3rd Conf Retro and Opportun Infect. 1996 Jan 28-Feb 1;:162. Unique
Genotypic and phenotypic resistance were analysed in the virology subset
of 173 Delta 1 AZT-naive patients at baseline, 24, 48, 80 and 112 weeks
after commencing therapy (AZT alone, AZT plus ddI or AZT plus ddC).
Using the point mutation assay (PMA) genotypic changes were investigated
at codons 41, 67, 70, 215, 219 (AZT), 65, 69,74,75 and 184 (ddC/ddI).
Proportion values above, 4% for T215F/Y and 2% for all other mutant
codons were regarded as resistant. Pre-treatment analysis demonstrated
that 10 of 173 patients (pt) had detectable genotypic resistance
(T215F/Y = 2pt; K70R = 7pt; T215F/Y + K70R = lpt) to date 3 out of 10
have been found not to exhibit phenotypic resistance. No mutations were
identified at any other points prior to therapy. The proportion of
patients with AZT resistance at codon 70 was significantly greater in
the, AZT-alone group than in the combination therapy groups(logrank p
less than 0.0001). No significant differencs in the proportion of the
other resistant mutations associated with AZT were found between the
treatment groups. In patients receiving combination therapies no
mutations associated with ddI or ddC were detected out to 112 weeks.
Further analysis of data including quantitative measures of genotypic
resistance and phenotypic resistance will be presented.
Antiviral Agents/ADMINISTRATION & DOSAGE/*THERAPEUTIC USE Clinical
Trials Codon Didanosine/ADMINISTRATION & DOSAGE/THERAPEUTIC USE Drug
Resistance, Microbial/*GENETICS Drug Therapy, Combination *Genotype
HIV Infections/DRUG THERAPY/*VIROLOGY HIV-1/*GENETICS Human
*Phenotype Point Mutation Zalcitabine/ADMINISTRATION &
DOSAGE/THERAPEUTIC USE Zidovudine/ADMINISTRATION & DOSAGE/THERAPEUTIC