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Orphan designation

On 27 July 2005, orphan designation (EU/3/05/297) was granted by the European Commission to Généthon, France, for adeno-associated viral vector containing modified U7 snRNA gene for the treatment of Duchenne muscular dystrophy.

What is Duchenne muscular dystrophy?

Duchenne muscular dystrophy is an inherited genetic disease with onset usually before the age of 6. It is characterised by symmetrical progressive diminishing and weakness of the muscles, first at the height of the pelvis and legs, later on also the muscles of the chest and arms are involved. Genes located on structures present in each cell of the body (the chromosomes), carry the genetic information that determines the characteristics of each individual. In humans, the so-called X and Y-chromosomes determine the sex, but carry also other genetic information. Duchenne muscular dystrophy is caused by an abnormality of a gene located on the X chromosome. This gene is responsible for the production of a protein, dystrophin, in the muscle cells. This means that patients suffering from this condition do not produce the dystrophin protein or produce a non-functional dystrophin. As boys, contrary to girls, only have one single copy of chromosome X, thus one single copy of dystrophin gene, they have much higher pobabilities of suffering from Duchenne muscular distrophy. Duchenne muscular dystrophy is chronically debilitating and life-threatening.

What are the methods of treatment available?

At the time of submission of the application for orphan designation, no satisfactory method had been authorised in the European Union for treatment of the condition. Treatment of patients with Duchenne muscular dystrophy primarily involves physiotherapy as supportive treatments. 

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

According to the information provided by the sponsor, Duchenne muscular dystrophy was considered to affect about 23,000 persons in the European Union.

*Disclaimer: For the purpose of the designation, the number of patients affected by the condition is estimated and assessed based on data from the European Union (EU 25), Norway, Iceland and Lichtenstein. This represents a population of 459,700,000 (Eurostat 2004). This estimate is based on available information and calculations presented by the sponsor at the time of the application. 

How is this medicinal product expected to act?

Adeno-associated viral vector containing modified U7 snRNA gene is a medicinal product, which in theory might overcome the abnormality in the production of dystrophin. The product would allow skipping the abnormal parts of the gene responsible for the lack of functional dystrophin production. Thus it could enable the production of shorter versions of the dystrophin protein, but still capable of ensuring the same functions as the normal full-length dystrophin. 

What is the stage of development of this medicinal product?

The evaluation of the effects of adeno-associated viral vector containing modified U7 snRNA gene in experimental models is ongoing. At the time of submission of the application for orphan designation, no clinical trials in patients with Duchenne muscular dystrophy were initiated. Adeno-associated viral vector containing modified U7 snRNA gene was not marketed anywhere worldwide for Duchenne muscular dystrophy, at the time of submission.
According to Regulation (EC) No  141/2000 of 16 December 1999, the Committee for Orphan Medicinal Products (COMP) adopted on 15 June 2005 a positive opinion recommending the grant of the above-mentioned designation.

Opinions on orphan medicinal products designations are based on the following cumulative criteria:
  • the seriousness of the condition,
  • the existence or not of alternative methods of diagnosis, prevention or treatment and
  • either the rarity of the condition (considered to affect not more than five in ten thousand persons in the Community) or the insufficient return of development investments. 

Designated orphan medicinal products are still investigational products which were considered for designation on the basis of potential activity. An orphan designation is not a marketing authorisation. As a consequence, demonstration of the quality, safety and efficacy will be necessary before this product can be granted a marketing authorisation.

Key facts

Product details for <p>Adeno-associated viral vector containing a modified U7 snRNA gene</p>
Active substanceAdeno-associated viral vector containing a modified U7 snRNA gene
Medicine Name
Disease/conditionTreatment of Duchenne muscular dystrophy
Date of decision27/07/2005
Orphan decision numberEU/3/05/297

Review of designation

Sponsor’s contact details

1 bis rue de l’internationale
91000 Evry
Tel. +33 169 47 29 17
Fax +33 169 47 19 46

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.