On 19 November 2014, orphan designation (EU/3/14/1376) was granted by the European Commission to Orphazyme ApS, Denmark, for arimoclomol citrate for the treatment of Niemann-Pick disease, type C.

In October 2020, Orphazyme ApS changed name to Orphazyme A/S.

Niemann-Pick disease is a group of inherited disorders belonging to the larger family of metabolic disorders called 'lysosomal storage diseases', in which fats accumulate within lysosomes (parts of the body's cells that break down nutrients and other materials).

In Niemann-Pick disease type C, there is a lack of transporter proteins that are needed to move fatty substances such as cholesterol and other fats within cells, leading to the build-up of these fats in the brain and elsewhere in the body (such as the spleen and liver). This causes a wide range of symptoms, including behavioural problems, learning disabilities and difficulty moving and speaking.

Niemann-Pick disease type C is chronically debilitating and life threatening since the build-up of fatty substances can cause brain damage and swelling of organs such as the spleen and the liver.

At the time of designation, Niemann-Pick disease type C affected approximately 0.1 in 10,000 people in the European Union (EU). This was equivalent to a total of around 5,000 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 511,100,000 (Eurostat 2014).

At the time of designation, Zavesca (miglustat) was authorised in the EU to treat Niemann-Pick disease, type C.

The sponsor has provided sufficient information to show that arimoclomol citrate might be of significant benefit for patients with Niemann-Pick disease type C because it works in a different way to miglustat and experimental studies suggest it might be of benefit in reducing the symptoms of the disease.This assumption will need to be confirmed at the time of marketing authorisation, in order to maintain the orphan status.

In Niemann-Pick disease type C the build-up of fatty substances in the lysosomes reduces their ability to function normally and makes the membrane around the lysosome unstable. Arimoclomol is a medicine that stimulates the cell's natural mechanisms for coping with damage, by increasing the production of proteins called heat shock proteins in cells that are under stress. These proteins help to stabilise the membrane around the lysosomes and improve the ability of the lysosome to function and break down certain fats. This is expected to help reduce the symptoms of the disease.

The effects of arimoclomol citrate have been evaluated in experimental models.

At the time of submission of the application for orphan designation, no clinical trials with arimoclomol citrate in patients with Niemann-Pick disease, type C had been started.

At the time of submission, arimoclomol citrate was not authorised anywhere in the EU for Niemann-Pick disease type C 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 9 October 2014 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.

Key facts

Active substance
arimoclomol citrate
Intended use
Treatment of Niemann-Pick's disease, type C
Orphan designation status
EU designation number
Date of designation

Zevra Denmark A/S
Ole Maaloees Vej 3
2200 Copenhagen N
E-mail: lhimmelstrup@kempharm.com

Review of designation

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

Update history

March 2023The sponsor’s name was changed from KemPharm Denmark A/S to Zevra Denmark A/S.
February 2023The sponsorship was transferred from Orphazyme A/S, Denmark to KemPharm Denmark A/S., Denmark.

EMA list of opinions on orphan medicinal product designation

EMA publishes information on orphan medicinal product designation adopted by the Committee for Orphan Medicinal Products (COMP) on the IRIS online platform:

Patients' organisations

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

  • European Organisation for Rare Diseases (EURORDIS), a non-governmental alliance of patient organisations and individuals active in the field of rare diseases.

  • Orphanet, a database containing information on rare diseases, which includes a directory of patients’ organisations registered in Europe.

EU register of orphan medicines

The list of medicines that have received an orphan designation in the EU is available on the European Commission's website:

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