This randomized, open-label, multiple-treatment multiple-dose, 2-period, 2-sequence study
will evaluate potential drug-drug interactions between danoprevir (DNV) when coadministered
with low-dose ritonavir (r) and tenofovir disoproxil fumarate (TDF) or atazanavir (ATZ) in
healthy volunteers. Subjects will be randomized to receive in Period 1 either single oral
doses of TDF and multiple oral doses of DNV/r or multiple oral doses of ATZ/r. In Period 2,
all subjects will receive multiple oral doses of DNV/r plus ATZ. Anticipated time on study
treatment is up to 20 days.