Cannabidiol in patients with Lennox-Gastaut syndrome: Interim analysis of an open-label extension study

A Cost-Utility Analysis of Add-On Cannabidiol Versus Usual Care Alone for the Treatment of Seizures Associated with Tuberous Sclerosis Complex in England and Wales

OBJECTIVES

The aim of this study was to evaluate the cost effectiveness of plant-derived highly purified cannabidiol (Epidyolex® in the UK; 100 mg/mL oral solution) as an add-on treatment to usual care for the management of treatment-refractory seizures associated with tuberous sclerosis complex (TSC) in patients aged ≥ 2 years.

METHODS

A cohort-based model was developed using a National Health Service perspective and lifetime horizon. Health states were based on weekly seizure frequency and seizure-free days, utilizing patient-level data from the GWPCARE6 trial (ClinicalTrials.gov identifier: NCT02544763). Two independent regression models were applied to individual patient-level data to predict seizure-free days and seizure frequency. Healthcare resource utilization data were sourced from a Delphi panel, and patient and caregiver health-related quality of life values were elicited using vignettes valued by the general public. Outcomes relating to TSC-associated neuropsychiatric disorders were modeled with costs and quality-adjusted life-years sourced from published literature.

RESULTS

In the base case, compared with usual care alone, 12 mg/kg/day cannabidiol was associated with an incremental cost-effectiveness ratio (ICER) of £23,797. The National Institute for Health and Care Excellence disease severity modifier reduced the ICER to £19,831. Probabilities of cost effectiveness at willingness-to-pay thresholds of £20,000 and £30,000 were 30% and 52%, respectively, for the base case and 39% and 66%, respectively, for the disease severity modifier. Results were robust to sensitivity and scenario analyses.

CONCLUSIONS

At 12 mg/kg/day and an ICER threshold of £20,000-£30,000, we provide evidence for the cost effectiveness of add-on cannabidiol treatment for patients with TSC-associated seizures aged ≥ 2 years who are refractory to current treatment.

Decoding epilepsy treatment: A comparative evaluation contrasting cannabidiol pharmacokinetics in adult and paediatric populations

Epilepsy is a neurological disorder characterized by overstimulation of neurotransmitters and uncontrolled seizures. Current medications for epilepsy result in adverse effects or insufficient seizure control, highlighting the necessity to develop alternative therapies. Cannabidiol (CBD), derived from cannabis plants, has been popularly explored as an alternative. CBD is shown to have anti-convulsivatng and muscle-relaxing properties, which have been used in patients with epilepsy with promising results. Current research explores varying dosages in either adult or paediatric patients, with little or no comparison between the two populations. In this review, we aim at consolidating this data and comparing the effect and pharmacokinetic properties of CBD across these two patient populations. When comparing the absorption, there was insufficient data to show differences between paediatric and adult patients. Similarly, limited information was available in comparing the distribution of CBD, but a higher volume of distribution was found in the paediatric population. From the metabolism perspective, the paediatric population had a greater success rate when treated with the drug compared to the adult population. In the elimination, there were no clear distinctions in the clearance rate between the two populations. The drug's half-life was highly variable in both populations, with paediatrics having a lower range than adults. In summary, the paediatric population had a more significant reduction in the severity of seizures compared to the adult population upon CBD treatment. The complexity in which CBD operates highlights the need for further studies of the compound to further understand why differences occur between these two populations.

Subtype-specific modulation of human KV 7 channels by the anticonvulsant cannabidiol through a lipid-exposed pore-domain site

BACKGROUND AND PURPOSE

Cannabidiol (CBD) is used clinically as an anticonvulsant. Its precise mechanism of action has remained unclear. CBD was recently demonstrated to enhance the activity of the neuronal KV 7.2/7.3 channel, which may be one important contributor to CBD anticonvulsant effect. Curiously, CBD inhibits the closely related cardiac KV 7.1/KCNE1 channel. Whether and how CBD affects other KV 7 subtypes remains uninvestigated and the CBD interaction sites mediating these diverse effects remain unknown.

EXPERIMENTAL APPROACH

Here, we used electrophysiology, molecular dynamics simulations, molecular docking and site-directed mutagenesis to address these questions.

KEY RESULTS

We found that CBD modulates the activity of all human KV 7 subtypes and that the effects are subtype dependent. CBD enhanced the activity of KV 7.2-7.5 subtypes, seen as a V50 shift towards more negative voltages or increased maximum conductance. In contrast, CBD inhibited the KV 7.1 and KV 7.1/KCNE1 channels, seen as a V50 shift towards more positive voltages and reduced conductance. In KV 7.2 and KV 7.4, we propose a CBD interaction site at the subunit interface in the pore domain that overlaps with the interaction site of other compounds, notably the anticonvulsant retigabine. However, CBD relies on other residues for its effects than the conserved tryptophan that is critical for retigabine effects. We propose a similar, though not identical CBD site in KV 7.1, with a non-conserved phenylalanine being important.

CONCLUSIONS AND IMPLICATIONS

We identify novel targets of CBD, contributing to a better understanding of CBD clinical effects and provide mechanistic insights into how CBD modulates different KV 7 subtypes.

Assessing Liver Effects of Cannabidiol and Valproate Alone and in Combination Using Quantitative Systems Toxicology

In clinical trials of cannabidiol (CBD) for the treatment of seizures in patients with Dravet syndrome, Lennox-Gastaut syndrome, and tuberous sclerosis complex, elevations in serum alanine aminotransferase (ALT) > 3× the upper limit of normal were observed in some patents, but the incidence was much greater in patients who were receiving treatment with valproate (VPA) before starting CBD. To explore potential mechanisms underlying this interaction, we used DILIsym, a quantitative systems toxicology model, to predict ALT elevations in a simulated human population treated with CBD alone, VPA alone, and when CBD dosing was starting during treatment with VPA. We gathered in vitro data assessing the potential for CBD, the two major CBD metabolites, and VPA to cause hepatotoxicity via inhibition of bile acid transporters, mitochondrial dysfunction, and production of reactive oxygen species (ROS). Physiologically-based pharmacokinetic models for CBD and VPA were used to predict liver exposure. DILIsym simulations predicted dose-dependent ALT elevations from CBD treatment and this was predominantly driven by ROS production from the parent molecule. DILIsym also predicted VPA treatment to cause ALT elevations which were transient when mitochondrial biogenesis was incorporated into the model. Contrary to the clinical experience, simulation of 2 weeks treatment with VPA prior to introduction of CBD treatment did not predict an increase of the incidence of ALT elevations relative to CBD treatment alone. We conclude that the marked increased incidence of CBD-associated ALT elevations in patients already receiving VPA is unlikely to involve the three major mechanisms of direct hepatotoxicity.

The new International League Against Epilepsy (ILAE) definition of Lennox-Gastaut syndrome: Practical implications and limitations

PURPOSE

There are three major changes in the new definition of Lennox-Gastaut syndrome (LGS) compared with the traditional definition: (1) onset prior to 18 years, (2) must include tonic seizure, (3) generalized slow spike-waves (SSW) and (instead of or) generalized paroxysmal fast activity (GPFA) on electroencephalography (EEG). We investigated the practical implications and potential limitations of the new LGS definition based on a large cohort of patients in an exploratory study.

METHODS

This was a retrospective database study. All patients with an electro-clinical diagnosis of LGS (based on its traditional definition) at the outpatient epilepsy clinic at Shiraz University of Medical Sciences, Shiraz, Iran were included (from 2008 until 2020). Patients were reclassified based on the new definition of LGS.

RESULTS

In total, 3737 patients were registered. Based on its traditional definition, 300 patients were diagnosed as having LGS. According to the new definition of LGS, only 96 patients (32% of the traditional cohort) had LGS. One patient, who had other criteria, had and age at onset of 21 years; 29 patients (9.7%) did not have SSW in their EEGs; 139 people (46.3%) did not have GPFA in their EEGs; and, 111 patients (37%) did not report having tonic seizures.

CONCLUSION

The new International League Against Epilepsy (ILAE) definition of LGS has some important practical implications and limitations. Before reinforcing and making this new definition compulsory in future research and clinical practice, more work is needed to enlighten various aspects of such changes in the definition of this epilepsy syndrome.

Pharmacological diversity amongst approved and emerging antiseizure medications for the treatment of developmental and epileptic encephalopathies

Developmental and epileptic encephalopathies (DEEs) are rare neurodevelopmental disorders characterised by early-onset and often intractable seizures and developmental delay/regression, and include Dravet syndrome and Lennox-Gastaut syndrome (LGS). Rufinamide, fenfluramine, stiripentol, cannabidiol and ganaxolone are antiseizure medications (ASMs) with diverse mechanisms of action that have been approved for treating specific DEEs. Rufinamide is thought to suppress neuronal hyperexcitability by preventing the functional recycling of voltage-gated sodium channels from the inactivated to resting state. It is licensed for adjunctive treatment of seizures associated with LGS. Fenfluramine increases extracellular serotonin levels and may reduce seizures via activation of specific serotonin receptors and positive modulation of the sigma-1 receptor. Fenfluramine is licensed for adjunctive treatment of seizures associated with Dravet syndrome and LGS. Stiripentol is a positive allosteric modulator of type-A gamma-aminobutyric acid (GABAA) receptors. As a broad-spectrum inhibitor of cytochrome P450 enzymes, its antiseizure effects may additionally arise through pharmacokinetic interactions with co-administered ASMs. Stiripentol is licensed for treating seizures associated with Dravet syndrome in patients taking clobazam and/or valproate. The mechanism(s) of action of cannabidiol remains largely unclear although multiple targets have been proposed, including transient receptor potential vanilloid 1, G protein-coupled receptor 55 and equilibrative nucleoside transporter 1. Cannabidiol is licensed as adjunctive treatment in conjunction with clobazam for seizures associated with Dravet syndrome and LGS, and as adjunctive treatment of seizures associated with tuberous sclerosis complex. Like stiripentol, ganaxolone is a positive allosteric modulator at GABAA receptors. It has recently been licensed in the USA for the treatment of seizures associated with cyclin-dependent kinase-like 5 deficiency disorder. Greater understanding of the causes of DEEs has driven research into the potential use of other novel and repurposed agents. Putative ASMs currently in clinical development for use in DEEs include soticlestat, carisbamate, verapamil, radiprodil, clemizole and lorcaserin.

Cannabidiol inhibits Nav channels through two distinct binding sites

Cannabidiol (CBD), a major non-psychoactive phytocannabinoid in cannabis, is an effective treatment for some forms of epilepsy and pain. At high concentrations, CBD interacts with a huge variety of proteins, but which targets are most relevant for clinical actions is still unclear. Here we show that CBD interacts with Nav1.7 channels at sub-micromolar concentrations in a state-dependent manner. Electrophysiological experiments show that CBD binds to the inactivated state of Nav1.7 channels with a dissociation constant of about 50 nM. The cryo-EM structure of CBD bound to Nav1.7 channels reveals two distinct binding sites. One is in the IV-I fenestration near the upper pore. The other binding site is directly next to the inactivated "wedged" position of the Ile/Phe/Met (IFM) motif on the short linker between repeats III and IV, which mediates fast inactivation. Consistent with producing a direct stabilization of the inactivated state, mutating residues in this binding site greatly reduced state-dependent binding of CBD. The identification of this binding site may enable design of compounds with improved properties compared to CBD itself.

Disease-modifying effects of cannabidiol, β-caryophyllene and their combination in Syn1-Cre/Scn1aWT/A1783V mice, a preclinical model of Dravet syndrome

Cannabidiol (CBD) has been recently approved as an antiseizure agent in Dravet Syndrome (DS), a pediatric epileptic encephalopathy, but CBD could also be active against associated comorbidities. Such associated comorbidities were also attenuated by the sesquiterpene β-caryophyllene (BCP). Here, we have compared the efficacy of both compounds and further initiated the analysis of a possible additive effect between both compounds in relation with these comorbidities using two experimental approaches. The first experiment was aimed at comparing the benefits of CBD and BCP, including their combination in conditional knock-in Scn1a-A1783V mice, an experimental model of DS, treated since the postnatal day 10th to 24th. As expected, DS mice showed impairment in limb clasping, delay in the appearance of hindlimb grasp reflex and additional behavioural disturbances (e.g., hyperactivity, cognitive deterioration, social interaction deficits). This behavioural impairment was associated with marked astroglial and microglial reactivities in the prefrontal cortex and the hippocampal dentate gyrus. BCP and CBD administered alone were both able to partially attenuate the behavioural disturbances and the glial reactivities, with apparently greater efficacy against glial reactivities obtained with BCP, whereas superior effects in a few specific parameters were obtained when both compounds were combined. In the second experiment, we investigated this additive effect in cultured BV2 cells treated with BCP and/or CBD and stimulated with LPS. As expected, addition of LPS induced a marked increase in several inflammation-related markers (e.g., TLR4, COX-2, iNOS, catalase, TNF-α, IL-1β), as well as elevated Iba-1 immunostaining. Treatment with BCP or CBD attenuated these elevations, but, again and in general, superior results were obtained when both cannabinoids were combined. In conclusion, our results support the interest to continue investigating the combination of BCP and CBD to improve the therapeutic management of DS in relation with their disease-modifying properties.

Proposed anti-seizure medication combinations with rufinamide in the treatment of Lennox-Gastaut syndrome: Narrative review and expert opinion

Lennox-Gastaut syndrome (LGS) is a severe, chronic, complex form of early childhood-onset epilepsy characterized by multiple seizure types, generalized slow (≤2.5 Hz) spike-and-wave activity and other electroencephalography abnormalities, and cognitive impairment. A key treatment goal is early seizure control, and several anti-seizure medications (ASMs) are available. Due to the low success rate in achieving seizure control with monotherapy and an absence of efficacy data supporting any particular combination of ASMs for treating LGS, a rational approach to selection of appropriate polytherapy should be applied to maximize benefit to patients. Such "rational polytherapy" involves consideration of factors including safety (including boxed warnings), potential drug-drug interactions, and complementary mechanisms of action. Based on the authors' clinical experience, rufinamide offers a well-considered first adjunctive therapy for LGS, particularly in combination with clobazam and other newer agents for LGS, and may be particularly useful for reducing the frequency of tonic-atonic seizures associated with LGS.

Current and emerging pharmacotherapy for the treatment of Lennox-Gastaut syndrome

INTRODUCTION

Lennox-Gastaut syndrome (LGS) is a severe childhood-onset epileptic encephalopathy, characterized by multiple seizure types, generalized slow spike-and-wave complexes in the EEG, and cognitive impairment. Seizures in LGS are typically resistant to treatment with antiseizure medications (ASMs). Tonic/atonic ('drop') seizures are of particular concern, due to their liability to cause physical injury.

AREAS COVERED

We summarize evidence for current and emerging ASMs for the treatment of seizures in LGS. The review focuses on findings from randomized, double-blind, placebo-controlled trials (RDBCTs). For ASMs for which no double-blind trials were identified, lower quality evidence was considered. Novel pharmacological agents currently undergoing investigation for the treatment of LGS are also briefly discussed.

EXPERT OPINION

Evidence from RDBCTs supports the use of cannabidiol, clobazam, felbamate, fenfluramine, lamotrigine, rufinamide, and topiramate as adjunct treatments for drop seizures. Percentage decreases in drop seizure frequency ranged from 68.3% with high-dose clobazam to 14.8% with topiramate. Valproate continues to be considered the first-line treatment, despite the absence of RDBCTs specifically in LGS. Most individuals with LGS will require treatment with multiple ASMs. Treatment decisions should be individualized and take into account adverse effects, comorbidities, general quality of life, and drug interactions, as well as individual efficacy.

Long-term efficacy and safety of cannabidiol in patients with treatment-resistant epilepsies: Four-year results from the expanded access program

OBJECTIVE

Cannabidiol (CBD) expanded access program, initiated in 2014, provided add-on CBD to patients with treatment-resistant epilepsies (TREs) at 35 US epilepsy centers. Prior publications reported results through December 2016; herein, we present efficacy and safety results through January 2019.

METHODS

Patients received plant-derived highly purified CBD (Epidiolex®; 100 mg/ml oral solution), increasing from 2 to 10 mg/kg/day to tolerance or maximum 25-50 mg/kg/day dose, depending on the study site. Efficacy endpoints included percentage change from baseline in median monthly convulsive and total seizure frequency and ≥50%, ≥75%, and 100% responder rates across 12-week visit windows for up to 192 weeks. Adverse events (AEs) were documented at each visit.

RESULTS

Of 892 patients in the safety analysis set, 322 (36%) withdrew; lack of efficacy (19%) and AEs (7%) were the most commonly reported primary reasons for withdrawal. Median (range) age was 11.8 years (range = 0-74.5), and patients were taking a median of three (range = 0-10) antiseizure medications (ASMs) at baseline; the most common ASMs were clobazam (47%), levetiracetam (34%), and valproate (28%). Median top CBD dose was 25 mg/kg/day; median exposure duration was 694 days. Median percentage reduction from baseline ranged 50%-67% for convulsive seizures and 46%-66% for total seizures. Convulsive seizure responder rates (≥50%, ≥75%, and 100% reduction) ranged 51%-59%, 33%-42%, and 11%-17% of patients across visit windows, respectively. AEs were reported in 88% of patients and serious AEs in 41%; 8% withdrew because of an AE. There were 20 deaths during the study deemed unrelated to treatment by the investigator. The most common AEs (≥20% of patients) were diarrhea (33%), seizure (24%), and somnolence (23%).

SIGNIFICANCE

Add-on CBD was associated with sustained seizure reduction up to 192 weeks with an acceptable safety profile and can be used for long-term treatment of TREs.

Update on Cannabidiol Clinical Toxicity and Adverse Effects: A Systematic Review

BACKGROUND

Compelling evidence from preclinical and clinical studies supports the therapeutic role of cannabidiol (CBD) in several medical disorders. We reviewed the scientific evidence on CBD-related toxicity and adverse events (AEs) in 2019, at the beginning of the spike in clinical studies involving CBD. However, CBD safety remained uncertain.

OBJECTIVE

With the benefit of hindsight, we aimed to provide an update on CBD-related toxicity and AEs in humans.

METHODS

A systematic literature search was conducted following PRISMA guidelines. PubMed, Cochrane, and Embase were accessed in October 2022 to identify clinical studies mentioning CBDrelated toxicity/AEs from February 2019 to September 2022. Study design, population characteristics, CBD doses, treatment duration, co-medications, and AEs were compiled.

RESULTS

A total of 51 reports were included. Most studies investigated CBD efficacy and safety in neurological conditions, such as treatment-resistant epilepsies, although a growing number of studies are focusing on specific psychopathological conditions, such as substance use disorders, chronic psychosis, and anxiety. Most studies report mild or moderate severity of AEs. The most common AEs are diarrhea, somnolence, sedation, and upper respiratory disturbances. Few serious AEs have been reported, especially when CBD is co-administered with other classes of drugs, such as clobazam and valproate.

CONCLUSION

Clinical data suggest that CBD is well tolerated and associated with few serious AEs at therapeutic doses both in children and adults. However, interactions with other medications should be monitored carefully. Additional data are needed to investigate CBD's long-term efficacy and safety, and CBD use in medical conditions other than epilepsy syndromes.

Advances and Challenges of Cannabidiol as an Anti-Seizure Strategy: Preclinical Evidence

The use of Cannabis for medicinal purposes has been documented since ancient times, where one of its principal cannabinoids extracted from Cannabis sativa, cannabidiol (CBD), has emerged over the last few years as a promising molecule with anti-seizure potential. Here, we present an overview of recent literature pointing out CBD's pharmacological profile (solubility, metabolism, drug-drug interactions, etc.,), CBD's interactions with multiple molecular targets as well as advances in preclinical research concerning its anti-seizure effect on both acute seizure models and chronic models of epilepsy. We also highlight the recent attention that has been given to other natural cannabinoids and to synthetic derivatives of CBD as possible compounds with therapeutic anti-seizure potential. All the scientific research reviewed here encourages to continue to investigate the probable therapeutic efficacy of CBD and its related compounds not only in epilepsy but also and specially in drug-resistant epilepsy, since there is a dire need for new and effective drugs to treat this disease.

A Pilot Study on the Use of Low Doses of CBD to Control Seizures in Rare and Severe Forms of Drug-Resistant Epilepsy

Due to its anticonvulsant properties, cannabidiol can be supportive as an adjuvant therapy in the management of drug resistant epilepsy. This retrospective observational study evaluates the intensity and frequency of the seizures of patients with drug-resistant epilepsy that have been treated with antiepileptic medication associated with CBD in low doses for at least 12 months. Thirty-four patients were included in the study. The most frequent diagnosis of epilepsy was focal symptomatic epilepsy and Lennox−Gastaut syndrome (35.2%). During the follow-up, there was a statistically significant decrease in the seizure frequency (t student p < 0.001). A high proportion of patients, 16, concluded the study with a total control of the seizures reaching a 100% improvement, 12 reported ≥ 75% improvement, 3 ≥ 50%, and 2 ≥ 25%; only 1 patient had an improvement of less than 25%. This is the first Latin American study that demonstrates that long-term CBD added to the usual drugs significantly reduces the frequency, duration, and type of seizures in the different etiologies of epilepsy, being especially effective on the seizures that are the most incapacitating, improving the quality of life of the individual and their family.

Cannabidiol in canine epilepsy

The anticonvulsant effect of cannabidiol (CBD), which has been confirmed by findings from animal models and human trials, has attracted the interest of veterinary practitioners and dog owners. Moreover, social media and public pressure has sparked a renewed awareness of cannabinoids, which have been used for epilepsy since ancient times. Unfortunately, at this moment veterinarians and veterinary neurologists have difficulty prescribing cannabinoids because of the paucity of sound scientific studies. Pharmacokinetic studies in dogs have demonstrated a low oral bioavailability of CBD and a high first-pass effect through the liver. Administering CBD in oil-based formulations and/or with food has been shown to enhance the bioavailability in dogs, rats and humans. Tolerability studies in healthy dogs and dogs with epilepsy have demonstrated that CBD was safe and well tolerated with only mild to moderate adverse effects. In this context, it should be noted that the quality of available CBD varies widely, underscoring the importance of pharmaceutical quality and its control. One clinical trial in dogs with drug-resistant idiopathic epilepsy failed to confirm a difference in response rates between the CBD group and the placebo group, while in another cross-over trial a ≥ 50 % reduction in epileptic seizure frequency was found in six of 14 dogs in the treatment phase, a reduction that was not observed during the placebo phase. Based on the current state of knowledge it is not possible to provide clear-cut recommendations for the use of CBD in canine epilepsy. Randomized controlled canine trials with large sample sizes are needed to determine the range of therapeutic plasma concentrations, develop evidence-based dosing regimens, determine the efficacy of cannabidiol in drug-refractory epilepsy, and explore potential associations between treatment effects and different etiologies, epilepsy types, and drug combinations.

Medical cannabis for the treatment of comorbid symptoms in children with autism spectrum disorder: An interim analysis of biochemical safety

Background: Autistic Spectrum Disorder (ASD) is a common neurodevelopmental disorder and no effective treatment for the core symptoms is currently available. The present study is part of a larger clinical trial assessing the effects of cannabis oil on autism co-morbidities.

Objectives: The aim of the present study was to assess the safety of a CBD-rich oil treatment in children and adolescents with ASD.

Methods: Data from 59 children and young adults (ages 5–25 years) from a single-arm, ongoing, prospective, open-label, one center, phase III study was analyzed. Participants received the Nitzan Spectrum® Oil, with cannabis extracts infused in medium chain triglyceride (MCT) oil with a cannabidiol:THC ratio of 20:1, for 6 months. Blood analysis was performed before treatment initiation, and after 3 months. Complete blood count, glucose, urea, creatinine, electrolytes, liver enzymes (AST, ALT, gamma glutamyl transferase), bilirubin, lipid profile, TSH, FT4, thyroid antibodies, prolactin, and testosterone measurements were performed at baseline, prior to starting treatment and at study midpoint, after 3 months of treatment.

Results: 59 children (85% male and 15% female) were followed for 18 ± 8 weeks (mean ±SD). The mean total daily dose was 7.88 ± 4.24 mg/kg body weight. No clinically significant differences were found in any of the analytes between baseline and 3 months follow up. Lactate dehydrogenase was significantly higher before treatment (505.36 ± 95.1 IU/l) as compared to its level after 3 months of treatment (470.55 ± 84.22 IU/L) (p = 0.003). FT4 was significantly higher after 3 months of treatment (15.54 ± 1.9) as compared to its level before treatment (15.07 ± 1.88) (p = 0.03), as was TSH [(2.34 ± 1.17) and (2.05 ± 1.02)] before and after 3 months of treatment, respectively (p = 0.01). However, all these values were within normal range. A comparison of the group with additional medications (n = 14) to those who received solely medical cannabis (n = 45) showed no difference in biochemical analysis, including liver enzymes, which remained stable, except for change in potassium level which was significantly higher in the group that did not receive additional medications (0.04 ± 0.37) compared to the group receiving concomitant drug therapy (-0.2 ± 0.33) (p = 0.04). A comparison of patients who received a high dose of the cannabis oil (upper quartile-16 patients), with those receiving a low dose (lower quartile—14 patients) showed no significant difference between the two groups, except for the mean change of total protein, which was significantly higher among patients receiving high dose of CBD (0.19 ± 2.74) compared to those receiving a low dose of CBD (1.71 ± 2.46 (p = 0.01), and mean change in number of platelets, that was significantly lower among patients who received high dose of CBD (13.46 ± 31.38) as compared to those who received low dose of CBD (29.64 ± 26.2) (p = 0.0007). However, both of these changes lack clinical significance.

Conclusion: CBD-rich cannabis oil (CBD: THC 20:1), appears to have a good safety profile. Long-term monitoring with a larger number of participants is warranted.

Quantitative electroencephalographic analysis as a potential biomarker of response to treatment with cannabidiol

PURPOSE

Pharmaceutical grade cannabidiol (CBD) is one of the newest anti-seizure medications for refractory epilepsy, and the effects of CBD on EEG have not been fully described.

METHODS

Patients enrolled in a CBD expanded access study had EEGs prior to and 12 weeks after initiation of CBD treatment for their refractory epilepsy. In addition to evaluating the clinical EEG reports, a nonbiased quantitative EEG (qEEG) analysis of background EEG was performed to determine whether consistent changes occur in the EEG in response to administration of CBD.

RESULTS

No significant qualitative changes were seen, nor changes in quantitative markers of EEG amplitude (RMS amplitude, standard deviation of the amplitude, skewness, or kurtosis), frequency (relative delta, theta, or alpha power), Spearman correlation, or coherence between brain regions. However, relative beta power and 1/f slope, a measure of signal noise increased with the addition of CBD. When patients were separated into responders and nonresponders based on seizure reduction with CBD, responders also had decreased Spearman correlation between the frontopolar and occipital regions after addition of CBD, suggesting that responders may have quantitatively improved EEG background organization after CBD initiation. The differences in beta and 1/f slope were also seen more robustly in CBD responders compared with nonresponders after CBD initiation. These differences disappeared when analyzing only patients not taking benzodiazepines, suggesting that the effect of CBD on seizures was related to the ability of the brain to further increase beta in response to CBD in patients already taking benzodiazepines. We noted that even before initiation of CBD, 1/f slope was also significantly different in responders compared to nonresponders. Therefore, to explore the baseline EEG in responders and nonresponders, we utilized a variable selection procedure to identify baseline EEG features that could predict whether a patient's seizures would improve with CBD. In the optimal multivariable logistic model, baseline coherence, Spearman correlation, and patient sex jointly predicted whether a patient in this cohort would respond to CBD (defined as a seizure reduction of 40% or greater) with 74% accuracy. This model performed less well on a data set of reduced duration and variability, highlighting the importance of real-world testing of any clinically relevant model.

CONCLUSION

These results suggest that there are subtle changes in certain metrics detected by qEEG even at baseline that may not be perceived during qualitative EEG analysis and that could be used in the future as a biomarker to predict a patient's clinical response to CBD administration. Development of such a predictive EEG biomarker, especially before the initiation of a medication trial, could reduce unnecessary ASM exposure and improve outcomes for patients with epilepsy facing new medication selection.

Impact of Antiseizure Medications on Appetite and Weight in Children

There are numerous potential factors that may affect growth in children with epilepsy, and these must be evaluated in any child with appetite and weight concerns. Antiseizure medications (ASMs) have potential adverse effects, and many may affect appetite, thus impacting normal growth and weight gain. The aim of this review is to focus on the impact of both epilepsy and ASMs on appetite and weight in children. We systematically reviewed studies using Medline assessing the impact of ASMs on appetite and weight in children. Eligible studies included randomized controlled trials and open-label studies (open-label extension and interventional) that targeted or included the pediatric population (0-18 years of age). Each study was classified using the American Academy of Neurology (AAN) Classification of Evidence for Therapeutic Studies, and the level of evidence for impact on appetite and weight in children was graded. ASMs associated with decreased appetite and/or weight loss include fenfluramine, topiramate, zonisamide, felbamate, rufinamide, stiripentol, cannabidiol, brivaracetam and ethosuximide; ASMs with minimal impact on weight and appetite in children include oxcarbazepine, eslicarbazepine, lamotrigine, levetiracetam, lacosamide, carbamazepine, vigabatrin and clobazam. The ASM most robustly associated with increased appetite and/or weight gain is valproic acid; however, both pregabalin and perampanel may also lead to modest weight gain or increased appetite in children. Certain ASMs may impact both appetite and weight, which may lead to increased morbidity of the underlying disease and impaired adherence to the treatment regimen.

Adjunctive Transdermal Cannabidiol for Adults With Focal Epilepsy: A Randomized Clinical Trial

Importance

Cannabidiol has shown efficacy in randomized clinical trials for drug-resistant epilepsy in specific syndromes that predominantly affect children. However, high-level evidence for the efficacy and safety of cannabidiol in the most common form of drug-resistant epilepsy in adults, focal epilepsy, is lacking.

Objective

To investigate the efficacy, safety, and tolerability of transdermally administered cannabidiol in adults with drug-resistant focal epilepsy.

Design, Setting, and Participants

A randomized, double-blind, placebo-controlled, multicenter clinical trial at 14 epilepsy trial centers in Australia and New Zealand. Participants were adults with drug-resistant focal epilepsy receiving a stable regimen of up to 3 antiseizure medications. Data were analyzed from July 2017 to November 2018.

Interventions

Eligible participants were randomized (1:1:1) to 195-mg or 390-mg transdermal cannabidiol or placebo twice daily for 12 weeks, after which they could enroll in an open-label extension study for up to 2 years.

Main Outcomes and Measures

Seizure frequency was self-reported using a daily diary. The primary efficacy end point was the least squares mean difference in the log-transformed total seizure frequency per 28-day period, adjusted to a common baseline log seizure rate, during the 12-week treatment period.

Results

A total of 188 patients (45% male [85 patients] and 54.8% female [103 patients]) with a mean (SD) age of 39.2 (12.78) years were randomized, treated, and analyzed (195-mg cannabidiol, 63 participants; 390-mg cannabidiol, 62 participants; placebo, 63 participants). At week 12 of the double-blind period, there was no difference in seizure frequency between placebo (mean [SD] 2.49 [1.31] seizures per 28 days) and 195-mg cannabidiol (mean [SD] 2.51 [1.15] seizures per 28 days; least squares mean difference, 0.014; 95% CI, -0.175 to 0.203; P = .89) or 390-mg cannabidiol (mean [SD] 2.59 [1.12] seizures per 28 days; least squares mean difference, 0.096; 95% CI, -0.093 to 0.285; P = .32). By month 6 of the open-label extension, 115 patients (60.8%) achieved a seizure reduction of at least 50%. Treatment-emergent adverse events occurred in 50.4% (63 of 125 participants) of the cannabidiol group vs 41.3% (26 of 63 participants) in the placebo group, with a treatment difference of 9.1% (95% CI, -6.0% to 23.6%), and occurred at similar rates in the cannabidiol groups. Few participants discontinued (7% [14 of 188 participants]), and most (98% [171 of 174 participants]) continued into the open-label extension.

Conclusions and Relevance

Both doses of transdermal cannabidiol were well tolerated and safe. No significant difference in efficacy was observed between cannabidiol and placebo during the double-blind treatment period. The open-label extension demonstrated the long-term safety, tolerability, and acceptability of transdermal cannabidiol delivery.

Trial Registration

ACTRN12616000510448 (double-blind); ACTRN12616001455459 (open-label).

Safety and efficacy of cathodal transcranial direct current stimulation in patients with Lennox Gastaut Syndrome: An open-label, prospective, single-center, single-blinded, pilot study

PURPOSE

Lennox-Gastaut Syndrome (SLG) is a severe form of childhood refractory epilepsy. Only one pilot study has been conducted using cathodal transcranial direct current stimulation (c-tDCs; 2mAx30minx5days) in LGS with promising results (-99% seizure reduction at 5 days). Our aim was to explore and replicate the efficacy and safety of 10 daily sessions of c-tDCs in SLG.

METHODS

We conducted a one-blinded, single-center pilot clinical study of c-tDCs (2mAx 30 min x 10 days), applied over the highest amplitude or frequent epileptiform interictal discharges areas using scalp EEG recordings without changes in their treatments. The tDCS device used was Enobio EEG® (Neuroelectrics, Barcelona, Spain). The primary outcome was based on the seizure frequency using seizure diaries before, during 10 days of treatment, and then on a 4 and 8 weeks of follow-up. The rate of adverse events was recorded as a secondary outcome. Descriptive statistics and Wilcoxon signed-rank test were used RESULTS: Twenty-four patients were enrolled. The mean age was 10.1 ± 5.8 years old and 75% male. All the patients had severe mental retardation and abnormal neurological examinations. A significant median percentual seizure frequency reduction was found: 68.12% (p = 0.05) at 1 week, 68.12% (p = 0.002) in the second week. We found no significant reduction at 1 and 2 months; mainly tonic and atonic seizures were reduced significantly at all times. Only mild self-limited side effects were recorded mainly itching and erythema in the application zone CONCLUSION: Ten sessions of c-tDCs in combination with pharmacologic treatment in LGS is safe and appears to reduce significatively tonic and atonic seizure frequency at 2 months of follow-up.

Statement on safety of cannabidiol as a novel food: data gaps and uncertainties

The European Commission has determined that cannabidiol (CBD) can be considered as a novel food (NF), and currently, 19 applications are under assessment at EFSA. While assessing these, it has become clear that there are knowledge gaps that need to be addressed before a conclusion on the safety of CBD can be reached. Consequently, EFSA has issued this statement, summarising the state of knowledge on the safety of CBD consumption and highlighting areas where more data are needed. Literature searches for both animal and human studies have been conducted to identify safety concerns. Many human studies have been carried out with Epidyolex^®, a CBD drug authorised to treat refractory epilepsies. In the context of medical conditions, adverse effects are tolerated if the benefit outweighs the adverse effect. This is, however, not acceptable when considering CBD as a NF. Furthermore, most of the human data referred to in the CBD applications investigated the efficacy of Epidyolex (or CBD) at therapeutic doses. No NOAEL could be identified from these studies. Given the complexity and importance of CBD receptors and pathways, interactions need to be taken into account when considering CBD as a NF. The effects on drug metabolism need to be clarified. Toxicokinetics in different matrices, the half‐life and accumulation need to be examined. The effect of CBD on liver, gastrointestinal tract, endocrine system, nervous system and on psychological function needs to be clarified. Studies in animals show significant reproductive toxicity, and the extent to which this occurs in humans generally and in women of child‐bearing age specifically needs to be assessed. Considering the significant uncertainties and data gaps, the Panel concludes that the safety of CBD as a NF cannot currently be established.

Over the counter low-dose cannabidiol: A viewpoint from the ACRE Capacity Building Group

Amidst growing global acceptance of medicinal cannabinoids as a potential therapeutic interest in cannabidiol (CBD) is increasing. In Australia in 2020, a government inquiry examined the barriers that the public are experiencing in accessing medicinal cannabis. A number of recommendations to improve access were made. In response to these recommendations, the Australian therapeutics regulatory authority down-scheduled CBD from Prescription Only (Schedule 4) to Pharmacist Only (Schedule 3). As a group of early to mid-career researchers of the Australian Centre for Cannabinoid Clinical and Research Excellence (ACRE), we propose some considerations in relation to over-the-counter availability of CBD and opportunities to improve knowledge about its potential therapeutic benefits alongside its increased uptake.

Movement Disorders Secondary to Novel Antiseizure Medications in Pediatric Populations: A Systematic Review and Meta-analysis of Risk

Novel antiseizure medications are thought to be safer than their conventional counterparts, though no dedicated analysis of movement disorder risk among pediatric populations using novel antiseizure medications has been completed. We report a systematic review with meta-analysis describing the relationship between novel antiseizure medications and movement disorders in pediatrics.MEDLINE, EMBASE, and the World Health Organization's International Clinical Trials Registry Platform were searched up to October 2020 for randomized controlled trials investigating novel antiseizure medications in pediatric populations. Antiseizure medications included lacosamide, perampanel, eslicarbazepine, rufinamide, fenfluramine, cannabidiol, and brivaracetam. Outcomes were pooled using random effects models; risk difference (RD) and 95% confidence intervals (CIs) were calculated.Twenty-three studies were selected from 1690 nonredundant manuscripts (n = 1912 total). There was a significantly increased risk of movement disorders associated with perampanel (RD 0.07, 95% CI 0.01-0.13; n = 133), though only 1 relevant trial was found. No increased risk of movement disorders was found with other antiseizure medications.Our findings indicate most novel antiseizure medications are safe to use in pediatric populations with respect to movement disorders. However, findings were limited by quality of adverse event reporting.

Medical Cannabis in Pediatric Oncology: Friend or Foe?

The antineoplastic effects of cannabis have been known since 1975. Since the identification of the components of the endogenous cannabinoid system (ECS) in the 1990s, research into the potential of cannabinoids as medicine has exploded, including in anti-cancer research. However, nearly all of this research has been on adults. Physicians and governing bodies remain cautious in recommending the use of cannabis in children, since the ECS develops early in life and data about cannabis exposure in utero show negative outcomes. However, there exist many published cases of use of cannabis in children to treat pediatric epilepsy and chemotherapy-induced nausea and vomiting (CINV) that show both the safety and efficacy of cannabis in pediatric populations. Additionally, promising preclinical evidence showing that cannabis has anti-cancer effects on pediatric cancer warrants further investigation of cannabis' use in pediatric cancer patients, as well as other populations of pediatric patients. This review aims to examine the evidence regarding the potential clinical utility of cannabis as an anti-cancer treatment in children by summarizing what is currently known about uses of medical cannabis in children, particularly regarding its anti-cancer potential.

Cannabidiol activates neuronal Kv7 channels

Cannabidiol (CBD), a chemical found in the Cannabis sativa plant, is a clinically effective antiepileptic drug whose mechanism of action is unknown. Using a fluorescence-based thallium flux assay, we performed a large-scale screen and found enhancement of flux through heterologously expressed human Kv7.2/7.3 channels by CBD. Patch-clamp recordings showed that CBD acts at submicromolar concentrations to shift the voltage dependence of Kv7.2/7.3 channels in the hyperpolarizing direction, producing a dramatic enhancement of current at voltages near –50 mV. CBD enhanced native M-current in mouse superior cervical ganglion starting at concentrations of 30 nM and also enhanced M-current in rat hippocampal neurons. The potent enhancement of Kv2/7.3 channels by CBD may contribute to its effectiveness as an antiepileptic drug by reducing neuronal hyperexcitability.

Cannabidiol Increases Seizure Resistance and Improves Behavior in an Scn8a Mouse Model

Voltage-gated sodium channel genes are an important family of human epilepsy genes. De novo missense mutations in SCN8A (encoding Na_v1.6) are associated with a spectrum of clinical presentation, including multiple seizure types, movement disorders, intellectual disability, and behavioral abnormalities such as autism. Patients with SCN8A mutations are often treated with multiple antiepileptic drugs, the most common being sodium channel blockers. Cannabidiol (CBD) has been included as a component of treatment regimens for some SCN8A patients; however, to date, there are no clinical trials that have evaluated the therapeutic potential of CBD in patients with SCN8A mutations. In the current manuscript, we demonstrated a dose-dependent increase in seizure resistance following CBD treatment in mice expressing the human SCN8A mutation R1620L (RL/+). We also found that CBD treatment improved social behavior and reduced hyperactivity in the RL/+ mutants. Our findings suggest that CBD may be beneficial in patients with SCN8A-associated disease.

Effects of Epidiolex® (Cannabidiol) on seizure-related emergency department visits and hospital admissions: A retrospective cohort study

AIM

The aim of this study was to evaluate the potential impact of cannabidiol (CBD) on healthcare resource utilization and determine the effect of CBD on seizure-related emergency departments (ED) and hospital admissions in patients with epilepsy.

METHODS

This single-center, retrospective longitudinal cohort study included patients ≥1 year on CBD, excluding participants in CBD clinical trials or on <6 months of CBD therapy. Demographics, antiseizure medications (ASM), ED and hospital admissions were collected from the electronic medical record. Co-primary outcomes included change in seizure-related ED and hospital admissions. Secondary outcomes included change in ASMs and total ED or hospital admissions. Co-primary outcomes were assessed using generalized linear modeling. Descriptive statistics were used to analyze all other variables.

RESULTS

In the one-hundred total patients, there was no difference in either seizure-related ED visits (0.012 vs 0.011, p = 0.85) or hospital admissions per month (0.019 vs 0.021, p = 0.7). However, given the low percentage of the total cohort (n = 100) with either a seizure-related ED visits and hospital admissions (9% and 18%, respectively), a subgroup analysis was conducted. Those with seizure-related hospital admissions prior to CBD (n = 18) had significantly less seizure-related hospital admissions after initiation of CBD (23 admissions [0.104 per month] vs 15 admissions [0.055 per month], p = 0.007).

CONCLUSION

Despite the lack of statistically significant difference in primary outcomes for the total cohort, CBD may have a potential for a clinically beneficial impact in real-world settings on those patients with prior seizure-related admissions, who are the highest utilizers of healthcare resources.

Long-term use of cannabidiol-enriched medical cannabis in a prospective cohort of children with drug-resistant developmental and epileptic encephalopathy

OBJECTIVE

We report our findings regarding effectiveness, safety, and tolerability of cannabidiol (CBD)-enriched medical cannabis as add-on therapy in children with drug-resistant epileptic encephalopathies (DEEs) after a median follow-up of 20 months.

METHODS

A prospective cohort study was conducted to assess effectiveness, safety, and tolerability of CBD-enriched medical cannabis oil added to standard antiseizure medications in children with drug-resistant DEE seen at a single center.

RESULTS

Between October 2018 and March 2020, 59 patients were enrolled. Mean age at enrollment was 10.5 years (range, 2-17 years). Median treatment duration was 20 months (range, 12-32). Median age at first seizure was 8 months (range, 1 day - 10 years). At the end of follow-up, 78% of the children had a ≥ 50% decrease in seizure frequency and 47.5% had a > 75% decrease. Seven patients (11.9%) were seizure free. The number of seizures was reduced from a median of 305/month to 90/month, amounting to a mean reduction of 57% and a median reduction of 71% (p < 0.0001). Adverse effects were mostly mild or moderate. CBD was discontinued in 17 patients (28.8%) due to lack of response to treatment, increased seizure frequency, intolerance to the drug, or poor compliance.

CONCLUSION

In children with drug-resistant DEEs, long-term treatment of CBD-enriched medical cannabis as an adjuvant therapy to antiseizure therapy was found to be safe, well tolerated, and effective. Sustained reductions in seizure frequency and improvement of aspects of daily living were observed compared to our preliminary findings.

Long-term cannabidiol treatment for seizures in patients with tuberous sclerosis complex: An open-label extension trial

Objective

To evaluate the long‐term safety and efficacy of add‐on cannabidiol (CBD) in patients with seizures associated with tuberous sclerosis complex (TSC) in the open‐label extension (OLE) of the randomized, placebo‐controlled phase 3 trial GWPCARE6 (NCT02544763). Results of an interim (February 2019 data cut) analysis are reported.

Methods

Patients who completed the randomized trial enrolled to receive CBD (Epidiolex^® in the United States; Epidyolex^® in the EU; 100 mg/mL oral solution). The initial target dose was 25 mg/kg/day, which, based on response and tolerability, could be decreased or increased up to 50 mg/kg/day. The primary end point was safety. Key secondary end points included percentage reduction in TSC‐associated (countable focal and generalized) seizures, responder rates, and Subject/Caregiver Global Impression of Change (S/CGIC).

Results

Of 201 patients who completed the randomized phase, 199 (99%) entered the OLE. Mean age was 13 years (range, 1–57). At the time of analysis, 5% of patients had completed treatment, 20% had withdrawn, and 75% were ongoing. One‐year retention rate was 79%. Median treatment time was 267 days (range, 18–910) at a 27 mg/kg/day mean modal dose. Most patients (92%) had an adverse event (AE). Most common AEs were diarrhea (42%), seizure (22%), and decreased appetite (20%). AEs led to permanent discontinuation in 6% of patients. There was one death that was deemed treatment unrelated by the investigator. Elevated liver transaminases occurred in 17 patients (9%) patients; 12 were taking valproate. Median percentage reductions in seizure frequency (12‐week windows across 48 weeks) were 54%–68%. Seizure responder rates (≥50%, ≥75%, 100% reduction) were 53%–61%, 29%–45%, and 6%–11% across 12‐week windows for 48 weeks. Improvement on the S/CGIC scale was reported by 87% of patients/caregivers at 26 weeks.

Significance

In patients with TSC, long‐term add‐on CBD treatment was well tolerated and sustainably reduced seizures through 48 weeks, with most patients/caregivers reporting global improvement.

Medical cannabis for severe treatment resistant epilepsy in children: a case-series of 10 patients

Objectives

To report the findings of a case-series of 10 children suffering with intractable epilepsies in the UK to determine the feasibility for using whole-plant cannabis medicines to treat seizures in children.

Setting

This study was conducted retrospectively through collecting clinical data from caretakers and clinicians on study outcome variables. Participants were recruited through the MedCann Support and End our Pain charity groups which are patient representative groups that support children who are using medical cannabis to treat their epilepsies. Medicines were prescribed to patients by clinicians in both National Health Service and private medical practices. Follow-up calls were conducted throughout the period January 2021 to May 2021 to keep data recorded up to date.

Participants

Ten children, 18 years old or under, with intractable epilepsies were recruited from two charities. There were no limitations on diagnosis, sex or ethnic origin.

Interventions

Participants were treated with a range of whole-plant medical cannabis oils. Individual dosing regimens were determined by clinicians.

Primary outcome measure

The primary outcome measure was seizure frequency.

Results

Seizure frequency across all 10 participants reduced by 86% with no significant adverse events. Participants reduced use of antiepileptic drugs from an average of seven to one following treatment with medical cannabis. We also noted significant financial costs of £874 per month to obtain these medicines through private prescriptions.

Conclusions

This study establishes the feasibility of whole-plant medical cannabis as an effective and well-tolerated medicine for reducing seizure frequency in children suffering with intractable epilepsies. These findings justify the potential value of further research into the reported therapeutic benefit of whole-plant medicinal cannabis products.

Preclinical investigation of β-caryophyllene as a therapeutic agent in an experimental murine model of Dravet syndrome

Dravet Syndrome (DS) is caused by mutations in the Scn1a gene encoding the α1 subunit of the sodium channel Nav1.1, which results in febrile seizures that progress to severe tonic-clonic seizures and associated comorbidities. Treatment with cannabidiol has been approved for the management of seizures in DS patients, but it appears to be also active against associated comorbidities. In this new study, we have investigated β-caryophyllene (BCP), a cannabinoid with terpene structure that appears to also have a broad-spectrum profile, as a useful therapy against both seizuring activity and progression of associated comorbidities. This has been studied in heterozygous conditional knock-in mice carrying a missense mutation (A1783V) in Scn1a gene expressed exclusively in neurons of the Central Nervous System (Syn-Cre/Scn1a^WT/A1783V), using two experimental approaches. In the first approach, an acute treatment with BCP was effective against seizuring activity induced by pentylenetetrazole (PTZ) in wildtype (Scn1a^WT/WT) and also in Syn-Cre/Scn1a^WT/A1783V mice, with these last animals having a greater susceptibility to PTZ. Such benefits were paralleled by a BCP-induced reduction in PTZ-induced reactive astrogliosis (labelled with GFAP) and microgliosis (labelled with Iba-1) in the prefrontal cortex and the hippocampal dentate gyrus, which were visible in both wildtype (Scn1a^WT/WT) and Syn-Cre/Scn1a^WT/A1783V mice. In the second approach, both genotypes were treated repeatedly with BCP to investigate its effects on several DS comorbidities. Thus, BCP corrected important behavioural abnormalities of Syn-Cre/Scn1a^WT/A1783V mice (e.g. delayed appearance of hindlimb grasp reflex, induction of clasping response, motor hyperactivity, altered social interaction and memory impairment), attenuated weight loss, and slightly delayed premature mortality. Again, these benefits were paralleled by a BCP-induced reduction in reactive astrogliosis and microgliosis in the prefrontal cortex and the hippocampal dentate gyrus typical of Syn-Cre/Scn1a^WT/A1783V mice. In conclusion, BCP was active in Syn-Cre/Scn1a^WT/A1783V mice against seizuring activity (acute treatment) and against several comorbidities (repeated treatment), in both cases in association with its capability to reduce glial reactivity in areas related to these behavioural abnormalities. This situates BCP in a promising position for further preclinical evaluation towards a close translation to DS patients.

Cannabinoids in the Treatment of Epilepsy: A Review

Cannabinoids have been studied for their role in the treatment of epilepsy for many years. The U.S. Food and Drug Administration (FDA) approved them for the treatment of some refractory syndromes in 2018. Cannabidiol and tetrahydrocannabinol are the most commonly studied cannabinoids and have been studied in great depth vis-à-vis their pharmacokinetics and pharmacodynamics. Studies have shown the efficacy of cannabinoids in the treatment of refractory epilepsy. A substantial amount of research has been performed exploring the interactions between cannabinoids and other conventional antiseizure medications. The exact mechanisms by which cannabinoids exert their effects on seizure control remain unclear and research into these mechanisms continues in great earnest. Cognitive changes from cannabinoids are constantly being studied and add to potential benefits from the use of these compounds. Cultural and social misconceptions and roadblocks about the use of cannabinoids persist and represent an ongoing obstacle to increasing research and therapeutic use of these compounds. This review focuses on all these aspects and of the use of these cannabinoids in the treatment of epilepsy and seeks to offer a fairly comprehensive description of the facets of cannabinoid therapy for refractory epilepsy.

The current understanding of the benefits, safety, and regulation of cannabidiol in consumer products

The popularity of cannabidiol (CBD) in consumer products is soaring as consumers are using CBD for general health and well-being as well as to seek relief from ailments especially pain, inflammation, anxiety, depression, and sleep disorders. However, there are limited data currently in the public domain that provide support for these benefits. By contrast, a significant amount of safety evaluation data for CBD have been obtained recently from pre-clinical and clinical studies of the CBD therapeutic Epidiolex®. Yet some key data gaps concerning the safe use of CBD still remain. Furthermore, current regulations on CBD use in consumer products remain uncertain and often conflict between the state and federal level. In light of the rapidly expanding popularity of CBD-related products in the marketplace, here we review the current understanding of the benefits, safety, and regulations surrounding CBD in consumer products. This review does not advocate for or against the use of CBD in consumer products. Rather this review seeks to assess the state-of-the-science on the health effects and safety of CBD, to identify critical knowledge gaps for future studies, and to raise the awareness of the current regulations that govern CBD use in consumer products.

The perceived effects of cannabis products in the management of seizures in CDKL5 Deficiency Disorder

INTRODUCTION

CDKL5 Deficiency Disorder (CDD) is a severe treatment-resistant form of early-onset epilepsy. Current treatment options are often ineffective and associated with adverse effects, forcing families to seek alternative therapies for their children including products derived from cannabis. Reportsof miraculous cures and a public preferencefor 'natural' therapies have resulted in considerable public interest, and so this study aimed to characterize the use of cannabis in these individuals, as well as compare caregiver perceptions of efficacy and safety to objective evidence of seizure control and number of antiepileptic drugs used.

METHODS

Families from the International CDKL5 Disorder Database were invited to complete questionnaires which included data relating to their child's current and past treatments, including use of any cannabis-derived preparations. Perceived effects on seizure control, as well as additional benefits and adverse effects were reported. Seizure frequency and number of antiepileptic drugs were compared between those actively using cannabis products and those who were not. Longitudinal analysis was performed on a subset of the study population to compare these same variables at pre-treatment and post-treatment time points.

RESULTS

Three hundred and twelve caregivers answered questions regarding their child's use of antiepileptic medications. Of these, 82 (26%) described use of cannabis preparations either at present, or in the past, with the most common being cannabidiol. Of 70 caregivers that described their perceived effect on seizure control, more than two thirds reported an improvement in seizure control, either temporary (16%) or lasting (54%). Additional benefits included improvements in attention, cognition, and sleep. The majority of responses (78%) described adverse effects as 'none', though some reported an increase in sedation and gastrointestinal upset. There was no reduction in the median seizure frequency nor the number of different antiepileptic drugs, for those who were actively using cannabis products compared to those who were not. Similarly, individuals who were not using cannabis products at an initial time point had no differences in seizure frequency nor number of antiepileptic drugs at a second timepoint when they had started using this treatment.

CONCLUSIONS

Although this is an observational study, limited by potential participation bias and the unreliable nature of unblinded self-assessment, it suggests that caregivers perceive cannabis products, especially cannabidiol, to have a tolerable adverse effect profile and adequate efficacy. Despite this, cannabis was not associated with a reduction in seizure frequency nor number of antiepileptic drugs when compared to non-users or when compared to pre-treatment. Randomized controlled trials are urgently needed to more reliably assess this treatment's safety and efficacy.

Headache in people with epilepsy

Epidemiological estimates indicate that individuals with epilepsy are more likely to experience headaches, including migraine, than individuals without epilepsy. Headaches can be temporally unrelated to seizures, or can occur before, during or after an episode; seizures and migraine attacks are mostly not temporally linked. The pathophysiological links between headaches (including migraine) and epilepsy are complex and have not yet been fully elucidated. Correct diagnoses and appropriate treatment of headaches in individuals with epilepsy is essential, as headaches can contribute substantially to disease burden. Here, we review the insights that have been made into the associations between headache and epilepsy over the past 5 years, including information on the pathophysiological mechanisms and genetic variants that link the two disorders. We also discuss the current best practice for the management of headaches co-occurring with epilepsy and highlight future challenges for this area of research.

Long-term safety and efficacy of add-on cannabidiol in patients with Lennox-Gastaut syndrome: Results of a long-term open-label extension trial

OBJECTIVE

Lennox-Gastaut syndrome (LGS) is an epileptic encephalopathy that is often treatment resistant. Efficacy and safety of add-on cannabidiol (CBD) to treat seizures associated with LGS was demonstrated in two randomized controlled trials (RCTs). Patients who completed the RCTs were invited to enroll in this long-term open-label extension (OLE) trial, GWPCARE5 (NCT02224573). We present the final analysis of safety and efficacy outcomes from GWPCARE5.

METHODS

Patients received plant-derived highly purified CBD (Epidiolex in the United States; Epidyolex in the European Union; 100 mg/ml oral solution), titrated to a target maintenance dose of 20 mg/kg/day over 2 weeks. Based on response and tolerability, CBD could then be reduced or increased up to 30 mg/kg/day.

RESULTS

Of 368 patients with LGS who completed the RCTs, 366 (99.5%) enrolled in this OLE. Median and mean treatment duration were 1090 and 826 days (range = 3-1421), respectively, with a mean modal dose of 24 mg/kg/day. Adverse events (AEs) occurred in 96% of patients, serious AEs in 42%, and AE-related discontinuations in 12%. Common AEs were convulsion (39%), diarrhea (38%), pyrexia (34%), and somnolence (29%). Fifty-five (15%) patients experienced liver transaminase elevations more than three times the upper limit of normal; 40 (73%) were taking concomitant valproic acid. Median percent reductions from baseline ranged 48%-71% for drop seizures and 48%-68% for total seizures through 156 weeks. Across all 12-week visit windows, 87% or more of patients/caregivers reported improvement in the patient's overall condition on the Subject/Caregiver Global Impression of Change scale.

SIGNIFICANCE

Long-term add-on CBD treatment had a similar safety profile as in the original RCTs. Sustained reductions in drop and total seizure frequency were observed for up to 156 weeks, demonstrating long-term benefits of CBD treatment for patients with LGS.

Cannabidiol use and effectiveness: real-world evidence from a Canadian medical cannabis clinic

BACKGROUND

Cannabidiol (CBD) is a primary component in the cannabis plant; however, in recent years, interest in CBD treatments has outpaced scientific research and regulatory advancement resulting in a confusing landscape of misinformation and unsubstantiated health claims. Within the limited results from randomized controlled trials, and lack of trust in product quality and known clinical guidelines and dosages, real-world evidence (RWE) from countries with robust regulatory frameworks may fill a critical need for patients and healthcare professionals. Despite growing evidence and interest, no real-world data (RWD) studies have yet investigated patients' reports of CBD impact on symptom control in the common expression of pain, anxiety, depression, and poor wellbeing. The objective of this study is to assess the impact of CBD-rich treatment on symptom burden, as measured with a specific symptom assessment scale (ESAS-r).

METHODS

This retrospective observational study examined pain, anxiety, depression symptoms, and wellbeing in 279 participants over 18 years old, prescribed with CBD-rich treatment at a network of clinics dedicated to medical cannabis in Quebec, Canada. Data were collected at baseline, 3 (FUP1), and 6 (FUP2) month after treatment initiation. Groups were formed based on symptom severity (mild vs moderate/severe) and based on changes to treatment plan at FUP1 (CBD vs THC:CBD). Two-way mixed ANOVAs were used to assess ESAS-r scores differences between groups and between visits.

RESULTS

All average ESAS-r scores decreased between baseline and FUP1 (all ps < 0.003). The addition of delta-9-tetrahydrocannabinol (THC) during the first follow-up had no effect on symptom changes. Patients with moderate/severe symptoms experienced important improvement at FUP1 (all ps < 0.001), whereas scores on pain, anxiety, and wellbeing of those with mild symptoms actually increased. Differences in ESAS-r scores between FUP1 and FUP2 were not statistically different.

CONCLUSION

This retrospective observational study suggests CBD-rich treatment has a beneficial impact on pain, anxiety, and depression symptoms as well as overall wellbeing only for patients with moderate to severe symptoms; however, no observed effect on mild symptoms. The results of this study contribute to address the myths and misinformation about CBD treatment and demand further investigation.

Cannabidiol Inhibition of Murine Primary Nociceptors: Tight Binding to Slow Inactivated States of Nav1.8 Channels

The nonpsychoactive phytocannabinoid cannabidiol (CBD) has been shown to have analgesic effects in animal studies but little is known about its mechanism of action. We examined the effects of CBD on intrinsic excitability of primary pain-sensing neurons. Studying acutely dissociated capsaicin-sensitive mouse DRG neurons at 37°C, we found that CBD effectively inhibited repetitive action potential firing, from 15-20 action potentials evoked by 1 s current injections in control to 1-3 action potentials with 2 μm CBD. Reduction of repetitive firing was accompanied by a reduction of action potential height, widening of action potentials, reduction of the afterhyperpolarization, and increased propensity to enter depolarization block. Voltage-clamp experiments showed that CBD inhibited both TTX-sensitive and TTX-resistant (TTX-R) sodium currents in a use-dependent manner. CBD showed strong state-dependent inhibition of TTX-R channels, with fast binding to inactivated channels during depolarizations and slow unbinding on repolarization. CBD alteration of channel availability at various voltages suggested that CBD binds especially tightly [K _d (dissociation constant), ∼150 nm] to the slow inactivated state of TTX-R channels, which can be substantially occupied at voltages as negative as -40 mV. Remarkably, CBD was more potent in inhibiting TTX-R channels and inhibiting action potential firing than the local anesthetic bupivacaine. We conclude that CBD might produce some of its analgesic effects by direct effects on neuronal excitability, with tight binding to the slow inactivated state of Na_v1.8 channels contributing to effective inhibition of repetitive firing by modest depolarizations.SIGNIFICANCE STATEMENT Cannabidiol (CBD) has been shown to inhibit pain in various rodent models, but the mechanism of this effect is unknown. We describe the ability of CBD to inhibit repetitive action potential firing in primary nociceptive neurons from mouse dorsal root ganglia and analyze the effects on voltage-dependent sodium channels. We find that CBD interacts with TTX-resistant sodium channels in a state-dependent manner suggesting particularly tight binding to slow inactivated states of Na_v1.8 channels, which dominate the overall inactivation of Na_v1.8 channels for small maintained depolarizations from the resting potential. The results suggest that CBD can exert analgesic effects in part by directly inhibiting repetitive firing of primary nociceptors and suggest a strategy of identifying compounds that bind selectively to slow inactivated states of Na_v1.8 channels for developing effective analgesics.

A Mapping Literature Review of Medical Cannabis Clinical Outcomes and Quality of Evidence in Approved Conditions in the USA from 2016 to 2019

In 2017, a National Academies of Sciences, Engineering, and Medicine (NASEM) report comprehensively evaluated the body of evidence regarding cannabis health effects through the year 2016. The objectives of this study are to identify and map the most recently (2016-2019) published literature across approved conditions for medical cannabis and to evaluate the quality of identified recent systematic reviews, published following the NASEM report. Following the literature search from 5 databases and consultation with experts, 11 conditions were identified for evidence compilation and evaluation: amyotrophic lateral sclerosis, autism, cancer, chronic noncancer pain, Crohn's disease, epilepsy, glaucoma, human immunodeficiency virus/AIDS, multiple sclerosis (MS), Parkinson's disease, and posttraumatic stress disorder. A total of 198 studies were included after screening for condition-specific relevance and after imposing the following exclusion criteria: preclinical focus, non-English language, abstracts only, editorials/commentary, case studies/series, and non-U.S. study setting. Data extracted from studies included: study design type, outcome definition, intervention definition, sample size, study setting, and reported effect size. Few completed randomized controlled trials (RCTs) were identified. Studies classified as systematic reviews were graded using the Assessing the Methodological Quality of Systematic Reviews-2 tool to evaluate the quality of evidence. Few high-quality systematic reviews were available for most conditions, with the exceptions of MS (9 of 9 graded moderate/high quality; evidence for 2/9 indicating cannabis improved outcomes; evidence for 7/9 indicating cannabis inconclusive), epilepsy (3 of 4 graded moderate/high quality; 3 indicating cannabis improved outcomes; 1 indicating cannabis inconclusive), and chronic noncancer pain (12 of 13 graded moderate/high quality; evidence for 7/13 indicating cannabis improved outcomes; evidence from 6/7 indicating cannabis inconclusive). Among RCTs, we identified few studies of substantial rigor and quality to contribute to the evidence base. However, there are some conditions for which significant evidence suggests that select dosage forms and routes of administration likely have favorable risk-benefit ratios (i.e., epilepsy and chronic noncancer pain). The body of evidence for medical cannabis requires more rigorous evaluation before consideration as a treatment option for many conditions, and evidence necessary to inform policy and treatment guidelines is currently insufficient for many conditions.

Time to onset of cannabidiol (CBD) treatment effect in Lennox-Gastaut syndrome: Analysis from two randomized controlled trials

OBJECTIVE

To estimate time to onset of cannabidiol (CBD) treatment effect (seizure reduction and adverse events [AEs]), we conducted post hoc analyses of data from two randomized, placebo-controlled, Phase 3 trials, GWPCARE3 (NCT02224560) and GWPCARE4 (NCT02224690), of patients with Lennox-Gastaut syndrome.

METHODS

Patients received plant-derived pharmaceutical formulation of highly purified CBD (Epidiolex, 100 mg/ml oral solution) at 10 mg/kg/day (CBD10; GWPCARE3) or 20 mg/kg/day (CBD20; both trials) or placebo for 14 weeks. Treatment started at 2.5 mg/kg/day for all groups and reached 10 mg/kg/day on Day 7 and 20 mg/kg/day (CBD20 and matching placebo only) on Day 11. Percentage change from baseline in drop seizure frequency was calculated by cumulative day (i.e., including all previous days). Time to onset and resolution of AEs were evaluated.

RESULTS

Overall, 235 patients received CBD (CBD10 [GWPCARE3 only], n = 67; CBD20 [pooled GWPCARE3&4], n = 168) and 161 received placebo. Mean (range) age was 15.3 years (2.6-48.0). Patients had previously discontinued a median (range) of six (0-28) antiepileptic drugs (AEDs) and were currently taking a median of three (0-5) AEDs. Differences in drop seizure reduction between placebo and CBD emerged during the titration period and became nominally significant by Day 6 (p = .008) for pooled CBD treatment groups. Separation between placebo and CBD in ≥50% responder rate emerged by Day 6. Onset of the first reported AE occurred during the titration period in 45% of patients (CBD10, 46%; CBD20, 52%; placebo, 38%). In patients with AEs, resolution occurred within 4 weeks of onset in 53% of placebo and 39% of CBD patients and by end of study in 63% of placebo and 61% of CBD patients.

SIGNIFICANCE

Treatment effect (efficacy and AEs) of CBD may occur within 1 week of starting treatment. Although AEs lasted longer for CBD than placebo, most resolved within the 14-week period.

Cannabidiol in Pharmacoresistant Epilepsy: Clinical Pharmacokinetic Data From an Expanded Access Program

Background and Aim: Data on the clinical pharmacokinetics of cannabidiol (CBD) are scanty. We explored the effect of demographic and clinical variables on plasma concentrations of purified CBD in patients with Dravet (DS) and Lennox–Gastaut syndrome (LGS).

Methods: The study design was an open, prospective, multicenter expanded access program (EAP). Venous blood samples were drawn from patients between 8 and 9 am, before the CBD morning dose, 12 h apart from the last evening dose, and then 2.5 h after their usual morning dose.

Results: We collected 127 plasma samples (67-morning pre-dosing and 60 post-dosing) from 43 patients (24 females, 19 males), 27 with LGS and 16 with DS. Mean ± standard deviation age was 26 ± 15 years. Duration of CBD treatment averaged 4.2 ± 2.9 months at 13.2 ± 4.6 mg/kg/day. CBD median trough plasma concentration was 91 ng/ml; it doubled to 190 ng/ml 2.5 h post-dosing (p < 0.001). Cannabidiol trough plasma concentrations were linearly related to daily doses (r = 0.564, p < 0.001). Median trough CBD plasma concentration-to-weight-adjusted dose ratio (C/D) was 32% higher (p < 0.02) in plasma samples from subjects aged 18 and over than in those under 18. Sex and concomitant antiseizure medications (ASMs) were not associated with significant variations in CBD C/D, but caution is required due to the potential influence of confounders.

Conclusion: These are the first data on CBD pharmacokinetics in children and adults with LGS or DS in a real-world setting. The most relevant finding was the higher CBD C/D in adults. In practice, reduced weight-normalized doses might be required with aging to achieve the same CBD plasma levels.

The role of new medical treatments for the management of developmental and epileptic encephalopathies: Novel concepts and results

Developmental and epileptic encephalopathies (DEEs) are among the most challenging of all epilepsies to manage, given the exceedingly frequent and often severe seizure types, pharmacoresistance to conventional antiseizure medications, and numerous comorbidities. During the past decade, efforts have focused on development of new treatment options for DEEs, with several recently approved in the United States or Europe, including cannabidiol as an orphan drug in Dravet and Lennox-Gastaut syndromes and everolimus as a possible antiepileptogenic and precision drug for tuberous sclerosis complex, with its impact on the mammalian target of rapamycin pathway. Furthermore, fenfluramine, an old drug, was repurposed as a novel therapy in the treatment of Dravet syndrome. The evolution of new insights into pathophysiological processes of various DEEs provides possibilities to investigate novel and repurposed drugs and to place them into the context of their role in future management of these patients. The purpose of this review is to provide an overview of these new medical treatment options for the DEEs and to discuss the clinical implications of these results for improved treatment.

Cannabidiol in the Treatment of Epilepsy

Anecdotal reports addressing the successful seizure treatment of severe epilepsies with cannabidiol (CBD) have increased both public interest and academic research. Placebo-controlled, randomized, controlled trials proved the efficacy of pharmaceutical-grade CBD in epilepsy treatment, thus leading to pharmaceutical-grade CBD approval by the US Food and Drug Administration and the European Medicines Agency for the treatment of seizures in Dravet syndrome and Lennox–Gastaut syndrome as well as for tuberous complex syndrome by the Food and Drug Administration only. However, the CBD market is confusing because an array of products of different origins, purity, and concentration is available. Additionally, the results from the pivotal studies with plant-derived, pharmaceutical-grade CBD cannot simply be transferred to other epilepsy types or CBD of any origin. Because of the high demands and expectations that patients with epilepsy and their caregivers have regarding CBD, information outlining the proven facts and potential risks is essential. The aim of this article is to thoroughly review available research data and practical recommendations to provide the treating physician with the necessary information for counseling patients with epilepsy.

Expanding the Treatment Landscape for Lennox-Gastaut Syndrome: Current and Future Strategies

Lennox-Gastaut syndrome (LGS), a childhood-onset severe developmental and epileptic encephalopathy (DEE), is an entity that encompasses a heterogenous group of aetiologies, with no single genetic cause. It is characterised by multiple seizure types, an abnormal EEG with generalised slow spike and wave discharges and cognitive impairment, associated with high morbidity and profound effects on the quality of life of patients and their families. Drug-refractory seizures are a hallmark and treatment is further complicated by its multiple morbidities, which evolve over the patient's lifetime. This review provides a comprehensive overview of the current and future options for the treatment of seizures associated with LGS. Six treatments are specifically indicated as adjunct therapies for the treatment of seizures associated with LGS in the US: lamotrigine, clobazam, rufinamide, topiramate, felbamate and most recently cannabidiol. These therapies have demonstrated reductions in drop seizures in 15%-68% of patients across trials, with responder rates (≥ 50% reduction in drop seizures) of 37%-78%. Valproate is still the preferred first-line treatment, generally in combination with lamotrigine or clobazam. Other treatments frequently used off-label include the broad spectrum anti-epileptic drugs (AED) levetiracetam, zonisamide and perampanel, while recent evidence from observational studies has indicated that a newer AED, the levetiracetam analogue brivaracetam, may be effective and well tolerated in LGS patients. Other treatments in clinical development include fenfluramine in late phase III, perampanel, soticlestat-OV953/TAK-953, carisbamate and ganaxolone. Non-pharmacologic interventions include the ketogenic diet, vagus nerve stimulation and surgical interventions; these are also expanding, with the potential for less invasive techniques for corpus callosotomy that have promise for reducing complications. However, despite these advancements, patients continue to experience a significant burden. Because LGS is not a single entity, tailoring of treatment is needed as opposed to a 'one size fits all' approach. Further research is needed into the underlying aetiologies and pathophysiology of LGS, together with advancements in treatments that encompass the spectrum of seizures associated with this complex syndrome.

Safety Considerations in Cannabinoid-Based Medicine

Cannabinoids are a diverse class of chemical compounds that are increasingly recognized as potential therapeutic options for a range of conditions. While many studies and reviews of cannabinoids focus on efficacy, safety is much less well reported. Overall assessment of the safety of cannabinoid-based medicines is confounded by confusion with recreational cannabis use as well as different study designs, indications, dosing, and administration methods. However, clinical studies in registered products are increasingly available, and this article aims to discuss and clarify what is known regarding the safety profiles of cannabinoid-based medicines, focusing on the medical and clinical safety evidence and identifying areas for future research. The two most well-studied cannabinoids are Δ9-tetrahydrocannabinol (THC), or its synthetic variants (dronabinol, nabilone), and cannabidiol (CBD). Across diverse indications, dizziness and fatigue are generally the most common adverse events experienced by patients receiving THC or combined THC and CBD. Patients receiving THC may experience adverse cognitive effects and impairment in psychomotor skills, with implications for driving and some occupations, while CBD may help to lower the psychotropic effects of THC when used in combination. Studies on dependency and addiction in a medical context are limited, but have shown inconsistent findings regarding misuse potential. Generally, the recommended route of administration is oral ingestion, as smoking medicinal cannabinoid products potentially releases mutagenic and carcinogenic by-products. There are several potential drug-drug interactions and contraindications for cannabinoid-based medicines, which physicians should account for when making prescribing decisions. The available evidence shows that, as with any other class of pharmaceuticals, cannabinoid-based medicines are associated with safety risks which should be assessed in the context of potential therapeutic benefits. Each patient should be assessed on an individual basis and physicians must rely on informed, evidence-based decision-making when determining whether a cannabinoid-based medicine could be an appropriate treatment option.