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Abstract
Tipranavir/ritonavir (TPV/r) 500 mg/200 mg BID drives week 24 viral load (VL) below 400 copies/mL when combined with a second active drug (T-20) in protease inhibitor experienced HIV+ patients.
Valdez H.1, McCallister S.1, Kohlbrenner V.1, Mayers D.1
1Boehringer Ingelheim Pharmaceuticals, Inc., Ridgefield, United States of America
Background: TPV is a new non-peptidic protease inhibitor (PI) with activity against multidrug resistant HIV-1. The combination of TPV with a high Inhibitory Quotient (IQ) against PI-resistant viruses and T-20 as a second active drug could be very potent in patients with limited treatment options.
Methods: Phenotypic testing was performed on 450 randomly selected baseline samples from participants in the RESIST trials. Trough TPV concentrations were determined at weeks 2 and 4. Using TPV drug susceptibility and geometric mean TPV plasma concentrations the TPV IQ was calculated. Week 24 virologic responses were analyzed according to TPV IQ and T-20 use.
Results: RESIST patients had previously received a median of 12 antiretrovirals including 4 PIs. Median baseline CD4 and VL were 155 cells/mm3 and 4.8 log10 copies/mL. 58% of patients who used TPV + T-20 achieved a ³1 log10 VL reduction at week 24. 70% of patients who were naive to T-20 and received TPV/r achieved a 1 log10 VL reduction at week 24, while only 31% of patients who received TPV and T-20—but were T-20 experienced—had a ³1 log10 VL reduction. 99 patients on TPV and T-20 had IQ determinations: 42% (42/99) had a TPV IQ <60 and 57.6% (57/99) an IQ ³60. Week 24 VL responses for patients who used T-20 and had a TPV IQ ³60 were ³1 log10 in 80.7% (46/57) of patients; VL <400copies/mL in 59.6%% (34/57) and VL <50 copies/mL in 36.8% (21/57).
Conclusions: Most PI-experienced patients who received a TPV/r -containing regimen achieved an IQ ³60. With this IQ, 81% of patients who also included a new class of drug in the regimen achieved a week 24 viral load reduction of 1 log10 or more. Nearly 60% of these hard-to-treat patients achieved a week 24 VL <400 copies/mL.
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