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Orphan designation

On 21 March 2018, orphan designation (EU/3/18/2001) was granted by the European Commission to Soligenix UK Ltd., United Kingdom, for recombinant modified ricin toxin A-chain subunit (also known as RiVax) for the prevention of ricin poisoning.

What is ricin poisoning?

Ricin is a highly toxic protein derived from the seeds of the castor oil plant. Ricin poisoning can be intentional (mainly by people attempting suicide) or can happen by mistake, for example in people researching or working with it. It is considered that ricin might also be used in acts of terrorism.

Initial symptoms of ricin poisoning depend on how the poison is given but may include fever, cough, nausea and vomiting (feeling and being sick), shock and difficulty breathing. Ricin poisoning is life-threatening due to multiple organ failure and usually leads to death within a few days.

What is the estimated number of people at risk of ricin poisoning?

At the time of designation, the number of people at risk of ricin poisoning was estimated to be less than 0.001 people in 10,000 in the European Union (EU). This was equivalent to a total of fewer than 50 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 at risk of developing 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).

What methods of prevention are available?

At the time of designation, no satisfactory methods were authorised in the EU for the prevention of ricin poisoning.

How is this medicine expected to work?

This medicine is a copy of part of the ricin toxin which has been inactivated by changing one of its amino acids (the building blocks of proteins). It works like a vaccine, by ‘teaching’ the immune system (the body’s natural defences) how to defend itself against ricin poisoning. When the medicine is given to people at risk of ricin poisoning, the immune system recognises ricin as ‘foreign’ and makes antibodies against it. When the person is then exposed to ricin, these antibodies together with other components of the immune system will be able to destroy the toxin and help protect against poisoning.

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, clinical trials with the medicine in people were ongoing.

At the time of submission, the medicine was not authorised anywhere in the EU for the prevention of ricin poisoning. Orphan designation of the medicine had been granted in the United States.

In accordance with Regulation (EC) No 141/2000 of 16 December 1999, the COMP adopted a positive opinion on 15 February 2018 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.

Key facts

Product details for <p>Recombinant modified ricin toxin A-chain subunit</p>
Active substanceRecombinant modified ricin toxin A-chain subunit
Medicine Name
Disease/conditionPrevention of ricin poisoning
Date of decision21/03/2018
Orphan decision numberEU/3/18/2001

Review of designation

The Committee for Orphan Medicinal Products reviews the orphan designation of a product if it is approved for marketing authorisation.

Sponsor's contact details

Soligenix UK Ltd.
Vision Park
Chivers Way
Cambridge CB24 9AD
United Kingdom
Tel. +44 141 582 1211

Patients' organisations

For contact details of patients’ organisations whose activities are targeted at rare diseases, see:

  • Orphanet, a database containing information on rare diseases which includes a directory of patients’ organisations registered in Europe.
  • European Organisation for Rare Diseases (EURORDIS), a non-governmental alliance of patient organisations and individuals active in the field of rare diseases.