Intranasal Delivery of Medications for the Treatment of Neurologic Conditions: A Pharmacology Update.

ABSTRACT: INTRODUCTION: Nurses have a central role in educating patients and families about treatment options and how to integrate them into action plans for neurologic conditions. In recent years, a growing number of intranasal formulations have become available as rescue therapy for neurologic conditions or symptoms including migraine, opioid overdose, and seizures. Rescue therapies do not replace maintenance medications or emergency care but are designed to enable rapid treatment of urgent or disabling conditions in community settings. Yet, discussion of rescue therapies for neurologic conditions remains limited in nursing literature. CONTENT: Intranasal formulations are specifically formulated for delivery and absorption in the nose and have several characteristics that are well suited as rescue therapies for neurologic conditions. Intranasal formulations include triptans for migraine, naloxone and nalmefene for opioid overdose, and benzodiazepines for seizure clusters in patients with epilepsy. Therapeutic attributes discussed here include ease of use in community settings by nonmedical professionals, relatively rapid onset of action, and favorable safety profile and patient experience. This information is critical for nurses to make informed decisions about rescue therapy options, incorporate these into plans of care, and educate patients, care partners, and other healthcare providers. CONCLUSION: Rescue therapies are increasingly important in the care of people with neurologic conditions. Various formulations are available and continue to evolve, offering easy and quick ways for nurses, patients, and nonmedical care partners to administer critical rescue medications. For nurses overseeing medication management, the attributes of intranasal rescue therapies should be considered in the context of providing patients with the right care at the right time.

Development of a novel dosing paradigm to model diazepam rescue therapy in preclinical seizure and epilepsy models.

Diazepam is a cornerstone immediate-use antiseizure rescue therapy that may extend the duration between seizure clusters in people living with epilepsy. However, our mechanistic understanding of intermittent rescue therapy on disease progression is limited by the lack of suitable preclinical models. Specifically, the pharmacokinetics of diazepam varies widely between humans and laboratory animals. Here, we developed a novel repeat rescue therapy dosing paradigm in rats to maintain prolonged therapeutic concentrations seen in humans. Rats received three diazepam doses separated by 1 h (0.75, 1.5, or 3 mg/kg, intraperitoneal); plasma and brains were collected at 10 min and 1, 3, or 6 h following the last dose. Plasma and brain concentrations followed a dose-dependent increase with peak concentrations following the repeat 3 mg/kg paradigm (180 ng/mL) being equivalent to plasma levels observed in human studies with diazepam nasal spray. Increased brain-to-plasma ratios in this paradigm indicate that diazepam accumulation in the brain may be long-acting at the site of action. Overall, our repeat diazepam dosing paradigm mimics drug concentrations and accumulation seen in humans, offering a preclinical tool to study the impact of benzodiazepine rescue therapy on seizure-cluster biology in rodent models of epilepsy. PLAIN LANGUAGE SUMMARY: There is more to learn about how diazepam works in the brains of people who use it only when they have two or more seizures in 24 h (this is called a seizure cluster). Ethical studies in animals can be used to learn more about medicines in the body. In this study, we showed that three doses of diazepam in rats give about the same amount of the drug as one dose for a person. We can now test rats with epilepsy to see how the drug might work in people who take it when needed for seizure clusters.

Taking a Newer, Faster, Intranasal Route: A Narrative Review of Transitioning to a Less-Invasive Rescue Treatment for Seizure Clusters.

In the US, 3 rescue treatment options are approved for patients with seizure clusters (ie, acute repetitive seizures), which are intermittent increases of seizure activity. This narrative PubMed review of these 3 treatments examines newer intranasal options that are well suited for adolescent and adult patients who may desire a transition from rectal treatment. Diazepam rectal gel is indicated for patients ≥2 years, diazepam nasal spray for those ≥6 years, and midazolam nasal spray for those ≥12 years. Approvals for diazepam rectal gel and midazolam nasal spray were based on safety and efficacy comparisons with placebo. Approval for diazepam nasal spray was based on results from long-term safety and tolerability studies in addition to its comparable bioavailability to diazepam rectal gel, while also showing less interpatient variability. The safety profiles of diazepam rectal gel and nasal spray are similar, and the medications share safety, warning, and precaution labeling. Thus, patients ≥6 years could be introduced to intranasal diazepam, allowing for continuity of familiar treatment while improving access and comfort. Intranasal midazolam also has a well-characterized safety profile. A proxy for effectiveness is the number of seizure clusters that were treated with a single dose, and these differed in separate, noncomparative studies. The safety and effectiveness of diazepam nasal spray have been examined in multiple subpopulations, whereas patient/caregiver experiences with both approved intranasal formulations have been characterized. Users may prefer nasal administration because it is noninvasive and effective, and provides social advantages, comfort, ease of use, and less variability compared with rectal gel. Nasal sprays are portable and convenient for use in the community (school, work, travel), and self-administration was reported in one study, with patients as young as 11 years old self-administering diazepam nasal spray. These newer, intranasal rescue treatments for seizure clusters provide an alternative to the rectal route.

Alternative Approaches for Addressing Acute Agitation in Schizophrenia and Bipolar Disorder.

Importance: The prompt effective treatment of acute agitation among patients with schizophrenia or bipolar disorder can alleviate distressing symptoms for the patient and decrease the risk of escalation to aggression and the potential for serious harm to the patient, health care providers, and others.Observations: A commonly used approach for the management of acute agitation has been the intramuscular administration of antipsychotic medications and/or benzodiazepines. However, US Food and Drug Administration-approved treatments with alternative routes of delivery now include inhaled loxapine powder and, more recently, dexmedetomidine sublingual film. Two formulations of intranasal olanzapine for acute agitation are in development.Conclusions and Relevance: Intranasal formulations offer the potential for favorable pharmacokinetics and onset of action combined with ease of delivery obviating the need for injections and are thus consistent with patient-centered factors such as preference and self-administration. In this review, alternative methods of medication delivery are discussed, with an emphasis on the potential for intranasal administration to treat acute agitation in adult patients with schizophrenia or bipolar disorder.Prim Care Companion CNS Disord 2024;26(1):23nr03596. Author affiliations are listed at the end of this article.

Analyses of patients who self-administered diazepam nasal spray for acute treatment of seizure clusters.

For acute treatment of seizure clusters in patients with epilepsy, intranasal administration of acute seizure therapies has been shown to provide accessibility and ease of use to care partners as well as the potential for self-administration by patients. Diazepam nasal spray (Valtoco®) was approved by the US Food and Drug Administration for acute treatment of intermittent, stereotypic episodes of frequent seizure activity (ie, seizure clusters, acute repetitive seizures) in patients with epilepsy aged ≥6 years. Self-administration consistent with the prescribing information is feasible and was reported by a subgroup of patients (n = 27 of 163) in a long-term phase 3 safety study. Data regarding self-administration among these patients with seizure clusters are examined here to explore the safety profiles and measures of effectiveness, as well as the quality of life of those who self-treated. In addition, this focused look at patients who self-administered diazepam nasal spray may offer some insights into the characteristics of patients who may be appropriate for self-administration.

Rapid Rescue Treatment with Diazepam Nasal Spray Leads to Faster Seizure Cluster Termination in Epilepsy: An Exploratory Post Hoc Cohort Analysis.

INTRODUCTION: Although prompt treatment of status epilepticus is standard of care, the effect of timing of rescue therapy administration for seizure clusters in epilepsy remains unknown. Seizure clusters are a rare but clinically important condition, and benzodiazepines are the cornerstone rescue therapy for seizure clusters in epilepsy. We characterized temporal patterns from a large dataset of treated seizure clusters in the safety study of diazepam nasal spray. METHODS: This post hoc analysis used timing data of treated seizure clusters recorded by care partners and patients in seizure diaries during a 1-year safety study. Data analysis used time from seizure start to administration of diazepam. RESULTS: From 4466 observations, 3225 had data meeting criteria for analysis. Overall, median times from seizure start to dose administration, dose administration to seizure termination, and total seizure duration were 2, 3, and 7 min, respectively. In seizure clusters treated in < 5 min (median 1.0 min), median time from dose to seizure termination was 2.0 min, and median total seizure duration was 4.0 min. Among seizure clusters treated in ≥ 5 min (median 10.0 min), median time to seizure termination was 10.0 min, and median total seizure duration was 23.0 min. Previously published safety results reported that over a mean participation of 1.5 years, 82.2% of patients had ≥ 1 treatment-emergent adverse events (TEAEs) irrespective of relationship to treatment, including 30.7% with serious TEAEs; 18.4% had TEAEs deemed at least possibly related to the study drug, none of which were serious. There were no events of cardiorespiratory depression. CONCLUSION: Echoing the importance of early use of benzodiazepines in status epilepticus, the findings from this exploratory analysis of patients with refractory epilepsy and frequent seizure clusters identify a potential benefit of early diazepam nasal spray treatment leading to faster seizure resolution within the seizure cluster. Trial Registration Information: ClinicalTrials.gov identifier NCT02721069 ( https://clinicaltrials.gov/ct2/show/NCT02721069 ).

Some people with epilepsy who take daily antiseizure drugs might still have seizures. Some of these seizures may be emergencies that can be treated with rescue medicine. For status epilepticus, rescue treatment should be given as soon as this seizure emergency is recognized. Seizure clusters are rare and might also become emergencies, but until now it had not been clear if earlier treatment would be better. Diazepam nasal spray is a rescue medicine approved to treat seizure clusters. The report used data from a study of the safety of diazepam nasal spray in people needing treatment ≥ 6 times a year. We looked at the time the seizure in a seizure cluster started to the time rescue treatment was given. We also looked at the time from taking rescue treatment to the time when that specific seizure stopped. For some seizure clusters, rescue medicine was given in < 5 min after the seizure started; on average, these seizures stopped within 2 min after rescue treatment. The total time from the start of the seizure in the seizure cluster to when it stopped was 4 min. In contrast, for seizure clusters treated after 5 min, the seizures stopped in an average of 10 min after treatment. Overall, these seizures lasted 23 min. In conclusion, this analysis found that seizures in a seizure cluster ended more quickly when diazepam nasal spray was given sooner. These findings are suggestive that select patients and caregivers should not wait to treat a seizure cluster once it has been identified.

Safety of Diazepam Nasal Spray in Pediatric Patients With Developmental Epileptic Encephalopathies: Results From a Long-term Phase 3 Safety Study.

Pediatric developmental epileptic encephalopathies are often refractory to treatment despite stable antiseizure therapy. The safety profile of diazepam nasal spray (Valtoco) as rescue therapy for seizure clusters was described in a long-term safety study. This post hoc analysis assessed safety and effectiveness within a subpopulation of patients with developmental epileptic encephalopathies. Of 163 treated patients, 64 were diagnosed with ≥1 pediatric developmental epileptic encephalopathy. Among the most common developmental epileptic encephalopathies were Rett syndrome (n = 16), Lennox-Gastaut syndrome (n = 9), and Dravet syndrome (n = 7). In the broad pediatric developmental epileptic encephalopathy group, 10.6% of seizure clusters were treated with a second dose, with similar proportions in the 3 individual encephalopathies. Across groups, treatment-emergent adverse event rates ranged from 66.7% to 100%. Only epistaxis (n = 2) was treatment-related and reported in >1 patient. In this long-term safety analysis in patients with developmental epileptic encephalopathies, diazepam nasal spray demonstrated a consistent safety profile, supporting its use in these hard-to-treat patients (ClinicalTrials.gov NCT02721069).

Use of intranasal rescue therapy for seizure clusters in students with epilepsy: Nurses' knowledge, perceptions, and practice.

School nurses play a crucial role in the prompt, appropriate response to epilepsy-related seizure emergencies among students in the school setting. Two intranasal benzodiazepine rescue therapies are now approved and offer potential benefits of being easy to use and socially acceptable. In July 2021, a survey was sent to 49,314 US school nurses to assess knowledge, perceptions, and practice with seizure rescue therapy. Responses were received from 866 (1.8% response rate). Of respondents, 45.7% had used rectal diazepam gel; 9.3%, midazolam nasal spray; and 6.0%, diazepam nasal spray. The majority (58.7%) had not delegated authority to administer rescue therapy, with state/local regulations and lack of willingness of school personnel being the most common barriers to delegation (37.7% and 20.1%, respectively). Additional training of nurses and school staff and progress on delegation policies may help optimize appropriate use of intranasal rescue therapy for seizures and enhance care of students with epilepsy in schools.

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.

Acute Abortive Therapies for Seizure Clusters in Long-Term Care.

OBJECTIVES: To describe acute seizure treatment for the long-term care setting, emphasizing rescue (acute abortive) medications for on-site management of acute unexpected seizures and seizure clusters. DESIGN: Narrative review. SETTING AND PARTICIPANTS: People with seizures in long-term care, including group residences. METHODS: PubMed was searched using keywords that pertained to rescue medications, seizure emergencies/epilepsy, seizure action plans, and long-term care. RESULTS: Seizure disorder, including epilepsy, is prevalent in long-term care residences, and rescue medications can be used for on-site treatment. Diazepam rectal gel, intranasal midazolam, and diazepam nasal spray are US Food and Drug Administration (FDA)-approved seizure-cluster rescue medications, and intravenous diazepam and lorazepam are approved for status epilepticus. Benzodiazepines differ by formulation, route of administration, absorption, and metabolism. Intranasal formulations are easy and ideal for public use and when rectal treatment is challenging (eg, wheelchair). Intranasal, intrabuccal, and rectal formulations do not require specialized training to administer and are easier for staff at all levels of training compared with intravenous treatment. Off-label rescue medications may have anecdotal support; however, potential disadvantages include variable absorption and onset of action as well as potential risks to patients and caregivers or care partners. Delivery of intravenous-administered rescue medications is delayed by the time needed to set up and deliver the medication and is subject to dosing errors. Seizure action plans that include management of acute seizures can optimize the quality and timing of treatment, which may reduce emergency service needs and prevent progression to status epilepticus. CONCLUSIONS AND IMPLICATIONS: Seizure disorder is prevalent across all ages but is increased in older adults and in those with intellectual and developmental disabilities. Prompt intervention may reduce negative outcomes associated with acute unexpected seizures and seizure clusters. Seizure action plans that include acute seizures can improve the treatment response by detailing the necessary information for staff to provide immediate treatment.

Overcoming barriers to the management of seizure clusters: ease of use and time to administration of rescue medications.

INTRODUCTION: Patients with epilepsy can experience seizure clusters (acute repetitive seizures), defined as intermittent, stereotypic episodes of frequent seizure activity that are distinct from typical seizure patterns. There are three FDA-approved rescue medications, diazepam rectal gel, midazolam nasal spray, and diazepam nasal spray, that can be administered to abort a seizure cluster in a nonmedical, community setting. Despite their effectiveness and safety, rescue medications are underutilized, and patient/caregiver experiences and perceptions of ease of use may constitute a substantial barrier to greater utilization. AREAS COVERED: The literature on rescue medications for seizure clusters is reviewed, including the effectiveness and safety, with an emphasis on ease and timing of treatment and associated outcomes. Barriers to greater utilization of rescue medication and the role of seizure action plans are discussed. EXPERT OPINION: Intranasal rescue medications are easier to use and can be administered more rapidly than other routes (rectal, intravenous). Importantly, rapid administration of intranasal rescue medications has been associated with shorter durations of seizure activity as compared with rectal/intravenous routes. Intranasal rescue medications are also easy to use and socially acceptable. These factors potentially remove or reduce barriers to use and optimize the management of seizure clusters.

Concomitant cannabidiol does not impact safety and effectiveness of diazepam nasal spray for seizure clusters: Post hoc analysis of a phase 3 safety study.

People with epilepsy may experience episodes of frequent seizure activity (seizure clusters, acute repetitive seizures), and benzodiazepines are the cornerstone of rescue treatment. Cannabidiol (CBD) can be used as an adjunctive treatment for epilepsy, and it may interact with other antiseizure drugs, such as benzodiazepines. Here, we examined the safety and effectiveness of intermittent use of diazepam nasal spray in patients with seizure clusters who also received CBD treatment. This analysis included data from patients aged 6 to 65 years enrolled in a phase 3, long-term safety study of diazepam nasal spray. Age- and weight-based dosing of diazepam nasal spray were administered during a 12-month treatment period. Concomitant CBD use was recorded, and treatment-emergent adverse events (TEAEs) were collected. Of 163 treated patients, 119 (73.0%) did not receive CBD, 23 (14.1%) received the US Food and Drug Administration-approved highly purified CBD and 21 (12.9%) received another form of CBD. On average, patients receiving highly purified CBD were younger and more likely to have epileptic encephalopathies, including Dravet syndrome or Lennox-Gastaut syndrome, than patients who received another CBD preparation or no CBD. Rates of TEAEs and serious TEAEs were greater in patients who received any form of CBD (90.9% and 45.5%, respectively) compared with no CBD (79.0% and 26.1%, respectively). However, the lowest rates of TEAEs attributed to diazepam nasal spray were reported in patients who received highly purified CBD (13.0%), and this result was maintained in those who received concomitant clobazam. Use of second doses of diazepam nasal spray, a proxy for effectiveness, was lowest in the highly purified-CBD group (8.2%) compared with the no-CBD (11.6%) and other-CBD groups (20.3%). These results suggest that CBD does not alter the safety and effectiveness of diazepam nasal spray and supports concomitant use in appropriate patients.

Significant improvements in SEIzure interVAL (time between seizure clusters) across time in patients treated with diazepam nasal spray as intermittent rescue therapy for seizure clusters.

OBJECTIVE: Intermittent rescue therapy may be used for seizure clusters, which are clinical emergencies that may persist ≥24 h and increase risk of status epilepticus, emergency room visits, and reduced quality of life for patients with epilepsy. Beyond effectiveness for aborting seizure clusters, no data exist on how intermittent rescue therapy may impact the long-term natural course of seizure clusters. This novel analysis explores SEIzure interVAL (SEIVAL; time between seizure clusters) in patients from a long-term safety study of diazepam nasal spray (Valtoco) to assess SEIVAL changes with intermittent rescue therapy across time. METHODS: Patients were aged 6-65 years. Age- and weight-based doses of diazepam nasal spray were administered during a 12-month treatment period with an optional follow-up period. SEIVAL was evaluated in patients receiving two or more doses of diazepam nasal spray using 90-day periods. RESULTS: Of 163 treated patients, 151 had one or more SEIVALs. One hundred twenty had SEIVALs in Period 1 and one or more other periods. An increase in SEIVAL was noted from Period 1 compared with all subsequent periods (p ≤ .001). A consistent cohort (n = 76) had one or more SEIVALs in each of Periods 1-4 (360 days); mean SEIVALs increased significantly (p < .01) from 12.2 days (Period 1) to 25.7 days (Period 4). Similar SEIVAL patterns occurred when repeat doses within a seizure cluster were eliminated and irrespective of age group, treatment duration, and change to concomitant medications. In adults, Quality of Life in Epilepsy scores were maintained with increased SEIVALs. SIGNIFICANCE: Across 12 months, increases in SEIVAL were demonstrated in patients using diazepam nasal spray for seizure cluster treatment in a phase 3 safety study. Increased time between seizure clusters may reflect a previously unrecognized beneficial effect of intermittent rescue therapy. These results generate a range of biological and behavioral hypotheses and warrant exploration of the impact of intermittent rescue therapy.

Quality-of-life results in adults with epilepsy using diazepam nasal spray for seizure clusters from a long-term, open-label safety study.

BACKGROUND: The impact of seizure clusters and the use of intermittent rescue therapy for clusters on the quality of life (QoL) of patients with epilepsy has not been widely studied. The present analysis assessed QoL as a secondary endpoint among adult patients with seizure clusters enrolled in a long-term, phase 3, open-label safety study (NCT02721069) of diazepam nasal spray (Valtoco®). The QoL aspect of patients in this study has not been previously published. METHODS: The 12-month safety study of diazepam nasal spray enrolled patients aged 6-65 years with seizure clusters. Adults aged ≥18 years completed the Quality of Life in Epilepsy (QOLIE)-31-P at baseline (day 0) and days 30, 150, 270, and 365. This instrument includes questions about patient health and daily activities with numeric values (1-100) assigned to responses; higher scores indicate better QoL. The QOLIE-31-P includes 7 subscales: Seizure Worry, Overall QoL, Emotional Well-Being, Energy/Fatigue, Cognitive Functioning, Medication Effects, and Social Functioning; an Overall Score is calculated as a weighted composite of the 7 subscales. Comparisons were made between subgroups of patients who had frequent (≥2) and infrequent (<2) monthly dosing of diazepam nasal spray and those whose doses were administered by the patient or a care partner. This safety study was not powered to assess efficacy endpoints; descriptive statistics were calculated across time points. In addition, safety measures, including treatment-emergent adverse events, are reported. RESULTS: Seventy-two adults who responded to the QOLIE-31-P were included in the analyses. Mean QOLIE-31-P scores were stable or increased across time points. The mean total scores increased from day 0 to day 365 by 5.2 among patients providing data for ≥1 time point (follow-up group) and 2.2 among patients providing data at all time points (QOLIE all-assessments subgroup). Subscale means for Seizure Worry and Social Functioning showed the greatest numeric increase from baseline. Mean QOLIE-31-P scores were similar in all subgroups. The safety profile in the follow-up group was similar to that seen in all study adults. CONCLUSIONS: Adults with refractory epilepsy who were treated with diazepam nasal spray for seizure clusters maintained or improved QOLIE subscale scores across the 12-month study period. Seizure Worry and Social Functioning subscale scores increased over time, suggesting improvement in these domains for this population with intractable epilepsy. Changes among subscale results suggest differences in sensitivity to the use of an intermittent treatment. The potential to improve patient function with treatment for seizure clusters warrants further study.

Cellular and behavioral effects of altered NaV1.2 sodium channel ion permeability in Scn2aK1422E mice.

Genetic variants in SCN2A, encoding the NaV1.2 voltage-gated sodium channel, are associated with a range of neurodevelopmental disorders with overlapping phenotypes. Some variants fit into a framework wherein gain-of-function missense variants that increase neuronal excitability lead to developmental and epileptic encephalopathy, while loss-of-function variants that reduce neuronal excitability lead to intellectual disability and/or autism spectrum disorder (ASD) with or without co-morbid seizures. One unique case less easily classified using this framework is the de novo missense variant SCN2A-p.K1422E, associated with infant-onset developmental delay, infantile spasms and features of ASD. Prior structure-function studies demonstrated that K1422E substitution alters ion selectivity of NaV1.2, conferring Ca2+ permeability, lowering overall conductance and conferring resistance to tetrodotoxin (TTX). Based on heterologous expression of K1422E, we developed a compartmental neuron model incorporating variant channels that predicted reductions in peak action potential (AP) speed. We generated Scn2aK1422E mice and characterized effects on neurons and neurological/neurobehavioral phenotypes. Cultured cortical neurons from heterozygous Scn2aK1422E/+ mice exhibited lower current density with a TTX-resistant component and reversal potential consistent with mixed ion permeation. Recordings from Scn2aK1442E/+ cortical slices demonstrated impaired AP initiation and larger Ca2+ transients at the axon initial segment during the rising phase of the AP, suggesting complex effects on channel function. Scn2aK1422E/+ mice exhibited rare spontaneous seizures, interictal electroencephalogram abnormalities, altered induced seizure thresholds, reduced anxiety-like behavior and alterations in olfactory-guided social behavior. Overall, Scn2aK1422E/+ mice present with phenotypes similar yet distinct from other Scn2a models, consistent with complex effects of K1422E on NaV1.2 channel function.

Lack of clinically relevant differences in safety and pharmacokinetics after second-dose administration of intranasal diazepam within 4 h for acute treatment of seizure clusters: A population analysis.

OBJECTIVE: Current diazepam nasal spray labeling requires waiting 4 h before administering a second dose. The objective of the current analyses was to examine safety and pharmacokinetic profiles of second doses of diazepam nasal spray given 0-4 h after the first dose. METHODS: Two datasets were analyzed. The first, a long-term, repeat-dose safety study of diazepam nasal spray, compared rates of treatment-emergent adverse events (TEAEs), serious TEAEs, and treatment-related TEAEs for patients receiving ≥1 second dose ≤4 h versus all second doses >4 h after the first. The second was a population pharmacokinetic analysis using data from three phase 1 studies to model drug exposure when a second dose of diazepam nasal spray was administered across multiple time points (1 min-4 h) following the first dose. RESULTS: In the repeat-dose safety study, a second dose of diazepam nasal spray was administered ≤24 h after the first to treat 485 seizure clusters in 79 patients. Rates of TEAEs were similar between patients receiving ≥1 second dose in ≤4 h (89.5%, n = 38) compared with >4-24 h only (80.5%, n = 41). The most common treatment-related TEAEs were associated with nasal discomfort, which was mild or moderate and transient. There were no reports of respiratory or cardiac depression. The pharmacokinetic simulations of second doses predicted comparable elevations of plasma diazepam concentrations with administrations across a range of intervals after the first dose (1 min-4 h). SIGNIFICANCE: These data indicate that the safety and pharmacokinetic profiles of a second dose of diazepam nasal spray administered within 4 h of the first dose are consistent with those associated with current labeling. This is potentially important for patients with seizure clusters who have a recurrent seizure within 4 h of first treatment and might benefit from immediate retreatment to reduce the risk of progression to status epilepticus.

Trends and Costs Associated With the Diagnosis and Treatment of Infantile Spasms: A 10-Year Multicenter Retrospective Review.

OBJECTIVE: Early treatment of infantile spasms (IS) may be imperative for improvement of neurodevelopmental outcomes. Existing studies have led to inconclusive recommendations with variation in treatment. Our objective was to determine the national average cost, initial diagnostic workup, treatments, and hospital length of stay for patients with IS. METHODS: This retrospective cohort study was designed to review data of patients < 2 years from 43 non-profit institutions. Data obtained included patient demographics, length of stay, admission cost, and treatments used from 2004 to 2014. Cost data were collected and adjusted to 2014 dollars, the year data were analyzed. RESULTS: A total of 6183 patients met study criteria (n = 3382, 55% male). Three-quarters of patients (n = 4684, 76%) had an electroencephalogram, 56.4% had brain imaging (n = 3487), and 17% (n = 1050) underwent a lumbar puncture. Medication for IS was initiated during inpatient hospital stay in two-thirds of all patients (n = 4139, 67%). Most patients were initiated on corticotropin (n = 2066, 33%) or topiramate (n = 1804, 29%). Average length of stay was 5.8 days with an average adjusted cost of $18,348. Over time there was an 86.6% increase in cost from an average $12,534.54 (2004) to $23,391.20 (2014), a significant change (p < 0.01). This correlated with an increase in average length of stay. CONCLUSIONS: Variability exists in diagnostic workup and pharmacotherapy initiated for IS, which may lead to differences in the cost of hospital stay. Further studies may help determine contributing factors to increased cost and improve health care utilization for IS patients.

Epilepsy and neurobehavioral abnormalities in mice with a dominant-negative KCNB1 pathogenic variant.

Developmental and epileptic encephalopathies (DEE) are a group of severe epilepsies that usually present with intractable seizures, developmental delay, and often have elevated risk for premature mortality. Numerous genes have been identified as a monogenic cause of DEE, including KCNB1. The voltage-gated potassium channel KV2.1, encoded by KCNB1, is primarily responsible for delayed rectifier potassium currents that are important regulators of excitability in electrically excitable cells, including neurons. In addition to its canonical role as a voltage-gated potassium conductance, KV2.1 also serves a highly conserved structural function organizing endoplasmic reticulum-plasma membrane junctions clustered in the soma and proximal dendrites of neurons. The de novo pathogenic variant KCNB1-p.G379R was identified in an infant with epileptic spasms, and atonic, focal and tonic-clonic seizures that were refractory to treatment with standard antiepileptic drugs. Previous work demonstrated deficits in potassium conductance, but did not assess non-conducting functions. To determine if the G379R variant affected KV2.1 clustering at endoplasmic reticulum-plasma membrane junctions, KV2.1-G379R was expressed in HEK293T cells. KV2.1-G379R expression did not induce formation of endoplasmic reticulum-plasma membrane junctions, and co-expression of KV2.1-G379R with KV2.1-wild-type lowered induction of these structures relative to KV2.1-WT alone, consistent with a dominant negative effect. To model this variant in vivo, we introduced Kcnb1G379R into mice using CRISPR/Cas9 genome editing. We characterized neuronal expression, neurological and neurobehavioral phenotypes of Kcnb1G379R/+ (Kcnb1R/+) and Kcnb1G379R/G379R (Kcnb1R/R) mice. Immunohistochemistry studies on brains from Kcnb1+/+, Kcnb1R/+ and Kcnb1R/R mice revealed genotype-dependent differences in the expression levels of KV2.1 protein, as well as associated KV2.2 and AMIGO-1 proteins. Kcnb1R/+ and Kcnb1R/R mice displayed profound hyperactivity, repetitive behaviors, impulsivity and reduced anxiety. Spontaneous seizures were observed in Kcnb1R/R mice, as well as seizures induced by exposure to novel environments and/or handling. Both Kcnb1R/+ and Kcnb1R/R mutants were more susceptible to proconvulsant-induced seizures. In addition, both Kcnb1R/+ and Kcnb1R/R mice exhibited abnormal interictal EEG activity, including isolated spike and slow waves. Overall, the Kcnb1G379R mice recapitulate many features observed in individuals with DEE due to pathogenic variants in KCNB1. This new mouse model of KCNB1-associated DEE will be valuable for improving the understanding of the underlying pathophysiology and will provide a valuable tool for the development of therapies to treat this pharmacoresistant DEE.

De novo variants of NR4A2 are associated with neurodevelopmental disorder and epilepsy.

PURPOSE: This study characterizes the clinical and genetic features of nine unrelated patients with de novo variants in the NR4A2 gene. METHODS: Variants were identified and de novo origins were confirmed through trio exome sequencing in all but one patient. Targeted RNA sequencing was performed for one variant to confirm its splicing effect. Independent discoveries were shared through GeneMatcher. RESULTS: Missense and loss-of-function variants in NR4A2 were identified in patients from eight unrelated families. One patient carried a larger deletion including adjacent genes. The cases presented with developmental delay, hypotonia (six cases), and epilepsy (six cases). De novo status was confirmed for eight patients. One variant was demonstrated to affect splicing and result in expression of abnormal transcripts likely subject to nonsense-mediated decay. CONCLUSION: Our study underscores the importance of NR4A2 as a disease gene for neurodevelopmental disorders and epilepsy. The identified variants are likely causative of the seizures and additional developmental phenotypes in these patients.