Ritonavir-boosted tipranavir demonstrates superior efficacy to ritonavir-boosted protease inhibitors in treatment-experienced HIV-infected patients: 24-week results of the RESIST-2 trial

BACKGROUND: Tipranavir, a novel protease inhibitor, has demonstrated antiviral activity against protease inhibitor-resistant human immunodeficiency virus type 1 (HIV-1) isolates. The Randomized Evaluation of Strategic Intervention in multi-drug reSistant patients with Tipranavir (RESIST-2) trial is an ongoing, open-label, phase III trial comparing ritonavir-boosted tipranavir (TPV/r) plus an optimized background regimen with an individually optimized, ritonavir-boosted protease inhibitor in treatment-experienced, HIV-1-infected patients.

METHODS: Patients at 171 sites in Europe and Latin America who had received > or = 2 previous protease inhibitor regimens, had triple-antiretroviral class experience, had an HIV-1 RNA level > or = 1000 copies/mL, and had genotypically demonstrated primary protease inhibitor resistance were eligible. After genotypic resistance tests were performed, a protease inhibitor and optimized background regimen were selected before randomization. Patients were randomized to receive either TPV/r or comparator protease inhibitor-ritonavir (CPI/r) and were stratified on the basis of preselected protease inhibitor and enfuvirtide use. Treatment response was defined as a confirmed HIV-1 load reduction > or = 1 log10 less than the baseline value without a treatment change at week 24.

RESULTS: A total of 863 patients were randomized and treated. At baseline, the mean HIV-1 load was 4.73 log10 copies/mL, and the mean CD4+ cell count was 218 cells/mm3. The preplanned 24-week efficacy analyses of 539 patients demonstrated treatment response rates of 41% in the TPV/r arm and 14.9% in the CPI/r arm (intent-to-treat analysis; P<.0001). The mean CD4+ cell count increased by 51 cells/mm3 in the TPV/r arm and by 18 cells/mm3 in the CPI/r arm. The most common adverse events were mild-to-moderate diarrhea, nausea, and headache. Grade 3 or greater elevations in serum transaminase, cholesterol, and triglyceride levels were more frequent in the TPV/r arm.

CONCLUSIONS: TPV/r had superior antiviral activity and increased immunologic benefits, compared with CPI/r, at week 24 among treatment-experienced patients infected with multidrug-resistant HIV-1.