Cannabidiol for the treatment of Lennox-Gastaut syndrome - Public summary of opinion on orphan designation

Oct 17, 2026

Public summary of the European Medicines Agency Committee for Orphan Medicinal Products’ positive opinion on orphan designation for cannabidiol in Lennox-Gastaut syndrome. The document explains the condition’s childhood onset and severe, long-term impact, estimates patient prevalence in the EU, outlines available authorised epilepsy medicines at the time, and describes expected mechanisms involving calcium movement and adenosine signaling. It also states the development stage, ongoing clinical trials at submission, and the criteria and implications of orphan designation without marketing authorization.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages4

Reading Time10 min

AccessFree to download

Orphan designation overview

What is Lennox-Gastaut syndrome?

Estimated number of patients

Treatments available at designation

Why cannabidiol may help

Expected mechanism of action

Development stage and regulatory status

Orphan designation criteria and implications

Further information

3 May 2017 EMA/143020/2017 Committee for Orphan Medicinal Products Public summary of opinion on orphan designation Cannabidiol for the treatment of Lennox-Gastaut syndrome On 20 March 2017, orphan designation (EU/3/17/1855) was granted by the European Commission to GW Research Ltd, United Kingdom, for cannabidiol for the treatment of Lennox-Gastaut syndrome . What is Lennox-Gastaut syndrome? Lennox-Gastaut syndrome is a severe form of epilepsy that starts in childhood between 2 and 5 years of age. Patients have different types of seizures (fits), including tonic seizures (muscle contraction lasting few seconds to minutes), atypical absence seizures (during which the person has a blank stare but is still partly aware of their surroundings) and drop seizures (brief loss of muscle tone and consciousness, causing abrupt falls) . Most children with Lennox-Gastaut syndrome experience some degree of learning disability and developmental delay, along with behavioural problems such as hyperactivity and aggression. Lennox-Gastaut syndrome is long-term debilitating due to the seizures, effects on mental function and behavioural problems. What is the estimated number of patients affected by the condition? At the time of designation, Lennox-Gastaut syndrome affected approximately 2 in 10,000 people in the European Union (EU) . This was equivalent to a total of around 103,000 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). What treatments are available? At the time of designation, several epilepsy medicines were authorised in the EU for treatment of seizures in children with Lennox-Gastaut syndrome, including clonazepam, felbamate, lamotrigine, rufinamide, and topiramate . * 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 515,700,000 (Eurostat 2017) . The sponsor has provided sufficient information to show that cannabidiol might be of significant benefit for patients with Lennox-Gastaut syndrome . Results from studies in patients showed that cannabidiol reduced the number of seizures in patients in whom previous treatment failed. This assumption will need to be confirmed at the time of marketing authorisation, in order to maintain the orphan status. How is this medicine expected to work? Cannabidiol is a substance extracted from the Cannabis sativa plant. Although the way this medicine works is not clearly understood, cannabidiol is thought to act on targets that play a role in the movement of calcium in the cells, which in turn is important for the transmission of electrical signals in some nerve cells. As seizures are caused by excessive electrical activity in the brain, altering the movement of calcium is expected to reduce or prevent the seizures in Lennox-Gastaut syndrome . Cannabidiol is also thought to act on adenosine, a chemical messenger in the brain that plays an important role in suppressing seizures. What is the stage of development of this medicine? The effects of cannabidiol have been evaluated in experimental models. At the time of submission of the application for orphan designation, clinical trials with cannabidiol inpatients with Lennox-Gastaut syndrome were ongoing. At the time of submission, cannabidiol was not authorised anywhere in the EU for Lennox-Gastaut syndrome . Orphan designation of cannabidiol had been granted in the United States for this condition. In accordance with Regulation (EC) No 141/2000 of 16 December 1999, the COMP adopted a positive opinion on 16 February 2017 recommending the granting of this designation. Opinions on orphan medicinal product designations are based on the following three criteria

FAQs

When was orphan designation granted for cannabidiol for Lennox-Gastaut syndrome?

Orphan designation (EU/3/17/1855) was granted by the European Commission on 20 March 2017, following a positive COMP opinion adopted on 16 February 2017.

How many patients were estimated to be affected in the European Union at the time of designation?

The document estimates that Lennox-Gastaut syndrome affected about 2 in 10,000 people in the EU, equivalent to around 103,000 people.

What is the proposed way cannabidiol might work in Lennox-Gastaut syndrome?

Cannabidiol is thought to act on targets involved in calcium movement in cells and on adenosine signaling in the brain, both of which are expected to reduce or prevent seizures.

Oct 17, 2026

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