EU/3/22/2665: Orphan designation for the treatment of pyridoxal 5'‐phosphate homeostasis protein deficiency

Pyridoxal-5-phosphate (PLP) is the biologically active form of vitamin B6 and is therefore classified as a B6 vitamer. In patients suffering from pyridoxal 5'-phosphate homeostasis protein deficiency (PLPHP) deficiency, a genetic mutation results in a defect in the protein PLPHP. Although the exact mechanism is not yet fully understood, it is thought that the defect in this protein leads to an imbalance of PLP homeostasis and a resulting decreased activity of PLP-dependent enzymes, causing severe neurological dysfunctions. By supplementing the intake of PLP, the correct balance among B6 vitamers inside the cell can be maintained.

Based on description provided by sponsor

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

• No clinical trials with the medicine in patients with pyridoxal 5'‐phosphate homeostasis protein deficiency 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, if such a method exists, 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