3rd International Workshop on Adverse Drug Reactions and Lipodystrophy in HIV 23-26 October 2001, Athens, Greece

EFFECT OF LOW-DOSE RITONAVIR ON METABOLIC PARAMETERS IN THERAPY-NAÏVE SUBJECTS STARTED ON AMPRENAVIR/LAMIVUDINE/ABACAVIR (GSK COL30325)

Antiviral Therapy 2001; 6(Suppl. 4):31 (abstract no. 41)

A Burnside¹, L Bush², E DeJesus³, C Farthing⁴, G Boone⁵, A Hirani⁵ and J Hernandez^5
1 Burnside Clinic, Columbia, SC, USA; ² National Research Associates, Palm Beach, Fla., USA; ³ IDC Research Initiative, Altamonte SPG, Fla.,USA; ⁴ AIDS Healthcare Foundation, Los Angeles, Calif., USA; and ⁵ GiaxoSmithKline, Research Triangle Park, NC, USA

OBJECTIVES: To evaluate changes in metabolic parameters in a ritonavir-boosted ampranivir-containing highy active antiretroviral therapy regimen in therapy-naïve subjects.

METHODS: A 48-week open-label-pilot study was initiated to evaluate amprenavir 1200 mg/lamivudine 150 mglabacavir 300 mg twice daily in 38 therapy-naïve adults. This protocol was amended to include low-dose ritonavir mid-stream; however, the addition of ritonavir as a pharmacokinetic booster may have negative effects on metabolic parameters. Subjects switched to ampenavir 600 mg/ritonavir 100 mg twice daily at varying times. The median time to switch was 12 weeks, range (2-43) and the median time on boosted therapy was 36 weeks. Baseline metabolic values were obtained at entry and just before ritonavir was added.

RESULTS: Information was available for 26 subjects. Median baseline values at enty for total cholesterol, triglycerides, and glucose were 155, 115 and 92 mg/dl, respectively. Median values just before the addition of ritonavir for total cholesterol, high-density lipodystrophy (HDL) cholesterol, triglycerides and glucose were 191,43, 145 and 92 mg/dl, respectively. Changes in cholesterol and triglycerides pre-switch were statistically significant. After the addition of ritonavir, there were statistically significant increases in total cholesterol at weeks 8, 16 and 24 (9, 27 and 36 mg/dl, respectively) and a one-time increase in triglycerides at week 4 (P=0.048) compared to the pre-switch baseline. There were no changes in glucose or HDL cholesterol levels. Overall, only four subjects had grade 3 cholesterol and three subjects had grade 3 or 4 triglyceride elevations. In all subjects, the addition of ritonavir either maintained or increased viral suppression and there was no increase in adverse experiences after the addition of ritonavir.

CONCLUSIONS: In this pilot study, only moderate additional total cholesterol elevations were noted following ritonavir-boosting of amprenavir. Minimal changes in triglycerides and no changes in HDL cholesterol or glucose were observed.

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