Pilot Study Evaluating Interruption of Enfuvirtide (Fuzeon, T20) in Patients With Enfuvirtide Resistance

Inclusion Criteria: * Currently receiving continuous enfuvirtide-based antiretroviral therapy. * Documentation of recent plasma HIV RNA level greater than the lower limit of detection (measured within the preceding 4 weeks) * Screening plasma HIV-1 RNA level \> 1000 copies/mL. * Negative serum pregnancy test (for women of childbearing potential) documented within the 14-day period prior to study entry. * Subjects must be able to give written informed consent and agree to abide by the requirements of the study. Exclusion Criteria: * Unstable HIV disease status such that interrupting any antiretroviral therapy poses significant short-term risk for disease progression (as determined by study investigators and referring primary care provider). * Female subjects who are pregnant, breastfeeding, or who plan to become pregnant during the study. * Active hepatitis C infection requiring treatment with an interferon-based regimen. * Evidence of active, untreated opportunistic infections or unexplained temperature which is \> 38.5°C for seven consecutive days, within 30 days prior to the first screening visit.