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Orphan designation

On 26 January 2005, orphan designation (EU/3/04/260) was granted by the European Commission to Zymenex A/S, Denmark, for recombinant human α-mannosidase for the treatment of α-mannosidosis.

What is α-mannosidosis?

α-mannosidosis is an inherited disease leading to an accumulation of oligosaccharides (small molecules composed of sugars) in the body. α-mannosidosis is due to a lack of α-mannosidase, an enzyme (a protein that speed up the conversion of certain substances into other substances) needed for the breaking down of oligosaccharides. The most severe form (type 1) occurs before 1 year of age. Clinical features include deafness and profound mental retardation. The juvenile/adult form (type 2) is less severe. Milder mental retardation occurs later, but hearing loss is a prominent feature. α-mannosidosis is chronically debilitating and life-threatening.

What are the methods of treatment available?

At the time of submission of the application for the orphan drug designation there was no treatment authorised in the European Union. Treatment of α-mannosidosis included supportive care and bonemarrowtransplantation.

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

According to the information provided by the sponsor, α-mannosidosis was considered to affect about 460 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?

It is assumed that, once admininistrated to the patient, recombinant human α-mannosidase will act as the original α-mannosidase and break down the oligosaccharides, thus preventing the negative effects due to their accumulation in the body. 

What is the stage of development of this medicinal product?

The evaluation of the effects of recombinant human α-mannosidase in experimental models is ongoing. At the time of submission of the application for orphan designation, no clinical trials in patients with α-mannosidosis were initiated. Recombinant human α-mannosidase was not marketed anywhere worldwide for α-mannosidosis 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 8 December 2004 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>Recombinant human alpha-Mannosidase</p>
Active substanceRecombinant human alpha-Mannosidase
Medicine Name
Disease/conditionTreatment of alpha-mannosidosis
Date of decision26/01/2005
Orphan decision numberEU/3/04/260

Review of designation

Sponsor’s contact details:

Zymenex A/S
Roskildevej 12C
DK-3400 Hillerød
Telephone: +45 48 25 00 54
Telefax: +45 48 25 10 54

Patients’ associations contact points:

VML : Vaincre les Maladies Lysosomales
2 Ter Avenue de France
91300 Massy Palaiseau
Telephone: +33 1 69 75 40 30
Telefax : +33 1 60 11 15 83

AIMPS : Associazione Italiana Mucopolisaccaridosi e Malattie Affini - ONLUS
Via Savona 13
20144 Milano
Telephone : +39 02 83 24 12 92
Telefax: +39 02 89 42 51 80

CLIMB - Children Living with Inherited Metabolic Diseases
Climb Building,
176 Nantwich Road
CW2 6BG.
United Kingdom
Telephone: +44 (0)800 65 23 181
E-mail : or