Durable efficacy of enfuvirtide over 48 weeks in heavily treatment-experienced HIV-1-infected patients in the T-20 Versus Optimized Background Regimen Only 1 and 2 clinical trials

Background: The T-20 Versus Optimized Background Regimen Only (TORO) I and TORO 2 clinical trials are open-label, controlled, parallel-group, phase 3 studies comparing enfuvirtide plus an optimized background (OB) of antiretroviral s (n = 661) with OB alone (n = 334) in treatment-experienced HIV-1-infected patients. Methods: The primary objective at week 48 was to investigate durability of efficacy, as measured by the percentage of patients maintaining their week 24 response or improving. Efficacy analyses used the intent-to-treat population. Results: A total of 73.7% of patients randomized to the enfuvirtide group remained on treatment through week 48 versus 21.3% originally randomized to the control group. At week 48, a higher proportion of week 24 responders maintained their response or were new responders in the enfuvirtide group than in the control group in each responder category: HIV-1 RNA level >= 1.0 log(10) change from baseline, <400 copies/nL and <50 copies/mL (37.4%, 30.4%, and 18.3% in the enfuvirtide group vs. 17.1%, 12.0%, and 7.8% in the control group, respectively; P < 0.0001 for all comparisons). CD4 cell count increases from baseline were twice as great in the enfuvirtide group as in the control group. Conclusion: These data demonstrate durable efficacy of enfuvirtide plus OB over 48 weeks. the patients enrolled in the 2 TORO studies presented with a range of treatment histories and demographic and baseline characteristics, reflecting the heterogeneity of the HIV-infected patient population. Therefore, we have carried out exploratory analyses to compare treatment effects between the enfuvirtide and control groups by different factors after 48 weeks.