Polymorphic Effects of Cytochrome P450 3A5 on Pharmacokinetics of Maraviroc and Its Metabolites

Inclusion Criteria: * Healthy with no acute medical illness * Willing to provide written informed consent * Age 18-65 years * Negative serum pregnancy test (females only) at screening and a negative urine pregnancy test (females only) on day of dosing * HIV seronegative at screening, as determined by any licensed ELISA * At screening, no evidence of hepatic or renal impairment (LFT's \< 1.5 Upper Limit of Normal (ULN), creatinine clearance \> than 60 ml/min, total bilirubin below ULN, AST and ALT below 1.5 ULN) * 8 subjects with homozygous CYP3A5 allele \*1 (wild type) * 8 subjects with 1 CYP3A5\*1 allele and 1 mutant allele * 8 subjects with CYP3A5 allele other than \*1 Exclusion Criteria: * Concomitant medication (prescription or over-the-counter) or herbal supplements for which there is a known risk of pharmacokinetic or pharmacodynamic drug interactions, including those that inhibit CYP3A4 as listed on the P450 Drug Interaction Table (http://medicine.iupui.edu/clinpharm/ddis/table.aspx) * History of postural hypotension or cardiovascular disease * Active medical or psychological condition that, in the opinion of the investigator, might put the volunteer at undue risk or interfere with the participation of the study