EU/3/13/1102: Orphan designation for the treatment of high-altitude pulmonary oedema

High-altitude pulmonary oedema (HAPE) is a condition that occurs at high altitude in otherwise healthy people in which the alveoli (structures at the end of the airways in the lungs where the oxygen is absorbed) fill up with fluid. This results in difficulty breathing, chest tightness, cyanosis (bluish coloration of the skin and mucous membranes due to low oxygen levels in the blood), tachypnoea (rapid breathing) and tachycardia (rapid heartbeat).

HAPE is caused by the way the body reacts to the lack of oxygen at high altitude. It usually occurs after rapid ascent to altitudes of 3,000 m and higher. It usually happens in people who are not acclimatised to such altitudes but the reasons why only some people develop it are not known.

HAPE is a life-threatening medical emergency with a death rate of between 24 and 44% because the symptoms get rapidly worse if left untreated.

At the time of designation, HAPE affected less than 0.03 in 10,000 people in the European Union (EU). This was equivalent to a total of fewer than 1,500 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 27), Norway, Iceland and Liechtenstein. This represents a population of 509,000,000 (Eurostat 2013).

At the time of designation, there were no satisfactory treatments for HAPE. The best option was to bring the patients down to a lower altitude as quickly as possible while administering oxygen. Some medicines including nifedipine, steroids, beta agonists, phosphodiesterase-5 inhibitors and diuretics were also used, although they were not authorised for treating this condition.

The medicine is designed to attach to and 'open' sodium channels (called ENaC) in the cells of the alveoli. Opening the sodium channels leads to the movement of sodium and water out of the alveoli, helping to clear the build-up of fluid. This medicine is therefore expected to improve absorption of oxygen and reduce the life-threatening symptoms of the condition, thereby improving the chances of survival.

The medicine is expected to be taken by inhalation.

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 medicinal product in patients had been started.

At the time of submission, the medicinal product was not authorised anywhere in the EU for HAPE 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 9 January 2013 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.