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Orphan designation

On 2 April 2012, orphan designation (EU/3/12/979) was granted by the European Commission to Aptiv Solutions (UK) Limited, United Kingdom, for sodium thiosulfate for the treatment of calciphylaxis.

What is calciphylaxis?

Calciphylaxis, also known as calcific uraemic arteriolopathy, is a severe and progressive disease mainly seen in patients with end-stage kidney disease (when the kidneys have stopped working). It involves the build up of calcium in the very small arteries causing a restricted blood supply and small clots. The skin is affected with the appearance of skin ulcers (sores) that do not heal and usually cause severe pain.

Calciphylaxis is a long-term debilitating and life-threatening condition, particularly due to the deep, painful, non-healing ulcers and the risk of infection.

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

At the time of designation, calciphylaxis affected less than 0.5 in 10,000 people in the European Union (EU)*. This is equivalent to a total of fewer than 25,000 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 506,300,000 (Eurostat 2011).

What treatments are available?

At the time of application, no satisfactory methods were authorised in the EU to treat calciphylaxis. Treatments included medicines to reduce the build up of calcium in the arteries, skin wound management and surgery.

How is this medicine expected to work?

Sodium thiosulfate is expected to act as a ‘calcium chelator’. This means that it is expected to attach to calcium to form a compound which is easily eliminated in the urine, thereby reducing the build up of calcium in the arteries seen in patients with calciphylaxis. It is also thought to act as an antioxidant (a molecule that may prevent damage to cells caused by other molecules known as ‘free radicals’), which may help restore the healthy functioning of cells lining the interior walls of the arteries.

What is the stage of development of this medicine?

At the time of submission of the application for orphan designation, no preclinical studies in experimental models had been performed. However, the sponsor provided results of studies from the published literature.

At the time of submission, no clinical trials with sodium thiosulfate in patients with calciphylaxis had been started.

At the time of submission, sodium thiosulfate was not authorised anywhere in the EU for calciphylaxis 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 February 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>Sodium thiosulfate</p>
Active substanceSodium thiosulfate
Medicine Name
Disease/conditionTreatment of calciphylaxis
Date of decision02/04/2012
Orphan decision numberEU/3/12/979

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:

Aptiv Solutions (UK) Limited
100 Milton Park
Oxfordshire OX14 4RY
United Kingdom
Telephone: +44 131 449 8877
Telefax: +44 131 449 8889

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.