EU/3/12/998: Orphan designation for the treatment of Wiskott-Aldrich syndrome

Wiskott-Aldrich syndrome is an inherited disease, seen almost exclusively in males, that affects blood cells and cells of the immune system (the body's natural defences). It is caused by abnormalities in the gene that produces the Wiskott-Aldrich syndrome protein (WASP), found in blood cells and certain immune cells. Because patients with the condition lack the WASP protein, their immune cells and blood cells do not develop and function normally.

Patients with Wiskott-Aldrich syndrome have problems with bruising and bleeding easily because they have too few normal platelets (components that help the blood to clot), frequent infections because they have too few normal immune cells and eczema (itchy, red rash). In addition, there is a higher risk of developing some types of cancer, such as lymphoma.

Wiskott-Aldrich syndrome is life-threatening and long-term debilitating due to recurrent infections that could lead to sepsis (when bacteria and their toxins circulate in the blood and starts damaging the organs), bleeding episodes and cancer.

At the time of designation, Wiskott-Aldrich syndrome affected approximately 0.01 in 10,000 people in the European Union (EU). This was equivalent to a total of around 500 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. At the time of designation, this represented a population of 509,000,000 (Eurostat 2012).

At the time of designation, no satisfactory methods were authorised in the EU for Wiskott-Aldrich syndrome. A minority of patients was able to receive a bone marrow transplant (those at a very young age and having a compatible donor).

This medicine is made up of immature bone marrow cells (called CD34+ cells) that are taken from the patient. These cells are able to develop into different types of blood and immune cells. To make this medicine, the cells are modified by a virus that contains the gene for the WASP protein, so that this gene is carried into the cells. When these modified cells are transplanted back into the patient, they are expected to populate the bone marrow and produce healthy blood and immune cells that produce the WASP protein, which is lacking in patients with Wiskott Aldrich syndrome, and thereby help to relieve the symptoms of the disease.

The type of virus used in this medicine ('lentivirus') is modified in order not to cause disease in humans.

The effects of the medicine have been evaluated in experimental models.

At the time of submission, clinical trials with the medicine in patients with Wiskott-Aldrich syndrome were ongoing.

At the time of submission, the medicine was not authorised anywhere in the EU for Wiskott-Aldrich syndrome. Orphan designation of the medicine had been granted in the United States of America for the treatment of Wiskott-Aldrich syndrome.

In accordance with Regulation (EC) No 141/2000 of 16 December 1999, the COMP adopted a positive opinion on 12 April 2012 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.