Atazanavir for treatment of HIV infection in clinical routine: efficacy, pharmacokinetics and safety.

ABSTRACT

INTRODUCTION: Atazanavir (ATV) is a novel protease inhibitor that has been recently introduced into therapy of HIV infection. Currently there is little data on ATV therapy from daily practice. METHODS: In this retrospective study, we report on ATV efficacy and safety in clinical routine. Drug monitoring was performed consisting of unscheduled single measurements and a 4-hour-profile. Trough concentration of >80 ng/ml and peak concentration of 2000-6000 ng/ml were regarded as sufficient. RESULTS: Between May 2003 and April 2004, ATV treatment was started in 42 patients, mean observation time was 32 weeks (6-53). Mean age was 45.6 years, 38% had prior AIDS, viral load was undetectable in 73%. Important side effects were minor or moderate diarrhea (27%) and fatigue (15%). ATV was discontinued in 10% due to side effects or malignant diseases. No significant influence on mean values of cholesterol, triglycerides, liver enzymes, CD4-cell-count, and HI-viral load was seen. Virologic failure occurred in 13% of patients, all of them were PI-experienced. Pharmacokinetic data are available for 32 patients, all patients had sufficient trough levels. 30% with unboosted ATV and 21% with boosted ATV had peak plasma concentrations below the level defined as sufficient. Mean trough levels, plasma profile and AUC did not differ significantly between groups with non-boosted versus boosted ATV regimes but showed a wide inter-patient variability. CONCLUSIONS: ATV treatment of HIV-infected patients with or without a RTV booster was safe and effective in clinical routine. Drug levels were sufficient in the majority of cases. The variability of pharmacokinetic results in our sample supports therapeutic drug monitoring in patients treated with ATV.