A Study to Assess the Safety and Tolerability of E2511 in Healthy Participants

A Randomized, Double-Blind, Placebo-Controlled, Single Ascending Dose Study to Assess the Safety, Tolerability, and Pharmacokinetics of E2511 in Healthy Subjects

The primary objective of this study is to evaluate the safety, tolerability, and pharmacokinetic (PK) of E2511 following single ascending oral doses in healthy adult and elderly participants.

Inclusion Criteria:

1. Non-smoking, age greater than or equal to (>=) 18 years and less than (<) 55 years old adult male or female (Cohorts 1 - 6) or age >=65 years and less than or equal to (<=) 85 years old elderly male or female (Cohort 7) at the time of informed consent
2. Weight of at least 50 kilogram (kg) and body mass index >=18 and <30 kilogram per square meter (kg/m^2) at Screening

Exclusion Criteria:

1. Males who have not had a successful vasectomy (confirmed azoospermia) or they and their female partners do not meet the criteria (that is, not of childbearing potential or practicing highly effective contraception throughout the study period plus 90 days after study drug discontinuation). No sperm donation is allowed during the study period plus 90 days after discharge from the study.

2. Females who are breastfeeding or pregnant at Screening or Baseline

3. Females of childbearing potential who:

   • Within 28 days before study entry, did not use a highly effective method of contraception,
   • Do not agree to use a highly effective method of contraception (as described above) throughout the entire study period and for 28 days after study drug discontinuation.

4. Clinically significant illness that requires medical treatment within 8 weeks or a clinically significant infection that requires medical treatment within 4 weeks of dosing

5. Evidence of disease that may influence the outcome of the study within 4 weeks before dosing

6. Evidence of disease related to chronic headaches, migraines, joint pain or other disorders or disease resulting in chronic or intermittent pain within 4 weeks before dosing

7. Any personal or family history of seizures (including febrile seizures) or diagnosis of epilepsy or episode of unexplained loss of consciousness

8. Any history of neurological or other medical conditions which in the opinion of the investigator has the potential to reduce seizure threshold

9. Any epileptiform discharges in EEG at Screening

10. A prolonged QT/ QT interval corrected for heart rate (QTc) interval >450 millisecond [ms]) A history of risk factors for torsade de pointes

11. History of prolonged QT/QTc interval

12. Left bundle branch block

13. History of myocardial infarction or active ischemic heart disease

14. History of clinically significant arrhythmia or uncontrolled arrhythmia

15. Any lifetime history of suicidal ideation or any lifetime history of suicidal behavior as indicated by the C-SSRS

16. Any lifetime history of psychiatric disease