JAC Advance Access originally published online on September 22, 2009
Journal of Antimicrobial Chemotherapy 2009 64(6):1260-1264; doi:10.1093/jac/dkp348
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Original research |
Once-daily treatment with saquinavir mesylate (2000 mg) and ritonavir (100 mg) together with a fixed-dose combination of abacavir/lamivudine (600/300 mg) or tenofovir/emtricitabine (245/200 mg) in HIV-1-infected patients
1 HIVCENTER, JW Goethe University Hospital, Theodor Stern Kai 7, 60590 Frankfurt, Germany 2 Infektiologikum, Stresemannallee 3, 60596 Frankfurt, Germany 3 Therapia GmbH, c/o Vivantes Auguste-Viktoria Klinikum, Rubensstraße 125, 12157 Berlin, Germany 4 Infektiologikum, Friedensstraße 2, 60311 Frankfurt, Germany
Received 5 May 2009; returned 11 June 2009; revised 31 August 2009; accepted 1 September 2009
* Corresponding author. Tel: +49-69-6301-7478; Fax: +49-69-6301-84325; E-mail: markusbickel{at}hotmail.com
Objectives: To investigate the feasibility and pharmacokinetics of a once-daily regimen of 2000 mg saquinavir mesylate boosted with 100 mg ritonavir.
Patients and methods: Patients successfully treated with 1000 mg saquinavir boosted with 100 mg ritonavir twice daily together with two nucleoside or nucleotide reverse transcriptase inhibitors [N(t)RTIs] who were switched to 2000 mg saquinavir with 100 mg ritonavir once daily with unchanged N(t)RTI therapy were analysed. CD4 cells, HIV-RNA PCR and metabolic parameters were compared between baseline and 3, 6, 9 and 12 months after the switch. Saquinavir and ritonavir drug levels were measured before and a median of 3 weeks after switching from twice to once daily at 0, 1, 2, 4, 6, 9, 12 and 24 h after intake of the medication. The area under the serum concentration–time curve from 0 to 24 h (AUC0–24) was calculated using the trapezoidal rule.
Results: Eighteen patients (16 males, median age of 41 years) with a median CD4 cell count of 464 cells/mm3 were analysed. HIV-RNA PCR remained <500 copies/mL for all patients. After switching from 100 mg twice daily to 100 mg once daily, the AUC0–24 for ritonavir decreased significantly [21 874 to 10 267 ng·h/mL, geometric mean ratio (GMR) = 0.47; P < 0.001], whereas the AUC0–24 for saquinavir decreased only marginally from 35 000 to 34 490 ng·h/mL (GMR = 0.99; P = 0.426). The CD4 cell count and the fasting metabolic parameters remained unchanged.
Conclusions: Once-daily treatment with ritonavir-boosted saquinavir was well tolerated and resulted in similar saquinavir drug exposure despite much lower ritonavir concentrations when compared with a twice-daily dosing schedule.
Keywords: pharmacokinetics , protease inhibitors , therapeutic drug monitoring