A CBD/THC cannabis oil reduced seizures by 70.6% in children with Dravet syndrome in an open-label trial | Research

The takeaway

A prospective open-label trial of 20 children with Dravet syndrome treated with a CBD-dominant cannabis oil (100 mg/mL CBD, 2 mg/mL THC) found a median motor seizure reduction of 70.6%, a 50% responder rate of 63%, significant EEG improvement, and improved quality of life over 20 weeks.

Pediatric neurologists treating Dravet syndrome; parents considering cannabis-based therapies for epilepsy; researchers studying CBD/THC combination therapies.

70.6% median motor seizure reduction with 63% responder rate

What the researchers found

Twenty children with Dravet syndrome received add-on therapy with TIL-TC150, a cannabis oil containing 100 mg/mL CBD and 2 mg/mL THC.

Doses ranged from 2-16 mg/kg/day of CBD (mean achieved: 13.3 mg/kg/day) and 0.04-0.32 mg/kg/day of THC (mean: 0.27 mg/kg/day).

Nineteen of 20 participants completed the 20-week intervention.

Results showed a median motor seizure reduction of 70.6%, with 63% of patients achieving at least 50% seizure reduction.

There was a statistically significant improvement in quality of life and reduction in EEG spike activity.

Adverse events during titration included somnolence, anorexia, and diarrhea. Liver enzyme and platelet abnormalities were observed in patients also taking valproic acid.

The study provided the first safety and dosing data for THC-containing cannabis preparations in Dravet syndrome, complementing the pure CBD (Epidiolex) trial data.

Why it matters

While pure CBD (Epidiolex) trials have established CBD for Dravet syndrome, this study adds evidence that a CBD-dominant oil containing small amounts of THC is also safe and effective, with a notably high 70.6% median seizure reduction that compares favorably to pure CBD trial results.

The numbers in context

20 children, 19 completed 20 weeks. Mean CBD dose: 13.3 mg/kg/day (range 7-16). Mean THC dose: 0.27 mg/kg/day (range 0.14-0.32). Median motor seizure reduction: 70.6%. 50% responder rate: 63%. Significant QOL improvement and EEG spike reduction.

How the study worked

Prospective open-label trial. 20 children with Dravet syndrome. TIL-TC150 (Tilray cannabis oil: 100 mg/mL CBD, 2 mg/mL THC) as add-on therapy for 20 weeks. Monitored for seizure frequency, EEG changes, quality of life, and adverse events.

What this study cannot tell us

Open-label design without placebo control, so true drug effect is uncertain. Small sample of 20 patients. Adverse events overlapped with those of concomitant medications (particularly valproic acid). 20-week duration may not capture long-term tolerance or adverse effects.

How to read the evidence

Moderate. Prospective design with multiple outcome measures, but open-label without placebo control limits certainty about true drug effect.

When this study was published

Published in 2018. CBD-based epilepsy treatments have since gained wider approval and clinical use.

The bigger picture

The inclusion of low-dose THC alongside CBD is notable because the entourage effect theory suggests whole-plant extracts may work differently than pure isolates. The high response rate in this open-label trial supports further investigation of CBD/THC combination products for severe epilepsy.

Questions still open

Does the low-dose THC component contribute to efficacy beyond CBD alone? Would a randomized comparison of CBD/THC oil versus pure CBD show differences? Are the liver enzyme changes from the cannabis oil, valproic acid interaction, or both?

Common questions

How does this compare to pure CBD (Epidiolex) trials?

The 70.6% median seizure reduction and 63% responder rate in this open-label study compare favorably to the ~39-40% reductions seen in randomized Epidiolex trials. However, open-label studies typically show larger effects than placebo-controlled trials due to expectation effects, so direct comparison is not straightforward.

Why include THC in a treatment for children?

The THC dose was very low (0.27 mg/kg/day on average, about 50 times less than the CBD dose). Some researchers believe small amounts of THC may enhance CBD's therapeutic effects through the entourage effect. The study monitored carefully for THC-related adverse effects.

Read the original research

A prospective open-label trial of a CBD/THC cannabis oil in dravet syndrome.

Annals of clinical and translational neurology, 5(9), 1077-1088

View on PubMed ↗Publisher’s paper ↗

Citation

McCoy, Bláthnaid; Wang, Laura; Zak, Maria; Al-Mehmadi, Sameer; Kabir, Nadia; Alhadid, Kenda; McDonald, Kyla; Zhang, Grace; Sharma, Rohit; Whitney, Robyn; Sinopoli, Katia; Snead, O Carter. (2018). A prospective open-label trial of a CBD/THC cannabis oil in dravet syndrome.. Annals of clinical and translational neurology, 5(9), 1077-1088. https://doi.org/10.1002/acn3.621