Pharmacokinetic and Safety Study of Raltegravir and Atazanavir in a Once Daily Dose Regimen in HIV-1 Infected Patients

Inclusion Criteria: * HIV-infected as documented by positive HIV antibody test and confirmed by Western Blot. * Subject is at least 18 years of age at the day of screening. * Subject is able and willing to sign the Informed Consent Form prior to screening evaluations. * HIV-1 RNA \< 40 copies/mL for at least 6 months on antiretroviral therapy. * Subject has no history of previous virological failure or documented resistance mutations Exclusion Criteria: * History of sensitivity/idiosyncrasy to the drug or chemically related compounds or excipients, which may be employed in the trial. * Relevant history or current condition that might interfere with drug absorption, distribution, metabolism or excretion. * Inability to understand the nature and extent of the trial and the procedures required. * Pregnant female (as confirmed by an HCG test performed less than 3 weeks before the first dose) or breast-feeding female. * Abnormal serum transaminases determined as levels being \> 5 times upper limit of normal (see Appendix A for normal ranges of clinical laboratory values). * Concomitant use of medications that interfere with raltegravir or atazanavir pharmacokinetics: rifampicin, irinotecan, midazolam, triazolam, ergotamine, dihydroergotamine, cisapride, pimozide, lovastatin, simvastatin, indinavir, proton pump inhibitors, H2 receptor antagonists, St. john's wort, Ginkgo Biloba, didanosine, tenofovir, efavirenz, nevirapine, antacids, clarithromycin, phenytoin, phenobarbital, carbamazepine. * Active hepatobiliary or hepatic disease (including chronic hepatitis B infection). * Alcohol abuse.