Prevalence Of K65R Research Articles

An association between K65R and HIV-1 subtype C viruses in patients treated with multiple NRTIs.

Objectives: HIV-1 subtype C might have a greater propensity to develop K65R mutations in patients with virological failure compared with other subtypes. However, the strong association between viral subtype and confounding factors such as exposure groups and ethnicity affects the calculation of this propensity. We exploited the diversity of viral subtypes within the UK to undertake a direct comparative analysis. Patients and methods: We analysed only sequences with major IAS-defined mutations from patients with virological failure. Prevalence of K65R was related to subtype and exposure to the NRTIs that primarily select for this mutation (tenofovir, abacavir, didanosine and stavudine). A multivariate logistic regression model quantified the effect of subtype on the prevalence of K65R, adjusting for previous and current exposure to all four specified drugs. Results: Subtype B patients (n = 3410) were mostly MSM (78%) and those with subtype C (n = 810) were mostly heterosexual (82%). K65R was detected in 7.8% of subtype B patients compared with 14.2% of subtype C patients. The subtype difference in K65R prevalence was observed irrespective of NRTI exposure and K65R was frequently selected by abacavir, didanosine and stavudine in patients with no previous exposure to tenofovir. Multivariate logistic regression confirmed that K65R was significantly more common in subtype C viruses (adjusted OR = 2.02, 95% CI = 1.55–2.62, P < 0.001). Conclusions: Patients with subtype C HIV-1 have approximately double the frequency of K65R in our database compared with other subtypes. The exact clinical implications of this finding need to be further elucidated.

PREVALENCE OF DRUG RESISTANT HIV STRAINS IN HIV-INFECTED PATIENTS OF REPRODUCTIVE AGE

The prevalence of drug resistant HIV strains among HIV-positive reproductive aged persons with ineffective antiretroviral therapy (ART) was assessed. The prevalence of drug resistant strains of HIV was 73.8% in the group of women and 89.29% in the group of men (totally in 80.0% of patients). In the spectrum of drug resistance mutations (DRMs) the most prevalent mutation associated with high-level resistance to nucleoside reverse transcriptase inhibitors was substitution M184V (80.36%); in addition, the high prevalence of K65R (26.79%) was indicated. The most common mutations causing a high-level resistance to nonnucleoside reverse transcriptase inhibitors were G190S/A (57.14%), Y181C (37.50%), K101E (33.93%). The DRMs to protease inhibitors were indicated with significantly less frequent (5.36%).

Resistance at Virological Failure Using Boosted Protease Inhibitors Versus Nonnucleoside Reverse Transcriptase Inhibitors As First-Line Antiretroviral Therapy—Implications for Sustained Efficacy of ART in Resource-Limited Settings

Increases in the prevalence of resistance to nonnucleoside reverse transcriptase inhibitors (NNRTIs) have been observed among previously untreated individuals in all areas of sub-Saharan Africa. We aimed to examine whether first-line use of 2 NRTIs plus a boosted protease inhibitor (bPI) could protect against emergence of NRTI resistance mutations, compared to the use of 2 NRTIs plus 1 NNRTI. We carried out a weighted meta-analysis of randomized clinical trials comparing bPI- with NNRTI-based first-line antiretroviral therapy regimens using random effects modeling. In intention to treat analyses, there was no difference in the risk of viral failure at week 48 between NNRTI and bPI (P = .19). At week 48, the overall difference between NNRTI- and PI-based regimens in selection of any major NRTI resistance mutation (crude unweighted prevalence 3.3% vs 1.6%) was 1.7% (95% confidence interval [CI], .4-3.0; P = .00927). There was a statistically significant difference in prevalence of K65R when comparing NNRTI (1.3%) with PI (0.67%); absolute weighted difference 1.0% (95% CI, .3-1.7; P = .00447). There was also a significant difference in prevalence of M184V/I between NNRTI and PI (crude unweighted prevalence 3.2% vs 1.4%); difference 1.6% (95% CI 0.1-3.1; P = .0368). Despite the equivalent efficacy and more favorable resistance implications of PI- versus NNRTI-based first line therapy, widespread use of PI-based first-line therapy is not warranted at this time, due to resource limitations and predicted increased risk of resistance-related failure of NNRTI/NRTI second-line regimens. PI-based first-line therapy could be reconsidered when antiretroviral agents from other classes become available for second-line regimens in resource-limited settings.

Prevalence of pre-existing resistance-associated mutations to rilpivirine, emtricitabine and tenofovir in antiretroviral-naive patients infected with B and non-B subtype HIV-1 viruses

The prevalence of rilpivirine, emtricitabine and tenofovir resistance-associated mutations (RAMs), described in vitro and in vivo, was determined in antiretroviral-naive patients. From 2008 to 2011, 1729 treatment-naive patients were tested for resistance by bulk sequencing. We studied the primary rilpivirine RAMs (K101E/P, E138A/G/K/Q/R, V179L, Y181C/I/V, H221Y, F227C and M230I/L) and other potential rilpivirine-associated mutations (V90I, L100I, K101T, E138S, V179D/I, Y188L, V189I, G190A/E/S and M230V). We also studied the M184V/I and K65R mutations for emtricitabine and tenofovir, respectively. Among 1729 sequences, half of patients had B-subtype viruses and the other half non-B (with 26.7% CRF02, n=461). Primary rilpivirine RAMs were infrequent (4.6%, n=79) and the most prevalent were E138A (3%, n=52), E138K, (0.3%, n=5), H221Y (0.3%, n=5), E138G (0.2%, n=4) and Y181C (0.2%, n=4). The frequency of the primary rilpivirine RAMs was similar between B and non-B subtypes. The other potential rilpivirine-associated mutations that were most prevalent were V179I (8.4%, n=145), V90I (3.8%, n=65) and V189I (2.3%, n=40). The common V179I, V189I and V90I polymorphisms have not been associated with virological failure in Phase 3 clinical studies. By the ANRS algorithm, 4.9% (n=84) of samples were resistant to rilpivirine, 3.7% (n=32) of B-subtype viruses versus 6% (n=52) of non-B-subtype viruses (P=0.02, χ(2) test). The prevalence of K65R and M184I/V was 0.06% (1/1729) and 1% (18/1729), respectively. The prevalence of K103N was 2% (35/1729). The prevalence of rilpivirine, emtricitabine and tenofovir resistance mutations was very low in antiretroviral-naive patients. The prevalence of resistance to rilpivirine (4.9%, n=84) was not statistically different from the prevalence of efavirenz and nevirapine resistance in our population.

Low prevalence of transmitted K65R and other tenofovir resistance mutations across different HIV‐1 subtypes: implications for pre‐exposure prophylaxis

IntroductionTenofovir-containing regimens have demonstrated potential efficacy as pre-exposure prophylaxis (PrEP) in preventing HIV-1 infection. Transmitted drug resistance mutations associated with tenofovir, specifically the reverse transcriptase (RT) mutation K65R, may impact the effectiveness of PrEP. The worldwide prevalence of transmitted tenofovir resistance in different HIV-1 subtypes is unknown.MethodsSequences from treatment-naïve studies and databases were aggregated and analyzed by Stanford Database tools and as per the International AIDS Society (IAS-USA) resistance criteria. RT sequences were collected from GenBank, the Stanford HIV Sequence Database and the Los Alamos HIV Sequence Database. Sequences underwent rigorous quality control measures. Tenofovir-associated resistance mutations included K65R, K70E, T69-insertion and ≥3 thymidine analogue mutations (TAMs), inclusive of M41L or L210W.ResultsA total of 19,823 sequences were evaluated across diverse HIV-1 subtypes (Subtype A: 1549 sequences, B: 9783, C: 3198, D: 483, F: 372, G: 594, H: 41, J: 69, K: 239, CRF01_AE: 1797 and CRF02_AG: 1698). Overall, tenofovir resistance prevalence was 0.4% (n=77/19,823, 95% confidence interval or CI: 0.3 to 0.5). K65R was found in 20 sequences (0.1%, 95% CI: 0.06 to 0.15). Differences in the prevalence of K65R between HIV-1 subtypes were not statistically significant. K70E and ≥3 TAMs were found in 0.015% (95% CI: 0.004 to 0.04) and 0.27% (95% CI: 0.2 to 0.4) of sequences, respectively.ConclusionsPrevalence of transmitted K65R and other tenofovir resistance mutations across diverse HIV-1 subtypes and recombinants is low, suggesting minimal effect on tenofovir-containing PrEP regimens.

HIV-1 drug resistance patterns among treatment-naïve and therapy-experienced patients in Poland

Summary Background HIV-1 drug resistance (DR) is becoming a growing concern. It is estimated that about one out of ten newly HIV-infected persons in Europe acquires HIV-1 drug resistant strain. DR testing is now believed to play a crucial role in proper and successful treatment. The aim of the study was a retrospective analysis of the HIV-1 drug resistance patterns among Polish naive and therapy-experienced patients. Materials and methods In all cases before drug resistance testing viral load was determined as well as CD4/CD8 counts. The sequencing assay was carried out using commercially available assays according to manufacturer's protocol. Electrophoretic analysis data were verified and manually corrected. Interpretation was performed using Stanford's Genotypic Resistance Interpretation Algorithm or by a built-in algorithm included in ViroSeq System. Results In the treatment-naive group 14,1% of tested patients have acquired HIV-1 strains harbouring resistance-associated mutations. In the therapy-experienced group among 75 analyzed patients 58 (77%) were found to be carrying drug resistant mutants. In this group 14 persons (19%) had at least one resistance-associated mutation in all three drug classes. Among therapy-experienced patients the prevalence of K65R was very low (1,3%). Conclusion The results of both analysed groups indicate the necessity of resistance testing in Poland. In the group of patients never exposed to ART in 14,1% cases viral variants resistant to at least one of the drugs were identified. The problem of resistance intensifies with consecutive regimen failures limiting the remaining treatment options. A shift has been observed in the route of HIV-1 infection in Poland. The obtained data also documents a change in HIV subtype pattern in Poland. The low prevalence of K65R mutation may result in very potent salvage therapy options based on TDF. Presented data documents high prevalence of drug resistance in Poland and justifies the necessity of DR testing.

HIV‐1 reverse transcriptase (RT) genotypic patterns and treatment characteristics associated with the K65R RT mutation

The K65R HIV-1 reverse transcriptase (RT) mutation is a multidrug resistance mutation which may be correlated with specific antiretroviral combinations and with the presence or absence of other RT resistance mutations. The aims of this study were: (i) to determine the prevalence of the K65R mutation in a cohort of antiretroviral-treated patients; (ii) to study genotypic patterns and treatment characteristics in patients in whom the K65R mutation was present. We included in the study all antiretroviral-experienced patients followed up at the Bordeaux University Hospital in 2003 and 2004 for whom an HIV-1 genotypic resistance analysis was available. Information on RT resistance mutations was reported from a hospital database including therapeutic and biological parameters. The prevalence of K65R was investigated for all patients. Genotypic patterns and treatment characteristics were examined at the time of detection of the K65R mutation. The prevalence of K65R was 1.9% (26 of 1404 patients). K65R was associated with nucleoside RT inhibitor-based regimens in 22 patients, and with tenofovir disoproxil fumarate, lamivudine, didanosine and abacavir in 23, 17, 17 and eight patients, respectively. The M184V and Q151M mutations were the most commonly co-selected substitutions. Thymidine analogue mutations (TAMs) were rarely co-selected with K65R and inversely associated with K65R. The K65R mutation may emerge preferentially in the absence of zidovudine and TAMs, suggesting the possibility of an antagonistic interaction between K65 and TAMs.