The purpose of this study is to investigate the pharmacokinetic interaction between etravirine and artemether/lumefantrine and darunavir/ritonavir and artemether/lumefantrine in healthy Human Immunodeficiency Virus- (HIV-)negative patients. 'Pharmacokinetic interaction' means that one medication can influence the absorption and elimination from the body of the other medication.

This is a Phase I, partially randomized, open-label, single-center, two-way, two-period cross-over study to investigate the pharmacokinetic interaction between etravirine (ETR) or darunavir/ritonavir (DRV/rtv) and the antimalarial drugs artemether/lumefantrine at steady-state in healthy human immunodeficiency virus (HIV)-negative patients. The study population will consist of 32 healthy patients, equally divided over 2 panels. Patients in Panel 1 will be treated with ETR and artemether/lumefantrine; patients in Panel 2 will be treated with DRV/rtv and artemether/lumefantrine. Treatment A will consist of 3 days of treatment with artemether/lumefantrine. Treatment B will consist of 200 mg ETR twice daily (b.i.d.) (Panel 1) or 600/100 mg DRV/rtv b.i.d. (Panel 2) from Day 1 to Day 21 with a single dose of ETR (Panel 1) or DRV/rtv (Panel 2) in the morning on Day 22. From Day 8, 3 days of treatment with artemether/lumefantrine. In a first stage of treatment in Panel 2, only 4 patients will be allowed to start Treatment B. Based on the ECG results of the first 4 patients with evaluable ECG data after assessments on Day 11 (66 hours after the combined intake of DRV/rtv and artemether/lumefantrine), the Sponsor will decide whether additional patients can be allowed to start Treatment B. There will be a washout period of at least 4 weeks between Treatments A and B. Half of the patients of Panel 1 (8 patients) and Panel 2 (8 patients) will be randomized to sequence AB and half will be randomized to sequence BA. Randomization in Panel 2 will occur in two steps. In Step 1, 4 patients will be allocated to sequence BA and evaluated for QTc prolongation. Based on the outcome of their ECG results, the Sponsor will decide whether the remainder of patients will be randomized in Step 2, i.e. 4 patients to BA and 8 patients to AB (1:2 randomization). Serial pharmacokinetic assessments will be determined for Panels 1 and 2 in Treatments A and B for artemether and its metabolite dihydroartemisinin (DHA) after the first intake of artemether/lumefantrine over 8 hours and after the last intake of artemether/lumefantrine over 72 hours (3 days), and for lumefantrine after the last intake of artemether/lumefantrine over 264 hours (11 days). Serial pharmacokinetic assessments will be determined for ETR (Panel 1) or DRV and rtv (Panel 2) over the 12-hour dosing interval on Day 8 (after the morning intake) and Day 11 (after the last dose of artemether/lumefantrine) of Treatment B. All ETR, DRV/rtv and artemether/lumefantrine treatments will be administered under fed conditions and will be taken within 10 minutes after completion of a meal. Safety and tolerability evaluations will be recorded on an ongoing basis.

Inclusion Criteria:

• if of childbearing potential or if male, use a highly effective method of birth control.
• Able to comply with protocol requirements.
• A BMI (weight in kg divided by the square of height in meters) of 18.5 to 30.0 kg/m2, extremes included.
• healthy on the basis of a medical evaluation
• Non-smoking for at least 3 months prior to selection.

Exclusion Criteria:

• previously demonstrated clinically significant allergy, hypersensitivity or intolerance to any of the investigational medications or its excipients
• Use of concomitant medication, including over-the-counter products and dietary supplements.
• Having participated in more than 1 study (single or multiple dose) with ETR (TMC125), DRV (TMC114), dapivirine (TMC120) and/or rilpivirine (TMC278, formerly known as R278474), or having developed a rash, erythema or urticaria while participating in a study with the aforementioned compounds.
• A positive pregnancy test or breast feeding at screening or on Day 1.
• Any condition that, in the opinion of the investigator, would compromise the study or the well-being of the patient or prevent the patient from meeting or performing study requirements