Suvorexant in Patients With Insomnia: Results From Two 3-Month Randomized Controlled Clinical Trials

The Discovery of Suvorexant: Lessons Learned That Can Be Applied to Other CNS Drug Development Efforts

The development of therapeutics for central nervous system (CNS) disorders has many challenges that result in low probability of success and longer-than-typical development timelines. Suvorexant (Belsomra), the first dual orexin receptor antagonist used for insomnia, was approved by the United States Food and Drug Administration ∼10 years after the initial high-throughput screen was conducted to identify orexin receptor antagonists. What accounted for this success and speed? Here we suggest that this program was unique and set up for success by (1) having a robust and high-throughput pharmacodynamic readout that was translatable across species, including humans, (2) a well-validated target with a defined product profile, resulting in a highly energized team with a can-do attitude, and (3) a highly executable and streamlined clinical strategy. The utility of Belsomra for insomnia, as well as other neurological and psychiatric diseases, continues to be explored, most recently for insomnia associated with Alzheimer's disease.

The hypocretin (orexin) system: from a neural circuitry perspective

Hypocretin/orexin neurons are distributed restrictively in the hypothalamus, a brain region known to orchestrate diverse functions including sleep, reward processing, food intake, thermogenesis, and mood. Since the hypocretins/orexins were discovered more than two decades ago, extensive studies have accumulated concrete evidence showing the pivotal role of hypocretin/orexin in diverse neural modulation. New method of viral-mediated tracing system offers the possibility to map the monosynaptic inputs and detailed anatomical connectivity of Hcrt neurons. With the development of powerful research techniques including optogenetics, fiber-photometry, cell-type/pathway specific manipulation and neuronal activity monitoring, as well as single-cell RNA sequencing, the details of how hypocretinergic system execute functional modulation of various behaviors are coming to light. In this review, we focus on the function of neural pathways from hypocretin neurons to target brain regions. Anatomical and functional inputs to hypocretin neurons are also discussed. We further briefly summarize the development of pharmaceutical compounds targeting hypocretin signaling. This article is part of the special issue on Neuropeptides.

Polysomnographic assessment of suvorexant in patients with probable Alzheimer's disease dementia and insomnia: a randomized trial

Introduction

We evaluated the clinical profile of the orexin receptor antagonist suvorexant for treating insomnia in patients with mild‐to‐moderate probable Alzheimer's disease (AD) dementia.

Methods

Randomized, double‐blind, 4‐week trial of suvorexant 10 mg (could be increased to 20 mg based on clinical response) or placebo in patients who met clinical diagnostic criteria for both probable AD dementia and insomnia. Sleep was assessed by overnight polysomnography in a sleep laboratory. The primary endpoint was change‐from‐baseline in polysomnography‐derived total sleep time (TST) at week 4.

Results

Of 285 participants randomized (suvorexant, N = 142; placebo, N = 143), 277 (97%) completed the trial (suvorexant, N = 136; placebo, N = 141). At week 4, the model‐based least squares mean improvement‐from‐baseline in TST was 73 minutes for suvorexant and 45 minutes for placebo; (difference = 28 minutes [95% confidence interval 11‐45], p < 0.01). Somnolence was reported in 4.2% of suvorexant‐treated patients and 1.4% of placebo‐treated patients.

Discussion

Suvorexant improved TST in patients with probable AD dementia and insomnia.

Two-level approaches to missing data in longitudinal trials with daily patient-reported outcomes

In longitudinal clinical trials with daily patient-reported outcomes, the analysis endpoints are often defined as the averaged daily diary outcomes in a treatment cycle (such as a month or a week). Conventional methods often deal with missing data at the cycle level by imputing the average, and the cycle average is treated as missing if the number of days with available outcomes in the treatment cycle is less than a certain number. This was the method used for a case study of a phase 3 clinical trial evaluating a treatment for insomnia with daily patient-reported outcomes. Such methods may introduce bias. Motivated by this, we propose methods to impute missing daily outcomes in this paper. Specifically, we define a two-level missing pattern for clinical trials with daily patient-reported outcomes, and propose two-level methods to impute missing data at daily base. Other than the standard methods by multiple imputations, we derive analytic formulas for the proposed two-level methods to reduce computational intensity and improve the estimates of variances. The proposed two-level methods provide more powerful approaches to estimate the treatment difference compared to the conventional cycle-level methods, which are evaluated by theoretical development and simulation studies. In addition, the methods are applied to the motivating phase 3 trial evaluating a treatment for insomnia with daily patient-reported outcomes.

The assessment and management of insomnia: an update

Insomnia poses significant challenges to public health. It is a common condition associated with marked impairment in function and quality of life, psychiatric and physical morbidity, and accidents. As such, it is important that effective treatment is provided in clinical practice. To this end, this paper reviews critical aspects of the assessment of insomnia and the available treatment options. These options include both non-medication treatments, most notably cognitive behavioral therapy for insomnia, and a variety of pharmacologic therapies such as benzodiazepines, "z-drugs", melatonin receptor agonists, selective histamine H1 antagonists, orexin antagonists, antidepressants, antipsychotics, anticonvulsants, and non-selective antihistamines. A review of the available research indicates that rigorous double-blind, randomized, controlled trials are lacking for some of the most commonly administered insomnia therapies. However, there are an array of interventions which have been demonstrated to have therapeutic effects in insomnia in trials with the above features, and whose risk/benefit profiles have been well characterized. These interventions can form the basis for systematic, evidence-based treatment of insomnia in clinical practice. We review this evidence base and highlight areas where more studies are needed, with the aim of providing a resource for improving the clinical management of the many patients with insomnia.

Safety profile and clinical course of patients with insomnia administered suvorexant by initial treatment status in a post-marketing survey

Objectives: Suvorexant is a dual orexin receptor antagonist used for treating insomnia. The authors elucidated the safety profiles and clinical course of insomnia therapy with suvorexant under different initial treatment status seen in daily routine practice. Methods: Subgroup analysis of a post-marketing survey (PMS; 2015-2017) divided patients based on their initial treatment status with suvorexant into 'hypnotic-naïve (Group N)', 'switching from a prior sleep medication (Group S),' 'add-on therapy (Group A),' and 'others (Group O).' Results: Among 3248 patients analyzed in the PMS, the number of patients in Groups N, S, A, and O was 1946 (59.9%), 703 (21.6%), 536 (16.5%), and 63 (1.9%), respectively. The incidence of insomnia-related adverse drug reactions (ADRs) in Group S (5.3%) tended to be higher than that in Groups N (0.46%) and A (1.5%). Discontinuation rate due to an inadequate effect at 6 months in Group S (14.9%) tended to be higher than that in Groups N (9.6%) and A (10.4%). Conclusion: The results suggest that initiating suvorexant treatment after switching from other insomnia medication must require careful monitoring of insomnia-related ADRs, which might be due to abrupt discontinuation of the prior insomnia medication use.

Sleep modulating agents

Sleep and wake are two fundamental states of human existence. Conditions such as insomnia and hypersomnia can have profound negative effects on human health. Many pharmacological interventions impacting sleep and wake are available or are under development. This brief digest surveys early approaches to sleep modulation and highlights recent developments in sleep modulating agents.

British Association for Psychopharmacology consensus statement on evidence-based treatment of insomnia, parasomnias and circadian rhythm disorders: An update

This British Association for Psychopharmacology guideline replaces the original version published in 2010, and contains updated information and recommendations. A consensus meeting was held in London in October 2017 attended by recognised experts and advocates in the field. They were asked to provide a review of the literature and identification of the standard of evidence in their area, with an emphasis on meta-analyses, systematic reviews and randomised controlled trials where available, plus updates on current clinical practice. Each presentation was followed by discussion, aiming to reach consensus where the evidence and/or clinical experience was considered adequate, or otherwise to flag the area as a direction for future research. A draft of the proceedings was circulated to all speakers for comments, which were incorporated into the final statement.

Sleep Pharmacogenetics: The Promise of Precision Medicine

Pharmacogenetics is the branch of personalized medicine concerned with the variability in drug response occurring because of heredity. Advances in genetics research, and decreasing costs of gene sequencing, are promoting tremendous growth in pharmacogenetics in all areas of medicine, including sleep medicine. This article reviews the body of research indicating that there are genetic variations that affect the therapeutic actions and adverse effects of agents used for the treatment of sleep disorders to show the potential of pharmacogenetics to improve the clinical practice of sleep medicine.

Suvorexant (Belsomra® Tablets 10, 15, and 20 mg): Japanese Drug-Use Results Survey

BACKGROUND

We report on the results of a Japanese postmarketing drug-use survey of suvorexant (Belsomra^®) tablets.

METHODS

A survey with a ≤ 6-month observation period after the start of administration was conducted, targeting insomnia patients who were treated with suvorexant for the first time in Japan. Information on the safety and efficacy of the drug product was collected. The evaluation period was July 21, 2015-August 12, 2017, and the target number of patients was 3428.

RESULTS

The mean administration period for the safety analysis population of 3248 patients was 113 days. At 6 months after the start of treatment, 48.6% (1577/3248) of the patients had been continually receiving treatment, and 51.4% (1671/3248) of the patients discontinued/dropped out of treatment before 6 months. Among the patients who discontinued/dropped out of the treatment, more than 30% discontinued due to improvement. The mean treatment duration for those who had discontinued treatment for this reason was 62 days. The incidence rate of adverse drug reactions among those in the safety analysis population was 9.7%, and the common adverse drug reactions were somnolence (3.6%), insomnia (1.2%), dizziness (1.1%), and nightmare (0.8%), all of which are described in the product label. No additional noteworthy events were observed. In 2439 patients with a final overall global assessment of sleep judged by physicians, the 'improved' rate was 74.0%. Among 2424 patients who provided a final overall global assessment, the improvement rate was 73.2%, which was comparable with the improvement rate judged by physicians. Regarding clinical effects (based on patient diary data or physician's assessment), reduction in median sleep latency and increase in median total sleep time (reduction from 60 to 50 min and increase from 300 to 360 min compared with baseline, respectively) were observed at 1 week after the start of treatment and onwards, and the effect was maintained after the start of treatment for 6 months. A similar effect was observed irrespective of age groups or reasons for using suvorexant.

CONCLUSION

This survey was an exploratory observational study without a control group; the interpretation of results may require the consideration of factors that may have caused bias in the results, such as demographic characteristics and effects of other drugs. However, the results suggest that suvorexant can be a useful drug in daily clinical practice for treating insomnia.

Single-use suvorexant for treating insomnia during overnight polysomnography in patients with suspected obstructive sleep apnea: a single-center experience

Purpose

Although patients with suspected obstructive sleep apnea (OSA) might suffer difficulty in falling asleep during overnight polysomnography (PSG), standard hypnotics to obtain sleep during PSG have not been established. The aim of this study was to investigate the safety and efficacy of a new hypnotic agent, suvorexant, a dual orexin receptor antagonist, for insomnia in suspected OSA patients during in-laboratory PSG.

Patients and methods

An observational study was conducted during PSG for 149 patients with suspected OSA who had no insomnia at home. Patients with difficulty in falling asleep during PSG were optionally permitted to take single-use suvorexant. Patients with residual severe insomnia (>1 hour) after taking suvorexant were permitted to take an add-on use zolpidem. Clinical data and sleep questionnaire results were analyzed between a no insomnia group (without hypnotics) and an insomnia group (treated with suvorexant).

Results

Among 84 patients who experienced insomnia during PSG and required hypnotics (the insomnia group; treated with suvorexant), 44 (52.4%) achieved sufficient subjective sleep with single-use of suvorexant, while the other 40 (47.6%) required suvorexant plus zolpidem. An apnea hypopnea index (AHI) of ≥5 was observed in 144 out of 149 patients with predominantly obstructive respiratory events. Among those patients, 70.8% in the no insomnia group and 63.1% in the insomnia group had severe OSA. Regarding both subjective sleep time and morning mood, significant differences between the no insomnia group and the insomnia group were not observed. No patient taking suvorexant had an adverse event, such as delirium or falling.

Conclusion

Single-use suvorexant seems to be a safe and effective (but mild) hypnotic agent for suspected OSA patients with insomnia during in-laboratory PSG.

Effect of CYP3A Inhibition and Induction on the Pharmacokinetics of Suvorexant: Two Phase I, Open-Label, Fixed-Sequence Trials in Healthy Subjects

BACKGROUND AND OBJECTIVES

Suvorexant is an orexin receptor antagonist indicated for the treatment of insomnia, characterized by difficulties with sleep onset and/or sleep maintenance. As suvorexant is metabolized primarily by Cytochrome P450 3A (CYP3A), and its pharmacokinetics may be affected by CYP3A modulators, the effects of CYP3A inhibitors (ketoconazole or diltiazem) or an inducer (rifampin [rifampicin]) on the pharmacokinetics, safety, and tolerability of suvorexant were investigated.

METHODS

In two Phase I, open-label, fixed-sequence trials (Studies P008 and P038), healthy subjects received a single oral dose of suvorexant followed by co-administration with multiple once-daily doses of strong/moderate CYP3A inhibitors (ketoconazole/diltiazem) or a strong CYP3A inducer (rifampin). Treatments were administered in the morning: suvorexant 4 mg with ketoconazole 400 mg (Study P008; N = 10), suvorexant 20 mg with diltiazem 240 mg (Study P038; N = 20), and suvorexant 40 mg with rifampin 600 mg (Study P038; N = 10). Area under the plasma concentration-time curve from time zero to infinity (AUC_0-∞), maximum plasma concentration (C_max), half-life (t_½), and time to C_max (t_max) were derived from plasma concentrations of suvorexant collected at prespecified time points up to 10 days following CYP3A inhibitor/inducer co-administration. Adverse events (AEs) were recorded.

RESULTS

Co-administration with ketoconazole resulted in increased exposure to suvorexant [AUC_0-∞: geometric mean ratio (GMR); 90% confidence interval (CI) 2.79 (2.35, 3.31)] while co-administration with diltiazem resulted in a lesser effect [GMR (90% CI): 2.05 (1.82, 2.30)]. Co-administration with rifampin led to a marked decrease (88%) in suvorexant exposure. Consistent with morning administration and known suvorexant pharmacology, somnolence was the most frequently reported AE.

CONCLUSIONS

These results are consistent with expectations that strong CYP3A inhibitors and inducers exert marked effects on suvorexant pharmacokinetics. In the context of a limited sample size, single suvorexant doses were generally well tolerated in healthy subjects when co-administered with/without a CYP3A inhibitor/inducer.

Depression in sleep disturbance: A review on a bidirectional relationship, mechanisms and treatment

Sleep disturbance is the most prominent symptom in depressive patients and was formerly regarded as a main secondary manifestation of depression. However, many longitudinal studies have identified insomnia as an independent risk factor for the development of emerging or recurrent depression among young, middle‐aged and older adults. This bidirectional association between sleep disturbance and depression has created a new perspective that sleep problems are no longer an epiphenomenon of depression but a predictive prodromal symptom. In this review, we highlight the treatment of sleep disturbance before, during and after depression, which probably plays an important role in improving outcomes and preventing the recurrence of depression. In clinical practice, pharmacological therapies, including hypnotics and antidepressants, and non‐pharmacological therapies are typically applied. A better understanding of the pathophysiological mechanisms between sleep disturbance and depression can help psychiatrists better manage this comorbidity.

Drugs for Insomnia beyond Benzodiazepines: Pharmacology, Clinical Applications, and Discovery

Although the GABAergic benzodiazepines (BZDs) and Z-drugs (zolpidem, zopiclone, and zaleplon) are FDA-approved for insomnia disorders with a strong evidence base, they have many side effects, including cognitive impairment, tolerance, rebound insomnia upon discontinuation, car accidents/falls, abuse, and dependence liability. Consequently, the clinical use of off-label drugs and novel drugs that do not target the GABAergic system is increasing. The purpose of this review is to analyze the neurobiological and clinical evidence of pharmacological treatments of insomnia, excluding the BZDs and Z-drugs. We analyzed the melatonergic agonist drugs, agomelatine, prolonged-release melatonin, ramelteon, and tasimelteon; the dual orexin receptor antagonist suvorexant; the modulators of the α₂δ subunit of voltage-sensitive calcium channels, gabapentin and pregabalin; the H₁ antagonist, low-dose doxepin; and the histamine and serotonin receptor antagonists, amitriptyline, mirtazapine, trazodone, olanzapine, and quetiapine. The pharmacology and mechanism of action of these treatments and the evidence-base for the use of these drugs in clinical practice is outlined along with novel pipelines. There is evidence to recommend suvorexant and low-dose doxepin for sleep maintenance insomnia; there is also sufficient evidence to recommend ramelteon for sleep onset insomnia. Although there is limited evidence for the use of the quetiapine, trazodone, mirtazapine, amitriptyline, pregabalin, gabapentin, agomelatine, and olanzapine as treatments for insomnia disorder, these drugs may improve sleep while successfully treating comorbid disorders, with a different side effect profile than the BZDs and Z-drugs. The unique mechanism of action of each drug allows for a more personalized and targeted medical management of insomnia.

Orexin as a modulator of fear-related behavior: Hypothalamic control of noradrenaline circuit

Fear is an important physiological function for survival. It appears when animals or humans are confronted with an environmental threat. The amygdala has been shown to play a highly important role in emergence of fear. Hypothalamic orexin neurons are activated by fearful stimuli to evoke a 'defense reaction' with an increase in arousal level and sympathetic outflow to deal with the imminent danger. However, how this system contributes to the emergence of fear-related behavior is not well understood. Orexin neurons in the hypothalamus send excitatory innervations to noradrenergic neurons in the locus coeruleus (NA^LC) which express orexin receptor 1 (OX1R) and send projections to the lateral amygdala (LA). Inhibition of this di-synaptic orexin → NA^LC → LA pathway by pharmacological or opto/chemogenetic methods reduces cue-induced fear expression. Excitatory manipulation of this pathway induces freezing, a fear-related behavior that only occurs when the environment contains some elements suggestive of danger. Although, fear memory helps animals respond to a context or cue previously paired with an aversive stimulus, fear-related behavior is sometimes evoked even in a distinct context containing some similar elements, which is known as fear generalization. Our recent observation suggests that the orexin → NA^LC → LA pathway might contribute to this response. This review focuses on recent advances regarding the role of hypothalamic orexin neurons in behavioral fear expression. We also discuss the potential effectiveness of orexin receptor antagonists for treating excessive fear response or overgeneralization seen in anxiety disorder and post-traumatic stress disorder (PTSD).

Insomnia in Elderly Patients: Recommendations for Pharmacological Management

Chronic insomnia affects 57% of the elderly in the United States, with impairment of quality of life, function, and health. Chronic insomnia burdens society with billions of dollars in direct and indirect costs of care. The main modalities in the treatment of insomnia in the elderly are psychological/behavioral therapies, pharmacological treatment, or a combination of both. Various specialty societies view psychological/behavioral therapies as the initial treatment intervention. Pharmacotherapy plays an adjunctive role when insomnia symptoms persist or when patients are unable to pursue cognitive behavioral therapies. Current drugs for insomnia fall into different classes: orexin agonists, histamine receptor antagonists, non-benzodiazepine gamma aminobutyric acid receptor agonists, and benzodiazepines. This review focuses on Food and Drug Administration (FDA)-approved drugs for insomnia, including suvorexant, low-dose doxepin, Z-drugs (eszopiclone, zolpidem, zaleplon), benzodiazepines (triazolam, temazepam), and ramelteon. We review the indications, dosing, efficacy, benefits, and harms of these drugs in the elderly, and discuss data on drugs that are commonly used off-label to treat insomnia, and those that are in clinical development. The choice of a hypnotic agent in the elderly is symptom-based. Ramelteon or short-acting Z-drugs can treat sleep-onset insomnia. Suvorexant or low-dose doxepin can improve sleep maintenance. Eszopiclone or zolpidem extended release can be utilized for both sleep onset and sleep maintenance. Low-dose zolpidem sublingual tablets or zaleplon can alleviate middle-of-the-night awakenings. Benzodiazepines should not be used routinely. Trazodone, a commonly used off-label drug for insomnia, improves sleep quality and sleep continuity but carries significant risks. Tiagabine, sometimes used off-label for insomnia, is not effective and should not be utilized. Non-FDA-approved hypnotic agents that are commonly used include melatonin, diphenhydramine, tryptophan, and valerian, despite limited data on benefits and harms. Melatonin slightly improves sleep onset and sleep duration, but product quality and efficacy may vary. Tryptophan decreases sleep onset in adults, but data in the elderly are not available. Valerian is relatively safe but has equivocal benefits on sleep quality. Phase II studies of dual orexin receptor antagonists (almorexant, lemborexant, and filorexant) have shown some improvement in sleep maintenance and sleep continuity. Piromelatine may improve sleep maintenance. Histamine receptor inverse agonists (APD-125, eplivanserin, and LY2624803) improve slow-wave sleep but, for various reasons, the drug companies withdrew their products.

A sleeping giant: Suvorexant for the treatment of alcohol use disorder?

There are currently 3 FDA approved treatments for alcohol use disorder (AUD) in the USA, opioid receptor antagonists such as naltrexone, disulfiram and acamprosate. To date, these have been largely inadequate at preventing relapse at a population level and this may be because they only target certain aspects of AUD. Recently, suvorexant, a dual orexin receptor antagonist, has been FDA approved for the treatment of insomnia. Importantly, sleep disruptions occur during both acute and prolonged alcohol exposure and sleep deprivation is a potent factor promoting relapse to alcohol use. In this mini review article, we explore the therapeutic potential of suvorexant for the treatment of AUD. In particular, we highlight that in addition to altering the motivational properties of alcohol, suvorexant may also address key physiological components associated with alcohol withdrawal and abstinence, such as sleep disruptions, which should in turn help reduce or prevent relapse.

[Sleep and its' disturbanses in chronic obstructive pulmonary disease]

Physiology of breathing during sleep predisposes to the development or worsening of the respiratory disorders in patients with chronic obstructive pulmonary disease (COPD) even if waking respiratory function remains relatively normal. Physicians, who assess patient's state only during the day, in some cases can underestimate this problem. Respiratory abnormalities can provoke insomnia, which additionally affects patient's quality of life. Supplemental oxygen and pressure support ventilation improve blood gases during sleep, but in many cases, insomnia persists. In many cases, such patients need the treatment with hypnotics. Widely used drugs in insomnia are benzodiazepines. They are rather effective but can cause respiratory depression and respiratory failure in patients with COPD. Z-hypnotics are comparable to classical benzodiazepines but much more safe and rarely worsen respiratory parameters. Melatonin and melatonin receptor agonists, antihistamines, antidepressants and neuroleptics can be effective in some patients with insomnia, but insufficient data about their safety in case of respiratory pathology restrict the use of these drugs in patients with COPD. The orexin receptor antagonist suvorexant is a novel hypnotic with the potential benefits for patients with COPD because it strongly improves sleep but does not depress respiration and has a minimal negative impact on daytime cognitive function.

Orexins, Sleep, and Blood Pressure

Purpose of Review

The aim of this review was to summarize collected data on the role of orexin and orexin neurons in the control of sleep and blood pressure.

Recent Findings

Although orexins (hypocretins) have been known for only 20 years, an impressive amount of data is now available regarding their physiological role. Hypothalamic orexin neurons are responsible for the control of food intake and energy expenditure, motivation, circadian rhythm of sleep and wake, memory, cognitive functions, and the cardiovascular system. Multiple studies show that orexinergic stimulation results in increased blood pressure and heart rate and that this effect may be efficiently attenuated by orexinergic antagonism. Increased activity of orexinergic neurons is also observed in animal models of hypertension.

Summary

Pharmacological intervention in the orexinergic system is now one of the therapeutic possibilities in insomnia. Although the role of orexin in the control of blood pressure is well described, we are still lacking clinical evidence that this is a possibility for a new approach in the treatment of cardiovascular diseases.

Cost-effectiveness analysis of suvorexant for the treatment of Japanese elderly patients with chronic insomnia in a virtual cohort

AIMS

This study assessed the cost-effectiveness of the orexin receptor antagonist suvorexant against zolpidem, the most widely used hypnotic benzodiazepine receptor agonist in Japan. To this end, a model was used that factored in insomnia and the risk for hip fractures, which have devastating effects on the elderly.

METHODS

Data were derived from published papers. The target population was a virtual cohort of elderly patients (≥65 years) with insomnia residing in Japan. Cost-effectiveness was evaluated using quality-adjusted life years (QALYs) and the incremental cost-effectiveness ratio as effectiveness measures. The investigators assumed the perspective of healthcare payers.

RESULTS

In the base-case analysis, suvorexant was cost-saving (suvorexant: $252.3, zolpidem: $328.7) and had higher QALYs gained (suvorexant: 0.0641, zolpidem: 0.0635) for elderly Japanese patients with insomnia compared with zolpidem, indicating that suvorexant was dominant. In the sensitivity analysis, the outcome changed from dominant to dominated due to the relative risk for hip fractures associated with suvorexant. However, when the other parameters were varied from the lower to the upper limits of their ranges, suvorexant remained dominant compared to zolpidem.

LIMITATIONS

The relative risk for hip fractures for suvorexant used in the model was based on data from pre-approval clinical trials. More precise data may be needed.

CONCLUSIONS

Suvorexant seemed to be more cost-effective than the alternative zolpidem. The findings suggested that suvorexant might be a viable alternative to zolpidem for elderly patients with insomnia. A sensitivity analysis showed that outcome varied depending on the relative risk for hip fractures associated with suvorexant. Further investigations may be needed for more precise results.

How representative are insomnia clinical trials?

OBJECTIVES

To address the question of how representative subjects studied in hypnotic clinical trials are of the broader insomnia population, this study assessed initial contact rates and reasons for inclusion and exclusion during recruitment to an efficacy trial and to a safety trial of Food & Drug Administration (FDA) approved hypnotics.

METHODS

Otherwise heathy persons meeting Diagnostic Statistical Manual, Fourth Edition, Revised (DSM-IVR) criteria for insomnia were recruited. In one study, persons 32-65 yrs, were invited to a 12 month trial of nightly use of zolpidem or placebo. In the other, persons 21-64 yrs with driver's licenses were recruited to test the effects of a hypnotic on live on-the-road driving ability. In both studies screening was conducted through an initial telephone interview followed by a clinic visit.

RESULTS

In the United States (US) study 13% (n = 410) of 3180 initial contacts and in the Netherlands (NL) study 67% (n = 53) of the 79 initial contacts proceeded to the clinic visit. Of those at clinic 25% of US and 37% of NL participants failed to meet additional insomnia criteria. Mental health exclusions accounted for 24% of US and 23% of NL participants and medical problems accounted for 23% of US and 9% NL exclusions. Finally 20% of US and 26% of NL participants were excluded for drug use/abuse histories. After all screening 4% of the initial US contacts and 0% of the NL contacts entered the study.

CONCLUSIONS

These data suggest persons entering insomnia hypnotic clinical trials are a highly selected sample that is unlikely to be representative of the broad insomnia population or the population of potential medication users.

A randomized Phase 2 study to evaluate the orexin-2 receptor antagonist seltorexant in individuals with insomnia without psychiatric comorbidity

BACKGROUND

Seltorexant is a potent and selective antagonist of the orexin-2 receptor that is being developed for the treatment of insomnia and major depressive disorder.

AIMS

The primary objective was to investigate the effect of seltorexant on sleep efficiency after single and multiple dose administration in subjects with insomnia disorder without psychiatric comorbidity. Secondary objectives included evaluation of total sleep time, latency to persistent sleep, and wake after sleep onset. Subjects received 40 mg of seltorexant for five days during Period 1 and placebo during Period 2 or vice versa in this randomized, two-way crossover study. Objective sleep parameters were evaluated by polysomnography over 8 h on Day 1/2 (single dose) and on Day 5/6 (multiple doses). Subjective sleep parameters were assessed by questionnaires.

RESULTS

Twenty-seven subjects completed the study. The mean changes in sleep efficiency (% (SD)) of seltorexant from placebo at Day 1/2 were 5.8 (9.2), and 7.9 (9.8) at Day 5/6 ( p < 0.001 at both time points); in total sleep time (min (SD)) 27.7 (44.3) and 37.9 (47.1), respectively; in latency to persistent sleep (min (SD)) -18.8 (21.3) and -29.9 (27.7), respectively; and in wake after sleep onset (min (SD)) -11.1 (36.4) and -11.3 (46.5). The most common adverse events were headache and somnolence.

CONCLUSIONS

Sleep efficiency was increased with seltorexant treatment compared with placebo. Treatment with seltorexant resulted in a prolonged total sleep time, shorter latency to persistent sleep and wake after sleep onset. There were no unexpected safety findings.

Assessment of Switching to Suvorexant versus the Use of Add-on Suvorexant in Combination with Benzodiazepine Receptor Agonists in Insomnia Patients: A Retrospective Study

Objective

Suvorexant is a novel hypnotic drug that does not interact with the conventional γ-aminobutyric acid (GABA)-A receptor. We investigated the method by which suvorexant was introduced in insomnia patients who were taking benzodiazepine receptor agonists (BzRA).

Methods

This was a retrospective study. We extracted clinical data for patients who were prescribed suvorexant and were already using BzRA. The patients were assigned to two groups, the switching and add-on groups. We assessed the suvorexant discontinuation rate at one month after the prescription of the drug.

Results

One hundred and nineteen patients were assigned to the switching group, and 109 were assigned to the add-on group. The add-on group exhibited a significantly higher all-cause discontinuation rate than the switching group (odds ratio, 2.7; 95% confidence interval, 1.5 to 5.0; adjusted p<0.001). Intolerability was a significantly stronger risk factor for suvorexant discontinuation in the add-on group (22.0% vs. 7.6%, p<0.002), and the most common adverse effect was oversedation.

Conclusion

Our results show that the add-on of suvorexant increases the frequency of oversedation compared with switching in insomnia patients that are taking BzRA. However, this was only a preliminary retrospective study, and further studies will be required to confirm our findings.

A novel forehead temperature-regulating device for insomnia: a randomized clinical trial

Study Objectives

Insomnia is one of the most common disorders in the general population. Hypnotic medications are efficacious, but their use is limited by adverse events (AEs). This study evaluated the safety and efficacy of a novel forehead temperature-regulating device that delivers frontal cerebral thermal therapy (maintained at 14-16°C, equivalent to 57-61°F) for the treatment of insomnia.

Methods

This was a prospective, randomized controlled trial involving two nights of therapy in 106 adults diagnosed with insomnia. The main outcome measures included latency to persistent sleep and sleep efficiency derived from polysomnographic (PSG) recordings and frequency and severity of AEs.

Results

The safety profile was comparable to sham treatment. Statistically significant differences were not found in the two a priori co-primary endpoint measures absolute latency to persistent sleep (p = 0.092) or absolute sleep efficiency. Frontal cerebral thermal therapy produced improvements over sham in other convergent measures of sleep latency including relative changes from baseline in latency to persistent sleep (p = 0.013), the latency to stage 1 NREM sleep (p = 0.006), the latency to stage 2 NREM sleep (p = 0.002), a trend for the latency to stage 3 NREM sleep (p = 0.055), and an increase in the minutes of sleep during the first hour of the night (p = 0.024).

Conclusions

Two-night frontal cerebral thermal therapy produced improvements in PSG measures of insomnia patients' ability to fall asleep and had a benign safety profile. Further studies are warranted to determine the role of this therapy in the longer-term management of insomnia.

Trial Registration

clinicaltrials.gov Identifier: NCT01966211.

DEC2 modulates orexin expression and regulates sleep

Adequate sleep is essential for physical and mental health. We previously identified a missense mutation in the human DEC2 gene (BHLHE41) leading to the familial natural short sleep behavioral trait. DEC2 is a transcription factor regulating the circadian clock in mammals, although its role in sleep regulation has been unclear. Here we report that prepro-orexin, also known as hypocretin (Hcrt), gene expression is increased in the mouse model expressing the mutant hDEC2 transgene (hDEC2-P384R). Prepro-orexin encodes a precursor protein of a neuropeptide producing orexin A and B (hcrt1 and hcrt2), which is enriched in the hypothalamus and regulates maintenance of arousal. In cell culture, DEC2 suppressed prepro-orexin promoter-luc (ore-luc) expression through cis-acting E-box elements. The mutant DEC2 has less repressor activity than WT-DEC2, resulting in increased orexin expression. DEC2-binding affinity for the prepro-orexin gene promoter is decreased by the P384R mutation, likely due to weakened interaction with other transcription factors. In vivo, the decreased immobility time of the mutant transgenic mice is attenuated by an orexin receptor antagonist. Our results suggested that DEC2 regulates sleep/wake duration, at least in part, by modulating the neuropeptide hormone orexin.

Suvorexant for insomnia in older adults: a perspective review

The aim of this review was to identify published randomized control trials (RCTs) that evaluated the efficacy and tolerability of suvorexant for the treatment of insomnia among older adults (≥65 years). A literature search was conducted of PubMed, MEDLINE, EMBASE, PsycINFO and Cochrane collaboration databases for RCTs in any language evaluating suvorexant for the treatment of insomnia in older adults. Additionally, references of full-text articles that were included in this review were searched for further studies. Data from three RCTs of suvorexant were included in this review. All the three studies fulfilled the criteria for being of good quality based on the items listed by the Center for Evidence Based Medicine (CEBM) for the assessment of RCTs. None of the three studies were conducted exclusively among older adults. However, they also included older individuals diagnosed with primary insomnia. These studies included a total of 1298 participants aged ≥65 years in age. Trial durations ranged from 3 months to 1 year. Available data from these studies indicate that suvorexant improves multiple subjective and polysomnographic sleep parameters for sleep onset and maintenance among older individuals with a diagnosis of primary insomnia and is generally well tolerated. Current evidence, although limited, indicates that suvorexant benefits older adults with primary insomnia and is generally well tolerated.

Suvorexant: scientifically interesting, utility uncertain

OBJECTIVE

Suvorexant, a new hypnotic, is indicated for the treatment of insomnia characterized by difficulties with sleep onset and/or sleep maintenance, and is used long-term. This paper will briefly review suvorexant.

RESULTS

Orexin is a hypothalamic peptide which promotes wakefulness. By blocking orexin receptors, suvorexant induces sleep. Peaking 2 h after ingestion, it has a half-life of 12 h and is hepatically metabolized mainly by CYP3A. Kinetics are not affected by age but concentrations are higher in females and obese patients. There may be interactions with benzodiazepines, antidepressants and antipsychotics. Suvorexant is available in 15 mg and 20 mg doses at which benefits are moderate: after three months' treatment users fell asleep 6 min faster and slept 16 min longer than those on placebo. Studies with 40 mg showed greater benefits but more side effects: next day somnolence, fatigue, xerostomia and peripheral oedema. Hallucinations, sleep paralysis and somnambulism occur rarely. Tolerance, withdrawal and rebound do not generally occur at recommended doses.

CONCLUSION

Suvorexant has not been trialled against other hypnotics, is expensive and its utility for insomnia in patients with psychiatric disorders is unknown. Currently, use of suvorexant could be considered where more established treatments are inappropriate.

The Discovery of Suvorexant, the First Orexin Receptor Drug for Insomnia

Historically, pharmacological therapies have used mechanisms such as γ-aminobutyric acid A (GABA_A) receptor potentiation to drive sleep through broad suppression of central nervous system activity. With the discovery of orexin signaling loss as the etiology underlying narcolepsy, a disorder associated with hypersomnolence, orexin antagonism emerged as an alternative approach to attenuate orexin-induced wakefulness more selectively. Dual orexin receptor antagonists (DORAs) block the activity of orexin 1 and 2 receptors to both reduce the threshold to transition into sleep and attenuate orexin-mediated arousal. Among DORAs evaluated clinically, suvorexant has pharmacokinetic properties engineered for a plasma half-life appropriate for rapid sleep onset and maintenance at low to moderate doses. Unlike GABA_A receptor modulators, DORAs promote both non-rapid eye movement (NREM) and REM sleep, do not disrupt sleep stage-specific quantitative electroencephalogram spectral profiles, and allow somnolence indistinct from normal sleep. The preservation of cognitive performance and the ability to arouse to salient stimuli after DORA administration suggest further advantages over historical therapies.

Lemborexant, A Dual Orexin Receptor Antagonist (DORA) for the Treatment of Insomnia Disorder: Results From a Bayesian, Adaptive, Randomized, Double-Blind, Placebo-Controlled Study

STUDY OBJECTIVES

To identify dose(s) of lemborexant that maximize insomnia treatment efficacy while minimizing next-morning residual sleepiness and evaluate lemborexant effects on polysomnography (PSG) measures (sleep efficiency [SE], latency to persistent sleep [LPS], and wake after sleep onset [WASO]) at the beginning and end of treatment.

METHODS

Adults and elderly subjects with insomnia disorder per the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition were enrolled in a multicenter, randomized, double-blind, placebo-controlled, Bayesian, adaptive, parallel-group study, receiving lemborexant (1, 2.5, 5, 10, 15, 25 mg) or placebo for 15 nights. Efficacy assessments included a utility function that combined efficacy (SE) and safety (residual morning sleepiness as measured by Karolinska Sleepiness Scale [KSS]), PSG measures, and sleep diary. Safety assessments included KSS, Digit Symbol Substitution Test, computerized reaction time tests, and adverse events (AEs).

RESULTS

A total of 616 subjects were screened; 291 were randomized. Baseline characteristics were similar between lemborexant groups and placebo (∼63% female, median age: 49.0 years). The study was stopped for early success after the fifth interim analysis when the 15-mg dose met utility index/KSS criteria for success; 3 other doses also met the criteria. Compared with placebo, subjects showed significant improvements in SE, subjective SE, LPS, and subjective sleep onset latency at the beginning and end of treatment for lemborexant doses ≥ 5 mg (P < .05). WASO and subjective WASO showed numerically greater improvements for doses > 1 mg. AEs, mostly mild to moderate, included dose-related somnolence.

CONCLUSIONS

Lemborexant doses ranging from 2.5-10 mg provided efficacy for the treatment of insomnia while minimizing next-morning residual sleepiness.

CLINICAL TRIAL REGISTRATION

Title: A Multicenter, Randomized, Double-blind, Placebo-controlled, Parallel-group, Bayesian Adaptive Randomization Design, Dose Response Study of the Efficacy of E2006 in Adults and Elderly Subjects With Chronic Insomnia; URL: https://clinicaltrials.gov/ct2/show/NCT01995838; Identifier: NCT01995838.

Suvorexant for the Treatment of Insomnia in Adolescents

OBJECTIVES

Suvorexant is the first dual orexin receptor antagonist for treating insomnia. This study aimed to evaluate the tolerability, efficacy, and safety of suvorexant on insomnia in adolescents.

METHODS

Thirty patients (8 male and 22 female; mean standard deviation age: 15.7 ± 2.4 years; range: 10-20) with insomnia were administered suvorexant. Clinical background, persistence rate, the Clinical Global Impression (CGI), and the Athens Insomnia Scale (AIS) were compared between patients who continued and discontinued suvorexant treatment.

RESULTS

Seventeen patients (56.7%) successfully continued taking suvorexant. Among the 13 patients who did not continue treatment, 5 patients were lost to follow-up. Of the remaining eight who did not continue treatment, four decided to discontinue of their own accord, two decided to discontinue due to lack of effectiveness, and two decided to discontinue due to adverse reaction, namely abnormal dreams. Among patients who completed the study, CGI significantly decreased from 3.6 ± 0.8 to 3.1 ± 0.9 (p = 0.014). The score of sleep quality in AIS was significantly higher among the patients who discontinued suvorexant than those who continued suvorexant (p = 0.02).

CONCLUSION

Our results indicate that suvorexant could be considered a treatment option for adolescents.

Adverse reaction with suvorexant for insomnia: acute worsening of depression with emergence of suicidal thoughts

A 59-year-old woman on daily peritoneal dialysis for end-stage renal failure received care at an outpatient psychiatric clinic for her diagnoses that include major depressive disorder, generalised anxiety disorder and insomnia disorder. Although there was partial improvement in the patient's mood and anxiety symptoms with antidepressant treatment, insomnia remained a persistent complaint despite adequate trials of different sleep medications. The novel hypnotic, suvorexant (Belsomra, Merck & Co.) was then initiated at the recommended bedtime dose of 10 mg and was followed by a 15 mg dose the following night. Within an hour after taking her second suvorexant dose, the severity of patient's depression symptoms worsened and was accompanied by new onset of suicidal thoughts.

Statistical planning in confirmatory clinical trials with multiple treatment groups, multiple visits, and multiple endpoints

Multiplicity issues can be multidimensional: A confirmatory clinical trial may be designed to have efficacy assessed with two or more primary endpoints, for multiple dose groups, and at several post-baseline visits. Controlling for multiplicity in this situation is challenging because there can be a hierarchy with respect to some but not all measurements. If the higher dose is considered more efficacious, multiplicity approach may evaluate the higher dose with higher priority through a fixed sequential testing framework for dose assessments in combination with a Hochberg approach for endpoints. The lower dose is only assessed when the higher dose has significant results, which reduces the power for detecting signals in the lower dose group. However, in some instances the higher dose may associate with tolerability or safety concerns that preclude regulatory approval. A real confirmatory clinical trial with such challenges is provided as an illustrative example. We discuss closed testing procedures based on multi-way averages of comparisons for this complex multiplicity situation through illustrative case analyses and a simulation study. Such strategies manage the higher dose and the lower dose with equal priority, and they enable evaluation of the multiple endpoints at multiple visits collectively with power being reasonably high.

Effectiveness of Benzodiazepine Receptor Agonists in the Treatment of Insomnia: An Examination of Response and Remission Rates

Study objectives

To examine the real-world effectiveness of benzodiazepine receptor agonists (BzRAs) by quantifying response and remission rates in a clinical sample receiving chronic BzRA treatment for insomnia.

Methods

Participants were outpatients (N = 193; 72% female; 55.2 ± 11.1 year) who had an insomnia diagnosis per medical records, and who were taking a therapeutic dose of BzRA for their insomnia. Endpoints were nocturnal sleep disturbance and Insomnia Severity Index (ISI) scores. A reduction meeting the criterion for the minimally important difference in ISI scores (change ≥ 6) constituted "response"; "remission" was inferred when symptoms fell below the clinical cutoff (ISI < 11).

Results

Most participants (71%) used BzRAs at least 5 nights per week. Mean ISI scores were significantly lower (t = 22.31; p < .01) while on BzRAs than when untreated, but remained in the clinical range (mean = 11.0; standard deviation = 5.7). Although 76.7% responded to treatment, only 47.7% remitted. The majority (68.9%) of participants had a sleep-onset latency > 30 minutes and/or wake-time after sleep onset > 60 minutes while on BzRAs. After controlling for gender and insomnia severity when untreated, odds of insomnia persistence despite BzRA use were 2 times higher in patients with comorbid medical [odds ratio (OR) = 2.39; 95% confidence interval (CI) = 1.20% to 4.77%; p < .05] and psychiatric disorders (OR = 2.24; 95% CI = 1.21% to 4.13%; p < .05).

Conclusions

This is the first study to distinguish between response and remission in insomnia patients taking BzRAs. Findings suggest that while many insomnia patients respond to chronic BzRA treatment, most do not remit. Remission rates are particularly low for comorbid insomnia, the most prevalent phenotype of the disorder.

Orexin OX2 Receptor Antagonists as Sleep Aids

The discovery of the orexin system represents the single major progress in the sleep field of the last three to four decades. The two orexin peptides and their two receptors play a major role in arousal and sleep/wake cycles. Defects in the orexin system lead to narcolepsy with cataplexy in humans and dogs and can be experimentally reproduced in rodents. At least six orexin receptor antagonists have reached Phase II or Phase III clinical trials in insomnia, five of which are dual orexin receptor antagonists (DORAs) that target both OX1 and OX2 receptors (OX2Rs). All clinically tested DORAs induce and maintain sleep: suvorexant, recently registered in the USA and Japan for insomnia, represents the first hypnotic principle that acts in a completely different manner from the current standard medications. It is clear, however, that in the clinic, all DORAs promote sleep primarily by increasing rapid eye movement (REM) and are almost devoid of effects on slow-wave (SWS) sleep. At present, there is no consensus on whether the sole promotion of REM sleep has a negative impact in patients suffering from insomnia. However, sleep onset REM (SOREM), which has been documented with DORAs, is clearly an undesirable effect, especially for narcoleptic patients and also in fragile populations (e.g. elderly patients) where REM-associated loss of muscle tone may promote an elevated risk of falls. Debate thus remains as to the ideal orexin agent to achieve a balanced increase in REM and non-rapid eye movement (NREM) sleep. Here, we review the evidence that an OX2R antagonist should be at least equivalent, or perhaps superior, to a DORA for the treatment of insomnia. An OX2R antagonist may produce more balanced sleep than a DORA. Rodent sleep experiments show that the OX2R is the primary target of orexin receptor antagonists in sleep modulation. Furthermore, an OX2R antagonist should, in theory, have a lower narcoleptic/cataplexic potential. In the clinic, the situation remains equivocal, since OX2R antagonists are in early stages: MK-1064 has completed Phase I, and MIN202 is currently in clinical Phase II/III trials. However, data from insomnia patients have not yet been released. Promotional material suggests that balanced sleep is indeed induced by MIN-202, whereas in volunteers MK-1064 has been reported to act similarly to DORAs.

Suvorexant in Elderly Patients with Insomnia: Pooled Analyses of Data from Phase III Randomized Controlled Clinical Trials

OBJECTIVE

Suvorexant is an orexin receptor antagonist approved for treating insomnia at doses of 10-20 mg. Previously reported phase III results showed that suvorexant was effective and well-tolerated in a combined-age population (elderly and nonelderly adults). The present analysis evaluated the clinical profile of suvorexant specifically in the elderly.

METHODS

Prespecified subgroup analyses of pooled 3-month data from two (efficacy) and three (safety) randomized, double-blind, placebo-controlled, parallel-group trials. In each trial, elderly (≥65 years) patients with insomnia were randomized to suvorexant 30 mg, suvorexant 15 mg, and placebo. By design, fewer patients were randomized to 15 mg. Patient-reported and polysomnographic (subset of patients) sleep maintenance and onset endpoints were measured.

RESULTS

Suvorexant 30 mg (N = 319) was effective compared with placebo (N = 318) on patient-reported and polysomnographic sleep maintenance, and onset endpoints at Night 1 (polysomnographic endpoints)/Week 1 (patient-reported endpoints), Month 1, and Month 3. Suvorexant 15 mg (N = 202 treated) was also effective across these measures, although the onset effect was less evident at later time points. The percentages of patients discontinuing because of adverse events over 3 months were 6.4% for 30 mg (N = 627 treated), 3.5% for 15 mg (N = 202 treated), and 5.5% for placebo (N = 469 treated). Somnolence was the most common adverse event (8.8% for 30 mg, 5.4% for 15 mg, 3.2% for placebo).

CONCLUSION

Suvorexant generally improved sleep maintenance and onset over 3 months of nightly treatment and was well-tolerated in elderly patients with insomnia (clinicaltrials.gov; NCT01097616, NCT01097629, NCT01021813).

Phase II Proof-of-Concept Trial of the Orexin Receptor Antagonist Filorexant (MK-6096) in Patients with Major Depressive Disorder

BACKGROUND

We evaluated the orexin receptor antagonist filorexant (MK-6096) for treatment augmentation in patients with major depressive disorder.

METHODS

We conducted a 6-week, double-blind, placebo-controlled, parallel-group, Phase II, proof-of-concept study. Patients with major depressive disorder (partial responders to ongoing antidepressant therapy) were randomized 1:1 to once-daily oral filorexant 10 mg or matching placebo.

RESULTS

Due to enrollment challenges, the study was terminated early, resulting in insufficient statistical power to detect a prespecified treatment difference; of 326 patients planned, 129 (40%) were randomized and 128 took treatment. There was no statistically significant difference in the primary endpoint of change from baseline to week 6 in Montgomery Asberg Depression Rating Scale total score; the estimated treatment difference for filorexant-placebo was -0.7 (with negative values favoring filorexant) (P=.679). The most common adverse events were somnolence and suicidal ideation.

CONCLUSIONS

The interpretation of the results is limited by the enrollment, which was less than originally planned, but the available data do not suggest efficacy of orexin receptor antagonism with filorexant for the treatment of depression. (Clinical Trial Registry: clinicaltrials.gov: NCT01554176).

Clinical profile of suvorexant for the treatment of insomnia over 3 months in women and men: subgroup analysis of pooled phase-3 data

RATIONALE

Sex-related differences in the clinical profiles of some insomnia medications have been previously reported.

OBJECTIVE

To evaluate the clinical profile of suvorexant, a novel orexin receptor antagonist approved for treating insomnia at doses up to 20 mg, by sex subgroups.

METHODS

Efficacy analyses by sex were based on pooled data from two similar phase 3, randomized, double-blind, placebo-controlled, 3-month trials in elderly (≥65 years) and non-elderly (18-64 years) insomnia patients. Two age-adjusted (non-elderly/elderly) dose regimes of 40/30 and 20/15 mg were evaluated, with fewer patients assigned to 20/15 mg. Efficacy was assessed by patient-reported outcomes (N = 1264 women, 707 men) and by polysomnography endpoints in ~75% of patients. Safety analyses by sex (N = 1744 women, 1065 men) included pooled data from the two 3-month trials plus 3-month data from a safety trial of 40/30 mg.

RESULTS

The sex subgroup efficacy analyses mirrored the improvements seen for suvorexant 40/30 and 20/15 mg over placebo on patient-reported outcomes and polysomnography sleep maintenance and onset endpoints in the primary analyses; 95% CIs excluded zero in favor of suvorexant for most endpoints in both sexes, and similar efficacy was observed between sexes (95% CIs overlapped). Suvorexant was well-tolerated in women and men, although women in all treatment groups (including placebo) reported more adverse events than men. The most frequent adverse event was somnolence (women: 11.1% for 40/30 mg, 8.5% for 20/15 mg, 2.3% for placebo; men: 10.1% for 40/30 mg, 3.4% for 20/15 mg, 4.2% for placebo).

CONCLUSION

Suvorexant was generally effective and well-tolerated in both women and men with insomnia. ClinicalTrials.gov trial registration numbers: NCT01097616, NCT01097629, NCT01021813.

The dual orexin receptor antagonist, DORA-22, lowers histamine levels in the lateral hypothalamus and prefrontal cortex without lowering hippocampal acetylcholine

Chronic insomnia is defined as a persistent difficulty with sleep initiation maintenance or non-restorative sleep. The therapeutic standard of care for this condition is treatment with gamma-aminobutyric acid (GABA)_A receptor modulators, which promote sleep but are associated with a panoply of side effects, including cognitive and memory impairment. Dual orexin receptor antagonists (DORAs) have recently emerged as an alternative therapeutic approach that acts via a distinct and more selective wake-attenuating mechanism with the potential to be associated with milder side effects. Given their distinct mechanism of action, the current work tested the hypothesis that DORAs and GABA_A receptor modulators differentially regulate neurochemical pathways associated with differences in sleep architecture and cognitive performance induced by these pharmacological mechanisms. Our findings showed that DORA-22 suppresses the release of the wake neurotransmitter histamine in the lateral hypothalamus, prefrontal cortex, and hippocampus with no significant alterations in acetylcholine levels. In contrast, eszopiclone, commonly used as a GABA_A modulator, inhibited acetylcholine secretion across brain regions with variable effects on histamine release depending on the extent of wakefulness induction. In normal waking rats, eszopiclone only transiently suppressed histamine secretion, whereas this suppression was more obvious under caffeine-induced wakefulness. Compared with the GABA_A modulator eszopiclone, DORA-22 elicits a neurotransmitter profile consistent with wake reduction that does not impinge on neurotransmitter levels associated with cognition and rapid eye movement sleep.

Identification of Suvorexant in Urine Using Liquid Chromatography-Quadrupole/Time-of-Flight Mass Spectrometry (LC-Q/TOF-MS)

Suvorexant (Belsomra®) is a new hypnotic drug with a novel mechanism of action. In prescribed doses of 10 mg before bedtime, the drug produces rapid onset of sleep by inhibiting the orexin neurons of the arousal system, promoting decreased wakefulness. Suvorexant is a potent and highly selective dual orexin receptor antagonist. Sedative hypnotics are of forensic importance due to their widespread use, potential for additive effects with other central nervous system depressants, impairing effects and potential for misuse. In this report we describe a highly sensitive assay for the identification and quantification of suvorexant in urine. Suvorexant was isolated using liquid/liquid extraction (LLE) and identified using liquid chromatography-quadrupole/time-of-flight mass spectrometry. Suvorexant was quantified using a quadratic calibration model between 5 and 250 ng/mL (R2 = 1.000, n = 6). Processed sample stability was demonstrated for up to 24 h. The limit of detection was 0.5 ng/mL and the limit of quantification (LOQ) was 5 ng/mL. The accuracy, bias and precision of the assay at the LOQ were 99% (81-117%), -1% and 12% (n = 18). Intraassay (n = 5) and interassay (n = 15) precision (% CV) at 10, 50 and 200 ng/mL were ≤8%, and bias ranged from -2% to 4% (98-104% accuracy). No qualitative interferences were detected from matrix, internal standard or 50 common drugs. Matrix effects evaluated at low and high concentrations were -16% and -9%, respectively, and produced CVs of 11% and 5% (n = 20). Suvorexant is a new drug of forensic importance. In this report we describe how a simple acidic/neutral LLE can be used to isolate this lipophilic drug with high recoveries and sound analytical performance.

Clinical Practice Guideline for the Pharmacologic Treatment of Chronic Insomnia in Adults: An American Academy of Sleep Medicine Clinical Practice Guideline

INTRODUCTION

The purpose of this guideline is to establish clinical practice recommendations for the pharmacologic treatment of chronic insomnia in adults, when such treatment is clinically indicated. Unlike previous meta-analyses, which focused on broad classes of drugs, this guideline focuses on individual drugs commonly used to treat insomnia. It includes drugs that are FDA-approved for the treatment of insomnia, as well as several drugs commonly used to treat insomnia without an FDA indication for this condition. This guideline should be used in conjunction with other AASM guidelines on the evaluation and treatment of chronic insomnia in adults.

METHODS

The American Academy of Sleep Medicine commissioned a task force of four experts in sleep medicine. A systematic review was conducted to identify randomized controlled trials, and the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) process was used to assess the evidence. The task force developed recommendations and assigned strengths based on the quality of evidence, the balance of benefits and harms, and patient values and preferences. Literature reviews are provided for those pharmacologic agents for which sufficient evidence was available to establish recommendations. The AASM Board of Directors approved the final recommendations.

RECOMMENDATIONS

The following recommendations are intended as a guideline for clinicians in choosing a specific pharmacological agent for treatment of chronic insomnia in adults, when such treatment is indicated. Under GRADE, a STRONG recommendation is one that clinicians should, under most circumstances, follow. A WEAK recommendation reflects a lower degree of certainty in the outcome and appropriateness of the patient-care strategy for all patients, but should not be construed as an indication of ineffectiveness. GRADE recommendation strengths do not refer to the magnitude of treatment effects in a particular patient, but rather, to the strength of evidence in published data. Downgrading the quality of evidence for these treatments is predictable in GRADE, due to the funding source for most pharmacological clinical trials and the attendant risk of publication bias; the relatively small number of eligible trials for each individual agent; and the observed heterogeneity in the data. The ultimate judgment regarding propriety of any specific care must be made by the clinician in light of the individual circumstances presented by the patient, available diagnostic tools, accessible treatment options, and resources. We suggest that clinicians use suvorexant as a treatment for sleep maintenance insomnia (versus no treatment) in adults. (WEAK). We suggest that clinicians use eszopiclone as a treatment for sleep onset and sleep maintenance insomnia (versus no treatment) in adults. (WEAK). We suggest that clinicians use zaleplon as a treatment for sleep onset insomnia (versus no treatment) in adults. (WEAK). We suggest that clinicians use zolpidem as a treatment for sleep onset and sleep maintenance insomnia (versus no treatment) in adults. (WEAK). We suggest that clinicians use triazolam as a treatment for sleep onset insomnia (versus no treatment) in adults. (WEAK). We suggest that clinicians use temazepam as a treatment for sleep onset and sleep maintenance insomnia (versus no treatment) in adults. (WEAK). We suggest that clinicians use ramelteon as a treatment for sleep onset insomnia (versus no treatment) in adults. (WEAK). We suggest that clinicians use doxepin as a treatment for sleep maintenance insomnia (versus no treatment) in adults. (WEAK). We suggest that clinicians not use trazodone as a treatment for sleep onset or sleep maintenance insomnia (versus no treatment) in adults. (WEAK). We suggest that clinicians not use tiagabine as a treatment for sleep onset or sleep maintenance insomnia (versus no treatment) in adults. (WEAK). We suggest that clinicians not use diphenhydramine as a treatment for sleep onset and sleep maintenance insomnia (versus no treatment) in adults. (WEAK). We suggest that clinicians not use melatonin as a treatment for sleep onset or sleep maintenance insomnia (versus no treatment) in adults. (WEAK). We suggest that clinicians not use tryptophan as a treatment for sleep onset or sleep maintenance insomnia (versus no treatment) in adults. (WEAK). We suggest that clinicians not use valerian as a treatment for sleep onset or sleep maintenance insomnia (versus no treatment) in adults. (WEAK).