EU/3/18/1999: Orphan designation for the treatment of haemophilia B

Haemophilia B is an inherited bleeding disorder caused by the lack of factor IX, a protein involved in the blood coagulation (clotting) process. Patients with haemophilia B are more prone to bleeding than normal and have poor wound healing after injury or surgery. Internal bleeding can also happen within muscles or in the joints, such as the elbows, knees and ankles. This can lead to permanent damage if it happens repeatedly.

Haemophilia B is a debilitating disease that is life long and may be life threatening because bleeding can also happen in the brain and spinal cord, the throat or the gut.

At the time of designation, haemophilia B affected approximately 0.2 in 10,000 people in the European Union (EU). This was equivalent to a total of around 10,000 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 28), Norway, Iceland and Liechtenstein. This represents a population of 517,400,000 (Eurostat 2018).

At the time of designation, medicines containing factor IX were authorised in the EU for the treatment of haemophilia B, to replace the missing protein. However, factor IX medicines did not work in some patients with haemophilia B because the immune system (the body's natural defences) can produce 'inhibitors' (antibodies) against factor IX which stop the factor IX medicine from working. In these cases, other treatments needed to be used, such as factor VIIa (the activated form of factor VII, another protein involved in blood clotting), either alone or as part of a combination treatment.

The sponsor has provided sufficient information to show that the medicine might be of significant benefit for patients with haemophilia B because laboratory studies show that it can increase the amount of factor IX circulating in the blood. The way the medicine works means that patients may not need or may need less frequent treatment with factor IX medicines. This assumption will need to be confirmed at the time of marketing authorisation, in order to maintain the orphan status.

In patients with haemophilia B, the gene for producing factor IX is defective, which stops them making factor IX.

This medicine is made of a virus that contains normal copies of the gene responsible for producing factor IX. When injected into the patient's vein, it is expected that the virus will be carried to the liver where the gene will be taken up into the patient's liver cells and start producing factor IX. It is expected that a single dose of the medicine will maintain raised levels of factor IX for a long time thereby reducing bleeding.

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

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

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

At the time of submission, the medicine was not authorised anywhere in the EU for haemophilia B or designated as an orphan medicinal product elsewhere for this condition.

In accordance with Regulation (EC) No 141/2000 of 16 December 1999, the COMP adopted a positive opinion on 15 February 2018 recommending the granting of this designation.

• 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.