Administration of fosamprenavir 700 mg twice daily with ritonavir 100 mg twice daily results in plasma amprenavir concentrations (data from study APV30003 in antiretroviral experienced patients) which results in protein adjusted median ratios of Cmin/ IC50 and Cmin/ IC95 of 21.7 (range 1.19-240) and 3.21 (range 0.26-30.0), respectively.