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Orphan designation

On 27 October 2011, orphan designation (EU/3/11/922) was granted by the European Commission to Prophylix Pharma AS, Norway, for human platelet antigen-1a immunoglobulin for the prevention of fetal and neonatal alloimmune thrombocytopenia due to human platelet antigen-1a incompatibility.

What is fetal and neonatal alloimmune thrombocytopenia due to human platelet antigen-1a incompatibility?

Fetal and neonatal alloimmune thrombocytopenia (FNAIT) due to human platelet antigen-1a incompatibility is a rare disease of foetuses and newborn babies. It occurs when the foetus’ platelets (a type of blood cell) produce certain antigens (structures that a body can recognise as 'foreign') which are not normally found in the mother’s body. These antigens are called ‘human platelet antigen-1a’ (HPA-1a). If they enter the mother’s blood, then the mother's immune system responds by producing antibodies (proteins in the blood that help the body fight infections and diseases). These antibodies attack the blood platelets in the foetus, causing thrombocytopenia (low blood platelet counts). Because platelets are involved in blood clotting, the foetus or newborn baby is at risk of severe bleeding.

FNAIT is chronically debilitating and life threatening since it can lead to intracranial haemorrhage (bleeding within the skull) in the foetus or newborn baby, which can cause miscarriage, still birth, death of the newborn baby or permanent damage to the brain and nerves.

What is the estimated number of patients at risk of developing the condition?

At the time of designation, the number of patients at risk of fetal and neonatal alloimmune thrombocytopenia due to HPA-1a incompatibility was estimated to be approximately 2.8 people in 10,000 in the European Union (EU)*. This is equivalent to a total of 142,000 people, which 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 methods of prevention are available?

At the time of designation, no satisfactory methods were authorised in the EU for the prevention of FNAIT due to HPA-1a incompatibility.

How is this medicine expected to work?

The medicine consists of anti-HPA-1a immunoglobulins, taken from the blood of a suitable female donor containing antibodies against HPA-1a. Immunoglbulins are antibodies that attack certain antigens, in this case HPA-1a. When the medicine is injected into the mother’s blood, it is expected to work by destroying the HPA-1a platelets produced by the foetus before the mother’s immune system reacts against them. In this way the immune system reaction from the mother’s body against the foetus platelets can be avoided, thus preventing the occurrence of fetal or neonatal alloimmune thrombocytopenia due to HPA-1a incompatibility.

What is the stage of development of this medicine?

The effects of HPA-1a immunoglobulin have been evaluated in experimental models.

At the time of submission of the application for orphan designation, no clinical trials with HPA-1a immunoglobulin had been started.

At the time of submission, HPA-1a immunoglobulin was not authorised anywhere in the EU for fetal and neonatal alloimmune thrombocytopenia due to HPA-1a incompatibility or designated as an orphan medicinal product anywhere in the world for this condition.

In accordance with Regulation (EC) No 141/2000 of 16 December 1999, the COMP adopted a positive opinion on 8 September 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>Human platelet antigen-1a immunoglobulin</p>
Active substanceHuman platelet antigen-1a immunoglobulin
Medicine Name
Disease/conditionPrevention of fetal and neonatal alloimmune thrombocytopenia
Date of decision27/10/2011
Orphan decision numberEU/3/11/922

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:

Prophylix Pharma AS
N-9294 Tromsø
Telephone: +47 95 10 36 05
Telefax: +47 77 67 97 50

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.