The purpose of this study is research with the goal of evaluating the effect of TMC125 (a non-nucleoside reverse transcriptase inhibitor) on slowing down the growth of the HIV virus. The study will also investigate whether this new medication is well tolerated, and to further confirm that the medication is safe to be used.
Inclusion Criteria: * Patient has 3 or more primary protease inhibitor mutations * documented genotypic evidence of resistance to currently available NNRTIs by having at least 1 NNRTI (non-nucleoside reverse transcriptase inhibitors) resistance-associated mutation * on a stable antiretroviral therapy for at least 8 weeks * plasma viral load at screening visit \> 5000 HIV-1 RNA copies/mL. Exclusion Criteria: * Active AIDS defining illnesses (except for stable, cutaneous Kaposi's Sarcoma or wasting syndrome) * Any grade 3 or grade 4 toxicity according to the DAIDS grading scale * Use of disallowed concurrent therapy * Any active clinically significant disease