A Phase 4 Study to Evaluate Pharmacokinetics and Safety of Darunavir Along With Ritonavir in Healthy Male Japanese Participants

The purpose of this study is to evaluate the pharmacokinetics (explores what the body does to the drug) and safety of darunavir, and will be administered in combination with Ritonavir in healthy adult Japanese male participants.

This is an open-label (all people know the identity of the intervention), single oral-dose and post-marketing study of darunavir administered in combination with low-dose ritonavir in healthy adult Japanese male participants. The total study duration will be approximately of 14 days per participant. The study consists of 3 parts: Screening (that is, 28 days before study commences on Day 1); Treatment (that is, Day 1-5); and Follow-up (that is, up to Day 13). The participants will be hospitalized for 6 nights and 7 days. All the eligible participants will receive Darunavir oral tablet on Day 3 and ritonavir capsule orally twice daily from Day 1-5. Participants will keep upright position until 4 hours after study drug administration. Both the drugs will be administered within 15 minutes after completion of meal. Blood samples will be collected for evaluation of pharmacokinetics at pre-dose and post-dose of study treatment. Participants' safety will be monitored throughout the study.

Eligibility Criteria:
Inclusion Criteria:

* Male Participants provided with sufficient explanation of the investigational product, the drugs to be provided and this clinical study prior to the start of participation in the clinical study, and capable of providing voluntary informed consent in writing
* Male Participants with a Body Mass Index (BMI) between 18.5 and 25.0 kilogram per square meter (kg/m\^2) at the time of the Screening tests
* Non-smokers or male participants who are capable of abstaining from smoking during the period from the day before the Screening tests until the completion of the post-treatment examinations
* Male Participants consenting to use a medically-approved contraceptive method (such as condoms or the like) during the period from hospital admission until the completion of the post-treatment examinations
* Male Participants showing no clinically significant abnormalities at the time of Screening, on the day prior

Exclusion Criteria:

* Participants suffering or with a history of diseases related to the liver, kidneys, circulatory system, respiratory system, digestive system, neuropsychiatric system, hematopoietic function or endocrine function and who may be inappropriate for participation in this clinical study
* Participants who participated in another clinical study and were treated with another investigational product within 120 days prior to the start of the initial dosing of the provided drugs
* Participants giving 200 milliliter (mL) or more of blood within 30 days prior to the start of the initial dosing of the provided drugs or giving 400 mL or more of blood within 90 days prior to the start of the initial dosing of the provided drugs (such as blood donation), or giving a total of 1200 mL or more of blood within the past year
* Participants with a history of hypersensitivity to sulfonamide drugs, drug allergies or drug hypersensitivity, alcohol, pharmaceutical or drug addiction, or who may be addicted
* Participants with positive results for Human Immunodeficiency Virus antigen or antibodies, Hepatitis C Virus antibodies, Hepatitis B Surface antigen or the serological test for syphilis