EU/3/04/233: Orphan designation for the treatment of gamma sarcoglycanopathy

Gamma sarcoglycanopathy is an inherited condition and usually appears in childhood. The abnormal gene is located on a portion of chromosome number 13, and the disease occurs if both parents pass an abnormal version of this gene onto their offspring (this type of disease transmission is called “autosomal recessive” transmission). Patients suffering from this condition are not able to produce a protein called gamma sarcoglycan in the muscle cells. This protein is important for normal functioning of the muscle cells. Gamma sarcoglycanopathy is characterised by progressive weakness of the muscles. Gamma sarcoglycanopathy is chronically debilitating and life-threatening.

At the time of designation, gamma sarcoglycanopathy affected approximately 0.02 in 10,000 people in the European Union (EU). This was equivalent to a total of 1,300 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 25), Norway, Iceland and Liechtenstein. At the time of designation, this represented a population of 464,200,000 (Eurostat 2004).

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 gamma sarcoglycanopathy primarily involved physiotherapy as supportive treatment, but also surgery of the tendon and spine fusion.

Adeno-associated viral vector containing the human gamma sarcoglycan gene is a medicinal product which uses a virus to carry the gene necessary for the production of the gamma sarcoglycan protein. A virus is a small organism capable of introducing genetic material in cells. The type of virus (adenoassociated virus) used in this medicinal product is modified in order to avoid causing any disease in humans.

The evaluation of the effects of adeno-associated viral vector containing the human gamma sarcoglycan gene in experimental models is ongoing.

At the time of submission of the application for orphan designation, no clinical trials in patients with gamma sarcoglycanopathy were initiated.

Adeno-associated viral vector containing the human gamma sarcoglycan gene was not marketed anywhere worldwide for gamma sarcoglycanopathy or designated as orphan medicinal product elsewhere for this condition, at the time of submission.

In accordance with Regulation (EC) No 141/2000 of 16 December 1999, the COMP adopted a positive opinion on 9 September 2004 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.