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Orphan designation

On 11 January 2012, orphan designation (EU/3/11/940) was granted by the European Commission to Miragen Therapeutics Europe Ltd, United Kingdom, for chimeric locked nucleic acid-deoxynucleoside phosphorothioate-linked oligonucleotide directed against microRNA-451 for the treatment of polycythaemia vera.

Please note that this product was withdrawn from the Community Register of designated Orphan Medicinal Products in April 2017 on request of the Sponsor.

What is polycythaemia vera?

Polycythaemia vera is a disease in which the bone marrow (the spongy tissue inside the large bones where blood cells are produced) produces too many red blood cells. This makes the blood thicker and can result in reduced blood flow to the organs and occasionally the formation of blood clots. While some patients with polycythaemia vera do not have any symptoms, others may have itching, tiredness, headache, blurred vision and an enlarged liver and spleen. Patients who develop blood clots in the small blood vessels can also experience a wide range of symptoms including burning pains in the hands. Patients with blood clots in the arteries can have strokes.

Polycythaemia vera is a long-term debilitating and life-threatening condition because it may lead to the formation of blood clots and bleeding, and can result in leukaemia (cancer of the white blood cells) and myelofibrosis (a disease of the bone marrow).

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

At the time of designation, polycythaemia vera affected approximately 3 in 10,000 people in the European Union (EU)*. This is equivalent to a total of around 152,000 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).

*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 506,300,000 (Eurostat 2011).

What treatments are available?

At the time of designation, hydroxycarbamide, pipobroman and busulfan were authorised in some Member States to reduce the number of red blood cells in patients with polycythaemia vera. In addition, phlebotomy (removal of some of the blood from the body) and long-term treatment with low-dose aspirin were recommended in some patients to reduce the risk of blood clot formation.

The sponsor has provided sufficient information to show that this medicine might be of significant benefit for patients with polycythaemia vera because it works in a different way to existing treatments and early studies in experimental models show that it might improve the treatment of patients with this condition. 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 an ‘anti-sense oligonucleotide’ medicine. It is expected to work by blocking a molecule called ‘microRNA-451’. MicroRNA-451 is found in high levels inside blood cells, where it is thought to regulate their production. By blocking microRNA-451, the abnormal production of red blood cells is expected to decrease, relieving the symptoms of polycythaemia vera.

What is the stage of development of this medicine?

At the time of submission of the application for orphan designation, the evaluation of the effects of this medicine in experimental models was ongoing.

At the time of submission, no clinical trials with the medicine in patients with polycythaemia vera had been started.

At the time of submission, the medicine was not authorised anywhere in the EU for polycythaemia vera. Orphan designation of the medicine had been granted in the United States of America for this condition.

In accordance with Regulation (EC) No 141/2000 of 16 December 1999, the COMP adopted a positive opinion on 9 November 2011 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.

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.

Key facts

Product details for <p>Chimeric locked nucleic acid-deoxynucleoside phosphorothioate-linked oligonucleotide directed against microRNA-451</p>
Active substanceChimeric locked nucleic acid-deoxynucleoside phosphorothioate-linked oligonucleotide directed against microRNA-451
Medicine Name
Disease/conditionTreatment of polycythaemia vera
Date of decision11/01/2012
Orphan decision numberEU/3/11/940

Review of designation

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

Sponsor’s contact details:

Miragen Therapeutics Europe Ltd
90 High Holborn
London WC1V 6XX
United Kingdom
Tel. +44 (0)20 7067 3918

Patients' organisations:

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.