In antiretroviral experienced patients Study 045 is a randomised, multicenter trial comparing REYATAZ (300 mg once daily) with ritonavir (100 mg once daily) to REYATAZ (400 mg once daily) with saquinavir soft gelatine capsules (1,200 mg once daily), and to lopinavir + ritonavir (400/ 100 mg fixed dose combination twice daily), each in combination with tenofovir (see sections 4.5 and 4.8) and one NRTI, in 347 (of 358 randomised) patients with virologic failure on two or more prior regimens containing at least one PI, NRTI, and NNRTI.