A new study recently published in leading epilepsy medical journal, Epilepsia, has reported positive findings on the long-term efficacy of CBD in refractory epilepsies.
The study investigated the use of CBD-based medication Epidyolex in 54 patients with refractory epilepsy in a US hospital over a period of up to 5 years.
The study found that from year 1 to the most recent follow-up, CBD maintained its efficacy for controlling seizures. The “most recent follow up” in the study was on average 45.5 months after treatment began, with a maximum treatment period of 60 months. The researchers found that the percentage of seizure responders remained similar at these time points (41.7%–42.6%). A majority of patients exhibited greater than 50% reduction in overall seizure frequency, with 1 in 5 having greater than 90% reduction in seizure frequency.
This is an important finding as there until now there has been very little long-term clinical data around the long-term efficacy of CBD. This is because the medication is relatively new and initial clinical trials only started in the mid-2010s.
Other takeaways from the study noted how the medication was generally well-tolerated by patients – with recorded adverse events being in line with what was known/listed as possible adverse reactions (e.g. diarrhea, drowsiness). The data also suggests that CBD is particularly effective in reducing seizures associated with tuberous sclerosis and also potentially epileptic spasms and absence seizures.
An additional important finding would be that the use of CBD did not generally lead to the withdrawal of other AEDs as part of the patients treatment.
While this study is of course very encouraging, there are a number of possible weaknesses in the study to consider when looking at the study results as a whole:
- The numbers involved are quite small – just 54 participants.
- The study was open label; this means that patients/carers and researchers knew exactly what treatment was being received. This type of study is normally considered to provide a lesser evidence base compared to a study where a placebo was used to measure effectiveness and patients/ researchers were unaware of the treatment they were receiving.
- The study involved a review of patient-reported seizure logs over time, which depends on patients/ carers providing accurate and unbiased information to the researchers in their logs.
You can read further information on this study on the Online Wiley Library website.
We will continue to monitor emerging global research on this matter and will provide updates on our website and social media channels.
In the meantime, you can learn more about Medical Cannabis & Epilepsy by visiting the 'Treatment' section of our website. Please talk to your medical team if you are considering or are using any cannabis-based product in the treatment of your or a family member’s epilepsy.