The Switch Study: The Role of Lamivudine/Emtricitabine (3TC/FTC) in Antiretroviral Regimens

Inclusion Criteria:

• HIV-1 seropositive patients >= 18 years of age
• Willingness and ability to understand and sign a written informed consent and comply with the protocol procedure
• Prior treatment with nucleoside reverse transcriptase inhibitors (NRTI's), non-nucleoside reverse transcriptase inhibitors (NNRTI's) and protease inhibitor (PI)-containing regimens
• On a stable PI and 3TC or FTC -containing regimen for >= 2 months
• Plasma HIV-1 RNA >5000 copies/ml
• CD4 >100
• Documented M184V or I on genotype within 3 months of study entry
• At least 3 PI-associated resistance mutations on genotype within 3 months of study entry, (including known resistance mutations at codons 10, 30, 46, 50, 54, 71, 82, 84, and 90)

Exclusion Criteria:

• In the opinion of the investigator a patient that is either unwilling or unable to be adherent to antiretroviral drugs
• Requirement for concomitant treatment with medicines that interfere with the therapy prescribed in the study
• Patients who have never taken 3TC or FTC, or with no prior documentation of the M184V mutation
• Active hepatitis B infection
• Vaccination within 2 weeks of entering the study
• An acute opportunistic illness within 4 weeks of entering the study; chronic infections will not be excluded
• Use of immunomodulatory medications such as IL-2
• Planned use of enfuvirtide, (T20) in salvage regimen, (in T20 naïve subjects)