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1st International Workshop on HIV Drug Resistance & Treatment Strategies25-28 June 1997, St. Petersburg, Florida, USA |
THE PROTEASE-RT ANTIVIROGRAM™: SIMULTANEOUS DETECTION OF PHENOTYPIC (MULTI-) DRUG RESISTANCE OF PLASMA HIV-1 FROM PATIENTS TREATED WITH VARIOUS REVERSE TRANSCRIPTASE AND/OR PROTEASE INHIBITORS
Antiviral Therapy 1997;2 (Suppl 5):28 (abstract no. 42)
K Hertogs2, M-P de Béthune1, V Miller3, S Staszewski3, T Ivens1, H Azijn1, P Schel2, A Van Cauwenberge2, C Van den Eynde2, V van Gerwen2, M Van Houtte2, F Peeters2 and R Pauwels1,2
1TIBOTEC and 2VIRCO, Antwerp, Belgium, 3W Goethe Universität, Frankfurt, Germany
OBJECTIVE: Protease (PR) inhibitors in combination anti-HIV-1 therapy have shown very promising results. The emergence of drug resistant mutants however strongly correlates with therapy failure. Our objective was to facilitate analysis of the emergence of resistance to reverse transcriptase (RT) and PR inhibitors and their respective roles in therapy failure. Analogous to the previously described RT Antivirogram™, a genetic construct lacking PR and RT coding sequences was developed that allows for the simultaneous determination of the phenotypic sensitivity (or resistance) of the circulating virus population from individual patients to all RT and PR inhibitors.
METHODS: The combined PR and RT coding sequence from patient plasma HIV was RT-PCR amplified and hybrid laboratory HIV strains containing these amplified genes and the deletion construct were generated. Drug susceptibility to RT and PR inhibitors was determined in a highly automated anti-HIV evaluation system. The PR-RT Antivirogram™ graphically represents the resistance profile of the patient virus population to the tested antiretroviral drugs.
RESULTS: Susceptibility determinations of the analysed patient population demonstrated that (1) various levels of drug-specific resistance to RT and PR inhibitors can emerge during therapy; (2) a good correlation exists with the therapy history of the patients; and (3) prolonged exposure of replicating virus, carrying PR and/or RT-resistance-associated mutations, led to increased levels of resistance to drugs included in the therapy or cross-resistance to other inhibitors. Dideoxy-based sequencing of the RT and PR genes from these patients revealed complex genotypic patterns.
CONCLUSION: Phenotypic resistance testing can play an important role in the virological evaluation of new drugs (RT and PR inhibitors) and combinations of these drugs, in clinical trials. More extensive studies using the PR-RT Antivirogram™ as a tool for individualized patient management will be performed. The designed in vitro system will facilitate the rapid simultaneous phenotypic resistance determination for all RT and PR inhibitors on a large-scale basis.
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1997-06-25
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