Efficacy and Safety of Long-Term Treatment with Stiripentol in Children and Adults with Drug-Resistant Epilepsies: A Retrospective Cohort Study of 196 Patients

Use of Stiripentol in Patients with Dravet Syndrome: Common Practice Among Experts in Spain

BACKGROUND

Despite considerable evidence for the efficacy and safety of stiripentol in Dravet syndrome (DS), some aspects of stiripentol use remain challenging in clinical practice, such as dose titration and the adjustment of concomitant antiseizure medications (ASMs) to prevent potential adverse effects.

AIM

To (1) provide practical recommendations on the initiation of stiripentol treatment in patients with DS, (2) evaluate its effectiveness in the patient, and (3) guide the management of drug interactions and other aspects of treatment monitoring.

METHODS

Six Spanish neurologists (the authors) with expertise in the management of pediatric and adult patients with DS held a meeting in early 2024 to develop expert recommendations regarding the use of stiripentol in DS, based on a review of the literature and their common clinical experience.

RESULTS

According to these recommendations, stiripentol can be administered to patients with DS of any age, although its initiation and titration vary according to age group. Individualized adjustment of concomitant ASMs, such as valproic acid and clobazam or drugs specifically for DS (i.e., fenfluramine), at initiation and during stiripentol treatment, can mitigate drug interactions, thereby increasing the long-term tolerability of stiripentol treatment. In specific cases, stiripentol doses of > 50 mg/kg/day may be contemplated, and acute stiripentol administration may be considered to control refractory status epilepticus. Blood tests should be performed before starting stiripentol, at 3, 6, and 12 months after starting treatment, and then annually, except in the event of adverse effects, when additional testing may be necessary. Most adverse effects can be adequately managed by adjusting concomitant medications.

CONCLUSION

These practical recommendations may be easily adapted for use in different countries, and should increase physicians' confidence in the initiation and monitoring of stiripentol treatment, thus facilitating effective management of patients with DS and improving clinical outcomes.

Adverse events associated with Stiripentol in children aged 0-17 years: An analysis of a real-world pharmacovigilance database

OBJECTIVE

To analyze the occurrence of adverse drug events (ADEs) associated with Stiripentol (STP) use in children aged 0-17 years in real-world clinical settings.

METHODS

ADE reports on STP in children aged 0-17 years were collected from the WHO Global Case Safety Pathology Reporting Database (VigiBase), the U.S. Food and Drug Administration's Spontaneous Adverse Event Reporting System database (FAERS), and the European Medicines Agency's Pharmacovigilance database (Eudra Vigilance). Pharmacovigilance signals were identified through Reporting Odds Ratio (ROR), and Proportional Reporting Ratio (PRR).

RESULTS

In total, 31,990 ADEs were reported with "Stiripentol" as the primary suspect drug. This includes 595 ADEs from the Eudra Vigilance, 1,353 ADEs from the FAERS, and 998 ADEs from the VigiBase. All three databases indicate a higher incidence of ADEs related to STP in the categories of nervous system disorders, general disorders and administration site conditions, injury, poisoning and procedural complications, and metabolism and nutrition disorders. A higher proportion of children aged 3-11 years reported (16.48 %-32.44 %). The FAERS data shows that cerebellar atrophy (PRR of 332.94, ROR of 532.10) is the strongest signal for children aged 0-2 years, while changes in seizure presentation (PRR of 110.76, ROR of 121.06) is the strongest signal for children aged 3-11 years. For children aged 12-17 years, seizures (PRR of 46.99, ROR of 47.40) and decreased appetite(PRR of 45.51, ROR of 45.96) are the strongest signals. The Eudra Vigilance results show that boys have higher ADEs than girls for investigations, blood and lymphatic system disorders, hepatobiliary disorders, infections and infestations in children aged 0-17 years. On the other hand, girls have higher ADEs than boys for skin and subcutaneous tissue disorders, injury, poisoning and procedural complications, general disorders and administration site conditions, and gastrointestinal disorders.

CONCLUSION

In the clinical application of STP in pediatrics, it is important to examine ADEs in Nervous system disorders, Injury, poisoning and procedural complications, General disorders and administration site conditions, and Metabolism and nutrition disorders. Further studies should confirm whether there are age and gender differences in different ADEs.

Stiripentol for the treatment of refractory status epilepticus

BACKGROUND

Status epilepticus (SE) is one of the most common neurological emergencies and an acutely life-threatening condition characterized by high mortality and morbidity. Despite the well-established staged therapy of status epilepticus, especially stages 1 and 2, more than one third of patients develop (super-) refractory SE. Despite a large variety of potential treatment options for super-refractory SE, there is an unmet clinical need of potential new treatment ideas in this often desperate clinical situation. A number of studies have demonstrated the safety and efficacy of stiripentol (STP) in patients with Dravet syndrome (DS) and in children with focal epilepsy and generalized epilepsies. Some smaller series and case reports have documented the use of STP in the treatment of status epilepticus in adult patients.

METHODS

We retrospectively analyzed all patients who were admitted to the Department of Neurology at Marburg University Hospital between 2013 and 2023 with a diagnosis of (super)-refractory status epilepticus and who received additional treatment of SE with STP. All patients who received STP during the SE were included, regardless of previous medication.

RESULTS

SE ceased in 64% of 25 patients (13 female and 12 male). The mean age was 58.6 ± 21.9 years (mean ± SD). 72% had a structural epilepsy. In 20% of patients, SE was terminated by the administration of STP alone in 32% of cases, while in a further 32% of patients, the simultaneous administration of multiple anti-seizure medications (ASMs) including STP was potentially responsible for the cessation of the SE, with valproic acid (VPA), benzodiazepines and STP, being the most frequently implicated ASMs. In 12% of patients, there was at least a temporary improvement in the electroencephalogram (EEG). Stiripentol had to be discontinued in three cases due to a reduction in vigilance or hypercalcemia.

CONCLUSIONS

Stiripentol may represent a promising additional treatment option for refractory and super-refractory status epilepticus. The tolerability of this treatment has already been demonstrated in previous studies, and was also reflected in these data. Further prospective investigation in larger patient populations are necessary to ascertain the efficacy of stiripentol in SE.

TRIAL REGISTRATION

NCT06540378, retrospectively registered.

How Has the Treatment of Polish Children with Dravet Syndrome Changed? Future Perspectives

BACKGROUND

This report focuses on the treatment histories of 21 patients diagnosed with Dravet syndrome (DRVT) under the care of the Mother and Child Institute in Warsaw. This paper aims to present typical treatment schemes for patients with drug-resistant epilepsy, as well as to highlight the influence of genetic diagnosis on pharmacotherapeutic management and to present an economic analysis of hospitalization costs. This paper will also summarize the effectiveness of the latest drugs used in DRVT.

METHODS

Clinical data were collected retrospectively from available medical records. The effectiveness of anticonvulsant treatment was assessed based on epileptic seizure diaries and observations by caregivers and pediatric neurologists.

RESULTS

The study group (n = 21) consisted of patients aged 3-26 years. Orphan drugs dedicated to Dravet syndrome were introduced in all patients due to the genetic diagnosis, which significantly improved the patients' clinical conditions. The breakthrough drugs were stiripentol (in 16/21) and fenfluramine (in 3/21).

CONCLUSIONS

In recent years, molecular genetics has rapidly developed in Poland, along with a steady increase in knowledge of Dravet syndrome among the medical profession. Early and precise diagnosis provides the opportunity to target treatment with drugs dedicated to Dravet syndrome with high efficacy.

Additional Results from Two Randomized, Placebo-Controlled Trials of Stiripentol in Dravet Syndrome Highlight a Rapid Antiseizure Efficacy with Longer Seizure-Free Periods

INTRODUCTION

The efficacy of stiripentol in Dravet syndrome children was evidenced in two randomized, double-blind, placebo-controlled, phase 3 studies, namely STICLO France (October 1996-August 1998) and STICLO Italy (April 1999-October 2000), but data were not fully exploited at the time.

METHODS

This post-hoc analysis used additional information, notably collected during the open-label extension (OLE) month, or reported by caregivers in individual diaries, to evaluate new outcomes.

RESULTS

Overall, 64 patients were included (31 in the placebo group, 33 in the stiripentol group) of whom 34 (53.1%) were female. Patients' mean and median (25%; 75%) age were 9.2 years (range 3.0-20.7 years) and 8.7 years (6.0; 12.1) respectively. At the end of the double-blind treatment period, 72% of the patients in the stiripentol group had a ≥ 50% decrease in generalized tonic-clonic seizure (GTCS) frequency, versus 7% in the placebo group (P < 0.001), 56% had a profound (≥ 75%) decrease versus 3% in the placebo group (P < 0.001), and 38% were free of GTCS, but none in the placebo group (P < 0.001). The onset of stiripentol efficacy was rapid, significant from the fourth day of treatment onwards. The median longest period of consecutive days with no GTCS was 32 days in the stiripentol group compared to 8.5 days in the placebo group (P < 0.001). Further to the switch to the third month OLE, an 80.2% decrease in seizure frequency from baseline was observed in patients previously receiving placebo, while no change in efficacy was observed in those already on stiripentol. Adverse events were more frequent in the stiripentol group, with significantly more episodes of somnolence, anorexia, and weight decrease than in the placebo group.

CONCLUSION

Altogether these new analyses of the STICLO data reinforce the evidence for a remarkable efficacy of stiripentol in Dravet syndrome, with a demonstrated rapid onset of action and sustained response, as also evidenced in further post-randomized trials.

Comparative efficacy and safety of stiripentol, cannabidiol and fenfluramine as first-line add-on therapies for seizures in Dravet syndrome: A network meta-analysis

OBJECTIVES

Stiripentol, fenfluramine, and cannabidiol are licensed add-on therapies to treat seizures in Dravet Syndrome (DS). There are no direct or indirect comparisons assessing their full licensed dose regimens, across different jurisdictions, as first-line add-on therapies in DS.

METHODS

We conducted a systematic review and frequentist network meta-analysis (NMA) of randomized controlled trial (RCT) data for licensed add-on DS therapies. We compared the proportions of patients experiencing: reductions from baseline in monthly convulsive seizure frequency (MCSF) of ≥50% (clinically meaningful), ≥75% (profound), and 100% (seizure-free); serious adverse events (SAEs); discontinuations due to AEs.

RESULTS

We identified relevant data from two placebo-controlled RCTs for each drug. Stiripentol 50 mg/kg/day and fenfluramine 0.7 mg/kg/day had similar efficacy in achieving ≥50% (clinically meaningful) and ≥75% (profound) reductions from baseline in MCSF (absolute risk difference [RD] for stiripentol versus fenfluramine 1% [95% confidence interval: -20% to 22%; p = 0.93] and 6% [-15% to 27%; p = 0.59], respectively), and both were statistically superior (p < 0.05) to licensed dose regimens of cannabidiol (10 or 20 mg/kg/day, with/irrespective of clobazam) for these outcomes. Stiripentol was statistically superior in achieving seizure-free intervals compared to fenfluramine (RD = 26% [CI: 8% to 44%; p < 0.01]) and licensed dose regimens of cannabidiol. There were no significant differences in the proportions of patients experiencing SAEs. The risk of discontinuations due to AEs was lower for stiripentol, although the stiripentol trials were shorter.

SIGNIFICANCE

This NMA of RCT data indicates stiripentol, as a first-line add-on therapy in DS, is at least as effective as fenfluramine and both are more effective than cannabidiol in reducing convulsive seizures. No significant difference in the incidence of SAEs between the three add-on agents was observed, but stiripentol may have a lower risk of discontinuations due to AEs. These results may inform clinical decision-making and the continued development of guidelines for the treatment of people with DS.

PLAIN LANGUAGE SUMMARY

This study compared three drugs (stiripentol, fenfluramine, and cannabidiol) used alongside other medications for managing seizures in a severe type of epilepsy called DS. The study found that stiripentol and fenfluramine were similarly effective in reducing seizures and both were more effective than cannabidiol. Stiripentol was the best drug for stopping seizures completely based on the available clinical trial data. All three drugs had similar rates of serious side effects, but stiripentol had a lower chance of being stopped due to side effects. This information can help guide treatment choices for people with DS.

The landscape of drug resistant absence seizures in adolescents and adults: Pathophysiology, electroclinical spectrum and treatment options

The persistence of typical absence seizures (AS) in adolescence and adulthood may reduce the quality of life of patients with genetic generalized epilepsies (GGEs). The prevalence of drug resistant AS is probably underestimated in this patient population, and treatment options are relatively scarce. Similarly, atypical absence seizures in developmental and epileptic encephalopathies (DEEs) may be unrecognized, and often persist into adulthood despite improvement of more severe seizures. These two seemingly distant conditions, represented by typical AS in GGE and atypical AS in DEE, share at least partially overlapping pathophysiological and genetic mechanisms, which may be the target of drug and neurostimulation therapies. In addition, some patients with drug-resistant typical AS may present electroclinical features that lie in between the two extremes represented by these generalized forms of epilepsy.

Synthesis, Structural Elucidation, In Silico and In Vitro Studies of New Class of Methylenedioxyphenyl-Based Amide Derivatives as Potential Myeloperoxidase Inhibitors for Cardiovascular Protection

Novel methylenedioxyphenyl-based amides, especially N-(4-methoxybenzyl)-6-nitrobenzo-[1,3]-dioxole-5-carboxamide (MDC) and N-(3-acetylphenyl)-6-nitrobenzo-[1,3]-dioxole-5-carboxamide (ADC), potential cardiovascular preventive agents, are successfully synthesized, and their chemical structures are verified by 1H and 13C NMR, Fourier transform infrared (FT-IR), high-resolution mass spectrometry (HRMS), and single-crystal X-ray diffraction (SC-XRD) analyses. Data obtained from SC-XRD reveal that MDC and ADC are both monoclinic molecules with Z = 2 and 4, respectively. From density functional theory (DFT) calculations, 3.54 and 3.96 eV are the energy gaps of the optimized MDC and ADC structures, respectively. MDC and ADC exhibit an electrophilicity index value of more than 1.5 eV, suggesting that they can act as an electrophile, facilitating bond formation with biomolecules. Hirshfeld surface analysis demonstrates that more than 25% of atomic interactions in both MDC and ADC are from H···H interactions. Based on pharmacokinetic predictions, MDC and ADC exhibit drug-like properties, and molecular docking simulations revealed favorable interactions with active site pockets. Both MDC and ADC achieved higher docking scores of -7.74 and -7.79 kcal/mol, respectively, with myeloperoxidase (MPO) protein. From docking results, MPO was found to be most favorable followed by dipeptidyl peptidase-4 (DPP-4) and α-glucosidase (α-GD). Antioxidant, anti-inflammatory, and in vitro enzymatic studies of MDC and ADC indicate that MDC is more selective toward MPO and more potent than ADC. The application of MDC to inhibit myeloperoxidase could be ascertained to reduce the cardiovascular risk factor. This can be supported from the results of computational docking (based on hydrogen bonding and docking score), in vitro antioxidant and anti-inflammatory properties, and MPO enzymatic inhibition (based on the percentage of inhibition and IC50 values).

Intranasal Microemulsion as an Innovative and Promising Alternative to the Oral Route in Improving Stiripentol Brain Targeting

Stiripentol (STP) is a new-generation antiepileptic only available for oral administration. However, it is extremely unstable in acidic environments and undergoes gastrointestinal slow and incomplete dissolution. Thus, STP intranasal (IN) administration might overcome the high oral doses required to achieve therapeutic concentrations. An IN microemulsion and two variations were herein developed: the first contained a simpler external phase (FS6); the second one 0.25% of chitosan (FS6 + 0.25%CH); and the last 0.25% chitosan plus 1% albumin (FS6 + 0.25%CH + 1%BSA). STP pharmacokinetic profiles in mice were compared after IN (12.5 mg/kg), intravenous (12.5 mg/kg), and oral (100 mg/kg) administrations. All microemulsions homogeneously formed droplets with mean sizes ≤16 nm and pH between 5.5 and 6.2. Compared with oral route, IN FS6 resulted in a 37.4-fold and 110.6-fold increase of STP plasmatic and brain maximum concentrations, respectively. Eight hours after FS6 + 0.25%CH + 1%BSA administration, a second STP brain concentration peak was observed with STP targeting efficiency being 116.9% and direct-transport percentage 14.5%, suggesting that albumin may potentiate a direct STP brain transport. The relative systemic bioavailability was 947% (FS6), 893% (FS6 + 0.25%CH), and 1054% (FS6 + 0.25%CH + 1%BSA). Overall, STP IN administration using the developed microemulsions and significantly lower doses than those orally administrated might be a promising alternative to be clinically tested.