Cannabidiol with clobazam for treating seizures associated with Lennox–Gastaut syndrome
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1.1 Cannabidiol with clobazam is not recommended, within its anticipated marketing authorisation for treating seizures associated with Lennox–Gastaut syndrome in people aged 2 years and older.
1.2 This recommendation is not intended to affect treatment with cannabidiol that was started in the NHS before this guidance was published. People having treatment outside this recommendation may continue without change to the funding arrangements in place before this guidance was published, until they and their NHS clinicians consider it appropriate to stop. For children and young people, this decision should be made jointly by the clinician and the child or young person, or the child or young person's parents or carers.
Why the committee made these recommendations
This appraisal looks at whether people with Lennox–Gastaut syndrome taking cannabidiol with clobazam have a better quality of life and live longer than those who don't. It also assesses whether using it reflects a good use of limited NHS resources.
Current treatment for Lennox–Gastaut syndrome includes antiepileptic drugs (often 2 or more). People with Lennox–Gastaut syndrome would use cannabidiol with clobazam if 2 other antiepileptic drugs have not adequately controlled drop seizures.
Clinical trial evidence shows that, in people with Lennox–Gastaut syndrome, cannabidiol reduces the number of drop and non-drop seizures when compared with usual care. There is trial evidence for only 14 weeks, so the longer-term effectiveness of cannabidiol is uncertain.
The cost-effectiveness estimates for cannabidiol with clobazam compared with usual care are very uncertain. This is partly because the company's economic model is unreliable and its results favour cannabidiol, even when assuming the drug is not effective. Also, the model may not capture all aspects of Lennox–Gastaut syndrome that are important to people with the condition. This means that it is not possible to identify a true estimate of cost effectiveness. Because these issues remain unresolved, cannabidiol cannot, at this time, be recommended for use in the NHS. The company is asked to provide more information and amend its model.