title: Melatonin agonist tasimelteon (VEC-162) for transient insomnia after sleep-time shift: two randomised controlled multicentre trials.
abstract: BACKGROUND
  Circadian rhythm sleep disorders are common causes of insomnia for millions of individuals. We did a phase II study to establish efficacy and physiological mechanism, and a phase III study to confirm efficacy of the melatonin agonist tasimelteon (VEC-162) for treatment of transient insomnia associated with shifted sleep and wake time.
  
  
  METHODS
  We undertook phase II and phase III randomised, double-blind, placebo-controlled, parallel-group studies. In a phase II study, 39 healthy individuals from two US sites were randomly assigned to tasimelteon (10 [n=9], 20 [n=8], 50 [n=7], or 100 mg [n=7]) or placebo (n=8). We monitored individuals for 7 nights: 3 at baseline, 3 after a 5-h advance of sleep-wake schedule with treatment before sleep, and 1 after treatment; we measured plasma melatonin concentration for circadian phase assessment. In a phase III study, 411 healthy individuals from 19 US sites, who had transient insomnia induced in a sleep clinic by a 5-h advance of the sleep-wake schedule and a first-night effect in a sleep clinic, were given tasimelteon (20 [n=100], 50 [n=102], or 100 mg [n=106]) or placebo (n=103) 30 min before bedtime. Prespecified primary efficacy outcomes were polysomnographic sleep efficiency (phase II study), latency to persistent sleep (phase III study), and circadian phase shifting (phase II study). Analysis was by intention to treat. Safety was assessed in both studies. These trials are registered with ClinicalTrials.gov, numbers NCT00490945 and NCT00291187.
  
  
  RESULTS
  In the phase II study, tasimelteon reduced sleep latency and increased sleep efficiency compared with placebo. The shift in plasma melatonin rhythm to an earlier hour was dose dependent. In the phase III study, tasimelteon improved sleep latency, sleep efficiency, and wake after sleep onset (ie, sleep maintenance). The frequency of adverse events was similar between tasimelteon and placebo.
  
  
  CONCLUSIONS
  After an abrupt advance in sleep time, tasimelteon improved sleep initiation and maintenance concurrently with a shift in endogenous circadian rhythms. Tasimelteon may have therapeutic potential for transient insomnia in circadian rhythm sleep disorders.
authors.affiliation: Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA.
authors.forename: Shantha Mw
authors.initials: SM
authors.lastname: Rajaratnam
authors.forename: Mihael H
authors.initials: MH
authors.lastname: Polymeropoulos
authors.forename: Dennis M
authors.initials: DM
authors.lastname: Fisher
authors.forename: Thomas
authors.initials: T
authors.lastname: Roth
authors.forename: Christin
authors.initials: C
authors.lastname: Scott
authors.forename: Gunther
authors.initials: G
authors.lastname: Birznieks
authors.forename: Elizabeth B
authors.initials: EB
authors.lastname: Klerman
mesh_terms: D000293:Adolescent; D002940:Circadian Rhythm / Q000187:drug effects*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008550:Melatonin / Q000819:agonists* / Q000097:blood*; D008875:Middle Aged; D017286:Polysomnography; D012890:Sleep / Q000187:drug effects*; D007319:Sleep Initiation and Maintenance Disorders / Q000188:drug therapy* / Q000209:etiology; D013997:Time Factors; D055815:Young Adult
chemical_list: D008550:Melatonin