The purpose of this study is to investigate the effects of CYP3A4/5 inhibitor or inducer on the pharmacokinetics of KW-6356 when CYP3A4/5 inhibitor or inducer is orally administered to healthy Japanese men for 7 days.

Inclusion Criteria:

1. Subjects having issued written consent to this study at their own discretion
2. Japanese men aged 20 to 44 years at the time of informed consent
3. Subjects with BMI ≥18.5 and <25.0 at screening
4. Subjects with screening results of; resting pulse rate: 40 to 100 bpm, systolic blood pressure: 90 to 139 mmHg, diastolic blood pressure: 40 to 89 mmHg

Exclusion Criteria:

1. Subjects with any current disease requiring treatment
2. Subjects having drug allergy or its history
3. Subjects having psychiatric disease or its history
4. Positive results for any of the following infection-related items examined at screening: hepatitis B surface (HBs) antigen, HBs antibody, hepatitis B core (HBc) antibody, hepatitis C virus (HCV) antibody, human immunodeficiency virus (HIV) antigen/antibody, human T-lymphotropic virus (HTLV)-1 antibody, rapid plasma reagin (PRP) test, or Treponema pallidum (TP) antibody.
5. Subjects with clinically significant abnormality detected on 12-lead electrocardiogram (ECG) recorded prior to the first administration of investigational product.
6. Subjects categorized as patients listed in the warnings or contraindications section of the package insert of the perpetrator drug.
7. Subjects having used any drug (including over-the-counter [OTC] drugs, topical agents, vitamin preparations, health supplements, and Chinese herbal medicines) within 2 weeks prior to the first administration of investigational product.
8. Subjects having consumed grapefruit (including any food or beverage containing grapefruit) or any food or beverage containing St John's wort within 1 week prior to the first administration of investigational product.
9. Subjects having smoked or used smoking cessation agents (including chewing or eating of nicotine-containing products and application of nicotine patches) within 4 weeks prior to the first administration of investigational product.
10. Subjects having received inpatient treatment or surgery within 12 weeks prior to the first administration of investigational product.
11. Subjects having participated in a clinical study of a pharmaceutical product or a medical device or any equivalent study and used the investigational product or the unapproved medical device within 4 months prior to the first administration of investigational product.
12. Subjects having undergone ≥400 mL of blood collection within 12 weeks prior to the first administration of investigational product or ≥200 mL of blood collection within 4 weeks prior to the first administration of investigational product (for blood donation or clinical trial, etc.) or pheresis donation (plateletpheresis or plasmapheresis donation) within 2 weeks prior to the first administration of investigational product.
13. Subjects having issued no consent to adoption of any appropriate contraceptive method during the period from day of admission to 12 weeks after the final administration of the perpetrator drug. The appropriate contraceptive method is defined as sexual abstinence or use of 2 of the following contraceptive devices: condom, oral contraceptives, intrauterine device, and pessary.
14. Subjects having received KW-6356 before.
15. Other subjects unsuitable for participating in the study in the opinion of the investigator or subinvestigator.