EU/3/21/2507: Orphan designation for the treatment of osteopetrosis

Patients with the most common form of osteopetrosis have a change in a gene needed to make a substance called TCIRG1, which is important for the shaping and structuring of bone (remodelling). The medicine consists of blood stem cells taken from the patient and treated with a modified virus that inserts working copies of the TCIRG1 gene into the stem cells. These are grown outside the body to increase their numbers and given back to the patient, where they eventually help to produce bone shaping cells (osteoclasts) that inherit the working gene and can produce the missing TCIRG1. This is expected to allow more normal bone remodelling and relieve symptoms of the disease. The virus used in this medicine (lentiviral vector) is modified so that it does not cause disease in humans.

Based on description provided by sponsor

At the time of submission of the application for orphan designation:

• The effects of the medicine had been evaluated in experimental models.

• No clinical trials with the medicine in patients with osteopetrosis had been started.

More information on how potential new medicines are tested during their development is available on Authorisation of medicines.

Medicines intended for rare diseases can be granted an orphan designation during their development.

The orphan designation allows the developer to benefit from:

• scientific and regulatory support to advance their medicine to the stage where they can request marketing authorisation;

• market exclusivity once the medicine is on the market.

To qualify for orphan designation, a medicine must meet a number of criteria:

• it must be intended for the treatment, prevention or diagnosis of a disease that is life-threatening or chronically debilitating;

• the prevalence of the condition in the EU must not be more than 5 in 10,000 or it must be unlikely that marketing of the medicine would generate sufficient returns to justify the investment needed for its development;

• there are no satisfactory alternative methods for the diagnosis, prevention or treatment of the condition or the medicine is of significant benefit to those affected by the condition.

EMA's Committee for Orphan Medicinal Products (COMP) is responsible for issuing opinions on applications for orphan designations.

The Agency sends the COMP opinion to the European Commission, which is responsible for granting the orphan designation. The full list of orphan designations is available in the Community register of orphan medicinal products for human use.

For more information, see:

• Orphan designation: Overview

• Rare diseases, orphan medicines: Getting the facts straight