The dual orexin receptor antagonist suvorexant in alcohol use disorder and comorbid insomnia: A case report

Key Clinical Message

This case suggests using dual orexin receptor antagonists to treat alcohol use disorder and comorbid sleep disorders may be effective, commencing treatment in withdrawal and continuing it to prevent relapse.

Abstract

Effective medications for the treatment of alcohol use disorder are limited. This is partially due to the heterogenous nature of the symptomatology associated with alcohol use disorder and the abundance of presenting comorbidities. One common, and often overlooked, symptom that occurs during withdrawal of alcohol use is sleep disruption. Here, we report a case study of a participant with comorbid alcohol use disorder and insomnia. This participant was treated with a dual orexin receptor antagonist, suvorexant (Belsomra®), currently approved to treat insomnia. We demonstrate improvements in alcohol cravings, physical and psychological health, and sleep outcomes with treatment. These data support abundant preclinical and emerging clinical data in this space. The findings from this case report highlight the potential for suvorexant to treat comorbid alcohol use disorder and insomnia with fully powered, randomized controlled trials moving forward.

Suvorexant alters dynamics of the sleep-electroencephalography-power spectrum and depressive-symptom trajectories during inpatient opioid withdrawal

STUDY OBJECTIVES

Opioid withdrawal is an aversive experience that often exacerbates depressive symptoms and poor sleep. The aims of the present study were to examine the effects of suvorexant on oscillatory sleep-electroencephalography (EEG) band power during medically managed opioid withdrawal, and to examine their association with withdrawal severity and depressive symptoms.

METHODS

Participants with opioid use disorder (N = 38: age-range:21-63, 87% male, 45% white) underwent an 11-day buprenorphine taper, in which they were randomly assigned to suvorexant (20 mg [n = 14] or 40 mg [n = 12]), or placebo [n = 12], while ambulatory sleep-EEG data was collected. Linear mixed-effect models were used to explore: (1) main and interactive effects of drug group, and time on sleep-EEG band power, and (2) associations between sleep-EEG band power change, depressive symptoms, and withdrawal severity.

RESULTS

Oscillatory spectral power tended to be greater in the suvorexant groups. Over the course of the study, decreases in delta power were observed in all study groups (β = -189.082, d = -0.522, p = <0.005), increases in beta power (20 mg: β = 2.579, d = 0.413, p = 0.009 | 40 mg β = 5.265, d = 0.847, p < 0.001) alpha power (20 mg: β = 158.304, d = 0.397, p = 0.009 | 40 mg: β = 250.212, d = 0.601, p = 0.001) and sigma power (20 mg: β = 48.97, d = 0.410, p < 0.001 | 40 mg: β = 71.54, d = 0.568, p < 0.001) were observed in the two suvorexant groups. During the four-night taper, decreases in delta power were associated with decreases in depressive symptoms (20 mg: β = 190.90, d = 0.308, p = 0.99 | 40 mg: β = 433.33, d = 0.889 p = <0.001), and withdrawal severity (20 mg: β = 215.55, d = 0.034, p = 0.006 | 40 mg: β = 192.64, d = -0.854, p = <0.001), in both suvorexant groups and increases in sigma power were associated with decreases in withdrawal severity (20 mg: β = -357.84, d = -0.659, p = 0.004 | 40 mg: β = -906.35, d = -1.053, p = <0.001). Post-taper decreases in delta (20 mg: β = 740.58, d = 0.964 p = <0.001 | 40 mg: β = 662.23, d = 0.882, p = <0.001) and sigma power (20 mg only: β = 335.54, d = 0.560, p = 0.023) were associated with reduced depressive symptoms in the placebo group.

CONCLUSIONS

Results highlight a complex and nuanced relationship between sleep-EEG power and symptoms of depression and withdrawal. Changes in delta power may represent a mechanism influencing depressive symptoms and withdrawal.

Interaction modes of human orexin 2 receptor with selective and nonselective antagonists studied by NMR spectroscopy

Orexin neuropeptides have many physiological roles in the sleep-wake cycle, feeding behavior, reward demands, and stress responses by activating cognitive receptors, the orexin receptors (OX1R and OX2R), distributed in the brain. There are only subtle differences between OX1R and OX2R in the orthosteric site, which has hindered the rational development of subtype-selective antagonists. In this study, we utilized solution-state NMR to capture the structural plasticity of OX2R labeled with 13CH3-ε-methionine in complex with antagonists. Mutations in the orthosteric site allosterically affected the intracellular tip of TM6. Ligand exchange experiments with the subtype-selective EMPA and the nonselective suvorexant identified three methionine residues that were substantially perturbed. The NMR spectra suggested that the suvorexant-bound state exhibited more structural plasticity than the EMPA-bound state, which has not been foreseen from the close similarity of their crystal structures, providing insights into dynamic features to be considered in understanding the ligand recognition mode.

Clinical safety and narcolepsy-like symptoms of dual orexin receptor antagonists in patients with insomnia: a systematic review and meta-analysis

STUDY OBJECTIVES

Dual orexin receptor antagonists (DORAs) are emerging treatments for insomnia. This meta-analysis study aimed to assess the safety of FDA-approved DORAs (suvorexant, lemborexant, and daridorexant), focusing on narcolepsy-like symptoms associated with these drugs.

METHODS

Five prominent databases were searched to identify randomized controlled trials (RCTs) on this topic. Primary safety outcomes included treatment-emergent adverse events (TEAEs), treatment-related TEAEs, TEAEs leading to discontinuation, and serious TEAEs. Excessive daytime sleepiness (EDS), sleep paralysis, and hallucinations were categorized as adverse events (AEs)-related narcolepsy-like symptoms.

RESULTS

Eleven RCTs with 7703 patients were included. DORAs were associated with a higher risk of TEAEs (risk ratio [RR], 1.09; 95% confidence interval [CI], 1.03 to 1.15) and treatment-related TEAEs (RR, 1.69; 95% CI: 1.49 to 1.92) when compared to placebo. The DORA group exhibited a significantly higher risk of EDS (RR, 2.15; 95% CI: 1.02 to 4.52) and sleep paralysis (RR, 3.40; 95% CI: 1.18 to 9.80) compared to the placebo group.

CONCLUSION

This meta-analysis achieved a comparative evaluation of the clinical safety and tolerability of FDA-approved DORAs for primary insomnia, specifically focusing on AEs-related narcolepsy-like symptoms. This study contributes to understanding the safety profile of FDA-approved DORAs for treating insomnia.

Orexin Receptor Antagonism: Normalizing Sleep Architecture in Old Age and Disease

Sleep is essential for human well-being, yet the quality and quantity of sleep reduce as age advances. Older persons (>65 years old) are more at risk of disorders accompanied and/or exacerbated by poor sleep. Furthermore, evidence supports a bidirectional relationship between disrupted sleep and Alzheimer's disease (AD) or related dementias. Orexin/hypocretin neuropeptides stabilize wakefulness, and several orexin receptor antagonists (ORAs) are approved for the treatment of insomnia in adults. Dysregulation of the orexin system occurs in aging and AD, positioning ORAs as advantageous for these populations. Indeed, several clinical studies indicate that ORAs are efficacious hypnotics in older persons and dementia patients and, as in adults, are generally well tolerated. ORAs are likely to be more effective when administered early in sleep/wake dysregulation to reestablish good sleep/wake-related behaviors and reduce the accumulation of dementia-associated proteinopathic substrates. Improving sleep in aging and dementia represents a tremendous opportunity to benefit patients, caregivers, and health systems.

Effect of lemborexant on pharmacokinetics of clozapine: A potential drug-drug interaction mediated by time-dependent inhibition of CYP3A4

Clozapine (CLZ) is extensively used for treatment-resistant schizophrenia (TRS) with caution to avoid serious adverse events such as agranulocytosis and drug-drug interactions (DDIs). In the current report, we present a case of a 35-year-old male non-smoking TRS patient whose steady-state plasma trough concentrations (Ctrough ) of CLZ and its active metabolite, N-desmethylclozapine (NDMC), were significantly increased after initiating oral administration of lemborexant (LEM), a dual orexin receptor antagonist, for the treatment of insomnia. The patient experienced oversedation with sleepiness and fatigue while maintaining high levels of Ctrough of CLZ. The increased concentrations of CLZ returned to normal ranges after the discontinuation of LEM dosing, implying a pharmacokinetic DDI between CLZ and LEM. To gain insight into possible mechanisms, we performed in vitro assays of CYP1A2- and CYP3A4-mediated CLZ metabolism by measuring the formations of NDMC and clozapine N-oxide (CNO). In accordance with previous studies, the incubation of CLZ with each enzyme resulted in the production of both metabolites. LEM had only a weak inhibitory effect on CYP1A2- and CYP3A4-mediated CLZ metabolism. However, the preincubation of LEM with CYP3A4 in the presence of NADPH showed a significant enhancement of inhibitory effects on CLZ metabolism with IC50 values for the formations of CNO and NDMC of 2.8 μM and 4.1 μM, respectively, suggesting that LEM exerts as a potent time-dependent inhibitor for CYP3A4. Taken together, the results of the current study indicate that co-medication of CLZ with LEM may lead to increase in exposure to CLZ and risks of CLZ-related adverse events.

Orexin 2 receptor antagonism sex-dependently improves sleep/wakefulness and cognitive performance in tau transgenic mice

BACKGROUND AND PURPOSE

Tau pathology contributes to a bidirectional relationship between sleep disruption and neurodegenerative disease. Tau transgenic rTg4510 mice model tauopathy symptoms, including sleep/wake disturbances, which manifest as marked hyperarousal. This phenotype can be prevented by early transgene suppression; however, whether hyperarousal can be rescued after onset is unknown.

EXPERIMENTAL APPROACH

Three 8-week experiments were conducted with wild-type and rTg4510 mice after age of onset of hyperarousal (4.5 months): (1) Tau transgene suppression with doxycycline (200 ppm); (2) inactive phase rapid eye movement (REM) sleep enhancement with the dual orexin receptor antagonist suvorexant (50 mg·kg-1 ·day-1 ); or (3) Active phase non-NREM (NREM) and REM sleep enhancement using the selective orexin 2 (OX2 ) receptor antagonist MK-1064 (40 mg·kg-1 ·day-1 ). Sleep was assessed using polysomnography, cognition using the Barnes maze, and tau pathology using immunoblotting and/or immunohistochemistry.

KEY RESULTS

Tau transgene suppression improved tauopathy and hippocampal-dependent spatial memory, but did not modify hyperarousal. Pharmacological rescue of REM sleep deficits did not improve spatial memory or tau pathology. In contrast, normalising hyperarousal by increasing both NREM and REM sleep via OX2 receptor antagonism restored spatial memory, independently of tauopathy, but only in male rTg4510 mice. OX2 receptor antagonism induced only short-lived hypnotic responses in female rTg4510 mice and did not improve spatial memory, indicating a tau- and sex-dependent disruption of OX2 receptor signalling.

CONCLUSIONS AND IMPLICATIONS

Pharmacologically reducing hyperarousal corrects tau-induced sleep/wake and cognitive deficits. Tauopathy causes sex-dependent disruptions of OX2 receptor signalling/function, which may have implications for choice of hypnotic therapeutics in tauopathies.

Lack of Efficacy of Suvorexant in People with Insomnia and Poorly Controlled Type 2 Diabetes

Objective/Background

Sleep disturbance is a common and underappreciated feature of diabetes and sleep may contribute to glycemic control in people with type 2 diabetes (T2D). We conducted a 3-month trial to examine the efficacy of suvorexant in improving sleep and health outcomes in people with suboptimally controlled T2D and insomnia.

Participants/Methods

This parallel, double-blind, randomized placebo-controlled trial was conducted using the sequential parallel comparison design (SPCD). Sixty-nine people with poorly controlled T2D (HbA1c ≥ 6.5) were randomized to placebo and/or suvorexant (10-20 mg). The primary outcome was subjective total sleep time (sTST), and secondary outcomes were Insomnia Severity Index (ISI) score and wake time after sleep onset (WASO). Exploratory outcomes included sleep efficiency, hemoglobin A1c (HbA1c), and C-reactive protein (CRP). Exploratory analyses were conducted on relationships between sleep and diabetes outcomes.

Results

There were no significant improvements in sTST (p = 0.27), ISI (p = 0.86), or WASO (p = 0.94) among participants taking suvorexant compared to placebo. There were also no significant changes in any of the exploratory endpoints. Improvements in sleep were associated with improvements in both objective (ie, HbA1c) and subjective (ie, Diabetes Distress Scale) measures of diabetes, as well as reductions in depressive symptoms, independent of treatment assignment.

Conclusion

The study did not find evidence that suvorexant is efficacious for insomnia in people with poorly controlled T2D. The associations of improved sleep with improvements in both diabetes-related metrics and depressive symptoms across groups highlight the importance of identifying and treating sleeping difficulties in this population.

CT Registration #

Nct03818581.

The orexin story and orexin receptor antagonists for the treatment of insomnia

Insomnia is present in up to one third of the adult population worldwide, and it can present independently or with other medical conditions such as mental, metabolic, or cardiovascular diseases, which highlights the importance of treating this multifaceted disorder. Insomnia is associated with an abnormal state of hyperarousal (increased somatic, cognitive, and cortical activation) and orexin has been identified as a key promotor of arousal and vigilance. The current standards of care for the treatment of insomnia recommend non-pharmacological interventions (cognitive behavioural therapy) as first-line treatment and, if behavioural interventions are not effective or available, pharmacotherapy. In contrast to most sleep medications used for decades (benzodiazepines and 'Z-drugs'), the new orexin receptor antagonists do not modulate the activity of γ-aminobutyric acid receptors, the main inhibitory mechanism of the central nervous system. Instead, they temporarily block the orexin pathway, causing a different pattern of effects, e.g., less morning or next-day effects, motor dyscoordination, and cognitive impairment. The pharmacokinetic/pharmacodynamic properties of these drugs are the basis of the different characteristics explained in the package inserts, including the recommended starting dose. Orexin receptor antagonists seem to be devoid of any dependence and tolerance-inducing effects, rendering them a viable option for longer-term treatment. Safety studies did not show exacerbation of existing respiratory problems, but more real-world safety and pharmacovigilance experience is needed. This review provides an overview of the orexin history, the mechanism of action, the relation to insomnia, and key features of available drugs mediating orexin signalling.

Failure of the dual orexin receptor antagonist suvorexant to engender drug discrimination in rats

For abuse potential assessment, U.S. Food and Drug Administration (FDA) requests that new, brain-penetrating drugs are ideally compared with approved drugs that share the mechanism of action and are judged to have abuse liability by the Drug Enforcement Agency. For development of the dual orexin receptor antagonist (DORA) daridorexant, the FDA recommended conducting a rat drug discrimination paradigm against the approved, schedule IV, DORA suvorexant. Surprisingly, at suvorexant plasma levels up to three-fold the maximum concentration at the highest approved human dose, rats did not learn to discriminate the suvorexant stimulus from vehicle.

Efficacy and safety of pharmacotherapy in chronic insomnia: A review of clinical guidelines and case reports

Introduction

Chronic insomnia affects 5% to 10% of the US population, increasing the demand for treatment options and the corresponding research to prove their validity.1 This review compares recommendations from 3 clinical guidelines and summarizes hypnotic medications, including their newly reported side effects not mentioned in the guidelines. In addition, we aim to provide an overview of what pharmacotherapies are available for prescribers and patients.

Methods

A literature search was conducted for articles published prior to January 10, 2022, and case reports and clinical studies were retrieved from PubMed and Google Scholar.

Results

Definitive conclusions cannot be drawn regarding the safety and efficacy of medications reviewed; however, trends are apparent. All 3 guidelines included in this review remarked most treatment recommendations as weak except for cognitive behavioral therapy for insomnia, which is effective but not readily available. Furthermore, based on the 15 case reports and 13 clinical studies presented in this review, many of the medications used for treatment of insomnia present safety concerns.

Discussion

Benzodiazepines and benzodiazepine receptor agonists are commonly used hypnotic agents with the "Z-drugs" having robust data establishing their efficacy for the short-term treatment of chronic insomnia. However, significant adverse effects related to the central nervous system (CNS), including developing tolerance, addiction, CNS depression, and amnesia, remain barriers to their long-term use. In comparison, newer agents present more favorable side-effect profiles although with less established efficacy. Additionally, off-label agents, including antidepressants, antihistamines, and natural supplements, are discussed due to their prominent use.

Orexin Receptor Antagonists as Adjunct Drugs for the Treatment of Depression: A Mini Meta-Analysis

Introduction

There is growing interest in the efficacy of orexin receptor antagonists (ORA), one of the new psychopharmacological agents used in the treatment of insomnia, in other psychiatric disorders such as depression.

Methods

This meta-analysis was conducted in accordance with PRISMA requirements. Literature searches were conducted using PubMed, Scopus and EBSCO (Medline) databases. Search words were (depression OR mood disorder OR affective disorder) AND (orexin OR orx OR hypocretin OR orx1 OR orx2 OR orexin receptor antagonist OR almorexant OR suvorexant OR lemborexant OR daridorexant OR seltorexant OR vornorexant OR filorexant). No date restrictions were used. The random effects model was used for analyses with I2 values above 50% and fixed effects model was used for analyses with I2 values below 50%.

Results

In the acute phase, ORAs had no significant effect on core, sleep-adjusted and total symptoms of depression respectively; Standardized Mean Difference (SMD) for random effect -0.422, 95% CI [-0.90; 0.06], p=0.089, I2=62.4%; SMD for random effect -0.375, 95% CI [-1.24; 0.49], p=0.400; I2=66.6% and SMD for random effect -0.477, 95% CI [-0.97; 0.01], p=0.059; I2=83.1%). However, they had a significant effect on core and total symptoms of depression in the early period respectively; SMD for fixed effect=-0.228, 95% CI [-0.44; -0.01], p=0.036, I2=9.1%; and SMD for fixed effect=-0.186, 95% CI [-0.37; -0.001], p=0.048, I2=0.0%, respectively).

Conclusion

The results of this meta-analysis suggest that ORAs may provide direct antidepressant efficacy when added to existing antidepressant treatment and may also have indirect antidepressant effects through improvement in sleep symptoms. Considering the physiological effects of orexin on behaviors, ORAs may be promising new treatment modalities in the treatment of many psychiatric disorders other than insomnia. However, these results are preliminary and further studies with different ORAs at different doses and with different samples are needed.

Different doses of dual orexin receptor antagonists in primary insomnia: a Bayesian network analysis

Background: Systematic comparisons of the doses of the Food and Drug Administration (FDA)-approved dual orexin receptor antagonists (DORAs) for people with insomnia are limited. Methods: PubMed, Embase, Cochrane Library, and Clinicaltrials. gov were systematically searched to identify relevant studies published before 31 October 2022. We assessed the certainty of evidence using the confidence in network meta-analysis (CINeMA) framework. Results: We pooled 7257 participants from 9 randomized controlled trials (RCTs). Moderate to high certainty evidence demonstrated suvorexant (20 and 40 mg) and daridorexant (10 and 50 mg) as the most effective in latency to persistent sleep (LPS) reduction. Lemborexant at 5 and 10 mg was the most effective in subjective sleep onset time (sTSO) reduction. For wake time after sleep onset (WASO), all drugs except daridorexant 5 mg were more effective than placebo. Lemborexant 5 mg was among the best in subjective WASO (sWASO) (moderate to high certainty) and had the highest surface under the curve ranking area (SUCRA) values for sWASO (100%). For total sleep time (TST), suvorexant and daridorexant, except the respective minimum doses, were more effective than placebo, while suvorexant 40 mg and lemborexant 10 mg may have been the most effective for subjective TST (sTST) (low to very low certainty). Suvorexant 40 mg (RR 1.09), suvorexant 80 mg (RR 1.65), and daridorexant 25 mg (RR 1.16) showed a higher safety risk than placebo. Conclusion: Suvorexant 20 mg, lemborexant 5 mg, lemborexant 10 mg, and daridorexant 50 mg represent suitable approaches for insomnia. Clinical Trial Registration: clinicaltrials.gov, PROSPERO (CRD42022362655).

Efficacy and safety of lemborexant as an alternative drug for patients with insomnia taking GABA-BZ receptor agonists or suvorexant

BACKGROUND

Although gamma-aminobutyric acid-benzodiazepine (GABA-BZ) receptor agonists are used to treat insomnia, their long-term or high-dosage use causes adverse events. Nevertheless, evidence regarding the discontinuation and replacement of GABA-BZ receptor agonists with alternative agents is lacking. Suvorexant (SUX), an existing orexin receptor antagonist, is effective in preventing nocturnal awakening in 70-75% of patients with insomnia.

METHODS

The novel dual orexin receptor antagonist lemborexant (LEM) has fewer adverse effects than GABA-BZ receptor agonists. Therefore, in this retrospective study, we categorised patients taking GABA-BZ receptor agonists and SUX into LEM-treated (switched) and non-treated (non-switched) groups and compared their outcomes over a 12-week period.

RESULTS

The GABA-BZ group (N=59) comprised 34 'switched' and 25 'non-switched' and the SUX group (N=14) comprised 6 'switched' and 8 'non-switched' patients. A mixed model showed a significant diazepam equivalence reduction in patients taking GABA-BZ receptor agonists and improved Athens Insomnia Scale score in those taking SUX. The safety and tolerability of GABA-BZ receptor agonists and SUX were high, and no serious adverse effects were observed after switching to LEM.

CONCLUSIONS

LEM may be a useful alternative for long-term GABA-BZ receptor agonist users. For SUX, the number of cases (N=6) was insufficient to draw definite conclusions. This article is protected by copyright. All rights reserved.

Suvorexant, an FDA-approved dual orexin receptor antagonist, reduces oxycodone self-administration and conditioned reinstatement in male and female rats

Background: The Department of Health and Human Services reports that prescription pain reliever (e.g., oxycodone) misuse was initiated by 4,400 Americans each day in 2019. Amid the opioid crisis, effective strategies to prevent and treat prescription opioid use disorder (OUD) are pressing. In preclinical models, the orexin system is recruited by drugs of abuse, and blockade of orexin receptors (OX receptors) prevents drug-seeking behavior. The present study sought to determine whether repurposing suvorexant (SUV), a dual OX receptor antagonist marketed for the treatment of insomnia, can treat two features of prescription OUD: exaggerated consumption and relapse. Methods: Male and female Wistar rats were trained to self-administer oxycodone (0.15 mg/kg, i. v., 8 h/day) in the presence of a contextual/discriminative stimulus (S^D) and the ability of SUV (0-20 mg/kg, p. o.) to decrease oxycodone self-administration was tested. After self-administration testing, the rats underwent extinction training, after which we tested the ability of SUV (0 and 20 mg/kg, p. o.) to prevent reinstatement of oxycodone seeking elicited by the S^D. Results: The rats acquired oxycodone self-administration and intake was correlated with the signs of physical opioid withdrawal. Additionally, females self-administered approximately twice as much oxycodone as males. Although SUV had no overall effect on oxycodone self-administration, scrutiny of the 8-h time-course revealed that 20 mg/kg SUV decreased oxycodone self-administration during the first hour in males and females. The oxycodone S^D elicited strong reinstatement of oxycodone-seeking behavior that was significantly more robust in females. Suvorexant blocked oxycodone seeking in males and reduced it in females. Conclusions: These results support the targeting of OX receptors for the treatment for prescription OUD and repurposing SUV as pharmacotherapy for OUD.

Alternative use of suvorexant (Belsomra®) for the prevention of alcohol drinking and seeking in rats with a history of alcohol dependence

Alcohol use disorder (AUD) is one of the most treatment-resistant medical conditions globally. The orexin (Orx) system regulates diverse physiological processes, including stress, and is a system of interest for the development of pharmaceuticals to treat substance use disorders, particularly AUD. The present study tested the ability of the dual orexin receptor antagonist suvorexant (SUV), marketed by Merck as Belsomra^®, for the treatment of insomnia, to decrease alcohol self-administration and the stress-induced reinstatement of alcohol-seeking behavior in male Wistar rats with a history of alcohol dependence. Rats were trained to orally self-administer 10% alcohol (30 min/day for 3 weeks) and were either made dependent via chronic intermittent alcohol vapor exposure (14 h ON, 10 h OFF) for 6 weeks or exposed to air (non-dependent). Starting on week 7, the effect of SUV (0-20 mg/kg, p.o.) was tested on alcohol self-administration at acute abstinence (8 h after vapor was turned OFF) twice weekly. A separate cohort of rats that were prepared in parallel was removed from alcohol vapor exposure and then subjected to extinction training for 14 sessions. Once extinction was achieved, the rats received SUV (0 and 5 mg/kg, p.o.) and were tested for the footshock stress-induced reinstatement of alcohol-seeking behavior. Suvorexant at 5, 10, and 20 mg/kg selectively decreased alcohol intake in dependent rats. Furthermore, 5 mg/kg SUV prevented the stress-induced reinstatement of alcohol-seeking behavior in dependent rats only. These results underscore the significance of targeting the Orx system for the treatment of substance use disorders generally and suggest that repurposing SUV could be an alternative approach for the treatment of AUD.

Cost-effectiveness analysis of lemborexant for treating insomnia in Japan: a model-based projection, incorporating the risk of falls, motor vehicle collisions, and workplace accidents

BACKGROUND

Lemborexant has demonstrated statistically significant improvements in sleep onset and sleep maintenance compared with placebo and zolpidem tartrate extended release, measured both objectively using polysomnography and subjectively using sleep diaries, in the phase 3 clinical trial SUNRISE 1. This study evaluated the cost-effectiveness of lemborexant compared with suvorexant, zolpidem immediate release (IR), and untreated insomnia.

METHODS

A decision-tree model was developed for falls, motor vehicle collisions, and workplace accidents associated with insomnia and insomnia treatments from a Japanese healthcare perspective and with a 6-month time horizon. The model extracted subjective sleep onset latency treatment responses and disutility values for non-responders from SUNRISE 1. Cost-effectiveness was assessed using incremental cost per quality-adjusted life year (QALY) gained. One-way and probabilistic sensitivity analyses were conducted to evaluate the impact of parameter uncertainty on the results.

RESULTS

In the base-case analysis, the mean estimated QALYs for lemborexant, suvorexant, zolpidem-IR, and untreated insomnia were 0.4220, 0.4204, 0.4113, and 0.4163, and expected medical costs were JPY 34 034, JPY 38 371, JPY 38 139, and JPY 15 383, respectively. Lemborexant saved JPY 4337 and JPY 4105 compared with suvorexant or zolpidem-IR, respectively, while conferring QALY benefits. The incremental cost-effectiveness ratio (ICER) of lemborexant compared with that of untreated insomnia was JPY 3 220 975 /QALY. Lemborexant was dominant over suvorexant and zolpidem-IR and was cost-effective when compared with untreated insomnia. Sensitivity analyses supported the results' robustness.

CONCLUSIONS

In a Japanese clinical practice setting, lemborexant may represent a better investment for treating insomnia in the healthcare system in Japan.

Effectiveness of change from suvorexant to lemborexant drug in the treatment of sleep disorders

BACKGROUND

This study aimed to examine the effects of a change in medication from suvorexant to lemborexant among patients with insomnia.

METHODS

Patients with chronic insomnia who had persistent insomnia for 3 months or longer and who had been taking suvorexant for 3 months or longer were selected. The participants were divided into two groups: the 'modified' group and the 'non-modified' group. Four sub-types of insomnia (i.e., difficulty initiating sleep, difficulty maintaining sleep, early-morning awakening, and non-restorative sleep) were investigated. Logistic regression was used to investigate improvements in both the groups after 12 weeks.

RESULTS

Among the 77 participants, 43 and 34 patients were in the modified drug group and the non-modified drug group, respectively. Comparing sleep disorders between the two groups, we found significant improvement after 12 weeks in the modified drug group in terms of difficulty initiating sleep, compared with the non-modified drug group (odds ratio = 0.036, P = 0.008, 95% CI = 0.003-0.415). However, no significant differences were found between the two groups in terms of difficulty maintaining sleep, early-morning awakening, and non-restorative sleep.

CONCLUSIONS

Sleep disorders can be treated by alleviating difficulties in initiating sleep by changing from suvorexant to lemborexant. In addition, it was confirmed that the drug change caused no serious side effects and that it was highly safe and tolerated.

Evaluation of suvorexant for trauma-related insomnia

STUDY OBJECTIVES

Effective pharmacological treatments for sleep disturbance related to trauma with and without co-occurring posttraumatic stress disorder (PTSD) are needed. There is debate regarding what effects on rapid eye movement sleep (REMS) would be beneficial. Suvorexant is the first dual orexin receptor antagonist (DORA) approved for the treatment of insomnia. In contrast to most psychotropic agents, DORAs can enhance REMS while reducing arousal. We evaluated 6 weeks of suvorexant treatment for trauma-related insomnia in a double-blind, placebo-controlled clinical trial with clinical and polysomnographic evaluation.

METHODS

Participants with insomnia that followed a traumatic event were recruited from the community. Representation of current, past-only, and never having met criteria for PTSD was similar and most participants had experienced trauma-related nightmares. Participants were randomly assigned to receive suvorexant or placebo, initially at 10 mg and increased to 20 mg after 1 week, if tolerated. Polysomnography was obtained for screening, at baseline, and at 2 weeks of treatment.

RESULTS

The thirty-seven evaluable participants had significant improvement of PTSD and insomnia symptoms, however, there were no significant interactions with treatment condition. Medication was well tolerated with only one dropout being related to side effects. Within the suvorexant group increased REM segment duration correlated with concurrent PTSD symptom reduction. Nightmares remitted in all of the participants who received suvorexant and all but one of those receiving placebo.

CONCLUSIONS

A robust placebo response undermined detecting a medication effect. Further evaluation of DORAs for trauma-related insomnia, as well as factors contributing to placebo-response, are warranted.

Hypocretins (orexins): The ultimate translational neuropeptides

The hypocretins (Hcrts), also known as orexins, are two neuropeptides produced exclusively in the lateral hypothalamus. They act on two specific receptors that are widely distributed across the brain and involved in a myriad of neurophysiological functions that include sleep, arousal, feeding, reward, fear, anxiety and cognition. Hcrt cell loss in humans leads to narcolepsy with cataplexy (narcolepsy type 1), a disorder characterized by intrusions of sleep into wakefulness, demonstrating that the Hcrt system is nonredundant and essential for sleep/wake stability. The causal link between Hcrts and arousal/wakefulness stabilisation has led to the development of a new class of drugs, Hcrt receptor antagonists to treat insomnia, based on the assumption that blocking orexin-induced arousal will facilitate sleep. This has been clinically validated: currently, two Hcrt receptor antagonists are approved to treat insomnia (suvorexant and lemborexant), with a New Drug Application recently submitted to the US Food and Drug Administration for a third drug (daridorexant). Other therapeutic applications under investigation include reduction of cravings in substance-use disorders and prevention of neurodegenerative disorders such as Alzheimer's disease, given the apparent bidirectional relationship between poor sleep and worsening of the disease. Circuit neuroscience findings suggest that the Hcrt system is a hub that integrates diverse inputs modulating arousal (e.g., circadian rhythms, metabolic status, positive and negative emotions) and conveys this information to multiple output regions. This neuronal architecture explains the wealth of physiological functions associated with Hcrts and highlights the potential of the Hcrt system as a therapeutic target for a number of disorders. We discuss present and future possible applications of drugs targeting the Hcrt system for the treatment of circuit-related neuropsychiatric and neurodegenerative conditions.

Suvorexant with or without ramelteon to prevent delirium: a systematic review and meta-analysis

Delirium is a common and serious neurobehavioral syndrome, associated with prolonged hospital stays, and increased morbidity and mortality. As it remains unclear whether suvorexant with or without ramelteon prevents delirium in elderly hospitalized patients, we conducted a systematic review and meta-analysis to evaluate, searching the PubMed, Cochrane Library, Web of Science, EMBASE, and EBSCOhost databases for all randomized controlled trials (RCTs), case-control studies, and cohort studies that investigated the effects of suvorexant with or without ramelteon on delirium in adult hospitalized patients. The primary outcome was the incidence of delirium. Two randomized controlled trials, 7 cohort studies and 2 case-control studies involving 2594 patients were included in this meta-analysis. The results showed that both suvorexant alone (odds ratio (OR) = 0.30, 95% confidence interval (CI): 0.14-0.65, P = 0.002) and suvorexant with ramelteon (OR = 0.39, 95% CI 0.23-0.65, P = 0.0003) reduced the incidence of delirium in adult hospitalized patients. Six studies involved the use of benzodiazepines; subgroup analysis performed separately in the suvorexant alone and suvorexant with ramelteon groups indicated that when benzodiazepine was administered, suvorexant with ramelteon was effective at reducing the incidence of delirium (OR = 0.53, 95% CI 0.37-0.74, P = 0.0002), but no significant difference was observed for suvorexant alone (OR = 0.40, 95% CI 0.11-1.53, P = 0.18). The current literature thus supports the effectiveness of suvorexant with or without ramelteon for delirium prevention, although suvorexant alone failed to significantly reduce the incidence of delirium when benzodiazepine was administered. The present study was limited by the significant heterogeneity among the included studies, and caution should be exercised when interpreting the results. This study was registered in the PROSPERO database (CRD4202017964).

Differential sleep/wake response and sex effects following acute suvorexant, MK-1064 and zolpidem administration in the rTg4510 mouse model of tauopathy

Background and Purpose

Transgenic mouse models of tauopathy display prominent sleep/wake disturbances which manifest primarily as a hyperarousal phenotype during the active phase, suggesting that tau pathology contributes to sleep/wake changes. However, no study has yet investigated the effect of sleep‐promoting compounds in these models. Such information has implications for the use of hypnotics as potential therapeutic tools in tauopathy‐related disorders.

Experimental Approach

This study examined polysomnographic recordings in 6‐6.5‐month‐old male and female rTg4510 mice following acute administration of suvorexant (50 mg·kg⁻¹), MK‐1064 (30 mg·kg⁻¹) or zolpidem (10 mg·kg⁻¹), administered at the commencement of the active phase.

Key Results

Suvorexant, a dual OX receptor antagonist, promoted REM sleep in rTg4510 mice, without affecting wake or NREM sleep. MK‐1064, a selective OX₂ receptor antagonist, reduced wake and increased NREM and total sleep time. MK‐1064 normalised the hyperarousal phenotype of male rTg4510 mice, whereas female rTg4510 mice exhibited a more transient response. Zolpidem, a GABA_A receptor positive allosteric modulator, decreased wake and increased NREM sleep in both male and female rTg4510 mice. Of the three compounds, the OX₂ receptor antagonist MK‐1064 promoted and normalised physiologically normal sleep, especially in male rTg4510 mice.

Conclusions and Implications

Our findings indicate that hyperphosphorylated tau accumulation and associated hyperarousal does not significantly alter the responses of tauopathy mouse models to hypnotics. However, the sex differences observed in the sleep/wake response of rTg4510 mice to MK‐1064, but not suvorexant or zolpidem, raise questions about therapeutic implications for the use of OX₂ receptor antagonists in human neurodegenerative disorders.

Dual orexin receptor antagonists for treatment of insomnia: A systematic review and meta-analysis on randomized, double-blind, placebo-controlled trials of suvorexant and lemborexant

STUDY OBJECTIVES

Recent treatment guidelines for chronic insomnia recommend pharmacological and non-pharmacological therapies. One of the contemporary drug options for insomnia includes dual orexin receptor antagonist (DORA), such as suvorexant and lemborexant. We conducted a systematic review and meta-analysis for the treatment of insomnia with suvorexant and lemborexant based on randomized, double-blind, placebo-controlled Trials.

METHODS

We conducted a comprehensive search on three databases (PubMed/Medline, Web of Science, and Cochrane Library) till August 14, 2021, without any restrictions to retrieve the relevant articles. The effect sizes were computed presenting the pooled mean difference or risk ratio along with 95% confidence interval of each outcome.

RESULTS

Our search showed eight articles (five for suvorexant and three for lemborexant). Results of diary measures, rating scales, polysomnography results, treatment discontinuation, and adverse events were measured. All efficacy outcome measures favorably and significantly differed in the suvorexant compared to placebo. Safety profile did not differ significantly except for somnolence, excessive daytime sleepiness/sedation, fatigue, back pain, dry mouth, and abnormal dreams. Important adverse events including hallucinations, suicidal ideation/behavior and motor vehicle accidents did not differ between suvorexant and placebo. All the efficacy outcomes significantly differed between lemborexant 5 and lemborexant 10 compared to placebo. Somnolence rate for lemborexant 5 and lemborexant 10 and nightmare for lemborexant 10 were significantly higher than placebo.

CONCLUSION

The present meta-analysis reported that suvorexant and lemborexant are efficacious and safe agents for the patients with insomnia. Further data in patients with insomnia and various comorbid conditions are needed.

Effects of benzodiazepine and orexin receptor antagonist on cognitive function revealed by auditory event-related potentials

BACKGROUND

Cognitive decline after oral administration of sedatives, such as benzodiazepines, is a serious side effect. Suvorexant, an orexin receptor antagonist, has a favorable tolerability and a limited side-effect profile.

AIM

The purpose of this study was to estimate the cognitive decline 1 day after oral medication with lormetazepam, a benzodiazepine, and suvorexant by comparing mismatch negativity (MMN) and P300 reflecting auditory discrimination function.

METHODS

Sixty healthy subjects (42 males) were randomly assigned to three groups receiving suvorexant 20 mg, lormetazepam 2 mg, or placebo in this double-blind, randomized control study. Event-related potential recordings during an auditory oddball task and a digit symbol substitution test (DSST) were performed 1 day after oral administration.

RESULTS

MMN, on the day after oral administration, was significantly attenuated in the lormetazepam group compared with the other two groups, but there was no difference between the suvorexant and placebo groups. No significant difference was found in P300 amplitudes and DSST scores among the three groups.

CONCLUSION

These findings suggest that suvorexant, unlike benzodiazepine, is not associated with cognitive deficits, as revealed by MMN but not P300. This study shows a neurophysiological difference in the effects of suvorexant and benzodiazepine on cognitive function.

Abuse potential assessment of the new dual orexin receptor antagonist daridorexant in recreational sedative drug users as compared to suvorexant and zolpidem

STUDY OBJECTIVES

Abuse potential properties have been reported for the dual orexin receptor antagonists (DORAs) suvorexant and lemborexant. Daridorexant is a new DORA currently in late-stage clinical development. This randomized, double-blind, double-dummy, placebo- and active-controlled 6-period crossover study assessed its abuse potential in healthy recreational sedative drug users (n=63).

METHODS

In each study period, a single, oral, morning dose of either daridorexant (50, 100, 150 mg), placebo, or active control, i.e., suvorexant (150 mg) or zolpidem (30 mg), was administered. Primary pharmacodynamic endpoint was the Emax of the Drug-liking visual analog scale (VAS) assessed over 24 h. Several secondary subjective and objective pharmacodynamic endpoints were also assessed.

RESULTS

Study validity was confirmed based on drug-liking of suvorexant and zolpidem greater than placebo applying a pre-defined 15-point validity margin (p<0.0001). Drug-liking VAS Emax (mean; 95% CI) of daridorexant at 50 mg (73.2; 69.0-77.5) was significantly lower compared to suvorexant (80.7; 77.0-84.5) and zolpidem (79.9; 76.2-83.5) (p<0.001), but similar at 100 mg (79.1; 75.0-83.3) and 150 mg (81.3; 77.7, 84.8). Such dose-related patterns were also observed for most secondary endpoints. At each daridorexant dose, Drug-liking VAS scores were greater than placebo. Both control drugs and daridorexant were safe and the pharmacokinetics of daridorexant was consistent with earlier trials indicating quick absorption and elimination.

CONCLUSIONS

In this large, valid human abuse potential study, daridorexant showed dose-related drug-liking among recreational sedative drug users with lower effects at the highest phase-3 dose, and similar effects at higher doses compared to supratherapeutic doses of suvorexant and zolpidem.

Pilot evaluation of a consumer wearable device to assess sleep in a clinical polysomnography trial of suvorexant for treating insomnia in patients with Alzheimer's disease

The orexin receptor antagonist suvorexant was previously reported to significantly improve total sleep time (TST), by 28 min per night versus placebo after 4 weeks, in a sleep laboratory polysomnography (PSG) study of patients with Alzheimer's disease and insomnia. The study included an exploratory evaluation of a consumer-grade wearable "watch" device for assessing sleep that we report on here. Participants who met diagnostic criteria for both probable Alzheimer's disease dementia and insomnia were randomized to suvorexant 10-20 mg (N = 142) or placebo (N = 143) in a double-blind, 4-week trial. Patients were provided with a consumer-grade wearable watch device (Garmin vívosmart^® HR) to be worn continuously. Overnight sleep laboratory PSG was performed on three nights: screening, baseline and Night 29 (last dose). Watch treatment effects were assessed by change-from-baseline in watch TST at Week 4 (average TST per night). We also analysed Night 29 data only, with watch data restricted to the PSG recording time. In the 193 participants included in the Week 4 watch analysis (suvorexant = 97, placebo = 96), the suvorexant-placebo difference in watch TST was 4 min (p = .622). In patients with usable data for both assessments at the baseline and Night 29 PSG (suvorexant = 57, placebo = 50), the watch overestimated TST compared to PSG (e.g., placebo baseline = 412 min for watch and 265 min for PSG) and underestimated change-from-baseline treatment effects: the suvorexant-placebo difference was 20 min for watch TST (p = .405) and 35 min for PSG TST (p = .057). These findings show that the watch was less sensitive than PSG for evaluating treatment effects on TST.

Syndrome of inappropriate antidiuretic hormone secretion induced by suvorexant: a case report

NONE

Syndrome of inappropriate antidiuretic hormone release (SIADH) can sometimes be caused by an adverse effect of certain psychotropic drugs. However, suvorexant has never been reported to cause SIADH. A 77-year-old man with type 2 diabetes was admitted to the Jichi Medical University Hospital for the treatment of major depression. During the treatment, he was prescribed suvorexant for insomnia. Twelve days after the initiation of suvorexant, he developed hyponatremia, which met the diagnostic criteria of SIADH. We suspected the hyponatremia to be an adverse drug effect of suvorexant because no other cause for SIADH was detected. Accordingly, suvorexant was discontinued 15 days after the onset of SIADH, and hyponatremia improved in 6 days. Although suvorexant has fewer adverse drug reactions and is considered relatively safe, clinicians should be aware of the possibility of SIADH induced by suvorexant.

Magnetic Resonance Spectroscopy in the Ventral Tegmental Area Distinguishes Responders to Suvorexant Prior to Treatment: A 4-Week Prospective Cohort Study

Background: The ventral tegmental area (VTA; a dopaminergic nucleus) plays an important role in the sleep-wake regulation system including orexin system. In addition to neuronal activity, there is increasing evidence for an important role of glial cells (i.e., astrocytes and microglia) in these systems. The present study examined the utility of magnetic resonance spectroscopy (MRS) for detecting neural and/or glial changes in the VTA to distinguish responders from non-responders before treatment with the orexin receptor antagonist suvorexant. Methods: A total of 50 patients were screened and 9 patients were excluded. The remaining 41 patients with insomnia who have or not a psychiatric disease who were expected to receive suvorexant treatment were included in this study. We compared MRS signals in the VTA between responders to suvorexant and non-responders before suvorexant use. Based on previous reports, suvorexant responders were defined as patients who improved ≥3 points on the Pittsburgh Sleep Quality Index after 4 weeks of suvorexant use. MRS data included choline (reflects non-specific cell membrane breakdown, including of glial cells) and N-acetylaspartate (a decrease reflects neuronal degeneration). Results: Among 41 examined patients, 20 patients responded to suvorexant and 21 patients did not. By MRS, the choline/creatine and phosphorylcreatine ratio in the VTA was significantly high in non-responders compared with responders (p = 0.039) before suvorexant treatment. There was no difference in the N-acetylaspartate/creatine and phosphorylcreatine ratio (p = 0.297) between the two groups. Conclusions: Changes in glial viability in the VTA might be used to distinguish responders to suvorexant from non-responders before starting treatment. These findings may help with more appropriate selection of patients for suvorexant treatment in clinical practice. Further, we provide novel possible evidence for a relationship between glial changes in the VTA and the orexin system, which may aid in the development of new hypnotics focusing on the VTA and/or glial cells.

[Association Suvorexant and Ramelteon Use with the Risk of Falling: A Retrospective Case-control Study]

Sedative hypnotics are among the classes of drugs reported to influence falls. However, the effects of the sedative hypnotic drugs, suvorexant and ramelteon, on falls are not well known. Therefore, we conducted this retrospective case-control study to examine the association of the use of these two sedative hypnotics with the risk of falls. Conducted at the Sapporo Medical University Hospital in Japan, our study included 360 patients with fall incidents and 819 randomly selected control patients. Patients in the fall group were significantly older with a lower body mass index, and had a history of falls, disabilities in activities of daily living, cognitive impairment, and delirium. Monovariate analysis revealed that patients in the fall group frequently used ramelteon [odds ratio (OR) 2.38, 95% confidence interval (CI): 1.49-3.81, p<0.001], but rarely used suvorexant (OR 0.66, 95% CI: 0.29-1.39, p=0.317), compared with control patients. Furthermore, multivariate analysis revealed that ramelteon use did not increase the risk of falls (adjusted OR 1.43, 95% CI: 0.82-2.48, p=0.207), whereas suvorexant use significantly decreased the risk of falls (adjusted OR 0.32, 95% CI: 0.13-0.76, p=0.009). Although ramelteon tends to be used in patients at a high risk of falls, it may not increase the risk of falls. In contrast, the use of suvorexant may reduce the risk of falls.

Suvorexant for the prevention of delirium: A meta-analysis

BACKGROUND

Delirium is a frequently encountered complication, which is associated with increased mortality. Suvorexant, an approved agent for the treatment of insomnia, is recently suggested to be also effective for prevention of delirium by some authors. However, a consensus has yet to be reached. The goal of this study was to perform a meta-analysis to overall estimate the effectiveness of suvorexant in preventing delirium and its related consequences.

METHODS

Eligible studies were identified by searching online databases of PubMed, EMBASE, and Cochrane Library. The pooled OR was calculated for binary outcomes (e.g., the incidence of delirium, mortality, or adverse events), while standardized mean difference (SMD) were expressed for continuous outcomes (e.g., time to delirium onset, length of stay in hospital and ICU, time on ventilation).

RESULTS

Seven studies which comprised 402 suvorexant treatment patients and 487 patients with control treatment were included in this meta-analysis. Overall, pooled analysis indicated the incidence of delirium could be significantly reduced (OR, 0.30; P < .001) and time to delirium onset was significantly lengthened (SMD, 0.44; P = .006) in patients undergoing suvorexant treatment compared with controls. Suvorexant had no beneficial effects on the secondary outcomes [length of stay in hospital (SMD, -0.65; P = .161) and ICU (SMD, 0.34; P = .297), time on ventilation (SMD, 1.09; P = .318), drug-related adverse events (OR, drug-related adverse events (OR, 1.66; P = .319) and mortality (OR, 2.21; P = .261)]. Subgroup analysis also confirmed the benefit of suvorexant on the development of delirium, which was significant in any subgroup.

CONCLUSION

Suvorexant should be recommended for the prevention of delirium in clinic.

Effect of suvorexant on event-related oscillations and EEG sleep in rats exposed to chronic intermittent ethanol vapor and protracted withdrawal

STUDY OBJECTIVES

Insomnia is a prominent complaint in patients with alcohol use disorders (AUD). However, despite the importance of sleep in the maintenance of sobriety, treatment options for sleep disturbance associated with a history of AUD are currently limited. Recent clinical trials have demonstrated that suvorexant, a dual Hct/OX receptor antagonist, normalizes sleep in patients with primary insomnia; yet, its potential for the treatment of sleep pathology associated with AUD has not been investigated in either preclinical or clinical studies.

METHODS

This study employed a model whereby ethanol vapor exposure or control conditions were administered for 8 weeks to adult rats. Waking event-related oscillations (EROs) and EEG sleep were evaluated at baseline before exposure and again following 24 hr of withdrawal from the exposure. Subsequently, the ability of vehicle (VEH) and two doses (10, 30 mg/kg IP) of suvorexant to modify EROs, sleep, and the sleep EEG was investigated.

RESULTS

After 24 hr following EtOH withdrawal, the ethanol-treated group had increases in waking ERO θ and β activity, more fragmented sleep (shorter duration and increased frequency of slow wave (SW) and rapid eye movement [REM] sleep episodes), and increased θ and β power in REM and SW sleep. Suvorexant induced a dose-dependent decrease in the latency to REM and SW sleep onsets but also produced REM and SW sleep fragmentation and increased β energy in waking EROs when compared with VEH.

CONCLUSIONS

Taken together, these studies suggest that suvorexant has overall sleep-promoting effects, but it may exacerbate some aspects of sleep and EEG pathology.

Sleep and pain in humans with fibromyalgia and comorbid insomnia: double-blind, crossover study of suvorexant 20 mg versus placebo

STUDY OBJECTIVES

The chronic pain disorder, fibromyalgia, is associated with sleep disturbance, typically sleep maintenance. No studies have evaluated the effect of sleep medication on pain sensitivity in this population. Suvorexant, an orexin antagonist approved for treatment of insomnia, was evaluated for effects on both sleep and the pain of fibromyalgia.

METHODS

Women age 21 to 65 years with fibromyalgia and comorbid insomnia (n = 10) were treated, double-blind, for 9 nights each with suvorexant, 20 mg and placebo in counterbalanced order. All were in good psychiatric and stable physical health and met American College of Rheumatology 2010 criteria for fibromyalgia and Diagnostic and Statistical Manual for Mental Disorders, Fifth Edition criteria for insomnia. Screening 8-hour polysomnography (PSG) was used to rule out other sleep disorders. On nights 8 and 9 of each treatment 8-hour PSG were collected and on days 1 and 8 pain sensitivity was assessed at 1100 and 1500 hours by measuring finger withdrawal latency (FWL) to a radiant heat stimulus at 5 randomly presented intensity levels.

RESULTS

Suvorexant versus placebo increased total sleep time (7.2 versus 6.7 hours, P < .05) and reduced wake after sleep onset (37 versus 67 minutes, P < .04) with no night effects or interaction. Latency to persistent sleep and sleep stage measures were not altered. FWL on both am and pm tests varied as a function of intensity (P < .001). Average FWL (over 5 intensities and both days) was increased relative to placebo on both the am (13.9 versus 13.1 seconds) and pm tests (15.8 versus 14.1 seconds, P < .03) following suvorexant the previous night.

CONCLUSIONS

Suvorexant 20 mg in patients with fibromyalgia, improved sleep time and reduced next-day pain sensitivity on assessments of FWL to a radiant heat stimulus.

CLINICAL TRIAL REGISTRY

Registry: ClinicalTrials.gov; Name: A double-blind cross-over, study to compare the hypnotic, daytime sleepiness/fatigue, and pain effects of nighttime administration of suvorexant 20 mg versus placebo in patients with fibromyalgia and comorbid insomnia; Identifier: NCT02684136; URL: https://clinicaltrials.gov/ct2/show/NCT02684136.

Real-world evidence of the safety and efficacy profile of suvorexant in elderly patients with insomnia: a sub-analysis of the post-marketing drug-use results survey in Japan

Objective: Global Phase III trials of suvorexant showed no obvious differences in the safety and efficacy profile of suvorexant between elderly and non-elderly patients. However, the clinical profile of suvorexant in elderly patients with comorbidities in a real-world setting was not evaluated. To further understand the safety and efficacy profile of suvorexant in elderly patients with insomnia in a daily clinical practice setting, we conducted a sub-group analysis of the post-marketing drug-use results survey.Methods: Patients with insomnia who were treated with suvorexant for the first time were divided into three groups: group-1 (<65 years, N = 1490), group-2 (≥65 years and <75 years, N = 730), and group-3 (≥75 years, N = 1028).Results: The incidence of overall adverse drug reactions (ADRs) were 11.28% (N = 168), 8.63% (N = 63), and 8.17% (N = 84) in group-1, -2, and -3, respectively. The ADRs most commonly observed in this survey were somnolence, insomnia, and dizziness, with no new safety concerns or differences in safety issues found. The numbers of patients in group-1, -2, and -3 who visited internal medicine departments were: 690 patients (46.3%), 521 patients (71.4%), and 793 patients (77.1%), respectively. The percentage of patients who were deemed to have "improved", based on the patient's self-assessment and their physician's assessment, was 70-75% of patients in all groups.Conclusion: These results reveal the safety and efficacy profile of suvorexant in elderly patients who often have various and multiple comorbidities and were treated in a daily clinical practice setting.

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.

Hypnotics with novel modes of action

Insomnia and, more generally, lack of sleep are on the rise. Traditionally treated by classical hypnotics, such as benzodiazepines and Z drugs, which both act on the GABA_A receptor, and other modalities, including nondrug therapies, such as cognitive behavioural therapy, there is a range of new hypnotics which are being developed or have recently received market approval. Suvorexant and the like target the orexin/hypocretin system: they should have less side effects in terms of drug-drug interactions with e.g. alcohol, less memory impairment and dependence potential compared to classical hypnotics.

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.

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.

Suvorexant for insomnia in patients with psychiatric disorder: A 1-week, open-label study

Aim

There have been no previous reports on the efficacy and safety of suvorexant for insomnia in people with psychiatric disorders.

Methods

This one‐week, prospective, single‐arm, clinical trial of fixed dose of suvorexant (20 mg if ages 18–64 or 15 mg if age ≥ 65 years) for insomnia included 57 patients with psychiatric disorders who had experienced any of the following insomnia symptoms for four or more nights during the week prior to the start of the study: total sleep time (TST) <6 hours, time to sleep onset (TSO) ≥30 minutes, or two or more episodes of wake after sleep onset.

Results

The mean age of the patients was 49.4 ± 17.3 years; 54.4% were women, 49.1% had a major depressive disorder, and 77.2% completed the trial. Compared with the baseline scores (the mean scores for the two days before the start of the study), taking suvorexant was associated with significant improvements in TST, TSO, wake time after sleep onset, and the patients' sleep satisfaction level at week 1. Adverse events included at least one adverse event (43.9%), sleepiness (28.8%), fatigue (11.5%), nightmares (5.8%), headache (3.8%), dizziness (3.8%), and vomiting (1.9%).

Conclusion

Suvorexant was beneficial for the treatment of insomnia in people with psychiatric disorders. However, this study was of short duration and included only a relatively small number of patients. A larger, long‐term study is needed to investigate the efficacy and safety of suvorexant for insomnia in people with psychiatric disorders.

This is one‐week, prospective, single‐arm, clinical trial of fixed dose of suvorexant for insomnia included 57 patients with psychiatric disorders. Compared with the baseline scores, taking suvorexant was associated with significant improvements in total sleep time, time to sleep onset, wake time after sleep onset, and the patients' sleep satisfaction level at week 1.

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.

Investigation of New Orexin 2 Receptor Modulators Using In Silico and In Vitro Methods

The neuropeptides, orexin A and orexin B (also known as hypocretins), are produced in hypothalamic neurons and belong to ligands for orphan G protein-coupled receptors. Generally, the primary role of orexins is to act as excitatory neurotransmitters and regulate the sleep process. Lack of orexins may lead to sleep disorder narcolepsy in mice, dogs, and humans. Narcolepsy is a neurological disorder of alertness characterized by a decrease of ability to manage sleep-wake cycles, excessive daytime sleepiness, and other symptoms, such as cataplexy, vivid hallucinations, and paralysis. Thus, the discovery of orexin receptors, modulators, and their causal implication in narcolepsy is the most important advance in sleep-research. The presented work is focused on the evaluation of compounds L1–L11 selected by structure-based virtual screening for their ability to modulate orexin receptor type 2 (OX2R) in comparison with standard agonist orexin-A together with their blood-brain barrier permeability and cytotoxicity. We can conclude that the studied compounds possess an affinity towards the OX2R. However, the compounds do not have intrinsic activity and act as the antagonists of this receptor. It was shown that L4 was the most potent antagonistic ligand to orexin A and displayed an IC₅₀ of 2.2 µM, offering some promise mainly for the treatment of insomnia.

Addition of Suvorexant to Ramelteon Therapy for Improved Sleep Quality with Reduced Delirium Risk in Acute Stroke Patients

BACKGROUND AND PURPOSE

Delirium in acute stroke is associated with poor clinical outcome. The purpose of this study was to examine the effect of sleep medications on sleep quality and delirium in acute stroke.

METHODS

In this retrospective cohort study, sleep disturbances, and delirium were investigated in acute stroke patients treated in April 2013-March 2017 who were prescribed ramelteon plus either an alpha-aminobutyric acid receptor (GABAR) agonist or a selective dual orexin receptor antagonist (suvorexant).

RESULTS

Of the patients included, 104 received a GABAR agonist and 128 received suvorexant in addition to ramelteon. Patient characteristics did not differ significantly between the groups, except for a higher proportion of cerebral infarction in suvorexant group (P = .033). Subjective sleep quality was significantly improved in suvorexant group compared to GABAR agonist group (difficulty staying asleep: 6.3% versus 34%, P < .001; daytime sleepiness: 33% versus 63%, P < .001). Delirium was significantly less frequent in suvorexant group than GABAR agonist group (7.0% versus 31%, P < .001). The length of hospital stay was significantly shorter in suvorexant group than in GABAR agonist group (in days, 21 [15-29] versus 25 [18-33]; P = .019). Multivariable logistic regression analysis revealed that the addition of suvorexant was significantly associated with a reduced occurrence of delirium (odds ratios .19, 95% confidence interval .085-.43, P < .001).

CONCLUSIONS

Addition of suvorexant to ramelteon therapy, rather than a GABA receptor agonist, can improve subjective sleep quality without inducing delirium in acute stroke patients.

Ability of suvorexant to prevent delirium in patients in the intensive care unit: a randomized controlled trial

Aim

There are no effective, tolerable, and established medications for preventing delirium in critically ill patients admitted to the intensive care unit (ICU). We investigated whether suvorexant was effective in preventing ICU delirium.

Methods

This randomized controlled study evaluated 70 adult patients (age ≥20 years) admitted to the mixed medical ICU of the Tokyo Medical University Hospital (Tokyo, Japan) between May 2015 and February 2017. Patients were randomized using a sealed envelope method to receive either suvorexant (n = 34; 15 mg for elderly patients and 20 mg for younger adults) or conventional treatment (n = 36) for a 7-day period. The primary outcome was delirium incidence based on the definition in the 5th edition of the Diagnostic and Statistical Manual of Mental Disorders.

Results

No significant between-group differences were observed in the demographic or clinical characteristics. Kaplan-Meier estimates revealed that time to delirium onset was significantly longer in the suvorexant group than in the conventional group (P < 0.05).

Conclusion

Suvorexant might be effective in preventing delirium in ICU patients.

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.