Rescue therapies for seizure emergencies: New modes of administration

Immediate Treatment of Seizure Clusters: A Conceptual Roadmap to Expedited Seizure Management

Some patients with epilepsy continue to have seizures despite daily treatment with antiseizure medications. This includes seizure clusters (also known as acute repetitive seizures), which are an increase in seizure frequency that is different from the usual seizure pattern for that patient. In the literature, the term "rescue" is used for pharmacologic treatment for seizure clusters, but clarity regarding timing or whether a caregiver or patient should wait until a moment of life-threatening urgency before administering the medication is lacking. Additionally, the concept of waiting 5 minutes to identify and initiate treatment of status epilepticus has been carried over to the treatment of seizure clusters, as well as the idea of waiting owing to safety concerns, without reevaluation in the context of the reported safety profiles for currently available as-needed therapies when administered as prescribed. Delaying treatment of seizure clusters may have negative outcomes, including injury, emergency room use, hospitalization, and progression to status epilepticus. Additionally, increased time for administration of benzodiazepines, the cornerstone therapies for seizure clusters, may lower the potency and effectiveness once administration takes place, because of physiologic changes. Thus, clarifying the importance of timing in the treatment terminology may be of benefit in the acute context. The term "immediate-use seizure medication" (ISM), meaning treatment that is administered as quickly as possible once a seizure cluster is recognized, may help to clarify the timing of as-needed treatment. This review examines the recognition and definitions of seizure clusters, the physiologic rationale for ISM for seizure clusters, and the effectiveness and safety of early treatment. Remaining knowledge gaps are also discussed. The findings of this review suggest that it may be time to revisit the terminology of "rescue", which implies waiting to administer treatment for seizure clusters, as doing so is not supported by pathophysiologic, effectiveness, or safety data.

Population-Based Analysis of 6534 Seizure Emergency Cases from Emergency Medical Services Data

INTRODUCTION

Seizures are common reasons to call an ambulance, and this study aims to analyze the burden of seizures in the prehospital setting based on incidence, hospital admission rate, and costs.

METHODS

This was a population-based, cross-sectional analysis of prehospital emergency medical services (EMS) data on suspected seizure cases from the federal state of Hesse, Germany, in 2019.

RESULTS

A total of 6534 suspected seizure cases were identified, of which most were those with a known seizure disorder. Incidence rate for epilepsy-related seizures (ES; pediatric epilepsy, first seizure [1stS], seizure with known seizure disorder [SEPI]) was 205.7 per 100,000 inhabitants and incidence rate for pediatric febrile seizures (PFS) was 36.7 per 100,000 inhabitants, corresponding to 171,275 ES and 28,500 PFS (99.3% < 18 years) cases in Germany. A prehospital EMS physician was involved in 40.0% (SEPI) to 54.4% (PFS) of suspected seizure cases. Depending on the type of seizure, 70.7% (SEPI) to 80.9% (1stS) were admitted to hospital for inpatient stay of ≥ 24 h. An additional 4% (PFS) to 16% (1stS) of cases needed immediate intervention at hospital. Prehospital EMS staff needed 8:24 min:s (SD 7:24; n = 5004) after the emergency call to arrive at the scene of the ES and 10:58 min:s (SD 27:39; n = 321) for PFS. ES and PFS cases caused estimated costs of 48.5 and 8.1 million euros for Germany in 2019, respectively, not including hospital treatment-related costs.

CONCLUSION

This study identified a high number of suspected seizure-related emergency cases and proportion of patients admitted to hospitals, as well as high associated costs in Germany.

Pharmacokinetics of Staccato® alprazolam in healthy adult participants in two phase 1 studies: An open-label smoker study and a randomized, placebo-controlled ethnobridging study

OBJECTIVE

Staccato® alprazolam is a single-use, drug-device combination delivering alprazolam to the deep lung that is being evaluated as treatment for rapid and early seizure termination. This article reports pharmacokinetic (PK) data from two phase 1 studies of Staccato alprazolam in healthy adult participants.

METHODS

The smoker study (EPK-002/NCT03516305) was an open-label, nonrandomized, single-dose, PK study in smokers and nonsmokers aged 21-50 years, administered a single inhaled dose of 1 mg Staccato alprazolam. The ethnobridging study (UP0101/NCT04782388) was a double-blind, placebo-controlled study in Japanese, Chinese, and Caucasian participants aged 18-55 years randomized 4:1 to a single inhaled dose of Staccato alprazolam 2 mg or Staccato placebo.

RESULTS

In the smoker study, 36 participants (18 smokers, 18 nonsmokers) were enrolled and received Staccato alprazolam. Following Staccato administration, alprazolam was rapidly absorbed, with a median time to peak drug plasma concentration (Tmax) of 2 min in both smokers (range = 2-30 min) and nonsmokers (range = 2-60 min). Staccato alprazolam was rapidly absorbed to a similar extent in both smokers and nonsmokers. The most commonly reported treatment-emergent adverse events (TEAEs) were somnolence and dizziness. In the ethnobridging study, 10 participants each of Japanese, Chinese, and Caucasian ethnicities were randomized 4:1 to Staccato alprazolam or Staccato placebo. Following Staccato administration, alprazolam was rapidly absorbed and distributed, with a median Tmax of 1.5-2 min in Japanese (range = 1-2 min), Chinese (range = 1-34 min), and Caucasian (range = 1-120 min) participants. Somnolence and sedation were the most commonly reported TEAEs. In both studies, there were no deaths, and no participants reported serious or severe TEAEs, or discontinued due to TEAEs.

SIGNIFICANCE

Alprazolam was rapidly absorbed, and therapeutic drug levels were achieved within 2 min postdose when administered to the lung with the Staccato device. Staccato alprazolam was generally well tolerated and displayed a safety profile consistent with that known from other alprazolam applications. No new safety signals were identified.

New GABA-Targeting Therapies for the Treatment of Seizures and Epilepsy: II. Treatments in Clinical Development

The inhibitory neurotransmitter γ-aminobutyric acid (GABA) plays an important role in the modulation of neuronal excitability, and a disruption of GABAergic transmission contributes to the pathogenesis of some seizure disorders. Although many currently available antiseizure medications do act at least in part by potentiating GABAergic transmission, there is an opportunity for further research aimed at developing more innovative GABA-targeting therapies. The present article summarises available evidence on a number of such treatments in clinical development. These can be broadly divided into three groups. The first group consists of positive allosteric modulators of GABAA receptors and includes Staccato® alprazolam (an already marketed benzodiazepine being repurposed in epilepsy as a potential rescue inhalation treatment for prolonged and repetitive seizures), the α2/3/5 subtype-selective agents darigabat and ENX-101, and the orally active neurosteroids ETX155 and LPCN 2101. A second group comprises two drugs already marketed for non-neurological indications, which could be repurposed as treatments for seizure disorders. These include bumetanide, a diuretic agent that has undergone clinical trials in phenobarbital-resistant neonatal seizures and for which the rationale for further development in this indication is under debate, and ivermectin, an antiparasitic drug currently investigated in a randomised double-blind trial in focal epilepsy. The last group comprises a series of highly innovative therapies, namely GABAergic interneurons (NRTX-001) delivered via stereotactic cerebral implantation as a treatment for mesial temporal lobe epilepsy, an antisense oligonucleotide (STK-001) aimed at upregulating NaV1.1 currents and restoring the function of GABAergic interneurons, currently tested in a trial in patients with Dravet syndrome, and an adenoviral vector-based gene therapy (ETX-101) scheduled for investigation in Dravet syndrome. Another agent, a subcutaneously administered neuroactive peptide (NRP2945) that reportedly upregulates the expression of GABAA receptor α and β subunits is being investigated, with Lennox-Gastaut syndrome and other epilepsies as proposed indications. The diversity of the current pipeline underscores a strong interest in the GABA system as a target for new treatment development in epilepsy. To date, limited clinical data are available for these investigational treatments and further studies are required to assess their potential value in addressing unmet needs in epilepsy management.

Acute seizure therapies in people with epilepsy: Fact or fiction? A U.S. Perspective

Patients with epilepsy (PWE) may experience seizure emergencies including acute repetitive seizures despite chronic treatment with daily antiseizure medications. Seizures may adversely impact routine daily activities and/or healthcare utilization and may impair the quality of life of patients with epilepsy and their caregivers. Seizures often occur at home, school, or work in a community setting. Appropriate treatment that is readily accessible for patients with seizure urgencies and emergencies is essential outside the hospital setting. When determining the best acute antiseizure therapy for PWE, clinicians need to consider all of the available rescue medications and their routes of administration including the safety and efficacy profiles. Benzodiazepines are a standard of care as a rescue therapy, yet there are several misconceptions about their use and safety. Reevaluating potential misconceptions and formulating best practices are necessary to maximize usage for each available option of acute therapy. We examine common beliefs associated with traditional use of acute seizure therapies to refute or support them based on the current level of evidence in the published literature.

Sublingual lorazepam as rescue therapy for seizure emergencies in adults

OBJECTIVE

Limited acute home treatments are available for patients with prolonged (>5 minutes) or repetitive (≥2 in 24 hours) seizures. While this early seizure treatment may reduce the need for emergency care, intermittent intranasal benzodiazepine formulations are expensive and rectal diazepam administration is often socially unacceptable. We determined whether caregivers could use sublingual lorazepam oral concentrate solution effectively as acute treatment for adults with prolonged and repetitive seizures.

METHODS

Patients prescribed sublingual lorazepam solution at the Johns Hopkins Epilepsy Center for acute seizure treatment during a 5-year period (2012-2017) were screened. We determined clinical history of seizure patterns and number of antiseizure medications (ASMs) through patient and caregiver surveys, and we verified this history in patients' medical records and charts. During a 2-year span (2017-2018), patients and caregivers were surveyed on responses to their most recent use of sublingual lorazepam solution, including seizure cessation (prolonged seizure stopping <5 minutes or ≤1 repetitive seizure), presence of sedation and adverse events within 24 hours of administration, and whether refrigeration limited use.

RESULTS

In total, 52 patients used sublingual lorazepam for treatment of acute seizures during the study period (median dose 1 mg, range 0.5 to 2 mg). Of them, 48 patients participated in treatment survey interviews. Family caregivers usually administered lorazepam (88%); 3 self-administered. Patients were surveyed on responses to their most recent use of sublingual lorazepam treatment: 66% (23/35) of patients with repetitive seizures reported no further seizure activity after administering treatment; 70% (7/10) with prolonged seizures reported seizure activity ceased within 5 minutes of treatment. Three patients treated auras and had no seizures. There were no serious adverse events during most recent use: 31% of patients developed moderate/severe sedation. Of note, 98% refrigerated lorazepam, often with coolers; 44%, however, said this limited treatment access. There was high treatment satisfaction; 79% reported that having the emergency treatment available made them feel safer.

SIGNIFICANCE

This patient survey and retrospective chart review demonstrates that home treatment with sublingual lorazepam solution may be effective for interrupting prolonged and repetitive seizures. No patients had sedation complications with home doses of 0.5 to 2 mg, and patients report high satisfaction with the treatment.

Low-dose intrapulmonary drug delivery device for studies on next-generation therapeutics in mice

Although nebulizers have been developed for delivery of small molecules in human patients, no tunable device has been purpose-built for targeted delivery of modern large molecule and temperature-sensitive therapeutics to mice. Mice are used most of all species in biomedical research and have the highest number of induced models for human-relevant diseases and transgene models. Regulatory approval of large molecule therapeutics, including antibody therapies and modified RNA highlight the need for quantifiable dose delivery in mice to model human delivery, proof-of-concept studies, efficacy, and dose-response. To this end, we developed and characterized a tunable nebulization system composed of an ultrasonic transducer equipped with a mesh nebulizer fitted with a silicone restrictor plate modification to control the nebulization rate. We have identified the elements of design that influence the most critical factors to targeted delivery to the deep lungs of BALB/c mice. By comparing an in silico model of the mouse lung with experimental data, we were able to optimize and confirm the targeted delivery of over 99% of the initial volume to the deep portions of the mouse lung. The resulting nebulizer system provides targeted lung delivery efficiency far exceeding conventional nebulizers preventing waste of expensive biologics and large molecules during proof-of-concept and pre-clinical experiments involving mice. (Word Count =207).

Economic aspects of treating seizure clusters

Seizure clusters may initiate a chain of events that have economic as well as clinical consequences. The potential economic consequences of seizure clusters must be weighed against the cost of medication to attenuate them. This is true both for individual patients and for society. Data needed for economic analyses include the chance that a cluster will progress to an adverse outcome, such as a need for emergency care, the costs of such an outcome, the cost of a rescue medication (RM), and the effectiveness of the RM. Indirect costs, such as lost employment for patients and caregivers, must also be considered. Several types of economic analyses can be used to determine costs and benefits of a medical intervention. There are studies comparing different RMs from an economic perspective, but there is little direct information on the costs of using an RM versus allowing clusters to run their course. However, the high expense of consequences of seizure clusters makes it likely that effective RMs will make economic as well as medical sense for many patients.

Updated review of rescue treatments for seizure clusters and prolonged seizures

INTRODUCTION

Although the treatment of epilepsy primarily focuses on prevention, recurrent seizures are unfortunately an ongoing reality, particularly in people with epilepsy who live with chronic refractory seizures. Rescue medications are agents which can be administered in urgent/emergent seizure episodes such as seizure clusters or prolonged seizures with the goal of terminating seizure activity, preventing morbidity, and decreasing the risk of further seizures.

AREAS COVERED

This review first discusses clinical opportunities for rescue medications, with particular attention focused on seizure clusters and prolonged seizures, including their epidemiology, risk factors, and associated morbidity. Current rescue medications, their indications, efficacy, and adverse effects are discussed. We then discuss rescue medications and formulations which are currently under development, concentrating on practical aspects relevant for clinical care.

EXPERT OPINION

Rescue medications should be considered for all people with epilepsy with ongoing seizures. Recent rescue medications including intranasal formulations provide considerable advantages. New rescue medications are being developed which may expand opportunities for effective treatment. In the future, combining rescue medications with seizure detection and seizure prediction technologies should further expand opportunities for use and should reduce the morbidity of seizures and provide increased comfort, control, and quality of life for people living with epilepsy.

Rescue therapies in epilepsy

PURPOSE OF REVIEW

The purpose of this review is to provide a succinct evaluation of the current rescue medications and action plans available to our patients with seizure clusters in the outpatient setting.

RECENT FINDINGS

The main themes of the recent findings are that rescue medications and seizure action plans (SAPs) are underutilized, particularly in the adult population. The safety and efficacy of intranasal midazolam and intranasal diazepam is comparable with rectal diazepam for the treatment of seizure clusters. Additionally, this intranasal formulation has the benefit of a more socially acceptable route of administration and ease of use.

SUMMARY

The implication of these findings is a greater variety and awareness in the rescue medications available to our patients suffering from seizure clusters.

Implications of Seizure-Cluster Treatment on Healthcare Utilization: Use of Approved Rescue Medications

PURPOSE

People with epilepsy may experience seizure clusters despite a stable regimen of antiseizure medications. Such clusters have the potential to last ≥24 hours, typically occur in the community setting, and may progress to medical emergencies, such as status epilepticus, if untreated. Thus, long-acting rescue therapy for seizure clusters is needed that can be administered by nonmedical individuals outside a hospital. Benzodiazepines are the foundation of rescue therapy for seizure clusters. The approved outpatient treatments (ie, diazepam, midazolam) have differing profiles that may affect multiple aspects of health-care utilization. The current labeling of these medications allows for a second dose if needed to control the cluster. Although no head-to-head studies directly comparing rescue treatments have been conducted, differences between studies with generally similar designs may provide context for the potential importance of second doses of rescue therapy on health-care utilization.

METHODS

For this analysis, large, long-term, open-label studies of approved seizure-cluster treatments designed for use by nonmedical caregivers were reviewed, and the percentage of seizure clusters for which a second dose was used or that were not controlled at 6, 12, and 24 hours was examined. Available data on hospitalizations were also collected.

RESULTS

The 3 identified studies meeting the inclusion criteria were for use of diazepam rectal gel, intranasal midazolam, and diazepam nasal spray. Across these studies, the use of a second dose ranged from <40% at 6 hours to <13% at 24 hours. Hospitalizations and serious treatment-emergent adverse events were reported variably across these studies.

CONCLUSION

These results demonstrate the importance of second doses of rescue therapy for seizure clusters for optimizing health-care utilization. Need for second doses should be included as one component. In turn, when second doses are needed, they have the potential to curtail emergency department use and hospitalization and to prevent further seizure clusters.

Minimum standards for inpatient long-term video-EEG monitoring: A clinical practice guideline of the international league against epilepsy and international federation of clinical neurophysiology

The objective of this clinical practice guideline is to provide recommendations on the indications and minimum standards for inpatient long-term video-electroencephalographic monitoring (LTVEM). The Working Group of the International League Against Epilepsy and the International Federation of Clinical Neurophysiology develop guidelines aligned with the Epilepsy Guidelines Task Force. We reviewed published evidence using The Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statement. We found limited high-level evidence aimed at specific aspects of diagnosis for LTVEM performed to evaluate patients with seizures and nonepileptic events (see Table S1). For classification of evidence, we used the Clinical Practice Guideline Process Manual of the American Academy of Neurology. We formulated recommendations for the indications, technical requirements, and essential practice elements of LTVEM to derive minimum standards used in the evaluation of patients with suspected epilepsy using GRADE (Grading of Recommendations, Assessment, Development, and Evaluation). Further research is needed to obtain evidence about long-term outcome effects of LTVEM and establish its clinical utility.

Minimum standards for inpatient long-term video-electroencephalographic monitoring: A clinical practice guideline of the International League Against Epilepsy and International Federation of Clinical Neurophysiology

The objective of this clinical practice guideline is to provide recommendations on the indications and minimum standards for inpatient long-term video-electroencephalographic monitoring (LTVEM). The Working Group of the International League Against Epilepsy and the International Federation of Clinical Neurophysiology develop guidelines aligned with the Epilepsy Guidelines Task Force. We reviewed published evidence using the PRISMA (Preferred Reporting Items for Systematic Review and Meta-Analysis) statement. We found limited high-level evidence aimed at specific aspects of diagnosis for LTVEM performed to evaluate patients with seizures and nonepileptic events. For classification of evidence, we used the Clinical Practice Guideline Process Manual of the American Academy of Neurology. We formulated recommendations for the indications, technical requirements, and essential practice elements of LTVEM to derive minimum standards used in the evaluation of patients with suspected epilepsy using GRADE (Grading of Recommendations Assessment, Development, and Evaluation). Further research is needed to obtain evidence about long-term outcome effects of LTVEM and to establish its clinical utility.

Rescue therapies for seizure emergencies: current and future landscape

INTRODUCTION

Seizure emergencies-status epilepticus and seizure clusters-require rapid evaluation and treatment. Several consensus-based guidelines support a prompt use of intravenous benzodiazepines as the first-line therapy in seizure emergencies. However, most seizure emergencies start outside the hospital settings. Until recently, approved prehospital rescue therapies were limited to rectal diazepam and buccal midazolam (Europe only).

METHODS

The author provides a narrative review of rescue therapies for seizure emergencies based on a comprehensive literature review (PubMed and OvidSP vendors with appropriate keywords to incorporate recent evidence) to highlight the changing landscape of seizure recue therapies.

RESULTS

A commercial version of intranasal midazolam was approved by the FDA in 2019 for 12 ≥ years old with seizure clusters. In 2020, the FDA also approved a proprietary vitamin E solution-based diazepam nose spray to abort seizure clusters in ≥ 6 years old subjects. Other than these two new options, the author discussed two previously approved therapies: rectal diazepam and buccal midazolam. The review also includes the use of intramuscular diazepam and midazolam, clonazepam wafer, sublingual and intranasal lorazepam in seizure emergencies. Besides the availability of new therapies from successful trials in controlled settings, the real-world challenges of using rescue medicines in community settings are slowly emerging.

DISCUSSION

With multiple options, a more robust and updated cost-effective analysis of different rescue medicines needs to be performed using effectiveness data from the literature and cost data from publicly available market prices. Further research is also ongoing to develop alternative non-intravenous treatment options for outpatient settings. Lastly, several other non-benzodiazepine drugs, such as allopregnanolone, propofol, and brivaracetam, are also currently under development for seizure emergencies.

A Physiologically Based Pharmacokinetic Model for Predicting Diazepam Pharmacokinetics after Intravenous, Oral, Intranasal, and Rectal Applications

Diazepam is one of the most prescribed anxiolytic and anticonvulsant that is administered through intravenous (IV), oral, intramuscular, intranasal, and rectal routes. To facilitate the clinical use of diazepam, there is a need to develop formulations that are convenient to administer in ambulatory settings. The present study aimed to develop and evaluate a physiologically based pharmacokinetic (PBPK) model for diazepam that is capable of predicting its pharmacokinetics (PK) after IV, oral, intranasal, and rectal applications using a whole-body population-based PBPK simulator, Simcyp^®. The model evaluation was carried out using visual predictive checks, observed/predicted ratios (R_obs/pred), and the average fold error (AFE) of PK parameters. The Diazepam PBPK model successfully predicted diazepam PK in an adult population after doses were administered through IV, oral, intranasal, and rectal routes, as the R_obs/pred of all PK parameters were within a two-fold error range. The developed model can be used for the development and optimization of novel diazepam dosage forms, and it can be extended to simulate drug response in situations where no clinical data are available (healthy and disease).

Final results from a Phase 3, long-term, open-label, repeat-dose safety study of diazepam nasal spray for seizure clusters in patients with epilepsy

Objective

A Phase 3 open‐label safety study (NCT02721069) evaluated long‐term safety of diazepam nasal spray (Valtoco) in patients with epilepsy and frequent seizure clusters.

Methods

Patients were 6–65 years old with diagnosed epilepsy and seizure clusters despite stable antiseizure medications. The treatment period was 12 months, with study visits at Day 30 and every 60 days thereafter, after which patients could elect to continue. Doses were based on age and weight. Seizure and treatment information was recorded in diaries. Treatment‐emergent adverse events (TEAEs), nasal irritation, and olfactory changes were recorded.

Results

Of 163 patients in the safety population, 117 (71.8%) completed the study. Duration of exposure was ≥12 months for 81.6% of patients. There was one death (sudden unexpected death in epilepsy) and one withdrawal owing to a TEAE (major depression), both considered unlikely to be related to treatment. Diazepam nasal spray was administered 4390 times for 3853 seizure clusters, with 485 clusters treated with a second dose within 24 h; 53.4% of patients had monthly average usage of one to two doses, 41.7% two to five doses, and 4.9% more than five doses. No serious TEAEs were considered to be treatment related. TEAEs possibly or probably related to treatment (n = 30) were most commonly nasal discomfort (6.1%); headache (2.5%); and dysgeusia, epistaxis, and somnolence (1.8% each). Only 13 patients (7.9%) showed nasal irritation, and there were no relevant olfactory changes. The safety profile of diazepam nasal spray was generally similar across subgroups based on age, monthly usage, concomitant benzodiazepine therapy, or seasonal allergy/rhinitis.

Significance

In this large open‐label safety study, the safety profile of diazepam nasal spray was consistent with the established profile of rectal diazepam, and the high retention rate supports effectiveness in this population. A second dose was used in only 12.6% of seizure clusters.

Seizure clusters

Acute repetitive seizures, also called seizure clusters, are common phenomena in patients with epilepsy. They are a burden on patients and their caregivers and may be very disruptive to the patients' lives. They may progress to prolonged seizures or status epilepticus if they are not aborted as soon as possible. However, their definition, recognition, and classification still suffer from a lack of consensus among healthcare professionals in the field. This review aims to shed light on various aspects of seizure clusters with particular attention to their treatments.

A review of a diazepam nasal spray for the treatment of acute seizure clusters and prolonged seizures

INTRODUCTION

Some people with epilepsy experience acute repetitive seizures (ARS), also termed seizure clusters, which have a negative impact on patient and caregiver quality of life, emotional wellbeing, daily function, and may pose risk of injury or death. In addition, these events increase healthcare utilization in emergency departments and hospitals, which might be avoided with use of an at-home rescue medication. Intranasal formulations of benzodiazepines used as rescue medications provide a means of delivering rescue medication that is socially acceptable and more easily administered than rectal drug.

AREAS COVERED

This article provides a review of intranasal diazepam covering development, pharmacokinetics, dosing, safety, adverse effects, and efficacy. The authors compare it with rectal diazepam and intranasal midazolam.

EXPERT OPINION

Intranasal rescue drugs are a valuable treatment modality for seizure clusters and prolonged seizures that are effective and well tolerated with the potential to enhance patient quality of life, reduce the incidence of seizure-related injury, and lessen the need for hospital visits. The literature does not provide evidence comparing the various rescue agents, and head-to-head comparison studies are needed. An inhaled benzodiazepine as a seizure rescue drug is currently undergoing clinical trials.

Examining the patient and caregiver experience with diazepam nasal spray for seizure clusters: Results from an exit survey of a phase 3, open-label, repeat-dose safety study

BACKGROUND

Ideal rescue treatments for acute treatment of seizure clusters should be easy to administer, so it is important to assess user perceptions of these treatments. Diazepam nasal spray is designed to have a rapid, noninvasive, and socially acceptable route of administration. Patient and caregiver (including care partner) responses to surveys from a phase 3 safety study of diazepam nasal spray are reported.

METHODS

The study enrolled patients aged 6-65 years with seizure clusters. Surveys distributed to patients and caregivers at study end, completion, or discontinuation collected data on comfort using diazepam nasal spray outside the home, timing of administration and return to their usual selves, and comfort of use compared with rectal diazepam. Safety was assessed.

RESULTS

Of 175 patients enrolled at the October 31, 2019, interim cutoff, 158 received diazepam nasal spray. Sixty-seven (42.4%) patients and 84 (53.2%) caregivers responded to the surveys (including 35 matched pairs). Most patients (78.8%, 52/66) responded that they were very comfortable doing activities outside the home with diazepam nasal spray available; 59.4% of patients returned to their usual selves within an hour of administration. Twenty-seven (40.3%) of these patients reported self-administration, 48% doing so at the first sign of a seizure. Administration of diazepam nasal spray was rated extremely or very easy by 93.8% of caregivers. Safety profile was consistent with diazepam rectal gel; no patient discontinued owing to treatment-emergent adverse events. Nasal discomfort was typically mild and transient. Among patients who had used diazepam rectal gel, most were not at all comfortable using it outside the home (86.7%) or at home (64.5%) compared with diazepam nasal spray, whereas caregivers reported that diazepam rectal gel was not at all easy to use compared with diazepam nasal spray.

CONCLUSIONS

This survey from the phase 3 safety study of diazepam nasal spray shows that patients and caregivers were satisfied with, and more comfortable using, diazepam nasal spray than rectal diazepam in public. NCT02721069.

Nose-to-brain delivery of phenytoin and its hydrophilic prodrug fosphenytoin combined in a microemulsion - formulation development and in vivo pharmacokinetics

Phenytoin is a low aqueous solubility antiepileptic drug, but its phosphate ester prodrug fosphenytoin is soluble, although less permeable. In a previous study, the intranasal administration of aqueous-based formulations of fosphenytoin led to high but delayed phenytoin bioavailability compared to the intravenous route. In this work, we hypothesized that formulating an association of the prodrug fosphenytoin and the drug phenytoin (the active and diffusible form), could result in a faster and/or more effective brain targeting. Hence, nano or microemulsions containing both active drug and prodrug were developed and characterized regarding viscosity, osmolality, pH, mean size and in vitro drug release. Then, in vivo pharmacokinetics of a selected microemulsion containing fosphenytoin and phenytoin was evaluated in mice following intranasal administration and compared with a similar microemulsion containing fosphenytoin only. Both microemulsions led to higher brain drug levels at short time points than previously developed simpler aqueous based fosphenytoin formulations, likely due to the microemulsion's permeation enhancing effect. In addition, having a small amount of phenytoin in the formulation led to an equivalent maximum brain drug concentration and an overall higher absolute bioavailability, with a prolonged drug exposure. Hence, it can be concluded that if there is a need for a fast and prolonged therapeutic effect, a drug/phosphate ester prodrug combination in a microemulsion is ideal, but if a fast effect is all that is needed, having the prodrug alone could be enough, while considering a formulation with permeation enhancing components.

Consistent safety and tolerability of Valtoco® (diazepam nasal spray) in relationship to usage frequency in patients with seizure clusters: Interim results from a phase 3, long-term, open-label, repeat-dose safety study

Objective

Need for rescue therapy differs among patients with seizure clusters. Diazepam nasal spray is approved to treat seizure clusters in patients with epilepsy ≥6 years of age. This analysis used interim data from a phase 3 safety study to assess safety profile and effectiveness of diazepam nasal spray using average number of doses/month as a proxy measurement.

Methods

This phase 3, open‐label, repeat‐dose, safety study of diazepam nasal spray enrolled patients (6‐65 years) with epilepsy and need of benzodiazepine rescue. Patients were stratified by average number of doses/month (<2, moderate frequency; 2‐5, high frequency; >5, very‐high frequency). Safety was evaluated based on treatment‐emergent adverse events (TEAEs), assessed nasal irritation, and olfaction. The proportion of treatments given as a second dose was used as an exploratory proxy for effectiveness.

Results

Of 175 enrolled patients (data cutoff, October 31, 2019), 158 received ≥1 dose of diazepam nasal spray. Frequency of use was moderate in 43.7% of patients, high in 50.6% of patients, and very high in 5.7% of patients. Patients treated 3397 seizure episodes (moderate frequency, 14.2%; high frequency, 59.9%; very high frequency, 25.8%). Nasal discomfort was the most common treatment‐related TEAE in all groups. No notable changes in nasal irritation or olfaction were observed. Second doses represented only 2.5%, 7.5%, and 17.2% of all doses in the moderate‐, high‐, and very‐high‐frequency groups, respectively. Overall retention rate was 82.9%, without an observed relationship to frequency of use.

Significance

Frequency of dosing diazepam nasal spray had little impact on the safety/tolerability profile across a range of <2 to >5 doses/month. Effectiveness was suggested for all dosing frequencies by the high proportion of seizure clusters not treated with a second dose. These results support the utility, safety profile, and effectiveness of diazepam nasal spray across frequencies of seizure cluster burden.

Overcoming the challenges of developing an intranasal diazepam rescue therapy for the treatment of seizure clusters

Seizure clusters must be treated quickly and effectively to prevent progression to prolonged seizures and status epilepticus. Rescue therapy for seizure clusters has focused on the use of benzodiazepines. Although intravenous benzodiazepine administration is the primary route in hospitals and emergency departments, seizure clusters typically occur in out‐of‐hospital settings, where a more portable product that can be easily administered by nonmedical caregivers is needed. Thus, other methods of administration have been examined, including rectal, intranasal, intramuscular, and buccal routes. Following US Food and Drug Administration (FDA) approval in 1997, rectal diazepam became the mainstay of out‐of‐hospital treatment for seizure clusters in the United States. However, social acceptability and consistent bioavailability present limitations. Intranasal formulations have potential advantages for rescue therapies, including ease of administration and faster onset of action. A midazolam nasal spray was approved by the FDA in 2019 for patients aged 12 years or older. In early 2020, the FDA approved a diazepam nasal spray for patients aged 6 years or older, which has a different formulation than the midazolam nasal product and enhances aspects of bioavailability. Benzodiazepines, including diazepam, present significant challenges in developing a suitable intranasal formulation. Diazepam nasal spray contains dodecyl maltoside (DDM) as an absorption enhancer and vitamin E to increase solubility in an easy‐to‐use portable device. In a Phase 1 study, absolute bioavailability of the diazepam nasal spray was 97% compared with intravenous diazepam. Subsequently, the nasal spray demonstrated less variability in bioavailability than rectal gel (percentage of geometric coefficient of variation of area under the curve = 42%–66% for diazepam nasal spray compared with 87%–172% for rectal gel). The diazepam nasal spray safety profile is consistent with that expected for rectal diazepam, with low rates of nasal discomfort (≤6%). To further improve the efficacy of rescue therapy, investigation of novel intranasal benzodiazepine formulations is underway.

Patterns of benzodiazepine underdosing in the Established Status Epilepticus Treatment Trial

OBJECTIVE

This study was undertaken to describe patterns of benzodiazepine use as first-line treatment of status epilepticus (SE) and test the association of benzodiazepine doses with response to second-line agents in patients enrolled in the Established Status Epilepticus Treatment Trial (ESETT).

METHODS

Patients refractory to an adequate dose of benzodiazepines for the treatment of SE were enrolled in ESETT. Choice of benzodiazepine, doses given prior to administration of second-line agent, route of administration, setting, and patient weight were characterized. These were compared with guideline-recommended dosing. Logistic regression was used to determine the association of the first dose of benzodiazepine and the cumulative benzodiazepine dose with the response to second-line agent.

RESULTS

Four hundred sixty patients were administered 1170 doses of benzodiazepines (669 lorazepam, 398 midazolam, 103 diazepam). Lorazepam was most frequently administered intravenously in the emergency department, midazolam intramuscularly or intravenously by the emergency medical services personnel, and diazepam rectally prior to ambulance arrival. The first dose of the first benzodiazepine (N = 460) was lower than guideline recommendations in 76% of midazolam administrations and 81% of lorazepam administrations. Among all administrations, >85% of midazolam and >76% of lorazepam administrations were lower than recommended. Higher first or cumulative benzodiazepine doses were not associated with better outcomes or clinical seizure cessation in response to second-line medications in these benzodiazepine-refractory seizures.

SIGNIFICANCE

Benzodiazepines as first-line treatment of SE, particularly midazolam and lorazepam, are frequently underdosed throughout the United States. This broad and generalizable cohort confirms prior single site reports that underdosing is both pervasive and difficult to remediate. (ESETT ClinicalTrials.gov identifier: NCT01960075.).

Injection of prophylactic lorazepam versus antiseizure drugs on the localization value of ictal SPECT studies and treatment-emergent adverse events: A single-center prospective study

OBJECTIVE

We aimed to examine the impact of resumption of home antiseizure drugs alone (ASD-) compared with adjunct administration of scheduled intravenous (IV) lorazepam 2 mg every 6 h (ASD+) following ictal single-photon emission computed tomography (SPECT) injection on the localization value of SPECT studies and treatment-emergent adverse events (TEAEs).

METHODS

We conducted a prospective study at Mayo Clinic inpatient epilepsy monitoring unit (EMU) between January 2018 and May 2020 in Jacksonville, Florida. The ASD- and ASD+ groups were compared for concordance of SPECT studies with the epilepsy surgical conference (ESC) consensus or intracranial electroencephalography (icEEG) findings as reference. Treatment-emergent adverse events, obtained from surveys at 24 h and one week postictal SPECT injection, were also compared between both groups.

RESULTS

Twenty-two consecutive patients with temporal (eight patients, 36%) and extratemporal (14 patients, 64%) epilepsy were included: 12 ASD+ and 10 ASD-. The two groups were well matched with regard to clinical and ictal SPECT injection characteristics including the occurrence of seizure between ictal and interictal SPECT injections. The localization value of SPECT studies was similar in the two groups. Patients in the ASD+ group reported higher rates of dizziness and excessive sedation at 24 h (p-value = 0.008). Fourteen patients (64%) underwent icEEG monitoring. For the entire cohort, the localization concordance of SPECT analysis by statistical parametric mapping (SPM) was superior to raw ictal SPECT (p-value = 0.003) and subtraction ictal SPECT coregistered to magnetic resonance imaging (MRI) (SISCOM; p-value = 0.021). Eventually, seven patients (31.8%) underwent resective brain surgery of whom four (57.1%) became seizure-free (median follow-up = 22 months).

CONCLUSIONS

Our findings suggest that resuming home ASDs without the addition of scheduled IV lorazepam following inpatient ictal SPECT injection is equally efficacious for seizure onset zone (SOZ) localization on SPECT studies, especially SPM. This approach is also associated with fewer transient TEAEs and lower financial cost with no difference in preventing seizure between ictal and interictal SPECT injections.

Intramuscular Midazolam for treatment of Status Epilepticus

INTRODUCTION

Status epilepticus (SE) is a common neurological and medical emergency. It has high mortality and morbidity rates, which typically correlate with seizure semiology and duration; therefore, prompt and proper pharmacological intervention is paramount. In a pre-hospital setting, establishing venous access can be difficult, so other routes of drug administration should be considered.

AREAS COVERED

The paper summarizes the data from the literature and provides an evaluation of the efficacy and safety of intramuscular midazolam (IM MDZ) as it pertains to the management of acute seizures and SE.

EXPERT OPINION

The cascade of events involved in the genesis and sustenance of seizures, if not promptly stopped, lead to the perpetuation of the condition and may contribute to the refractoriness of pharmacological treatment. Hence, non-venous routes for drug administration were developed to allow untrained personnel to rapidly stop seizures. Among benzodiazepines (BDZs), IM MDZ is at least as effective and safe as other intravenously administered BDZs. Moreover, thanks to IM MDZ's favorable pharmacodynamic and pharmacokinetic profile, it is a promising alternative to other non-venous drugs such as intranasal-MDZ, buccal-MDZ, and rectal-diazepam in the pre-hospital management of SE cases with motor features.

Identification of seizure clusters using free text notes in an electronic seizure diary

SIGNIFICANCE

Online seizure diaries offer a wealth of information regarding real world experience of patients living with epilepsy. Free text notes (FTN) written by patients reflect concerns and priorities of patients and provide supplemental information to structured diary data.

OBJECTIVE

This project evaluated feasibility using an automated lexical analysis to identify FTN relevant to seizure clusters (SCs).

METHODS

Data were extracted from EpiDiary™, a free electronic epilepsy diary with 42,799 unique users, generating 1,096,168 entries and 247,232 FTN. Both structured data as well as FTN were analyzed for presence of SC. A pilot study was conducted to validate an automated lexical analysis algorithm to identify SC in FTN in a sample of 98 diaries. The lexical analysis was then applied to the entire dataset. Outcomes included cluster prevalence and frequency, as well as the types of triggers commonly reported.

RESULTS

At least one FTN was found among 13,987 (32.68%) individual diaries. An automated lexical analysis algorithm identified 5797 of FTN as SC. There were 2423 unique patients with SC that were not identified by structured data alone and were identified using lexical analysis of FTN only. Seizure clusters were identified in n = 10,331 (24.1%) of diary users through both structured data and FTN. The median number of SCs days per year was 13.7, (interquartile rank (IQR): 3.2-54.7). The median number of seizures in a cluster day was 3 (IQR 2-4). The most common missed medication linked to patients with SC was levetiracetam (n = 576, 29%) followed by lamotrigine (n = 495, 24%), topiramate (n = 208, 10.5%), carbamazepine (n = 190, 9.6%), and lacosamide (n = 170, 8.6%). These percentages generally reflected prevalence of medication use in this population. The use of rescue medications was documented in 3306 of structured entries and 4305 in FTN.

CONCLUSION

This exploratory study demonstrates a novel approach applying lexical analysis to previously untapped FTN in a large electronic seizure diary database. Free text notes captured information about SC not available from the structured diary data. Diary FTN contain information of high importance to people with epilepsy, written in their own words.

A Short Review on the Intranasal Delivery of Diazepam for Treating Acute Repetitive Seizures

Benzodiazepines such as diazepam, lorazepam and midazolam remained the mainstay of treatment for acute repetitive seizures (ARS). The immediate care for ARS should often begin at home by a caregiver. This prevents the progression of ARS to prolonged seizures or status epilepticus. For a long time and despite social objections rectal diazepam gel remained only FDA-approved rescue medication. Intranasal administration of benzodiazepines is considered attractive and safe compared with rectal, buccal and sublingual routes. Intranasal delivery offers numerous advantages such as large absorptive surface area, bypass the first-pass metabolism and good patient acceptance as it is needle free and painless. Recent clinical studies have demonstrated that diazepam nasal spray (NRL-1; Valtoco^®, Neurelis Inc.,San Diego, CA, USA) showed less pharmacokinetic variability and reliable bioavailability compared with the diazepam rectal gel. Diazepam nasal spray could be considered as a suitable alternative for treating seizure emergencies outside the hospital. This review summarizes the treatment options for ARS and findings from clinical studies involving intranasal diazepam for treating seizure emergencies.

The unmet need for rapid epileptic seizure termination (REST)

Approximately 40% of epilepsy patients will continue to experience breakthrough seizures despite stable antiepileptic drug regimens. Rescue treatments have demonstrated efficacy and safety for select seizure emergencies. Outpatient administered intranasal and rectally delivered medications are regulatory approved for acute repetitive seizures (ARS), and injectable benzodiazepines are indicated for parenteral treatment of established status epilepticus. Despite these advances, no studies have been shown to abort an ongoing seizure following patient or caregiver home administration of therapy at the first clinical sign of seizure onset. Such treatment would require rapid systemic absorption without intravenous access, and evidence of seizure cessation within minutes of administration that is superior to placebo (eg, seizure self-regulation). Rapid epileptic seizure termination (REST) treatment may apply to multiple seizure emergencies beyond ARS, including focal or generalized seizures preceded by an aura, flurries of absence or myoclonic seizures, or prolonged focal and generalized seizures at high risk of progression to status epilepticus. Novel investigational drug delivery systems have demonstrated feasibility of intraictal delivery and seizure cessation by two minutes. Ongoing randomized trials of REST treatment for diverse seizure emergencies hold the potential to decrease bouts of mental and physical incapacitation in patients with drug-resistant epilepsy.

Intranasal fosphenytoin: The promise of phosphate esters in nose-to-brain delivery of poorly soluble drugs

Intranasal administration could increase both safety and efficacy of drugs acting on the central nervous system, but low solubility severely limits administration through this route. Phenytoin's prodrug, fosphenytoin, is hydrophilic and freely soluble in water, but less permeable since it is dianionic. We aimed to assess whether this phosphoester prodrug could be a suitable alternative to phenytoin in intranasal delivery. Secondly, we aimed to compare simple formulation strategies in fosphenytoin delivery. Fosphenytoin formulations containing thermosensitive and/or mucoadhesive (hydroxypropyl methylcellulose, HPMC) polymers were developed, guided by viscosity, gelling temperatures, osmolality, and in vitro drug release tests. Then, a pharmacokinetic study was performed, comparing an intravenous fosphenytoin solution, an intranasal fosphenytoin solution, and intranasal fosphenytoin mucoadhesive formulations with or without albumin. Formulations containing HPMC allowed high drug strengths, and had a relatively fast release profile, which was not changed by albumin. Intranasal administration of a formulation with HPMC and albumin prolonged drug concentration over time and led to complete or even increased absolute bioavailability. Moreover, phenytoin's blood levels did not reach the high peak obtained with intravenous administration. In conclusion, the use of phosphate ester prodrugs could be an efficient and safe strategy to increase the intranasal bioavailability of poorly soluble drugs.

Seizure clusters, rescue treatments, seizure action plans: Unmet needs and emerging formulations

PURPOSE OF REVIEW

The aim of the study was to provide an overview of the prevalence, risk factors, burden, and current and emerging pharmacologic treatments for seizure clusters in patients with epilepsy.

RECENT FINDINGS

Close to half of patients with active epilepsy experience seizure clusters, and the clinical, social, and financial burdens of seizure clusters are high. However, there is no widely accepted definition of seizure clusters; their prevalence is underappreciated, contingencies for addressing them (seizure action plans) are often lacking, and their effects are not well-studied. These issues have resulted in an insufficient number of investigations and approved medications for this condition. Novel formulations are in late-stage development to meet this unmet need.

Safety and tolerability associated with chronic intermittent use of diazepam buccal film in adult, adolescent, and pediatric patients with epilepsy

Objective

Diazepam buccal film (DBF) is in development for treatment of patients experiencing bouts of increased seizure activity. We assessed safety, tolerability, and usability of self‐ or caregiver‐administered DBF in the outpatient setting.

Methods

Patients aged 2‐65 years needing treatment with a rescue benzodiazepine at least once monthly were eligible for the study. DBF (5‐17.5 mg) was dispensed based on age and body weight. Patients/caregivers administered DBF for up to five seizure episodes per month. Adverse events (AEs) and usability assessments were recorded after the first dose, then every 3 months.

Results

Onehundred eighteen patients who used ≥1 DBF dose (adults, n = 82; adolescents, n = 19; children, n = 17) were enrolled. Eleven treatment‐related AEs (10 being mild or moderate in severity) occurred in nine (7.6%) patients over a mean of 243 days of follow‐up. No patient discontinued participation because of AEs. Mild local buccal discomfort, buccal swelling, and cheek skin sensitivity were reported by one patient each. Twenty‐two serious AEs were reported; one was treatment‐related. The three deaths reported, all unrelated to DBF, resulted from seizures or seizure with brain malignancy. Self‐administration by adults was attempted on 23.6% (188/795) of use occasions. Administration of DBF occurred under ictal or peri‐ictal conditions on 49.5% (538/1087) of use occasions, and DBF was successfully administered on a first or second attempt on 96.6% (1050/1087) of use occasions. Overall, patients received their dose of DBF on 99.2% (1078/1087) of use occasions. A second DBF dose was required within 24 hours after the first dose on 8.5% (92/1087) of use occasions.

Significance

In this observational study of chronic intermittent use, DBF was easy to administer, safe, and well tolerated in adult, adolescent, and pediatric patients with epilepsy experiencing seizure emergencies. DBF can be readily self‐administered by adults with epilepsy, as well as successfully administered by a caregiver in seizure emergencies.

Efficacy, Tolerability, and Safety of Concentrated Intranasal Midazolam Spray as Emergency Medication in Epilepsy Patients During Video-EEG Monitoring

BACKGROUND

An efficient, well tolerated, and safe emergency treatment with a rapid onset of action is needed to prevent seizure clusters and to terminate prolonged seizures and status epilepticus.

OBJECTIVES

This study aimed to examine the efficacy, tolerability, and safety of intranasal midazolam (in-MDZ) spray in clinical practice.

METHODS

In this retrospective, multicenter observational study, we evaluated all patients with peri-ictal application of in-MDZ during video-EEG monitoring at the epilepsy centers in Frankfurt and Marburg between 2 014 and 2017. For every patient, we analyzed the recurrence of any seizure or generalized tonic-clonic seizures after index seizures with and without in-MDZ administration. Treatment-emergent adverse events (TEAEs) were also evaluated.

RESULTS

In-MDZ was used in 243 patients with epilepsy (mean age 35.5 years; range 5-76 years; 46.5% female) for treatment of 459 seizures. A median dose of in-MDZ 5 mg (i.e., two puffs; range 2.5-15 mg) was administered within a median time from EEG seizure onset until in-MDZ application of 1.18 min [interquartile range (IQR) 1.27], while median time from clinical seizure onset until in-MDZ administration was 1.08 min (IQR 1.19). In-MDZ was given within 1 min after EEG seizure onset in 171 seizures. An intraindividual comparison of seizures with and without application of in-MDZ was feasible in 171 patients, demonstrating that in-MDZ reduced the occurrence of any (Cox proportional-hazard model p < 0.001) and generalized tonic-clonic seizure (Cox proportional-hazard model p = 0.0167) over a period of 24 h. The seizure-free timespan was doubled from a median of 5.0 h in controls to a median of 10.67 h after in-MDZ administration. We additionally clustered in-MDZ administrations for the 119 patients who received in-MDZ more than once, comparing them with the index cases without in-MDZ. Even when considering subsequent seizures with in-MDZ administration, a patient receiving in-MDZ is still half as likely to incur another seizure in the upcoming 24 h as compared with when the same patient does not receive in-MDZ (hazard ratio 0.50; 95% CI 0.42-0.60; p < 0.01). In-MDZ was well tolerated without major adverse events. The most common side effects were irritation of the nasal mucosa [37 cases (8.1%)], prolonged sedation [26 cases (5.7%)], and nausea and vomiting [12 cases (2.6%)]. A decline in oxygen saturation was measured after 78 seizures (17%).

CONCLUSION

We conclude that in-MDZ is a safe and efficient treatment option to prevent short-term recurrence of seizures. In-MDZ can be administered very quickly by trained staff within 1-2 min after seizure onset. No major cardiocirculatory or respiratory adverse events were observed.

Bioavailability and safety of diazepam intranasal solution compared to oral and rectal diazepam in healthy volunteers

Objective

The study assesses the bioavailability of diazepam after intranasal administration (diazepam nasal spray) in healthy volunteers. Comparative agents were diazepam rectal gel, which served as the regulatory reference product; and oral diazepam, a product with decades of clinical use. Tolerability of diazepam nasal spray was also assessed.

Methods

This was a phase 1, open‐label, randomized, single‐dose, three‐treatment, three‐period, six‐sequence crossover study in 48 healthy adult subjects that consisted of a screening period, a baseline period, and an open‐label treatment period. Interperiod intervals were at least 28 days.

Results

Forty‐eight healthy volunteer subjects were enrolled, two of whom discontinued before receiving study medication. For all routes of administration, the onset of diazepam absorption was rapid, with measurable concentrations of drug present by the first sample time point. The t_max (time to reach maximum plasma concentration) was similar for diazepam nasal spray and diazepam rectal gel, both of which were slower than oral diazepam in fasted individuals. Variability (as defined by % coefficient of variation of geometric mean) in peak plasma concentration and area under the curve_0‐∞ was lowest with oral diazepam, followed by diazepam nasal spray, with diazepam rectal gel showing the greatest variability. Overall, 131 treatment‐emergent adverse events (TEAEs) were considered mild (42 subjects, 91.3%), four TEAEs were considered moderate (four subjects, 8.3%), and no TEAEs were considered severe. The most commonly reported TEAE was somnolence at 56.5% (26/46) during diazepam nasal spray treatment, 89.1% (41/46) with the rectal diazepam gel treatment, and 82.6% (38/46) with oral diazepam treatment. No nasal irritation was observed for the majority of the subjects at any time point after administration, with no score higher than 2 (“minor bleeding that stops within 1 minute”).

Significance

Diazepam nasal spray shows predicable pharmacokinetics and represents a potential novel therapeutic approach to control bouts of increased seizure activity (cluster seizures, acute repetitive seizures).

Epilepsy Benchmarks Area III: Improved Treatment Options for Controlling Seizures and Epilepsy-Related Conditions Without Side Effects

The goals of Epilepsy Benchmark Area III involve identifying areas that are ripe for progress in terms of controlling seizures and patient symptoms in light of the most recent advances in both basic and clinical research. These goals were developed with an emphasis on potential new therapeutic strategies that will reduce seizure burden and improve quality of life for patients with epilepsy. In particular, we continue to support the proposition that a better understanding of how seizures are initiated, propagated, and terminated in different forms of epilepsy is central to enabling new approaches to treatment, including pharmacological as well as surgical and device-oriented approaches. The stubbornly high rate of treatment-resistant epilepsy—one-third of patients—emphasizes the urgent need for new therapeutic strategies, including pharmacological, procedural, device linked, and genetic. The development of new approaches can be advanced by better animal models of seizure initiation that represent salient features of human epilepsy, as well as humanized models such as induced pluripotent stem cells and organoids. The rapid advances in genetic understanding of a subset of epilepsies provide a path to new and direct patient-relevant cellular and animal models, which could catalyze conceptualization of new treatments that may be broadly applicable across multiple forms of epilepsies beyond those arising from variation in a single gene. Remarkable advances in machine learning algorithms and miniaturization of devices and increases in computational power together provide an enhanced opportunity to detect and mitigate seizures in real time via devices that interrupt electrical activity directly or administer effective pharmaceuticals. Each of these potential areas for advance will be discussed in turn.

Evaluation of Pharmacokinetics and Dose Proportionality of Diazepam After Intranasal Administration of NRL-1 to Healthy Volunteers

NRL‐1 is a novel intranasal formulation of diazepam that is being evaluated as rescue medication in patients with epilepsy who experience bouts of increased seizure activity despite stable regimens of antiepileptic drugs. This phase 1, open‐label, randomized, crossover study in healthy adult volunteers consisted of 3 single‐dose periods (5, 10, and 20 mg) followed by a 2‐dose period (2 × 10 mg) with a minimum 28‐day washout between treatments. Blood samples were taken at prespecified time points after intranasal dosing, and bioanalytic analysis of diazepam and nordiazepam was conducted using a validated liquid chromatography–tandem mass spectrometry method. Plasma pharmacokinetic parameters were summarized using descriptive statistics, and dose proportionality (peak concentration [C_max] and area under the plasma concentration–time curve [AUC_0‐∞]) was evaluated based on a power model within a 90%CI of 0.84 to 1.16. Comparisons were also conducted between single 10‐mg dose and multidose (2 × 10 mg) treatments. NRL‐1 administration resulted in rapid diazepam absorption (median time to peak concentration 1.4‐1.5 hours). Plasma concentration‐time profiles showed similar patterns of exposure that appeared to be dose dependent, with C_max of 85.6, 133.6, and 235.3 ng/mL for the 5‐, 10‐, and 20‐mg doses, respectively, although the lower 90%CI for C_max and AUC_0‐∞ exceeded dose proportionality criteria. The coefficient of variation ranged from 59% to 67% for C_max and 48% to 56% for AUC parameters. Dose‐normalized AUC_0–∞ values were comparable between the 2 × 10‐mg and single 10‐mg doses. Treatment‐emergent adverse events were consistent with those expected for diazepam, with transient somnolence the most frequent adverse event (94.4%). These results support NRL‐1 as a potential therapy for managing seizure emergencies.

Diazepam buccal film for the treatment of acute seizures

Benzodiazepines, including diazepam and midazolam, are the mainstay of treatment for seizure emergencies, including acute repetitive seizures. Nonparenteral dosage forms are used when parenteral (intravenous or intramuscular) dosing is not feasible. Currently available nonparenteral dosage forms have limitations in terms of usability, patient and caregiver acceptance, speed of action, and portability. Diazepam buccal film (DBF) is a compact, easily administered diazepam formulation. When placed onto the buccal mucosa inside the cheek, DBF adheres firmly and then rapidly dissolves, delivering diazepam transbucally and via the gastric route. In fasted healthy male volunteers, plasma levels were achieved rapidly after DBF placement in a linear dose-proportional fashion. Bioavailability in adult patients with epilepsy was not significantly different when DBF was applied interictally or periictally (within 5 min of a seizure). Diazepam buccal film was successfully placed and generally used without difficulty, even without patient cooperation immediately after a seizure. In a crossover comparative study with diazepam rectal gel (Diastat®) in adult patients with epilepsy, DBF performed equivalently to the rectal gel, but peak exposures were less variable. Diazepam buccal film is a convenient alternative for out-of-hospital treatment of seizure exacerbations. Proceedings of the 7th London-Innsbruck Colloquium on Status Epilepticus and Acute Seizures.

Intranasal Coadministration of a Diazepam Prodrug with a Converting Enzyme Results in Rapid Absorption of Diazepam in Rats

Intranasal administration is an attractive route for systemic delivery of small, lipophilic drugs because they are rapidly absorbed through the nasal mucosa into systemic circulation. However, the low solubility of lipophilic drugs often precludes aqueous nasal spray formulations. A unique approach to circumvent solubility issues involves coadministration of a hydrophilic prodrug with an exogenous converting enzyme. This strategy not only addresses poor solubility but also leads to an increase in the chemical activity gradient driving drug absorption. Herein, we report plasma and brain concentrations in rats following coadministration of a hydrophilic diazepam prodrug, avizafone, with the converting enzyme human aminopeptidase B Single doses of avizafone equivalent to diazepam at 0.500, 1.00, and 1.50 mg/kg were administered intranasally, resulting in 77.8% ± 6.0%, 112% ± 10%, and 114% ± 7% bioavailability; maximum plasma concentrations 71.5 ± 9.3, 388 ± 31, and 355 ± 187 ng/ml; and times to peak plasma concentration 5, 8, and 5 minutes for each dose level, respectively. Both diazepam and a transient intermediate were absorbed. Enzyme kinetics incorporated into a physiologically based pharmacokinetic model enabled estimation of the first-order absorption rate constants: 0.0689 ± 0.0080 minutes-1 for diazepam and 0.122 ± 0.022 minutes-1 for the intermediate. Our results demonstrate that diazepam, which is practically insoluble, can be delivered intranasally with rapid and complete absorption by coadministering avizafone with aminopeptidase B. Furthermore, even faster rates of absorption might be attained simply by increasing the enzyme concentration, potentially supplanting intravenous diazepam or lorazepam or intramuscular midazolam in the treatment of seizure emergencies.