9TH EUROPEAN AIDS CONFERENCE (EACS)
1st EACS RESISTANCE & PHARMACOLOGY WORKSHOP

October 25 - 29, 2003 Warsaw, Poland

4.1 PK and Pharmacodynamics

F2/4 - INDINAVIR PLASMA EXPOSURE IS NOT AFFECTED BY RITONAVIR/LOPINAVIR CO-ADMINISTRATION IN A BOOSTED DOUBLE PI-ONLY THERPAY REGIMEN
* Von Hentig N.1, Dauer B.2, Moesch M.2, Carlebach A.2, Lutz T.3, Kurowski M.4, Harder S.1, Staszewski S.2
 
(1) Pharmazentrum Frankfurt, J.W.Goethe-University Hospital, Frankfurt, Germany,2 Medical HIV Treatment and Research Unit, J.W.Goethe-University Hospital, Frankfurt, Germany,3 Internal Medical Practice Grueneburgweg, Frankfurt, Germany,4 THERAPIA GmbH, AVK-Hospital, Berlin, Germany
 

Background: For HIV-patients who have lost their treatment options with reverse transcriptase inhibitors (RTI), a protease-inhibitor (PI) only regimen could be a treatment alternative. The co-administration of Saquinavir and Lopinavir/Ritonavir (LPV/r) has already been shown as a possible salvage therapy regimen.

Objectives: We investigated the potential pharmacokinetic interaction of a boosted double PI regimen of Lopinavir/Ritonavir (LPV/r) plus Indinavir (IDV).

Methods: We determined 12-h plasma drug levels of IDV, LPV and RTV in HIV-1 infected adult patients, taking IDV 800mg plus LPV/r 399/99mg BID only and compared the results to patients with LPV/r 399/99mg BID (plus 2 or 3 nucleoside RTI). The results were evaluated by a non-compartmental 2-stage approach and in addition a pre-defined 2-compartmental model (TOPFIT 2.0®).

Results: The addition of LPV to a IDV/RTV therapy regimen does not affect the IDV Area under the curve under steady state conditions (AUCss) despite significantly lower RTV plasma levels. The non-compartmental results are presented in the table.

Treament (group)  n  AUCss (ng12h/ml)  Cmax (ng/ml)  Cmin (ng/ml) 
    median (range)  median (range)  median (range) 
IDV (A)  15  37290(19384-49975)  5290(3120-6900)  824(295-1780) 
LPV (A)  15  72420(47715-117200)  7170(4740-11200)  4650(1440-6320) 
RTV (A)  15  4203(1750-6506)*  583(344-679)*  135(36-283)* 
IDV (B) ²  14  42381(18254-63320)  5610(3150-9360)  690(247-3390) 
RTV (B) ²  14  12569(3922-26771)  1365(493-4280)  376(124-871) 
LPV (C) ²  13  69440(37240-158000)  7740(4250-16300)  3790(946-9460) 
RTV (C) ²  13  2794(853-4520)**  424(94-830)**  77(44-224)*** 
² co-administration of 2 or 3 NRTI
* p<0,005;
** p< 0,0001 (Mann-Whitney U-test: compared to RTV in the IDV/RTV group (B) All statistics were performed by BIAS 7.06 ®

Conclusion: The comparison of the RTV plasma exposure in all groups is indicating, that even low RTV plasma levels sufficiently booster IDV or LPV. A dose adjustment of IDV, co-administrated with LPV/r in a double-PI regimen is not necessary.

Presenting Author: Nils Von Hentig, J.W.Goethe-University, Pharmazentrum, Theodor-Stern-Kai 7, 60590, Frankfurt/M., Germany, Phone: 0049-69-63017622

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