Current role of rufinamide in the treatment of childhood epilepsy: literature review and treatment guidelines

Discovery of triazenyl triazoles as Nav1.1 channel blockers for treatment of epilepsy

The voltage-gated sodium (Na_v) channel is one of most important targets for treatment of epilepsy, and rufinamide is an approved third-generation anti-seizure drug as Na_v1.1 channel blocker. Herein, by triazenylation of rufinamide, we reported the triazenyl triazoles as new Na_v1.1 channel blocker for treatment of epilepsy. Through the electrophysiological activity assay, compound 6a and 6e were found to modulate the inactivation voltage of Na_v 1.1 channel with shift of -10.07 mv and -11.28 mV, respectively. In the pentylenetetrazole (PTZ) mouse model, 6a and 6e reduced the seizure level, prolonged seizure latency and improved the survival rate of epileptic mice at an intragastric administration of 50 mg/kg dosage. In addition, 6a also exhibited promising effectiveness in the maximal electroshock (MES) mouse model and possessed moderate pharmacokinetic profiles. These results demonstrated that 6a was a novel Na_v1.1 channel blocker for treatment of epilepsy.

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.

Cognitive, adaptive, and behavioral effects of adjunctive rufinamide in Lennox-Gastaut syndrome: A prospective observational clinical study

INTRODUCTION

Lennox-Gastaut syndrome (LGS) is a severe pediatric epilepsy syndrome characterized by multiple drug-resistant seizure types. Children with LGS usually experience cognitive regression, and LGS is almost always associated with moderate to severe cognitive impairment. Rufinamide (RFM) was approved by the European Medicines Agency in 2007 for the adjunctive treatment of seizures associated with LGS in patients ≥4 years of age. The primary objective of our study was to assess cognitive, adaptive, and behavior functioning of patients with LGS after 12 months of RFM therapy.

METHODS

This was an observational, multicenter, prospective study involving 16 patients diagnosed with LGS aged between 7 and 58 years (mean = 22 ± 16.3). Fourteen of 16 patients were already on therapy with 3 antiseizure drugs and 2/16 with 4 antiseizure drugs; RFM has been added with 100 mg/week increments up to a dose of 300-2400 mg/day. The participants and their parents underwent a neuropsychological evaluation for the assessment of intellectual, adaptive, and emotional/behavioral functioning (Leiter International Performance Scale-Revised (LEITER-R), Vineland, and Child Behavior CheckList (CBCL), respectively) before the RFM introduction (baseline) and 12 months after the RFM therapy (T2). Physical and neurological examination, electroencephalography (EEG) recording, seizure type and frequency, and adverse reactions were also considered.

RESULTS

After 12 months, the total intelligence quotient (IQ) assessed by LEITER-R did not show statistical significant changes, such as there were no statistically significant changes in adaptive functions, assessed by Vineland. Furthermore, there were no statistically significant changes in internalizing and externalizing problems assessed by CBCL.

CONCLUSION

Adjunctive treatment with RFM did not negatively affect cognitive, adaptive function, and emotional profile in patients with LGS after 1 year of follow-up.

Rufinamide as add-on therapy in children with epileptic encephalopathies other than Lennox-Gastaut syndrome: A study of 34 patients

OBJECTIVE

Here, we present a multicenter series of patients with developmental and epileptic encephalopathies (DEE) and related electroclinical patterns (REP) other than Lennox-Gastaut syndrome (LGS) who were treated with rufinamide as add-on therapy.

METHODS

Medical records of 34 patients with DEE and REP other than LGS treated with add-on rufinamide seen at four pediatric neurology centers in Argentina between May 2014 and March 2019 were retrospectively analyzed.

RESULTS

We evaluated 34 patients (18 males, 16 females), aged between 2 and 15 years with a mean and median age of 6 and 8 years, respectively. The children had different types of childhood-onset refractory DEE and REP other than LGS and were treated with rufinamide for a mean period of 20 months (range, 12-60 months). Twenty-two of 34 patients (64.5%) who received rufinamide as add-on therapy had a greater than 50% decrease in seizures, and two patients (5.8%) became seizure-free. Four patients (11.7%) had a 25-50% seizure reduction, while seizure frequency remained unchanged in four others (11.7%) and increased in two patients (5.8%). The final mean dosage of rufinamide was 31.5 ± 15.5 mg/kg per day (range, 19-75.4 mg/kg) if combined with valproic acid and of 35.4 ± 11.5 mg/kg per day (range, 8-60.5 mg/kg) without valproic acid. Adverse effects were recorded in nine patients (26.4%). A seizure increase was reported in two of 24 patients (7.3%).

CONCLUSION

Rufinamide may be used as a treatment option in DEE and REP other than LGS.

Pharmacotherapy for Focal Seizures in Children and Adolescents

Focal-onset seizures are among the most common forms of seizures in children and adolescents and can be caused by a wide diversity of acquired or genetic etiologies. Despite the increasing array of antiseizure drugs available, treatment of focal-onset seizures in this population remains problematic, with as many as one-third of children having seizures refractory to medications. This review discusses contemporary concepts in focal seizure classification and pathophysiology and describes the antiseizure medications most commonly chosen for this age group. As antiseizure drug efficacy is comparable in children and adults, here we focus on pharmacokinetic aspects, drug-drug interactions, and side effect profiles. Finally, we provide some suggestions for choosing the optimal medication for the appropriate patient.

Pharmacokinetic considerations for anti-epileptic drugs in children

INTRODUCTION

Epilepsy is a chronic and debilitating neurological disease, with a peak of incidence in the first years of life. Today, the vast armamentarium of antiepileptic drugs (AEDs) available make even more challenging to select the most appropriate AED and establish the most effective dosing regimen. In fact, AEDs pharmacokinetics is under the influence of important age-related factors which cannot be ignored. Areas covered: Physiological changes occurring during development age (different body composition, immature metabolic patterns, reduced renal activity) can significantly modify the pharmacokinetic profile of AEDs (adsorption, volume of distribution, half-life, clearance), leading to an altered treatment response. We reviewed the main pharmacokinetic characteristics of AEDs used in children, focusing on age-related factors which are of relevance when treating this patient population. Expert opinion: To deal with this pharmacokinetic variability, physicians have at their disposal two tools: 1) therapeutic drug concentration monitoring, which may help to set the optimal therapeutic regimen for each patient and to monitor eventual fluctuation, and 2) the use of extended-release drug formulations, when available. In the next future, the development of 'ad-hoc' electronic dashboard systems will represent relevant decision-support tools making the AED therapy even more individualized and precise, especially in children.

Real-world data on rufinamide treatment in patients with Lennox-Gastaut syndrome: Results from a European noninterventional registry study

INTRODUCTION

Rufinamide is approved for the adjunctive treatment of seizures associated with Lennox-Gastaut syndrome (LGS) in patients aged ≥4years. The objective of this study was to provide real-world, long-term data on patients with LGS initiating rufinamide as add-on therapy and patients with LGS receiving other antiepileptic drugs (AEDs).

METHODS

A Phase IV, noninterventional, multicenter registry study was conducted in patients with LGS aged ≥4years requiring modification to any AED treatment, including initiation of add-on rufinamide therapy. Safety/tolerability was assessed by evaluating treatment-emergent adverse events (TEAEs), and efficacy was assessed using a generic seizure frequency scale.

RESULTS

A total of 111 patients from 64 sites in 8 European countries were included, of whom 64 initiated rufinamide ("rufinamide" group) and 21 did not receive rufinamide at any time during the study ("no-rufinamide" group). Mean ages were 16.1years (rufinamide) and 15.0years (no rufinamide). The median duration of follow-up was >2years (range: 1.3-46.4months). Antiepileptic drug-related TEAEs were reported for 40.6% (rufinamide) and 33.3% (no rufinamide) of patients and led to discontinuation of 7.8% and 4.8%, respectively. The most frequently reported rufinamide-related TEAEs (≥5% patients) were somnolence (7.8%) and decreased appetite (6.3%). There were no unexpected safety/tolerability findings. At month 12, the proportion of patients with improvement in all seizures ("much improved" or "very much improved") was 28.6% (12/42) for the rufinamide group and 14.3% (2/14) for the no-rufinamide group.

CONCLUSION

The study provided valuable information on LGS and its management, and evidence that rufinamide has a consistent and generally favorable safety/tolerability profile when used in routine clinical practice. CLINICALTRIALS.

GOV IDENTIFIER

NCT01991041.

Cognitive and behavioral effects of new antiepileptic drugs in pediatric epilepsy

BACKGROUND

In pediatric epilepsy, neurodevelopmental comorbidities could be sometimes even more disabling than seizures themselves, therefore it is crucial for the clinicians to understand how to benefit these children, and to choose the proper antiepileptic drug for the treatment of epilepsy associated to a specific neurodevelopmental disorder. Aim of this paper is to discuss the potential impact on cognition and behavior of new and newest AEDs and to guide the choice of the clinicians for a targeted use in epilepsy associated with specific neurodevelopmental disorders.

METHODS

Information in this review is mainly based on peer-reviewed medical publications from 2002 until October 2016 (PubMed). We choose to include in our review only the AEDs of second and third generation approved for pediatric population.

RESULTS

Vigabatrin, lamotrigine, topiramate, levetiracetam, oxcarbazepine, zonisamide, rufinamide, lacosamide, eslicarbazepine, and perampanel have been included in this review. The most tolerated AEDs from a cognitive and behavioral point of view are lamotrigine and rufinamide, thus representing optimal drugs for children with cognitive and/or attention problems.

DISCUSSION

Most of the new AEDs are initially licensed for adult patients. Data on children are usually very limited, both in terms of efficacy and safety, and the use standardized cognitive and behavioral outcome measures are very limited in pediatric clinical trials.

CONCLUSION

Several factors including polytherapy, administration of AEDs with the same mechanism of action and the dose and titration of the drug, should be considered as important in the development of cognitive and behavioral side effects.

Epilepsy, Antiepileptic Drugs, and Aggression: An Evidence-Based Review

Antiepileptic drugs (AEDs) have many benefits but also many side effects, including aggression, agitation, and irritability, in some patients with epilepsy. This article offers a comprehensive summary of current understanding of aggressive behaviors in patients with epilepsy, including an evidence-based review of aggression during AED treatment. Aggression is seen in a minority of people with epilepsy. It is rarely seizure related but is interictal, sometimes occurring as part of complex psychiatric and behavioral comorbidities, and it is sometimes associated with AED treatment. We review the common neurotransmitter systems and brain regions implicated in both epilepsy and aggression, including the GABA, glutamate, serotonin, dopamine, and noradrenaline systems and the hippocampus, amygdala, prefrontal cortex, anterior cingulate cortex, and temporal lobes. Few controlled clinical studies have used behavioral measures to specifically examine aggression with AEDs, and most evidence comes from adverse event reporting from clinical and observational studies. A systematic approach was used to identify relevant publications, and we present a comprehensive, evidence-based summary of available data surrounding aggression-related behaviors with each of the currently available AEDs in both adults and in children/adolescents with epilepsy. A psychiatric history and history of a propensity toward aggression/anger should routinely be sought from patients, family members, and carers; its presence does not preclude the use of any specific AEDs, but those most likely to be implicated in these behaviors should be used with caution in such cases.

Pharmacokinetics and Tolerability of Rufinamide Following Single and Multiple Oral Doses and Effect of Food on Pharmacokinetics in Healthy Chinese Subjects

BACKGROUND

Rufinamide is a triazole derivative that is structurally unrelated to currently marketed antiepileptic medications for add-on treatment of seizures in the setting of Lennox-Gastaut syndrome in patients from the age of 4 years.

OBJECTIVE

The purpose of this study was to determine the pharmacokinetic and safety profile of single and multiple doses of rufinamide in healthy Chinese subjects. The effects of food and gender on the pharmacokinetic properties of rufinamide were also evaluated.

METHODS

In the single-dose study, volunteers were randomly assigned to 4 dose groups and received a single dose of 200, 400, 800, 1200 mg rufinamide tablets under fasting condition. Ten subjects in the 200-mg dose group were randomly assigned to either a high-fat or non-high-fat breakfast group in each study period. The drug administration was separated by a washout period of 7 calendar days. In the multiple-dose study, 10 subjects were administered on an empty stomach rufinamide 200 mg twice daily for 6 consecutive days. Liquid chromatography tandem mass spectrometry (LC-MS/MS) method was applied to determine plasma concentration of rufinamide. Pharmacokinetic parameters, including the maximum plasma concentration (C max), the time to peak concentration (t max), the area under the plasma concentration versus time curve from time 0 to the last measurable concentration (AUC0-t ) and from time 0 to infinity (AUC0-∞), terminal elimination half-life (t 1/2), apparent volume of distribution (V d), apparent clearance (CL), average residence time (MRT), area under the plasma concentration versus time curve from time 0 to the last measurable concentration at steady state (AUCss), peak concentration (C max,ss) and trough level concentration (C min,ss) at steady state were calculated using non-compartmental models. Tolerability was assessed based on investigator inquiries, spontaneous reports and clinical evaluations.

RESULTS

Rufinamide displayed a dose-dependent, but sub-proportional increase in exposure following single-dose and repeated dose administration. After administration of single dose of 200, 400, 800 and 1200 mg, without food, the rufinamide mean C max (standard deviation, SD) was 1806.5 (526.4), 2490 (564.8), 3719 (976.1) and 4166 (1187.1) μg/L, respectively. Mean AUC0-t (SD) was 34,571 (9484), 56,246 (18,077), 89,022 (23,379) and 107,316 (34,766) μg·h/L, respectively. While in fed condition at the dosage of 200 mg, mean C max (SD) and mean AUC0-t (SD) were 2363 (582) μg/L and 40,593 (10,516) μg·h/L, respectively. After administration of multiple doses, arithmetic mean (SD) values of C max and AUC0-t were 3566 (873) μg/L and 62,803 (19,873) μg·h/L, respectively. The steady state was achieved by day 3 of multiple dosing after 2 daily doses (twice a day), the corresponding accumulation factor (AUCss/AUC0-t) was 0.9057. Although there were no substantial effects on exposure resulting from gender differences, a notable food effect was observed, with AUC and C max increased by 17.4 and 30.8 %, respectively. Single- and multiple-dose phases were generally safe and well tolerated.

CONCLUSION

Overall, 15 % (6/40) of subjects experienced a mild indisposition with no serious adverse events. On single and multiple dosing, rufinamide exhibited nonlinear pharmacokinetics and was well tolerated in healthy Chinese subjects.

Rufinamide in children and adults in routine clinical practice

OBJECTIVE

To explore the long-term effectiveness of rufinamide in managing Lennox-Gastaut Syndrome (LGS), other epileptic encephalopathies, and intractable focal epilepsies in adults and children in routine clinical practice.

METHODS

A multicentre, retrospective chart review of patients prescribed adjunctive rufinamide at seven Spanish epilepsy centres, with assessments at six and 12 months.

RESULTS

We evaluated data from 58 patients (40 male, age range 7-57 years), 25 of whom were diagnosed with LGS, 12 with other epileptic encephalopathies and 21 of whom were diagnosed with focal epilepsies, mainly frontal lobe. The mean daily rufinamide dose was 32.0 mg/kg (range 12.5-66.7 mg/kg) in children and 24.7 mg/kg (range 5.0-47.0 mg/kg) in adults, and the most commonly used concomitant antiepileptic drugs were levetiracetam and valproate. Rufinamide was discontinued in 25 patients (43.1%) during the 1-year follow-up, and the most common reason was lack of effectiveness (n = 12, 20.7% of total). The frequency of generalized tonic-clonic seizures was significantly reduced from baseline at 6 and 12 months (P = 0.001), both in patients with generalized epilepsies and in patients with focal epilepsies. Significant seizure frequency reduction from baseline was observed at 12 months (P = 0.01) for tonic/atonic seizures and at 6 months (P = 0.001) for focal seizures. Side effects were reported in 21 patients (36.2%): nausea, vomiting and weight loss were most frequent.

CONCLUSIONS

Rufinamide was well tolerated and was effective in reducing frequency of generalized tonic-clonic, tonic/atonic and focal seizures in both children and adults with severe refractory epilepsies, primarily LGS.

Aggravation of atonic seizures by rufinamide: A case report

BACKGROUND

Rufinamide is a novel antiepileptic drug used as adjunctive therapy in patients with Lennox-Gastaut syndrome and provides seizure control especially in tonic and atonic seizures. Rufinamide is expected to be effective in intractable epilepsy when atonic and tonic seizures exist. However, rufinamide induced seizure aggravation has been reported in a few patients, which was not associated with a specific type of seizure.

CASE

A 12-year-old boy with intractable epilepsy had tonic and atonic seizures despite treatment with valproic acid (3000mg/day), levetiracetam (3000mg/day) and clobazam (40mg/day). Rufinamide was administered as adjuvant therapy. After 2weeks on rufinamide, he experienced atonic seizure worsening, and the frequency of epileptic discharges increased. The deterioration in seizure frequency and epileptiform discharges resolved when rufinamide was discontinued.

CONCLUSION

Rufinamide may aggravate atonic seizures in patients with intractable epilepsy.

Treatment of Adults with Lennox-Gastaut Syndrome: Further Analysis of Efficacy and Safety/Tolerability of Rufinamide

INTRODUCTION

Management of Lennox-Gastaut syndrome (LGS) in adulthood can be particularly challenging. Published reports describing the use of rufinamide specifically in adult patients with LGS are scarce. A post hoc subgroup analysis of data from a phase III trial was conducted to investigate the efficacy and safety/tolerability of rufinamide in adults with LGS.

METHODS

A randomized, double-blind, placebo-controlled trial was conducted in patients with LGS, aged 4 years and above. During an 84-day, double-blind treatment period, patients received either adjunctive rufinamide therapy or placebo. Efficacy and safety/tolerability were assessed in a post hoc subgroup analysis of adult patients (≥18 years). Efficacy was assessed as change from baseline in 28-day seizure frequency, 50% responder rate, and seizure freedom rate; each calculated for total seizures and drop attacks. Safety/tolerability assessments included the evaluation of adverse events (AEs).

RESULTS

Thirty-one adults aged 18-37 years with LGS received treatment with either rufinamide (n = 21) or placebo (n = 10). Three patients in the rufinamide group did not complete the trial. The median change from baseline in seizure frequency was -31.5% for rufinamide versus +22.1% for placebo (P = 0.008) for all seizures and -54.9% versus +21.7% (P = 0.002) for drop attacks. Responder rates were 33.3% for rufinamide versus 0% for placebo (P = 0.066) for all seizures and 57.1% versus 10.0% (P = 0.020) for drop attacks. No patient achieved freedom from all seizures but two rufinamide-treated patients (9.5%) became free of drop attacks. Overall, 71.4% of patients treated with rufinamide and 60.0% of patients treated with placebo experienced AEs; most commonly, somnolence (33.3% vs. 20.0%) and vomiting (19.0% vs. 0%). Most AEs were of mild or moderate intensity.

CONCLUSION

Rufinamide demonstrated favorable efficacy and was generally well tolerated when used as adjunctive treatment for adults with LGS.

FUNDING

Eisai.

Retention rates of rufinamide in pediatric epilepsy patients with and without Lennox-Gastaut Syndrome

OBJECTIVE

To evaluate the effectiveness of rufinamide (RFM) in patients with Lennox-Gastaut Syndrome (LGS) compared to those with other epilepsy syndromes using time to treatment failure (retention rate) as the outcome measure.

METHODS

In this retrospective cohort study, characteristics and outcomes of all patients receiving RFM in 2009 and 2010 were recorded. The primary outcome measure was RFM failure, defined as discontinuation of RFM or initiation of an additional antiepileptic therapy. The secondary outcome measure was discontinuation of RFM. Kaplan-Meier method survival curves were generated for time to RFM failure, for all patients and by the presence or absence of Lennox Gastaut Syndrome (LGS). The impact of age, seizure type, fast or slow drug titration, and concomitant therapy with valproate on retention rate were evaluated using Cox regression models.

RESULTS

One hundred thirty-three patients were included, 39 (30%) of whom had LGS. For all patients, the probability of remaining on RFM without additional therapy was 45% at 12 months and 30% at 24 months. LGS diagnosis was an independent predictor of time to RFM failure (HR 0.51, 95% CI 0.31-0.83), with a median time to failure of 18 months in LGS compared to 6 months in all others (p=0.006).

CONCLUSIONS

In a broad population of children with refractory epilepsy, around half will continue taking the medication for at least a year without additional therapy. Patients with LGS are two times more likely to continue RFM without additional therapy compared to those without LGS.