The efficacy and safety of the melatonin agonist beta-methyl-6-chloromelatonin in primary insomnia: a randomized, placebo-controlled, crossover clinical trial.

BACKGROUND: While melatonin agonists are known to regulate circadian sleep rhythms, it is not clear whether melatonin agonists have a direct soporific effect. It has been suggested that melatonin's soporific effect is secondary to its ability to induce hypothermia. beta-Methyl-6-chloromelatonin is a high-affinity melatonin receptor agonist that is not associated with hypothermia. The purpose of the present study was to determine if the melatonin agonist beta-methyl-6-chloromelatonin has a direct soporific effect in subjects with primary insomnia. METHOD: A double-blind, placebo-controlled, crossover safety and efficacy study of 20 mg, 50 mg, and 100 mg of beta-methyl-6-chloromelatonin and placebo was conducted in subjects with DSM-IV-TR primary insomnia. Of 84 subjects screened, 40 progressed to randomly receive each of 3 beta-methyl-6-chloromelatonin doses or placebo on each of 2 consecutive nights with 5-day washout periods between treatments. The effect of treatment on both polysomnographic and subjectively measured sleep parameters, next-morning psychomotor performance, and safety measures was determined. The primary outcome measure was latency to persistent sleep measured by polysomnography. RESULTS: A significant effect of beta-methyl-6-chloromelatonin on the primary efficacy variable, latency to persistent sleep, was observed (p = .0003). The 20-mg dose resulted in a significant 31% improvement in sleep latency compared with placebo, while significant 32% and 41% improvements were observed at the 50-mg and 100-mg doses, respectively (20 mg, p = .0082; 50 mg, p = .0062; 100 mg, p < .0001). Similarly, a significant effect of beta-methyl-6-chloromelatonin on subjective measures of time to fall asleep occurred (p = .0050), with significant improvement observed at both the 50-mg and 100-mg doses (p = .0350 and .0198, respectively) and a trend toward improvement observed at the 20-mg dose (p = .0582). Adverse events were mild to moderate in severity and did not differ in frequency between beta-methyl-6-chloromelatonin and placebo treatments. CONCLUSION: beta-Methyl-6-chloromelatonin significantly decreases both objective and subjective measures of sleep latency in subjects with primary insomnia. Thus, these data suggest that mel-atonin agonists may exert a direct soporific effect, as previous research indicates that beta-methyl-6-chloromelatonin is not associated with changes in body temperature, heart rate, or blood pressure.

C-tau biomarker of neuronal damage in severe brain injured patients: association with elevated intracranial pressure and clinical outcome.

Following traumatic brain injury, the neuronally-localized intracellular protein MAP-tau is proteolytically cleaved (C-tau) and gains access to cerebrospinal fluid (CSF) and serum. The present study compared initial CSF C-tau levels, initial Glasgow Coma Scale (GCS) scores and elevated intracranial pressure (ICP) as predictors of clinical outcome. In this preliminary, prospective study of consecutive severe traumatic brain injured patients (TBI) clinical outcome was quantified with the Glasgow Outcome Scale (GOS) at discharge (n=28). Sensitivity and specificity of initial C-tau levels and initial GCS scores as predictors of clinical outcome is reported. To assess disease specificity C-tau levels were compared between TBI patients and neurologic (n=87) and non-neurologic control patients (n=67). Initial CSF C-tau levels were elevated 40,000 fold in TBI patients compared to either neurologic or non-neurologic control patients (P<0.001). Initial C-tau levels were correlated with clinical outcome (P=0.006) and were a significant predictor of dichotomized clinical outcome (P=0.011) demonstrating a sensitivity of prediction of 92% and a specificity of 94%. Initial C-tau levels were also a significant predictor of subsequent ICP with higher initial C-tau levels associated with elevated ICP (P=0.014). Initial GCS score were correlated with clinical outcome (P=0.026) and demonstrated a sensitivity of 50% and a specificity of 100% for predicting dichotomized clinical outcome. Statistical analysis indicated that initial C-tau levels and initial GCS scores were independent predictors of clinical outcome. The present preliminary study demonstrates that initial CSF C-tau levels are a significant predictor of ICP and clinical outcome with particular sensitivity for identifying severe TBI patients with good clinical outcome. Future studies employing a larger sample size and clinical outcome assessment at longer periods after hospitalization will be needed to determine the utility of initial C-tau levels as a clinical biomarker in TBI.