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Orphan designation

On 22 February 2018, orphan designation (EU/3/18/1973) was granted by the European Commission to ProQR Therapeutics IV BV, the Netherlands, for 2'-O-(2-methoxyethyl)-modified antisense oligonucleotide targeting exon 13 in the USH2A gene (also known as QR 421a) 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 form of retinitis pigmentosa is caused by a mutation (change) in the USH2A gene responsible for the production of a protein called usherin, which is essential for the normal functioning of retinal cells. This mutation leads to the production of a faulty usherin protein.

This medicine is an ‘antisense oligonucleotide’, a small strand of synthetic genetic material. It has been designed to attach to the mutated genetic material of retinal cells after injection into the eye, and restore production of a functioning form of usherin. This is expected to result in improvement in the symptoms of the condition.

What is the stage of development of this medicine?

At the time of submission of the application for orphan designation, the evaluation of the effects of the medicine in experimental models was ongoing.

At the time of submission, no clinical trials with the medicine in patients with retinitis pigmentosa had been started.

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>2'-O-(2-Methoxyethyl)-modified antisense oligonucleotide targeting exon 13 in the USH2A gene</p>
Active substance2'-O-(2-Methoxyethyl)-modified antisense oligonucleotide targeting exon 13 in the USH2A gene
Medicine Name
Disease/conditionTreatment of retinitis pigmentosa
Date of decision22/02/2018
Orphan decision numberEU/3/18/1973

Review of designation

Sponsor’s contact details

ProQR Therapeutics IV BV
Zernikedreef 9
2333 CK Leiden
The Netherlands
Tel. +31 88 166 7000

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.