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Orphan designation

On 4 December 2008, orphan designation (EU/3/08/591) was granted by the European Commission to Summit (Oxford) Limited, UK, for 5-(ethylsulfonyl)-2-(naphthalen-2-yl)benzo[d]oxazole for the treatment of Duchenne muscular dystrophy.

The sponsorship was transferred to BioMarin Europe Ltd., United Kingdom, in May 2009 and subsequently to Summit (Oxford) Limited, United Kingdom, in March 2011.

This medicine is now known as ezutromid.             


What is Duchenne muscular dystrophy?

Duchenne muscular dystrophy (DMD) is an inherited genetic disease characterised by progressive weakening of the muscles. It mainly affects boys, usually before the age of six years. The muscle weakness usually starts in the hips and legs, before reaching the chest, arms, and possibly the heart. Patients with DMD do not produce enough of a protein called dystrophin. As dystrophin is an important component of muscle fibres, the muscles of patients with DMD cannot grow, so they become weak and eventually stop working.

Duchenne muscular dystrophy causes long-term disability and is life-threatening because of its effects on the heart and on respiratory muscles (muscles that are used to breathe).

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

At the time of designation, DMD affected approximately 0.3 in 10,000 people in the European Union (EU). This was below the threshold for orphan designation, which is 5 in 10,000, and is equivalent to a total of around 15,000 people*. This is based on the information provided by the sponsor and 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 502,800,000 (Eurostat 2008).

What treatments are available?

At the time of submission of the application for orphan drug designation, there were no treatments available in the EU that could cure DMD. The main treatments for the disease were corticosteroids to slow down the progression of the disease, and physiotherapy, which was used to relieve symptoms and improve the patient’s general condition.

The sponsor has provided sufficient information to show that 5-(ethylsulfonyl)-2-(naphthalen-2-yl)benzo[d]oxazole might be of potential significant benefit for patients because of the way the medicine is expected to work. This could improve the overall outcome of patients with DMD. This assumption will need to be confirmed at the time of marketing authorisation, in order to maintain the orphan status.

How is this medicine expected to work?

The medicine is thought to promote the production of utrophin A, a protein that is similar to dystrophin. This protein is expected have a similar effect to dystrophin on muscles and therefore relieve the symptoms of DMD.

What is the stage of development of this medicine?

The effects of 5-(ethylsulfonyl)-2-(naphthalen-2-yl)benzo[d]oxazole have been evaluated in experimental models.

At the time of submission of the application for orphan designation, no clinical trials in patients with DMD had been started.

At the time of submission, 5-(ethylsulfonyl)-2-(naphthalen-2-yl)benzo[d]oxazole was not authorised anywhere in the world for DMD or designated as 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 October 2008 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>5-(Ethylsulfonyl)-2-(naphthalen-2-yl)benzo[d]oxazole (ezutromid)</p>
Active substance5-(Ethylsulfonyl)-2-(naphthalen-2-yl)benzo[d]oxazole (ezutromid)
Medicine Name
Disease/conditionTreatment of Duchenne muscular dystrophy
Date of decision04/12/2008
Orphan decision numberEU/3/08/591

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:

Summit (Oxford) Limited
136a Eastern Avenue
Milton Park
OX14 4SB
United Kingdom
Tel. +44 (0)1235 443 940
Fax +44 (0)1235 443 999

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.