A randomized study investigating the efficacy and safety of amprenavir in combination with low-dose ritonavir in protease inhibitor-experienced HIV-infected adults.

Objectives: To compare the safety and efficacy of amprenavir [APV/j Agenerase trade mark; GlaxoSmithKline, [Ware, UK; 600 mg twice a day (bid)] boosted with low-dose ritonavir (RTV, 100 mg bid) with those of other protease inhibitors (PIs) in PI-experienced HIV-infected patients.

Study Design: Parallel-group, randomized, open-label, multicentre study.

Methods: One hundred and sixty-three patients with HIV predicted to be sensitive to APV, another PI and a nucleoside reverse transcriptase inhibitor (NRTI) were randomly assigned to receive either APV boosted with low-dose RTV (APV/r) or a standard of care (SOC) PI with or without low-dose RTV. The non-inferiority of APV/r to the SOC PIs was assessed by time-weighted average change from baseline (AAUCMB) in plasma viral load (vRNA) at week 16.

Results: The antiviral response for APV/r bid was non-inferior to that for the SOC PI group: the vRNA AAUCMB mean treatment difference was 0.043 log(10) HIV-1 RNA copies/mL [95% confidence interval (CI)-0.250, 0.335]. APV/r bid was generally well tolerated.

Conclusions: Results confirm the antiviral activity, short-term safety and tolerability of APV/r bid in PI-experienced patients.