Study of once-daily versus twice-daily fosamprenavir plus ritonavir administered with abacavir/lamivudine once daily in antiretroviral-naïve HIV-1-infected adult subjects.
OBJECTIVE
Fosamprenavir/ritonavir 1400 mg/100 mg once-daily regimen may have a more favourable tolerability and lipid profile than the fosamprenavir/ritonavir twice-daily regimen, while maintaining comparable antiviral efficacy.


METHODS
This open-label study had a group-sequential design with a stage 1 Week 24 futility analysis, with both efficacy and safety go-criteria for progression to stage 2. There were 214 antiretroviral-naive, HIV-1-infected subjects who were randomised to receive either fosamprenavir/ritonavir 1400 mg/100 mg once daily or fosamprenavir/ ritonavir 700 mg/100 mg twice daily, both with abacavir/lamivudine fixed-dose combination tablet. Primary endpoints were the proportion of subjects achieving HIV-1 RNA <400 copies/mL at Week 48 and the mean change from baseline in fasting non-HDL cholesterol.


RESULTS
Though stage 1 futility analysis did not meet criteria for progression to stage 2, subjects enrolled in stage 1 were followed to Week 48 per protocol. At Week 48, noninferior efficacy of once daily to twice daily (95% CI around the treatment difference, -11.4 to 9.5) was achieved, with 86/106 (81%) subjects in the once-daily and 87/106 (82%) in the twice-daily arm achieving HIV-1 RNA <400 copies/mL. Mean change from baseline at Week 48 in non-HDL cholesterol was 1.10 mmol/L and 1.26 mmol/L (p = .478) for the once-daily and twice-daily arms, respectively.


CONCLUSIONS
Though the study did not continue to stage 2, fosamprenavir/ritonavir once daily demonstrated noninferior antiviral efficacy to fosamprenavir/ritonavir twice daily.
Univ Brescia, Brescia, Italy.
Carosi
Lazzarin
Stellbrink
Moyle
Rugina
Staszewski
Givens
Ross
Granier
Ait-Khaled
Leather
Nichols
D000293:Adolescent; D000328:Adult; D000368:Aged; D002219:Carbamates / Q000008:administration & dosage* / Q000009:adverse effects; D015224:Dideoxynucleosides; D004334:Drug Administration Schedule; D004338:Drug Combinations; D004359:Drug Therapy, Combination; D005260:Female; D005663:Furans; D015658:HIV Infections / Q000097:blood / Q000188:drug therapy*; D017320:HIV Protease Inhibitors / Q000008:administration & dosage* / Q000009:adverse effects; D015497:HIV-1 / Q000187:drug effects* / Q000235:genetics; D006801:Humans; D006949:Hyperlipidemias / Q000097:blood / Q000139:chemically induced; D019259:Lamivudine / Q000008:administration & dosage* / Q000009:adverse effects; D008074:Lipoproteins / Q000097:blood / Q000187:drug effects; D008297:Male; D008875:Middle Aged; D010755:Organophosphates / Q000008:administration & dosage* / Q000009:adverse effects; D012367:RNA, Viral / Q000097:blood / Q000187:drug effects; D018894:Reverse Transcriptase Inhibitors / Q000008:administration & dosage* / Q000009:adverse effects; D019438:Ritonavir / Q000008:administration & dosage* / Q000009:adverse effects; D013449:Sulfonamides / Q000008:administration & dosage* / Q000009:adverse effects; D013997:Time Factors; D016896:Treatment Outcome; D000099227:Abacavir
D002219:Carbamates; D015224:Dideoxynucleosides; D004338:Drug Combinations; D005663:Furans; D017320:HIV Protease Inhibitors; D019259:Lamivudine; D008074:Lipoproteins; D010755:Organophosphates; D012367:RNA, Viral; D018894:Reverse Transcriptase Inhibitors; D019438:Ritonavir; D013449:Sulfonamides; C492871:abacavir, lamivudine drug combination; D000099227:Abacavir; C426859:fosamprenavir