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Switching to fosamprenavir (FPV) led to similar efficacy and safety in HIV-1-infected subjects on their first PI regimen: a prospective, open-label, multicenter, randomized trial (ESS100290)
B. Young1, E. Dejesus2, A. Lamarca3, P. Salvato4, D. Sutherland-Phillips5, L. Yau5, L. Patel5, P. Wannamaker5
1Denver Infectious Disease Consultants, Denver, United States, 2Orlando Immunology Center, Orlando, United States, 3Therafirst Medical Center, Fort Lauderdale, United States, 4Diversified Medical Practices, Houston, United States, 5GlaxoSmithKline, Research Triangle Park, United States
Background: FPV is an efficacious and well-tolerated PI; switching to FPV from another PI regimen may offer advantages in tolerability and virologic response.
Methods: Subjects on their first PI-regimen (HIV-1 RNA<400 c/mL for ³3 months) were randomized 1:1 to switch to FPV (± 200mgRTV) or continue their BL PI-regimen (stable NRTI background). Subjects in the BL PI-regimen arm were allowed to switch to FPV (± 200mgRTV) at Week 24. Primary efficacy endpoint was proportion of subjects with HIV-1 RNA<400 c/mL at 24 weeks (TLOVR, 12% non-inferiority margin).
Results: Baseline characteristics include median age 43 years in all arms; % males and African American subjects, respectively: FPV-switch (79%, 35%); BL-PI (78%, 34%); and Wk-24 FPV-switch (85%, 24%).
| PI Strata*, ITT(E) Population, n (%) | ATV | IDV | LPV/r | NFV | RTV | SQV | | FPV-switch, N=153 | 51 (33) | 9 (6) | 63 (41) | 26 (17) | 0 | 4 (3) | | BL-PI, N=97 | 36 (37) | 2(2) | 40 (41) | 17 (18) | 1 (1) | 1 (1) | | Wk-24 FPV-Switch, N=54 | 14 (26) | 6 (11) | 25 (46) | 7 (13) | 0 | 2 (4) | | *PI Strata determined by active PI (RTV boosting was at the discretion of the investigator). Full details of boosted regimens will be presented. |
| Efficacy and Safety | Week 24 | Week 48 | | TLOVR Responders, ITT(E) Population | BL FPV-switch (N=153) | Continue BL-PI (N=151) | BL FPV-switch (N=153) | Continue BL-PI (N=97) | Week 24 FPV-switch (N=54) | | HIV-1 RNA <400c/mL, n (%) | 137 (90)* | 140 (93)* | 116 (76) | 73 (75) | 49 (91) | | HIV-1 RNA <50c/mL, n (%) | 123 (80) | 129 (85) | 100 (65) | 67 (69) | 45 (83) | | Any drug-related Grade 2-4 AEs | 20% | 19% | 20% | | Any drug-related Grade 2-4 GI Event | 7% | 3% | 7% | | *FPV was non-inferior to BL PI at Week 24 (95% CI = -9.8, 3.5) |
Low rates of virologic failure (confirmed ³400 c/mL) were observed through Week 48 (FPV-switch, n=8, BL-PI, n=11; Wk-24 FPV-switch, n=0)
Conclusions: Virologic response was similar between FPV switch and BL PI arms at 24 and 48 weeks; subjects switched to FPV at Week 24 appeared to have higher virologic response rates. Adverse events were similar between groups; however subjects who switched regimens reported more GI AEs.
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