The purpose of this study is to evaluate the antiviral activity as measured by the change in viral load from baseline in the 14 days following initiation of treatment with 4 different dose regimens of TMC310911 co-administered with ritonavir.

This is an open-label (all people know the identity of the intervention) and randomized (study medication assigned by chance) study in treatment-naive human immunodeficiency virus type 1 (HIV-1)-infected participants (participants who had not been treated with a therapeutic HIV vaccine within 1 year prior to enrollment and who had never been treated with an antiretroviral [ARV] medication indicated for the treatment of HIV-infection or ARVs for treatment of hepatitis B infection with anti-HIV activity prior to screening). In this study approximately 32 participants will be enrolled and randomly assigned to receive 4 different dose regimens co-administered with ritonavir (8 participants in each dosing regimen). The trial will consist of a screening period (maximum 6 weeks), a treatment period with TMC310911 (2 weeks), and a follow-up period (4 weeks). Safety evaluation will include assessment of adverse events, clinical laboratory tests, vital sign measurements, physical examinations and electrocardiograms.

Inclusion Criteria:

• Documented human immunodeficiency virus type 1 (HIV-1) infection for at least 6 months prior to the screening date
• Participant who has not been treated with a therapeutic HIV vaccine within 1 year prior to enrolment and has never been treated with an antiretroviral (ARV) medication indicated for the treatment of HIV infection or ARVs for treatment of hepatitis B-infection with anti-HIV activity
• Participant agrees not to start antiretroviral therapy (ART) before the baseline visit
• Able to comply with the protocol requirements and have good accessible veins
• HIV-1 plasma viral load at screening visit of above 5,000 HIV-1 Ribonucleic acid copies/mL
• CD4+ cell count above 200 cells/mm3 at screening

Exclusion Criteria:

• HIV-2 infected participants and/or participants with any active or chronic hepato-renal disease
• Life expectancy of less than 6 months
• Documented acute (primary) HIV-1 infection
• Pre-existing protease inhibitor (PI) medication resistance
• Any currently active Acquired Immunodeficiency Syndrome (AIDS) - defining illness
• Any active clinically significant disease or findings during screening or medical history or physical examination that in the investigator's opinion, would compromise the outcome of the study
• Any confirmed grade 3 or 4 toxicity according to the Division of AIDS (DAIDS) grading scale at screening