In subjects with moderate hepatic impairment (Child-Pugh score of 7-9), a reduced dose of fosamprenavir 450 mg twice daily with a reduced dosing frequency of ritonavir 100 mg once daily is 20 predicted to deliver similar plasma amprenavir Cmax and AUC(0-12), but approximately 35% lower plasma total amprenavir C12 values and approximately 88% higher plasma unbound amprenavir C12 values than achieved in subjects with normal hepatic function receiving the standard fosamprenavir with ritonavir 700 mg / 100 mg twice daily regimen.