1st EACS RESISTANCE & PHARMACOLOGY WORKSHOP
October 25 - 29, 2003 Warsaw, Poland
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9TH EUROPEAN AIDS CONFERENCE (EACS) 1st EACS RESISTANCE & PHARMACOLOGY WORKSHOP October 25 - 29, 2003 Warsaw, Poland |
| 3.4 Resistance Testing in Clinical Practice F6/5 - VIROLOGIC OUTCOME OF PATIENTS WITH VIROLOGIC FAILURE WHO START A REGIMEN CONTAINING ABACAVIR: EUROSIDA STUDY |
| (1) IrsiCaixa Foundation & Lluita contra la SIDA Foundation, Badalona, Spain,2 Royal Free Centre for HIV Medicine, London, UK,3 International Clinical Virology Center (ICVC), Buckinghamshire, UK,4 EuroSIDA Coordinating Center, Hvidovre Hop. Denmark,5 GlaxoSmithKline, Greenford, UK,6 University Hospital, Zurich, Switzerland |
Background: There are various measures of abacavir (ABC) resistance obtainable from genotypes and these require evaluation.
Objectives: To assess the association between baseline resistance and viral load outcome in ART-experienced, ABC-naïve people starting an ABC-containing regimen in EuroSIDA.
Patients and Methods: Patients VL>1,000 copies/mL and plasma sample at baseline were included. Genotyping was determined using TrueGene HIV-1 assay. Resistance to ABC was measured by number of abacavir-related mutations (using IAS-USA guidelines), VGI, Rega 4.0 rules and number of TAMs.
Results: Baseline median VL was 4.41 log10 copies/mL for the 115 patients included. For 31 patients ABC was the only drug added, 1 started ABC with two recycled drugs, and 83 with 1 ³ new antiretroviral. The median (range) number of ABC mutations was 3 (0-8) - around half had ABC resistance according to VGI/Rega scores. Overall median VL week 24 decline was 2.76 log10 copies/mL (95%CI:2.38-3.07). The VGI, number of TAMs and number of abacavir-related mutations, but not the Rega system were significantly univariably associated with outcome. After adjustment for baseline VL, number of active drugs started (other than ABC, according to Rega system) and number of drugs previously received there was a 0.09 cps/ml less VL reduction per additional IAS mutation (p=0.09) and a 0.10 cps/ml less reduction per additional TAM (p=0.08). Rega and VGI showed little association.
Conclusions: The ABC measures were not clearly associated with response, suggesting that these algorithms may need further improvements. The predictive value of other ABC resistance measures will be presented.
Presenting Author: PhD Lidia Ruiz, IrsiCaixa Foundation & Lluita contra la SIDA Foundation, Badalona, Spain, Carretera de Canyet s/n, 08916, Badalona, Spain, Phone: 34 93 465 63 74
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