The Maraviroc Central Nervous System (CNS) Study

Inclusion Criteria: * HIV-1 infected males or females * signed informed consent * plasma HIV RNA \< 50 copies/mL at screening and on at least one other occasion over the last 3 months * currently receiving a stable antiretroviral regimen comprising of: * tenofovir 245 mg daily * emtricitabine 200 mg daily * a boosted protease inhibitor * no previous protease inhibitor resistance documented on HIV-1 genotypic resistance testing * Between 18 to 65 years of age, inclusive * subjects in good health upon medical history, physical exam, and laboratory testing * Female subjects who are heterosexually active and of childbearing potential (i.e., not surgically sterile or at least two years post menopausal) must practice contraception as follows from screening through completion of the study including 30 days following last dose of study drug: * barrier contraceptives (condom, diaphragm with spermicide) * IUD PLUS a barrier contraceptive * Female subjects of childbearing potential must have a negative pregnancy test. * Male subjects who are heterosexually active must use two forms of barrier contraception (e.g., condom with spermicide) during heterosexual intercourse, from screening through completion of the study including 30 days following last dose of study drug. * Have no serologic evidence of active HBV infection evidenced by negative hepatitis B surface antigen and no serologic evidence of hepatitis C virus infection by a HCV antibody or HCV PCR. * Have screening laboratory results (haematology, chemistry, and urinalysis) that fall within the normal range of the central laboratory's reference ranges unless the results have been determined by the Investigator to have no clinical significance Exclusion Criteria: * current alcohol abuse or drug dependence * active opportunistic infection or significant co-morbidities including dementia * current prohibited concomitant medication (as listed in section 4.1.4) * Have a body mass index (BMI) \> 32 * Contraindication to lumbar puncture examination. Such as: * Existing neurological diseases * Bleeding disorders