A low dose of ritonavir-boosted atazanavir provides adequate pharmacokinetic parameters in HIV-1-infected Thai adults.

Contains fulltext : 81235.pdf (publisher's version ) (Closed access)Several dose-finding studies of boosted protease inhibitors have demonstrated that doses lower than those recommended in Caucasian populations exhibit in the Thai population similar pharmacokinetic (PK) properties with sustained virological suppression but reduced toxicity. We therefore evaluated the PK profiles of lower than the standard doses of atazanavir/ritonavir (ATV/RTV) in 22 adult Thai patients with well-suppressed human immunodeficiency virus 1 (HIV-1) infection. The PK parameters of ATV/RTV at a dosage of 200/100 mg once daily, plus two nucleoside reverse transcriptase inhibitors, were significantly lower than those associated with a dosage of 300/100 mg once daily in the same patients. In addition, the PK parameters for the lower dosage in these Thai patients were comparable to historical data from Caucasian cohorts who received the standard dose of ATV/RTV (300/100 mg). None of the patients showed subtherapeutic values of <0.15 mg/l at any time point. Bilirubin concentration decreased significantly after dose reduction, and viral load remained at <50 copies/ml in all subjects. Therefore, ATV/RTV at a dose of 200/100 mg once daily (plus appropriate backbone medication) warrants further long-term efficacy studies, particularly in patients of Thai and other Asian ethnicities

Two Different Patterns of Mutations are Involved in the Genotypic Resistance Score for Atazanavir Boosted Versus Unboosted by Ritonavir in Multiple Failing Patients

The protease inhibitor atazanavir (ATV) can be used either boosted by ritonavir (ATV300/r) or unboosted (ATV400). To date, however, genotypic resistance scores (GRSs) have been developed only for boosted-ATV. We have determined GRS associated with virologic response (VR) for both ATV300/r and ATV400 in highly pre-treated HIV-1 infected patients