Efficacy and Safety of Eplivanserin Treatment for Sleep Maintenance Insomnia Followed by Optional Extension up to 1 Year

Inclusion Criteria: * Out patients * Each patient must have primary insomnia in accordance with DSM-IV-TR-Axis I criteria * Based on patient's information, the patient has spent at least 6.5 hours and not more than 9.0 hours, in bed, each night, over the preceding two weeks. * Based on patient's information, the patient must complain of at least one hour of wakefulness after sleep onset for at least 3 nights per week over the preceding month * Patient must report impact daytime functioning associated with sleep maintenance insomnia as measured by question 3 of Insomnia Severity Index at screening visit and randomization visit. Exclusion Criteria: * Females who are lactating or pregnant * Woman of childbearing potential with a positive serum beta human chorionic gonadotropin pregnancy test at screening and not using an acceptable form of contraception * Patients presenting with acute or chronic pain resulting in insomnia * Patients with history of epilepsy or seizures * Consumption of xanthine containing beverage (i.e. tea, coffee, or cola) comprising more than 5 glasses/day * Evidence of any clinically significant, severe, or unstable acute or chronically progressive medical or surgical disorder which may affect patient safety * BMI \>32 * Acute or chronic pain resulting in insomnia * Patients with current psychiatric disorders according to DSM-IV-TR criteria, mental retardation, or dementia * Clinically significant and abnormal EKG (QTc interval \>500 msec) * Positive for hepatitis B or C * Serious head injury or stroke within 1 year * Use of OTC medications such as valerian root, kava, melatonin, St. John's Wort, or alluna; prescription sleep medications or anxiolytics within 1 week or 5 half-lives * Participation in another trial within two month before the screening visit * Use of any substance with psychotropic effects or properties known to affect sleep/wake * Unable to complete the study questionnaires * Night shift workers, and individuals who nap 3 or more times per week over the preceding month * History of: * Primary hypersomnia * Narcolepsy * Breathing-related sleep disorder (such as sleep apnea) * Circadian rhythm sleep disorder * Parasomnia (somnambulism) * Dyssomnia (such as periodic leg movements)