GW873140 In Combination With Kaletra In HIV Infected Subjects

Inclusion criteria: * HIV infected, therapy-naive subjects. * Females must be of either non-childbearing age, or have a negative pregnancy test. * All subjects participating in this study should be counseled on the practice of safe sex using a proven double barrier method of contraception throughout the study. * Screening lab result of plasma HIV-1 RNA greater than or equal to 50,000 copies/mL and CD4 cell count greater than or equal to 100 cells/mm3. * Have CC Chemokine Receptor5-tropic (R5-tropic) or CC Chemokine Receptor5/CXC Chemokine Receptor4-tropic (R5/X4-tropic) virus based on viral tropism test at screening visit. * Be treatment-naive, defined as less than or equal to 2 weeks of treatment with a protease inhibitor (PI) or an nucleoside reverse transcriptase inhibitor/nucleotide reverse transcriptase inhibitor (NRTI/ NtRTI), or less than or equal to 7 days of therapy with a non-nucleoside reverse transcriptase inhibitor (NNRTI). * Prior treatment with any entry inhibitor, attachment inhibitor, or fusion inhibitor (experimental or approved) is not allowed. * Be able to understand and follow with protocol requirements, instructions and protocol-stated restrictions. * Signed and dated written informed consent prior to study entry. Exclusion criteria: * No detection of CXC Receptor4-tropic (X4-tropic) virus only, based on viral tropism test at screening. * No active Class C AIDS-defining illness. * No laboratory abnormalities at screen. * No significant blood loss prior to study start. * No pregnant or breastfeeding women. * Additional qualifying criteria to be determined by the physician.