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Orphan designation

On 22 February 2018, orphan designation (EU/3/18/1975) was granted by the European Commission to Nightstar Therapeutics plc, the United Kingdom, for adenovirus-associated viral vector serotype 8 containing the human RPGR gene for the treatment of retinitis pigmentosa.

What is retinitis pigmentosa?

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.

Retinitis pigmentosa is a long-term debilitating disease because it causes the patient’s sight to get worse, eventually leading to blindness.

What is the estimated number of patients affected by the condition?

At the time of designation, retinitis pigmentosa affected approximately 3 in 10,000 people in the European Union (EU). This was equivalent to a total of around 155,000 people*, and is below the ceiling for orphan designation, which is 5 people in 10,000. This isbased 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 517,400,000 (Eurostat 2018).

What treatments are available?

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 damage to the retina, genetic counselling (discussion of the risks of passing the condition on to children) and general support.

How is this medicine expected to work?

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 these mutations the RPGR protein is lacking.

The medicine consists of a virus that contains a working 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 work better, reducing progression of the condition.

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

What is the stage of development of this medicine?

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

At the time of submission, clinical trials with the medicine in patients with retinitis pigmentosa were ongoing.

At the time of submission, the medicine was not authorised anywhere in the EU for retinitis pigmentosa 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 January 2018 recommending the granting of this designation.

Opinions on orphan medicinal product designations are based on the following three criteria:
  • 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.

Key facts

Product details for <p>Adenovirus-associated viral vector serotype 8 containing the human RPGR gene</p>
Active substanceAdenovirus-associated viral vector serotype 8 containing the human RPGR gene
Medicine Name
Disease/conditionTreatment of retinitis pigmentosa
Date of decision22/02/2018
Orphan decision numberEU/3/18/1975

Review of designation

Sponsor’s contact details

Nightstar Therapeutics plc
Gibbs Building
215 Euston Road
London NW1 2BE
United Kingdom
Tel. +44 (0)20 7611 2077

Patients’ organisations

For contact details of patients’ organisations whose activities are targeted at rare diseases, see:

  • Orphanet, a database containing information on rare diseases, which includes a directory of patients’ organisations registered in Europe;
  • European Organisation for Rare Diseases (EURORDIS), a non-governmental alliance of patient organisations and individuals active in the field of rare diseases.