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Orphan designation

On 5 March 2012, orphan designation (EU/3/12/972) was granted by the European Commission to NDA Regulatory Science Ltd, United Kingdom, for sialic acid for the treatment of hereditary inclusion body myopathy.

The sponsorship was transferred to NDA Group AB, Sweden, in December 2013 and subsequently to Ultragenyx UK Limited, United Kingdom, in April 2015.

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

What is hereditary inclusion body myopathy?

Hereditary inclusion body myopathy is an inherited muscle-wasting disease. Patients with the disease have a mutation in a gene responsible for a protein that is involved in the production of sialic acid. Sialic acid is a sugar important in the development of muscles. A lack of sialic acid is believed to be the cause of the wasting of muscles seen in people with this condition. The disease worsens over time as more muscles become affected, progressively reducing mobility and eventually confining the patient to a wheelchair.

Hereditary inclusion body myopathy is a life-threatening and long-term debilitating condition due to progressive muscle wasting which leads to a complete inability of the patient to live independently.

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

At the time of designation, hereditary inclusion body myopathy affected approximately 0.004 in 10,000 people in the European Union (EU). This was equivalent to a total of around 200 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. At the time of designation, this represented a population of 512,200,000 (Eurostat 2013).

What treatments are available?

At the time of designation, no satisfactory treatments were authorised for hereditary inclusion body myopathy in the EU. Patients received treatment to relieve their symptoms such as physiotherapy to improve muscle strength, and other physical supports to aid mobility.

How is this medicine expected to work?

As a lack of sialic acid is believed to cause the muscle wasting in this condition, this medicine is expected to work by providing the missing sialic acid that the patients need. It is thought that sialic acid may act on various proteins involved in muscle development, such as ‘the neural cell adhesion molecule’, which helps to ensure that nerve cells are properly connected to the muscle cells. The medicine is being developed as ‘extended release’ tablets, designed to release the active substance over an extended period in view of the fact that sialic acid is quickly removed from the blood and a constant supply of sialic acid is needed to improve muscle function in this condition.

What is the stage of development of this medicine?

The effects of sialic acid have been evaluated in experimental models.

At the time of submission of the application for orphan designation, clinical trials with sialic acid in patients with hereditary inclusion body myopathy were ongoing.

At the time of submission, sialic acid was not authorised anywhere in the EU for hereditary inclusion body myopathy. Orphan designation of sialic acid had been granted in the United States of America for hereditary inclusion body myopathy.

In accordance with Regulation (EC) No 141/2000 of 16 December 1999, the COMP adopted a positive opinion on 11 January 2012 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>Sialic acid</p>
Active substanceSialic acid
Medicine Name
Disease/conditionTreatment of hereditary inclusion body myopathy
Date of decision05/03/2012
Orphan decision numberEU/3/12/972

Review of designation

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

Related information

Sponsor’s contact details

Ultragenyx UK Limited
c/o Regus
Level 33, 25 Canada Square
Canary Wharf
London E14 5LB
Tel. +44 (0)20 7038 8025
Fax +44 (0)20 7038 8100

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.