Drugs for insomnia.

INTRODUCTION: Sleep is a vital neurochemical process involving sleep-promoting and arousal centers in the brain. Insomnia is a pervasive disorder characterized by difficulties in initiating or maintaining or non-refreshing (poor quality) sleep and clinically significant daytime distress. Insomnia is more prevalent in women and old age and puts sufferers at significant physical and mental health risks. This review summarizes published data on the current and emerging insomnia drug classes, rationale for development and associated risks/benefits. (Summary of Product Characteristics and Medline search on "hypnotic" or specific drug names and "Insomnia"). AREAS COVERED: GABA(A) receptor modulators facilitate sleep onset and some improve maintenance but increase risk of dependence, memory, cognitive and psychomotor impairments, falls, accidents and mortality. Melatonin receptor agonists improve quality of sleep and/or sleep onset but response may develop over several days. They have more benign safety profiles and are indicated for milder insomnia, longer usage and (prolonged release melatonin) older patients. Histamine H-1 receptor antagonists improve sleep maintenance but their effects on cognition, memory and falls remain to be demonstrated. Late-stage pipeline orexin OX1/OX2 and serotonin 5HT2A receptor antagonists may hold the potential to address several unmet needs in insomnia pharmacotherapy but safety issues cast some doubts over their future. EXPERT OPINION: Current and new insomnia drugs in the pipeline target different sleep regulating mechanisms and symptoms and have different tolerability profiles. Drug selection would ideally be based on improvement in the quality of patients' sleep, overall quality of life and functional status weighed against risk to the individual and public health.

Effects of prolonged-release melatonin and zolpidem on postural stability in older adults.

OBJECTIVES: A prolonged-release formulation of melatonin (PR-M) is indicated for insomnia in patients aged 55 years and older. Because hypnotics result in impairments of body sway, it was important to evaluate the effect of 2 mg PR-M on postural stability in older adults at night. METHODS: Twenty-four healthy volunteers (12 women, 12 men, aged 55-64 years) completed a randomized, double-blind, single-dose, three-way crossover study of postural stability of PR-M 2 mg, zolpidem 10 mg (active control) or placebo. Subjects were tested for body sway 30 min before, 1.5 and 4 h after dosing. Parameters tested were the area of the 95% confidence ellipse enclosing the center of pressure (COP; [A95]) and COP path length. RESULTS: Zolpidem significantly increased the A95 (both eyes conditions at all time points) and path length of COP. PR-M had no effect on A95 (both "eyes closed" and "eyes open" conditions at all time points) compared with placebo and increased COP path length by 10% at 4 h post-dose in open but not closed eyes condition. No serious adverse events were observed. CONCLUSIONS: In older adults, evening PR-M intake did not impair postural stability during the night. The postural instability with zolpidem demonstrated assay sensitivity and validated the outcome.

Assessing the potential for drug interactions and long term safety of melatonin for the treatment of insomnia in children with autism spectrum disorder.

INTRODUCTION: Melatonin preparations are emerging first-line pharmacotherapy for insomnia in children and adolescents with autism spectrum disorder (ASD), but quality, formulation, consistency, dosing, and limited long-term safety data are of concern. The recent approval of pediatric-appropriate prolonged-release melatonin (Ped-PRM) addresses these aspects. AREAS COVERED: A systematic search of PubMed and web of science for prospective, randomized, and controlled trials (RCTs) of melatonin preparations vs placebo in children and adolescents with ASD and the European public assessment report on Ped-PRM was conducted. EXPERT OPINION: Melatonin is rapidly absorbed and undergoes first pass hepatic metabolism by cytochrome CYP1A2; over 80% is excreted in the urine as 6-sulfatoxymelatonin (inactive). Immediate-release melatonin (IRM) is short-acting (3-4 h), whereas PRM provides therapeutic levels throughout the night. Drugs interacting with CYP1A2 are likely to slow-down melatonin metabolism. High variability in bioavailability among subjects calls for dose optimization. Melatonin was essentially safe for short-term use (up to 3 months). Long-term data available for Ped-PRM demonstrate fatigue (6.3%), somnolence (6.3%), and mood swings (4.2%) with no evidence of effects on height, BMI, or pubertal development, tolerance or withdrawal effects following long-term use of this product. Studies on long-term safety of IRM and oversight of melatonin supplement manufacture are warranted.

Melatonin and mental capacities in newborn infants.

OBJECTIVES: To investigate the role of melatonin in the emergence of mental capacities in the newborn infant. STUDY DESIGN: Assessment of Preterm Infant Behavior examination was performed at 2 weeks post-term age for 39 (21 preterm and 18 term) infants. 6-Suphatoxymelatonin from nocturnal urine samples was analyzed by enzyme-linked immunosorbent assays, and the Mental Developmental Index, assessed by Bayley scales, was correlated at 4, 6, and 9 months' corrected age. RESULTS: Multivariate analysis of variance with repeated measures showed that improved autonomic function at 2 weeks of age was associated with higher Mental Developmental Index scores at 9 months when related to the amount of melatonin at 4, 6, and 9 months of age. CONCLUSIONS: Early compromised autonomic system function in preterm infants is associated with lower mental capacities and is related to lower melatonin levels at later ages.

Sleep, Growth, and Puberty After 2 Years of Prolonged-Release Melatonin in Children With Autism Spectrum Disorder.

OBJECTIVE: A recent 3-month double-blind, placebo-controlled study demonstrated efficacy and safety of pediatric prolonged-release melatonin (PedPRM) for insomnia in children with autism spectrum disorder. This study examined the long-term effects of PedPRM treatment on sleep, growth, body mass index, and pubertal development. METHOD: Eighty children and adolescents (2-17.5 years of age; 96% with autism spectrum disorder) who completed the double-blind, placebo-controlled trial were given 2 mg, 5 mg, or 10 mg PedPRM nightly up to 104 weeks, followed by a 2-week placebo period to assess withdrawal effects. RESULTS: Improvements in child sleep disturbance and caregiver satisfaction with child sleep patterns, quality of sleep, and quality of life were maintained throughout the 104-week treatment period (p < .001 versus baseline for all). During the 2-week withdrawal placebo period, measures declined compared with the treatment period but were still improved compared with baseline. PedPRM was generally safe; the most frequent treatment-related adverse events were fatigue (6.3%), somnolence (6.3%), and mood swings (4.2%). Changes in mean weight, height, body mass index, and pubertal status (Tanner staging done by a physician) were within normal ranges for age with no evidence of delay in body mass index or pubertal development. CONCLUSION: Nightly PedPRM at optimal dose (2, 5, or 10 mg nightly) is safe and effective for long-term treatment in children and adolescents with autism spectrum disorder and insomnia. There were no observed detrimental effects on children's growth and pubertal development and no withdrawal or safety issues related to the use or discontinuation of the drug. CLINICAL TRIAL REGISTRATION INFORMATION: Efficacy and Safety of Circadin in the Treatment of Sleep Disturbances in Children With Neurodevelopment Disabilities; https://clinicaltrials.gov/; NCT01906866.

VEGF up-regulation by G93A superoxide dismutase and the role of malate-aspartate shuttle inhibition.

A gain of interaction of the amyotrophic lateral sclerosis (ALS)-linked G93A-superoxide dismutase-1 (G93A-hSOD1) with cytosolic malate dehydrogenase (cytMDH), a key enzyme in the malate-aspartate shuttle, diverts neurons towards anaerobic metabolism. Changes in vascular endothelial growth factor (VEGF) are reported in ALS and hypoxia. Here we report that expression of G93A-hSOD1 fused with green fluorescent protein in NSC-34 cells enhanced VEGF expression and levels of VEGF and its upstream regulator hypoxia-inducible factor (HIF-1alpha). G93A-hSOD1 expressing cells were unable to further up-regulated VEGF in response to Co(2+) and H(2)O(2). Amino-oxyacetate that inhibits the malate-aspartate shuttle caused a similar increase in VEGF mRNA and impaired response to H(2)O(2) in WT-hSOD1 expressing cells. Interruption of the G93A-hSOD1/cytMDH interaction reduced VEGF expression in G93A-hSOD1 expressing cells and restored their ability to up-regulate VEGF in response to Co(2+) and H(2)O(2). These results demonstrate that the ALS-linked G93A hSOD1 mutation impairs VEGF regulation compatible with the inhibition of neuronal malate-aspartate shuttle.

Nightly treatment of primary insomnia with prolonged release melatonin for 6 months: a randomized placebo controlled trial on age and endogenous melatonin as predictors of efficacy and safety.

BACKGROUND: Melatonin is extensively used in the USA in a non-regulated manner for sleep disorders. Prolonged release melatonin (PRM) is licensed in Europe and other countries for the short term treatment of primary insomnia in patients aged 55 years and over. However, a clear definition of the target patient population and well-controlled studies of long-term efficacy and safety are lacking. It is known that melatonin production declines with age. Some young insomnia patients also may have low melatonin levels. The study investigated whether older age or low melatonin excretion is a better predictor of response to PRM, whether the efficacy observed in short-term studies is sustained during continued treatment and the long term safety of such treatment. METHODS: Adult outpatients (791, aged 18-80 years) with primary insomnia, were treated with placebo (2 weeks) and then randomized, double-blind to 3 weeks with PRM or placebo nightly. PRM patients continued whereas placebo completers were re-randomized 1:1 to PRM or placebo for 26 weeks with 2 weeks of single-blind placebo run-out. Main outcome measures were sleep latency derived from a sleep diary, Pittsburgh Sleep Quality Index (PSQI), Quality of Life (World Health Organzaton-5) Clinical Global Impression of Improvement (CGI-I) and adverse effects and vital signs recorded at each visit. RESULTS: On the primary efficacy variable, sleep latency, the effects of PRM (3 weeks) in patients with low endogenous melatonin (6-sulphatoxymelatonin [6-SMT]

Physiological effects of melatonin: role of melatonin receptors and signal transduction pathways.

Melatonin, an endogenous signal of darkness, is an important component of the body's internal time-keeping system. As such it regulates major physiological processes including the sleep wake cycle, pubertal development and seasonal adaptation. In addition to its relevant antioxidant activity, melatonin exerts many of its physiological actions by interacting with membrane MT1 and MT2 receptors and intracellular proteins such as quinone reductase 2, calmodulin, calreticulin and tubulin. Here we review the current knowledge about the properties and signaling of melatonin receptors as well as their potential role in health and some diseases. Melatonin MT1 and MT2 receptors are G protein coupled receptors which are expressed in various parts of the CNS (suprachiasmatic nuclei, hippocampus, cerebellar cortex, prefrontal cortex, basal ganglia, substantia nigra, ventral tegmental area, nucleus accumbens and retinal horizontal, amacrine and ganglion cells) and in peripheral organs (blood vessels, mammary gland, gastrointestinal tract, liver, kidney and bladder, ovary, testis, prostate, skin and the immune system). Melatonin receptors mediate a plethora of intracellular effects depending on the cellular milieu. These effects comprise changes in intracellular cyclic nucleotides (cAMP, cGMP) and calcium levels, activation of certain protein kinase C subtypes, intracellular localization of steroid hormone receptors and regulation of G protein signaling proteins. There are circadian variations in melatonin receptors and responses. Alterations in melatonin receptor expression as well as changes in endogenous melatonin production have been shown in circadian rhythm sleep disorders, Alzheimer's and Parkinson's diseases, glaucoma, depressive disorder, breast and prostate cancer, hepatoma and melanoma. This paper reviews the evidence concerning melatonin receptors and signal transduction pathways in various organs. It further considers their relevance to circadian physiology and pathogenesis of certain human diseases, with a focus on the brain, the cardiovascular and immune systems, and cancer.

Late evening brain activation patterns and their relation to the internal biological time, melatonin, and homeostatic sleep debt.

Sleep propensity increases sharply at night. Some evidence implicates the pineal hormone melatonin in this process. Using functional magnetic resonance imaging, brain activation during a visual search task was examined at 22:00 h (when endogenous melatonin levels normally increase). The relationships between brain activation, endogenous melatonin (measured in saliva), and self-reported fatigue were assessed. Finally, the effects of exogenous melatonin administered at 22:00 h were studied in a double blind, placebo-controlled crossover manner. We show that brain activation patterns as well as the response to exogenous melatonin significantly differ at night from those seen in afternoon hours. Thus, activation in the rostro-medial and lateral aspects of the occipital cortex and the thalamus diminished at 22:00 h. Activation in the right parietal cortex increased at night and correlated with individual fatigue levels, whereas exogenous melatonin given at 22:00 h reduced activation in this area. The right dorsolateral prefrontal cortex, an area considered to reflect homeostatic sleep debt, demonstrated increased activation at 22:00 h. Surprisingly, this increase correlated with endogenous melatonin. These results demonstrate and partially differentiate circadian effects (whether mediated by melatonin or not) and homeostatic sleep debt modulation of human brain activity associated with everyday fatigue at night.

[Controlled release melatonin (Circadin) in the treatment of insomnia in older patients: efficacy and safety in patients with history of use and non-use of hypnotic drugs].

Circadin is a prolonged-release 2 mg melatonin formulation which, when taken before bedtime, mimics the physiological pattern of the endogenous hormone excreted during the night. It was approved by the EU-EMEA in June 2007 for the short-term treatment of primary insomnia characterized by poor quality of sleep in patients aged 55 or over. Placebo controlled clinical trials demonstrated, beyond the shortening of sleep Latency seen with traditional hypnotics, concomitant improvements in sleep quality and next day alertness and subsequently, quality of life. In contrast to traditional sedative hypnotics, Circadin has shown no evidence of impairing cognitive and psychomotor skills, of rebound, dependence or abuse potential and no significant adverse events compared to placebo. It can be used concomitantly with most medications but may potentiate the effects of GABA-A receptor modulators. Analyses presented here show that Circadin has comparable efficacy and safety in patients with and without history of hypnotic drug use.

Pediatric Prolonged-Release Melatonin for Sleep in Children with Autism Spectrum Disorder: Impact on Child Behavior and Caregiver's Quality of Life.

A randomized, 13-weeks, placebo-controlled double-blind study in 125 subjects aged 2-17.5 years with Autism Spectrum Disorder or Smith-Magenis syndrome and insomnia demonstrated efficacy and safety of easily-swallowed prolonged-release melatonin mini-tablets (PedPRM; 2-5 mg) in improving sleep duration and onset. Treatment effects on child behavior and caregiver's quality of life were evaluated. PedPRM treatment resulted in significant improvement in externalizing but not internalizing behavior (Strengths and Difficulties questionnaire; SDQ) compared to placebo (p = 0.021) with clinically-relevant improvements in 53.7% of PedPRM-treated versus 27.6% of placebo-treated subjects (p = 0.008). Caregivers' quality of life also improved with PedPRM versus placebo (p = 0.010) and correlated with the change in total SDQ (p = 0.0005). PedPRM alleviates insomnia-related difficulties, particularly externalizing behavior in the children, subsequently improving caregivers' quality of life.

Alternative splicing of neurexins: a role for neuronal polypyrimidine tract binding protein.

Neurexins are polymorphic synaptic membrane proteins generated by alternative splicing of transcripts from six promoters in three genes (two promoters in each gene) at five canonical sites. Neurexins and factors regulating their alternative splicing may orchestrate coordinated presynaptic and postsynaptic development. Bioinformatic analysis revealed several sequence elements that could be involved in the regulation of alternative splicing at splice site 4 (SS#4); among them elements suspected as intronic binding sites of polypyrimidine tract binding protein (PTB), and its neuron specific analog nPTB. The role of nPTB in neurexin-2alpha and beta SS#4 splicing were studied using small interfering RNA (siRNA) to silence nPTB expression. Transformed rat retinal ganglion (RGC-5) cells expressed nPTB, PTB and neurexin-2alpha (mostly exon 20 excluded form) but not neurexin-2beta. Mouse spinal-cord glioma hybrid (NSC-34) cells expressed nPTB, PTB and both neurexin-2alpha and beta (mostly exon 20 included form). nPTB-siRNA inhibited nPTB but not PTB expression and significantly enhanced neurexin-2alpha SS# 4 exon-excluded transcript in both cell types. Neurexin-2beta SS#4 splicing was not affected by nPTB-siRNA. These results show a role for nPTB in neurexin-2alpha alternative splicing. The differential enhancement of SS# 4 exon exclusion in neurexin-2alpha suggests that the effects of nPTB are mediated via additional site(s) present in neurexin-2alpha but not in the shorter, beta form.

New perspectives on the role of melatonin in human sleep, circadian rhythms and their regulation.

In mammals, a central circadian clock, located in the suprachiasmatic nuclei (SCN) of the hypothalamus, tunes the innate circadian physiological rhythms to the ambient 24 h light-dark cycle to invigorate and optimize the internal temporal order. The SCN-activated, light-inhibited production of melatonin conveys the message of darkness to the clock and induces night-state physiological functions, for example, sleep/wake blood pressure and metabolism. Clinically meaningful effects of melatonin treatment have been demonstrated in placebo-controlled trials in humans, particularly in disorders associated with diminished or misaligned melatonin rhythms, for example, circadian rhythm-related sleep disorders, jet lag and shift work, insomnia in children with neurodevelopmental disorders, poor (non-restorative) sleep quality, non-dipping nocturnal blood pressure (nocturnal hypertension) and Alzheimer's disease (AD). The diminished production of melatonin at the very early stages of AD, the role of melatonin in the restorative value of sleep (perceived sleep quality) and its sleep-anticipating effects resulting in attenuated activation of certain brain networks are gaining a new perspective as the role of poor sleep quality in the build-up of ß amyloid, particularly in the precuneus, is unravelled. As a result of the recently discovered relationship between circadian clock, sleep and neurodegeneration, new prospects of using melatonin for early intervention, to promote healthy physical and mental ageing, are of prime interest in view of the emerging link to the aetiology of Alzheimer's disease. LINKED ARTICLES: This article is part of a themed section on Recent Developments in Research of Melatonin and its Potential Therapeutic Applications. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.16/issuetoc.

Long-Term Efficacy and Safety of Pediatric Prolonged-Release Melatonin for Insomnia in Children with Autism Spectrum Disorder.

Objective: A recent double-blind randomized placebo-controlled study demonstrated 3-month efficacy and safety of a novel pediatric-appropriate prolonged-release melatonin (PedPRM) for insomnia in children and adolescents with autism spectrum disorder (ASD) and neurogenetic disorders (NGD) with/without attention-deficit/hyperactivity disorder comorbidity. Long-term efficacy and safety of PedPRM treatment was studied. Methods: A prospective, open-label efficacy and safety follow-up of nightly 2, 5, or 10 mg PedPRM in subjects who completed the 13-week double-blind trial (51 PedPRM; 44 placebo). Measures included caregiver-reported Sleep and Nap Diary, Composite Sleep Disturbance Index (CSDI), caregiver's Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale, and quality of life (WHO-5 Well-Being Index). Results: Ninety-five subjects (74.7% males; mean [standard deviation] age, 9 [4.24]; range, 2-17.5 years) received PedPRM (2/5 mg) according to the double-blind phase dose, for 39 weeks with optional dose adjustment (2, 5, or 10 mg/day) after the first 13 weeks. After 52 weeks of continuous treatment (PedPRM-randomized group) subjects slept (mean [SE]) 62.08 (21.5) minutes longer (p = 0.007); fell asleep 48.6 (10.2) minutes faster (p < 0.001); had 89.1 (25.5) minutes longer uninterrupted sleep episodes (p = 0.001); 0.41 (0.12) less nightly awakenings (>50% decrease; p = 0.001); and better sleep quality (p < 0.001) compared with baseline. The placebo-randomized group also improved with PedPRM. Altogether, by the end of 39-week follow-up, regardless of randomization assignment, 55/72 (76%) of completers achieved overall improvement of ≥1 hour in total sleep time (TST), sleep latency or both, over baseline, with no evidence of decreased efficacy. In parallel, CSDI child sleep disturbance and caregivers' satisfaction of their child's sleep patterns (p < 0.001 for both), PSQI global (p < 0.001), and WHO-5 (p = 0.001) improved in statistically significant and clinically relevant manner (n = 72) compared with baseline. PedPRM was generally safe; most frequent treatment-related adverse events were fatigue (5.3%) and mood swings (3.2% of patients). Conclusion: PedPRM, an easily swallowed formulation shown to be efficacious versus placebo, is an efficacious and safe option for long-term treatment (up to 52 weeks reported here) of children with ASD and NGD who suffer from insomnia and subsequently improves caregivers' quality of life.

Gi and RGS proteins provide biochemical control of androgen receptor nuclear exclusion.

Nuclear localization of androgen receptors (ARs) is essential for their activity. Melatonin induces AR nuclear exclusion via increase in cGMP, calcium, and protein kinase C (PKC) activation, presumably through G-protein(s). The effects of regulators of G-protein signaling (RGS) on AR localization were studied in AR-expressing PC3 cells. Gi-specific RGS10 inhibited melatonin but not cGMP-induced AR nuclear exclusion, independent of androgen. No evidence for Gq activation by melatonin was found. However, Gi/Gq-selective RGS4 inhibited AR nuclear exclusion downstream of PKC activation--an effect that was abrogated by constitutively active Gq. RGS10 and RGS4, but not RGS2, ablated the inhibitory effects of melatonin on AR reporter gene activity. For the first time, these data show regulation by Gi and Gi-specific RGS protein-mediated AR nuclear exclusion, which is potentially important in the treatment of AR-dependent cancers and neurodegenerative disorders. They also reveal a role for a Gq protein downstream of PKC activation in AR nuclear localization.

CD44 Splice Variants as Potential Players in Alzheimer's Disease Pathology.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by cognitive deficits, deposition of amyloid-ß (Aß) plaques, intracellular neurofibrillary tangles, and neuronal cell death. Neuroinflammation is commonly believed to participate in AD pathogenesis. CD44 is an inflammation-related gene encoding a widely-distributed family of alternatively spliced cell surface glycoproteins that have been implicated in inflammation, metastases, and inflammation-linked neuronal injuries. Here we investigated the expression patterns of CD44S (which does not contain any alternative exon) and CD44 splice variants in postmortem hippocampal samples from AD patients and matched non-AD controls. The expression of CD44S and CD44 splice variants CD44V3, CD44V6, and CD44V10 was significantly higher in AD patients compared to non-AD controls. Immunohistochemistry of human hippocampal sections revealed that CD44S differentially localized to neuritic plaques and astrocytes, whereas CD44V3, CD44V6, and CD44V10 expression was mostly neuronal. Consistent with these findings, we found that the expression of CD44V6 and CD44V10 was induced by Aß peptide in neuroblastoma cells and primary neurons. Furthermore, in loss of function studies we found that both CD44V10-specific siRNA and CD44V10 antibody protected neuronal cells from Aß-induced toxicity, suggesting a causal relationship between CD44V10 and neuronal cell death. These data indicate that certain CD44 splice variants contribute to AD pathology and that CD44V10 inhibition may serve as a new neuroprotective treatment strategy for this disease.

Current Phase II investigational therapies for insomnia.

INTRODUCTION: Insomnia is typified by a difficulty in sleep initiation, maintenance and/or quality (non-restorative sleep) resulting in significant daytime distress. AREAS COVERED: This review summarizes the available efficacy and safety data for drugs currently in the pipeline for treating insomnia. Specifically, the authors performed MEDLINE and internet searches using the keywords 'Phase II' and 'insomnia'. The drugs covered target GABAA (zaleplon-CR, lorediplon, EVT-201), orexin (filorexant, MIN-202), histamine-H1 (LY2624803), serotonin 5-HT2A (ITI-007), melatonin/serotonin5-HT1A (piromelatine) and melatonin (indication expansions of prolonged-release melatonin and tasimelteon for pediatric sleep and circadian rhythm disorders) receptors. EXPERT OPINION: Low-priced generic environments and high development costs limit the further development of drugs that treat insomnia. However, the bidirectional link between sleep and certain comorbidities may encourage development of specific drugs for comorbid insomnia. New insomnia therapies will most likely move away from GABAAR receptors' modulation to more subtle neurological pathways that regulate the sleep-wake cycle.

Lasting treatment effects in a postmarketing surveillance study of prolonged-release melatonin.

Surveillance studies are useful to evaluate how a new medicinal product performs in everyday treatment and how the patient who takes it feels and functions, thereby determining the benefit/risk ratio of the drug under real-life conditions. Prolonged-release melatonin (PRM; Circadin) was approved in Europe for the management of primary insomnia patients age 55 years or older suffering from poor quality of sleep. With traditional hypnotics (e.g. benzodiazepine-receptor agonists), there are concerns about rebound insomnia and/or withdrawal symptoms. We report data from a postmarketing surveillance study in Germany on the effects of 3 weeks of treatment with PRM on sleep in patients with insomnia during treatment and at early (1-2 days) and late (around 2 weeks) withdrawal. In total, 653 patients (597 evaluable) were recruited at 204 sites (mean age 62.7 years, 68% previously treated with hypnotics, 65% women). With PRM treatment, the mean sleep quality (on a scale of 1-5 on which 1 is very good and 5 is very bad) improved from 4.2 to 2.6 and morning alertness improved from 4.0 to 2.5. The improvements persisted over the post-treatment observation period. Rebound insomnia, defined as a one-point deterioration in sleep quality below baseline values, was found in 3.2% (early withdrawal) and 2.0% (late withdrawal). Most of the patients (77%) who used traditional hypnotics before PRM treatment had stopped using them and only 5.6% of naive patients started such drugs after PRM discontinuation. PRM was well tolerated during treatment and the most frequently reported adverse events were nausea (10 patients, 1.5%), dizziness, restlessness and headache (five patients each, <1%). There were no serious adverse events and no adverse events were reported after discontinuation. The persisting treatment effect and very low rebound rate suggest a beneficial role of sleep-wake cycle stabilization with PRM in the treatment of insomnia.

Prolonged release melatonin for improving sleep in totally blind subjects: a pilot placebo-controlled multicenter trial.

INTRODUCTION: Melatonin, secreted by the pineal gland during the night phase, is a regulator of the biological clock and sleep tendency. Totally blind subjects frequently report severe, periodic sleep problems, with 50%-75% of cases displaying non-24-hour sleep-wake disorder (N24HSWD) due to inability to synchronize with the environmental day-night cycle. Melatonin immediate-release preparations are reportedly effective in N24HSWD. Here, we studied the efficacy and safety of prolonged-release melatonin (PRM), a registered drug for insomnia, for sleep disorders in totally blind subjects living in normal social environments. The primary endpoint was demonstration of clinically meaningful effects on sleep duration (upper confidence interval [CI] limit >20 minutes whether significant or not) to allow early decision-making on further drug development in this indication. TRIAL REGISTRATION: ClinicalTrials.gov registry - NCT00972075. METHODS: In a randomized, double-blind, placebo-controlled proof-of-principle study, 13 totally blind subjects had 2 weeks' placebo run-in, 6 weeks' randomized (1:1) PRM (Circadin(®)) or placebo nightly, and 2 weeks' placebo run-out. Outcome measures included daily voice recorded sleep diary, Clinical Global Impression of Change (CGIC), WHO-Five Well-being Index (WHO-5), and safety. RESULTS: Mean nightly sleep duration improved by 43 minutes in the PRM and 16 minutes in the placebo group (mean difference: 27 minutes, 95% CI: -14.4 to 69 minutes; P=0.18; effect size: 0.82) meeting the primary endpoint. Mean sleep latency decreased by 29 minutes with PRM over placebo (P=0.13; effect size: 0.92) and nap duration decreased in the PRM but not placebo group. The variability in sleep onset/offset and latency tended to decrease during PRM but not placebo treatment. The potentially beneficial effects of PRM persisted during the 2 weeks of discontinuation period, consistent with clock stabilizing effects. PRM was well-tolerated, adverse events were of mild or moderate severity and similar between PRM and placebo. CONCLUSION: Nightly use of PRM may potentially improve patient-reported sleep difficulties in totally blind individuals trying to adhere to normal social lifestyle. A larger study powered to demonstrate a statistically significant effect is warranted.