This phase 1, randomized, open-label, multiple-dose, 2-sequence, 2-period crossover study
will evaluate potential drug-drug interaction between efavirenz and danoprevir with low-dose
ritonavir in healthy volunteers. In Period 1. subjects will be randomized to receive multiple
oral doses of either danoprevir with ritonavir or efavirenz for 14 days. In Period 2, all
subjects will receive multiple oral doses of the combination danoprevir with ritonavir and
efavirenz for 14 days. Anticipated time on study treatment is 28 days.