EU/3/16/1686

On 27 June 2016, orphan designation (EU/3/16/1686) was granted by the European Commission to Mereo Biopharma Group Limited, United Kingdom, for recombinant humanised monoclonal IgG2 lambda antibody against human sclerostin for the treatment of osteogenesis imperfecta.

What is osteogenesis imperfecta?

Osteogenesis imperfecta is a group of inherited disorders that mainly affect the bones. People with the condition have fragile bones which break easily. Other sign and symptoms may include deformity, short stature, large head size (macrocephaly), hearing loss, problems with teeth development, as well as brain and lung complications.

Osteogenesis imperfecta is a seriously debilitating disease due to fragile bones, multiple fractures (broken bones) and deformities, which may cause pain and restrict daily activities.

What is the estimated number of patients affected by the condition?

At the time of designation, osteogenesis imperfecta affected approximately 1 in 10,000 people in the European Union (EU). This was equivalent to a total of 51,000 people*, and is below the ceiling for orphan designation, which is 5 people in 10,000. This isbased on the information provided by the sponsor and the knowledge of the Committee for Orphan Medicinal Products (COMP).

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* 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 513,700,000 (Eurostat 2016).

What treatments are available?

At the time of designation, no satisfactory methods were authorised in the EU for treating osteogenesis imperfecta. Patients were given supportive treatments such as physiotherapy, bracing and surgery to manage the symptoms of the disease. Bisphosphonates were used to reduce the breakdown of the bone.

How is this medicine expected to work?

This medicine is a monoclonal antibody, a type of protein that has been designed to attach to and block a substance called sclerostin, which is produced by mature bone cells. The main function of sclerostin is to prevent excessive bone formation. By blocking sclerostin, this medicine is expected to increase bone formation, thereby strengthening bones and making them less prone to fracture.

The medicine is made by a method known as ‘recombinant DNA technology’: it is made by cells into which a gene (DNA) has been introduced that makes them able to produce the medicine.

What is the stage of development of this medicine?

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

At the time of submission of the application for orphan designation, one clinical trial with the medicine in patients with osteogenesis imperfecta had been completed and further trials were planned.

At the time of submission, the medicine was not authorised anywhere in the EU for osteogenesis imperfecta 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 May 2016 recommending the granting of this designation.

Opinions on orphan medicinal product designations are based on the following three criteria:

• 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.