This is a single-center, randomized, double-blind, placebo-controlled, sequential, multiple-dose study. The study will be conducted in two parts: Part A (6 cohorts of healthy adults receiving evening dosing) and Part B (one cohort of elderly adults receiving evening dosing).

Included:

• Healthy males or females, ages 18 to 55 years (Part A) or 65 to 80 years (Part B)
• Who report typical time in bed 7.5 to 9 hours
• Who report typical bedtime 22:00 - 24:00 and typical wake time 06:00 - 08:00
• Who report typical sleep latency of <= 30 minutes
• All females must be of non-childbearing potential, or subjects who have been sterilized surgically or who are otherwise proven sterile. Females must have a negative serum beta-human chorionic gonadotropin (Beta-hCG) test result at Screening and a negative urine pregnancy test at Baseline.
• Body mass index BMI > 18 and 32 kg/m2 at Screening

Excluded:

• Performed shift work within 2 weeks prior to Screening
• Had taken a flight across three or more time zones in the 7 days prior to Screening
• Female subjects who are nursing
• With a history of gastrointestinal surgery (hepatectomy, nephrectomy, digestive organ resection, etc.) that may affect PK profile of E2006
• With a known history of clinically significant drug or food allergies or presently experiencing significant seasonal allergy
• Hypersensitivity to the study drug or any of the excipients