The objective of the current study is to investigate the effect of multiple oral daily doses of BI 201335 on the steady-state pharmacokinetics of darunavir co-administered with ritonavir.

Inclusion criteria:

1. Healthy male and female subjects according to the following criteria: medical history, physical examination, vital signs (blood pressure, pulse rate), 12-lead electrocardiogram (ECG), clinical laboratory tests
2. Age 18 to 55 years (incl.)
3. Body Mass Index (BMI) 18.5 to 29.9 kg/m2 (incl.) and weight greater than 50 kg
4. Signed and dated written informed consent prior to admission to the study in accordance with Good Clinical Practice (GCP) and the local legislation.

Exclusion criteria:

1. Any finding of the medical examination (including blood pressure (BP), pulse rate (PR) and ECG) deviating from normal and of clinical relevance
2. Any evidence of a clinically relevant concomitant disease
3. Gastrointestinal, hepatic, renal, respiratory, cardiovascular, metabolic, immunological or hormonal disorders
4. History of photosensitivity or recurrent rash.
5. Surgery of the gastrointestinal tract (except appendectomy)
6. Diseases of the central nervous system (such as epilepsy) or psychiatric disorders or neurological disorders
7. History of relevant orthostatic hypotension, fainting spells or blackouts.
8. Chronic or relevant acute infections
9. History of relevant allergy/hypersensitivity (including allergy to drug or its excipients)
10. Intake of drugs with a long half-life (more than 24 hours) within at least one month or less than 10 half-lives of the respective drug prior to administration or during the trial
11. Participation in another trial with an investigational drug within two months prior to administration or during the trial
12. Smoker (more than 10 cigarettes)
13. Inability to refrain from smoking on trial days
14. Alcohol abuse (more than 30 g/day)
15. Drug abuse
16. Blood donation (more than 100 mL within four weeks prior to administration or during the trial)
17. ALT outside the normal range or any other laboratory value outside the reference range that is of clinical relevance
18. Inability to comply with dietary regimen of trial site
19. The subject is not able to understand and comply with protocol requirements, instructions and protocol-stated restrictions
20. Positive serology tests for Human immunodeficiency virus (HIV) and hepatitis B / C virus
21. Vulnerable subjects (e.g. persons kept in detention)