Cannabidiol as adjunctive treatment of seizures associated with Lennox-Gastaut syndrome and Dravet syndrome

Cannabidiol and neurodegeneration: From molecular mechanisms to clinical benefits

Neurodegenerative disorders (NDs) such as Alzheimer's disease, Parkinson's disease, Huntington's disease, multiple sclerosis, and amyotrophic lateral sclerosis are severe and life-threatening conditions in which significant damage of functional neurons occurs to produce psycho-motor malfunctions. NDs are an important cause of death in the elderly population worldwide. These disorders are commonly associated with the progression of age, oxidative stress, and environmental pollutants, which are the major etiological factors. Abnormal aggregation of specific proteins such as α-synuclein, amyloid-β, huntingtin, and tau, and accumulation of the associated oligomers in neurons are the hallmark pathological features of NDs. Existing therapeutic options for NDs are only symptomatic relief and do not address root-causing factors, such as protein aggregation, oxidative stress, and neuroinflammation. Cannabidiol (CBD) is a non-psychotic natural cannabinoid obtained from Cannabis sativa that possesses multiple pharmacological actions, including antioxidant, anti-inflammatory, and neuroprotective effects in various NDs and other neurological disorders both in vitro and in vivo. CBD has gained attention as a promising drug candidate for the management of neurodegenerative disorders, such as Alzheimer's disease and Parkinson's disease, by inhibiting protein aggregation, free radicals, and neuroinflammation. In parallel, CBD has shown positive results in other neurological disorders, such as epilepsy, depression, schizophrenia, and anxiety, as well as adjuvant treatment with existing standard therapeutic agents. Hence, the present review focuses on exploring the possible molecular mechanisms in controlling various neurological disorders as well as the clinical applications of CBD in NDs including epilepsy, depression and anxiety. In this way, the current review will serve as a standalone reference for the researchers working in this area.

Real-world experience with cannabidiol as add-on treatment in drug-resistant epilepsy

PURPOSE

To evaluate the efficacy and safety of cannabidiol (CBD) for the treatment of epilepsy in a real-world setting.

METHODS

In this retrospective observational study, we included PwE with epilepsy who received a prescription for CBD between 01.03.2019 and 30.11.2022 and had a follow-up period ≥ 3 months. Participants were evaluated at baseline and after 3, 6, and 12 months. "Responders" were defined as individuals experiencing a reduction in seizure frequency > 30% but < 80% compared to baseline, while "super responders" were those with a reduction ≥ 80%. Adverse events were recorded to assess safety.

RESULTS

Forty-two PwE were included (mean age 36.1 ± 10.9 years; 14 females). In 24 patients CBD was prescribed on-label (Lennox-Gastaut syndrome, n = 18; Dravet syndrome, n = 5; tuberous sclerosis, n = 1), while 18 patients were treated off-label (ring chromosome 20 syndrome, n = 1; ring chromosome 17 syndrome, n = 1; Lafora disease, n = 3; Unverricht-Lundborg disease, n = 1; polymicrogyria, n = 2; febrile infection-related epilepsy syndrome, n = 1; non-lesional focal epilepsy, n = 2; developmental and/or epileptic encephalopathy of unknown etiology n = 6). The mean number of concomitant antiseizure medications was 3.4 (≥2 for all patients). At 3 months, 10 subjects (23%) were "responders" and 12 (29%) were "super-responders". Efficacy was sustained at 6 and 12 months of follow-up. Twenty-two patients (52.3%) developed AEs, with drowsiness (36.5%) and diarrhea (9.8%) being the most common. The retention rate was 85.7%, 78.6%, and 71.4% at 3, 6, and 12 months, respectively.

CONCLUSIONS

In this monocentric real-world study, CBD was a safe and effective therapeutic option for highly drug-resistant patients, leading to a dramatic reduction in seizure frequency in over one-fourth of them, including off-label indications.

Behavioral effects induced by the cannabidiol analogs HU-502 and HU-556

Cannabidiol is a phytocannabinoid that lacks the psychotomimetic properties of Δ9-tetrahydrocannabinol (THC), the main psychoactive Cannabis sativa component. Cannabidiol has several potential therapeutic properties, including anxiolytic, antidepressant, and antipsychotic; however, cannabidiol has low oral bioavailability, which can limit its clinical use. Here, we investigated if two cannabidiol analogs, HU-502 and HU-556, would be more potent than cannabidiol in behavioral tests predictive of anxiolytic, antidepressant, and antipsychotic effects. Different doses (0.01-3 mg/kg; intraperitoneally) of HU-556 and HU-502 were tested in male Swiss mice submitted to the elevated plus maze (EPM), forced swimming test (FST), and amphetamine-induced-prepulse inhibition (PPI) disruption and hyperlocomotion. Cannabidiol is effective in these tests at a dose range of 15-60 mg/kg in mice. We also investigated if higher doses of HU-556 (3 and 10 mg/kg) and HU-502 (10 mg/kg) produced the cannabinoid tetrad (hypolocomotion, catalepsy, hypothermia, and analgesia), which is induced by THC-like compounds. HU-556 (0.1 and 1 mg/kg) increased the percentage of open arm entries (but not time) in the EPM, decreased immobility time in the FST, and attenuated amphetamine-induced PPI disruption. HU-502 (1 and 3 mg/kg) decreased amphetamine-induced hyperlocomotion and PPI impairment. HU-556, at high doses, caused catalepsy and hypolocomotion, while HU-502 did not. These findings suggest that similar to cannabidiol, HU-556 could induce anxiolytic, antidepressant, and antipsychotic-like effects and that HU-502 has antipsychotic properties. These effects were found at a dose range devoid of cannabinoid tetrad effects.

Cannabidiol, ∆9-tetrahydrocannabinol, and metabolites in human blood by volumetric absorptive microsampling and LC-MS/MS following controlled administration in epilepsy patients

Cannabidiol (CBD) exhibits anti-inflammatory, anxiolytic, antiseizure, and neuroprotective proprieties without addictive or psychotropic side effects, as opposed to Δ⁹-tetrahydrocannabinol (THC). While recreational cannabis contains higher THC and lower CBD concentrations, medical cannabis contains THC and CBD in different ratios, along with minor phytocannabinoids, terpenes, flavonoids and other chemicals. A volumetric absorptive microsampling (VAMS) method combined with ultra-high-performance liquid chromatography coupled with mass spectrometry in tandem for quantification of CBD, THC and their respective metabolites: cannabidiol-7-oic acid (7-COOH-CBD); 7-hydroxy-cannabidiol (7-OH-CBD); 6-alpha-hydroxy-cannabidiol (6-α-OH-CBD); and 6-beta-hydroxycannabidiol (6-β-OH-CBD); 11- Hydroxy-Δ⁹-tetrahydrocannabinol (11-OH-THC) and 11-Nor-9-carboxy-Δ⁹-tetrahydrocannabinol (THCCOOH). After overnight enzymatic glucuronide hydrolysis at 37°C, samples underwent acidic along with basic liquid-liquid extraction with hexane: ethyl acetate (9:1, v/v). Chromatographic separation was carried out on a C18 column, with the mass spectrometer operated in multiple reaction monitoring mode and negative electrospray ionization. Seven patients with intractable epilepsy were dosed with various CBD-containing formulations and blood collected just before their daily morning administration. The method was validated following international guidelines in toxicology. Linear ranges were (ng/ml) 0.5–25 THC, 11-OH-THC, THCCOOH, 6-α-OH-CBD and 6-β-OH-CBD; 10–500 CBD and 7-OH-CBD; and 20–5000 7-COOH-CBD. 7-COOH-CBD was present in the highest concentrations, followed by 7-OH-CBD and CBD. This analytical method is useful for investigating CBD, THC and their major metabolites in epilepsy patients treated with CBD preparations employing a minimally invasive microsampling technique requiring only 30 µL blood.

Marijuana use in children: An update focusing on pediatric tetrahydrocannabinol and cannabidiol use

Cannabis is the most used recreational drug in the United States, and its use is increasing among children and adolescents.  With the increase in legalized use, there have been increases in intentional and accidental cannabis exposure in the pediatric population. There is also minimized perceived risk.  We review the current use of cannabis and its derivatives, the drug effects and clinical presentation, common misconceptions, pharmacology, and epidemiology. Finally, we review some long-term consequences of cannabis use.

Improving Therapy of Pharmacoresistant Epilepsies: The Role of Fenfluramine

Epilepsy is among the most common neurological chronic disorders, with a prevalence of 0.5-1%. Despite the introduction of new antiepileptic drugs during recent years, about one third of the epileptic population remain drug-resistant. Hence, especially in the pediatric population limited by different pharmacokinetics and pharmacodynamics and by ethical and regulatory issues it is needed to identify new therapeutic resources. New molecules initially used with other therapeutic indications, such as fenfluramine, are being considered for the treatment of pharmacoresistant epilepsies, including Dravet Syndrome (DS) and Lennox-Gastaut Syndrome (LGS). Drug-refractory seizures are a hallmark of both these conditions and their treatment remains a major challenge. Fenfluramine is an amphetamine derivative that was previously approved as a weight loss drug and later withdrawn when major cardiac adverse events were reported. However, a new role of fenfluramine has emerged in recent years. Indeed, fenfluramine has proved to be a promising antiepileptic drug with a favorable risk-benefit profile for the treatment of DS, LGS and possibly other drug-resistant epileptic syndromes. The mechanism by which fenfluramine provide an antiepileptic action is not fully understood but it seems to go beyond its pro-serotoninergic activity. This review aims to provide a comprehensive analysis of the literature, including ongoing trials, regarding the efficacy and safety of fenfluramine as adjunctive treatment of pharmacoresistant epilepsies.

Channelopathy of Dravet Syndrome and Potential Neuroprotective Effects of Cannabidiol

Dravet syndrome (DS) is a channelopathy, neurodevelopmental, epileptic encephalopathy characterized by seizures, developmental delay, and cognitive impairment that includes susceptibility to thermally induced seizures, spontaneous seizures, ataxia, circadian rhythm and sleep disorders, autistic-like behaviors, and premature death. More than 80% of DS cases are linked to mutations in genes which encode voltage-gated sodium channel subunits, SCN1A and SCN1B, which encode the Nav1.1α subunit and Nav1.1β1 subunit, respectively. There are other gene mutations encoding potassium, calcium, and hyperpolarization-activated cyclic nucleotide-gated (HCN) channels related to DS. One-third of patients have pharmacoresistance epilepsy. DS is unresponsive to standard therapy. Cannabidiol (CBD), a non-psychoactive phytocannabinoid present in Cannabis, has been introduced for treating DS because of its anticonvulsant properties in animal models and humans, especially in pharmacoresistant patients. However, the etiological channelopathiological mechanism of DS and action mechanism of CBD on the channels are unclear. In this review, we summarize evidence of the direct and indirect action mechanism of sodium, potassium, calcium, and HCN channels in DS, especially sodium subunits. Some channels' loss-of-function or gain-of-function in inhibitory or excitatory neurons determine the balance of excitatory and inhibitory are associated with DS. A great variety of mechanisms of CBD anticonvulsant effects are focused on modulating these channels, especially sodium, calcium, and potassium channels, which will shed light on ionic channelopathy of DS and the precise molecular treatment of DS in the future.

Therapeutic Drug Monitoring of Antiseizure Medications Using Volumetric Absorptive Microsampling: Where Are We?

Therapeutic drug monitoring (TDM) of antiseizure medications (ASMs) represents a valuable tool to establish an appropriate patient therapy, to collect important information about drugs’ interactions and to evaluate patient’s metabolic capabilities. In recent years, a new volumetric absorptive microsampling technique using VAMS^® technology and Mitra^® devices, consisting of a sampling technique for the collection of fixed-volume capillary blood, was developed. These new devices provide a new home-sampling technique for whole blood that has been spread out to simplify sample collection from finger-pricks. This review is aimed to compare published articles concerning the application of VAMS^® in epilepsy and to identify the strengths and improvement points for the TDM of antiseizure medications. VAMS^® allowed a minimally invasive blood sampling even in the absence of trained personnel. Good stability data have indicated that storage and delivery can be facilitated only for specific ASMs. Trueness and precision parameters have been evaluated, and the hematocrit (HCT) effect was minimized.

UHPLC-MS/MS Analysis of Cannabidiol and Its Metabolites in Serum of Patients with Resistant Epilepsy Treated with CBD Formulations

Cannabidiol (CBD) is a promising therapeutic agent with analgesic, myorelaxant, and anti-epileptic actions. Recently, a purified form of CBD (Epidiolex^®) has been approved by the European Medicines Agency (EMA) for the treatment of two highly-refractory childhood-onset epilepsies (Dravet and Lennox-Gastaut syndrome). Given the interindividual response and the relationship between the dose administered and CBD blood levels, therapeutic drug monitoring (TDM) is a valuable support in the clinical management of patients. We herein report for the first time a newly developed and validated method using ultra-high-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC–MS/MS) to evaluate CBD and its metabolites (i.e., cannabidiol-7-oic acid (7-COOH-CBD), 7-hydroxycannabidiol (7-OH-CBD), 6-α-hydroxycannabidiol (6-α–OH–CBD) and 6-β-hydroxycannabidiol (6-β–OH–CBD)) in serum samples. The method reached the sensitivity needed to detect minimal amounts of analytes under investigation with limits of quantification ranging from 0.5 to 20 ng/mL. The validation results indicated in this method were accurate (average inter/intra-day error, <15%), precise (inter/intra-day imprecision, <15%), and fast (8 min run time). The method resulted to be linear in the range of 1–10,000 ng/mL for CBD-COOH, 1–500 ng/mL for 7-OH-CBD and CBD and 1–25 ng/mL for 6-α–OH–CBD and 6-β–OH–CBD. Serum levels of CBD (88.20–396.31 and 13.19–170.63 ng/mL) as well as of 7-OH-CBD (27.11–313.63 and 14.01–77.52 ng/mL) and 7-COOH-CBD (380.32–10,112.23 and 300.57–2851.82 ng/mL) were significantly higher (p < 0.05) in patients treated with GW pharma CBD compared to those of patients treated with galenic preparations. 6-α–OH–CBD and 6-β–OH–CBD were detected in the first group and were undetectable in the second group. 7-COOH-CBD was confirmed as the most abundant metabolite in serum (5–10 fold higher than CBD) followed by 7-OH-CBD. A significant correlation (p < 0.05) between the dose administrated and a higher bioavailability was confirmed in patients treated with a GW pharma CBD preparation.

The Pharmacoresistant Epilepsy: An Overview on Existent and New Emerging Therapies

Epilepsy is one of the most common neurological chronic disorders, with an estimated prevalence of 0. 5 - 1%. Currently, treatment options for epilepsy are predominantly based on the administration of symptomatic therapy. Most patients are able to achieve seizure freedom by the first two appropriate drug trials. Thus, patients who cannot reach a satisfactory response after that are defined as pharmacoresistant. However, despite the availability of more than 20 antiseizure medications (ASMs), about one-third of epilepsies remain drug-resistant. The heterogeneity of seizures and epilepsies, the coexistence of comorbidities, and the broad spectrum of efficacy, safety, and tolerability related to the ASMs, make the management of these patients actually challenging. In this review, we analyze the most relevant clinical and pathogenetic issues related to drug-resistant epilepsy, and then we discuss the current evidence about the use of available ASMs and the alternative non-pharmacological approaches.

Highly Purified Cannabidiol for Epilepsy Treatment: A Systematic Review of Epileptic Conditions Beyond Dravet Syndrome and Lennox-Gastaut Syndrome

BACKGROUND

Cannabidiol (CBD), which is one major constituent of the Cannabis sativa plant, has anti-seizure properties and does not produce euphoric or intrusive side effects. A plant-derived, highly purified CBD formulation with a known and constant composition has been approved by the US Food and Drug Administration for the treatment of seizures associated with Dravet syndrome, Lennox-Gastaut syndrome, and tuberous sclerosis complex. In the European Union, the drug has been authorized by the European Medicines Agency for the treatment of seizures associated with Dravet syndrome and Lennox-Gastaut syndrome, in conjunction with clobazam, and is under regulatory review for the treatment of seizures in patients with tuberous sclerosis complex.

OBJECTIVES

This systematic review aimed to summarize the currently available body of knowledge about the use of this US Food and Drug Administration/European Medicines Agency-approved oral formulation of pharmaceutical-grade CBD in patients with epileptic conditions, especially developmental and epileptic encephalopathies other than Dravet syndrome and Lennox-Gastaut syndrome.

METHODS

The relevant studies were identified through MEDLINE and the US National Institutes of Health Clinical Trials Registry in October 2020. There were no date limitations or language restrictions. The following types of studies were included: clinical trials, cohorts, case-control, cross-sectional, clinical series, and case reports. Participants had to meet the following criteria: any sex, any ethnicity, any age, diagnosis of epilepsy, receiving plant-derived, highly purified (> 98% w/w) CBD in a sesame oil-based oral solution for the treatment of seizures. Data extracted from selected records included efficacy, tolerability, and safety outcomes.

RESULTS

Five hundred and seventy records were identified by database and trial register searching. Fifty-seven studies were retrieved for detailed assessment, of which 42 were eventually included for the review. The participants of the studies included patients of both pediatric and adult age. Across the trials, purified CBD was administered at dosages up to 50 mg/kg/day. In a randomized double-blind controlled trial in patients with tuberous sclerosis complex, CBD was associated with a significantly greater percent reduction in seizure frequency than placebo over the treatment period. Open-label studies suggested the effectiveness of CBD in the treatment of children and adults presenting with other epilepsy syndromes than those addressed by regulatory trials, including CDKL5 deficiency disorder and Aicardi, Dup15q, and Doose syndromes, SYNGAP1 encephalopathy, and epilepsy with myoclonic absences. The most common adverse events observed during treatment with CBD included somnolence, decreased appetite, diarrhea, and increased serum aminotransferases.

CONCLUSIONS

The currently available data suggest that response to treatment with a highly purified, plant-derived CBD oil-based solution can be seen in patients across a broad range of epilepsy disorders and etiologies. The existing evidence can provide preliminary support for additional research.

Functional Connectivity Derived From Electroencephalogram in Pharmacoresistant Epileptic Encephalopathy Using Cannabidiol as Adjunctive Antiepileptic Therapy

To explore brain function using functional connectivity and network topology derived from electroencephalogram (EEG) in patients with pharmacoresistant epileptic encephalopathy with cannabidiol as adjunctive antiepileptic treatment. Sixteen epileptic patients participated in the study, six of whom had epileptic encephalopathy with a stable dose of cannabidiol Epidiolex (CBD) as adjunctive therapy. Functional connectivity derived from EEG was analyzed based on the synchronization likelihood (SL). The analysis also included reconstructing graph-theoretic measures from the synchronization matrix. Comparison of functional connectivity data between each pathological group with the control group was carried out using a nonparametric permutation test applied to SL values between pairs of electrodes for each frequency band. To compare the association patterns between graph-theoretical properties of each pathological group with the control group, Z Crawford was calculated as a measure of distance. There were differences between pairs of electrodes in all frequency bands evaluated in encephalopathy epileptic patients with CBD adjunctive therapy compared with the control (p < 0.05, permutation test). In the epileptic encephalopathy group without CBD therapy, the SL values were higher than in the control group for the beta, theta, and delta EEG frequency bands, and lower for the alpha frequency band. Interestingly, patients who had CBD as adjunctive therapy demonstrated greater synchronization for all frequency bands, showing less spatial distribution for alpha frequency compared with the control. When comparing both epileptic groups, those patients who had adjunctive CBD treatment also showed increased synchronization for all frequency bands. In epileptic encephalopathy with adjunctive CBD therapy, the pattern of differences for graph-theoretical measures according to Z Crawford indicated less segregation and greater integration suggesting a trend towards the random organization of the network principally for alpha and beta EEG bands. This exploratory study revealed a tendency to an overconnectivity with a random network topology mainly for fast EEG bands in epileptic encephalopathy patients using CBD adjunctive therapy. It can therefore be assumed that the CBD treatment could be related to inhibition of the transition of the interictal to ictal state and/or to the improvement of EEG organization and brain function.

Cannabinoids: A New Perspective on Epileptogenesis and Seizure Treatment in Early Life in Basic and Clinical Studies

Neural hyperexcitability in the event of damage during early life, such as hyperthermia, hypoxia, traumatic brain injury, status epilepticus, or a pre-existing neuroinflammatory condition, can promote the process of epileptogenesis, which is defined as the sequence of events that converts a normal circuit into a hyperexcitable circuit and represents the time that occurs between the damaging event and the development of spontaneous seizure activity or the establishment of epilepsy. Epilepsy is the most common neurological disease in the world, characterized by the presence of seizures recurring without apparent provocation. Cannabidiol (CBD), a phytocannabinoid derived from the subspecies Cannabis sativa (CS), is the most studied active ingredient and is currently studied as a therapeutic strategy: it is an anticonvulsant mainly used in children with catastrophic epileptic syndromes and has also been reported to have anti-inflammatory and antioxidant effects, supporting it as a therapeutic strategy with neuroprotective potential. However, the mechanisms by which CBD exerts these effects are not entirely known, and the few studies on acute and chronic models in immature animals have provided contradictory results. Thus, it is difficult to evaluate the therapeutic profile of CBD, as well as the involvement of the endocannabinoid system in epileptogenesis in the immature brain. Therefore, this review focuses on the collection of scientific data in animal models, as well as information from clinical studies on the effects of cannabinoids on epileptogenesis and their anticonvulsant and adverse effects in early life.

A Volumetric Absorptive Microsampling Technique to Monitor Cannabidiol Levels in Epilepsy Patients

Purpose: Interest in cannabis-based therapies has recently increased, due to the availability of cannabidiol (CBD) for the treatment of epilepsy without psychoactive effects. Therapeutic drug monitoring can prevent drug interactions and minimize drug toxicity. We evaluated a volumetric absorptive microsampling (VAMS) method combined with LC-MS/MS (liquid chromatography coupled to tandem mass spectrometry) for the quantification of CBD blood levels in patients with refractory epilepsy.

Methods: Prospective observation of patients with Dravet syndrome receiving open-label, add-on GW-purified CBD (Epidyolex^®) at different doses. CBD plasma samples were obtained from venipuncture and LC-MS/MS was used to measure CBD in venous and capillary blood samples collected by VAMS.

Results: We enrolled five patients with a mean age of 13 (range: 4–27) years. CBD levels measured by VAMS on capillary blood did not differ from CBD levels measured in plasma by venipuncture (R² > 0.93).

Conclusion: This proof-of-concept study suggests that VAMS allows monitoring of CBD plasma levels and can offer valuable support for personalized therapy in refractory epilepsy.

Practical use of pharmaceutically purified oral cannabidiol in Dravet syndrome and Lennox-Gastaut syndrome

INTRODUCTION

Pharmaceutically purified oral cannabidiol (CBD) has been recently approved by the US Food and Drug Administration and European Medicines Agency as treatment of seizures associated with Dravet syndrome (DS) and Lennox-Gastaut syndrome (LGS), which are severe and difficult-to-treat developmental and epileptic encephalopathies with onset in early childhood.

AREAS COVERED

This review will critically review the pharmacokinetic properties of CBD, the interactions with antiseizure and non-antiseizure medications, and the main tolerability and safety issues to provide guidance for its use in everyday practice.

EXPERT OPINION

CBD is metabolized in the liver and can influence the activity of enzymes involved in drug metabolism. The best characterized drug-drug interaction is between CBD and clobazam. The most common adverse events include somnolence, gastrointestinal discomfort, and increase in serum transaminases. High-grade purified CBD oral solution represents an effective therapeutic option in patients with DS and LGS. The findings cannot be extrapolated to other cannabis-based products, synthetic cannabinoids for medicinal use and non-medicinal cannabis and CBD derivatives.

Cannabidiol Treatment for Refractory Epilepsies in Pediatrics

Cannabis extracts in oil are becoming increasingly available, and, during the last years, there has been growing public and scientific interest about therapeutic properties of these compounds for the treatment of several neurologic diseases, not just epilepsy. The discovered role of the endocannabinoid system in epileptogenesis has provided the basis to investigate the pharmacological use of exogenously produced cannabinoids, to treat epilepsy. Although, physicians show reluctance to recommend Cannabis extracts given the lack of high-quality safety available data, from literature data cannabidiol (CBD) results to be a promising and safe anticonvulsant drug with low side-effect. In particular, according to early studies, CBD can reduce the frequency of seizures and lead to improvements in quality of life in children affected by refractory epilepsy. So, for these reasons, the detailed study of the interactions between CBD and anticonvulsant drugs (AEDs) administered simultaneously in polytherapy, is arousing increasing interest, to clarify and to assess the incidence of adverse effects and the relation between dose escalation and quality of life measures. To date, in pediatric age, CBD efficacy and safety is not supported by well-designed trials and strong scientific evidence are not available. These studies are either retrospective or small-scale observational and only during the last years Class I evidence data for a pure form of CBD have been available, as demonstrated in placebo-controlled RCTs for patients affected by Lennox-Gastaut syndrome and Dravet syndrome. It is necessary to investigate CBD safety, pharmacokinetics and interaction with other AEDs alongside performing double-blinded placebo-controlled trials to obtain conclusive data on its efficacy and safety in the most frequent epilepsies in children, not just in the epileptic encephalopathy. This review was aimed to revise the available data to describe the scientific evidence for CBD in Pediatric Epilepsies.

Cannabis constituents reduce seizure behavior in chemically-induced and scn1a-mutant zebrafish

Current antiepileptic drugs (AEDs) are undesirable for many reasons including the inability to reduce seizures in certain types of epilepsy, such as Dravet syndrome (DS) where in one-third of patients does not respond to current AEDs, and severe adverse effects that are frequently experienced by patients. Epidiolex, a cannabidiol (CBD)-based drug, was recently approved for treatment of DS. While Epidiolex shows great promise in reducing seizures in patients with DS, it is used in conjunction with other AEDs and can cause liver toxicity. To investigate whether other cannabis-derived compounds could also reduce seizures, the antiepileptic effects of CBD, Δ9-tetrahydrocannabinol (THC), cannabidivarin (CBDV), cannabinol (CBN), and linalool (LN) were compared in both a chemically-induced (pentylenetetrazole, PTZ) and a DS (scn1Lab^-/-) seizure models. Zebrafish (Danio rerio) that were either wild-type (Tupfel longfin) or scn1Lab^-/- (DS) were exposed to CBD, THC, CBDV, CBN, or LN for 24 h from 5 to 6 days postfertilization. Following exposure, total distance traveled was measured in a ViewPoint Zebrabox to determine if these compounds reduced seizure-like activity. Cannabidiol (0.6 and 1 μM) and THC (1 and 4 μM) significantly reduced PTZ-induced total distance moved. At the highest THC concentration, the significant reduction in PTZ-induced behavior was likely the result of sedation as opposed to antiseizure activity. In the DS model, CBD (0.6 μM), THC (1 μM), CBN (0.6 and 1 μM), and LN (4 μM) significantly reduced total distance traveled. Cannabinol was the most effective at reducing total distance relative to controls. In addition to CBD, other cannabis-derived compounds showed promise in reducing seizure-like activity in zebrafish. Specifically, four of the five compounds were effective in the DS model, whereas in the PTZ model, only CBD and THC were, suggesting a divergence in the mode of action among the cannabis constituents.

Therapeutic advances in Dravet syndrome: a targeted literature review

INTRODUCTION

Dravet syndrome (DS), a prototypic developmental and genetic epileptic encephalopathy (DEE), is characterized by an early onset of treatment-refractory seizures, together with impairments in motor control, behavior, and cognition. Even with multiple conventional anti-epileptic drugs, seizures remain poorly controlled, and there has been a considerable unmet need for effective and tolerable treatments.

AREAS COVERED

This targeted literature review aims to highlight recent changes to the therapeutic landscape for DS by summarizing the most up-to-date, evidence-based research, including pivotal data from the clinical development of stiripentol, cannabidiol, and fenfluramine, which are important milestones for DS treatment, together with the latest findings of other pharmacotherapies in development. In phase III, double-blind, placebo-controlled randomized controlled trials stiripentol, cannabidiol, and fenfluramine have shown clinically relevant reductions in convulsive seizure frequency, and are generally well tolerated. Stiripentol was associated with responder rates (greater than 50% reduction in convulsive seizure frequency) of 67%-71%, when added to valproic acid and clobazam; cannabidiol was associated with responder rates of 43%-49% (48%-63% in conjunction with clobazam), and fenfluramine of 54%-68% across studies. Therapies in development include soticlestat, ataluren, verapamil, and clemizole, with strategies to treat the underlying cause of DS, including gene therapy and antisense oligonucleotides beginning to emerge from preclinical studies.

EXPERT OPINION

Despite the challenges of drug development in rare diseases, this is an exciting time for the treatment of DS, with the promise of new efficacious and well-tolerated therapies, which may pave the way for treatment advances in other DEEs.

Cannabidiol Determination on Peripheral Capillary Blood Using a Microsampling Method and Ultra-High-Performance Liquid Chromatography Tandem Mass Spectrometry with On-Line Sample Preparation

The aim of this work is to evaluate volumetric absorptive microsampling (VAMS) from capillary blood as an alternative strategy for therapeutic drug monitoring (TDM) in patients treated with the newly available GW-purified form of cannabidiol (Epidiolex^®). A fast ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) coupled to an online sample preparation system analysis was carried out on a Thermo Scientific Ultimate 3000 LC system coupled to a TSQ Quantiva triple quadrupole for the quantification of cannabidiol (CBD) and, in addition, delta-9-tetrahydrocannabinol (Δ9-THC). After validation using European Medicine Agency (EMA) guidelines the method was applied to samples obtained by finger prick of five pediatric patients treated with Epidiolex^® and the results were compared to those obtained from venous blood and plasma. The method is linear in the range of 1–800 µg/L for both CBD and THC with intra- and inter-day precisions ranging from 5% to 14% and accuracies from −13% to +14% starting from 30 µL of sample. Stability in VAMS is ensured for up to 4 weeks at 25 °C thus allowing simple delivery. There was no difference (p = 0.69) between concentrations of CBD measured from VAMS sampled from capillary or venous blood (range: 52.19–330.14 or 72.15–383.45 µg/L) and those obtained from plasma (range: 64.3–374.09 µg/L) The VAMS-LC-MS/MS method represents a valid alternative strategy for therapeutic drug monitoring of patients treated with Epidiolex^®.

An Open Retrospective Study of a Standardized Cannabidiol Based-Oil in Treatment-Resistant Epilepsy

Introduction:

Cannabidiol (CBD) has antiseizure properties but no psychoactive effects. Randomized controlled trials of an oral, pharmaceutical formulation of highly purified CBD are promising; however, data regarding other formulations are sparse and anecdotal. We evaluated the effectiveness of add-on therapy with a standardized CBD-based oil in treatment-resistant epilepsy (TRE) patients.

Materials and Methods:

An open retrospective study was carried out on patients with refractory epilepsy of different etiology. We reviewed clinical data from medical charts and caregiver's information. Participants received add-on with 24% CBD-based oil, sublingually administered, at the starting dose of 5–10 mg/[kg·day] up to the maximum dose of 50 mg/[kg·day], based on clinical efficacy. Efficacy was evaluated based on patients being seizure free or experiencing at ≥50% improvement on seizure frequency. Tolerability and suspected adverse drug reaction data were also analyzed.

Results:

We included 37 patients (46% female) with a median age of 16.1 (range: 2–54) years. Twenty-two (60%) patients suffered from epileptic encephalopathy, 9 (24%) from focal epilepsy, and 6 (16%) from generalized epilepsy. Mean follow-up duration was 68 (range: 24–72) weeks. The average age at seizure onset was 3.8±2.1 years (range: 7 days–21 years). The median achieved CBD-based oil dose was 4.2±11.4 (range: 0.6–50) mg/[kg·day]. At 40-month follow-up, 7 (19%) patients were seizure free, 27 (73%) reported >50% improvement, 2 (5%) patients reported <50% improvement, and 1 patient discontinued therapy due to lack of efficacy. Weaning from concomitant antiepileptic drugs was obtained after 24 weeks from CBD introduction in 10 subjects. Mild and transitory adverse events, including somnolence or loss of appetite, occurred in nine (25%) patients.

Discussion and Conclusion:

We showed the efficacy of a CBD-based oil formulation with few significant side effects in patients with TRE of various etiologies.

Cannabis, More Than the Euphoria: Its Therapeutic Use in Drug-Resistant Epilepsy

A significant number of epilepsy patients are refractory to conventional antiepileptic drugs. These patients experience considerable neurocognitive impairments that impact their quality of life and ability to function independently. This need for alternative treatment has generated increased interest in cannabis use as a therapeutic option in these patients. This review seeks to analyze data presented on the pharmacology, safety, and efficacy of cannabis use in patients with drug-resistant epilepsy (DRE) and to propose any future recommendations regarding its use. PubMed was used to retrieve all published studies and articles which evaluated the use of cannabis in epilepsy. The two foremost phytocannabinoids of cannabis showing anticonvulsant properties are tetrahydrocannabinol (THC) and cannabidiol (CBD). Due to the psychoactive properties of THC, most studies focused on CBD use in these patients. The use of CBD as an adjunct resulted in decreased seizure frequency, and secondary benefits observed included improvement in mood, alertness and sleep. Adverse events (AEs) reported were drowsiness, diarrhea, increased transaminases and worsening of seizures. It can safely be concluded that there is a significant benefit in DRE patients using CBD as adjunctive therapy. However, further controlled and adequately powered studies are needed to assess the pharmacokinetics and impact of the long-term use of cannabis.

Adjunctive Cannabidiol in Patients with Dravet Syndrome: A Systematic Review and Meta-Analysis of Efficacy and Safety

BACKGROUND

Dravet syndrome (DS) is one of the most severe forms of drug-resistant epilepsy and available interventions fail to control seizures in most patients. Cannabidiol (CBD) is the first in a new class of antiepileptic drugs with a distinctive chemical structure and mechanism of action.

OBJECTIVE

The aim of this systematic review was to evaluate the efficacy and safety of CBD as adjunctive treatment for seizures in patients with DS using meta-analytical techniques.

METHODS

We searched for randomized, placebo-controlled, single- or double-blinded trials. Main outcomes included ≥ 50% reduction in baseline convulsive seizure frequency and the incidence of treatment withdrawal and adverse events (AEs). Risk ratios (RRs) with 95% confidence intervals (95% CIs) were estimated through the inverse variance method.

RESULTS

Three trials were included involving 359 participants, 228 for CBD and 131 for placebo groups. In all trials, the active treatment was a plant-derived pharmaceutical formulation of purified CBD oral solution. The pooled RR for 50% response during the treatment was 1.69 (95% CI 1.21-2.36; p = 0.002). Across the trials, treatment was discontinued in 20 (9.0%) and 3 (2.3%) cases in the add-on CBD and placebo groups, respectively; the RR for CBD withdrawal was 3.12 (95% CI 1.07-9.10; p = 0.037). The RR to develop any AE during add-on CBD treatment was 1.06 (95% CI 0.87-1.28; p = 0.561). AEs significantly associated with adjunctive CBD were somnolence, decreased appetite, diarrhea, and increased serum aminotransferases.

CONCLUSIONS

Adjunctive CBD resulted in a greater reduction in convulsive seizure frequency than placebo and a higher rate of AEs in patients with DS presenting with seizures uncontrolled by concomitant antiepileptic therapy.

Cannabinoids in the Treatment of Epilepsy: Current Status and Future Prospects

Cannabidiol (CBD) is one of the prominent phytocannabinoids found in Cannabis sativa, differentiating from Δ9-tetrahydrocannabinol (THC) for its non-intoxicating profile and its antianxiety/antipsychotic effects. CBD is a multi-target drug whose anti-convulsant properties are supposed to be independent of endocannabinoid receptor CB1 and might be related to several underlying mechanisms, such as antagonism on the orphan GPR55 receptor, regulation of adenosine tone, activation of 5HT1A receptors and modulation of calcium intracellular levels. CBD is a lipophilic compound with low oral bioavailability (6%) due to poor intestinal absorption and high first-pass metabolism. Its exposure parameters are greatly influenced by feeding status (ie, high fat-containing meals). It is mainly metabolized by cytochrome P 450 (CYP) 3A4 and 2C19, which it strongly inhibits. A proprietary formulation of highly purified, plant-derived CBD has been recently licensed as an adjunctive treatment for Dravet syndrome (DS) and Lennox-Gastaut syndrome (LGS), while it is being currently investigated in tuberous sclerosis complex. The regulatory agencies' approval was granted based on four pivotal double-blind, placebo-controlled, randomized clinical trials (RCTs) on overall 154 DS patients and 396 LGS ones, receiving CBD 10 or 20 mg/kg/day BID as active treatment. The primary endpoint (reduction in monthly seizure frequency) was met by both CBD doses. Most patients reported adverse events (AEs), generally from mild to moderate and transient, which mainly consisted of somnolence, sedation, decreased appetite, diarrhea and elevation in aminotransferase levels, the last being documented only in subjects on concomitant valproate therapy. The interaction between CBD and clobazam, likely due to CYP2C19 inhibition, might contribute to some AEs, especially somnolence, but also to CBD clinical effectiveness. Cannabidivarin (CBDV), the propyl analogue of CBD, showed anti-convulsant properties in pre-clinical studies, but a plant-derived, purified proprietary formulation of CBDV recently failed the Phase II RCT in patients with uncontrolled focal seizures.