TMC125 is a nonnucleoside reverse transcriptase inhibitor with an EC50 of 1.4 to 4.3 nM for wild-type HIV-1. Additionally, TMC125 is highly potent against a wide range of single-mutant and double-mutant NNRTI-resistant HIV-1 strains, including L100I, K103N, Y181C, and L100I+K103N, at EC50s of 3, 1, 7, and 19 nM, respectively. (1)

TMC125 is believed to have a high barrier to development of resistance in vitro based on multiplicity of infection experiments which confirm a profile distinct from other reverse transcriptase inhibitors. (2)