctivitis) and scarring of the skin.

At the time of submission, tranilast was not authorised anywhere in the EU for the prevention of scarring post glaucoma filtration surgery 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 8 April 2010 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.