EU/3/17/1943 - orphan designation for treatment of mucopolysaccharidosis type II (Hunter's syndrome)

recombinant adeno-associated viral vector serotype 9 containing human iduronate-2-sulfatase gene

Overview

On 12 October 2017, orphan designation (EU/3/17/1943) was granted by the European Commission to Regenxbio EU Limited, Ireland, for recombinant adeno-associated viral vector serotype 9 containing human iduronate-2-sulfatase gene (also known as RGX-121) for the treatment of mucopolysaccharidosis type II (Hunter's syndrome).

What is mucopolysaccharidosis type II (Hunter's syndrome)?

Mucopolysaccharidosis type II (also known as Hunter's syndrome) is an inherited disease that is caused by the lack of an enzyme called iduronate-2-sulfatase. This enzyme is needed to break down substances in the body called glycosaminoglycans (GAGs). Since patients with mucopolysaccharidosis type II cannot break these substances down, the GAGs gradually build up in most of the organs in the body and damage them. This causes a wide range of symptoms, particularly difficulty breathing, difficulty walking, mental disability and behavioural problems. Without treatment, these symptoms become more severe over time.

Mucopolysaccharidosis type II primarily affects male patients. It is a seriously debilitating and life-threatening disease that leads to mental disability and death during youth.

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

At the time of designation, mucopolysaccharidosis type II affected less than 1 in 10,000 people in the European Union (EU). This was equivalent to a total of fewer than 52,000 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).

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*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 28), Norway, Iceland and Liechtenstein. This represents a population of 515,700,000 (Eurostat 2017).

What treatments are available?

At the time of designation, the medicine Elaprase (idursulfase) was authorised in the EU for the treatment of mucopolysaccharidosis type II. This is an enzyme replacement therapy which works by replacing the enzyme that patients are lacking. Some patients underwent transplantation to receive haematopoietic (blood) stem cells that are able to produce the missing enzyme.

The sponsor has provided sufficient information to show that the medicine might be of significant benefit for patients with mucopolysaccharidosis type II because laboratory studies showed that behavioural problems and problems with thinking, learning and memory, which are currently not treatable by the authorised enzyme replacement therapy product, improved with a single treatment of the medicine. This assumption will need to be confirmed at the time of marketing authorisation, in order to maintain the orphan status.

How is this medicine expected to work?

This medicine is made of a virus containing the gene for the iduronate-2-sulfatase enzyme, which is lacking in patients with mucopolysaccharidosis type II. When injected into the patient's brain, the virus is expected to carry the gene into the brain cells, enabling the cells to start producing the enzyme. As a result, the cells will be able to break down the GAGs in the brain, thereby helping to relieve problems of behaviour, thinking, learning and memory.

The type of virus used in this medicine ('adeno-associated virus') does not cause disease in humans.

What is the stage of development of this medicine?

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

At the time of submission of the application for orphan designation, no clinical trials with the medicine in patients with mucopolysaccharidosis type II had been started.

At the time of submission, the medicine was not authorised anywhere in the EU for mucopolysaccharidosis type II. Orphan designation of the medicine had been granted in the EU and the United States for this condition.

In accordance with Regulation (EC) No 141/2000 of 16 December 1999, the COMP adopted a positive opinion on 5 October 2017 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 EU) or insufficient returns on investment.

EU/3/17/1943: Public summary of opinion on orphan designation: Recombinant adeno-associated viral vector serotype 9 containing human iduronate-2-sulfatase gene for the treatment of mucopolysaccharidosis type II (Hunter’s...

Adopted Reference Number: EMA/694657/2017

Key facts

• Active substance:
  recombinant adeno-associated viral vector serotype 9 containing human iduronate-2-sulfatase gene
• Intended use:
  Treatment of mucopolysaccharidosis type II (Hunter's syndrome)
• Orphan designation status:
  Positive
• EU designation number:
  EU/3/17/1943
• Date of designation:
  12/10/2017
• Sponsor:

  REGENXBIO EU Limited; 25-28 North Wall Quay; Dublin 1 D01H104; Ireland; Tel. [phone]; E-mail: [e-mail]

Review of designation

The Committee for Orphan Medicinal Products reviews the orphan designation of a product if it is approved for marketing authorisation.