Open AccessGenotypic Correlates of a Virologic Response to Stavudine After Zidovudine Monotherapy
Author(s) -
Nancy S. Shulman,
Roderick A. Machekano,
Robert W. Shafer,
Mark A. Winters,
Andrew Zolopa,
Song Heng Liou,
Michael D. Hughes,
David Katzenstein
Publication year - 2001
Publication title -
journal of acquired immune deficiency syndromes
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.162
H-Index - 157
eISSN - 1944-7884
pISSN - 1525-4135
DOI - 10.1097/00126334-200108010-00008
Subject(s) - zidovudine , stavudine , genotype , medicine , virology , sida , reverse transcriptase , drug resistance , lentivirus , reverse transcriptase inhibitor , clinical trial , resistance mutation , biology , viral load , immunology , virus , viral disease , polymerase chain reaction , genetics , gene
Prior evidence suggests that resistance to zidovudine (ZDV) confers some degree of cross-resistance to stavudine (d4T), but no genotypic correlates of clinical d4T susceptibility and resistance exist. To identify the genotypic correlates of a virologic response to d4T, reverse transcriptase (RT) sequencing of archived plasma HIV isolates was performed on 31 subjects who received d4T monotherapy in the AIDS Clinical Trials Group 302 study, all of whom received more than 3 years of ZDV monotherapy. Baseline characteristics and all RT mutations were analyzed for impact on virologic suppression. Eight of 31 subjects (27%) achieved a virologic response of greater than 0.3 log reduction in plasma HIV RNA after 8 weeks of d4T. Responders were more likely to have lower median baseline viral loads (4.2 vs. 4.7; p =.01) and a trend toward fewer ZDV-associated mutations (median: 1 vs. 2; p =.09). No subject with greater than one ZDV mutation had a virologic response to d4T. Seven of the 8 responders had only a K70R mutation at baseline. We conclude that in patients with prior ZDV treatment, those with only one ZDV mutation, particularly at position 70, can still get reasonable virologic activity from d4T. Those with more mutations are not likely to have much benefit.