Cannabidiol in conjunction with clobazam: analysis of four randomized controlled trials

CBD in the Treatment of Epilepsy

It has been several years since highly purified cannabidiol (CBD) was registered as a medication that can be used in children of at least 2 years of age to treat different types of seizures related to Lennox-Gastaut syndrome (LGS), Dravet syndrome (DS), and more recently tuberous sclerosis complex (TSC). During this time, 39 randomized clinical trials (RCTs) and 13 meta-analyses on the efficacy and safety of CBD treatment have been published. Each of the meta-analyses had its own criteria for the RCTs' inclusion and, therefore, slightly different interpretations of the analyzed data. Each of them contributed in its own way to the understanding of CBD pharmacology, mechanisms of therapeutic action, development of adverse reactions, and drug-drug interactions. Hence, it seemed reasonable to gather the most relevant data in one article and present all the current knowledge on the use of CBD in epilepsy. The results of the 13 meta-analyses presented herein confirmed the effectiveness and safety of CBD in children and adolescents with DREs. In adults, reliable conclusions cannot be drawn due to insufficient data.

Comparative efficacy and safety of stiripentol, cannabidiol and fenfluramine as first-line add-on therapies for seizures in Dravet syndrome: A network meta-analysis

OBJECTIVES

Stiripentol, fenfluramine, and cannabidiol are licensed add-on therapies to treat seizures in Dravet Syndrome (DS). There are no direct or indirect comparisons assessing their full licensed dose regimens, across different jurisdictions, as first-line add-on therapies in DS.

METHODS

We conducted a systematic review and frequentist network meta-analysis (NMA) of randomized controlled trial (RCT) data for licensed add-on DS therapies. We compared the proportions of patients experiencing: reductions from baseline in monthly convulsive seizure frequency (MCSF) of ≥50% (clinically meaningful), ≥75% (profound), and 100% (seizure-free); serious adverse events (SAEs); discontinuations due to AEs.

RESULTS

We identified relevant data from two placebo-controlled RCTs for each drug. Stiripentol 50 mg/kg/day and fenfluramine 0.7 mg/kg/day had similar efficacy in achieving ≥50% (clinically meaningful) and ≥75% (profound) reductions from baseline in MCSF (absolute risk difference [RD] for stiripentol versus fenfluramine 1% [95% confidence interval: -20% to 22%; p = 0.93] and 6% [-15% to 27%; p = 0.59], respectively), and both were statistically superior (p < 0.05) to licensed dose regimens of cannabidiol (10 or 20 mg/kg/day, with/irrespective of clobazam) for these outcomes. Stiripentol was statistically superior in achieving seizure-free intervals compared to fenfluramine (RD = 26% [CI: 8% to 44%; p < 0.01]) and licensed dose regimens of cannabidiol. There were no significant differences in the proportions of patients experiencing SAEs. The risk of discontinuations due to AEs was lower for stiripentol, although the stiripentol trials were shorter.

SIGNIFICANCE

This NMA of RCT data indicates stiripentol, as a first-line add-on therapy in DS, is at least as effective as fenfluramine and both are more effective than cannabidiol in reducing convulsive seizures. No significant difference in the incidence of SAEs between the three add-on agents was observed, but stiripentol may have a lower risk of discontinuations due to AEs. These results may inform clinical decision-making and the continued development of guidelines for the treatment of people with DS.

PLAIN LANGUAGE SUMMARY

This study compared three drugs (stiripentol, fenfluramine, and cannabidiol) used alongside other medications for managing seizures in a severe type of epilepsy called DS. The study found that stiripentol and fenfluramine were similarly effective in reducing seizures and both were more effective than cannabidiol. Stiripentol was the best drug for stopping seizures completely based on the available clinical trial data. All three drugs had similar rates of serious side effects, but stiripentol had a lower chance of being stopped due to side effects. This information can help guide treatment choices for people with DS.

Cannabidiol: metabolism and clinical efficacy in epileptic patients

INTRODUCTION

The landscape of epilepsy treatment has undergone a significant transformation with the emergence of cannabidiol as a potential therapeutic agent. Epidiolex, a pharmaceutical formulation of highly purified CBD, garnered significant attention not just for its therapeutic potential but also for being the first cannabis-derived medication to obtain approval from regulatory bodies.

AREA COVERED

In this narrative review the authors explore the intricate landscape of CBD as an antiseizure medication, deepening into its pharmacological mechanisms and clinical trials involving various epileptic encephalopathies. This exploration serves as a comprehensive guide, shedding light on a compound that holds promise for individuals contending with the significant challenges of drug-resistant epilepsy.

EXPERT OPINION

Rigorous studies highlight cannabidiol's efficacy, safety profile, and potential cognitive benefits, warranting further exploration for its approval in various drug-resistant epilepsy forms. As a promising therapeutic option, cannabidiol not only demonstrates efficacy in seizure control but also holds the potential for broader enhancements in the quality of life, especially for patients with epileptic encephalopathies.

Challenges, unmet needs and future directions - a critical evaluation of the clinical trial landscape in schizophrenia research

INTRODUCTION

Developing novel antipsychotic mechanisms of action and repurposing established compounds for the treatment of schizophrenia is of utmost importance to improve relevant symptom domains and to improve the risk/benefit ratio of antipsychotic compounds. Novel trial design concepts, pathophysiology-based targeted treatment approaches, or even the return to old values may improve schizophrenia outcomes in the future.

AREAS COVERED

In this review of the clinical trial landscape in schizophrenia, we present an overview of the challenges and gaps in current clinical trials and elaborate on potential solutions to improve the outcomes of people with schizophrenia.

EXPERT OPINION

The classic parallel group design may limit substantial advantages in drug approval or repurposing. Collaborative approaches between regulatory authorities, industry, academia, and funding agencies are needed to overcome barriers in clinical schizophrenia research to allow for meaningful outcome improvements for the patients.

Emerging Therapeutic Potential of Cannabidiol (CBD) in Neurological Disorders: A Comprehensive Review

Cannabidiol (CBD), derived from Cannabis sativa, has gained remarkable attention for its potential therapeutic applications. This thorough analysis explores the increasing significance of CBD in treating neurological conditions including epilepsy, multiple sclerosis, Parkinson's disease, and Alzheimer's disease, which present major healthcare concerns on a worldwide scale. Despite the lack of available therapies, CBD has been shown to possess a variety of pharmacological effects in preclinical and clinical studies, making it an intriguing competitor. This review brings together the most recent findings on the endocannabinoid and neurotransmitter systems, as well as anti-inflammatory pathways, that underlie CBD's modes of action. Synthesized efficacy and safety assessments for a range of neurological illnesses are included, covering human trials, in vitro studies, and animal models. The investigation includes how CBD could protect neurons, control neuroinflammation, fend off oxidative stress, and manage neuronal excitability. This study emphasizes existing clinical studies and future possibilities in CBD research, addressing research issues such as regulatory complications and contradicting results, and advocates for further investigation of therapeutic efficacy and ideal dose methodologies. By emphasizing CBD's potential to improve patient well-being, this investigation presents a revised viewpoint on its suitability as a therapeutic intervention for neurological illnesses.

Retrospective chart review study of use of cannabidiol (CBD) independent of concomitant clobazam use in patients with Lennox-Gastaut syndrome or Dravet syndrome

PURPOSE

This retrospective chart review study (GWEP20052) evaluated plant-derived highly purified cannabidiol (CBD; Epidyolex®; 100 mg/mL oral solution) use without clobazam as add-on therapy in patients aged ≥2 years with Lennox-Gastaut syndrome (LGS) or Dravet syndrome (DS) enrolled in a European Early Access Program.

METHODS

Data were extracted from patient charts covering a period starting 3 months before CBD treatment and concluding after 12 months of CBD treatment, or sooner if a patient discontinued CBD or started clobazam.

RESULTS

Of 114 enrolled patients, data were available for 107 (92 LGS, 15 DS) who received CBD without clobazam for ≥3 months. Mean age: 14.5 (LGS) and 10.5 (DS) years; female: 44% (LGS) and 67% (DS). Mean time-averaged CBD dose: 13.54 (LGS) and 11.56 (DS) mg/kg/day. Median change from baseline in seizure frequency per 28 days over 3-month intervals varied from -6.2% to -20.9% for LGS and 0% to -16.7% for DS. Achievement of ≥50% reduction in drop (LGS) or convulsive (DS) seizures at 3 and 12 months: LGS, 19% (n = 69) and 30% (n = 53); DS, 21% (n = 14) and 13% (n = 8). Retention on CBD without clobazam (enrolled set): 94%, 80%, 69%, and 63% at 3, 6, 9, and 12 months. Adverse event (AE) incidence was 31%, most commonly somnolence, seizure, diarrhea, and decreased appetite. Two patients discontinued CBD owing to AEs, and four patients with LGS experienced elevated liver enzymes.

CONCLUSION

Results support favorable effectiveness and retention of CBD without concomitant clobazam for up to 12 months in clinical practice.

The cenobamate-clobazam interaction- evidence of synergy in addition to pharmacokinetic interaction

OBJECTIVES

Report insights into the pharmacokinetic and pharmacodynamic interaction between cenobamate (CNB) and clobazam (CLB), derived from data in patients enrolled at our center in a global multicenter open-label safety study of CNB.

MATERIALS & METHODS

Patients in this study either took CLB at baseline (n = 6) or had CLB added after CNB titration to maximal dose (n = 5) in addition to other antiseizure medications. Clobazam was always administered as a single bedtime dose. Random serum concentrations of CLB and N-desmethylclobazam (N-CLB) were obtained.

RESULTS

Baseline daily CLB doses were 20-50 mg. Sedation began in the six baseline CLB patients at CNB doses of 25-100 mg. The N-CLB/ CLB ratio increased proportionally to the CNB dose. CLB was stopped in all six patients, five of whom were ≥50% responders. Seizure control deteriorated after stopping CLB, with only one remaining responder. Clobazam was restarted at 5 mg/d in five of the six patients. At the last follow-up, four of these patients were continuing CLB; two were seizure-free and 2 were ≥50% responders. Among the five patients that added 5 mg/d CLB de novo, three were responders. All patients were still on CNB at the end of the study.

DISCUSSION

Data suggest starting CLB dose reduction at CNB doses of 25-100 mg/d. Due to possible synergy, the addition of low-dose CLB could be considered in patients with incomplete response to CNB.

Real-world, long-term evaluation of the tolerability and therapy retention of Epidiolex® (cannabidiol) in patients with refractory epilepsy

OBJECTIVE

Epidiolex® (CBD) is FDA-approved for seizures associated with Lennox-Gastaut syndrome (LGS), Dravet syndrome (DS), and tuberous sclerosis complex (TSC). Phase III studies suggest that certain adverse effects (AEs), possibly linked to pharmacokinetic/pharmacodynamic (PK/PD) interactions may be therapy-limiting. We sought to identify these factors that contribute to treatment success and retention of therapy.

METHODS

A single-center, retrospective review of patients with refractory epilepsy taking Epidiolex® was performed. Kaplan-Meier analysis was performed to describe Epidiolex® retention, as a measure of overall effectiveness.

RESULTS

One hundred and twelve patients were screened; 4 were excluded due to loss to follow-up or never starting Epidiolex®. Of 108 patients, mean age was 20.3 years (13.1, range 2 to 63), and 52.8% were female. Mean initial and maintenance doses were 5.3 mg/kg/day (1.3) and 15.3 mg/kg/day (5.8), respectively. At the final evaluation, 75% of patients remained on Epidiolex®. The 25th percentile for discontinuation was 19 months. 46.3% of patients experienced at least one treatment-emergent adverse effect (TEAE) with 14.5% d/c Epidiolex® due to treatment emerging adverse effects (TEAE). The most common reasons for discontinuation were lack of efficacy (37%), increased seizure activity (22%), worsened behavior (22%), and sedation (22%). One out of 27 discontinuations was due to liver function test (LFT) elevations (3.7%). At initiation, 47.2% were concurrently taking clobazam, and 39.2% of those patients had an initial clobazam dose decrease. 53% of patients were able to either discontinue or lower the dose of at least one other antiseizure medication.

SIGNIFICANCE

Epidiolex® is generally well-tolerated and the majority continued long-term treatment. Patterns of adverse effects were similar to clinical trials, however gastrointestinal complaints, and significant LFT elevations were less common. Our data suggest most patients discontinue within the first several months of treatment and suggest that further studies designed to evaluate early identification and potential mitigation of adverse effects and including drug interactions are warranted.

Therapeutic and clinical foundations of cannabidiol therapy for difficult-to-treat seizures in children and adults with refractory epilepsies

Novel and effective antiseizure medications are needed to treat refractory and rare forms of epilepsy. Cannabinoids, which are obtained from the cannabis plant, have a long history of medical use, including for neurologic conditions. In 2018, the US Food and Drug Administration approved the first phytocannabinoid, cannabidiol (CBD, Epidiolex), which is now indicated for severe seizures associated with three rare forms of developmental and epileptic encephalopathy: Dravet syndrome, Lennox-Gastaut syndrome, and tuberous sclerosis complex. Compelling evidence supports the efficacy of CBD in experimental models and patients with epilepsy. In randomized clinical trials, highly-purified CBD has demonstrated efficacy with an acceptable safety profile in children and adults with difficult-to-treat seizures. Although the underlying antiseizure mechanisms of CBD in humans have not yet been elucidated, the identification of novel antiseizure targets of CBD preclinically indicates multimodal mechanisms that include non-cannabinoid pathways. In addition to antiseizure effects, CBD possesses strong anti-inflammatory and neuroprotective activities, which might contribute to protective effects in epilepsy and other conditions. This article provides a succinct overview of therapeutic approaches and clinical foundations of CBD, emphasizing the clinical utility of CBD for the treatment of seizures associated with refractory and rare epilepsies. CBD has shown to be a safe and effective antiseizure medicine, demonstrating a broad spectrum of efficacy across multiple seizure types, including those associated with severe epilepsies with childhood onset. Despite such promise, there are many perils with CBD that hampers its widespread use, including limited understanding of pharmacodynamics, limited exposure-response relationship, limited information for seizure freedom with continued use, complex pharmacokinetics with drug interactions, risk of adverse effects, and lack of expert therapeutic guidelines. These scientific issues need to be resolved by further investigations, which would decide the unique role of CBD in the management of refractory epilepsy.

Clinical efficacy and safety of cannabidiol for pediatric refractory epilepsy indications: A systematic review and meta-analysis

Antiseizure medications (ASMs) are the mainstay for the treatment of seizure disorders. However, about one-third of people with epilepsy remain refractory to current ASMs. Cannabidiol (CBD) has recently been approved as ASM for three refractory epilepsy syndrome indications in children and adults. In this study, we evaluated the overall clinical potential of an oral CBD to treat refractory epilepsy in patients with Dravet syndrome (DS), Lennox-Gastaut syndrome (LGS), and tuberous sclerosis complex (TSC) through a systematic review and meta-analysis. A comprehensive search of databases was conducted, including randomized controlled trials (RCTs) assessing the effect of CBD in epilepsy patients. The review was conducted as per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The review focused on RCTs involving patients receiving highly purified oral CBD (Epidiolex, 10 to 50 mg/kg/day) for up to 16 weeks. A subgroup analysis by syndrome and CBD with or without concomitant clobazam was conducted. The key outcomes were reduction in seizure frequency, differences in 50% responder rates, adverse events, and interactions with clobazam as co-therapy. Odds ratio (OR) with 95% confidence interval (CI) were estimated. Of 1183 articles screened, we included 6 RCTs meeting our eligibility criteria. All studies were considered to have a low risk of bias. In the pooled analysis, CBD treatment was found to be more efficacious compared to placebo (OR = 2.45, 95% CI =1.81-3.32, p < 0.01). Subgroup analysis by syndrome demonstrated the odds of ≥50% reduction in seizures with CBD treatment in patients with DS (OR = 2.26, 95% CI:1.38-3.70), LGS (OR = 2.98, 95% CI:1.83-4.85) and TSC (OR = 1.99, 95% CI = 1.06-3.76). Compared with placebo, CBD was associated with increased adverse events (OR = 1.81, 95% CI = 1.33-2.46) such as diarrhea, somnolence, and sedation, and any serious adverse events (OR = 2.86, 95% CI = 1.63-5.05). Other factors, including dosage and clobazam co-therapy, were significantly associated with a greater effect on seizure control and side effects of CBD. In conclusion, the study shows that CBD is highly efficacious both as standalone and adjunct therapy with clobazam for controlling seizures in DS, LGS, and TSC conditions while limiting side effects. Further pharmacodynamic investigation of CBD actions, drug interaction assessments, and therapeutic management guidelines are warranted.

Cannabis-based magistral formulation is highly effective as an adjuvant treatment in drug-resistant focal epilepsy in adult patients: an open-label prospective cohort study

INTRODUCTION

The safety and efficacy of a formulation high in cannabidiol (CBD) and low in ∆⁹-tetrahydrocannabinol (THC) to treat drug-resistant epilepsy have been examined previously in children, but not in adult population. The aim of this study was to evaluate whether CBD-rich oil, as an add-on treatment to conventional antiepileptic drugs, was effective, safe, and well-tolerated in adults with drug-resistant focal epilepsy (DRFE).

METHODS

An open-label, prospective cohort, single-center in adult patients with DRFE, were receiving stable doses of antiepileptic drugs (AEDs). A cannabis based-magistral formulation (CBMF) (100 mg/ml CBD and THC <1.9 mg/ml) was administrated 0.1 ml sublingually every 12 hours, up-titrated weekly. The primary outcome was to establish a reduction in seizures frequency >50% at 12 weeks. Adverse-drug reactions monitoring was done. p-value <0.05 was statistically significant.

RESULTS

Between August 2020 and July 2022, 44 (38.6%) patients completed >3 months of follow-up. The median daily dose of CBD was 200 mg, that of THC was 4 mg, and that of CBD per kilogram of weight was 3.7 mg. The median number of seizures per month before CBD treatment was 11, and after CBD treatment was 2.5 (p<0.001). A reduction in seizures >50% at 12 week was achieved in 79.5% of the patients. The median percentage change in seizure frequency per month was 84.1% at 12 weeks. Five patients reported any adverse-drug reactions.

CONCLUSION

The CBMF is a highly effective and safety therapy to treat adult patients with DRFE. The reduction in seizures frequency is maintained over time.

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.

Safety and efficacy of cannabidiol-cannabidiolic acid rich hemp extract in the treatment of refractory epileptic seizures in dogs

The use of cannabidiol (CBD) in childhood refractory seizures has become a common therapeutic approach for specific seizure disorders in human medicine. Similarly, there is an interest in using CBD, cannabidiolic acid (CBDA) or cannabinoid-rich hemp products in the treatment of idiopathic epilepsy in dogs. We aimed to examine a small cohort in a pilot investigation using a CBD and CBDA-rich hemp product for the treatment of refractory epileptic seizures in dogs. Fourteen dogs were examined in a 24-week randomized cross-over study being provided placebo or CBD/CBDA-rich hemp extract treatment at 2 mg/kg orally every 12 h for each 12-week arm of the study. Serum chemistry, complete blood counts, serum anti-seizure medication (ASM) concentrations and epileptic seizure frequency were followed over both arms of the cross-over trial. Results demonstrated that besides a mild increase in alkaline phosphatase, there were no alterations observed on routine bloodwork at 2, 6, and 12 weeks during either arm of the study. Epileptic seizure frequency decreased across the population from a mean of 8.0 ± 4.8 during placebo treatment to 5.0 ± 3.6 with CBD/CBDA-rich hemp extract (P = 0.02). In addition, epileptic seizure event days over the 12 weeks of CBD/CBDA-rich hemp treatment were 4.1 ± 3.4, which was significantly different than during the 12 weeks of placebo treatment (5.8 ± 3.1; P =0.02). The number of dogs with a 50% reduction in epileptic activity while on treatment were 6/14, whereas 0/14 had reductions of 50% or greater while on the placebo (P = 0.02). No differences were observed in serum zonisamide, phenobarbital or bromide concentrations while on the treatment across groups. Adverse events were minimal, but included somnolence (3/14) and transient increases in ataxia (4/14) during CBD/CBDA-rich hemp extract treatment; this was not significantly different from placebo. This further indicates that providing CBD/CBDA-rich hemp extract during refractory epilepsy (only partially responsive to ASM), in conjunction with other ASM appears safe. Based on this information, the use of 2 mg/kg every 12 h of a CBD/CBDA-rich hemp extract can have benefits in reducing the incidence of epileptic seizures, when used concurrently with other ASMs.

Cannabidiol and epilepsy in Brazil: a current review

BACKGROUND

Cannabidiol (CBD) has become a promising therapeutic option in the treatment of epilepsy. Recent studies provide robust evidence that CBD is effective and safe. Limitations in current knowledge and regulatory issues still limit CBD use. CBD use regarding epilepsy types still lacks clear guidelines.

OBJECTIVE

To critically review the main current pharmacological features and clinical issues regarding CBD use in epilepsy, to provide current regulatory background regarding CBD use in Brazil, and to suggest a practical CBD therapeutic guide in Brazil.

METHODS

Non-systematic literature review (up to February 2022) of current concepts of CBD and epilepsy, including the authors' personal experience.

RESULTS

Five pivotal trials have led to CBD approval as an adjunctive treatment for Dravet and Lennox-Gastaut syndromes, and for the tuberous sclerosis complex. Efficacy of CBD in other drug-resistant epilepsies remains not completely understood. CBD adverse event profile and drug interactions are better understood. CBD is well tolerated. In Brazil, CBD is not classified as a medication, but as a product subject to a distinct regulatory legislation. CBD is still not offered by the National Brazilian health system, but can be purchased in authorized pharmacies or imported under prescription and signed informed consent.

CONCLUSION

CBD is a recognized novel treatment for epilepsy. Future well-designed studies and public health strategies are needed to offer widespread access to CBD, and to improve the quality of life of people living with epilepsy in Brazil.

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.