Clinical Takeaway
Plant-derived cannabidiol (CBD) oral solution produced meaningful reductions in drop seizures in patients with Lennox-Gastaut syndrome at thresholds below the conventional 50% benchmark used in clinical trials. Caregiver-reported outcomes aligned with objective seizure data, supporting the validity of caregiver global impression scales as reliable measures of real-world treatment impact. Clinicians should consider that even modest seizure frequency reductions may represent significant functional gains for patients and families managing this severe epilepsy syndrome.
#21 Clinically Meaningful Reduction in Drop Seizures in Patients with Lennox-Gastaut Syndrome Treated with Cannabidiol: Post Hoc Analysis of Phase 3 Clinical Trials.
Citation: Specchio Nicola et al.. Clinically Meaningful Reduction in Drop Seizures in Patients with Lennox-Gastaut Syndrome Treated with Cannabidiol: Post Hoc Analysis of Phase 3 Clinical Trials.. CNS drugs. 2025. PMID: 40775196.
Design: 5 Journal: 0 N: 2 Recency: 2 Pop: 2 Human: 1 Risk: -2
This post hoc analysis identifies clinically meaningful cannabidiol-induced reductions in drop seizures below the traditional 50% threshold, which could expand treatment benefit recognition in Lennox-Gastaut syndrome patients who experience partial but still functionally significant seizure improvement. By correlating seizure frequency reductions with caregiver-reported outcomes via the CGIC scale, the study provides evidence-based guidance for clinicians to counsel patients and families on realistic therapeutic expectations and identify responders who may have been classified as non-responders under conventional efficacy criteria. This work is particularly relevant for a severe, drug-resistant population where even modest seizure reductions can substantially reduce injury risk and improve quality of life.
Quality Gate Alerts:
- Preclinical only
Abstract: BACKGROUND AND OBJECTIVE: In clinical trials of patients with Lennox-Gastaut syndrome (LGS), a ≥ 50% reduction in drop seizure frequency is generally accepted as a key endpoint. However, smaller reductions (< 50%) may yet be impactful for patients in real-world settings. This exploratory analysis evaluated the threshold for a clinically important response in drop seizures that is associated with the Caregiver Global Impression of Change (CGIC) scale score in patients with LGS treated with cannabidiol (CBD) oral solution and assessed the suitability of CGIC as an anchor for meaningful change. METHODS: This exploratory post hoc analysis included patients with LGS (N = 215, age 2-55 years) receiving CBD (Epidiolex® [USA]/Epidyolex® [EU]; 100 mg/mL oral solution) in two phase 3 randomized placebo-controlled trials (NCT02224690, April-October 2015, and NCT02224560, June- December 2015). Reduction in drop seizures (involving sudden loss of muscle tone) was anchored to CGIC scores of "slightly improved" or better or "much improved" or better, to determine the threshold at which seizure reduction can be considered clinically meaningful to patients. Spearman's correlation indicated suitability of anchors (absolute value ≥ 0.30 deemed appropriate). RESULTS: In the 215 patients receiving CBD with a CGIC score recorded, CGIC was "slightly improved" or better in 60% of patients, and "much improved" or better in 31% after 14 weeks of treatment. With a CGIC rating of "slightly improved" or better, the best threshold for a clinically important response in drop seizure reduction was – 30.6% (57.7% of patients). Mean and median percentage reductions in drop seizures were – 46.9% and – 58.6%, respectively. Using "much improved" or better, the best threshold was – 49.6% (40.5% of patients). Mean and median percentage reductions in drop seizures were – 57.6% and – 66.0%, respectively. Spearman's correlation was 0.47. CONCLUSION: Anchoring to CGIC of "slightly improved" or better, the th
🧠 This post hoc analysis of cannabidiol trials in Lennox-Gastaut syndrome usefully explores whether seizure reductions below the conventional 50% threshold can still produce meaningful clinical benefit as perceived by caregivers, an important question given the severity and burden of drop seizures in this population. The strength of the study lies in its use of the Caregiver Global Impression of Change as a real-world outcome measure that captures functional impact beyond raw seizure counts. However, post hoc analyses are inherently exploratory and prone to multiple comparisons bias, and the findings may not generalize to all patient populations or clinical settings, particularly those with different baseline seizure frequencies or comorbidities. Additionally, caregiver perception, while valuable, can be influenced by factors beyond seizure reduction such as medication side effects, cognitive changes, or expectations. For clinical practice, these data suggest that even modest improvements in drop seizure frequency in LGS patients deserve attention and discussion with families, and that shared decision-making should not