Phase III RCTs led to FDA approval of Epidiolex (pharmaceutical CBD) for Dravet and Lennox-Gastaut syndromes, marking the first cannabis-derived medication approved by a national regulatory agency, though its use for other epilepsy syndromes remains undetermined.
Neurologists, families of children with severe epilepsy, and anyone following the regulatory path of cannabis-derived medicines.
First FDA-approved CBD drug
What the researchers found
Epidiolex (>99% CBD, <0.10% THC) received FDA approval for Dravet and Lennox-Gastaut syndromes and EMA approval for Lennox-Gastaut syndrome, based on Phase III RCTs and open-label trials demonstrating efficacy and safety. CBD mechanism of action remains unknown and does not appear to work through cannabinoid receptors.
Why it matters
Epidiolex approval represents a watershed moment: the first time a cannabis-derived compound passed the full regulatory approval process. It validates the therapeutic potential of cannabinoids while setting a standard for evidence-based cannabis medicine.
The numbers in context
Epidiolex: >99% CBD, <0.10% THC. FDA approved for Dravet and Lennox-Gastaut syndromes. EMA approved for Lennox-Gastaut syndrome. Based on Phase III RCTs and open-label trial data.
How the study worked
Review of the history, pharmacology, and clinical trial data supporting CBD approval for epilepsy, including Phase III RCTs and prospective open-label trials.
What this study cannot tell us
Approval is limited to two rare epilepsy syndromes. CBD mechanism of action is still unknown. The review does not address effectiveness of non-pharmaceutical cannabis products for epilepsy. Long-term safety data is still accumulating.
How to read the evidence
Rated strong because the approval was based on Phase III randomized controlled trials meeting full regulatory standards.
When this study was published
Published in 2019, shortly after FDA approval. Additional indications and post-market data have continued to accumulate.
The bigger picture
The Epidiolex approval demonstrates that cannabis-derived compounds can meet the same rigorous standards as any other medication. It also highlights how far the field needs to go, as the complete spectrum of cannabis-derived products and their use for other conditions remains to be determined.
Questions still open
- Will CBD receive approval for other epilepsy types? What is its anti-seizure mechanism if not through cannabinoid receptors? How do non-pharmaceutical cannabis products compare in efficacy and safety?
Common questions
What is Epidiolex?
Does CBD work for all types of epilepsy?
How does CBD stop seizures?
Read the original research
Cannabinoid therapy in epilepsy.
Current opinion in neurology, 32(2), 220-226
Citation
Billakota, Santoshi; Devinsky, Orrin; Marsh, Eric. (2019). Cannabinoid therapy in epilepsy.. Current opinion in neurology, 32(2), 220-226. https://doi.org/10.1097/WCO.0000000000000660
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