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SUPPORT: 48-week results of fosamprenavir/ritonavir vs efavirenz with abacavir/lamivudine in under-represented, antiretroviral-naïve patients

Purpose of study

The objective of this study was to evaluate the efficacy, tolerability, and safety of fosamprenavir/ritonavir (FPV/r) versus efavirenz (EFV), both in combination with abacavir/lamivudine (ABC/3TC), in a population that is often underrepresented in U.S. clinical trials.


In this ongoing 96-week, open-label, prospective, randomized, multicenter study, we compared once-daily ABC/3TC 600 mg/300 mg with FPV 1400 mg/r 100 mg or EFV 600 mg in ARV-naïve, HIV-1-infected subjects with entry viral load (VL) >5,000 c/mL, were HLA-B*5701 negative, and did not have major resistance mutations to study drugs. The primary endpoint was time to switch of third drug or time to development of any treatment-related Grade 3 or 4 adverse events (AEs). Results from the planned 48-week analysis are reported.

Summary of results

SUPPORT enrolled 32% (32/101) women and 79% (80/101) non-Caucasians. Baseline and demographic characteristics were generally similar between groups. A total of 84 subjects (83%) completed study through W48. Eight patients met the primary endpoint: 3 (6%) and 5 (10%) on FPV/r and EFV, respectively. At W48, by ITT-Exposed missing-equals-failure analysis, 76% (39/51) and 82% (41/50) of subjects achieved VL <50 c/mL on FPV/r vs. EFV, respectively. Median change from baseline to W48 in CD4 cell count was 178 cells/mm3 in each group. Rate of treatment-related grade 2-4 AEs was lower in the FPV/r-arm (9/51, 18%) vs. the EFV-arm (15/50, 30%) primarily due to EFV-related rash and dizziness (8% each). Rates of treatment-related serious AEs and grade 3-4 lab abnormalities were similar between FPV/r vs. EFV. A total of 8 virologic failures occurred through W48. At failure, HIV PRO or RT treatment-emergent mutations were present in 4 of 5 EFV patients and 1 of 3 FPV/r patients selected an RT mutation. Median change from BL in total/HDL cholesterol ratio was unchanged in both groups but the FPV/r arm had larger changes in triglycerides (32 vs. 7 mg/dL) and in LDL cholesterol (22 vs. 11 mg/dL).


Through 48 weeks, in a diverse population, virologic/immunologic responses were not demonstrably different between FPV/r and EFV when given with ABC/3TC, but the EFV regimen had slightly more patients meeting the tolerability endpoint, treatment-related grade 2-4 AEs, virologic failures, and treatment-emergent mutations at failure.

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This article is published under license to BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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Kumar, P., DeJesus, E., Huhn, G. et al. SUPPORT: 48-week results of fosamprenavir/ritonavir vs efavirenz with abacavir/lamivudine in under-represented, antiretroviral-naïve patients. JIAS 13 (Suppl 4), P7 (2010).

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  • Cholesterol
  • Viral Load
  • Primary Endpoint
  • Efavirenz
  • Resistance Mutation