The efficacy of cannabidiol for seizures reduction in pharmacoresistant epilepsy: a systematic review and meta-analysis

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“Background: Epilepsy is a neurological syndrome caused by excessive neuronal discharges, with a part of the patients being pharmacoresistant to the traditional treatment. Cannabidiol, a non-psychoactive component of Cannabis Sativa, shows promise as an alternative, but further research is needed to quantify its efficacy.

Methods: This literature systematic review was made following the PRISMA protocol guidelines. The Google Scholar, Scielo, and PubMed/MEDLINE databases were included using the descriptors “Cannabidiol”, “Epilepsy”, and “Drug Resistant Epilepsy”. This research was registered in the Prospero platform with the identification (CRD42024479643).

Results: A total of 1448 results were identified from the PubMed, Virtual Health Library, and Google Scholar databases. After applying exclusion criteria, six studies met the criteria for full-text evaluation and eligibility. The compiled analysis showed that the patients who received cannabidiol experienced a 41.0875% reduction in the total number of seizures, compared to an average reduction of 18.1% in placebo groups. This represents a 127% higher response rate for patients who received the intervention.

Conclusions: Given these results, it is possible to conclude that the therapeutic response of cannabidiol is worthy of consideration in new protocols and of being added to public healthcare systems for its antiepileptic potential. However, the high efficacy rate observed in the placebo group suggests that other methods of data collection analysis may be employed.”

https://pubmed.ncbi.nlm.nih.gov/40217555/

“Based on the results from the analyzed studies, it can be concluded that the addition of CBD to the treatment regimen for patients with pharmacoresistant epilepsy is beneficial in most cases. The doses of 10 mg/kg/day and 20 mg/kg/day were compared in 5 out of 6 studies, with a higher dose demonstrating superior seizure control. However, the lower dose also showed significant efficacy, making it a viable option for inclusion in treatment and guidelines as well.”

https://aepi.biomedcentral.com/articles/10.1186/s42494-024-00191-2

Optimization of seizure prevention by cannabidiol (CBD)

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“Objective: Cannabidiol (CBD) is one of the most prominent non-psychotropic cannabinoids with known therapeutic potentials. Based on its anti-seizure efficacy, the first cannabis derived pharmaceutical grade CBD-based medication was approved in the USA in 2018 for the treatment of seizures in patients 2 years and older. Despite the effectiveness in reducing seizures, there remain several major questions on the optimization of CBD therapy for epilepsy such as the optimal dosage, composition, and route of delivery, which are the main objective of this current study.

Methods: We evaluated the antiseizure effects of CBD through different compositions, routes of delivery, and dosages in a pre-clinical model. We used a kainic acid-induced epilepsy model in C57BL/6 mice, treated them with placebo and/or CBD through inhalation, oral, and injection (intraperitoneal) routes. We used CBD broad spectrum (inhaled and intraperitoneal) vs CBD isolate formulations. We employed the Racine scaling system to evaluate the severity of the seizures, flow cytometry for measuring immune biomarkers and neurotrophic factors, and histologic analysis to examine and compare the groups.

Results: Our findings showed that all forms of CBD reduced seizures severity. Among the combination of CBD tested, CBD broad spectrum via inhalation was the most effective in the treatment of epileptic seizures (p < 0.05) compared to other forms of CBD treatments.

Conclusion: Our data suggest that route and CBD formulations affect its efficacy in the prevention of epileptic seizures. Inhaled broad spectrum CBD showed a potential superior effect compared to other delivery routes and CBD formulations in the prevention of epileptic seizures, which warrants further research.”

https://pubmed.ncbi.nlm.nih.gov/40177581/

https://www.degruyterbrill.com/document/doi/10.1515/tnsci-2022-0362/html

[Real-life study with pharmaceutical cannabidiol in refractory epilepsy]

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“Pharmaceutical-grade cannabidiol (CBD) is an alternative treatment for patients with drug-resistant epilepsy (DRE). In 2022, the Italian Hospital of Buenos Aires implemented a non-medical change (NMC) of treatment, replacing one commercial pharmaceutical-grade CBD product with another, the latter also being the initial option for new patients.

Our objective was to evaluate the clinical outcomes of the commercial product change in this population.

Methods: Retrospective cohort of DRE patients who either switched from one commercial pharmaceutical-grade CBD product to another or started treatment with the new product. The clinical response was evaluated by changes in seizure frequency, perception of change with the Patient Global Impression of Change (PGIC) scale, and safety considering discontinuation and/or the presence of adverse effects.

Results: Nineteen patients were included, 12 in the change group and 7 in the new start group (7 pediatric and 12 adults). One patient discontinued treatment due to lack of response. Among those who completed follow-up, 8 (44%) reduced seizure frequency, 6 (33%) showed no change, and 4 (22%) increased seizure frequency. According to the PGIC scale, 9 (50%) remained unchanged, 5 (28%) reported barely noticeable changes, and 4 (22%) reported improvement. Adverse events were mild and transient.

Conclusion: The new commercial pharmaceutical-grade CBD product is a safe and valid option both for substitution and initial treatment in patients with DRE. During the treatment period, patients perceived stability or improvement according to the PGIC scale.”

https://pubmed.ncbi.nlm.nih.gov/40163830/

Antiepileptic activity and potential mechanism of full-spectrum hemp extract

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“Epilepsy is the fourth most common neuropsychiatric disorder. Although the approval of Epidiolex has ignited hope for patients, there is still a large gap in the field of anti-seizure research. The effect and underlying mechanism of full-spectrum hemp extract (HE) remains unclear.

Here this study investigated the anti-seizure effect of HE on seizure models. The results showed that HE significantly reduced seizure susceptibility and prolonged seizure latency with better pharmacokinetic performance compared to CBD.

This article then further explored the anti-seizure active components and their possible mechanism in HE. The results indicated that cannabichromene (CBC) and cannabinol (CBN) were involved in the anti-seizure process, especially CBC showed a strong allosteric enhancement effects on CBD binding site of the GABAA receptor, which implied that the GABAA receptor seemed to be the primary anti-epileptic target of HE.

This article not only presents the great potential of HE as a candidate for new anti-epileptic drugs with less psychoactive, but also provides a valuable contribution to subsequent mechanism research and drug development on epilepsy.”

https://pubmed.ncbi.nlm.nih.gov/40166106/

https://www.sciencedirect.com/science/article/pii/S2667325824004552?via%3Dihub

Expanding the therapeutic role of highly purified cannabidiol in monogenic epilepsies: A multicenter real-world study

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“Objective: This real-world, retrospective, multicenter study aims to investigate the effectiveness of highly purified cannabidiol (CBD) in a large cohort of patients with epilepsy of genetic etiology due to an identified monogenic cause. Additionally, we examine the potential relationship between specific genetic subgroups and treatment response.

Methods: This study was conducted across 27 epilepsy centers and included patients with monogenic epileptic disorders (pathogenic or likely pathogenic variants) who were treated with highly purified CBD for at least 3 months.

Results: A total of 266 patients (135 females, 50.8%) with monogenic epilepsies were included with a median age at CBD initiation of 12 years (interquartile range [IQR] = 7-19) and a median follow-up duration of 17 months (IQR = 12-24). Overall, 77 different monogenic epilepsies have been included, with the most common genes being SCN1A (32.3%), TSC2 (13.5%), CDKL5, and MECP2 (4.5% each). The mean seizure reduction at the last follow-up was 38.6%, with 47.5% of patients achieving ≥50% seizure reduction and 7.4% achieving seizure freedom. The Clinical Global Impression scale indicated improvement in 65.8% of patients. The general linear mixed model revealed that a shorter maximum duration of seizure freedom before CBD initiation and a higher degree of intellectual disability were independently associated with lower CBD effectiveness. Conversely, no significant differences in seizure outcome were observed across different epilepsy syndromes (Lennox-Gastaut syndrome, Dravet syndrome, tuberous sclerosis complex epilepsy, and other developmental and epileptic encephalopathy), between approved indications and off-label use, or between concomitant clobazam use or not.

Significance: This study supports CBD as a potential treatment for monogenic epilepsies beyond its licensed indications, demonstrating comparable effectiveness between approved and off-label use and suggesting genetic subgroups with promising treatment responses.”

https://pubmed.ncbi.nlm.nih.gov/40126049/

Ion channels and G protein-coupled receptors: Cannabidiol actions on disorders of excitability and synaptic excitatory-inhibitory ratio

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“Brain excitability is dysfunctional in epilepsy and overlapping neuropsychiatric conditions including autism spectrum disorder (ASD). Epilepsy and ASD are often attributed to malfunctioning coordination between synaptic excitation and inhibition.

Dravet syndrome (DS) is a severe form of epilepsy arising from haploinsufficiency of the SCN1A gene that encodes the voltage-gated sodium channel Nav1.1. A DS mouse model (Scn1a+/-) recapitulated essential features of DS and revealed that sodium current density was profoundly reduced in GABAergic inhibitory interneurons while pyramidal cells were spared, suggesting that DS is an “interneuronopathy.”

Further studies from the Catterall group and others have expanded this picture: DS symptoms, which include recurrent seizures, ataxia, cognitive impairment, ASD, and premature death, could be assigned in part to brain region-specific effects; the Nav1.1 mutations cause dysfunction in some subtypes of interneurons, not others, and are temporally restricted; DS-causing sodium channel mutations were found throughout SCN1A as well as in SCN1B, encoding the β1 subunit.

Interest in therapeutic approaches was sparked by preclinical studies of cannabidiol (CBD) that led to the 2018 US Food and Drug Administration approval for treatment of seizures in patients with DS. Independent evidence showed that CBD antagonized GPR55, a G protein-coupled receptor activated by the lipid signaling molecule lysophosphatidylinositol (LPI).

We summarized evidence from our group and others that CBD has a dual mechanism of action, targeting both ion channels and GPR55. CBD quells an epileptogenic vicious cycle: seizures strengthen LPI-GPR55 signaling while LPI-GPR55 signaling elevates the synaptic excitatory-inhibitory ratio, thereby promoting further seizures.

SIGNIFICANCE STATEMENT: Modern medicine relies on ion channels and G protein-coupled receptors (GPCRs) as key targets. In studies of Dravet syndrome, a devastating genetic disorder with features of epilepsy and autism, William Catterall connected NaV1.1 mutations to deficient excitability of inhibitory neurons. He and his colleagues explored preclinical interventions using cannabidiol (CBD) and clobazam, opening the way to a current understanding of CBD’s therapeutic mechanism. CBD affects both ion channels and GPR55, a GPCR activated by lysophosphatidylinositol, an activity-dependent lipid messenger, readjusting the synaptic excitatory-inhibitory ratio.”

https://pubmed.ncbi.nlm.nih.gov/40048808/

https://molpharm.aspetjournals.org/article/S0026-895X(25)00003-3/fulltext

The use of cannabidiol in patients with Lennox-Gastaut syndrome and Dravet syndrome in the UK Early Access Program: A retrospective chart review study

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“Purpose: To evaluate clinical outcomes from the UK Early Access Program in patients aged 2-17 years with Lennox-Gastaut syndrome (LGS) or Dravet syndrome (DS) treated with plant-derived highly purified cannabidiol (CBD; Epidyolex®; 100 mg/mL oral solution).

Methods: Retrospective chart review of data collected from baseline (1 month before CBD treatment initiation) until 12 months’ treatment, CBD discontinuation, death, or loss to follow up.

Results: At baseline, all 26 patients enrolled (LGS, n = 17; DS, n = 9; male, 73 %; mean [range] age, 11.8 [3.0-17.0] years) experienced motor seizures; 92 % were taking ≥ 1 antiseizure medication. Median (IQR) CBD dosage at 6 months (6 M; n = 12) was 6.0 (2.7) mg/kg/day, and 12 months (12 M; n = 9) 7.3 (2.1) mg/kg/day. Median (IQR) percentage change from baseline for motor seizures was – 56.7 % (60.7) at 6 M (n = 20), and – 60.0 % (53.3) at 12 M (n = 15). Patients experiencing ≥ 50 % and ≥ 75 % reduction in motor seizures were 13/20 (65 %) and 5/20 (25 %) at 6 M, respectively, and 10/15 (67 %) and 6/15 (40 %) at 12 M, respectively. Mean (SD) motor seizure-free days/month were 1.5 (4.3) at baseline (n = 24, missing data n = 2), 2.4 (6.3) at 6 M (n = 18), and 2.7 (5.5) at 12 M (n = 15). At 12 M, CBD retention for patients with follow-up data was 14/19 (74 %), whilst 7/26 (27 %) were lost to follow up. The number of patients reporting ≥ 1 adverse event of special interest (most common: gastrointestinal) was 14/20 (70 %) and 8/15 (53 %) at 6 M and 12 M, respectively.

Conclusion: Results demonstrate a reduction in motor seizures and a safety profile consistent with previous studies.”

https://pubmed.ncbi.nlm.nih.gov/39898301/

“Results on CBD effectiveness and safety are consistent with previous studies.”

https://www.sciencedirect.com/science/article/pii/S2589986424000881?via%3Dihub

The use of cannabidiol as adjunctive therapy in adult patients with drug-resistant epilepsy: a systematic review and meta-analysis

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“Background: Highly purified cannabidiol (CBD), recently approved for various neurological disorders, is explored as a potential therapeutic avenue for drug-resistant epilepsy (DRE) among adult people with epilepsy (PWE) in this systematic review and meta-analysis.

Objectives: To conduct an extensive literature review and meta-analysis of CBD use for DRE in adult PWE.

Design: Systematic review and meta-analysis.

Data sources and methods: We conducted a systematic review of the literature according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and two electronic resources; we searched Ovid MEDLINE and Scopus using appropriate keywords until August 2023. Data were presented as standardized mean difference (SMD) and odds ratio with confidence interval (CI) via random effect. We appraised the risk of bias of the included studies using the Joanna Briggs Institute critical appraisal tool while their strength of evidence with the Oxford Centre for Evidence-Based Medicine (OCEBM) and Grading of Recommendations Assessment Development and Education (GRADE) Levels of Evidence.

Results: We identified 16 studies, 3 of which were randomized controlled trials and 3 prospective cohort studies, while the rest were expanded access programs, deriving a total of 668 participants receiving CBD for seizure control. CBD was used concomitantly with antiseizure medications in all studies. There was a statistically significant seizure reduction in the group receiving CBD therapy compared to the placebo group (SMD: -1.50, 95% CI (-3.47, 0.47), p < 0.01).

Conclusion: The evidence on CBD use in adult patients with DRE demonstrates a moderate level of certainty according to GRADE level and OCEBM level 2. Further prospective studies involving multiple centers are encouraged to study both the efficacy and safety of CBD in adult patients with DRE.”

https://pubmed.ncbi.nlm.nih.gov/39882324/

“Our review has shown that CBD was efficacious as an adjunctive therapy in seizure reduction in adult patients with DRE.”

https://journals.sagepub.com/doi/10.1177/17562864251313914

Update on Cannabidiol in Drug-Resistant Epilepsy

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“Cannabidiol (CBD) has arisen as a promising therapeutic option for children with drug-resistant epilepsy (DRE). CBD has received regulatory nod from different regulatory authorities in the United States, Europe, and India for children with DRE particularly, Dravet syndrome (DS), Lennox Gastaut syndrome (LGS), and Tuberous sclerosis complex (TSC).

Recent clinical trials and observational studies highlight the potential of CBD to lower seizure frequency and provide better quality of life in children affected by these disorders.

The safety profile is generally favorable with minor common adverse events such as somnolence, diarrhea, and gastrointestinal issues. Furthermore, the expense associated with CBD remains a notable concern, especially in low- and middle-income countries such as India, where access to this promising treatment may be constrained. This draws attention to the cost-effective perspective of CBD.

This review aims to explore the pharmacological properties of CBD, its mechanisms of action, and the clinical evidence supporting its use in various pediatric epilepsies, including LGS, DS, and TSC. Additionally, this review sheds light on the current regulatory landscape in India where CBD use is still in its nascent stages, and discusses the challenges and opportunities for integrating CBD into clinical practice.”

https://pubmed.ncbi.nlm.nih.gov/39585547/

https://link.springer.com/article/10.1007/s12098-024-05337-1

Cannabidiol Treatment for Adult Patients with Drug-Resistant Epilepsies: A Real-World Study in a Tertiary Center

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“Background and purpose: Around 30% of patients with epilepsy show drug-resistant epilepsy (DRE). While cannabidiol has demonstrated efficacy as an adjunctive treatment in Dravet syndrome (DS), Lennox-Gastaut Syndrome (LGS), and epilepsy related to tuberous sclerosis complex (TSC), its more global effectiveness in adult patients with DRE apart from these three specific contexts needs to be clarified.

Methods: We conducted a retrospective study at the epilepsy unit of Pitié Salpêtrière Hospital. Patients initiating pharmaceutical cannabidiol treatment and followed for at least 1 year were included. Patients were categorized into “authorized” (LGS, DS, or TSC) and “off-label” groups. Cannabidiol effectiveness and tolerance were compared between groups, and characteristics of responders (patients with >50% reduction in seizure frequency) in the off-label group were examined.

Results: Ninety-one patients, followed by a median duration of 24 months, were included. A total of 35.2% of the patients were in the authorized group. No significant differences were observed in responder rates between groups (31.3% vs. 35.6%, p = 0.85) and retention rates at 1 year (75.0% vs. 74.6%, p = 0.97). Sleepiness was more commonly reported in the authorized group (50.0% vs. 22.0%, p = 0.01), with no other significant differences. Among off-label patients (n = 59), clobazam co-prescription was more prevalent in responders (71.4% vs. 28.9%, p = 0.002).

Conclusion: Our findings suggest that cannabidiol may benefit all adult patients with DRE, particularly those already receiving clobazam. Randomized controlled trials are warranted in off-label patients to validate these observational findings.”

https://pubmed.ncbi.nlm.nih.gov/39501537/

https://onlinelibrary.wiley.com/doi/10.1002/brb3.70122