A perspective on cannabinoids for treating epilepsy: Do they really change the landscape?

With the licensing of cannabidiol for drug resistant seizures in Dravet and Lennox Gastaut syndromes in the United states in 2018, interest in the potential for cannabis-based-medicinal products to meet currently unmet needs for people with epilepsy continues to grow. This review summarizes current knowledge and discusses the implications for future research and practice. Both cannabidiol and tetrahydrocannabinol, the main components, have been extensively studied in animal models, with multimodal mechanisms of action proposed. Only pure cannabidiol formulations have been rigorously evaluated in controlled trials thus far, with modest but significant improvements in motor seizures. Adverse effects include diarrhoea, somnolence and reduced appetite, with mostly acceptable tolerability, but a not insignificant (up to 1 in 23) risk of serious adverse events. Recognized drug interactions include with valproate (increased risk of hepatotoxicity) and clobazam (contributing to somnolence, increased secretions, probably chest infections, and potentially efficacy). Whilst there is public (and producer) interest in products also containing tetrahydrocannabinol, clinicians have justifiable concerns about exposing a group already vulnerable to mental health and neurobehavioural comorbidities to the associated additional risks in these domains. Artisanal preparations, with often inconsistent/unknown constituents are frequently used but not recommended. A gulf exists between the actual evidence, including a lack of comparative studies and public beliefs, fuelled by media and anecdote. Continued education of the public, policymakers, researchers and healthcare providers about what is and isn't yet known, together with on-going good quality research is essential to mitigate against future potential risks, particularly in relation to vulnerable populations. This article is part of the special issue entitled 'New Epilepsy Therapies for the 21st Century - From Antiseizure Drugs to Prevention, Modification and Cure of Epilepsy'.

Changes in functional brain network topology after successful and unsuccessful corpus callosotomy for Lennox-Gastaut Syndrome

Corpus callosotomy (CC) is an effective palliative surgical treatment for patients with Lennox-Gastaut Syndrome (LGS). However, research on the long-term functional effects of CC is sparse. We aimed to investigate these effects and their associated clinical conditions over the two years after CC. Long-term clinical EEG recordings of 30 patients with LGS who had good and bad seizure outcome after CC were collected and retrospectively studied. It was found that CC caused brain network 'hubs' to shift from paramedian to lateral regions in the good-recovery group, which reorganized the brain network into a more homogeneous state. We also found increased local clustering coefficients in patients with bad outcomes and decreases, implying enhanced network integration, in patients with good outcomes. The small worldness of brain networks in patients with good outcomes increased in the two years after CC, whereas it decreased in patients with bad outcomes. The covariation of small-worldness with the rate of reduction in seizure frequency suggests that this can be used as an indicator of CC outcome. Local and global network changes during the long-term state might be associated with the postoperative recovery process and could serve as indicators for CC outcome and long-term LGS recovery.

Lennox-Gastaut syndrome in adulthood: Long-term clinical follow-up of 38 patients and analysis of their recorded seizures

Lennox-Gastaut syndrome (LGS) is a severe epileptic encephalopathy with childhood onset that usually continues through adolescence and into adulthood. In the long term, patients with this condition still have intractable seizures, intellectual disability, behavioral problems, and physical comorbidities. The aim of this study was to describe the clinical and EEG characteristics of a group of adults with Lennox-Gastaut syndrome. We identified 38 (22 females, 16 males) patients with LGS older than age 18years at their last evaluation, with mean age of 43.3±10.6years. Median follow-up was 14.4years (range: 2-40). All of our patients had 3 or more seizure types during their clinical history. The most prevalent seizure types at follow-up were atypical absences (28/38), tonic (28/38), generalized tonic-clonic (17/38), focal (11/38), and myoclonic seizures (9/38). All patients had drug-resistant seizures. Besides epilepsy, intellectual disability and behavioral problems were prominent features. Surprisingly, paroxysmal nonepileptic seizures were reported in 3 patients. Our observations confirm the poor outcome of Lennox-Gastaut syndrome through adulthood, regardless of age at seizure onset, etiology, and history of previous West syndrome.

Budget impact analysis of antiepileptic drugs for Lennox-Gastaut syndrome

BACKGROUND

In October 2011, clobazam was FDA-approved for adjunctive treatment of seizures associated with Lennox-Gastaut syndrome (LGS), a debilitating childhood epilepsy characterized by drop attacks, for patients 2 years and older.

OBJECTIVE

To assess the budget impact of adding clobazam to an antiepileptic drug (AED) portfolio containing topiramate, lamotrigine, and rufinamide in a hypothetical, 100,000-member commercially insured health plan.

METHODS

Patient characteristics and AED efficacy (decrease in drop-seizure frequency) were modeled with clinical data. Medical costs were derived from administrative claims data from a large U.S. managed health plan, with the assumption that 2.3% of drop seizures required medical care. Two-year budget impact was measured. Results were expressed as the overall difference in costs (medical and pharmacy) to a health plan and cost per member per month (PMPM) after addition of clobazam. Analyses of alternative scenarios were performed.

RESULTS

With the assumption that 0.04% of the plan population had LGS, adding clobazam to the formulary resulted in cost savings of $98,059 in year 1 and $131,690 in year 2 (savings of $0.08 and $0.11 PMPM, respectively). Analyses of alternative scenarios with lower seizure rates upon discontinuation or greater long-term efficacy for lamotrigine and topiramate did not substantially alter conclusions. The assumption that fewer drop seizures required medical care resulted in a savings of approximately $5,000 per year with clobazam, which suggested that medically attended drop seizures drive costs.

CONCLUSIONS

Medically attended drop seizures are a major cost driver for LGS patients. Adding clobazam to a health plan formulary can have a positive overall budget impact through decreased medical costs associated with drop seizures.