Two national NHS clinical trials are scheduled to commence in 2025 to investigate the potential of cannabidiol (CBD) and tetrahydrocannabinol (THC) in treating adults and children with refractory epilepsy. The studies, co-led by Prof Finbar O’Callaghan and Prof Helen Cross from University College London (UCL) and Great Ormond Street Hospitals (GOSH), aim to provide robust evidence on the safety and effectiveness of these cannabis-based medicines.
The trials will adopt a randomized, double-blind, placebo-controlled design, assigning participants to receive either CBD, CBD with a small amount of THC, or a placebo for a duration of 24 weeks. A total of 500 individuals with medicine-resistant, early-onset, and genetic generalized epilepsies will be recruited from NHS sites across the UK. The formulations used in the trial, MRX2 (CBD) and MRX2T (CBD+THC), are provided by Ananda Developments.
The primary objective of the research is to assess whether these medicines can safely and effectively reduce the frequency and severity of seizures. Secondary endpoints include evaluating the impact of CBD and THC on various aspects of patients' lives, such as learning, sleep, behavior, quality of life, stress, and anxiety.
Current Treatment Landscape and Unmet Needs
Currently, Epidyolex, a CBD medicine, is licensed and recommended for use within the NHS for individuals with Dravet syndrome and Lennox-Gastaut syndrome. However, the National Institute for Health and Care Excellence (NICE) has not recommended this medicine for severe and treatment-resistant epilepsies, citing the need for more high-quality evidence on the safety and effectiveness of CBD, both alone and in combination with THC.
Rebekah Smith, deputy chief executive at Epilepsy Action, highlighted the importance of this research, stating, “It’s encouraging to see these long-anticipated trials for medicinal cannabis finally taking place… The need for more research on the effectiveness and safety of both the CBD and THC elements of cannabis is much needed, and announcing this research is a source of hope for many families.”
Potential Regulatory Implications
If the trials demonstrate positive outcomes, the results could support applications to the Medicines and Healthcare Products Regulatory Agency (MHRA) and other regulatory bodies for the approval of these cannabis-based medicines for use in refractory epilepsy. Ananda Developments emphasized that these trials will be the world’s first double-blind randomized controlled trials to investigate the combined use of CBD and THC for epilepsy, and the first to evaluate these medicines in both children and adults with a broad range of difficult-to-treat epilepsies.
Matt Hughes, co-founder and director of Medcan Family Foundation, noted the significance of including THC in the trials to address the questions posed by NICE. However, he also pointed out that the trials do not include second-generation, advanced cannabinoid medicines, which some families find more effective. He urged government support for creating a pathway for the licensing of these more advanced medications.
