A Phase II Open-label, Randomized, Active-controlled Study Comparing the Efficacy and Safety of Once Daily Enfuvirtide Dosing Versus the Currently Recommended Twice Daily Dosing in HIV-1 Infected Treatment-experienced Patients.

This study will assess the safety and efficacy of once-daily administration of Fuzeon compared with twice-daily administration in HIV-1 infected patients who have received prior treatment. Patients will also receive an optimized treatment consisting of antiretroviral (ARV) therapy as determined by the treating physician. The anticipated time on study treatment is 3-12 months, and the target sample size is 100-500 individuals.