EU/3/16/1665: Orphan designation for the treatment of retinitis pigmentosa caused by mutations in the RPGR gene

Retinitis pigmentosa is a group of hereditary diseases of the eye that lead to progressive loss of sight. In patients with retinitis pigmentosa, cells in the retina (the light-sensitive surface at the back of the eye) become damaged and eventually die.

One of the causes of retinitis pigmentosa is mutations (changes) in the RPGR gene responsible for the production of the RPGR protein, which is necessary for the normal functioning of retinal cells. In patients with this form of the disease the RPGR protein is lacking.

Retinitis pigmentosa caused by mutations in the RPGR gene is a long-term debilitating disease because it causes the patient's sight to get worse, eventually leading to blindness.

At the time of designation, retinitis pigmentosa caused by mutations in the RPGR gene was estimated to affect approximately 0.7 in 10,000 people in the European Union (EU). This was equivalent to a total of around 36,000 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 28), Norway, Iceland and Liechtenstein. This represents a population of 513,700,000 (Eurostat 2016).

At the time of designation, no satisfactory methods were authorised in the EU for treating retinitis pigmentosa. Patients with the condition were given sunglasses to slow down the damage to the retina, genetic counselling (discussion of the risks of passing the condition on to children) and general support.

The medicine consists of a virus that contains a normal copy of the RPGR gene. When injected into the patient's eye, under the retina, it is expected that the virus will carry the RPGR gene into the retinal cells, enabling them to produce the missing RPGR protein. This is then expected to help the cells in the retina to function better, reducing progression of the condition.

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

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

At the time of submission of the application for orphan designation, no clinical trials with the medicine in patients with retinitis pigmentosa caused by mutations in the RPGR gene had been started.

At the time of submission, the medicine was not authorised anywhere in the EU for retinitis pigmentosa caused by mutations in the RPGR gene 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 21 April 2016 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.