I studiet ESS100732 fik 16 ud af 434 ART- naive patienter, der blev behandlet med 700 mg fosamprenavir/ 100 mg ritonavir to gange daglig, virologisk svigt efter 48 ugers behandling.
Sixteen of 434 ART-naïve patients who received fosamprenavir 700mg/ ritonavir 100mg twice daily in ESS100732 experienced virological failure by Week 48 with 14 isolates genotyped.