On 12 June 2009, orphan designation (EU/3/09/643) was granted by the European Commission to Targeon SAS, France, for desipramine chlorhydrate for the treatment of Rett syndrome.
- What is Rett syndrome?
Rett syndrome is a genetic disease that is caused by abnormalities in the MECP2 gene, which has important information for the normal functioning of nerve cells. This gene is in the X chromosome, one of the two chromosomes (X and Y) that determine the gender. Rett syndrome almost exclusively affects girls (XX). Boys (XY) have only one X chromosome and if affected they usually don’t survive until birth. Although the disease is genetic, most girls affected (over 95%) do not inherit it from their parents.
Girls with Rett syndrome have severe mental retardation, which first appears between six and 18 months of age. Other symptoms include difficulty breathing, irregular heartbeat, a gradual loss of the ability to move, feeding difficulties, sleeping problems, constipation, repetitive hand movements and seizures (fits).
Rett syndrome is a seriously debilitating and life-threatening disease mainly because of problems with breathing and the heart rhythm.
- What is the estimated number of patients affected by the condition?
At the time of designation, Rett syndrome affected approximately 0.4 in 10,000 people in the European Union (EU)*. This is equivalent to a total of 20,000 people, and is below the threshold for orphan designation, which is 5 people in 10,000. 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. This represents a population of 504,800,000 (Eurostat 2009).
- What treatments are available?
At the time of designation, no satisfactory methods were authorised in the EU for treating Rett syndrome. Girls with the disease were given physiotherapy, speech therapy and nutritional support to help relieve the symptoms of the disease. Medicines to control seizures were also used, as well as laxatives and painkillers.
- How is this medicine expected to work?
Desipramine chlorhydrate has been used in the treatment of depression since the 1960s. In Rett syndrome, the medicine is expected to treat breathing problems.
Girls with Rett syndrome tend to have low levels of norepinephrine, a substance in the brain and spinal cord that helps maintain a normal breathing rhythm. Desipramine chlorhydrate is a ‘norepinephrine re-uptake inhibitor’. This means that it works by increasing the levels of norepinephrine in the spaces between nerve cells in the brain and spinal cord. This is expected to restore normal breathing rhythm in girls with Rett syndrome.
- What is the stage of development of this medicine?
The effects of desipramine chlorhydrate have been evaluated in experimental models.
At the time of submission of the application for orphan designation, a clinical trial in girls with Rett syndrome was ongoing.
At the time of submission, desipramine chlorhydrate was not authorised anywhere in the EU for Rett syndrome 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 5 May 2009 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 Community) 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.
|Name||Language||First published||Last updated|
|EU/3/09/643: Public summary of positive opinion for orphan designation of desipramine chlorhydrate for the treatment of Rett syndrome||(English only)||01/07/2009||11/11/2011|
|Active substance||Desipramine chlorhydrate|
|Disease/condition||Treatment of Rett syndrome|
|Date of decision||12/06/2009|
|Orphan decision number||EU/3/09/643|
Review of designation
Sponsor’s contact details
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Tel. +33 1 5373 1564
Fax +33 1 5373 1564
Patient associations’ contact points
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.