AEGiS-15IAC: Antiviral activity of the next generation NNRTI TMC125 against a panel of site-directed mutants encompassing mutations observed in vitro and in vivo.

15th International AIDS Conference

Bangkok, Thailand - July 11-16, 2004

Antiviral activity of the next generation NNRTI TMC125 against a panel of site-directed mutants encompassing mutations observed in vitro and in vivo.

Int Conf AIDS 2004 Jul 11-16; 15:(abstract no. WeOrA1271)

de Bethune MP, Vingerhoets J, De Baere I, Azijn H, Van den Bulcke T, Mc Kenna P, Pattery T, Pauwels R
Tibotec, Mechelen, Belgium

BACKGROUND: TMC125 is a potent next-generation NNRTI, active against wild type and NNRTI-resistant HIV-1, and with an increased genetic barrier to development of resistance. Multiple mutations are selected in vitro in the presence of TMC125 (e.g. at positions 100, 179, 181 and 194). Profiling of TMC125 against >5600 clinical isolates demonstrated that some infrequent mutations (K101P, Y181I) were associated with decreased phenotypic susceptibility. To study the effect of these mutations on TMC125 activity, >80 site-directed mutant (SDM) viruses with single, double or triple mutations were constructed. The prevalence (P) of each mutation was determined in a database of >7000 NNRTI resistant clinical isolates.

METHODS: Mutant PR-RT sequences were constructed in a pGEM-HXB2 DNA vector. SDM viruses were generated by recombination of the mutant PR-RT amplicon within HXB2. Phenotype and genotype were determined by the Antivirogram and VirtualPhenotype assays, respectively.

RESULTS: Among 60 single mutant strains including all known NNRTI resistance mutations, only 3 demonstrated a fold change (FC) in EC50 of >10, compared to wild-type: Y181I (12.5 FC, P=1.4%), Y181V (15.1 FC, P=1.0%) and F227C (10.1 FC, P=0.01%). Of 19 double mutants, 1 strain showed a FC >10: V179F + Y181C (129 FC, P=0.5%). Other, more prevalent, combinations of 2 NNRTI mutations, including L100I, K103N, Y181C and G190A, showed a FC<10 for TMC125, whereas 11/19 showed a FC>10 for efavirenz. 4/9 triple mutants showed a FC >10 for TMC125. These strains contained L100I + K103N with either Y181C or T386A and K103N + Y181C with either V179I or Y318F. The prevalence of these triple mutants was<2%.

CONCLUSIONS: The antiviral activity of TMC125 is not affected by the majority of the mutations, single or multiple, observed after in vitro selection or associated with decreased susceptibility of clinical isolates. Only less prevalent mutations are associated with a decreased susceptibility to the compound. Long-term antiviral activity in patients with NNRTI-resistant HIV-1 is currently being evaluated.

Keywords: AEGIS, Antiviral Agents, Reverse Transcriptase Inhibitors, HIV-1, HIV-1 Reverse Transcriptase, Anti-HIV Agents, Oxazines, Mutation, Genotype, Single Person, efavirenz, In Vitro, Humans, genetics

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