EU/3/18/2065: Orphan designation for the treatment of anthrax

Anthrax is a severe disease caused by infection with bacteria called Bacillus anthracis. The bacteria produce spores that are very resistant and can lay ‘dormant’ (inactive) until they find an organism where they can develop and multiply. Anthrax commonly affects animals such as sheep and cows, but can spread to humans when they are exposed to spores from infected animals or contaminated animal products.

The most severe type of anthrax is inhalation anthrax, which occurs when a person has breathed in the bacteria’s spores. The first symptoms of inhalation anthrax are similar to a cold. Several days after the spores have been inhaled, they grow into new bacteria and start to release toxins, which cause internal bleeding, swelling and the death of tissue.

Anthrax is a life-threatening disease because, if not treated early, it leads to the accumulation of fluid in the lungs, severe inflammation and bleeding of the tissues in the chest and haemorrhagic meningitis (inflammation and bleeding of the membranes that surround the brain and spine).

At the time of designation, anthrax affected less than 0.01 in 10,000 people in the European Union (EU). This was equivalent to a total of fewer than 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 28), Norway, Iceland and Liechtenstein. This represents a population of 517,400,000 (Eurostat 2018).

At the time of designation, several antibiotics were authorised in the EU for the treatment of anthrax.

The sponsor has provided sufficient information to show that obiltoxaximab might be of significant benefit for patients with anthrax because laboratory studies indicate that the medicine may improve survival when used in combination with current treatments. This assumption will need to be confirmed at the time of marketing authorisation, in order to maintain the orphan status.

Obiltoxaximab is a monoclonal antibody, a type of protein which has been designed to recognise and attach to a component of anthrax toxin called ‘anthrax protective antigen’ that allows the toxin to lock onto and enter cells. By attaching to the protective antigen in this way, the medicine is expected to stop the toxin from entering the body’s cells, thereby reducing the symptoms of the disease.

The effects of obiltoxaximab 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 anthrax had been started.

At the time of submission, the medicine was not authorised anywhere in the EU for anthrax. Orphan designation was granted in the United States for the treatment of exposure to B. anthracis spores.

In accordance with Regulation (EC) No 141/2000 of 16 December 1999, the COMP adopted a positive opinion on 19 July 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.