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. 2025 May 19:19:1570531.
doi: 10.3389/fnins.2025.1570531. eCollection 2025.

19 patients report seizure freedom with medical cannabis oil treatment for drug-resistant epilepsy: a case series

Frank Yizhao Chen #  1   2 , Joshua Myles Duckman #  1 , Brenden Samuel Rabinovitch  1   3   4 , Katrin Julia Hannesson  1 , Evan Cole Lewis  1   5
Affiliations

19 patients report seizure freedom with medical cannabis oil treatment for drug-resistant epilepsy: a case series

Frank Yizhao Chen et al. Front Neurosci. .

Abstract

Purpose: Seizure freedom (SF) is the primary goal of epilepsy treatment. More treatments that produce SF in drug-resistant epilepsy (DRE) are needed. Cannabis-based products for medicinal use (CBPMs) containing cannabidiol (CBD) and Δ9-tetrahydrocannabinol (THC), administered as oils, have been shown to induce SF in DRE. However, there remains a paucity of published real-world evidence in both pediatrics and adults on SF resulting from CBPM therapy.

Methods: This is a retrospective case series at an outpatient neurology clinic in Toronto, Canada, on patients with DRE who experienced significant SF during CBPM treatment. All patients were treated via the clinic's stepwise treatment protocol with CBPM oils only. The study describes clinical features of patients and their CBPM-related SF.

Results: We report 19 DRE cases that experienced SF; 15 pediatric, 4 adults. The median cumulative SF duration was 245 days, split between continuous SF periods lasting at least 90 days. Five patients had continuous SF periods lasting ≥ 1 year. Most patients used CBD+THC regimens. Three patients weaned all concomitant ASMs. Adverse events (AEs) were reported by half of the patients.

Conclusion: The results of the study support prioritizing CBPMs in cases of DRE. It also supports research into identifying clinical and biological biomarkers for DRE cases that may achieve SF under CBPM treatment. Lastly, the study supports improving the accessibility of CBPMs, using SF as a primary outcome in future CBPM epilepsy trials, and assessing the role of THC in reducing seizures.

Keywords: CBD–cannabidiol; THC–tetrahydrocannabinol; cannabis; cannabis medicine; epilepsy; pediatric epilepsy; seizure freedom; seizures.

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Conflict of interest statement

FYC is currently employed by Avicanna, and was previously employed by JMCC during the study. BSR held a MITACS Accelerate Fellowship sponsored by Avicanna for unrelated work with a different group. ECL previously held an unpaid advisory role at JMCC Group and has been paid for speaking engagements with Jazz Pharmaceuticals, Avicanna Inc. MGC Pharmaceuticals, and Argent BioPharma. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The authors declare that this study received funding from Avicanna Inc. and JMCC Group. Avicanna had the following involvement in the study: requesting the collection and publication of Supplementary Table 4 data. The funders had no other involvement in the study design, collection, analysis, interpretation of data, the writing of this article, or the decision to submit it for publication.

Figures

FIGURE 1
FIGURE 1
Flow chart of data extraction timeline with inclusion and exclusion criteria.
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