Sulthiame add-on therapy in children with Lennox-Gastaut syndrome: A study of 44 patients

Sulthiame use in children with pharmacoresistant epilepsies: A retrospective study

OBJECTIVE

This retrospective study aimed to assess the efficacy and tolerability of sulthiame as an add-on treatment in children with pharmacoresistant epilepsies.

METHODS

All patients with epilepsy who received sulthiame at Montreal Children's Hospital over an 11-year period were included. Medical charts were reviewed, and extracted data included patient age and sex, seizure types, epilepsy syndrome, electroencephalography (EEG) reports, brain imaging reports, antiseizure treatments trialed, starting and final dose of sulthiame, duration of sulthiame treatment, adverse events attributed to sulthiame, and seizure frequency before and after sulthiame treatment. EEG studies were also analyzed and spike-wave index (SWI) in the first 10 min of sleep was calculated.

RESULTS

Sixteen patients were included, all of whom had pharmacoresistant epilepsies (mean of 9.9 trials of other antiseizure treatments). Six had genetic diagnoses, four had in utero/perinatal acquired brain injury, one had a suspected focal cortical dysplasia, and five were idiopathic. Ten patients had developmental and epileptic encephalopathy with spike-wave activation in sleep, three had Lennox-Gastaut syndrome, and one each had sleep-related hyperkinetic epilepsy, self-limited epilepsy with centrotemporal spikes, and mixed generalized and multifocal epilepsy. Of the 12 patients with uncontrolled seizures at the time of sulthiame initiation, 4 had improvement in seizure frequency, including 2 who became seizure free. Eight patients had EEG data available that allowed calculation of sleep SWI; from this group, SWI decreased from 81.1% +/- 17.6% to 45.1% +/- 36.5% (p = .007). The most common adverse events reported were somnolence/drowsiness, aggression, and increased seizure frequency. Of the patients with genetic etiologies, significant positive responses were seen in patients with pathogenic variants in NDUFS1 and SATB1.

SIGNIFICANCE

These data demonstrate the therapeutic potential of sulthiame, even in patients with highly pharmacoresistant epilepsy. Improvements may be seen in both seizure frequency and sleep SWI.

Real-World Evidence of Factors Affecting Cannabidiol Exposure in Children with Drug-Resistant Developmental and Epileptic Encephalopathies

The identification of factors that affect cannabidiol (CBD) systemic exposure may aid in optimizing treatment efficacy and safety in clinical practice. In this study, we aimed to correlate CBD plasma concentrations at a steady state to demographic, clinical, and pharmacological characteristics as well as seizure frequency after the administration of a purified CBD oil solution in a real-world setting of children with drug-resistant developmental and epileptic encephalopathies (DEEs). Patients receiving oral CBD pharmaceutical products at maintenance were enrolled. Venous blood samples were drawn before the CBD morning dose, 12 h apart from the last evening dose (C0 or CBD trough concentration). A linear mixed-effect analysis was implemented to assess the correlation between C0 and clinical, laboratory, pharmacological, and lifestyle factors. Fifteen females and seven males with a median age of 12.8 years (ranging between 4.7 and 17.2) were included. The median CBD dose was 8.8 mg/kg/day (ranging between 2.6 and 22.5), and the CBD C0 median (range) was 48.2 ng/mL (3.5-366.3). The multivariate model showed a 109.6% increase in CBD C0 in patients with concomitant levothyroxine (β = 0.74 ± 0.1649, p < 0.001), 56.8% with food (β = 0.45 ± 0.1550, p < 0.01), and 116.0% after intake of a ketogenic diet (β = 0.77 ± 0.3141, p < 0.05). All patients included were responders without evidence of an association between C0 and response status. In children with DEEs, systemic concentrations of CBD may be significantly increased when co-administered with levothyroxine, food, or a ketogenic diet.

Current and emerging pharmacotherapy for the treatment of Lennox-Gastaut syndrome

INTRODUCTION

Lennox-Gastaut syndrome (LGS) is a severe childhood-onset epileptic encephalopathy, characterized by multiple seizure types, generalized slow spike-and-wave complexes in the EEG, and cognitive impairment. Seizures in LGS are typically resistant to treatment with antiseizure medications (ASMs). Tonic/atonic ('drop') seizures are of particular concern, due to their liability to cause physical injury.

AREAS COVERED

We summarize evidence for current and emerging ASMs for the treatment of seizures in LGS. The review focuses on findings from randomized, double-blind, placebo-controlled trials (RDBCTs). For ASMs for which no double-blind trials were identified, lower quality evidence was considered. Novel pharmacological agents currently undergoing investigation for the treatment of LGS are also briefly discussed.

EXPERT OPINION

Evidence from RDBCTs supports the use of cannabidiol, clobazam, felbamate, fenfluramine, lamotrigine, rufinamide, and topiramate as adjunct treatments for drop seizures. Percentage decreases in drop seizure frequency ranged from 68.3% with high-dose clobazam to 14.8% with topiramate. Valproate continues to be considered the first-line treatment, despite the absence of RDBCTs specifically in LGS. Most individuals with LGS will require treatment with multiple ASMs. Treatment decisions should be individualized and take into account adverse effects, comorbidities, general quality of life, and drug interactions, as well as individual efficacy.

Use of sulthiame as add-on therapy in children with non-self-limited focal epilepsies of childhood

PURPOSE

This retrospective study aimed to evaluate the efficacy and tolerability of sulthiame (STM) as an add-on treatment in 49 patients with non-self-limited focal epilepsies of childhood (non-SeLFE) resistant to other antiseizure medications (ASM) and/or non-pharmacological treatment.

METHODS

Patients with non-SeLFE who had failed to respond to at least five previous ASM, alone or in combination, were included in the study. All patients underwent neurological examination, brain magnetic resonance imaging repeated prolonged electroencephalography (EEG) or video-EEG studies, and neurometabolic studies. School achievements and/or performance on neuropsychological tests were also assessed. Sulthiame was added in doses ranging from 10 to 40 mg/kg/day. Efficacy was measured by comparing seizure frequency before and after initiating STM therapy.

RESULTS

Twenty-nine of 49 patients (59.1%) who received STM as add-on therapy had a greater than 50% decrease in seizures after a mean follow-up of 35 months. One patient (2%) became seizure-free. Fourteen patients (40%) had a 25-50% seizure reduction. The mean time of response was 5 months (range, 3.5 to 6 months). No differences were found either between patients with a response of more or less than 50% or between the response of the focal seizure types (motor or non-motor, with or without consciousness impairment).

CONCLUSION

In our study, STM was found to be effective and well-tolerated in children and adolescents with non-SeLFE. In the patients who responded, improvement in the EEG was seen.

Use of sulthiame as add-on therapy in children with myoclonic atonic epilepsy: A study of 35 patients

PURPOSE

The aim of this retrospective study was to evaluate efficacy and tolerability of sulthiame (STM) as add-on treatment in 35 patients with myoclonic atonic epilepsy (MAE) resistant to other antiseizure medications (ASMs) and/or non-pharmacological treatment.

METHODS

Patients were selected according to the diagnostic definition of MAE and were resistant to at least four previous to ASM, alone or in combination. Neurologic examinations, brain magnetic resonance imaging, and repeated prolonged electroencephalography (EEG) or video-EEG studies as well as neurometabolic studies were performed in all cases. Genetic studies were performed in 15 patients. Data on school achievements and/or neuropsychological evaluations were obtained over a mean follow-up of 30 months. Sulthiame was added in doses ranging from 10 to 30 mg/kg/day. Efficacy was assessed by comparing seizure frequency before and after initiating STM therapy.

RESULTS

Twenty-one of 35 patients (60%) who received STM as add-on therapy had a greater than 50% seizure decrease after a mean follow-up of 30 months. Complete seizure freedom was achieved in two patients (5.8%). The remaining 14 patients (40%) had a 25-50% seizure reduction. Adverse effects, consisting of hyperpnea and dyspnea, decreased appetite, nausea, drowsiness, headache, and irritability, were observed in 11 (31.4%). The adverse effects were mild and transient in all cases. Discontinuation of STM was not necessary.

CONCLUSION

Add-on STM led to a more than 50% seizure reduction in 21 of 35 patients with MAE with only mild or moderate adverse effects.

A fully validated HPLC-UV method for determination of sulthiame in human serum/plasma samples

Sulthiame is an old antiepileptic medicine with controversial history, whose effectiveness and safety in use have been stated in some current studies. However, there is still a need for further clinical examinations for confirmation of its usefulness and tolerability in monotherapy and add-on therapy for epilepsy of various etiologies. A fully validated RP HPLC-UV method for determination of sulthiame in serum/plasma samples using desethylatrazine as the internal standard was developed. The biological fluid was prepared for analysis by a simple precipitation method with acetonitrile. The following validation parameters of the method were determined: selectivity/specificity, linearity range (0.2-50.0 μl/ml, R²  > 0.9999), limits of detection (0.19 μl/ml) and quantification (0.58 μl/ml), precision (intra-day CV 1.06% and inter-day CV 1.25%), extraction recovery (~100%), accuracy (bias, -4.61-0.80%), carryover and ruggedness. Moreover, the stability of the medicine in plasma samples under different storage conditions was also tested. The usability of the method for clinical examinations was checked by analysis of serum samples originating from 19 patients treated with sulthiame. The proposed method is appropriate for determination of sulthiame in serum/plasma samples for drug monitoring purposes, as well as for pharmacokinetic studies.

Therapeutic approach to Lennox-Gastaut syndrome: a systematic review

Lennox-Gastaut syndrome (LGS) is a rare, age-related syndrome, characterized by multiple seizure types, mental regression, and specific EEG abnormalities. It is one of the most challenging epilepsy: treatment is rarely effective and the final prognosis remains poor, despite the availability of several antiepileptic drugs, validated through well-designed, randomized, controlled trials. However, it is reasonable to consider non-medical treatments, such as surgery, after failure of two-to-three drugs. This review has as goal to describe systematically the different therapeutic options for LGS, including, not only recognized antiepileptic drugs, but also new oral drugs, immune therapy, diet, surgery, and neurostimulation techniques.

Sulthiame add-on therapy for epilepsy

BACKGROUND

This is an updated version of the Cochrane Review previously published in the Cochrane Database of Systematic Reviews 2015, Issue 10. Epilepsy is a common neurological condition, characterised by recurrent seizures. Most people respond to conventional antiepileptic drugs, however, around 30% will continue to experience seizures, despite treatment with multiple antiepileptic drugs. Sulthiame, also known as sultiame, is a widely used antiepileptic drug in Europe and Israel. We present a summary of the evidence for the use of sulthiame as add-on therapy in epilepsy.

OBJECTIVES

To assess the efficacy and tolerability of sulthiame as add-on therapy for people with epilepsy of any aetiology compared with placebo or another antiepileptic drug.

SEARCH METHODS

For the latest update, we searched the Cochrane Register of Studies (CRS Web), which includes the Cochrane Epilepsy Group's Specialized Register and CENTRAL (17 January 2019), MEDLINE Ovid (1946 to January 16, 2019), ClinicalTrials.gov and the WHO ICTRP Search Portal (17 January 2019). We imposed no language restrictions. We contacted the manufacturers of sulthiame, and researchers in the field to seek any ongoing or unpublished studies.

SELECTION CRITERIA

Randomised controlled trials of add-on sulthiame, with any level of blinding (single, double or unblinded) in people of any age, with epilepsy of any aetiology.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, and extracted relevant data. We assessed these outcomes: (1) 50% or greater reduction in seizure frequency between baseline and end of follow-up; (2) complete cessation of seizures during follow-up; (3) mean seizure frequency; (4) time-to-treatment withdrawal; (5) adverse effects; and (6) quality of life. We used intention-to-treat for primary analyses. We presented results as risk ratios (RR) with 95% confidence intervals (CIs). However, due to the paucity of trials, we mainly conducted a narrative analysis.

MAIN RESULTS

We included one placebo-controlled trial that recruited 37 infants with newly diagnosed West syndrome. This trial was funded by DESITIN Pharma, Germany. During the study, sulthiame was given as an add-on therapy to pyridoxine. No data were reported for the outcomes: 50% or greater reduction in seizure frequency between baseline and end of follow-up; mean seizure frequency; or quality of life. For complete cessation of seizures during a nine-day follow-up period for add-on sulthiame versus placebo, the RR was 11.14 (95% CI 0.67 to 184.47; very low-certainty evidence), however, this difference was not shown to be statistically significant (P = 0.09). The number of infants experiencing one or more adverse events was not significantly different between the two treatment groups (RR 0.85, 95% CI 0.44 to 1.64; very low-certainty evidence; P = 0.63). Somnolence was more prevalent amongst infants randomised to add-on sulthiame compared to placebo, but again, the difference was not statistically significant (RR 3.40, 95% CI 0.42 to 27.59; very low-certainty evidence; P = 0.25). We were unable to conduct meaningful analysis of time-to-treatment withdrawal and adverse effects due to incomplete data.

AUTHORS' CONCLUSIONS

Sulthiame may lead to a cessation of seizures when used as an add-on therapy to pyridoxine in infants with West syndrome, however, we are very uncertain about the reliability of this finding. The included study was small and had a significant risk of bias, largely due to the lack of details regarding blinding and the incomplete reporting of outcomes. Both issues negatively impacted the certainty of the evidence. No conclusions can be drawn about the occurrence of adverse effects, change in quality of life, or mean reduction in seizure frequency. No evidence exists for the use of sulthiame as an add-on therapy in people with epilepsy outside West syndrome.Large, multi-centre randomised controlled trials are needed to inform clinical practice, if sulthiame is to be used as an add-on therapy for epilepsy.