EU/3/07/459: Orphan designation for the treatment of narcolepsy

Narcolepsy is characterised by excessive daytime sleepiness (patients have an irresistible urge to sleep, even in inappropriate times and places), and often have disturbed night sleep with very vivid dreams. In addition, some of the patients experience sudden episodes of severe muscle weakness (called cataplexy), potentially causing dangerous falls. Narcolepsy symptoms can be very severe and damage significantly both the private and professional life of the patients. Cataplexy can increase the risk of accidents, including car accidents. It can occur so suddenly that the patient does not have time to prepare and avoid falls or sudden attacks of sleep urge, for example.

Several products to treat the symptoms of narcolepsy were authorised in the Community at the time of submission of the application for orphan drug designation. 1-{3-[3-(4-chlorophenyl)propoxy]propyl}piperidine may be of potential significant benefit in patients affected by narcolepsy. This will have to be confirmed at the time of marketing authorisation. This will be necessary to maintain the orphan status.

According to the information provided by the sponsor, narcolepsy was considered to affect not more than 230,000 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.

The mechanism of action of 1-{3-[3-(4-chlorophenyl)propoxy]propyl}piperidine in narcolepsy is not fully understood. It may involve regulation of neurotrasnmitters, which are chemical substances produced in the brain and used by brain cells to communicate between themselves, and this may improve the night sleep and indirectly decrease also the daytime symptoms.

The effects of 1-{3-[3-(4-chlorophenyl)propoxy]propyl}piperidine were evaluated in experimental models.

At the time of submission of the application for orphan designation, clinical trials in patients with narcolepsy were ongoing.

1-{3-[3-(4-chlorophenyl)propoxy]propyl}piperidine was not authorised anywhere worldwide for narcolepsy or designated as orphan medicinal product elsewhere for this condition, 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 31 May 2007 a positive opinion recommending the grant of the above-mentioned designation.

• 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.