This 2 arm study will evaluate the efficacy and safety of Fuzeon with an integrase inhibitor in an expanded access program plus optimized background in HIV-1 infected patients naive to Fuzeon and an integrase inhibitor. In the first cohort phase of the study, eligible patients will receive Fuzeon 90mg sc b.i.d. until confirmation of response (min/max = 8/16 weeks). In the second, randomised comparator phase of the study, responders will be randomized to receive Fuzeon either 90mg sc b.i.d. or 180mg qd for a further 24 weeks. Non-responders and virological failures will be terminated from the study. The anticipated time on study treatment is 3-12 months, and the target sample size is 100-500 individuals.

• Drug: enfuvirtide [Fuzeon]
• Drug: Optimized ARV background
• Drug: Integrase inhibitor

Inclusion Criteria:

• adult patients, >=18 years of age;
• HIV-1 infection;
• triple class treatment-experienced, Fuzeon- and integrase-inhibitor naive;
• GSS>=3; nucleosides excluded.

Exclusion Criteria:

• adverse clinical or laboratory experience >ACTG Grade 4;
• untreated infection, intercurrent illness, drug toxicity or other condition contraindicating an antiretroviral regimen;
• malignancy requiring chemotherapy or radiotherapy.