EU/3/18/2026: Orphan designation for the treatment of transthyretin-mediated amyloidosis (ATTR amyloidosis)

Transthyretin-mediated amyloidosis (ATTR amyloidosis) belongs to a group of diseases called systemic amyloidosis in which deposits of proteins (called amyloids) accumulate and cause damage in body organs. In ATTR amyloidosis, the amyloids are made up of transthyretin, a protein produced in the liver that transports various substances in the blood.

In patients with ATTR amyloidosis, transthyretin deposits build up mainly in the heart and the nervous system. Patients with this condition usually have heart problems and symptoms such as muscle weakness in the limbs and, at later stages, inability to walk, problems affecting the stomach and the gut (leading to malnutrition), and bladder dysfunction.

ATTR amyloidosis is a long-term debilitating disease due to the progressive worsening of nervous system symptoms. It is also life threatening because amyloid deposits in the heart can cause fatal heart conditions.

At the time of designation, ATTR amyloidosis affected less than 0.2 in 10,000 people in the European Union (EU). This was equivalent to a total of fewer than 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, the only medicine authorised in the EU to treat ATTR amyloidosis was Vyndaqel (tafamidis). Vyndaqel was authorised to delay nerve damage caused by ATTR amyloidosis in patients with the early stage of nerve disease. The only other treatment option was liver transplantation.

The sponsor has provided sufficient information to show that the medicine might be of significant benefit for patients with all forms of ATTR amyloidosis. Early studies indicated that the way the medicine works could make it effective in a broader patient group than current treatments.

This assumption will need to be confirmed at the time of marketing authorisation, in order to maintain the orphan status.

The medicine is made of a small strand of synthetic genetic material, called 'small interfering RNA' (siRNA), that stops the gene for transthyretin from working and thereby blocks the production of transthyretin in the liver. This is expected to reduce transthyretin deposits in the tissues and thus relieve the symptoms of the disease.

The effects of the medicine have been evaluated in experimental models.

At the time of submission of the application for orphan designation, no clinical trials with the medicine in patients with ATTR amyloidosis had been started.

At the time of submission, the medicine was not authorised anywhere in the EU for ATTR amyloidosis 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 19 April 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.