This study will be a single-center, single dose, randomized, double-blind, placebo-controlled study in healthy Japanese male subjects. The study will consist of 2 parts: Part A (young subjects) and Part B (elderly subjects). In Part A sequential cohorts of subjects will be treated with single ascending doses of E2307. The maximum tolerated dose (MTD) will be determined in Part A. Part B will be initiated after Part A is completed. In Part B one cohort of healthy elderly subjects will be treated with a single dose of E2307 at one dose level below the MTD. In part A, a total of 56 subjects will be enrolled into 7 cohorts sequentially and randomized 3:1 to receive either E2307 (1 mg, 3 mg, 10 mg, 30 mg, 100 mg, 200 mg, or 300 mg) or placebo. In part B, a total of 8 subjects will be randomized, 6 subjects to a single dose of E2307 and 2 subjects to placebo.

Inclusion Criteria:

Parts A and B

1. Provide written informed consent

2. Willing and able to comply with all aspects of the protocol

   Part A: Young cohort

3. Non-smoking, male subjects age >=20 years and less than 55 years old at the time of informed consent

   Part B: Elderly Cohort

4. Non-smoking, male subjects age >=65 years and less than 85 years old at the time of informed consent

Exclusion Criteria:

Subjects who meet any of the following criteria will be excluded from this study:

1. Clinically significant illness that requires medical treatment within 8 weeks or a clinically significant infection that requires medical treatment within 4 weeks of dosing
2. Any history of abdominal surgery that may affect PK profiles of E2307 (eg. hepatectomy, nephrectomy, digestive organ resection)
3. Known history of clinically significant drug allergy (at Screening)