Safety and pharmacokinetic profile of rufinamide in pediatric patients aged less than 4 years with Lennox-Gastaut syndrome: An interim analysis from a multicenter, randomized, active-controlled, open-label study

Pharmacokinetic Variability of Rufinamide and Stiripentol in Children With Refractory Epilepsy: A Retrospective Study of Therapeutic Drug Monitoring From the National Epilepsy Centers in Denmark and Norway

BACKGROUND

Rufinamide and stiripentol, orphan drugs used in Lennox-Gastaut and Dravet syndromes, respectively, are antiseizure medications (ASMs), often administered to children; however, pharmacokinetic studies are lacking. The authors compared the pharmacokinetic variability of these drugs with respect to the dose, serum concentrations, comedication, age, and duration of treatment.

METHODS

Children and adolescents (<18 years) whose serum concentrations were measured were retrospectively identified from the therapeutic drug monitoring (TDM) databases at 2 national epilepsy centers in Norway and Denmark (2012-2021).

RESULTS

Data from 165 patients (56% boys/44% girls) treated with rufinamide and 52 patients (50% boys/50% girls) treated with stiripentol were included. For rufinamide, the median age was 10 (range 2-17) years, dose 23 (3-73) mg/d, and serum concentration 34 (3-227) µmol/L [8.1 mg/L (0.71-54.0 mg/L)]. For stiripentol, the median age was 8.5 (range 1-17) years, dose 37 (18-76) mg/d, and serum concentration 33 (4-113) µmol/L [7.7 mg/L (0.93-26.3 mg/L)]. The concomitant use of 1-9 other ASMs during the data collection was noted. Pharmacokinetic variability, calculated as the concentration/(dose/kg) ratio, ranged from 0.26 to 11.31 (µmol/L)/(mg/kg) for rufinamide and 0.17-1.52 (µmol/L)/(mg/kg) for stiripentol. The intraindividual coefficients of variation ranged widely, from 5% to 110% for rufinamide and 11%-117% for stiripentol. The treatment period was at least 5 years in 50% of patients. No statistically significant effects of age, sex, or ASM comedication were observed, possibly due to the small sample size and heterogeneous groups with variable seizure situations, comorbidities, and changes in comedication and physiology.

CONCLUSIONS

This study demonstrates considerable pharmacokinetic variability in and between patients for both drugs and similar use in terms of age, burden of comedication and retention rates. TDM may be useful in the clinical setting to monitor and optimize treatment in this vulnerable patient group.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Psychobehavioural and Cognitive Adverse Events of Anti-Seizure Medications for the Treatment of Developmental and Epileptic Encephalopathies

The developmental and epileptic encephalopathies encompass a group of rare syndromes characterised by severe drug-resistant epilepsy with onset in childhood and significant neurodevelopmental comorbidities. The latter include intellectual disability, developmental delay, behavioural problems including attention-deficit hyperactivity disorder and autism spectrum disorder, psychiatric problems including anxiety and depression, speech impairment and sleep problems. Classical examples of developmental and epileptic encephalopathies include Dravet syndrome, Lennox-Gastaut syndrome and tuberous sclerosis complex. The mainstay of treatment is with multiple anti-seizure medications (ASMs); however, the ASMs themselves can be associated with psychobehavioural adverse events, and effects (negative or positive) on cognition and sleep. We have performed a targeted literature review of ASMs commonly used in the treatment of developmental and epileptic encephalopathies to discuss the latest evidence on their effects on behaviour, mood, cognition, sedation and sleep. The ASMs include valproate (VPA), clobazam, topiramate (TPM), cannabidiol (CBD), fenfluramine (FFA), levetiracetam (LEV), brivaracetam (BRV), zonisamide (ZNS), perampanel (PER), ethosuximide, stiripentol, lamotrigine (LTG), rufinamide, vigabatrin, lacosamide (LCM) and everolimus. Bromide, felbamate and other sodium channel ASMs are discussed briefly. Overall, the current evidence suggest that LEV, PER and to a lesser extent BRV are associated with psychobehavioural adverse events including aggressiveness and irritability; TPM and to a lesser extent ZNS are associated with language impairment and cognitive dulling/memory problems. Patients with a history of behavioural and psychiatric comorbidities may be more at risk of developing psychobehavioural adverse events. Topiramate and ZNS may be associated with negative effects in some aspects of cognition; CBD, FFA, LEV, BRV and LTG may have some positive effects, while the remaining ASMs do not appear to have a detrimental effect. All the ASMs are associated with sedation to a certain extent, which is pronounced during uptitration. Cannabidiol, PER and pregabalin may be associated with improvements in sleep, LTG is associated with insomnia, while VPA, TPM, LEV, ZNS and LCM do not appear to have detrimental effects. There was variability in the extent of evidence for each ASM: for many first-generation and some second-generation ASMs, there is scant documented evidence; however, their extensive use suggests favourable tolerability and safety (e.g. VPA); second-generation and some third-generation ASMs tend to have the most robust evidence documented over several years of use (TPM, LEV, PER, ZNS, BRV), while evidence is still being generated for newer ASMs such as CBD and FFA. Finally, we discuss how a variety of factors can affect mood, behaviour and cognition, and untangling the associations between the effects of the underlying syndrome and those of the ASMs can be challenging. In particular, there is enormous heterogeneity in cognitive, behavioural and developmental impairments that is complex and can change naturally over time; there is a lack of standardised instruments for evaluating these outcomes in developmental and epileptic encephalopathies, with a reliance on subjective evaluations by proxy (caregivers); and treatment regimes are complex involving multiple ASMs as well as other drugs.

Sex differences in side effects of antiseizure medications in pediatric patients with epilepsy: A systematic review

PURPOSE

To perform a systematic review searching for differences in the side effects of antiseizure medications (ASMs) with respect to sex in pediatric patients with epilepsy.

METHODS

We carried out a comprehensive literature search of the PubMed database and all results up to April 2020 were included. Titles, abstracts, and full texts of the articles were screened by two independent reviewers. We included all studies evaluating the side effects of ASMs in patients with epilepsy younger than 18 years, with reference to the two sexes. Studies on ASMs used for indications other than epilepsy were excluded.

RESULTS

A total of 5164 studies were identified. Sixty-seven studies were finally included, 5 of them also including adult patients in the sample. Sixteen studies revealed sex-related differences in side effects of ASMs, disclosing a higher frequency of general side effects in girls: a higher risk of overweight, hyperammonaemia, high leptin levels, and carnitine deficiency in girls on valproic acid; a lower height increase, an increased risk of weight loss, the anecdotical occurrence of acute psychosis in girls on topiramate; a higher risk of retinal toxicity in boys on vigabatrin.

CONCLUSION

The effect of sex on susceptibility to side effects of ASMs is poorly investigated with sparse results, and it could be underestimated. The findings of our study point to the presence of sex differences which should be thoroughly investigated to be confirmed, highlighting the need for a systematic evaluation of sex as a determinant variable influencing the response to medications in clinical research.

Therapeutic Drug Monitoring for Rufinamide in Japanese Patients With Epilepsy: Focus on Drug Interactions, Tolerability, and Clinical Effectiveness

BACKGROUND

The purposes of this study were to assess drug interactions between rufinamide and concomitant antiepileptic drugs (AEDs) and to identify the therapeutic window for rufinamide.

METHODS

Serum samples (n = 1531) were obtained from 178 patients (aged 2-57 years), and clinical records were retrospectively reviewed to evaluate the safety and efficacy of rufinamide (mean observation time, 1073 ± 846 days).

RESULTS

Rufinamide exhibited linear pharmacokinetics at doses of up to 60 mg/kg (range, 50-3200 mg/d). Concomitant use of the enzyme-inducing AEDs such as phenytoin, carbamazepine, and phenobarbital reduced rufinamide concentrations by 43.4%, 13.2%, and 30.3%, respectively. By contrast, concomitant use of valproate significantly elevated rufinamide concentrations. Clinical response was seen in 41 patients (23.0%), with a median therapeutic concentration (interquartile range) of 20.6 mcg/mL (13.3-27.0). There was no difference in the therapeutic concentrations between seizure types, but patients with tonic/atonic seizures tended to have higher rufinamide concentrations. During the study period, adverse events were reported in 64 patients (35.8%), including somnolence, gastrointestinal disorders, dizziness, and irritability/behavior disorders. Conditional logistic regression analysis showed that patients administered a concentration greater than 20 mcg/mL had an 8.6-fold higher incidence of adverse events.

CONCLUSIONS

Therapeutic drug monitoring for rufinamide is clinically useful for predicting drug interactions between rufinamide and concomitant AEDs. When a patient has tonic/atonic seizures, careful titration is required for concentrations greater than 20 mcg/mL.

Impact of Antiseizure Medications on Appetite and Weight in Children

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

Efficacy and safety of rufinamide as adjunctive therapy in patients with Lennox Gastaut syndrome: A systematic review and Meta-analysis

INTRODUCTION

Rufinamide is an antiseizure medication that acts through sodium channels and is found to be efficacious in patients with Lennox Gastaut syndrome (LGS). However, no systematic review has been conducted in LGS patients to provide an estimate of the efficacy and safety of rufinamide.

METHODS

Different electronic databases were searched for articles describing the use of rufinamide in patients with LGS. For determining primary efficacy outcomes as compared to placebo, we included only studies comparing the efficacy of rufinamide with placebo in LGS patients. We performed an additional analysis to include other uncontrolled studies with a minimum sample size of 20 to provide a more comprehensive estimate of efficacy.

RESULTS

A total of ten studies included 557 patients. Out of them, five studies were placebo-controlled, enrolling a total of 265 patients in the rufinamide group and 203 patients in the placebo group. The average percentage reduction in total seizure frequency per 28 days during the double-blind phase was 29.3% in the rufinamide group compared with 8.3% in the placebo group (difference between the two groups was 20.9%, 95%CI-14.4%-27.3%, p <0.00001). Even for individual seizure types like tonic-clonic seizures, atypical absence seizures, atonic seizures, focal seizures, and myoclonic seizures, rufinamide was more efficacious than placebo(p<0.00001). The number of patients with at least one treatment-emergent adverse effects was significantly higher in rufinamide treated patients (60.2%vs50.7%, p=0.02, RR-1.24(1.03,1.51).

CONCLUSION

Rufinamide is efficacious as adjunctive therapy in patients with LGS in terms of reduction in total seizure frequency and has mild adverse reaction.

Anti-seizure medications for Lennox-Gastaut syndrome

BACKGROUND

Lennox-Gastaut syndrome (LGS) is an age-specific epilepsy syndrome characterised by multiple seizure types, including drop seizures. LGS has a characteristic electroencephalogram, an onset before age eight years and an association with drug resistance. This is an updated version of the Cochrane Review published in 2013.

OBJECTIVES

To assess the efficacy and tolerability of anti-seizure medications (ASMs) for LGS.

SEARCH METHODS

We searched the Cochrane Register of Studies (CRS Web) and MEDLINE (Ovid, 1946 to 28 February 2020) on 2 March 2020. CRS Web includes randomised controlled trials (RCTs) or quasi-RCTs from the Cochrane Central Register of Controlled Trials (CENTRAL); the Specialised Registers of Cochrane Review Groups, including Cochrane Epilepsy; PubMed; Embase; ClinicalTrials.gov; and the World Health Organization's International Clinical Trials Registry Platform (ICTRP). We imposed no language restrictions. We contacted pharmaceutical companies and colleagues in the field to seek any unpublished or ongoing studies.

SELECTION CRITERIA

We considered RCTs, including cross-over trials, of ASMs for LGS in children and adults. We included studies of ASMs used as either monotherapy or as an add-on (adjunctive) therapy. We excluded studies comparing different doses of the same ASM.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodological procedures, including independent, dual assessment for risk of bias and application of the GRADE approach to rate the evidence certainty for outcomes.

MAIN RESULTS

We found no trials of ASM monotherapy. The review included 11 trials (1277 participants; approximately 11 weeks to 112 weeks follow-up after randomisation) using add-on ASMs for LGS in children, adolescents and adults. Two studies compared add-on cannabidiol (two doses) with add-on placebo in children and adolescents only. Neither study reported overall seizure cessation or reduction. We found high-certainty evidence that 72 more people per 1000 (confidence interval (CI) 4 more to 351 more) had adverse events (AE) leading to study discontinuation with add-on cannabidiol, compared to add-on placebo (two studies; 396 participants; risk ratio (RR) 4.90, 95% CI 1.21 to 19.87). One study compared add-on cinromide with add-on placebo in children and adolescents only. We found very low-certainty evidence that 35 more people per 1000 (CI 123 fewer to 434 more) had 50% or greater average reduction of overall seizures with add-on cinromide compared to add-on placebo (one study; 56 participants; RR 1.15, 95% CI 0.47 to 2.86). This study did not report participants with AE leading to study discontinuation. One study compared add-on clobazam (three doses) with add-on placebo. This study did not report overall seizure cessation or reduction. We found high-certainty evidence that 106 more people per 1000 (CI 0 more to 538 more) had AE leading to study discontinuation with add-on clobazam compared to add-on placebo (one study; 238 participants; RR 4.12, 95% CI 1.01 to 16.87). One study compared add-on felbamate with add-on placebo. No cases of seizure cessation occurred in either regimen during the treatment phase (one study; 73 participants; low-certainty evidence). There was low-certainty evidence that 53 more people per 1000 (CI 19 fewer to 716 more) with add-on felbamate were seizure-free during an EEG recording at the end of the treatment phase, compared to add-on placebo (RR 2.92, 95% CI 0.32 to 26.77). The study did not report overall seizure reduction. We found low-certainty evidence that one fewer person per 1000 (CI 26 fewer to 388 more) with add-on felbamate had AE leading to study discontinuation compared to add-on placebo (one study, 73 participants; RR 0.97, 95% CI 0.06 to 14.97). Two studies compared add-on lamotrigine with add-on placebo. Neither study reported overall seizure cessation. We found high-certainty evidence that 176 more people per 1000 (CI 30 more to 434 more) had ≥ 50% average seizure reduction with add-on lamotrigine compared to add-on placebo (one study; 167 participants; RR 2.12, 95% CI 1.19 to 3.76). We found low-certainty evidence that 40 fewer people per 1000 (CI 68 fewer to 64 more) had AE leading to study-discontinuation with add-on lamotrigine compared to add-on placebo (one study; 169 participants; RR 0.49, 95% CI 0.13 to 1.82). Two studies compared add-on rufinamide with add-on placebo. Neither study reported seizure cessation. We found high-certainty evidence that 202 more people per 1000 (CI 34 to 567 more) had ≥ 50% average seizure reduction (one study; 138 participants; RR 2.84, 95% CI 1.31 to 6.18). We found low-certainty evidence that 105 more people per 1000 (CI 17 fewer to 967 more) had AE leading to study discontinuation with add-on rufinamide compared to add-on placebo (one study; 59 participants; RR 4.14, 95% CI 0.49 to 34.86). One study compared add-on rufinamide with another add-on ASM. This study did not report overall seizure cessation or reduction. We found low-certainty evidence that three fewer people per 1000 (CI 75 fewer to 715 more) had AE leading to study discontinuation with add-on rufinamide compared to another add-on ASM (one study; 37 participants; RR 0.96, 95% CI 0.10 to 9.57). One study compared add-on topiramate with add-on placebo. This study did not report overall seizure cessation. We found low-certainty evidence for ≥ 75% average seizure reduction with add-on topiramate (one study; 98 participants; Peto odds ratio (Peto OR) 8.22, 99% CI 0.60 to 112.62) and little or no difference to AE leading to study discontinuation compared to add-on placebo; no participants experienced AE leading to study discontinuation (one study; 98 participants; low-certainty evidence).

AUTHORS' CONCLUSIONS

RCTs of monotherapy and head-to-head comparison of add-on ASMs are currently lacking. However, we found high-certainty evidence for overall seizure reduction with add-on lamotrigine and rufinamide, with low-certainty evidence for AE leading to study discontinuation compared with add-on placebo or another add-on ASM. The evidence for other add-on ASMs for overall seizure cessation or reduction was low to very low with high- to low-certainty evidence for AE leading to study discontinuation. Future research should consider outcome reporting of overall seizure reduction (applying automated seizure detection devices), impact on development, cognition and behaviour; future research should also investigate age-specific efficacy of ASMs and target underlying aetiologies.

Efficacy and Tolerability of Rufinamide in Epileptic Children Younger Than 4 Years

BACKGROUND

Rufinamide, a triazole derivative, is a new-generation antiseizure medication with a novel mechanism of action. We evaluated the efficacy and safety of rufinamide treatment in children with epilepsy younger than 4 years at our center.

METHODS

In this retrospective study, we included children younger than 4 years who had pharmacologically resistant epilepsy and were treated with rufinamide at Boston Children's Hospital between June 2010 and June 2018. Safety and efficacy of rufinamide treatment were assessed immediately prior to initiation of rufinamide and at the last follow-up visit. Responders were defined as patients who had greater than 50% reduction in seizure frequency on follow-up as compared to baseline.

RESULTS

We reviewed records of 128 children and included 103 with complete information. Patients consisted of 60 boys (58%), with a median age of 20 months (interquartile range 13-28, range 2-36). Median treatment duration was 15 months, and median rufinamide dosage at the last follow-up was 42 mg/kg/d (interquartile range 34-56). At the last follow-up, seizure frequency decreased (450 vs 90, P<.001) and overall seizure reduction was 54%. Fifty-one patients (49.5%) were responders with 94% seizure reduction, including 20 (19.4%) who achieved seizure freedom. Treatment retention rate at 12 months was 63%. Thirty patients (29%) developed adverse events and 41 patients (39.8%) discontinued rufinamide because of adverse events (15; 14.5%) and lack of efficacy (26; 25%).

CONCLUSION

Rufinamide is effective in reducing seizure frequency in pediatric epilepsy patients younger than 4 years, and overall well tolerated.

Medical Management in Focal versus Generalized Epilepsy

About 70% of children with new-onset epilepsy have the potential to become seizure-free on antiepileptic drug (AED) monotherapy with appropriately selected first-line medication. In ideal world, physician is expected to achieve best possible seizure control without impacting the quality of life. There is rapid increase in number of AEDs available over last couple of decades. Although not necessarily all of them are superior to old generation drugs in terms of seizure control, certainly there is change in landscape from perspective of tolerability and side-effect profile. Physicians must therefore be familiar with safety, tolerability, therapeutic effects, synergistic combinations as well as AEDs to avoid in specific circumstances. The article attempts to give general overview of available AEDs under broad umbrella of effectiveness against focal and generalized seizures as well as drugs with “broad spectrum.” The emergence of newer AEDs with broad spectrum and favorable side-effect profile is welcome. However, the future lies in better understanding of underlying diverse pathophysiology of clinical symptom “epilepsy” and developing new compounds acting on molecular targets as well as individualizing therapy. Technological advances in molecular genetics research are bringing precision medicine to the fore.

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

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

Rufinamide add-on therapy for drug-resistant epilepsy

BACKGROUND

Epilepsy is a central nervous system disorder (neurological disorder). Epileptic seizures are the result of excessive and abnormal cortical nerve cell electrical activity in the brain. Despite the development of more than 10 new antiepileptic drugs (AEDs) since the early 2000s, approximately a third of people with epilepsy remain resistant to pharmacotherapy, often requiring treatment with a combination of AEDs. In this review, we summarised the current evidence regarding rufinamide, a novel anticonvulsant medication, which, as a triazole derivative, is structurally unrelated to any other currently used anticonvulsant medication when used as an add-on treatment for drug-resistant epilepsy. In January 2009, rufinamide was approved by the US Food and Drug Administration for the treatment of children four years of age and older with Lennox-Gastaut syndrome. It is also approved as an add-on treatment for adults and adolescents with focal seizures. This is an updated version of the original Cochrane Review published in 2018.

OBJECTIVES

To evaluate the efficacy and tolerability of rufinamide when used as an add-on treatment for people with drug-resistant epilepsy.

SEARCH METHODS

We imposed no language restrictions. We contacted the manufacturers of rufinamide and authors in the field to identify any relevant unpublished studies.

SELECTION CRITERIA

Randomised, double-blind, placebo-controlled, add-on trials of rufinamide, recruiting people (of any age or gender) with drug-resistant epilepsy.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion and extracted the relevant data. We assessed the following outcomes: 50% or greater reduction in seizure frequency (primary outcome); seizure freedom; treatment withdrawal; and adverse effects (secondary outcomes). Primary analyses were intention-to-treat (ITT) and we presented summary risk ratios (RRs) with 95% confidence intervals (CIs). We evaluated dose response in regression models. We carried out a risk of bias assessment for each included study using the Cochrane 'Risk of bias' tool and assessed the overall certainty of evidence using the GRADE approach.

MAIN RESULTS

The review included six trials, representing 1759 participants. Four trials (1563 participants) included people with uncontrolled focal seizures. Two trials (196 participants) included individuals with established Lennox-Gastaut syndrome. Overall, the age of adults ranged from 18 to 80 years and the age of children ranged from 4 to 16 years. Baseline phases ranged from 28 to 56 days and double-blind phases from 84 to 96 days. Five of the six included trials described adequate methods of concealment of randomisation, and only three described adequate blinding. All analyses were by ITT. Overall, five studies were at low risk of bias and one had unclear risk of bias due to lack of reported information around study design. All trials were sponsored by the manufacturer of rufinamide and therefore were at high risk of funding bias. The overall RR for 50% or greater reduction in seizure frequency was 1.79 (95% CI 1.44 to 2.22; 6 randomised controlled trials (RCTs), 1759 participants; moderate-certainty evidence), indicating that rufinamide (plus conventional AED) was significantly more effective than placebo (plus conventional AED) in reducing seizure frequency by at least 50% when added to conventionally used AEDs in people with drug-resistant focal epilepsy. Data from only one study (73 participants) reported seizure freedom: RR 1.32 (95% CI 0.36 to 4.86; 1 RCT, 73 participants; moderate-certainty evidence). The overall RR for treatment withdrawal (for any reason and due to AED) was 1.83 (95% CI 1.45 to 2.31; 6 RCTs, 1759 participants; moderate-certainty evidence), showing that rufinamide was significantly more likely to be withdrawn than placebo. Most adverse effects were significantly more likely to occur in the rufinamide-treated group. Adverse events significantly associated with rufinamide were headache, dizziness, somnolence, vomiting, nausea, fatigue, and diplopia. The RRs for these adverse effects were as follows: headache 1.36 (95% Cl 1.08 to 1.69; 3 RCTs, 1228 participants; high-certainty evidence); dizziness 2.52 (95% Cl 1.90 to 3.34; 3 RCTs, 1295 participants; moderate-certainty evidence); somnolence 1.94 (95% Cl 1.44 to 2.61; 6 RCTs, 1759 participants; moderate-certainty evidence); vomiting 2.95 (95% Cl 1.80 to 4.82; 4 RCTs, 777 participants; low-certainty evidence); nausea 1.87 (95% Cl 1.33 to 2.64; 3 RCTs, 1295 participants; moderate-certainty evidence); fatigue 1.46 (95% Cl 1.08 to 1.97; 3 RCTs, 1295 participants; moderate-certainty evidence); and diplopia 4.60 (95% Cl 2.53 to 8.38; 3 RCTs, 1295 participants; low-certainty evidence). There was no important heterogeneity between studies for any outcomes. Overall, we assessed the evidence as moderate to low certainty due to wide CIs and potential risk of bias from some studies contributing to the analysis.

AUTHORS' CONCLUSIONS

For people with drug-resistant focal epilepsy, rufinamide when used as an add-on treatment was effective in reducing seizure frequency. However, the trials reviewed were of relatively short duration and provided no evidence for long-term use of rufinamide. In the short term, rufinamide as an add-on was associated with several adverse events. This review focused on the use of rufinamide in drug-resistant focal epilepsy, and the results cannot be generalised to add-on treatment for generalised epilepsies. Likewise, no inference can be made about the effects of rufinamide when used as monotherapy.

Relationship between saliva and plasma rufinamide concentrations in patients with epilepsy

The assay of saliva samples provides a valuable alternative to the use of blood samples for therapeutic drug monitoring (TDM), at least for certain categories of patients. To determine the feasibility of using saliva sampling for the TDM of rufinamide, we compared rufinamide concentrations in paired samples of saliva and plasma collected from 26 patients with epilepsy at steady state. Within-patient relationships between plasma rufinamide concentrations and dose, and the influence of comedication were also investigated. Assay results in the two tested fluids showed a good correlation (r²  = .78, P < .0001), but concentrations in saliva were moderately lower than those in plasma (mean saliva to plasma ratio = 0.7 ± 0.2). In eight patients evaluated at three different dose levels, plasma rufinamide concentrations increased linearly with increasing dose. Patients receiving valproic acid comedication had higher dose-normalized plasma rufinamide levels than patients comedicated with drugs devoid of strong enzyme-inducing or enzyme-inhibiting activity. Overall, these findings indicate that use of saliva represents a feasible option for the application of TDM in patients treated with rufinamide. Because rufinamide concentrations are lower in saliva than in plasma, a correction factor is needed if measurements made in saliva are used as a surrogate for plasma concentrations.

Adjunctive Rufinamide in Children with Lennox-Gastaut Syndrome: A Literature Review

Lennox-Gastaut syndrome (LGS) is a severe, childhood-onset, developmental epileptic encephalopathy, with different etiologies and co-morbidities. Seizure treatment in LGS represents a major challenge; new antiepileptic drugs (AEDs) are developed to especially address seizures resulting in high morbidity and mortality, such as drop seizures. Rufinamide (RFN) is one of the latest AEDs licensed for patients with LGS. Its mechanism of action involves sodium channels in a way that is unrelated to other AEDs. Here we discuss the use of adjunctive RFN in children and adolescents with LGS and its efficacy and safety profile, based on a systematic literature review. RFN shows a very favorable profile in terms of adverse events and drug-interactions in children. It is particularly effective on tonic-atonic seizures and spasms, impacting on the quality of life of the patients. Further studies are needed to clarify the interaction profile with the newest AEDs for LGS and to assess correlations between the etiology of LGS and drug response to individualize treatment and maximize efficacy.

Rufinamide efficacy and association with phenotype and genotype in children with intractable epilepsy: A retrospective single center study

OBJECTIVE

To assess long-term efficacy and tolerability of rufinamide in children with epilepsy and a broad spectrum of underlying epileptic etiologies.

METHODS

Patients with epilepsy treated with rufinamide between 1/1/2009 and 1/1/2018 at Seattle Children's Hospital were included. Data were collected via retrospective chart review. Rufinamide efficacy was defined as seizure reduction from baseline including seizure free, >50% reduction, any reduction, no reduction, or worsening seizures. Pearson's chi-square test was used for statistical analysis.

RESULTS

183 patients (70 females and 113 males) with a broad spectrum of epileptic aetiologies (genetic/metabolic, hypoxic-ischemic, structural and others) were included. 45.9% of the patients had Lennox Gastaut syndrome. Rate of any seizure reduction was at 47.5%, seizure reduction >50% at 35%, and seizure free at 3.3%. Mean rufinamide dosage was 33.9 mg/kg/d (SD = 14.12). Mean duration of treatment was 44.48 months (SD 32.33). Suspected adverse effects occurred at 10.9%, most often as fatigue. Rufinamide achieved better seizure reduction in girls compared to boys [OR = 0.52, 95% CI (0.28, 0.97), p = 0.038]. Seizures were activated in a patient with a SCN1A mutation, fully controlled in a patient with a SCN8A mutation. Patients with certain genetic abnormalities such as DEPDC5, KCNQ2, SPATA5, and 47XYY achieved significant seizure reduction.

CONCLUSIONS

Rufinamide is an effective and well-tolerated drug for long-term treatment in pediatric patients with intractable epilepsy. Certain genotypes such as SCN8A showed good response to rufinamide. Girls seemed to respond better than boys.

Novel seizure outcomes in patients with Lennox-Gastaut syndrome: Post hoc analysis of seizure-free days in rufinamide Study 303

OBJECTIVE

Drug development for patients with Lennox-Gastaut syndrome (LGS) is based on clinical trials that use drop seizure counts. However, such counts do not assess total seizure burden and affect a patient's quality of life (QoL). In this post hoc analysis, we evaluated two novel seizure efficacy parameters related to QoL in pediatric patients with LGS, using seizure diary data from rufinamide Study 303 (NCT01405053).

METHODS

Study 303 was a phase III, multicenter, randomized, controlled, open-label study involving patients aged ≥1 to <4 years with inadequately controlled LGS. Patients were randomized 2:1 to receive add-on therapy with rufinamide or any other approved antiseizure drug (ASD), in addition to their existing treatment of 1-3 ASDs, across a 106-week treatment phase. Seizure diaries, completed by parents or caregivers, recorded seizure occurrence, and were used in this post hoc analysis to evaluate two novel efficacy parameters comparing baseline vs postbaseline mean number of seizure-free days and assessing time to reach the number of prerandomization seizures for patients receiving rufinamide or any other ASD.

RESULTS

Patients received rufinamide (n = 25) or any other ASD (n = 12). For rufinamide, mean number of seizure-free days was 42.2% greater postbaseline compared with baseline (P < 0.0001); only one rufinamide patient experienced a decrease in number of seizure-free days postbaseline. Median time to reach the baseline number of seizures increased by 10.5 days for rufinamide and 0.5 days for the any-other-ASD group during the treatment phase, to 46.0 and 54.0 days, respectively.

SIGNIFICANCE

Both of these novel and contrasting endpoints demonstrated potential improvements in seizure outcomes in patients receiving rufinamide postbaseline vs baseline. Although these parameters should be investigated in larger patient populations, our initial findings suggest that they could be applied as predefined primary endpoints for seizure assessment in future clinical trials for LGS drug development.

Topiramate: Comprehensive profile

Topiramate, 2,3:4,5-di-O-isopropylidene-β-d-fructopyranose sulfamate, is a potent antiepileptic drug with a broad spectrum of activity. It is effective in both partial and generalized seizures. Topiramate was also found to have significant efficacy in migraine prevention with considerable reductions in the frequency of migraine headaches. The most common adverse events, which may accompany the use of topiramate, are paresthesia, fatigue, decreased appetite, nausea, diarrhea, weight decrease and taste perversion. The weight loss observed with the use of topiramate in obese, epileptic patients, afforded the approval of this drug as an anti-obesity medication. This action is thought to be based on the selective inhibition of mitochondrial carbonic anhydrase isoforms. This profile is prepared to discuss and explain physical characteristics, proprietary and nonproprietary names of topiramate. It also includes methods of preparation, thermal and spectral behavior and methods of analysis. Pharmacokinetics, metabolism, excretion and pharmacology together with its uses and applications are also discussed.

Evaluation of long-term safety, tolerability, and behavioral outcomes with adjunctive rufinamide in pediatric patients (≥1 to <4 years old) with Lennox-Gastaut syndrome: Final results from randomized study 303

OBJECTIVE

Evaluate the long-term safety, tolerability, and behavioral effects of adjunctive rufinamide in pediatric patients (≥1 to <4 years old) with inadequately controlled seizures associated with Lennox-Gastaut syndrome (LGS).

METHODS

Study 303 (ClinicalTrials.gov identifier NCT01405053) was a multicenter, randomized, open-label, Phase III trial. Patients were randomized (2:1) to oral suspension rufinamide (≤45 mg/kg/day) or any other investigator-chosen antiepileptic drug (AED) for a 2-year treatment period. Primary safety/tolerability assessments included monitoring of treatment-emergent adverse events (TEAEs) and serious TEAEs. Behavioral effects were assessed via the Child Behavior Checklist (CBCL) using the Total Problems score and change from baseline in CBCL Total Problems score. CBCL subscores were also evaluated.

RESULTS

The Safety Analysis Set included 37 patients (rufinamide: n = 25; any other AED: n = 12). TEAE incidence was similar between the rufinamide (88.0%) and any-other-AED groups (83.3%); serious TEAE incidence was also similar between treatment groups (40.0% and 41.7%, respectively). Between treatment groups, the difference in the least squares mean CBCL Total Problems score across time was not significant (p = 0.7083), behavior outcomes were similar across all endpoints, and there were no consistent trends in CBCL subscores.

SIGNIFICANCE

Long-term (2 years) adjunctive rufinamide was well tolerated in pediatric patients with LGS. Behavioral outcomes were comparable between the rufinamide and any-other-AED groups, however the small sample size and difficulties assessing behavior in this population should be noted. The challenges of this study raise the issue of revising how studies in very young children with rare and complex epilepsies are performed.

Rufinamide efficacy and safety in children aged 1-4 years with Lennox-Gastaut syndrome

PURPOSE

The treatment options for Lennox-Gastaut syndrome (LGS), a pediatric epileptic syndrome, are limited, especially in younger children. Rufinamide tablets were safe and effective as an add-on treatment in Korean children and adolescents <20 years of age with LGS. This subgroup analysis aimed to evaluate the efficacy and safety of rufinamide tablets in LGS pediatric patients aged 1-4 years.

METHODS

This was a retrospective, observational study in LGS patients aged 1-4 years who received 12 weeks of treatment with rufinamide orally as an adjuvant treatment between April and June 2010. The proportion of responders (patients with a ≥50% reduction in seizure frequency after rufinamide treatment) was evaluated according to the type of seizure. The proportion of patients who were seizure-free was also evaluated. Adverse events (AEs) were evaluated after 12 weeks of treatment.

RESULTS

Among the 15 patients evaluated, one discontinued treatment because of worsening seizures 4 weeks after administration of rufinamide. Seven (46.67%) patients were responders and four patients were seizure-free. There were four responders with convulsive seizures, one each for myoclonic seizures and drop attacks, and spasms. The responder rate was increased to 69.23% by long-term treatment of rufinamide. AEs were experienced by three patients. One patient each experienced somnolence, fatigue, and rash.

CONCLUSION

Rufinamide tablets were efficacious and well tolerated in LGS patients aged 1-4 years, at doses up to 1000 mg per day, when given as add-on therapy to other antiepileptic drugs.

Pharmacokinetics and Drug Interaction of Antiepileptic Drugs in Children and Adolescents

Selecting the most appropriate antiepileptic drug (AED) or combination of drugs for each patient and identifying the most suitable therapeutic regimen for their needs is increasingly challenging, especially among pediatric populations. In fact, the pharmacokinetics of several drugs vary widely in children with epilepsy because of age-related factors, which can influence the absorption, distribution, metabolism, and elimination of the pharmacological agent. In addition, individual factors, such as seizure type, associated comorbidities, individual pharmacokinetics, and potential drug interactions, may contribute to large fluctuations in serum drug concentrations and, therefore, clinical response. Therapeutic drug concentration monitoring (TDM) is an essential tool to deal with this complexity, enabling the definition of individual therapeutic concentrations and adaptive control of dosing to minimize drug interactions and prevent loss of efficacy or toxicity. Moreover, pharmacokinetic/pharmacodynamic modelling integrated with dashboard systems have recently been tested in antiepileptic therapy, although more clinical trials are required to support their use in clinical practice. We review the mechanism of action, pharmacokinetics, drug-drug interactions, and safety/tolerability profiles of the main AEDs currently used in children and adolescents, paying particular regard to issues of relevance when treating this patient population. Indications for TDM are provided for each AED as useful support to the clinical management of pediatric patients with epilepsy by optimizing pharmacological therapy.

Safety and tolerability profile of new antiepileptic drug treatment in children with epilepsy

INTRODUCTION

Treatment of pediatric epilepsy requires a careful evaluation of the safety and tolerability profile of antiepileptic drugs (AEDs) to avoid or minimize as much as possible adverse events (AEs) on various organs, hematological parameters, and growth, pubertal, motor, cognitive and behavioral development.

AREAS COVERED

Treatment-emergent AEs (TEAEs) reported in the literature 2000-2018 regarding second- and third-generation AEDs used in the pediatric age, with exclusion of the neonatal period that exhibits specific peculiarities, have been described on the basis of their frequency, severity/tolerability, and particular association with a given AED.

EXPERT OPINION

Somnolence/sedation and behavioral changes, like irritability and nervousness, are among the most commonly observed TEAEs associated with almost all AEDs. Lamotrigine, Gabapentin, Oxcarbazepine, and Levetiracetam appear to be the best-tolerated AEDs with a ≤2% withdrawal rate, while Tiagabine and Everolimus are discontinued in up to >20% of the patients because of intolerable TEAEs. For some AEDs, literature data are scanty to draw a high-level evidence on their safety and tolerability profile. The reasons are: insufficient population size, short duration of treatments, or lack of controlled trials. A future goal is that of identifying clearer, easier, and more homogeneous methodological strategies to facilitate AED testing in pediatric populations.

Rufinamide add-on therapy for refractory epilepsy

BACKGROUND

Epilepsy is a central nervous system disorder (neurological disorder). Epileptic seizures are the result of excessive and abnormal cortical nerve cell electrical activity in the brain. Despite the development of more than 10 new antiepileptic drugs (AEDs) since the early 2000s, approximately a third of people with epilepsy remain resistant to pharmacotherapy, often requiring treatment with a combination of AEDs. In this review, we summarised the current evidence regarding rufinamide, a novel anticonvulsant medication, which, as a triazole derivative, is structurally unrelated to any other currently used anticonvulsant medication, when used as an add-on treatment for refractory epilepsy. In January 2009, rufinamide was approved by the US Food and Drug Administration for treatment of children four years of age and older with Lennox-Gastaut syndrome. It is also approved as an add-on treatment for adults and adolescents with focal seizures.

OBJECTIVES

To evaluate the efficacy and tolerability of rufinamide when used as an add-on treatment in people with refractory epilepsy.

SEARCH METHODS

On 2 October 2017, we searched the Cochrane Epilepsy Group Specialized Register, the Cochrane Central Register of Controlled Trials (CENTRAL) via the Cochrane Register of Studies Online (CRSO), MEDLINE (Ovid, 1946), ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform (ICTRP). We imposed no language restrictions. We also contacted the manufacturers of rufinamide and authors in the field to identify any relevant unpublished studies.

SELECTION CRITERIA

Randomised, double-blind, placebo-controlled, add-on trials of rufinamide, recruiting people (of any age or gender) with refractory epilepsy.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion and extracted the relevant data. We assessed the following outcomes: 50% or greater reduction in seizure frequency (primary outcomes); seizure freedom; treatment withdrawal; and adverse effects (secondary outcomes). Primary analyses were intention-to-treat (ITT) and we presented summary risk ratios (RR) with 95% confidence intervals (CI). We evaluated dose response in regression models. We carried out a risk of bias assessment for each included study using the Cochrane 'Risk of bias' tool and assessed the overall quality of evidence using the GRADE approach, which we presented in a 'Summary of findings' table.

MAIN RESULTS

The review included six trials, representing 1759 participants. Four trials (1563 participants) included people with uncontrolled focal seizures. Two trials (196 participants) included established Lennox-Gastaut syndrome. Overall, the age of the adults ranged from 18 to 80 years and the age of the infants ranged from four to 16 years. Baseline phase ranged from 28 to 56 days and double-blind phases from 84 to 96 days. Five of the six included trials described adequate methods of concealment of randomisation and only three described adequate blinding. All analyses were by ITT. Overall, five studies were at low risk of bias, and one had unclear risk of bias due to lack of reported information around study design. All trials were sponsored by the manufacturer of rufinamide, and therefore, were at high risk of funding bias.The overall RR for 50% or greater reduction in seizure frequency was 1.79 (95% CI 1.44 to 2.22; 6 RCTs; moderate-quality evidence) indicating that rufinamide (plus conventional AED) was significantly more effective than placebo (plus conventional AED) in reducing seizure frequency by at least 50%, when added to conventionally used AEDs in people with refractory focal epilepsy. The overall RR for treatment withdrawal (for any reason and due to AED) was 1.83 (95% CI 1.45 to 2.31; 6 RCTs; moderate-quality evidence) showing that rufinamide was significantly more likely to be withdrawn than placebo. In respect of adverse effects, most were significantly more likely to occur in the rufinamide-treated group. The adverse events significantly associated with rufinamide were: headache, dizziness, somnolence, vomiting, nausea, fatigue and diplopia. The RRs of these adverse effects were: headache 1.36 (95% Cl 1.08 to 1.69; 3 RCTs; high-quality evidence); dizziness 2.52 (95% Cl 1.90 to 3.34; 3 RCTs; moderate-quality evidence); somnolence 1.94 (95% Cl 1.44 to 2.61; 6 RCTs; moderate-quality evidence); vomiting 2.95 (95% Cl 1.80 to 4.82; 4 RCTs; low-quality evidence); nausea 1.87 (95% Cl 1.33 to 2.64; 3 RCTs; moderate-quality evidence); fatigue 1.46 (95% Cl 1.08 to 1.97; 3 RCTs; moderate-quality evidence); and diplopia 4.60 (95% Cl 2.53 to 8.38; 3 RCTs; low-quality evidence). There was no important heterogeneity between studies for any of the outcomes. Overall, we assessed the evidence as moderate to low quality, due to potential risk of bias from some studies contributing to the analysis and wide CIs.

AUTHORS' CONCLUSIONS

In people with drug-resistant focal epilepsy, rufinamide when used as an add-on treatment was effective in reducing seizure frequency. However, the trials reviewed were of relatively short duration and provided no evidence for the long-term use of rufinamide. In the short term, rufinamide as an add-on was associated with several adverse events. This review focused on the use of rufinamide in drug-resistant focal epilepsy and the results cannot be generalised to add-on treatment for generalised epilepsies. Likewise, no inference can be made about the effects of rufinamide when used as monotherapy.

Cognitive and Behavioral Comorbidities: An Unwanted Effect of Antiepileptic Drugs in Children

Epilepsy is one of the most common neurological disorders and, despite optimally chosen and dosed antiepileptic drugs (AEDs), approximately 20%-30% of patients will continue to have seizures. Behavior and cognition are negatively impacted by seizures, but AEDs are also a major contributor to behavioral and cognitive deficits. However, the cognitive and behavioral effect of AEDs in children is insufficiently emphasized in the literature. This review summarizes the cognitive and behavioral effects of AEDs in the pediatric population with the objective of helping pediatricians and pediatric neurologists to select the AEDs with the best profile for their individual patient's needs.

Early Diagnosis and Treatment of Lennox-Gastaut Syndrome

Lennox-Gastaut syndrome (LGS) is a severe form of childhood-onset epilepsy associated with high morbidity and mortality. The peak period for manifestations of Lennox-Gastaut syndrome is between ages 3 and 5 years, a time of critical brain development and corresponding vulnerability to the electroclinical dysfunction arising from Lennox-Gastaut syndrome. Diagnosis is based on a triad of symptoms: multiple seizure types, cognitive impairment, and slow spike-and-wave pattern on electroencephalography. In practice, Lennox-Gastaut syndrome presentation is diverse, and there may be a delay between initial symptoms and emergence of the full triad of clinical features. Additionally, differential diagnosis is complicated by the resemblance of Lennox-Gastaut syndrome to other forms of epilepsy and by the need for varied diagnostic techniques requiring specific clinical skills. Because diagnosis is complex and early intervention may lead to improved outcomes, clinicians should consider treatment when Lennox-Gastaut syndrome symptoms are present, even in the absence of a formal diagnosis.

Treatment-resistant Lennox-Gastaut syndrome: therapeutic trends, challenges and future directions

Lennox-Gastaut syndrome is a severe, childhood-onset electroclinical syndrome comprised of multiple seizure types, intellectual and behavioral disturbances and characteristic findings on electroencephalogram of slow spike and wave complexes and paroxysmal fast frequency activity. Profound morbidity often accompanies a common and severe seizure type, the drop attack. Seizures often remain refractory, or initial treatment efficacy fades. Few individuals are seizure free despite the development of multiple generations of antiseizure medications over decades and high-level evidence on several choices. Approved medications such as lamotrigine, topiramate, rufinamide, felbamate and clobazam have demonstrated efficacy in reducing seizure burden. Cannabidiol has emerged as a promising investigational therapy with vast social interest yet lacks a standard, approved formulation. Palliative surgical procedures, such as vagal nerve stimulation and corpus callosotomy may provide reduction in total seizures and drop attacks. Emerging evidence suggests that complete callosotomy provides greater improvement in seizures without additional side effects. Etiologies such as dysplasia or hypothalamic hamartoma may be amenable for focal resection and thus offer potential to reverse this devastating epileptic encephalopathy.