Low-frequency K103N strengthens the impact of transmitted drug resistance on virologic responses to first-line efavirenz or nevirapine-based highly active antiretroviral therapy.
ABSTRACT There are conflicting data on the impact of low-frequency transmitted drug-resistant mutants on responses to first-line highly active antiretroviral therapy (HAART).
Patients started nevirapine or efavirenz with two or more nucleoside/nucleotide reverse transcriptase inhibitors in 1998-2007 without a prior resistance test at a median 1.0 (interquartile range, 0.0-3.4) year after diagnosis and with a median 218 (interquartile range, 131-296) CD4 cells/mm3, and had at least 24 weeks of follow up. Pre-HAART plasma samples were tested retrospectively by bulk genotyping and sensitive real-time polymerase chain reaction targeting reverse transcriptase K65R, K103N, Y181C, M184V, and G190A (interpretative cutoff 0.3%-0.9%).
Among 93 patients, seven of 18 who experienced virologic failure and zero of 75 who maintained virologic suppression showed pre-HAART resistance, including three with high-frequency mutations detectable by bulk genotyping (two K103N, one G190A) and four with low-frequency K103N detectable only by polymerase chain reaction. Detection of either bulk (P = 0.006) or low-frequency (P = 0.001) resistance was significantly associated with the odds of virologic failure; combining the two markedly increased the strength of the association (P < 0.0001). At failure, the pre-HAART mutations were detected by bulk genotyping in five of seven patients alongside additional reverse transcriptase mutations.
Low-frequency K103N mutants were as prevalent as bulk-detectable variants before starting HAART. Both high- and low-frequency mutants were significantly associated with virologic failure.
SourceAvailable from: Amogne Wondwossen[Show abstract] [Hide abstract]
ABSTRACT: Objective: To assess the presence of two major non-nucleoside reverse transcriptase inhibitors (NNRTI) drug resistance mutations (DRMs), Y181C and K103N, in minor viral quasispecies of treatment naive HIV-1 infected East-African and Swedish patients by allele-specific polymerase chain reaction (AS-PCR). Methods: Treatment naive adults (n = 191) with three epidemiological backgrounds were included: 92 Ethiopians living in Ethiopia; 55 East-Africans who had migrated to Sweden; and 44 Caucasians living in Sweden. The pol gene was analysed by standard population sequencing and by AS-PCR for the detection of Y181C and K103N. Results: The Y181C was detected in the minority quasispecies of six Ethiopians (6.5%), in two Caucasians (4.5%), and in one East-African (1.8%). The K103N was detected in one East-African (1.8%), by both methods. The proportion of mutants ranged from 0.25% to 17.5%. Additional DRMs were found in all three treatment naive patient groups by population sequencing. Conclusions: Major NNRTI mutations can be found by AS-PCR in minor quasispecies of treatment naive HIV-1 infected Ethiopians living in Ethiopia, in East-African and Caucasian patients living in Sweden in whom population sequencing reveal wild-type virus only. Surveys with standard sequencing are likely to underestimate transmitted drug resistance and the presence of resistant minor quasispecies in treatment naive patients should be topic for future large scale studies.PLoS ONE 10/2014; 9(10):e111042. DOI:10.1371/journal.pone.0111042 · 3.53 Impact Factor
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ABSTRACT: Low-frequency HIV variants possessing resistance mutations against non‑nucleoside reverse transcriptase inhibitors (NNRTI), especially at HIV reverse transcriptase (RT) amino acid (aa) positions K103 and Y181, have been shown to adversely affect treatment response. Therapeutic failure correlates with both the mutant viral variant frequency and the mutational load. We determined the prevalence of NNRTI resistance mutations at several RT aa positions in viruses from 204 antiretroviral (ARV)-naïve HIV-infected individuals using deep sequencing, and examined the relationship between mutant variant frequency and mutational load for those variants. Deep sequencing to ≥0.4% levels found variants with major NNRTI-resistance mutations having a Stanford-HIVdb algorithm value ≥30 for efavirenz and/or nevirapine in 52/204 (25.5%) ARV-naïve HIV-infected persons. Eighteen different major NNRTI mutations were identified at 11 different positions, with the majority of variants being at frequency >1%. The frequency of these variants correlated strongly with the mutational load, but this correlation weakened at low frequencies. Deep sequencing detected additional major NNRTI-resistant viral variants in treatment-naïve HIV-infected individuals. Our study suggests the significance of screening for mutations at all RT aa positions (in addition to K103 and Y181) to estimate the true burden of pre-treatment NNRTI-resistance. An important finding was that variants at low frequency had a wide range of mutational loads (>100-fold) suggesting that frequency alone may underestimate the impact of specific NNRTI-resistant variants. We recommend further evaluation of all low-frequency NNRTI-drug resistant variants with special attention given to the impact of mutational loads of these variants on treatment outcomes.Viruses 09/2014; 6(9):3428-3437. DOI:10.3390/v6093428 · 3.28 Impact Factor
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ABSTRACT: Worldwide circulating HIV-1 genomes show extensive variation represented by different subtypes, polymorphisms and drug-resistant strains. Reports on the impact of sequence variation on antiretroviral therapy (ART) outcomes are mixed. In this review, we summarize relevant published data from both resource-rich and resource-limited countries in the last 10 years on the impact of HIV-1 sequence diversity on treatment outcomes. The prevalence of transmission of drug resistant mutations (DRMs) varies considerably, ranging from 0% to 27% worldwide. Factors such as geographic location, access and availability to ART, duration since inception of treatment programs, quality of care, risk-taking behaviors, mode of transmission, and viral subtype all dictate the prevalence in a particular geographical region. Although HIV-1 subtype may not be a good predictor of treatment outcome, review of emerging evidence supports the fact that HIV-1 genome sequence-resulting from natural polymorphisms or drug-associated mutations-matters when it comes to treatment outcomes. Therefore, continued surveillance of drug resistant variants in both treatment-naïve and treatment-experienced populations is needed to reduce the transmission of DRMs and to optimize the efficacy of the current ART armamentarium.Viruses 10/2014; 6(10):3855-3872. DOI:10.3390/v6103855 · 3.28 Impact Factor