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Orphan designation

On 19 June 2013, orphan designation (EU/3/13/1141) was granted by the European Commission to Alan Irvine, Ireland, for synthetic double-stranded siRNA oligonucleotide directed against the keratin 6a N171K mutation for the treatment of pachyonychia congenita.

For a list of the administrative updates to this public summary of opinion, please refer to the PDF document below.

What is pachyonychia congenita?

Pachyonychia congenita is an inherited skin condition in which the patient has symptoms such as painful blisters and callouses on the palms and soles of the feet, thickened finger and toe nails, and lesions on the inside of the mouth.
Pachyonychia congenita is caused by mutations (defects) in the genes for keratin, the tough fibrous protein found in the skin and nails. A patient normally has a 50% chance of passing it on to their offspring as one defective gene from one parent is usually enough for a person to have the condition.

Pachyonychia congenita is a chronically debilitating disease because the painful blisters and callouses make walking difficult or impossible.

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

At the time of designation, pachyonychia congenita affected less than 0.02 in 10,000 people in the European Union (EU). This was equivalent to a total of fewer than 1,000 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. This represents a population of 509,000,000 (Eurostat 2013).

What treatments are available?

At the time of the application for orphan designation, no satisfactory methods were authorised in the EU for treating pachyonychia congenita. Treatment focused on the relief of symptoms, personal hygiene to help blisters heal, to avoid infections and to protect the skin from damage and the treatment of any infections that may occur in the affected skin.

How is this medicine expected to work?

The medicine is made of a small strand of synthetic genetic material, called ‘small interfering RNA’ (siRNA) that interferes with the function of certain genes. It has been designed to target a defective gene called KRT6a causing pachyonychia congenita in some people, where it is expected to block the production of the abnormal keratin and reverse the disease by restoring the ability of the cells in the skin to produce normal keratin.

What is the stage of development of this medicine?

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 pachyonychia congenita had been started.

At the time of submission, the medicinal product was not authorised anywhere in the EU for pachyonychia congenita 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 15 May 2013 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>synthetic double-stranded siRNA oligonucleotide directed against the keratin 6a N171K mutation</p>
Active substancesynthetic double-stranded siRNA oligonucleotide directed against the keratin 6a N171K mutation
Medicine Name
Disease/conditionTreatment of pachyonychia congenita
Date of decision19/06/2013
Orphan decision numberEU/3/13/1141

Review of designation

The Committee for Orphan Medicinal Products reviews the orphan designation of a product if it is approved for marketing authorisation.

Sponsor’s contact details

Prof. Alan Irvine
Professor of Dermatology
Our Lady's Children's Hospital Crumlin
Dublin 12
Tel. +35 314 282 532
Fax +35 314 742 408

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.