Will once-daily fosamprenavir work with 100 mg of ritonavir?
Fosamprenavir/ritonavir ranks as one of several once-daily boosted protease inhibitor (PI) options sanctioned for treatment-naive people, at a dose of 1400/200 mg. But will 1400/100 mg once daily work just as well–and with fewer side effects? Three trials presented in Glasgow addressed that question, and all yielded generally favorable findings. But questions remain about how the 1400/100-mg dose will affect lipids over the long term. Earlier research charted 38% lower amprenavir troughs in HIV-negative volunteers taking fosamprenavir with 100 mg of ritonavir once daily than in those taking 200 mg of ritonavir [1]. (The body metabolizes fosamprenavir to amprenavir.) But those troughs remained 6 times higher than the protein binding-adjusted 50% inhibitory concentration for nonmutant (“wild-type”) virus. To see how the 100-mg boost compared with the 200-mg kicker, Duke University’s Charles Hicks and colleagues at other US sites randomized 115 previously untreated people to 100 or 200 m
