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Abstract:

Objectives: The SWAN study compared the efficacy and safety of switching to an ATV-containing regimen versus continuing unmodified ARV regimen (control) in subjects on stable PI ± ritonavir (RTV)-containing HAART. Methods: In this Phase IIIb, 48 week, multicenter, open-label, randomized, prospective study, PI-treated subjects with no previous PI virologic failure and HIV-1 RNA <50 c/mL, were randomized 2:1 to either switch PI(s) to ATV vs control. Primary endpoint: proportion of viral rebounds (VReb) (confirmed ³50 c/mL) at 48 weeks. Results: 407 subjects were treated (274 ATV, 133 control). Baseline median CD4 cell count was 490 cells/mm3. 54% used boosted PIs at screening (lopinavir/RTV 37%). Mean time (months) on prior ARV: 40.3 PI, 46.7 NRTI, 16.0 NNRTI. ... Gastrointestinal symptoms were reported in 8% of subjects on ATV vs 13% on control, with less use of antidiarrheals observed in the ATV arm (p<0.05). Improvements in all lipid fractions were observed in the ATV arm (non-HDL-C ¯18% vs ¯3%; p<0.0001). Rates of grade 3/4 ALT elevations were comparable overall (4% vs 6%) and in subjects with hepatitis C and/or B co-infection (14% vs 16%). Reports of SAEs were 10% vs 6%, with all 5 deaths in the control arm (4%). Comparable rates of discontinuation (14% vs 19%), or discontinuation for AEs (6% both) were reported (1% of ATV subjects discontinued for scleral icterus/jaundice). Conclusion: Patients on boosted/unboosted PIs who switched to an ATV-containing regimen had significantly fewer episodes of viral rebound than patients who continued their prior PI treatment and maintained viral suppression for 48 weeks. In addition, patients switched to ATV had less use of antidiarrheals and significant improvement in plasma lipids.