 The purpose of this Phase II, open-label, roll-over trial is to evaluate the long term safety and tolerability of TMC125, administered as part of an individually optimized antiretroviral therapy, in HIV 1 infected subjects. In addition, the antiviral activity and immunological effect of TMC125 as part of an antiretroviral regimen over time, and the evolution of HIV phenotype and genotype will be evaluated. Subjects who were randomized to an active control arm of any sponsor-selected TMC125 trial and virologically failed or completed the entire treatment period, or to placebo arm and were treated for at least 48 and who may derive benefit from TMC125 treatment as judged by the investigator can be enrolled. Based on the currently selected studies, a maximum of 170 subjects will be enrolled in the current trial. A dose of 800mg b.i.d . of TMC125 formulation TF035 and after the formulation switch, 200mg b.i.d. formulation F060, will be given in combination with an investigator-selected, optimized underlying therapy starting at baseline and consisting of at least 2 drugs nucleoside reverse transcriptase inhibitors NRTIs andor allowed protease inhibitors PIs andor enfuvirtide T 20 for 48 weeks. Tolerability and safety will be assessed throughout the trial. The efficacy parameters will be determined at defined time points during the trial. The trial will involve a screening visit preferable on the same day as the withdrawal visit of the sponsor-selected trial, a baseline visit, a treatment period of 48 weeks, a final visit and a 4 week follow-up period. TMC125, 800 mg twice a day and after formulation switch, at 200 mg twice a day 