Clinical Trials


Blind Individuals with Recurrent Sleep
Problems Needed for Clinical Research Study
and Survey

Individuals who are totally blind with recurring sleeping or napping problems are needed to answer a survey and/or take part in a clinical research study.

For each completed survey, $25 will be donated to organizations that support people with blindness.

Eligible volunteers who take part in the clinical research study will be compensated for their time and will receive all study-related investigational medication, medical evaluation and transportation at no cost.

Sleep problems and napping occur in some individuals who are totally blind. This may be caused by the lack of light needed to reset the "body clock". The result is recurrent sleep problems similar to jet lag.

Eligible volunteers are:

  • between 18 and 75 years old
  • totally blind
  • having recurrent trouble sleeping at night or experience daytime sleepiness or napping

If you are interested, please call toll free 1-888-389-7033

from 9:00 AM to 5:00 PM M-F ET
email, or contact us online at

Clinical Trial Information

Vanda Study 3201 is designed to investigate the efficacy and safety of tasimelteon 20 mg versus placebo in totally blind subjects with Non-24-Hour Disorder (Non-24). Study 3201 is a multicenter, randomized, double-masked, placebo-controlled, parallel study with a target enrollment of 84 individuals. The study includes a 6-month treatment period. Laboratory measures of the synchronization between the internal body clock and the 24-hour environmental light/dark cycle, as well as measures of nighttime and daytime sleep are included.

Multiple study sites throughout the United States and Germany are planned for the study. A list of current study sites is provided below.

The efficacy outcomes to be assessed include urinary 6-sulfatoxymelatonin (aMT6s) assessments, average subjective nighttime total sleep time (nTST), average subjective total daytime sleep duration and clinical global impression of change (CGI-C). The formal objectives are as follows:


The entrainment of the circadian melatonin rhythm as measured by urinary 6-sulfatoxymelatonin(aMT6s)


  • The average of the lower quartile of nights of subjective nighttime total sleep times (nTST)
  • The average of the upper quartile of days of subjective daytime sleep duration
  • The average of subjective nighttime total sleep times (nTST)
  • The average of subjective daytime sleep duration
  • The Clinical Global Impression-Change (CGI-C)


Inclusion Criteria:

  • Informed written consent;
  • 18 years to 75 years;
  • No perception of light by the subject's own report;
  • Diagnosis of N24HD as determined by:
    1. History (within the last 3 months) of trouble sleeping at night (such as difficulty initiating sleep or staying asleep), difficulty awakening in the morning, or daytime sleepiness as determined by answering yes to at least one question in the Sleep Complaint Questionnaire and
    2. Urinary aMT6s demonstrates a progressive delay of the aMT6 acrophase time.
  • Willing and able to comply with study requirements and restrictions including a commitment to a fixed 9-hour sleep opportunity during the study; and
  • Fluent in English.

Exclusion Criteria:

  • Have a probable diagnosis of a current sleep disorder other than N24HD that is the primary cause of the sleep disturbance based on clinical investigator medical judgment;
  • Current clinically significant cardiovascular, respiratory, neurologic, hepatic, hematopoietic, renal, gastrointestinal or metabolic dysfunction unless currently controlled and stable;
  • History (within the 12 months prior to screening) of psychiatric disorders including Major Depressive Disorder, Generalized Anxiety Disorder, Axis II Disorders, delirium or any other psychiatric disorder that in the opinion of the clinical investigator would affect participation in the study or full compliance with study procedures;
  • History of intolerance and/or hypersensitivity to melatonin or melatonin agonists;
  • Worked night, rotating, or split (period of work, followed by break, and then return to work) shift work within 1 month of the screening visit or plan to work these shifts during the study;
  • Unable to perform calls to the study IVR system to report questionnaire results;
  • Exposure to any investigational drug, including placebo, within 30 days or 5 half lives (whichever was longer) of screening;
  • Use of central nervous system prescription or OTC medications that affects the sleep-wake cycle; or
  • Use of melatonin or melatonin agonist.

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