EU/3/10/750: Orphan designation for the treatment of tuberculosis

Tuberculosis (TB) is an infectious disease caused by bacteria called Mycobacterium tuberculosis. People become infected by inhaling infected droplets from the cough or sneeze of people who have the disease. TB primarily affects the lungs (when it is called pulmonary TB) but it can also spread to other parts of the body, such as the bones or the nervous system. The symptoms of TB include persistent cough, fever, weight loss and night sweats. Not everyone infected will develop the symptoms of the disease.

TB is a long-term debilitating disease. When left untreated, the disease may be life-threatening, mainly because of the severe damage to the lungs that does not allow the patient to breathe normally.

At the time of designation, TB affected not more than 2 in 10,000 people in the European Union (EU)*. This was equivalent to a total of not more than 101,000 people, and is below the threshold 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. At the time of designation, this represented a population of 506,300,000 (Eurostat 2010).

At the time of designation, several antibiotics were authorised in the EU to treat TB. These were used in combination and for long periods of time, normally at least six months.

The sponsor has provided sufficient information to show that rifapentine might be of significant benefit for patients with TB because its use with other existing antibiotics might shorten the total treatment duration by up to three months. This assumption will need to be confirmed at the time of marketing authorisation, in order to maintain the orphan status.

Rifapentine is similar to a group of antibiotics known as rifamycin antibiotics, which include rifampicin. These are the antibiotics most used in the treatment of TB. Rifapentine works by blocking enzymes known as RNA polymerases, which the bacteria need to produce proteins. By blocking these enzymes, rifapentine is expected to stop the growth of the bacteria, eventually killing them.

Because of its chemical structure and the way it works in the body, rifapentine used in combination with other medicines is expected to be able to treat TB more quickly than current combinations do.

The effects of rifapentine have been evaluated in experimental models.

At the time of submission of the application for orphan designation, clinical trials with rifapentine in patients with TB were ongoing.

At the time of submission, rifapentine was authorised and designated as an orphan medicinal product in the United States for pulmonary TB.

In accordance with Regulation (EC) No 141/2000 of 16 December 1999, the COMP adopted a positive opinion on 3 March 2010 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.