An Study to Determine the Bioavailability of E2609 Tablets Compared to Capsules and the Effect of Food on Absorption

1. Caucasian males defined as persons of a European or Latin American descent
2. Healthy male 30 to 55 years inclusive at the time of informed consent
3. Body mass index (BMI) of 18 to 32 kg/m2 at Screening
4. Subjects must have had a successful vasectomy (confirmed azoospermia), or they and their female partners must not be of childbearing potential or must be practicing highly effective contraception throughout the study period and for 30 days after study drug discontinuation. No sperm donation is allowed during the study period and for 30 days after study drug discontinuation.

Exclusion Criteria

1. Any history of seizures or epilepsy (not including a history of simple febrile seizures in childhood) or disturbance of consciousness likely to be due to seizures
2. Any medical condition which, in the opinion of the investigator has high risk of seizures (e.g., history of traumatic brain injury associated with loss of consciousness or amnesia, alcohol abuse, substance abuse) at Screening or within past 5 years
3. Any history of cerebrovascular disease (stroke or transient ischemic attack)
4. A history of prolonged QT/QTc interval or prolonged period from the beginning of the QRS complex to the end of the T wave on an ECG (QT)/ QT corrected for heart rate using Fridericia?s formula (QTcF) interval (QTcF > 450 ms) as demonstrated by the mean of triplicate electrocardiogram (ECGs) (recorded at least 1 min apart) at Screening or Baseline Period
5. Any other clinically significant ECG abnormalities at Screening or Baseline Periods, e.g. component of the ECG cycle from onset of atrial depolarization to onset of ventricular depolarization (PR)>220 ms, component of ECG wave representing ventricular depolarization (QRS)>110 ms
6. Hypersensitivity to the study drugs or any of their excipients