Recent advances in treatment for narcolepsy

Characterization and treatment patterns of patients treated with immediate-release sodium oxybate for narcolepsy: A propensity score-matched cohort study

BACKGROUND

Sodium oxybate (SXB) is strongly recommended for narcolepsy treatment. Comorbidities and treatment patterns of patients with narcolepsy treated vs not treated with SXB are unknown.

METHODS

An electronic health record-based search identified first-time Mayo Clinic patients with ≥ 1 narcolepsy-specific International Classification of Diseases 9th/10th Revision code and ≥ 1 diagnostic mention of narcolepsy in clinical notes (1975-2020). Common comorbidities were compared between age/sex matched cohorts with and without SXB treatment using odds ratios. Reasons for SXB therapy not being continued or taken as directed were identified using manual chart review.

RESULTS

Of the 4387 patients with narcolepsy identified, 8 % (n = 351) received SXB treatment and 92 % (n = 4036) did not. The most common comorbidities (>20 % overall population) were insomnia, fatigue, depression, hypertension, hyperlipidemia, obstructive sleep apnea, diabetes mellitus, arrhythmia, and idiopathic hypersomnia. In the cohorts of 351 matched patients, no significant differences between cohorts were observed for any comorbidity at any time point (overall, 5 years before or after diagnosis). Among patients who received SXB, 113 had clinical notes indicating discontinuation of SXB, with a reason documented for 71 (most common: lack of efficacy [n = 11]). Of the 24 recorded reasons for patients missing the second nightly SXB dose, the most frequent was the inability to wake up, with consequences noted the next day of increased symptoms.

CONCLUSIONS

No significant differences in comorbidities were observed between cohorts. Although SXB is a highly effective treatment for narcolepsy, this study highlights challenges patients face while taking twice-nightly SXB, which may result in underuse/misuse and suboptimal treatment.

Interim analysis of a post-authorization safety study of pitolisant in treating narcolepsy: A real-world European study

BACKGROUND

Narcolepsy is a chronic sleep disorder characterized mainly by excessive daytime sleepiness (EDS) and cataplexy in the case of narcolepsy type 1 (NT1). Pitolisant is a histamine 3 receptor antagonist/inverse agonist that reduces EDS and cataplexy in patients with narcolepsy.

METHODS

We performed a prospective 5-year follow-up, non-interventional study of adults with NT1 and NT2 receiving pitolisant. The primary objectives were to collect information on the long-term safety of pitolisant and analyze the utilization patterns of pitolisant. The secondary objectives were to assess clinical benefit, adherence, impact on patients' quality of life, disease burden, and patient satisfaction. We reported the results of an interim analysis after 42.6 months.

RESULTS

The population comprised 370 patients (mean age, 40 ± 15 years; 51.4 % women; NT1, 71.4 %; NT2, 28.6 %); 364 received ≥1 dose of pitolisant. Data were available for 356 patients (97.8 %). Most patients (68.4 %) had ≥1 comorbidity (obesity [BMI≥30], 31.9 %; neuropsychiatric, 31 %; and cardiovascular, 22.8 %). Forty-eight patients (13.2 %) had received no prior narcoleptic treatment, while 98 (31 %) were taking a previous therapy, which was switched to pitolisant. Treatment was combined with pitolisant in 218 (69 %) patients. Pitolisant was discontinued by 131 patients (35.4 %), mainly for safety reasons (14.3 %), lack of response (8.7 %), and patient decision (7.6 %). Overall, 355 treatment-emergent adverse events (3 serious) were reported by 156 patients (42.9 % of safety population), with 218 possibly treatment-related (61.4 %) in 109 patients (29.9 %). Improvements were observed in EDS, cataplexy, and quality of life.

CONCLUSIONS

Pitolisant was generally safe and well tolerated in patients with NT1 and NT2 and can be used in both types. Improvements were found in EDS, cataplexy, and quality of life, with good adherence and satisfaction.

Narcolepsy and rapid eye movement sleep

Since the first description of narcolepsy at the end of the 19th Century, great progress has been made. The disease is nowadays distinguished as narcolepsy type 1 and type 2. In the 1960s, the discovery of rapid eye movement sleep at sleep onset led to improved understanding of core sleep-related disease symptoms of the disease (excessive daytime sleepiness with early occurrence of rapid eye movement sleep, sleep-related hallucinations, sleep paralysis, rapid eye movement parasomnia), as possible dysregulation of rapid eye movement sleep, and cataplexy resembling an intrusion of rapid eye movement atonia during wake. The relevance of non-sleep-related symptoms, such as obesity, precocious puberty, psychiatric and cardiovascular morbidities, has subsequently been recognized. The diagnostic tools have been improved, but sleep-onset rapid eye movement periods on polysomnography and Multiple Sleep Latency Test remain key criteria. The pathogenic mechanisms of narcolepsy type 1 have been partly elucidated after the discovery of strong HLA class II association and orexin/hypocretin deficiency, a neurotransmitter that is involved in altered rapid eye movement sleep regulation. Conversely, the causes of narcolepsy type 2, where cataplexy and orexin deficiency are absent, remain unknown. Symptomatic medications to treat patients with narcolepsy have been developed, and management has been codified with guidelines, until the recent promising orexin-receptor agonists. The present review retraces the steps of the research on narcolepsy that linked the features of the disease with rapid eye movement sleep abnormality, and those that do not appear associated with rapid eye movement sleep.

Healthcare burden of narcolepsy in Japan: A retrospective analysis of health insurance claims from the Japan Medical Data Center

BACKGROUND

Narcolepsy is a chronic disorder that requires lifelong management; however, few studies have evaluated disease burden of narcolepsy. We estimated the healthcare burden of narcolepsy in Japan using data from the Japan Medical Data Center health insurance claims database.

METHODS

This was a retrospective analysis of clinical burden, healthcare resource utilization, and costs among incident narcolepsy cases and matched controls identified between January 1, 2014 and December 31, 2019.

RESULTS

Of the 1317 incident cases; 889 (with 1778 controls) were analyzed for healthcare burden, 626 (with 1252 controls) for clinical journey, and 439 (no controls) for treatment patterns. The most common baseline comorbidity was non-narcolepsy sleep disorder (41.6 % cases vs 3.0 % controls), including insomnia (28.5 % vs 2.6 %) and sleep apnea (10.8 % vs 0.3 %; both p < 0.001). The most common nonsleep disorder comorbidities were depression (35.0 % vs 2.6 %), anxiety (30.4 % vs 2.7 %), and headache/migraine (18.1 % vs 5.5 %; all p < 0.001). Compared to controls, narcolepsy cases had more prescription claims in the year following index date (82.8 % vs 9.5 %; p < 0.001), higher rates of outpatient (2291.8 vs 674.9 visits/100 person-years; p < 0.001) and inpatient claims (56.8 vs 5.1/100 person-years; p < 0.001), and longer hospital stays (mean 2.9 vs 0.5 days; p < 0.001). Similarly, median HCRU costs were higher in cases than controls (total annual healthcare costs, $2531 vs $266; community pharmacy claims, $826 vs $47 per person; and outpatient claim costs, $1053 vs $188 per person year).

CONCLUSIONS

Narcolepsy carries a substantial comorbidity burden, a high rate of medication prescribing, and high healthcare resource use in Japan.

Sodium Oxybate: Practical Considerations and Patient Perspectives

Narcolepsy is a rare, chronic sleep disorder with significant impacts on the quality of life of people affected by the disorder. People with narcolepsy (PWN) are a diverse patient population with evolving symptoms, comorbidities, and perspectives. As PWN have varying needs, clinicians should consider a more personalized approach to therapy, including active participation of PWN in their care and shared decision-making between patient and clinician to achieve optimal outcomes. In this review, we discuss the various characteristics and challenges of PWN, present illustrative clinical case scenarios of PWN, provide clinicians with a proposed framework to best address therapy for PWN, and demystify concerns with sodium oxybate.

Assessing Early Efficacy After Initiation of Once-Nightly Sodium Oxybate (ON-SXB; FT218) in Participants with Narcolepsy Type 1 or 2: A Post Hoc Analysis from the Phase 3 REST-ON Trial

BACKGROUND

Once-nightly sodium oxybate (LUMRYZ™; ON-SXB; FT218) significantly improved narcolepsy symptoms in the phase 3 REST-ON trial. The objective of this post hoc analysis was to investigate the early efficacy of ON-SXB at weeks 1 (4.5-g dose) and 2 (6-g dose).

METHODS

In REST-ON, participants (≥ 16 years) with narcolepsy type 1 or 2 were randomized 1:1 to ON-SXB (4.5 g, 1 week; 6 g, 2 weeks; 7.5 g, 5 weeks; 9 g, 5 weeks) or placebo. Protocol-prespecified efficacy assessments were conducted at weeks 3 (6-g dose), 8 (7.5-g dose), and 13 (9-g dose). A post hoc analysis was conducted to assess the early efficacy of ON-SXB, defined as efficacy at weeks 1 (4.5-g dose) and 2 (6-g dose) on Epworth Sleepiness Scale (ESS) score, visual analog scale (VAS) sleep quality, and VAS refreshing nature of sleep. Least squares mean differences (LSMD) in change from baseline to weeks 1 and 2, 95% confidence intervals (CIs), and P values were calculated using mixed-effects models for repeated measures.

RESULTS

In the modified intent-to-treat population (n = 190; ON-SXB, n = 97; placebo, n = 93), baseline ESS scores were 16.6 and 17.5, sleep quality scores were 53.8 and 55.9, and refreshing nature of sleep scores were 46.5 and 49.9 with ON-SXB and placebo, respectively. At week 1 (4.5 g), numerical improvement in ESS score (LSMD [95% CI], - 0.7 [- 1.6 to 0.2]) and significant improvements in sleep quality (3.6 [1.1-6.1]; P < 0.01) and refreshing nature of sleep (3.2 [0.5-5.9]; P < 0.05) were observed with ON-SXB versus placebo. At week 2 (6 g), significant improvements with ON-SXB versus placebo were observed for ESS score (- 1.3 [- 2.4 to - 0.2]; P < 0.02), sleep quality (7.0 [3.8-10.1]; P < 0.001), and refreshing nature of sleep (5.8 [2.3-9.4]; P = 0.001).

CONCLUSIONS

ON-SXB improved daytime sleepiness, sleep quality, and refreshing nature of sleep, with observable benefits beginning in the first week of treatment. These data may help clinicians set expectations with patients.

CLINICAL TRIAL ID

NCT02720744.

Epidemiology, patient characteristics, and treatment patterns of patients with narcolepsy in Sweden: a non-interventional study using secondary data

Study Objectives

To estimate the prevalence and incidence and evaluate the treatment patterns of patients diagnosed with narcolepsy in specialist care in Sweden.

Methods

This non-interventional retrospective longitudinal study used Swedish register data from 2010 to 2020 and included patients diagnosed with narcolepsy (either type 1 or type 2), recorded in specialist outpatient and inpatient care from January 2015 to December 2019. All patients received an index date corresponding to the date of the first narcolepsy diagnosis.

Results

The prevalence and incidence of narcolepsy were 14.7/100 000 and 0.9/100 000 individuals, respectively, with a greater proportion of females than males. The study included 1846 prevalent narcolepsy patients of either type, of which 466 were incident. The majority of prevalent patients (87.9%) were prescribed narcolepsy-related treatment at index with stimulants being the most common treatment. Both in the years before and after index, the most used medication by prevalent patients was stimulants (42.4% and 54.8%, respectively). Among incident patients, stimulants were the most common drug in the year after index (57.0%). Treatment switching following index was frequent and a large share of incident patients who started on modafinil were switched to stimulants.

Conclusions

The prevalence of narcolepsy was lower than previously reported and was higher in females than in males; incidence was comparable throughout the study period. At index, not all patients used narcolepsy-related medications, potentially indicating a hesitance towards treatment and/or a need for faster initiation of treatment following index. Many patients were switched from the treatment they first initiated after diagnosis, which might be due to a lack of efficacy and/or unacceptable side effects.

Bibliometric and visual study of narcolepsy from 2000 to 2023

BACKGROUND

More studies explored the prevalence, causes, associated conditions, and therapeutic strategies of narcolepsy. With an increasing focus on understanding narcolepsy's prevalence, associated conditions, and therapeutic strategies, there's a notable absence of bibliometric analyses summarizing trends in research and identifying emerging areas of focus within this field.

AIM

To conduct a bibliometric analysis to investigate the current status and frontiers of narcolepsy.

METHODS

The documents related to narcolepsy are obtained from the Web of Science Core Collection database (WoSCC) from January 1, 2000, to December 31, 2023, and VOS viewer 1.6.16, and the WoSCC's literature analysis wire were used to conduct the bibliometric analysis.

RESULTS

A total of 4672 publications related to narcolepsy were included, and 16182 authors across 4397 institutions and 96 countries/regions contributed to these documents in 1131 different journals. The most productive author, institution, country and journal were Yves Dauvilliers, Stanford University, United States, and Sleep Medicine, respectively. The first high-cited document was published in Nature in 2005 by Saper et al, and this research underscores the role of certain neurons in ensuring the stability of sleep-wake transitions, offering insights into narcolepsy's pathophysiology.

CONCLUSION

In conclusion, the main research hotspots and frontiers in the field of narcolepsy are the diagnosis of narcolepsy, pathological mechanism of narcolepsy and the treatment of narcolepsy. More studies are needed to explore effective strategies for the diagnosis and treatment of narcolepsy.

Samelisant (SUVN-G3031), a histamine 3 receptor inverse agonist: Results from the phase 2 double-blind randomized placebo-controlled study for the treatment of excessive daytime sleepiness in adult patients with narcolepsy

Narcolepsy is a rare, chronic neurological disorder characterized by a dysregulated sleep-wake cycle, with core clinical features including excessive daytime sleepiness (EDS), cataplexy, hypnopompic/hypnagogic hallucinations, and sleep paralysis. Several treatment options are available for the symptomatic management of narcolepsy, but they have limitations. Comorbidities of narcolepsy further limit the treatment choices. Blocking of histamine 3 (H3) receptors has been demonstrated to be a viable approach for the management of symptoms of narcolepsy. Samelisant (SUVN-G3031) is a new H3 receptor inverse agonist. The efficacy, safety, tolerability, and pharmacokinetics of Samelisant in narcolepsy patients were evaluated in a phase 2, double-blind, placebo-controlled study (ClinicalTrials.gov identifier: NCT04072380). Patients diagnosed with narcolepsy according to the International Classification of Sleep Disorders criteria and having an Epworth Sleepiness Scale (ESS) score of ≥12 and a mean Maintenance of Wakefulness Test (MWT) time of <12 min across the 4 sessions at baseline were enrolled. The total study duration was up to 7 weeks, which included a screening period of 4 weeks, a treatment period of 2 weeks, and a safety follow-up 1 week after the last study drug administration. The primary efficacy measure was the change in total ESS score compared to placebo. Secondary and exploratory assessments included the Clinical Global Impression of Severity, MWT, Clinical Global Impression of Change, Patient Global Impression of Change and cataplexy rate. Safety assessments included monitoring adverse events (AEs) and laboratory assessments. Of the 426 patients screened, 190 were randomized. The safety and intention-to-treat population included 188 and 164 patients, respectively. A statistically significant treatment effect of Samelisant was observed on the primary endpoint, indicating improvements in EDS. The treatment's impact on EDS was also evident on the other patients' and clinicians' perspectives scales. The AEs reported in ≥5 % patients in any treatment groups were insomnia, abnormal dreams, nausea, and hot flush. Global phase 3 studies and long-term safety and efficacy assessments of Samelisant are planned to reaffirm the current findings.

Treatment of Narcolepsy Type 1 With Orexin: A Systematic Review

Narcolepsy is a rare, chronic neurological disorder characterized by excessive daytime sleepiness (EDS). Narcolepsy type 1 is probably caused by an autoimmune-mediated loss of orexin-producing neurons. Type 2 patients retain the physiological functioning of orexigenic neurons. The basis for treating narcolepsy type 1 with orexin-A is that if narcolepsy develops because of a loss of orexigenic neurons, then administering orexin should be able to eliminate, reduce, or prevent the impact of this loss. The aim of this review was to capture and analyze studies to elucidate the efficacy of orexin-A in the treatment of narcolepsy type 1 in humans. The search strategy included the following descriptors: "narcolepsy," "orexin," and "treatment," with filters for randomized clinical trials (RCT) and human studies. A total of 70 publications were retrieved from the databases. Duplicate records were removed before screening (n = 13), and 54 were then excluded for the following reasons: off-topic (n = 18), reviews (n = 14), use of a different intervention other than orexin (n = 14), non-human studies (n = 4), out-of-population selection criteria (n = 2), and case report (n = 2). Thus, the studies included in the review were three. Treatment of narcolepsy with orexin decreases the number of wake-REM (rapid eye movement) transitions and total time of REM sleep, although it does not increase wake time. The failure of orexin to alleviate daytime sleepiness suggests that orexin deficiency is not the only factor involved in the pathophysiology of type I narcolepsy.

REM sleep in narcolepsy

Narcolepsy is mainly associated with excessive daytime sleepiness, but the characteristic feature is abnormal rapid eye movement (REM) sleep phenomena. REM sleep disturbances can manifest as cataplexy (in narcolepsy type 1), sleep paralysis, sleep-related hallucinations, REM sleep behavior disorder, abnormal dreams, polysomnographic evidence of REM sleep disruption with sleep-onset REM periods, and fragmented REM sleep. Characterization of REM sleep and related symptoms facilitates the differentiation of narcolepsy from other central hypersomnolence disorders and aids in distinguishing between narcolepsy types 1 and 2. A circuit comprising regions within the brainstem, forebrain, and hypothalamus is involved in generating and regulating REM sleep, which is influenced by changes in monoamines, acetylcholine, and neuropeptides. REM sleep is associated with brainstem functions, including autonomic control, and REM sleep disturbances may be associated with increased cardiovascular risk. Medications used to treat narcolepsy (and REM-related symptoms of narcolepsy) include stimulants/wake-promoting agents, pitolisant, oxybates, and antidepressants; hypocretin agonists are a potential new class of therapeutics. The role of REM sleep disturbances in narcolepsy remains an area of active research in pathophysiology, symptom management, and treatment. This review summarizes the current understanding of the role of REM sleep and its dysfunction in narcolepsy.

Eurycoma longifolia (Tongkat Ali) supplementation enhances sleep and wake consolidation in wild-type, but not in narcoleptic mice

Tongkat Ali (TA), also known as Eurycoma longifolia, has been used as a traditional herbal medicine for anti-aging, evidenced by clinical trials presenting the beneficial effects on energy, fatigue, and mood disturbance. We have recently shown that TA supplementation dose-dependently enhances the rest-activity pattern in C57BL/6 mice. Since destabilization of wakefulness and sleep is one of the typical symptoms of not only the elderly but also narcolepsy, we performed sleep analysis with and without dietary TA extract supplementation in middle-aged (10-12 months old) wild-type (WT) and narcoleptic DTA mice. We found that TA supplementation enhanced diurnal rhythms of locomotion and temperature in a time-of-day-dependent manner in WT mice but attenuated in DTA mice. In WT mice, TA supplementation consolidated wakefulness with a long bout duration and led to less entries into the sleep state during the active period, while it consolidated NREM sleep with long bout duration during the resting period. Neither disturbed sleep and wake cycles nor cataplexy was sufficiently improved in DTA mice. EEG spectral analysis revealed that TA supplementation enhanced slow wave activity (SWA) at both delta and low delta frequencies (0.5-4.0 and 0.5-2.0 Hz) during the light period, suggesting TA extract may induce vigilance during the active period, which then elicits a rebound effect during the resting period. Interestingly, DTA mice also slightly, but significantly, increased SWA at low frequencies during the light period. Taken together, our results suggest that TA supplementation enhances the Yin-Yang balance of sleep, temperature, and locomotion in WT mice, while its efficacy is limited in narcoleptic mice.

Sex-dependent effects of monomeric α-synuclein on calcium and cell death of lateral hypothalamic mouse neurons are altered by orexin

Parkinson's Disease (PD) patients experience sleeping disorders in addition to the disease-defining symptomology of movement dysfunctions. The prevalence of PD is sex-based and presence of sleeping disorders in PD also shows sex bias with a stronger phenotype in males. In addition to loss of dopamine-containing neurons in the striatum, arousal-related, orexin-containing neurons in the lateral hypothalamus (LH) are lost in PD, which could contribute to state-related disorders. As orexin has been shown to be involved in sleeping disorders and to have neuroprotective effects, we asked whether orexin could protect sleep-related LH neurons from damage putatively from the protein α-synuclein (α-syn), which is found at high levels in the PD brain and that we have shown is associated with putatively excitotoxic rises in intracellular calcium in brainstem sleep-controlling nuclei, especially in males. Accordingly, we monitored intracellular calcium transients induced by α-syn and whether concurrent exposure to orexin affected those transients in LH cells of the mouse brain slice using calcium imaging. Further, we used an assay of cell death to determine whether LH cell viability was influenced when α-syn and orexin were co-applied when compared to exposure to α-syn alone. We found that excitatory calcium events induced by α-syn were reduced in amplitude and frequency when orexin was co-applied, and when data were evaluated by sex, this effect was found to be greater in females. In addition, α-syn exposure was associated with cell death that was higher in males, and interestingly, reduced cell death was noted when orexin was present, which did not show a sex bias. We interpret our findings to indicate that orexin is protective to α-syn-mediated damage to hypothalamic neurons, and the actions of orexin on α-syn-induced cellular effects differ between sexes, which could underlie sex-based differences in sleeping disorders in PD.

Exploring the Literature on Narcolepsy: Insights into the Sleep Disorder That Strikes during the Day

Narcolepsy is a chronic sleep disorder that disrupts the regulation of a person's sleep-wake cycle, leading to significant challenges in daily functioning. It is characterized by excessive daytime sleepiness, sudden muscle weakness (cataplexy), sleep paralysis, and vivid hypnagogic hallucinations. A literature search was conducted in different databases to identify relevant studies on various aspects of narcolepsy. The main search terms included "narcolepsy", "excessive daytime sleepiness", "cataplexy", and related terms. The search was limited to studies published until May 2023. This literature review aims to provide an overview of narcolepsy, encompassing its causes, diagnosis, treatment options, impact on individuals' lives, prevalence, and recommendations for future research. The review reveals several important findings regarding narcolepsy: 1. the classification of narcolepsy-type 1 narcolepsy, previously known as narcolepsy with cataplexy, and type 2 narcolepsy, also referred to as narcolepsy without cataplexy; 2. the genetic component of narcolepsy and the complex nature of the disorder, which is characterized by excessive daytime sleepiness, disrupted sleep patterns, and potential impacts on daily life activities and social functioning; and 3. the important implications for clinical practice in the management of narcolepsy. Healthcare professionals should be aware of the different types of narcolepsies and their associated symptoms, as this can aid in accurate diagnosis and treatment planning. The review underscores the need for a multidisciplinary approach to narcolepsy management, involving specialists in sleep medicine, neurology, psychiatry, and psychology. Clinicians should consider the impact of narcolepsy on a person's daily life, including their ability to work, study, and participate in social activities, and provide appropriate support and interventions. There are several gaps in knowledge regarding narcolepsy. Future research should focus on further elucidating the genetic causes and epigenetic mechanisms of narcolepsy and exploring potential biomarkers for early detection and diagnosis. Long-term studies assessing the effectiveness of different treatment approaches, including pharmacological interventions and behavioral therapies, are needed. Additionally, there is a need for research on strategies to improve the overall well-being and quality of life of individuals living with narcolepsy, including the development of tailored support programs and interventions.

Narcolepsies, update in 2023

Narcolepsy type 1 (NT1) and type 2 (NT2), also known as narcolepsy with and without cataplexy, are sleep disorders that benefited from major scientific advances over the last two decades. NT1 is caused by the loss of hypothalamic neurons producing orexin/hypocretin, a neurotransmitter regulating sleep and wake, which can be measured in the cerebrospinal fluid (CSF). A low CSF level of hypocretin-1/orexin-A is a highly specific and sensitive biomarker, sufficient to diagnose NT1. Orexin-deficiency is responsible for the main NT1 symptoms: sleepiness, cataplexy, disrupted nocturnal sleep, sleep-related hallucinations, and sleep paralysis. In the absence of a lumbar puncture, the diagnosis is based on neurophysiological tests (nocturnal and diurnal) and the presence of the pathognomonic symptom cataplexy. In the revised version of the International Classification of sleep Disorders, 3rd edition (ICSD-3-TR), a sleep onset rapid eye movement sleep (REM) period (SOREMP) (i.e. rapid occurrence of REM sleep) during the previous polysomnography may replace the diurnal multiple sleep latency test, when clear-cut cataplexy is present. A nocturnal SOREMP is very specific but not sensitive enough, and the diagnosis of cataplexy is usually based on clinical interview. It is thus of crucial importance to define typical versus atypical cataplectic attacks, and a list of clinical features and related degrees of certainty is proposed in this paper (expert opinion). The time frame of at least three months of evolution of sleepiness to diagnose NT1 was removed in the ICSD-3-TR, when clear-cut cataplexy or orexin-deficiency are established. However, it was kept for NT2 diagnosis, a less well-characterized disorder with unknown clinical course and absence of biolo biomarkers; sleep deprivation, shift working and substances intake being major differential diagnoses. Treatment of narcolepsy is nowadays only symptomatic, but the upcoming arrival of non-peptide orexin receptor-2 agonists should be a revolution in the management of these rare sleep diseases.

Evaluation of the efficacy of the hypocretin/orexin receptor agonists TAK-925 and ARN-776 in narcoleptic orexin/tTA; TetO-DTA mice

The sleep disorder narcolepsy, a hypocretin deficiency disorder thought to be due to degeneration of hypothalamic hypocretin/orexin neurons, is currently treated symptomatically. We evaluated the efficacy of two small molecule hypocretin/orexin receptor-2 (HCRTR2) agonists in narcoleptic male orexin/tTA; TetO-DTA mice. TAK-925 (1-10 mg/kg, s.c.) and ARN-776 (1-10 mg/kg, i.p.) were injected 15 min before dark onset in a repeated measures design. EEG, EMG, subcutaneous temperature (Tsc ) and activity were recorded by telemetry; recordings for the first 6 h of the dark period were scored for sleep/wake and cataplexy. At all doses tested, TAK-925 and ARN-776 caused continuous wakefulness and eliminated sleep for the first hour. Both TAK-925 and ARN-776 caused dose-related delays in NREM sleep onset. All doses of TAK-925 and all but the lowest dose of ARN-776 eliminated cataplexy during the first hour after treatment; the anti-cataplectic effect of TAK-925 persisted into the second hour for the highest dose. TAK-925 and ARN-776 also reduced the cumulative amount of cataplexy during the 6 h post-dosing period. The acute increase in wakefulness produced by both HCRTR2 agonists was characterised by increased spectral power in the gamma EEG band. Although neither compound provoked a NREM sleep rebound, both compounds affected NREM EEG during the second hour post-dosing. TAK-925 and ARN-776 also increased gross motor activity, running wheel activity, and Tsc , suggesting that the wake-promoting and sleep-suppressing activities of these compounds could be a consequence of hyperactivity. Nonetheless, the anti-cataplectic activity of TAK-925 and ARN-776 is encouraging for the development of HCRTR2 agonists.

Pharmacological options for narcolepsy: are they the way forward?

INTRODUCTION

Narcolepsy is an under-recognized, rare neurologic disorder of hypersomnolence that is associated with increased mortality and medical and psychiatric co-morbidities. Narcolepsy exerts a substantial economic burden on patients and society. There is currently no cure, and life-long symptomatic therapy is needed. Available drugs do not modify the disease course.

AREAS COVERED

This manuscript provides an overview of narcolepsy symptoms, diagnosis, pathophysiology, current pharmacotherapies, and emerging treatments. Gaps and unresolved issues in diagnosis and management of narcolepsy are discussed to answer whether pharmacological options are the way forward.

EXPERT OPINION

Diagnostic criteria for narcolepsy (ICSD-3) need revision and greater clarity. Improved recognition of cataplexy and other symptoms through educational outreach, new biomarkers, improved test scoring through artificial intelligence algorithms, and use of machine learning may facilitate earlier diagnosis and treatment. Pharmacological options need improved symptomatic therapy in addition to targeted therapies that address the loss of hypocretin signaling. Optimal narcolepsy care also needs a better understanding of the pathophysiology, recognition of the different phenotypes in narcolepsy, identification of at-risk individuals and early recognition of symptoms, better diagnostic tools, and a database for research and disease monitoring of treatment, side-effects, and comorbidities.

A multicenter, double-blind, placebo-controlled, randomized, Phase 1b crossover trial comparing two doses of ulotaront with placebo in the treatment of narcolepsy-cataplexy

BACKGROUND

Ulotaront (SEP-363856) is a novel agonist at trace amine-associated receptor 1 and serotonin 5-HT_1A receptors in clinical development for the treatment of schizophrenia. Previous studies demonstrated ulotaront suppresses rapid eye movement (REM) sleep in both rodents and healthy volunteers. We assessed acute and sustained treatments of ulotaront on REM sleep and symptoms of cataplexy and alertness in subjects with narcolepsy-cataplexy.

METHODS

In a multicenter, double-blind, placebo-controlled, randomized, 3-way crossover study, ulotaront was evaluated in 16 adults with narcolepsy-cataplexy. Two oral doses of ulotaront (25 mg and 50 mg) were administered daily for 2 weeks and compared with matching placebo (6-treatment sequence, 3-period, 3-treatment).

RESULTS

Acute treatment with both 25 mg and 50 mg of ulotaront reduced minutes spent in nighttime REM compared to placebo. A sustained 2-week administration of both doses of ulotaront reduced the mean number of short-onset REM periods (SOREMPs) during daytime multiple sleep latency test (MSLT) compared to placebo. Although cataplexy events decreased from the overall mean baseline during the 2-week treatment period, neither dose of ulotaront statistically separated from placebo (p = 0.76, 25 mg; p = 0.82, 50 mg), and no significant improvement in patient and clinician measures of sleepiness from baseline to end of the 2-week treatment period occurred in any treatment group.

CONCLUSIONS

Acute and sustained treatment with ulotaront reduced nighttime REM duration and daytime SOREMPs, respectively. The effect of ulotaront on suppression of REM did not demonstrate a statistical or clinically meaningful effect in narcolepsy-cataplexy.

REGISTRATION

ClinicalTrials.gov identifier: NCT05015673.

Safety and efficacy of pitolisant in children aged 6 years or older with narcolepsy with or without cataplexy: a double-blind, randomised, placebo-controlled trial

BACKGROUND

Narcolepsy is a life-long disorder characterised by excessive daytime sleepiness and cataplexy, often arising in childhood or adolescence. Pitolisant, a selective histamine H3 receptor inverse agonist, has been approved in Europe and USA for adults with narcolepsy with or without cataplexy, with a favourable safety profile. This phase 3 study aimed to assess the safety and efficacy of pitolisant in children with narcolepsy with or without cataplexy.

METHODS

For this double-blind, randomised, placebo-controlled, multisite study, we recruited patients aged 6-17 years with narcolepsy with or without cataplexy in 11 sleep centres in five countries (Italy, France, Netherlands, Russia, and Finland). Participants were required to have a Pediatric Daytime Sleepiness Scale score of 15 or greater and to have not received psychostimulants for at least 14 days before enrolment; participants who needed anticataplectics (including sodium oxybate) were required to have been on a stable dose for at least 1 month. Participants were randomly assigned to treatment with pitolisant or placebo in a 2:1 ratio at the end of screening. Randomisation was stratified by study centre and treatment was allocated using an interactive web response system. After a 4-week screening period including a 2-week baseline period, patients entered in a 4-week individual up-titration scheme from 5 mg a day to a maximum of 40 mg a day of pitolisant or placebo; treatment was administered at a stable dose for 4 weeks, followed by a 1-week placebo period. For the primary analysis, we assessed pitolisant versus placebo using change in the Ullanlinna Narcolepsy Scale (UNS) total score from baseline to the end of double-blind period in the full analysis set, defined as all randomly allocated patients who received at least one dose of treatment and who had at least one baseline UNS value. A decrease in the UNS total score reflects a reduction in both excessive daytime sleepiness and cataplexy. All adverse events were assessed in the safety population, defined as all participants who took at least one dose of study medication. An open-label follow-up is ongoing. This study is registered at ClinicalTrials.gov, NCT02611687.

FINDINGS

Between June 6, 2016, and April 3, 2021, we screened 115 participants and 110 were randomly assigned (mean age 12·9 [SD 3·0] years, 61 [55%] male, and 90 [82%] with cataplexy; 72 assigned to pitolisant and 38 to placebo); 107 (70 receiving pitolisant and 37 receiving placebo) completed the double-blind period. The mean adjusted difference in UNS total score from baseline to the end of the double-blind period was -6·3 (SE 1·1) in the pitolisant group and -2·6 (1·4) in the placebo group (least squares mean difference -3·7; 95% CI -6·4 to -1·0, p=0·007). Treatment-emergent adverse events were reported in 22 (31%) of 72 patients in the pitolisant group and 13 (34%) of 38 patients in the placebo group. The most frequently reported adverse events (affecting ≥5% of patients) in either group were headache (14 [19%] in the pitolisant group and three [8%] in the placebo group) and insomnia (five [7%] in the pitolisant group and one [3%] in the placebo group).

INTERPRETATION

Pitolisant treatment resulted in an improvement in narcolepsy symptoms in children, although the UNS was not validated for use in children with narcolepsy when our study began. The safety profile was similar to that reported in adults but further studies are needed to confirm long-term safety.

FUNDING

Bioprojet.

Genetics of circadian rhythms and sleep in human health and disease

Circadian rhythms and sleep are fundamental biological processes integral to human health. Their disruption is associated with detrimental physiological consequences, including cognitive, metabolic, cardiovascular and immunological dysfunctions. Yet many of the molecular underpinnings of sleep regulation in health and disease have remained elusive. Given the moderate heritability of circadian and sleep traits, genetics offers an opportunity that complements insights from model organism studies to advance our fundamental molecular understanding of human circadian and sleep physiology and linked chronic disease biology. Here, we review recent discoveries of the genetics of circadian and sleep physiology and disorders with a focus on those that reveal causal contributions to complex diseases.

Psychotic Episode and Schizophrenia in Slovakian Narcolepsy Database

Narcolepsy type 1 (NT1), a central disorder of hypersomnolence, is associated with mood, anxiety or hyperactivity mental disorders. Association with psychotic episode or schizophrenia is rare and could be the source of diagnostic and therapeutic difficulties. Their frequency in the national narcolepsy database has not been systematically studied. The aim of the presented study was to calculate the frequency of NT1 patients diagnosed with psychosis and/or schizophrenia, to identify clinical characteristics of these cases, and to look for narcoleptic and psychotic symptoms during re-evaluation years later. We identified three (4%) cases diagnosed with a psychotic episode in the course of NT1. They were diagnosed with NT1 by age ≤18 years. In the re-evaluation (mean follow-up 9.8 years), we identified one case with a dual diagnosis of NT1 and schizophrenia; two cases were diagnosed with a solitary psychotic episode in the course of NT1. NT1 patients diagnosed in the age ≤18 years are at higher risk of psychotic episode, and this may be related to higher vulnerability during the ongoing neurodevelopmental period. Comorbid schizophrenia with NT1 in the Slovakian Narcolepsy Database was within the prevalence expected in the general population. The solitary psychotic episode in the course of NT1 did not reduce the possibility of subsequent symptomatic treatment afterwards.

Modulation of sleep behavior in zebrafish larvae by pharmacological targeting of the orexin receptor

New pharmacological approaches that target orexin receptors (OXRs) are being developed to treat sleep disorders such as insomnia and narcolepsy, with fewer side effects than existing treatments. Orexins are neuropeptides that exert excitatory effects on postsynaptic neurons via the OXRs, and are important in regulating sleep/wake states. To date, there are three FDA-approved dual orexin receptor antagonists for the treatment of insomnia, and several small molecule oral OX2R (OXR type 2) agonists are in the pipeline for addressing the orexin deficiency in narcolepsy. To find new hypnotics and psychostimulants, rodents have been the model of choice, but they are costly and have substantially different sleep patterns to humans. As an alternative model, zebrafish larvae that like humans are diurnal and show peak daytime activity and rest at night offer several potential advantages including the ability for high throughput screening. To pharmacologically validate the use of a zebrafish model in the discovery of new compounds, we aimed in this study to evaluate the functionality of a set of known small molecule OX2R agonists and antagonists on human and zebrafish OXRs and to probe their effects on the behavior of zebrafish larvae. To this end, we developed an in vitro IP-One Homogeneous Time Resolved Fluorescence (HTRF) immunoassay, and in vivo locomotor assays that record the locomotor activity of zebrafish larvae under physiological light conditions as well as under dark-light triggers. We demonstrate that the functional IP-One test is a good predictor of biological activity in vivo. Moreover, the behavioral data show that a high-throughput assay that records the locomotor activity of zebrafish throughout the evening, night and morning is able to distinguish between OXR agonists and antagonists active on the zebrafish OXR. Conversely, a locomotor assay with alternating 30 min dark-light transitions throughout the day is not able to distinguish between the two sets of compounds, indicating the importance of circadian rhythm to their pharmacological activity. Overall, the results show that a functional IP-one test in combination with a behavioral assay using zebrafish is well-suited as a discovery platform to find novel compounds that target OXRs for the treatment of sleep disorders.

What respiratory physicians should know about narcolepsy and other hypersomnias

Narcolepsy and related central disorders of hypersomnolence may present to the sleep clinic with excessive daytime sleepiness. A strong clinical suspicion and awareness of the diagnostic clues, such as cataplexy, are essential to avoid unnecessary diagnostic delay. This review provides an overview of the epidemiology, pathophysiology, clinical features, diagnostic criteria and management of narcolepsy and related disorders, including idiopathic hypersomnia, Kleine-Levin syndrome (recurrent episodic hypersomnia) and secondary central disorders of hypersomnolence.

Treatment of Narcolepsy: A Rare Disease of Unknown Etiology

Background:

Narcolepsy, also known as Gélineau syndrome, is a chronic and neurological disease that affects 0.05% of the European population, though that percentage could be higher due to the diagnostic difficulties. The main symptom is excessive daytime sleepiness, although it may be accompanied by cataplexy, sleep paralysis and hypnagogic hallucinations.

Objective:

Nowadays, there is no cure for narcolepsy, and the treatment is symptomatic; psychostimulants for sleepiness by means of amphetamines, methylphenidate, or modafinil, and antidepressants and sodium oxybate for treating cataplexy.

Method:

This is a short review regarding pharmacotherapy for narcolepsy.

Result:

Hypocretins were discovered in 1998. They are neuropeptides whose deficiency is responsible for this symptomatology, which has opened up a new field of investigation.

Conclusion:

Agonists of hypocretins could be a promising therapy against this disease.

Orexin 2 receptor-selective agonist danavorexton improves narcolepsy phenotype in a mouse model and in human patients

Narcolepsy type 1 (NT1) is a sleep disorder caused by a loss of orexinergic neurons. Narcolepsy type 2 (NT2) is heterogeneous; affected individuals typically have normal orexin levels. Following evaluation in mice, the effects of the orexin 2 receptor (OX2R)-selective agonist danavorexton were evaluated in single- and multiple-rising-dose studies in healthy adults, and in individuals with NT1 and NT2. In orexin/ataxin-3 narcolepsy mice, danavorexton reduced sleep/wakefulness fragmentation and cataplexy-like episodes during the active phase. In humans, danavorexton administered intravenously was well tolerated and was associated with marked improvements in sleep latency in both NT1 and NT2. In individuals with NT1, danavorexton dose-dependently increased sleep latency in the Maintenance of Wakefulness Test, up to the ceiling effect of 40 min, in both the single- and multiple-rising-dose studies. These findings indicate that OX2Rs remain functional despite long-term orexin loss in NT1. OX2R-selective agonists are a promising treatment for both NT1 and NT2.

Pediatric Narcolepsy-A Practical Review

Pediatric narcolepsy is a chronic sleep-wakefulness disorder. Its symptoms frequently begin in childhood. This review article examined the literature for research reporting on the effects of treatment of pediatric narcolepsy, as well as proposed etiology and diagnostic tools. Symptoms of pediatric narcolepsy include excessive sleepiness and cataplexy. In addition, rapid-eye-movement-related phenomena such as sleep paralysis, sleep terror, and hypnagogic or hypnapompic hallucinations can also occur. These symptoms impaired children's function and negatively influenced their social interaction, studying, quality of life, and may further lead to emotional and behavioral problems. Therefore, early diagnosis and intervention are essential for children's development. Moreover, there are differences in clinical experiences between Asian and Western population. The treatment of pediatric narcolepsy should be comprehensive. In this article, we review pediatric narcolepsy and its treatment approach: medication, behavioral modification, and education/mental support. Pharmacological treatment including some promising newly-developed medication can decrease cataplexy and daytime sleepiness in children with narcolepsy. Other forms of management such as psychosocial interventions involve close cooperation between children, school, family, medical personnel, and can further assist their adjustment.

The orexin story, sleep and sleep disturbances

The orexins, also known as hypocretins, are two neuropeptides (orexin A and B or hypocretin 1 and 2) produced by a few thousand neurons located in the lateral hypothalamus that were independently discovered by two research groups in 1998. Those two peptides bind two receptors (orexin/hypocretin receptor 1 and receptor 2) that are widely distributed in the brain and involved in the central physiological regulation of sleep and wakefulness, orexin receptor 2 having the major role in the maintenance of arousal. They are also implicated in a multiplicity of other functions, such as reward seeking, energy balance, autonomic regulation and emotional behaviours. The destruction of orexin neurons is responsible for the sleep disorder narcolepsy with cataplexy (type 1) in humans, and a defect of orexin signalling also causes a narcoleptic phenotype in several animal species. Orexin discovery is unprecedented in the history of sleep research, and pharmacological manipulations of orexin may have multiple therapeutic applications. Several orexin receptor antagonists were recently developed as new drugs for insomnia, and orexin agonists may be the next-generation drugs for narcolepsy. Given the broad range of functions of the orexin system, these drugs might also be beneficial for treating various conditions other than sleep disorders in the near future.

Linking clinical complaints and objective measures of disrupted nighttime sleep in narcolepsy type 1

STUDY OBJECTIVES

Despite its high frequency in narcolepsy type 1(NT1), disrupted nocturnal sleep (DNS) remains understudied, and its determinants have been poorly assessed. We aimed to determine the clinical, polysomnographic (PSG), and biological variables associated with DNS in a large sample of patients with NT1, and to evaluate the effect of medication on DNS and its severity.

METHODS

Two hundred and forty-eight consecutive adult patients with NT1 (145 untreated, 103 treated) were included at the National Reference Center for Narcolepsy-France; 51 drug-free patients were reevaluated during treatment. DNS, assessed with the Narcolepsy Severity Scale (NSS), was categorized in four levels (absent, mild, moderate, severe). Clinical characteristics, validated questionnaires, PSG parameters (sleep fragmentation markers: sleep (SB) and wake bouts (WB), transitions), objective sleepiness, and orexin-A levels were assessed.

RESULTS

In drug-free patients, DNS severity was associated with higher scores on NSS, higher sleepiness, anxiety/depressive symptoms, autonomic dysfunction, worse quality of life (QoL). Patients with moderate/severe DNS (59%) had increased sleep onset REM periods, lower sleep efficiency, longer wake after sleep onset, more N1, SB, WB, sleep instability, transitions. In treated patients, DNS was associated with the same clinical data, and antidepressant use; but only with longer REM sleep latency on PSG. During treatment, sleepiness, NSS scores, depressive symptoms decreased, as well as total sleep time, WB, SB, transitions. DNS improved in 55% of patients, without predictors except more baseline anxiety.

CONCLUSION

DNS complaint is frequent in NT1, associated with disease severity based on NSS, several PSG parameters, and objective sleepiness in untreated and treated conditions. DNS improves with treatment. We advocate the systematic assessment of this symptom and its inclusion in NT1 management strategy.

pitolisant, a novel histamine-3 receptor competitive antagonist, and inverse agonist, in the treatment of excessive daytime sleepiness in adult patients with narcolepsy

Narcolepsy is a debilitating sleep disorder that presents with excessive daytime sleepiness (EDS) and cataplexy, which is a sudden paralysis of muscle tone triggered by strong emotions such as laughing. It is also associated with many other disorders, including psychiatric disorders, neurologic illnesses, and medication side effects. Common causes of delayed and incorrect diagnoses of these conditions include lack of physician familiarity with narcolepsy symptoms and comorbidities which mask narcolepsy signs and symptoms. Current pharmacologic therapies include Modafinil and Armodafinil for EDS and sodium oxybate for cataplexy. This review discusses the epidemiology, pathophysiology, risk factors, presentation, treatment of narcolepsy, and the role of a novel drug, Pitolisant, in the treatment of EDS in adults with narcolepsy. Pitolisant is a histamine-3 receptor (H3R), competitive antagonist, and inverse agonist, acting through the histamine system to regulate wakefulness. It is a novel drug approved in August 2019 by the FDA, is not classified as a controlled substance, and is approved for use in Europe and the United States to treat EDS and cataplexy in narcolepsy. Recent phase II and III trials have shown that Pitolisant helps reduce the ESS score and cataplexy. In summary, based on comparative studies, recent evidence has shown that Pitolisant is non-inferior to Modafinil in the treatment of EDS but superior to Modafinil in reducing cataplexy.

50th anniversary of the ESRS in 2022-JSR special issue

This article addresses the clinical presentation, diagnosis, pathophysiology and management of narcolepsy type 1 and 2, with a focus on recent findings. A low level of hypocretin-1/orexin-A in the cerebrospinal fluid is sufficient to diagnose narcolepsy type 1, being a highly specific and sensitive biomarker, and the irreversible loss of hypocretin neurons is responsible for the main symptoms of the disease: sleepiness, cataplexy, sleep-related hallucinations and paralysis, and disrupted nocturnal sleep. The process responsible for the destruction of hypocretin neurons is highly suspected to be autoimmune, or dysimmune. Over the last two decades, remarkable progress has been made for the understanding of these mechanisms that were made possible with the development of new techniques. Conversely, narcolepsy type 2 is a less well-defined disorder, with a variable phenotype and evolution, and few reliable biomarkers discovered so far. There is a dearth of knowledge about this disorder, and its aetiology remains unclear and needs to be further explored. Treatment of narcolepsy is still nowadays only symptomatic, targeting sleepiness, cataplexy and disrupted nocturnal sleep. However, new psychostimulants have been recently developed, and the upcoming arrival of non-peptide hypocretin receptor-2 agonists should be a revolution in the management of this rare sleep disease, and maybe also for disorders beyond narcolepsy.

Metabolic-Syndrome-Related Comorbidities in Narcolepsy Spectrum Disorders: A Preliminary Cross-Sectional Study in Japan

Narcolepsy types 1 (NT1) and 2 (NT2) and idiopathic hypersomnia (IH) are thought to be a disease continuum known as narcolepsy spectrum disorders (NSDs). This study aimed to assess the prevalence of and factors associated with metabolic-syndrome-related disorders (MRDs) among patients with NSD. Japanese patients with NSD (NT1, n = 94; NT2, n = 83; and IH, n = 57) aged ≥35 years were enrolled in this cross-sectional study. MRD was defined as having at least one of the following conditions: hypertension, diabetes, or dyslipidemia. Demographic variables and MRD incidence were compared among patients in the respective NSD categories. Multivariate logistic regression analysis was used to investigate the factors associated with MRDs. Patients with NT1 had a higher body mass index (BMI) and incidence of MRD than that had by those with NT2 or IH. Age, BMI, and the presence of OSA were significantly associated with the incidence of MRD in NSDs. Age and BMI in NT1, BMI and human leukocyte antigen (HLA)-DQB1*06:02 positivity in NT2, and only age in IH were factors associated with the incidence of MRD. Obesity should be carefully monitored in narcolepsy; however, NT2 with HLA-DQB1*06:02 positive should be followed up for the development of MRD even without obesity.

Optimal dose determination of enerisant (TS-091) for patients with narcolepsy: two randomized, double-blind, placebo-controlled trials

BACKGROUND

The histamine H3 receptor has emerged as one of the most promising targets of novel pharmacotherapy for narcolepsy. Studies now aim to investigate the optimal dose of enerisant, a novel H3 antagonist/inverse agonist, for the treatment of excessive daytime sleepiness in patients with narcolepsy.

METHODS

We conducted two phase 2, fixed-dose, double-blind, randomized, placebo-controlled trials in patients with narcolepsy. The first phase 2 study (Study 1) was conducted to investigate the efficacy and safety of enerisant at dosages of 25, 50, and 100 mg/day administered for 3 weeks based on the results of a phase 1 study conducted on healthy volunteers. The primary endpoint was mean sleep latency in maintenance of wakefulness test (MWT), and the secondary endpoint was the total score on the Epworth Sleepiness Scale (ESS). The dosages of enerisant in the second phase 2 study (Study 2) were set at 5 and 10 mg/day based on the simulation of receptor occupancy results from positron emission tomography study.

RESULTS

Forty-six and fifty-three patients were randomized in Study 1 and Study 2, respectively. The efficacy of enerisant was partially confirmed in Study 1 with ESS; however, the doses were not tolerated, and there were many withdrawals due to adverse events (mainly insomnia, headache, and nausea). The doses in Study 2 were well tolerated, with a lower incidence of adverse events in Study 2 than in Study 1, although the efficacy could not be confirmed with MWT and ESS in Study 2.

CONCLUSIONS

The optimal dose of enerisant could not be determined in these two studies. Although enerisant has a favorable pharmacokinetic profile, it is thought to have large interindividual variabilities in terms of efficacy and safety, suggesting the necessity of tailored dosage adjustments.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03267303 ; Registered 30 August 2017 (Study 2). Japic identifier: JapicCTI-142529 ; Registered 7 May 2014 (Study 1) and JapicCTI-173689 ; Registered 30 August 2017, https://www.clinicaltrials.jp/cti-user/trial/ShowDirect.jsp?clinicalTrialId=29277 (Study 2).

Pharmacologic Therapy for Narcolepsy

Narcolepsy is a lifelong disorder that adversely affects daytime function and quality of life. Major symptoms include excessive daytime sleepiness with irrepressible sleep attacks and cataplexy. Recent developments in the understanding of the pathobiology of narcolepsy, as well as the neuronal systems involved in the regulation of wakefulness have led to development of new pharmacologic approaches to therapy. In this paper, we review available pharmacologic treatments for narcolepsy as well as agents currently under investigation.

Clinical Impact of Pitolisant on Excessive Daytime Sleepiness and Cataplexy in Adults With Narcolepsy: An Analysis of Randomized Placebo-Controlled Trials

BACKGROUND

Pitolisant, a selective histamine 3 receptor antagonist/inverse agonist, is indicated for the treatment of excessive daytime sleepiness or cataplexy in adults with narcolepsy. The efficacy and safety of pitolisant have been demonstrated in randomized placebo-controlled trials. When evaluating the results of randomized placebo-controlled trials, the clinical impact of a treatment can be assessed using effect size metrics that include Cohen's d (the standardized mean difference of an effect) and number needed to treat (NNT; number of patients that need to be treated to achieve a specific outcome for one person).

OBJECTIVE

The objective of this study was to evaluate the clinical impact of pitolisant for the reduction in excessive daytime sleepiness or cataplexy in adults with narcolepsy.

METHODS

This post hoc analysis incorporated data from two 7-week or 8-week randomized placebo-controlled trials (HARMONY 1, HARMONY CTP). Study medication was individually titrated, with a maximum possible pitolisant dose of 35.6 mg/day. Efficacy was assessed using the Epworth Sleepiness Scale (ESS) and weekly rate of cataplexy (HARMONY CTP only). Cohen's d was derived from the least-squares mean difference between treatment groups (pitolisant vs placebo), and NNTs were calculated from response rates. Treatment response was defined for excessive daytime sleepiness in two ways: (a) reduction in ESS score ≥ 3 or final ESS score ≤ 10 and (b) final ESS score ≤ 10. Treatment response was defined for cataplexy as a ≥ 25%, ≥ 50%, or ≥ 75% reduction in weekly rate of cataplexy.

RESULTS

The analysis population included 61 patients in HARMONY 1 (pitolisant, n = 31; placebo, n = 30) and 105 patients in HARMONY CTP (pitolisant, n = 54; placebo, n = 51). For pitolisant vs placebo, Cohen's d effect size values were 0.61 (HARMONY 1) and 0.86 (HARMONY CTP) based on changes in ESS scores, and 0.86 (HARMONY CTP) based on changes in weekly rate of cataplexy. NNTs for pitolisant were 3-5 for the treatment of excessive daytime sleepiness and 3-4 for the treatment of cataplexy.

CONCLUSIONS

The results of this analysis demonstrate the robust efficacy of pitolisant for the reduction in both excessive daytime sleepiness and cataplexy. These large effect sizes and low NNTs provide further evidence supporting the strength of the clinical response to pitolisant in the treatment of adults with narcolepsy.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identifiers: NCT01067222 (February 2010), NCT01800045 (February 2013).

Time to Onset of Response to Pitolisant for the Treatment of Excessive Daytime Sleepiness and Cataplexy in Patients With Narcolepsy: An Analysis of Randomized, Placebo-Controlled Trials

BACKGROUND

Pitolisant is approved in the USA and Europe for the treatment of excessive daytime sleepiness or cataplexy in adults with narcolepsy.

OBJECTIVE

Analyses evaluated the time to onset of clinical response during treatment with pitolisant.

METHODS

Data were obtained from two randomized, double-blind, 7-week or 8-week, placebo-controlled studies (HARMONY 1, HARMONY CTP). Study medication was individually titrated to a maximum dose of pitolisant 35.6 mg/day and then remained stable. Efficacy assessments included the Epworth Sleepiness Scale and weekly rate of cataplexy (calculated from patient diaries). Onset of clinical response was defined as the first timepoint at which there was statistical separation between pitolisant and placebo.

RESULTS

The analysis included 61 patients in HARMONY 1 (pitolisant, n = 31; placebo, n = 30) and 105 patients in HARMONY CTP (pitolisant, n = 54; placebo, n = 51). Onset of clinical response began at week 2 (HARMONY 1) or week 3 (HARMONY CTP) for the mean change in Epworth Sleepiness Scale score, and week 2 (HARMONY CTP) or week 5 (HARMONY 1) for the mean change in weekly rate of cataplexy, with further improvements observed in pitolisant-treated patients through the end of treatment. The percentage of treatment responders was significantly greater with pitolisant vs placebo beginning at week 3 for excessive daytime sleepiness (defined as an Epworth Sleepiness Scale score reduction ≥ 3) and week 2 for cataplexy (defined as a ≥ 50% reduction in weekly rate of cataplexy [HARMONY CTP]).

CONCLUSIONS

Onset of clinical response for excessive daytime sleepiness and/or cataplexy was generally observed within the first 2-3 weeks of pitolisant treatment in patients with narcolepsy. CLINICALTRIALS.

GOV IDENTIFIER

NCT01067222 (February 2010), NCT01800045 (February 2013).

Pharmacokinetics of FT218, a Once-Nightly Sodium Oxybate Formulation in Healthy Adults

PURPOSE

FT218 is an investigational, once-nightly, modified-release formulation of sodium oxybate (SO). SO effectively treats excessive daytime sleepiness and cataplexy in patients with narcolepsy. Current approved SO formulations, at effective doses of 6, 7.5, and 9 g, require twice-nightly divided dosing, with the first dose taken at bedtime and the second 2.5-4 h later. The purpose of the following studies was to evaluate the pharmacokinetic properties, safety profile, and tolerability of FT218 in healthy adults.

METHODS

Four crossover, single-dose studies were conducted. The first was a pilot study (n = 16) that compared 3 prototype formulations of FT218 4.5 g to twice-nightly SO 4.5 g (2 divided doses of 2.25 g); the second, a dose-proportionality study (n = 20) that evaluated FT218 4.5, 7.5, and 9 g; the third, a relative bioavailability study (n = 28) that compared FT218 6 g with twice-nightly SO 6 g (2 divided doses of 3 g); and the fourth, a food-effect study (n = 16) of FT218 6 g.

RESULTS

In the pilot study, FT218 prototype 2 had a lower C_max, lower plasma concentration 8 h after dosing (C_8h), similar exposure (AUC), and comparable interperson variability to twice-nightly SO 4.5 g. Exploratory pharmacodynamic data indicated similar sleep quality and morning alertness between FT218 and twice-nightly SO. Prototype 2 was selected for further development. In the dose-proportionality study, FT218 had dose proportionality for C_max and slightly more than dose proportionality for AUC. The relative bioavailability study confirmed that FT218 6 g had lower C_max and C_8h than twice-nightly SO 6 g but equivalent AUC and comparable variability. In the food-effect study, FT218 6 g had longer t_max (1 h later), lower C_max (67%), and decreased AUC (86%) in fed versus fasted states. For all studies, adverse events with FT218 were mostly mild or moderate in severity, nonserious, and known to be associated with SO. Most common adverse events included somnolence, dizziness, and nausea. Safety profiles of FT218 and twice-nightly SO at 4.5 and 6 g were similar.

IMPLICATIONS

Once-nightly FT218 at 4.5 and 6 g had lower overall C_max and C_8h and similar exposure and variability compared with twice-nightly SO. FT218 was generally well tolerated and comparable to twice-nightly SO.

Sleep Disorders in dogs: A Pathophysiological and Clinical Review

Sleep is a fundamental process in mammals, including domestic dogs. Disturbances in sleep affect physiological functions like cognitive and physical performance, immune response, pain sensation and increase the risk of diseases. In dogs, sleep can be affected by several conditions, with narcolepsy, REM sleep behavior disorder and sleep breathing disorders being the most frequent causes. Furthermore, sleep disturbances can be a symptom of other primary diseases where they can contribute to the worsening of clinical signs. This review describes reciprocally interacting sleep and wakefulness promoting systems and how their dysfunction can explain the pathophysiological mechanisms of sleep disorders. Additionally, this work discusses the clinical characteristics, diagnostic tools and available treatments for these disorders while highlighting areas in where further studies are needed so as to improve their treatment and prevention.

Mutual Relationship Between Sleep Disorders, Quality of Life and Psychosocial Aspects in Patients With Psoriasis

Psoriasis is a chronic, autoimmune skin disease affecting about 2-4% of the worldwide population. It is now perceived as a systemic disease because of the complex pathogenesis and multiple comorbidities. It leads to decreased quality of life and productivity of patients. Nowadays, sleep disorders are investigated as well in relation to psoriasis as another possible comorbidity. This review focuses on possible negative effects of sleep deprivation, decreased quality of life, and psychosocial status in patients with psoriasis and highlights their mutual, complex relationship of divergent consequences. The relationship between sleep disorders and psychosocial status in patients with psoriasis is bidirectional and resembles a vicious circle, one abnormality triggering the other. Sleep disorders additionally increase the risk of metabolic and psychiatric diseases in psoriatic patients who are already at increased risk of developing such disorders. There should be measures taken to screen patients with psoriasis for sleep disorders in order to diagnose early and treat.

Gut microbiota composition is associated with narcolepsy type 1

OBJECTIVE

To test the hypothesis that narcolepsy type 1 (NT1) is related to the gut microbiota, we compared the microbiota bacterial communities of patients with NT1 and control subjects.

METHODS

Thirty-five patients with NT1 (51.43% women, mean age 38.29 ± 19.98 years) and 41 controls (57.14% women, mean age 36.14 ± 12.68 years) were included. Stool samples were collected, and the fecal microbiota bacterial communities were compared between patients and controls using the well-standardized 16S rRNA gene amplicon sequencing approach. We studied alpha and beta diversity and differential abundance analysis between patients and controls, and between subgroups of patients with NT1.

RESULTS

We found no between-group differences for alpha diversity, but we discovered in NT1 a link with NT1 disease duration. We highlighted differences in the global bacterial community structure as assessed by beta diversity metrics even after adjustments for potential confounders as body mass index (BMI), often increased in NT1. Our results revealed differential abundance of several operational taxonomic units within Bacteroidetes, Bacteroides, and Flavonifractor between patients and controls, but not after adjusting for BMI.

CONCLUSION

We provide evidence of gut microbial community structure alterations in NT1. However, further larger and longitudinal multiomics studies are required to replicate and elucidate the relationship between the gut microbiota, immunity dysregulation and NT1.

Depression and suicidal thoughts in untreated and treated narcolepsy: Systematic analysis

OBJECTIVES

To assess the frequency and determinants of depressive symptoms and suicidal thoughts in adults with narcolepsy type 1 (NT1) and controls, as well as the changes after NT1 management and the risk factors of major depressive episode (MDE) and suicide risk (SR) in NT1.

METHODS

Two hundred ninety-seven patients with NT1 (age 39 ± 17 years, 172 drug-free) and 346 controls (age 38 ± 16 years) underwent a comprehensive clinical evaluation including the Beck Depression Inventory-II (BDI-II) self-questionnaire, with 1 item on suicidal thoughts. One hundred one drug-free patients with NT1 completed the BDI-II a second time during treatment. In 162 patients with NT1, the face-to-face Mini International Neuropsychiatric Interview was performed to formally diagnose current MDE and SR.

RESULTS

BDI-II total scores were higher in patients with NT1 than controls and in untreated than treated patients. Patients with moderate to severe BDI-II scores (24.9%) were less educated, were more frequently obese, and had more severe narcolepsy symptoms, more autonomic dysfunctions, and poorer quality of life. Results were unchanged in models adjusted for NT1 medication intake. Suicidal thoughts were more frequent in untreated patients than controls (22.7% vs 12.4%). Patients with suicidal thoughts were more likely to be men and to have more severe narcolepsy symptoms. After narcolepsy management, BDI-II total score and suicidal thoughts decreased. MDE was diagnosed in 29 (18.1%) and SR in 27 (16.9%) patients.

CONCLUSIONS

Depression, depressive symptoms, suicidal thoughts, and SR were frequent in patients with NT1, especially those without treatment, and were associated with NT1 severity. Depressive symptoms and suicidal thoughts improved after NT1 management.

The sodium in sodium oxybate: is there cause for concern?

Sodium oxybate (SO), the sodium salt of γ-hydroxybutyric acid, is one of the primary pharmacologic agents used to treat excessive sleepiness, disturbed nighttime sleep, and cataplexy in narcolepsy. The sodium content of SO ranges from 550 to 1640 mg at 3-9 g, given in two equal nightly doses. Clinicians are advised to consider daily sodium intake in patients with narcolepsy who are treated with SO and have comorbid disorders associated with increased cardiovascular (CV) risk, in whom sodium intake may be a concern. It remains unclear whether all patients with narcolepsy treated with SO should modify or restrict their sodium intake. No data are currently available specific to the sodium content or threshold of SO at which patients might experience increased CV risk. To appraise attributable risk, critical evaluation of the literature was conducted to examine the relationship between CV risk and sodium intake, narcolepsy, and SO exposure. The findings suggest that increased CV risk is associated with extremes of daily sodium intake, and that narcolepsy is associated with comorbidities that may increase CV risk in some patients. However, data from studies regarding SO use in patients with narcolepsy have shown a very low frequency of CV side effects (eg, hypertension) and no overall association with CV risk. In the absence of data that specifically address CV risk with SO based on its sodium content, the clinical evidence to date suggests that SO treatment does not confer additional CV risk in patients with narcolepsy.

Evaluating pitolisant as a narcolepsy treatment option

INTRODUCTION

Narcolepsy is a chronic sleep disorder characterized by a pentad of excessive daytime sleepiness (EDS), cataplexy, sleep paralysis, hypnagogic/hypnopompic hallucinations, and disturbed nocturnal sleep. Treatment of narcolepsy remains challenging and current therapy is strictly symptomatically based.

AREAS COVERED

The present manuscript is based on an extensive Internet and PubMed search from 1990 to 2020. It is focused on the clinical and pharmacological properties of pitolisant in the treatment of narcolepsy.

EXPERT OPINION

Currently there is no cure for narcolepsy. Although efforts have been made, current treatments do not always allow to obtain an optimal control of symptoms. Pitolisant is an antagonist/inverse agonist of the histamine H3 autoreceptor. Its mechanism of action is novel and distinctive compared to the other available therapies for narcolepsy. Clinical trials suggest that pitolisant administered at a dose of ≤36 mg/day is an effective treatment option for narcolepsy, reducing EDS and cataplexy. Pitolisant is available as oral tablets and offers a convenient once-daily regimen. Pitolisant is generally well tolerated and showed minimal abuse potential in animals and humans. Long-term studies comparing the effectiveness and tolerability of pitolisant with active drugs (e.g. modafinil, sodium oxybate) are needed.

Validation of Progression-Free Survival Rate at 6 Months and Objective Response for Estimating Overall Survival in Immune Checkpoint Inhibitor Trials: A Systematic Review and Meta-analysis

IMPORTANCE

Progression-free survival (PFS) rate at 6 months has been proposed as a potential surrogate for overall survival (OS) rate at 12 months for immune checkpoint inhibitor (ICI) trials but requires further assessment for validation.

OBJECTIVE

To validate 6-month PFS and objective response rate (ORR) as estimators of 12-month OS in the ICI arms of randomized clinical trials (RCTs).

DATA SOURCES

Electronic databases (Medline, EMBASE, and the Cochrane Central Register of Controlled Trials) were searched for ICI RCTs published between January 2000 and June 2019.

STUDY SELECTION

Eligible studies were phase 2 and phase 3 ICI RCTs in advanced solid cancers that reported ORR, PFS, and OS. A total of 99 articles (from 60 studies) of 2502 articles were selected by consensus.

DATA EXTRACTION AND SYNTHESIS

Data were screened and extracted independently. Estimation models for 12-month OS and to assess correlation coefficient between end points were developed using linear regression. Data were extracted in July 2019, and analyses were conducted in September 2019. This study is reported following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline.

MAIN OUTCOMES AND MEASURES

Validation of previously reported 6-month PFS and ORR estimation models for 12-month OS using contemporary RCTs. Calibration of 6-month PFS and ORR model-estimated vs observed 12-month OS in ICI arms were assessed by correlation coefficient (r) and weighted Brier scores. Secondary analyses were performed for subgroups (ie, ICI-only, ICI-combination, line of therapy, programmed cell death 1 ligand 1 selected, and unselected).

RESULTS

Data from 60 RCTs with 74 experimental ICI arms were used. The development data set included 25 arms from studies published January 2000 to January 2017. The estimation model for 12-month OS using 6-month PFS was: (1.06 × PFS6) + 0.16 + (0.04 × melanoma) - (0.03 × NSCLC) + (0 × other tumors), in which PFS6 indicates 6-month PFS and NSCLC indicates non-small cell lung cancer. The estimation model for 12-month OS using ORR was (0.15 × ORR) + 0.52 + (0 × melanoma) - (0.02 × NSCLC) - (0.01 × other tumors). A total of 49 arms from studies published after January 2017 to June 2019 formed the validation data set. When the models were applied on the validation data set, calibration between the 6-month PFS model estimated vs observed 12-month OS was good (r = 0.89; Brier score, 0.008), but poor for the ORR model (r = 0.47; Brier score, 0.03). Findings were similar across all subgroups.

CONCLUSIONS AND RELEVANCE

The findings of this study suggest that the estimation model using 6-month PFS could reliably estimate 12-month OS in ICI trials. This study could assist in better selection and prioritization of ICI agents for testing in RCTs based on phase 2 single-arm RCT results.

Association of CSF orexin-A levels and nocturnal sleep stability in patients with hypersomnolence

Objective

To evaluate the associations between CSF orexin-A (ORX) levels and markers of nocturnal sleep stability, assessed by polysomnography.

Methods

Nocturnal polysomnography data and ORX levels of 300 drug-free participants (55% men, 29.9±15.5 years, ORX level 155.1±153.7 pg/mL) with hypersomnolence were collected. Several markers of nocturnal sleep stability were analyzed: sleep and wake bouts and sleep/wake transitions. Groups were categorized according to ORX levels, in 2 categories (deficient ≤110; >110), in tertiles (≤26, 26–254, >254), and compared using logistic regression models. Results were adjusted for age, sex, and body mass index.

Results

We found higher number of wake bouts (43 vs 25, p < 0.0001), sleep bouts (43 vs 25.5, p < 0.0001), and index of sleep bouts/hour of sleep time, but lower index of wake bouts/hour of wake time (41.4 vs 50.6, p < 0.0001), in patients with ORX deficiency. The percentage of wake bouts <30 seconds was lower (51.3% vs 60.8%, p < 0.001) and of wake bouts ≥1 minutes 30 seconds higher (7.7% vs 6.7%, p = 0.02) when ORX deficient. The percentage of sleep bouts ≤14 minutes was higher (2–5 minutes: 23.7% vs 16.1%, p < 0.0001), and of long sleep bouts lower (>32 minutes 30 seconds: 7.3% vs 18.3%, p < 0.0001), when ORX deficient. These findings were confirmed when groups were categorized according to ORX tertiles, with a dose–response effect of ORX levels in post hoc comparisons, and in adjusted models.

Interpretation

This study shows an association between ORX levels and nocturnal sleep stabilization in patients with hypersomnolence. Sleep and wake bouts are reliable markers of nighttime sleep stability that correlate with CSF ORX levels in a dose-dependent manner.

[Advances in treatment of narcolepsy]

Narcolepsy is the most common cause of excessive daytime sleepiness (EDS) following obstructive sleep apnea. Its treatment aims to reduce EDS and cataplexy, improve nighttime sleep disturbance, sleep paralysis and sleep-related hallucinations. Pitolisant (a histamine H3 receptor antagonist) and solriamfetol (a norepinephrine reuptake inhibitor) have recently been approved effective for narcolepsy in the United States and the European Union. Pitolisant has proved to be effective for both EDS and cataplexy. Besides being effective on EDS, solriamfetol seems to have advantages in abuse potential and withdrawal syndrome. As potential treatments for EDS and cataplexy associated with narcolepsy, several new drugs are being developed and tested. These new drugs include new hydroxybutyrate preparations (controlled release sodium hydroxybutyrate FT218, low sodium hydroxybutyrate JZP-258), selective norepinephrine reuptake inhibitor (AXS-12), and modafinil combined with astroglial junction protein inhibitor (THN102). This paper reviews the recently approved drugs and potential treatments for narcolepsy.