Rufinamide for the treatment of epileptic spasms

Research Status, Synthesis and Clinical Application of Antiepileptic Drugs

According to the 2017 ILAE's official definition, epilepsy is a slow brain disease state characterized by recurrent episodes. Due to information released by ILAE in 2017, it can be divided into four types, including focal epilepsy, generalized epilepsy, combined generalized, and focal epilepsy, and unknown epilepsy. Since 1989, 24 new antiepileptic drugs have been approved to treat different types of epilepsy. Besides, there are a variety of antiepileptic medications under clinical monitoring. These novel antiepileptic drugs have plenty of advantages. Over the past 33 years, there have been many antiepileptic drugs on the mearket, but no one has been found that can completely cure epilepsy. In this paper, the mentioned drugs were classified according to their targets, and the essential information, and clinical studies of each drug were described. The structure-activity relationship of different chemical structures was summarized. This paper provides help for the follow-up research on epilepsy drugs.

Epileptic spasms in CDKL5 deficiency disorder: Delayed treatment and poor response to first-line therapies

OBJECTIVE

We aimed to assess the treatment response of infantile-onset epileptic spasms (ES) in CDKL5 deficiency disorder (CDD) vs other etiologies.

METHODS

We evaluated patients with ES from the CDKL5 Centers of Excellence and the National Infantile Spasms Consortium (NISC), with onset from 2 months to 2 years, treated with adrenocorticotropic hormone (ACTH), oral corticosteroids, vigabatrin, and/or the ketogenic diet. We excluded children with tuberous sclerosis complex, trisomy 21, or unknown etiology with normal development because of known differential treatment responses. We compared the two cohorts for time to treatment and ES remission at 14 days and 3 months.

RESULTS

We evaluated 59 individuals with CDD (79% female, median ES onset 6 months) and 232 individuals from the NISC database (46% female, median onset 7 months). In the CDD cohort, seizures prior to ES were common (88%), and hypsarrhythmia and its variants were present at ES onset in 34%. Initial treatment with ACTH, oral corticosteroids, or vigabatrin started within 1 month of ES onset in 27 of 59 (46%) of the CDD cohort and 182 of 232 (78%) of the NISC cohort (p < .0001). Fourteen-day clinical remission of ES was lower for the CDD group (26%, 7/27) than for the NISC cohort (58%, 106/182, p = .0002). Sustained ES remission at 3 months occurred in 1 of 27 (4%) of CDD patients vs 96 of 182 (53%) of the NISC cohort (p < .0001). Comparable results were observed with longer lead time (≥1 month) or prior treatment. Ketogenic diet, used within 3 months of ES onset, resulted in ES remission at 1 month, sustained at 3 months, in at least 2 of 13 (15%) individuals with CDD.

SIGNIFICANCE

Compared to the broad group of infants with ES, children with ES in the setting of CDD often experience longer lead time to treatment and respond poorly to standard treatments. Development of alternative treatments for ES in CDD is needed.

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.

Potential induction of epileptic spasms by nonselective voltage-gated sodium channel blockade: Interaction with etiology

PURPOSE

Epileptic spasms are often preceded by focal (or multifocal) seizures. Based on a series of case reports suggesting that carbamazepine and oxcarbazepine may induce epileptic spasms, we set out to rigorously evaluate the potential association between exposure to voltage-gated sodium channel blockade and latency to epileptic spasms.

METHODS

We identified 50 cases (children with focal seizures and evolution to epileptic spasms) and 50 controls (children with focal seizures without evolution to epileptic spasms). For each patient, we reviewed all sequential neurology encounters between onset of epilepsy and emergence of epileptic spasms. For each encounter we recorded seizure-frequency and all anti-seizure therapy exposures. Using multivariable Cox proportional hazards regression, we evaluated the association between voltage-gated sodium channel exposure (carbamazepine, oxcarbazepine, lacosamide, or phenytoin) and latency to epileptic spasms onset, with adjustment for etiology and seizure-frequency.

RESULTS

Latency to epileptic spasms onset was independently associated with exposure to sodium channel blockade (hazard ratio = 2.4; 95% CI 1.1-5.2; P = 0.03) and high-risk etiology (hazard ratio = 2.8; 95% CI 1.5-5.1; P = 0.001). With assessment for interaction between sodium channel blockade and etiology, we identified an estimated 7-fold increased risk of epileptic spasms with the combination of sodium channel blockade and high-risk etiology (hazard ratio = 7.0, 95% CI 2.5-19.8; P < 0.001).

CONCLUSION

This study suggests that voltage-gated sodium channel blockade may induce epileptic spasms among children at risk on the basis of etiology. Further study is warranted to replicate these findings, ascertain possible drug- and dose-specific risks, and identify potential mechanisms of harm.

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.

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.

Efficacy of ketogenic diet for infantile spasms: A systematic review

The aim of this systematic review was to collect and analyze all the RCTs and observational studies investigating the efficacy of ketogenic diet (KD) in infantile spasms (IS) patients after a 1- to 6-month follow-up period, in terms of decrease in seizure frequency of >50% or a seizure-free interval. Moreover, the potential effect of gender, IS etiology, age at onset of IS, and age at start of KD have been investigated. Finally, we evaluated the seizure-free rate at 12 and 24 months of follow-up. In June 2016, a computer search was performed on MedLine (PubMed), EMBASE, and the Cochrane Library. Only, English language studies conducted after 1980 and those reporting in detail the variation in seizure frequency have been selected. Thirteen observational studies (341 patients) were included in the final analysis. A median rate of 64.7% of patients experienced a spasm reduction >50% (IQR: 38.94%). The median spasm-free rate was 34.61% (IQR: 37.94%). IS of unknown etiology seemed to have an increased probability of achieving freedom from seizures (RR: 1.72, 95%CI: 1.18-2.53). Long-time follow-up data revealed a median seizure-free rate of 9.54% (IQR: 18.23%). Although the literature is still lacking in high-quality studies, which could provide a stronger level evidence, our findings suggest a potential benefit of KD for drug-resistant IS patients.

Successful Treatment of Refractory Seizures With Rufinamide in Children With Schizencephaly: Report of 3 Cases

Schizencephaly is an uncommon malformation of cortical development. Patients with schizencephaly present with a broad range of severe neurologic symptoms including pharmacoresistant epilepsy. Rufinamide is a new antiepileptic drug approved for use as adjunctive therapy of seizures associated with Lennox-Gastaut syndrome and it is also effective for refractory partial seizures. We report 3 cases of pediatric patients aged 7.2, 8.1, and 10.1 years, respectively, with intractable epilepsy associated with bilateral open-lip schizencephaly and septo-optic dysplasia. The follow-up ranged from 3.8 to 4.1 years. In our patients, the introduction of rufinamide as adjunctive drug led to a dramatic decline in the number of seizures and an improvement in EEG epileptic activity without side effects. Rufinamide seems to be efficacious and safe in patients with epileptic encephalopathies associated with pharmacoresistant epilepsy; further and larger clinical reports and controlled studies could confirm the usefulness of this anticonvulsant drug.

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.

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

PURPOSE

The literature on the efficacy and safety of rufinamide in childhood-onset epilepsy syndromes currently includes approximately 600 paediatric patients. This paper summarizes the views of a panel of experienced European epileptologists with regard to the current role of rufinamide in the treatment of childhood epilepsies.

RESULTS

Rufinamide is effective in decreasing the seizure frequency in the Lennox-Gastaut syndrome (LGS), especially tonic and atonic seizures. It might consequently be preferred to other drugs as a second-line treatment for LGS when drop-attacks are frequent. The mean responder rate in the published studies is 38% with seizure freedom achieved in 2.4% of patients. Rufinamide has shown some efficacy in epileptic encephalopathies other than LGS. It can be also effective as adjunctive therapy in children and adolescents with drug-resistant partial seizures. The available data suggest that rufinamide has an acceptable risk/benefit ratio with quite a low risk of aggravating seizures. Common adverse effects (somnolence, nausea and vomiting) are usually mild and self-limiting; they are more frequently observed during titration than in the maintenance phase, suggesting that low escalation rates might be associated with fewer adverse effects. Rufinamide appears to have a favourable cognitive profile compared with other antiepileptic drugs.

CONCLUSION

Rufinamide is only approved for adjunctive treatment of seizures associated with LGS in children 4 years of age and older. There are very few data on rufinamide treatment at the onset of LGS or early in the course of the disorder; whether early treatment will improve outcome has yet to be determined.

Newer antiepileptic drugs: evidence based use

Several new antiepileptic drugs (AED's) have been approved by the FDA in the last 2 decades. The newer AED's score over the older ones, in terms of improved tolerability, safety, improved pharmacokinetics and lower drug-drug interactions. However, efficacy may not be significantly higher. This article reviews the newer antiepileptics approved in the pediatric age group and the evidence for or against their clinical use.

Efficacy and safety of rufinamide in children under four years of age with drug-resistant epilepsies

BACKGROUND

Studies on the efficacy and tolerability of rufinamide in infants and young children are scarce. Here we report on an open, retrospective, and pragmatic study about safety and efficacy of rufinamide in children aged less than four years, in terms of seizures types and epilepsy syndromes.

METHODS

Forty children (mean age 39.5 months; range 22-48) were enrolled in the study. The mean follow-up period was 12.2 months (range 5-21). Rufinamide was initiated at a mean age of 26.7 months (range 12-42). Final rufinamide mean dosage was 31.5 mg/kg/day if associated with valproic acid and 44.2 mg/kg/day if not.

RESULTS

The highest seizure reduction rate was observed in the epileptic spasms (46%) and drop attacks (42%) groups. Seizure reduction was also observed in tonic seizures (35%) and in the focal seizure (30%) groups. In terms of epilepsy syndrome, rufinamide was effective in Lennox-Gastaut syndrome. Results were very poor for those affected by Dravet's syndrome. Globally, responder rate was 27.5%, including two (5%) patients seizure-free. Adverse reactions occurred in 37.5% of children and were mainly represented by vomiting, drowsiness, irritability, and anorexia. Discontinuation rate due to treatment-emergent adverse events was 15%.

CONCLUSION

The present study concludes that rufinamide may be a safe and effective drug for a broad range of seizures and epilepsy syndromes in infants and young children and represents a valid therapeutic option in this population.

Epileptic spasms in tuberous sclerosis complex

PURPOSE

To characterize epileptic spasms (ES) occurring after the age of two years in patients with tuberous sclerosis complex (TSC), particularly treatment response to vigabatrin (VGB), which is extremely effective for infantile spasms (IS) in TSC.

METHODS

The authors retrospectively reviewed 19 patients with TSC and ES. Medical records were assessed for clinical and treatment data, neurocognitive, EEG, MRI data, and genetic analyses.

RESULTS

Of 391 patients with TSC, 19 (4.8%) had ES. Of those with detailed clinical data, six had infantile spasms that persisted after 2 years old, six recurred after an initial remission of infantile spasms (range 2-24 years old), and four occurred de novo over the age of two (range 2-20 years old). All concurrently had other seizure types. One had hypsarrhythmia on EEG. All had brain MRI stigmata typical of TSC. Thirteen had a mutation in TSC2, and one in TSC1. Six patients became spasm-free with medication treatment, including four with VGB, one with VGB in combination with the low glycemic index dietary treatment, and one with felbamate. Five became spasm-free after epilepsy surgery. VGB was not effective for seven patients. The majority continued to have refractory epilepsy.

CONCLUSIONS

ES are not uncommon in patients with TSC, especially those with TSC2 mutations. ES in TSC occur in the setting of other seizure types and refractory epilepsy. Hypsarrhythmia is rare. VGB can be effective, but the success of VGB for ES in TSC is not equivalent to that of IS in TSC.

Efficacy and safety of rufinamide in pediatric epilepsy

Rufinamide is a novel anticonvulsant medication approved by the US Food and Drug Administration (FDA) in 2008 for the treatment of seizures associated with Lennox-Gastaut syndrome in patients 4 years of age and older, based upon clinical trials demonstrating clinical efficacy and tolerability. Rufinamide is especially effective for tonic-atonic seizures in Lennox-Gastaut syndrome, but is subsequently proving to be safe and effective in clinical practice for a broad patient population with refractory epilepsy. Although further research and clinical experience is needed, rufinamide holds the promise to positively impact the care of children with epilepsy. In this review, we review the use of rufinamide in pediatric epilepsy, with a focus on efficacy and safety.

First long-term experience with the orphan drug rufinamide in children with myoclonic-astatic epilepsy (Doose syndrome)

INTRODUCTION

We evaluated the long-term efficacy and tolerability of the orphan drug rufinamide (RUF) in children with pharmacoresistant myoclonic-astatic epilepsy (MAE, Doose syndrome).

METHODS

This was a retrospective European multicenter study on eight patients who had started an intention-to-treat trial of RUF between July 2007 and June 2010. Clinical information was collected via questionnaire. Responder rate was defined as reduction of seizure frequency ≥50% in comparison to four weeks before starting RUF. Maximum follow-up was eighteen months.

RESULTS

Responder rates were 7/8 patients after 3 months, 6/8 patients after 6 months and 5/8 patients after 12 months. RUF seemed particularly effective in the prevention of myoclonic-astatic seizures (comparable with drop attacks in Lennox-Gastaut-Syndrome, for which RUF is particularly effective). Some loss of efficacy was noticed in the long-term observation. Side-effects occurred in two patients. Seizure aggravation was not observed.

CONCLUSION

RUF seems to be a promising therapeutic option in children with MAE. Further studies are warranted to confirm these first observations.

Rufinamide efficacy and safety as adjunctive treatment in children with focal drug resistant epilepsy: the first Italian prospective study

Rufinamide is a new antiepileptic drug approved as add-on treatment in Lennox-Gastaut syndrome from the age of 4 years, and for the treatment of focal seizures in adults and adolescents. The aim of this prospective study was to evaluate the safety and efficacy of add-on Rufinamide in the treatment of childhood focal drug resistant epilepsy. We recruited 70 patients for a prospective, add-on, open-label study. Inclusion criteria were: 3 years of age or more; focal drug resistant epilepsy despite the use of three previous AEDs; use of at least one other AED, but no more than three at baseline; more than one seizure per month in the previous 6 months. Rufinamide efficacy was observed up to 12 months of follow-up, with a total responder rate of 38.57%. We found the best results in focal epilepsies due to structural/metabolic etiology (42.6%). The responder rate was similar for focal seizures with secondary generalization, simple focal seizures other than myoclonic jerks, and complex partial seizures. Response to Rufinamide was not related to the age. Our experience suggests that Rufinamide can be effective in reducing focal seizure frequency in children with drug resistant epilepsy, and that it can be considered as a safe drug.

Rufinamide as an adjuvant treatment in children with Lennox-Gastaut syndrome

PURPOSE

To evaluate the efficacy of rufinamide as an add-on treatment in children and adolescents with Lennox-Gastaut syndrome (LGS).

METHODS

The study was an open-label, observational clinical trial of rufinamide as an add-on treatment in intractable LGS patients. This intent-to-treat trial included 4 weeks of scheduled titrated doses and a 12-week maintenance phase with a target dose of 20-40 mg/kg rufinamide, adjusted according to its effectiveness and tolerability after a baseline period of 4 weeks. The primary outcome was measured by the seizure-reduction rate according to individual seizure type over the 12-week maintenance period.

RESULTS

One hundred and twenty-eight patients with LGS who were determined to be unresponsive to one or more antiepileptic drugs or dietary therapy were enrolled. Of the 128 patients enrolled, 112 (87.5%) completed the study. After add-on rufinamide treatment, 46 patients (35.9%) achieved a more than 50% reduction in seizure frequency and 10 (7.8%) patients became seizure-free. When we identified those who responded with an at least 50% reduction in seizure frequency, 39.4% of the responders reported reductions in convulsive seizures, 36.4% in drop attacks, 33.3% in myoclonic seizures, and 20.0% in epileptic spasms. Overall, 32.8% of patients reported adverse effects, which were mostly mild and transient in nature. The most common adverse effects were fatigue (15 patients, 11.7%) and poor appetite (9 patients, 7.0%). Twenty-one (16.4%) patients experienced an increased seizure frequency.

CONCLUSIONS

Rufinamide appears to be a safe and effective adjuvant treatment for many cases of intractable LGS.

Low long-term efficacy and tolerability of add-on rufinamide in patients with Dravet syndrome

In this retrospective European multicenter study we evaluated the efficacy and tolerability of rufinamide in patients with Dravet syndrome and refractory seizures. Twenty patients were included; in 16 patients a SCN1A mutation was detected. The responder rate after 6 months was 20%, and after 34 months, 5%. The retention rate was 45% after 6 months and 5% after 34 months. Rufinamide treatment was stopped because of aggravation of seizures (30%), no effect (45%), and side effects (10%). The efficacy and long-term retention rate were low in our patients with Dravet syndrome and refractory seizures, far lower than in patients with Lennox-Gastaut syndrome; one-third of our patients experienced seizure aggravation. Therefore, rufinamide does not seem to be a suitable option for long-term treatment in patients with Dravet syndrome.

Update on rufinamide in childhood epilepsy

Rufinamide is an orally active, structurally novel compound (1-[(2,6-difluorophenil1) methyl1]-1 hydro 1,2,3-triazole-4 carboxamide), which is structurally distinct from other anticonvulsant drugs. It was granted orphan drug status for the adjunctive treatment of Lennox-Gastaut syndrome (LGS) in the United States in 2004, and released for use in Europe in 2007. In January 2009, rufinamide was approved by the United States Food and Drug Administration for treatment of LGS in children 4 years of age and older. It is also approved for adjunctive treatment for partial seizures in adults and adolescents. Rufinamide's efficacy mainly against atonic/tonic seizures in patients with LGS seems nowadays indubitable and has been confirmed both in randomized controlled trial and in open label extension studies. More recently, rufinamide was evaluated for the adjunctive treatment of childhood-onset epileptic encephalopathies and epileptic syndromes other than LGS, including epileptic spasms, multifocal epileptic encephalopathy with spasm/tonic seizures, myoclonic-astatic epilepsy, Dravet syndrome and malignant migrating partial seizures in infancy. This review updates the existing literature data on the efficacy and safety/tolerability of rufinamide in childhood-onset epilepsy syndromes.