Abstract

In a 24-week phase 4, non-randomized, open-label, single-arm study, 19 HIV-infected patients receiving amprenavir (APV)-based highly active antiretroviral therapy (HAART) for 1.3-4.2 years (mean, 3.1 years) were switched to equimolar fosamprenavir (FPV) doses with no other changes in their treatment regimens. Most patients (74%) received APV/ ritonavir 600mg/100mg twice daily at screening. All but one were switched to FPV/ritonavir 700mg/100mg twice daily. Between baseline and week 24 after switching, clinical status generally remained stable or improved: median viral load 751 vs 71 copies/mL; CD4+ count 570 vs 622/mm3; proportion with viral load <400 copies/mL 47% vs 71%, and <50 copies/mL, 32% vs 35%. In 13 patients whose baseline HIV-1 RNA was >50 copies/mL, eight remained at this level and three were below it at week 24 (the other two were lost to follow-up). No study drug-related adverse events were reported and laboratory values did not notably change.