The effect of mTOR inhibition on obstructive hydrocephalus in patients with tuberous sclerosis complex (TSC) related subependymal giant cell astrocytoma (SEGA).

PURPOSE: Mammalian target of rapamycin inhibitors (mTORi) are known to effectively reduce the size of subependymal giant cell astrocytomas (SEGAs), which are benign brain lesions associated with Tuberous Sclerosis Complex (TSC) that commonly cause obstructive hydrocephalus (OH). This retrospective case series reviews an institutional experience of the effect of mTORi on OH in patients with TSC-related SEGA. METHODS: Thirteen of 16 identified patients with TSC-related SEGA treated with mTORi from October 2007 to December 2018 were included. Serial magnetic resonance imaging (MRI) and clinical charts were reviewed to correlate symptoms and signs of increased intracranial pressure (iICP) with ventriculomegaly on MRI. A proposed ventriculomegaly scale was used: none (< 7 mm), mild (7-10 mm), moderate (11-30 mm), and severe (> 30 mm). OH was defined as moderate or severe ventriculomegaly, based on the largest measurement. RESULTS: Patients' median age at start of mTORi was 13 (6-17) years and five (38%) patients were female. Eight patients had OH at the time of mTORi initiation, five of whom were asymptomatic. Six patients had improvement of hydrocephalus on serial MRI imaging with mTORi therapy, while seven patients had no change based on the ventriculomegaly scale used. All three patients who presented with symptoms of iICP and had OH also had papilledema. None had worsening of hydrocephalus or required shunt placement. Out of five patients with symptoms of iICP, four avoided surgery. CONCLUSION: Most patients had asymptomatic OH at the time of diagnosis, and ventricular enlargement was not correlated with iICP symptoms. mTORi was successful for treatment of OH from TSC-related SEGA, even in the setting of acute symptoms of iICP.

Barriers in accessing medical cannabis for children with drug-resistant epilepsy in Canada: A qualitative study.

INTRODUCTION: The use of medical cannabis to treat drug-resistant epilepsy in children is increasing; however, there has been limited study of the experiences of parents with the current system of accessing medical cannabis for their children. METHODS: In this qualitative study, we used a patient-centered access to care framework to explore the barriers faced by parents of children with drug-resistant epilepsy when trying to access medical cannabis in Canada. We conducted semistructured interviews with 19 parents to elicit their experiences with medical cannabis. We analyzed the data according to five dimensions of access, namely approachability, acceptability, availability, affordability, and appropriateness. RESULTS: Parents sought medical cannabis as a treatment because of a perceived unmet need stemming from the failure of antiepileptic drugs to control their children's seizures. Medical cannabis was viewed as an acceptable treatment, especially compared with adding additional antiepileptic drugs. After learning about medical cannabis from the media, friends and family, or other parents, participants sought authorization for medical use. However, most encountered resistance from their child's neurologist to discuss and/or authorize medical cannabis, and many parents experienced difficulty in obtaining authorization from a member of the child's existing care team, leading them to seek authorization from a cannabis clinic. Participants described spending up to $2000 per month on medical cannabis, and most were frustrated that it was not eligible for reimbursement through public or private insurance programs. CONCLUSIONS: Parents pursue medical cannabis as a treatment for their children's drug-resistant epilepsy because of a perceived unmet need. However, parents encounter barriers in accessing medical cannabis in Canada, and strategies are needed to ensure that children using medical cannabis receive proper care from healthcare professionals with training in epilepsy care, antiepileptic drugs, and medical cannabis.

Cannabis-based products for pediatric epilepsy: A systematic review.

OBJECTIVE: To assess the benefits and harms of cannabis-based products for pediatric epilepsy. METHODS: We identified in this living systematic review randomized controlled trials (RCTs) and nonrandomized studies (NRSs) involving children with epilepsy treated with cannabis-based products. We searched MEDLINE, Embase, PsycINFO, Cochrane Library, and gray literature (April 25, 2018). The primary outcome was seizure freedom; secondary outcomes were seizure frequency (total, ≥50% reduction), quality of life, sleep, status epilepticus, death, gastrointestinal adverse events, and visits to the emergency room. Data were pooled by random-effects meta-analysis. Risk of bias was assessed for each study, and GRADE was used to assess the quality of evidence for each outcome. RESULTS: Four RCTs and 19 NRSs were included, primarily involving cannabidiol. All RCTs were at low risk of bias, whereas all NRSs were at high risk. Among RCTs, there was no statistically significant difference between cannabidiol and placebo in seizure freedom (relative risk [RR] = 6.77, 95% confidence interval [CI] = 0.36-128.38; 1 RCT), quality of life (mean difference = 0.6, 95% CI = -2.6 to 3.9; 3 RCTs), sleep disruption (mean difference = -0.3, 95% CI = -0.8 to 0.2; 3 RCTs), or vomiting (RR = 1.00, 95% CI = 0.51-1.96; 4 RCTs). There was a statistically significant reduction in the median frequency of monthly seizures with cannabidiol compared with placebo (-19.8%, 95% CI = -27.0% to -12.6%; 3 RCTs) and an increase in the number of participants with at least a 50% reduction in seizures (RR = 1.76, 95% CI = 1.07-2.88; 1 RCT) and diarrhea (RR = 2.25, 95% CI = 1.38-3.68; 3 RCTs). Death and status epilepticus were infrequently reported. SIGNIFICANCE: Evidence from high-quality RCTs suggests that cannabidiol probably reduces seizures among children with drug-resistant epilepsy (moderate certainty). At this time, the evidence base is primarily limited to cannabidiol, and these findings should not be extended to all cannabis-based products.

Position Statement on the Use of Medical Cannabis for the Treatment of Epilepsy in Canada.

In Canada, recreational use of cannabis was legalized in October 2018. This policy change along with recent publications evaluating the efficacy of cannabis for the medical treatment of epilepsy and media awareness about its use have increased the public interest about this agent. The Canadian League Against Epilepsy Medical Therapeutics Committee, along with a multidisciplinary group of experts and Canadian Epilepsy Alliance representatives, has developed a position statement about the use of medical cannabis for epilepsy. This article addresses the current Canadian legal framework, recent publications about its efficacy and safety profile, and our understanding of the clinical issues that should be considered when contemplating cannabis use for medical purposes.

Énoncé de position quant à l'utilisation du cannabis médical dans le traitement de l'épilepsie. L'utilisation du cannabis à des fins récréatives a été légalisée au Canada en octobre 2018. Parallèlement à ce changement de politique, de récentes publication visant à évaluer l'efficacité du cannabis dans le traitement de l'épilepsie, de même qu'une sensibilisation médiatique accrue en ce qui concerne son utilisation, ont eu pour effet d'augmenter l'intérêt du grand public à son égard. Le Comité médical thérapeutique de la Ligue canadienne contre l'épilepsie (LCCE), de concert avec un groupe multidisciplinaire d'experts et des représentants de l'Alliance canadienne de l'épilepsie, a ainsi élaboré un énoncé de position en ce qui regarde l'utilisation du cannabis médical dans le traitement de l'épilepsie. Cet article entend donc aborder le cadre légal qui prévaut actuellement au Canada et examiner de récentes publications s'étant penchées sur le profil sécuritaire et sur l'efficacité du cannabis. De plus, nous voulons apporter un éclairage au sujet des aspects cliniques dont il faudrait tenir compte au moment d'envisager l'utilisation du cannabis à des fins médicales.

The role of surgery in refractory epilepsy secondary to polymicrogyria in the pediatric population.

OBJECTIVE: Polymicrogyria (PMG) is a common malformation of cortical development. Many patients with PMG will have medically refractory epilepsy but the role of epilepsy surgery is unclear. The objective of this study was to assess the efficacy of surgical resection/disconnection in achieving seizure control in pediatric patients with PMG. METHODS: A retrospective review of children undergoing epilepsy surgery for PMG between 2002 and 2017 at The Hospital for Sick Children in Toronto, Canada, was performed. RESULTS: A total of 12 children aged 6 months to 17.8 years (median 8.8 years) underwent resective surgery (7 children) or functional hemispherectomy (5 children). Gross total resection or complete disconnection of PMG was carried out in 7 of 12 children. Follow-up duration was between 1 and 9 years (median 2.1 years). Nine children remained seizure-free at last follow-up. Complete resection or disconnection of PMG led to seizure freedom in 6 of 7 patients (86%), whereas subtotal resection produced seizure freedom in 3 of 5 patients (60%). SIGNIFICANCE: We present one of the largest surgical series of pediatric PMG patients. Seizure outcomes were best with complete resection/disconnection of PMG. However, tailored resections based on electroclinical and neuroradiologic data can produce good outcomes and remain an appropriate strategy for patients with extensive PMG.

Clinical, EEG, MRI, MEG, and surgical outcomes of pediatric epilepsy with astrocytic inclusions versus focal cortical dysplasia.

OBJECTIVE: Astrocytic inclusions (AIs) have been identified on histologic specimens of patients with early onset seizures, and the proteomic contents have been described. The aim of this study was to compare the clinical, electroencephalography (EEG), magnetoencephalography (MEG), magnetic resonance imaging (MRI), and surgical outcomes of AIs relative to focal cortical dysplasia (FCD). METHODS: We assessed the clinical manifestations, semiology, ictal and interictal features on video-EEG, MEG, MRI features, and surgical outcomes of children with histologically proven AIs compared to FCD. RESULTS: Six children had AIs and 27 had FCD. Children with AIs had an earlier age at seizure onset, periodic spasms (all children), and interictal epileptiform discharges consisting of a mixture of generalized or diffuse hemispheric slow waves, sharp waves, spikes and polyspikes. Children with FCD were less likely to have spasms (4/27 [15%]), and the morphology of the diffuse hemispheric or generalized discharges were different from those of AI, consisting of spike-and-waves, polyspike-and-waves, sharp-and-slow waves, and paroxysmal fast activity. Patients with AIs were less likely to have tightly clustered MEG spike sources (3/6 [50%] vs. 23/27 [85%]), and more likely to demonstrate abnormal sulcation and gyration pattern (4/6 [67%] vs. 2/27 [7%]) and gray matter heterotopia (2/6 [33%] vs. 0/27 [0%]) than patients with FCD. Four children with AIs had resection and two had biopsy but did not undergo resection. Children with AIs had lower rates of seizure freedom after surgery compared to FCD (1/4 [25%] vs. 15/27 [56%], respectively). SIGNIFICANCE: Although there were some similarities between AIs and FCD, patients with AIs were more likely to present with early onset periodic spasms, have unusual interictal epileptiform discharges, abnormal sulcation, gyration pattern, and gray matter heterotopia, and were less likely to be seizure free following surgical resection relative to FCD. Further study with a larger sample size is needed to validate our findings.

Intravenous ketamine for the treatment of refractory status epilepticus: a retrospective multicenter study.

PURPOSE: To examine patterns of use, efficacy, and safety of intravenous ketamine for the treatment of refractory status epilepticus (RSE). METHODS: Multicenter retrospective review of medical records and electroencephalography (EEG) reports in 10 academic medical centers in North America and Europe, including 58 subjects, representing 60 episodes of RSE that were identified between 1999 and 2012. Seven episodes occurred after anoxic brain injury. KEY FINDINGS: Permanent control of RSE was achieved in 57% (34 of 60) of episodes. Ketamine was felt to have contributed to permanent control ("possible" or "likely" responses) in 32% (19 of 60) including seven (12%) in which ketamine was the last drug added (likely responses). Four of the seven likely responses, but none of the 12 possible ones, occurred in patients with postanoxic brain injury. No likely responses were observed when infusion rates were lower than 0.9 mg/kg/h, when ketamine was introduced at least 8 days after SE onset, or after failure of seven or more drugs. Ketamine was discontinued due to possible adverse events in five patients. Complications were mostly attributed to concurrent drugs, especially other anesthetics. Mortality rate was 43% (26 of 60), but was lower when SE was controlled within 24 h of ketamine initiation (16% vs. 56%, p = 0.0047). SIGNIFICANCE: Ketamine appears to be a relatively effective and safe drug for the treatment of RSE. This retrospective series provides preliminary data on effective dose and appropriate time of intervention to aid in the design of a prospective trial to further define the role of ketamine in the treatment of RSE.

The Epilepsy Surgery Experience in Children With Infantile Epileptic Spasms Syndrome at a Tertiary Care Center in Canada.

Background: Infantile epileptic spasms syndrome is an epileptic encephalopathy, characterized by spasms, hypsarrhythmia, and developmental regression. Appropriately selected patients with infantile epileptic spasms syndrome may be candidates for epilepsy surgery. Methods: This is a single-center retrospective case series of children 0-18 years with a current or previous diagnosis of infantile epileptic spasms syndrome with a lesion on magnetic resonance imaging (MRI) and/or positron emission tomography scan who underwent epilepsy surgery at The Hospital for Sick Children (HSC) in Toronto, Canada. The records of 223 patients seen in the infantile epileptic spasms syndrome clinic were reviewed. Results: Nineteen patients met inclusion criteria. The etiology of infantile epileptic spasms syndrome was encephalomalacia in 6 patients (32%), malformations of cortical development in 12 patients (63%), and atypical hypoglycemic injury in 1 patient (5%). Nine patients (47%) underwent hemispherectomy, and 10 patients (53%) underwent lobectomy/lesionectomy. Three patients (16%) underwent a second epilepsy surgery. Fifteen patients (79%) were considered ILAE seizure outcome class 1 (completely seizure free; no auras) at their most recent follow-up visit. The percentage of patients who were ILAE class 1 at most recent follow-up decreased with increasing duration of epilepsy prior to surgery. Developmental outcome after surgery was improved in 14 of 19 (74%) and stable in 5 of 19 (26%) patients. Conclusions: Our study found excellent seizure freedom rates and improved developmental outcomes following epilepsy surgery in patients with a history of infantile epileptic spasms syndrome with a structural lesion detected on MRI brain. Patients who undergo surgery earlier have improved seizure freedom rates and improved developmental outcomes.

Predictors of nonconvulsive seizures among critically ill children.

PURPOSE: Continuous electroencephalography (EEG) monitoring is a valuable tool for the detection of seizures among critically ill children, in particular when these seizures occur without clinical signs: termed nonconvulsive seizures. Continuous EEG monitoring is a limited resource in many centers. We sought to identify which critically ill children most frequently experience nonconvulsive seizures, and thus may particularly benefit from continuous EEG monitoring. METHODS: Single-center review was undertaken of consecutive diagnostic continuous EEG (cEEG) recordings performed in our pediatric and neonatal intensive care units (ICUs). We examined the indications for monitoring, the clinical characteristics of monitored patients, the occurrence and timing of seizures, and clinical and EEG characteristics associated with nonconvulsive seizures. KEY FINDINGS: One hundred twenty-one patients underwent diagnostic continuous EEG monitoring, for a mean duration of 26 h. Seizures were detected in 32% of these patients, of which 90% experienced some nonconvulsive seizures, and 72% experienced exclusively nonconvulsive seizures. Patients with nonconvulsive seizures had significantly greater odds of having acute epilepsy, acute structural brain injury, prior in-hospital convulsive seizures, and the presence of interictal epileptiform abnormalities on EEG. SIGNIFICANCE: Seizures are common among critically ill children undergoing diagnostic cEEG monitoring. The great majority of these seizures are nonconvulsive, requiring EEG for their detection. Predictors of nonconvulsive seizures include acute epilepsy, acute structural brain injury, prior in-hospital convulsive seizures, and interictal epileptiform abnormalities on EEG. These findings can help inform future allocation of limited cEEG monitoring resources to those patients at greatest risk for nonconvulsive seizures.

Focal resection of fast ripples on extraoperative intracranial EEG improves seizure outcome in pediatric epilepsy.

PURPOSE: High-frequency oscillations (HFOs), termed ripples at 80-200 Hz and fast ripples (FRs) at >200/250 Hz, recorded by intracranial electroencephalography (EEG), may be a valuable surrogate marker for the localization of the epileptogenic zone. We evaluated the relationship of the resection of focal brain regions containing high-rate interictal HFOs and the seizure-onset zone (SOZ) determined by visual EEG analysis with the postsurgical seizure outcome, using extraoperative intracranial EEG monitoring in pediatric patients and automated HFO detection. METHODS: We retrospectively analyzed 28 pediatric epilepsy patients who underwent extraoperative intracranial video-EEG monitoring prior to focal resection. Utilizing the automated analysis, we identified interictal HFOs during 20 min of sleep EEG and determined the brain regions containing high-rate HFOs. We investigated spatial relationships between regions with high-rate HFOs and SOZs. We compared the size of these regions, the surgical resection, and the amount of the regions with high-rate HFOs/SOZs within the resection area with seizure outcome. KEY FINDINGS: Ten patients were completely seizure-free and 18 were not at 2 years after surgery. The brain regions with high-rate ripples were larger than those with high-rate FRs (p = 0.0011) with partial overlap. More complete resection of the regions with high-rate FRs significantly correlated with a better seizure outcome (p = 0.046). More complete resection of the regions with high-rate ripples tended to improve seizure outcome (p = 0.091); however, the resection of SOZ did not influence seizure outcome (p = 0.18). The size of surgical resection was not associated with seizure outcome (p = 0.22-0.39). SIGNIFICANCE: The interictal high-rate FRs are a possible surrogate marker of the epileptogenic zone. Interictal ripples are not as specific a marker of the epileptogenic zone as interictal FRs. Resection of the brain regions with high-rate interictal FRs in addition to the SOZ may achieve a better seizure outcome.

The Phenotypic Spectrum of Tuberous Sclerosis Complex: A Canadian Cohort.

OBJECTIVE: We aimed to further elucidate the phenotypic spectrum of Tuberous Sclerosis Complex (TSC) depending on genotype. METHODS: A retrospective review of patients seen in the TSC clinic at the Hospital for Sick Children was conducted and the frequency of TSC manifestations was compared based on genotype. RESULTS: Nineteen-patients had TSC1 mutations, 36 had TSC2 mutations and 11 had no mutation identified (NMI). Patients with TSC2 mutations had a higher frequency of early-onset epilepsy and more frequent systemic manifestations. The NMI group had milder neurologic and systemic manifestations. Our data did not demonstrate that intellectual disability and infantile spasms were more common in TSC2 mutations. CONCLUSIONS: This is the first Canadian pediatric cohort exploring the genotype-phenotype relationship in TSC. We report that some manifestations are more frequent and severe in TSC2 mutations and that NMI may have a milder phenotype. Disease surveillance and counseling should continue regardless of genotype until this is better elucidated.

Retinal defect in children with infantile spasms of varying etiologies: An observational study.

OBJECTIVE: To determine the prevalence of retinal defect in children with infantile spasms (IS) unrelated to treatment with vigabatrin and clarify if specific primary etiologies for IS are associated with retinal defect more than others. METHODS: This was an observational cohort study including 312 patients (176 male, 136 female) with IS who were vigabatrin-naive. Participants ranged from 1.7 to 34.7 months of age (mean 8.8 months). Electroretinograms (ERGs) were performed according to the International Society for Clinical Electrophysiology of Vision. Retinal defect was identified as abnormal if the 30-Hz flicker ERG amplitude was lower than the age-corrected normal 95% prediction interval. The primary etiology for IS, as determined by the treating pediatric neurologist(s), was obtained from patient health records and classified into 1 of 9 etiologic subgroups: (1) genetic disorders alone, (2) genetic-structural disorders, (3) structural-congenital, (4) structural-acquired (perinatal), (5) structural-acquired (postnatal), (6) metabolic disorders, (7) immunologic disorders, (8) infectious, and (9) unknown causes. RESULTS: Fifty-nine of the 312 vigabatrin-naive children (18.9%) showed retinal defect and the prevalence of retinal defect was highest (24.4%) in the structural-acquired (perinatal) subgroup, which included hypoxic-ischemic defect. Retinal function compared across subgroups showed no significant difference. CONCLUSIONS: Care is required in diagnosing retinal toxicity, which would be enhanced by baseline flicker ERG in children with IS prior to starting vigabatrin.

Economic Evaluation of Cannabinoid Oil for Dravet Syndrome: A Cost-Utility Analysis.

INTRODUCTION: Cannabinoid oils are being increasingly used to treat Dravet syndrome, yet the long-term costs and outcomes of this approach are unknown. Thus, we examined the cost effectiveness of cannabinoid oil as an adjunctive treatment (added to clobazam and valproate), compared with adjunctive stiripentol or with clobazam and valproate alone, for the treatment of Dravet syndrome in children. METHODS: We performed a probabilistic cost-utility analysis from the perspective of the Canadian public health care system, comparing cannabinoid oil and stiripentol (both on a background of clobazam and valproate) with clobazam and valproate alone. Costs and quality-adjusted life-years (QALYs) were estimated using a Markov model that followed a cohort of children aged from 5 to 18 years through model states related to seizure frequency. Model inputs were obtained from the literature. The cost effectiveness of adjunctive cannabinoid oil, adjunctive stiripentol, and clobazam/valproate alone was assessed through sequential analysis. The influence of perspective and other assumptions were explored in scenario analyses. All costs are expressed in 2019 Canadian dollars, and costs and QALYs were discounted at a rate of 1.5% per year. RESULTS: The incremental cost per QALY gained with the use of adjunctive cannabinoid oil, from the health care system perspective, was $32,399 compared with clobazam and valproate. Stiripentol was dominated by cannabinoid oil, producing fewer QALYs at higher costs. At a willingness-to-pay threshold of $50,000, cannabinoid oil was the optimal treatment in 76% of replications. From a societal perspective, cannabinoid oil dominated stiripentol and clobazam/valproate. The interpretation of the results was insensitive to model and input assumptions. CONCLUSION: Compared with clobazam/valproate, adjunctive cannabinoid oil may be a cost-effective treatment for Dravet syndrome, if a decision maker is willing to pay at least $32,399 for each QALY gained. The opportunity costs of continuing to fund stiripentol, but not cannabinoid oil, should be considered.

A Review of Investigations for Patients With Tuberous Sclerosis Complex Who Were Referred to the Tuberous Sclerosis Clinic at The Hospital for Sick Children: Identifying Gaps in Surveillance.

OBJECTIVE: As a newly established tuberous sclerosis clinic (TSC) clinic at The Hospital for Sick Children, we reviewed our referrals to determine if children with TSC received appropriate surveillance as advised by the 2012 International Tuberous Sclerosis Complex Consensus Recommendations. METHODS: We completed a retrospective review of all patients seen in the TSC clinic from January 2016 to December 2017 to determine if children referred to the clinic had appropriate surveillance as suggested by the Tuberous Sclerosis Complex Consensus Recommendations. RESULTS: Ninety patients were seen in the TSC clinic. The median age at first visit was 9.9 years, and 47 were males. Seventy-six percent had undergone genetic testing before the initial clinic visit; however, genetic counseling was completed in only 66%. Brain magnetic resonance imaging was completed in 94%, abdominal imaging was completed in 91%, and an echocardiography and electrocardiography in 88% and 83%, respectively. In addition, dermatology and ophthalmology evaluations were completed in 78% and 91%, respectively. Assessment of TSC-associated neuropsychiatric disorders (TAND) was only completed in 4% of the patients. CONCLUSIONS: Systems surveillance was completed in the majority before the first TSC clinic visit. However, TSC-associated neuropsychiatric disorder screening was completed in few cases. This suggests that referring physicians may not be familiar with the neuropsychiatric manifestations of TSC and that there may be underdiagnosed or undertreated illness. Future emphasis should be placed on educating all practitioners to assess and treat tuberous sclerosis complex-associated neuropsychiatric disorder in tuberous sclerosis complex.

Neurologists' perspectives on medical cannabis for pediatric drug-resistant epilepsy in Canada: A qualitative interview study.

PURPOSE: To understand the experiences with and perspectives of neurologists about the use of medical cannabis in the treatment of pediatric drug-resistant epilepsy. METHODS: In this qualitative study, we interviewed neurologists who provide care to children with drug-resistant epilepsy in Canada. Through semi-structured telephone interviews, we sought participants' views about and experiences with medical cannabis for the treatment of drug-resistant epilepsy in children. Here we present a thematic summary of the interviews. RESULTS: The 12 interviewed neurologists generally perceived medical cannabis as a viable treatment option for children with drug-resistant epilepsy; however, participants identified important gaps in the evidence and implications for their practices. Six themes were generated from the content of the interviews: learning about medical cannabis; perceptions about medical cannabis; discussing medical cannabis with parents; experiences with medical cannabis authorization; barriers to authorizing medical cannabis; and the impact of medical cannabis on clinical care. Of note, while some neurologists took on all aspects of the children's care, including medical cannabis, others referred interested families to non-neurology health care professionals. CONCLUSION: Our findings highlight the diverse opinions and experiences of neurologists in Canada with medical cannabis for the treatment of drug-resistant epilepsy in children, including with the authorization process and caring for children using medical cannabis. Additional education about medical cannabis may be warranted, in order to better prepare neurologists to have informed and open conversations with parents about this treatment option and to provide care for children using medical cannabis.

Cannabis-based products for pediatric epilepsy: An updated systematic review.

PURPOSE: To provide an up-to-date summary of the benefits and harms of cannabis-based products for epilepsy in children. METHODS: We updated our earlier systematic review, by searching for studies published up to May 2019. We included randomized controlled trials (RCTs) and non-randomized studies (NRS) involving cannabis-based products administered to children with epilepsy. Outcomes were seizure freedom, seizure frequency, quality of life, sleep, status epilepticus, death, gastrointestinal adverse events, and emergency room visits. RESULTS: Thirty-five studies, including four RCTs, have assessed the benefits and harms of cannabis-based products in pediatric epilepsy (12 since April 2018). All involved cannabis-based products as adjunctive treatment, and most involved cannabidiol. In the RCTs, there was no statistically significant difference between cannabidiol and placebo for seizure freedom (relative risk 6.77, 95 % confidence interval [CI] 0.36-128.38), quality of life (mean difference [MD] 0.6, 95 %CI -2.6 to 3.9), or sleep disruption (MD -0.3, 95 %CI -0.8 to 0.2). Data from both RCTs and NRS suggest that cannabidiol reduces seizure frequency and increases treatment response; however, there is an increased risk of gastrointestinal adverse events. CONCLUSION: Newly available evidence supports earlier findings that cannabidiol probably reduces the frequency of seizures among children with drug-resistant epilepsy. PROSPERO: CRD42018084755.

Cost-effectiveness of cannabinoids for pediatric drug-resistant epilepsy: protocol for a systematic review of economic evaluations.

BACKGROUND: Drug-resistant epilepsy negatively impacts the quality of life and is associated with increased morbidity and mortality and high costs to the healthcare system. Cannabis-based treatments may be effective in reducing seizures in this population, but whether they are cost-effective is unclear. In this systematic review, we will search for cost-effectiveness analyses involving the treatment of pediatric drug-resistant epilepsy with cannabis-based products to inform decision-making by public healthcare payers about reimbursement of such products. We will also search for cost-effectiveness analyses of other pharmacologic treatments for pediatric drug-resistant epilepsy, as well as estimates of healthcare resource use, costs, and utilities, for use in a subsequent cost-utility analysis to address this decision problem. METHODS: We will search the published and gray literature for economic evaluations of cannabis-based products and other pharmacologic treatments for pediatric drug-resistant epilepsy, as well as resource utilization and utility studies. Two independent reviewers will screen the title and abstract of each identified record and the full-text version of any study deemed potentially relevant. Study and population characteristics, the incremental cost-effectiveness ratio (ICER), as well as total costs and benefits, will be extracted, and quality will be assessed by use of the Drummond and CHEERS checklists; context-specific issues will also be considered. From model-based cost-utility and cost-effectiveness analyses, we will extract and summarize the model structure, including health states, time horizon, and cycle length. From resource utilization studies, we will extract data about the frequency of resource use (e.g., neurology visits, emergency department visits, admissions to hospital). From utility studies, we will extract the utility for each health state, the source of the preferences (e.g., child, parent, patient, general public), and the method of elicitation. DISCUSSION: Drug-resistant epilepsy in children is associated with important costs to the healthcare system, and decision-makers require high-quality evidence on which to base reimbursement decisions. The results of this review will be useful to both decision-makers considering the decision problem of whether to reimburse cannabis-based products through public formularies and to analysts conducting studies in this area. SYSTEMATIC REVIEW REGISTRATION: PROSPERO no.: CRD42018099591 .

Decision Models for Assessing the Cost Effectiveness of Treatments for Pediatric Drug-Resistant Epilepsy: A Systematic Review of Economic Evaluations.

BACKGROUND: Drug-resistant epilepsy affects about one-third of children with epilepsy and is associated with high costs to the healthcare system, yet the cost effectiveness of most treatments is unclear. Use of cannabis-based products for epilepsy is increasing, and the cost effectiveness of such strategies relative to conventional pharmacologic treatments must be considered. OBJECTIVE: The objective of this systematic review was to identify economic evaluations of cannabis-based treatments for pediatric drug-resistant epilepsy. We also sought to identify and appraise decision models that have been used in economic evaluations of pharmacologic treatments (i.e., antiepileptic drugs) in this population. METHODS: Electronic searches of MEDLINE, EMBASE, and the Cochrane library, as well as a targeted grey literature search, were undertaken (11 June 2018). Model-based full economic evaluations involving cannabis-based treatments or pharmacologic treatments for drug-resistant epilepsy in children were eligible for inclusion. Two independent reviewers selected studies for inclusion, and study quality was assessed by use of the Drummond and Consolidated Health Economic Evaluation Reporting Standards (CHEERS) checklists. Study findings, as well as model characteristics, are narratively summarized. RESULTS: Nine economic evaluations involving children with drug-resistant epilepsy were identified; however, none involved cannabis-based treatments. All studies involved pharmacologic treatments compared with other pharmacologic treatments or non-pharmacologic treatments (i.e., ketogenic diet, epilepsy surgery, vagus nerve stimulation). Few studies have assessed the cost effectiveness of pharmacologic treatments in specific drug-resistant epilepsy syndromes, including Dravet and Lennox-Gastaut syndromes. Five included studies involved use of Markov models with a similar structure (i.e., health states based on seizure frequency relative to baseline). There was a wide range of methodological quality, and few studies fully addressed context-specific issues such as weight gain and treatment switching. CONCLUSION: Whether cannabis-based treatments for pediatric drug-resistant epilepsy represent good value for money has yet to be investigated. Economic evaluations of such treatments are needed and should address issues of particular importance in pediatric epilepsy, including weight gain over time, switching or discontinuation of treatments, effectiveness of interventions and comparators, and long-term effectiveness beyond the duration of available clinical studies. PROSPERO REGISTRATION: CRD42018099591.

Economic Evaluation of Stiripentol for Dravet Syndrome: A Cost-Utility Analysis.

BACKGROUND: Dravet syndrome is a catastrophic form of pediatric treatment-resistant epilepsy with few effective treatment options. Stiripentol is approved for use in Canada for treatment of Dravet syndrome, but the associated long-term costs and benefits have not been well-studied and its cost effectiveness is unclear. OBJECTIVE: The aim of this study was to evaluate the cost effectiveness of stiripentol as an adjunctive treatment to clobazam and valproate for treatment of Dravet syndrome from the perspective of the Canadian public healthcare payer. METHODS: A cost-utility analysis was performed to estimate the costs and quality-adjusted life-years (QALYs) associated with adjunctive stiripentol treatment compared with clobazam and valproate alone in children with Dravet syndrome. Transition probabilities, drug efficacy, utility weights, and costs were obtained from a review of the literature. Probabilistic analyses were conducted using a Markov model with health states related to seizure frequency. A 10-year horizon was used. The incremental cost per QALY gained (incremental cost-effectiveness ratio [ICER]) for adjunctive use of stiripentol was calculated, and assumptions were explored in scenario analyses. All costs are expressed in 2017 Canadian dollars ($Can). RESULTS: Compared with clobazam and valproate alone, the adjunctive use of stiripentol is associated with an ICER of $Can151,310. At a willingness-to-pay threshold of $Can50,000, the probability that stiripentol was the optimal treatment was 5.2%. The cost of stiripentol would need to be reduced by 61.4% for stiripentol to be cost effective. CONCLUSION: From the perspective of the Canadian public healthcare payer, stiripentol is not cost effective at its current price at a willingness-to-pay threshold of $Can50,000. Funding stiripentol will be associated with important opportunity costs that bear consideration.

A prospective open-label trial of a CBD/THC cannabis oil in dravet syndrome.

INTRODUCTION: Both Δ9 Tetrahydrocannabidiol (THC) and cannabidiol (CBD) components of cannabis, have been shown to have anticonvulsant effects. Cannabis oils are used to treat seizures in drug-resistant epilepsy (DRE). Recent trials provide data on dosing, side effects, and efficacy of CBD, yet there is a paucity of information on THC in epilepsy. Primary objective was to establish dosing and tolerability of TIL-TC150 - a cannabis plant extract produced by Tilray®, containing 100 mg/mL CBD and 2 mg/mL THC- in children with Dravet syndrome. Secondary objectives were to assess impact of therapy on seizures, electroencephalogram (EEG) and quality of life. METHODS: Twenty children received add-on therapy with TIL-TC150. The dose ranged from 2 to 16 mg/kg/day of CBD and 0.04 to 0.32 mg/kg/day of THC. Patients were monitored for tolerability and adverse events, and secondary objectives. RESULTS: Nineteen participants completed the 20-week intervention. Mean dose achieved was 13.3 mg/kg/day of CBD (range 7-16 mg/kg/day) and 0.27 mg/kg/day of THC (range 0.14-0.32 mg/kg/day). Adverse events, common during titration included somnolence, anorexia, and diarrhea. Abnormalities of liver transaminases and platelets were observed with concomitant valproic acid therapy. There was a statistically significant improvement in quality of life, reduction in EEG spike activity, and median motor seizure reduction of 70.6%, with 50% responder rate of 63%. CONCLUSIONS: TIL-TC150 was safe and well tolerated in our subjects. TIL-TC150 treatment resulted in a reduction in seizure counts, spike index on EEG, and improved quality of life measures. This study provides safety and dosing information for THC-containing cannabinoid preparations.