Resistance patterns selected by nevirapine vs. efavirenz in HIV-infected patients failing first-line antiretroviral treatment: a bayesian analysis

Biophysical Characterization of Novel DNA Aptamers against K103N/Y181C Double Mutant HIV-1 Reverse Transcriptase

The human immunodeficiency virus type-1 Reverse Transcriptase (HIV-1 RT) plays a pivotal role in essential viral replication and is the main target for antiviral therapy. The anti-HIV-1 RT drugs address resistance-associated mutations. This research focused on isolating the potential specific DNA aptamers against K103N/Y181C double mutant HIV-1 RT. Five DNA aptamers showed low IC50 values against both the KY-mutant HIV-1 RT and wildtype (WT) HIV-1 RT. The kinetic binding affinity forms surface plasmon resonance of both KY-mutant and WT HIV-1 RTs in the range of 0.06–2 μM and 0.15–2 μM, respectively. Among these aptamers, the KY44 aptamer was chosen to study the interaction of HIV-1 RTs-DNA aptamer complex by NMR experiments. The NMR results indicate that the aptamer could interact with both WT and KY-mutant HIV-1 RT at the NNRTI drug binding pocket by inducing a chemical shift at methionine residues. Furthermore, KY44 could inhibit pseudo-HIV particle infection in HEK293 cells with nearly 80% inhibition and showed low cytotoxicity on HEK293 cells. These together indicated that the KY44 aptamer could be a potential inhibitor of both WT and KY-mutant HIV-RT.

Antiretroviral treatment adherence and mental disorders: observational case-control study in people living with HIV in Spain

Mental disorders hamper immunological control of HIV infection by exerting a negative influence on antiretroviral therapy (ART) adherence. We sought to address the possible relationship between non-adherence to antiretroviral treatment (ART), mental disorders and substance use in people living with HIV/AIDS (PLWHA) in Spain, which presents a high prevalence of intravenously transmitted HIV infection. We assessed 125 PLWHA attending regular outpatient follow-up. The main adherence measure was pill collection from the Hospital Pharmacy. We included sociodemographic variables, mental disorders diagnosis, and substance use in the 12 months prior to the assessment. Harmful alcohol consumption (OR: 6.834; 95% CI: 2.008-23.257; p = 0.002), suffering from depression (OR: 5.851; 95% CI: 1.470-23.283; p = 0.012) and being at risk of suicide (OR: 3.495; 95% CI: 1.136-10.757; p = 0.029) increased the likelihood of non-adherence. 29.6% of the sample had been infected via blood contact. HCV co-infection was present in 46.4% of the study sample, increasing the likelihood of non-adherence (OR: 3.223; 95% CI: 1.119-9.286; p = 0.030). Harmful alcohol use and some serious mental disorders (especially depression and suicide risk) are consistently associated with non-adherence to ART. HCV co-infection could be an important risk marker of non-adherence among PLWHA with a high prevalence of intravenous drug use.

Personality and adherence to antiretroviral therapy in HIV-infected adult patients

OBJECTIVE

Antiretroviral therapy (ART) has been able to transform HIV infection into a chronic disease. However, ART adherence remains an important barrier and personality traits have been postulated as a factor to be considered. This study aims to identify personality traits that can affect ART adherence, taking into account other potentially influencing factors.

METHODS

Case-control study. Controls and cases were classified using the percentage ART dispensation as recorded in the Hospital Pharmacy database. Controls were defined as people living with HIV/AIDS (PLWHA) with percentage ART dispensation during the last year >95% and cases were defined as PLWHA with percentage ART dispensation during the last year <90%. Sociodemographic, clinical parameters of HIV infection, psychopathological and neuropsychological factors were collected. Personality was assessed using the NEO PI-R Personality Inventory, questionnaire based on the Five Factor Model of Personality. Statistical analysis was performed using logistic regression (SPSS v.22).

RESULTS

125 PLWHA were included: 79 controls and 46 cases. After adjusting for confounding variables, logistic regression analysis showed that poor adherence was associated with Neuroticism (OR 1.2, 95%CI: 1.021-1.385) and Impulsivity (N5) (OR 1.5, 95%CI: 1.066-2.163). In contrast, each additional point in Order (C2) (OR 0.8, 95%CI: 0.679-0.992) or Values (O6) (OR 0.8, 95%CI: 0.710-0.974) were associated with good ART adherence.

CONCLUSIONS

Personality is a variable to be considered in ART adherence. Implementation of the personality in the assessment of PLWHA helps identify those individuals potentially more likely to exhibit poorer ART adherence.

OLA-Simple: A software-guided HIV-1 drug resistance test for low-resource laboratories

Background

HIV drug resistance (HIVDR) testing can assist clinicians in selecting treatments. However, high complexity and cost of genotyping assays limit routine testing in settings where HIVDR prevalence has reached high levels.

Methods

The oligonucleotide ligation assay (OLA)-Simple kit was developed for detection of HIVDR against first-line non-nucleoside/nucleoside reverse transcriptase inhibitors and validated on 672 codons (168 specimens) from subtypes A, B, C, D, and AE. The kit uses dry reagents to facilitate assay setup, lateral flow devices for visual HIVDR detections, and in-house software with an interface for guiding users and analyzing results.

Findings

HIVDR analysis of specimens by OLA-Simple compared to Sanger sequencing revealed 99.6 ± 0.3% specificity and 98.2 ± 0.9% sensitivity, and compared to high-sensitivity assays, 99.6 ± 0.6% specificity and 86.2 ± 2.5% sensitivity, with 2.6 ± 0.9% indeterminate results. OLA-Simple was performed more rapidly compared to Sanger sequencing (<4 h vs. 35–72 h). Forty-one untrained volunteers blindly tested two specimens each with 96.8 ± 0.8% accuracy.

Interpretation

OLA-Simple compares favorably with HIVDR genotyping by Sanger and sensitive comparators. Instructional software enabled inexperienced, first-time users to perform the assay with high accuracy. The reduced complexity, cost, and training requirements of OLA-Simple could improve access to HIVDR testing in low-resource settings and potentially allow same-day selection of appropriate antiretroviral therapy.

Fund

USA National Institutes of Health R01; the Clinical and Retrovirology Research Core and the Molecular Profiling and Computational Biology Core of the UW CFAR; Seattle Children's Research Institute; UW Holloman Innovation Challenge Award; Pilcher Faculty Fellowship.

Variability of efavirenz plasma concentrations among pediatric HIV patients treated with efavirenz based combination antiretroviral therapy in Dar es Salaam, Tanzania

Background

Children are subject to varying drug pharmacokinetics which influence plasma drug levels, and hence treatment outcomes especially for drugs like efavirenz whose plasma concentrations are directly related to treatment outcomes. This study is aimed at determining plasma efavirenz concentrations among Tanzanian pediatric HIV-1 patients on efavirenz-based combination antiretroviral therapy (cART) and relating it to clinical, immunological and virologic treatment responses.

Methods

A cross sectional study involving pediatric HIV patients aged 5–15 years on efavirenz-based cART for ≥ 6 months were recruited in Dar es Salaam. Data on demographics, cART regimens, efavirenz dose and time of the last dose were collected using structured questionnaires and checklists. Venous blood samples were drawn at 10–19 h post-dosing for efavirenz plasma analysis.

Results

A total of 145 children with a mean ± SD age of 10.83 ± 2.75 years, on cART for a mean ± SD of 3.7 ± 2.56 years were recruited. Median [IQR] efavirenz concentration was 2.56 [IQR = 1.5–4.6] μg/mL with wide inter-patient variability (CV 111%). Poor virologic response was observed in 70.8%, 20.8% and 15.9% of patients with efavirenz levels < 1 μg/mL, 1–4 μg/mL and > 4 μg/mL respectively. Patients with efavirenz levels of < 1 μg/mL were 11 times more likely to have detectable viral loads. Immunologically, 31.8% of children who had low levels (< 1 μg/mL) of efavirenz had a CD4 count of < 350 cells/μL.

Conclusion

Wide inter-individual variability in efavirenz plasma concentrations is seen among Tanzanian children in routine clinical practice with many being outside the recommended therapeutic range. Virologic failure is very high in children with sub-therapeutic levels. Concentrations outside the therapeutic window suggest the need for dose adjustment on the basis of therapeutic drug monitoring to optimize treatment.

Cytochrome P450 2B6 genetic variants are associated with plasma nevirapine levels and clinical response in HIV-1 infected Kenyan women: a prospective cohort study

Background

Polymorphisms in cytochrome P450 2B6 (CYP2B6) affect the steady state plasma concentration of nevirapine. CYP2B6 516G>T and 983T>C are common in African populations, but data on their influence on plasma nevirapine concentration and clinical response in African women are limited. We investigated the impact of CYP 516G>T and 983T>C on plasma nevirapine concentration and clinical outcomes in a prospective cohort study of HIV-infected Kenyan women.

Methods

Study subjects were 66 HIV-1-seropositive women taking nevirapine-based antiretroviral therapy. Plasma collected at week 12 was analyzed for nevirapine concentration by high performance liquid chromatography. Baseline samples were genotyped for CYP2B6 516G>T and 983T>C single nucleotide polymorphisms by real-time polymerase chain reaction. CD4 cell count, plasma viral load, and genotypic drug resistance in plasma and genital secretions were assessed at baseline and during follow up. We evaluated the effect of each genotype on plasma nevirapine concentration at week 12 and on change in CD4 cell count at months 3, 6 and 12. Associations between plasma nevirapine concentration and clinical outcomes were analyzed by logistic or linear regression.

Results

Women with CYP2B6 516TT genotype (n=9) had higher mean nevirapine plasma levels (14.33 μg/mL) compared to those with heterozygous 516GT (9.18 μg/mL; n=25) and wild- type 516GG (7.95 μg/mL; n=32) genotypes (P=0.01). Women heterozygous for the CYP2B6 983TC genotype (n=13) had higher mean nevirapine plasma levels (12.94 μg/mL), compared to women with the homozygous 983TT (8.35 μg/mL; n=53) genotype (P=0.007). In Generalized Estimating Equation analysis, plasma nevirapine levels predicted greater change in CD4 cell count after ART initiation (adjusted beta 119.4 cells/μL, 95% CI, 27.3–211.5 cells/μL, P=0.01). The CYP2B6 983TT genotype also predicted greater change in CD4 cell count (adjusted beta 68.6 cells/μL, 95% CI, 3.9–133.4 cells/μL, P=0.04). We found no associations between CYP2B6 genotypes and virologic response or toxicity.

Conclusions

CYP2B6 516G>T and CYP2B6 983T>C genotypes were strongly associated with plasma nevirapine concentration, which predicted immunologic response in women on nevirapine-based antiretroviral therapy. These data support continued work on the potential utility of human genetic testing to inform nevirapine dosage optimization for individual patients.

Two-year outcome of first-line antiretroviral therapy among HIV-1 vertically-infected children in Hanoi, Vietnam

A retrospective analysis of 86 HIV-1 vertically-infected Vietnamese children with a follow-up period >24 months after initiating antiretroviral therapy (ART) was performed from 2008 to 2012, to assess the outcome of first-line ART in resource-limited settings. Of the 86 children, 68 (79.1%) were treated successfully (plasma HIV-1 viral load [VL] <1000 copies/ml), and 63 (73.3%) had full viral suppression (VL <400 copies/ml) after 24 months of ART. No significant difference between successfully treated patients and failure groups was observed in VL, CD4(+) T-cell count or clinical stage at baseline; age at ART start; or ART regimen. All 14 children with VL >5000 copies/ml, one of four children with VL 1000-5000 copies/ml and none with VL <1000 copies/ml developed reverse transcriptase inhibitor (RTI)-resistance mutations by 24 months of ART. Y181C and M184V/I were the most dominant non-nucleoside and nucleoside RTI-resistance mutations, respectively (13/15, 86.7%). These findings suggest that VL testing after 24 months of ART can be used to efficiently differentiate ART failures among HIV-1 vertically-infected children in resource-limited settings.

Virological failure and HIV-1 drug resistance mutations among naive and antiretroviral pre-treated patients entering the ESTHER program of Calmette Hospital in Cambodia

Introduction

In resource limited settings, patients entering an antiretroviral therapy (ART) program comprise ART naive and ART pre-treated patients who may show differential virological outcomes.

Methods

This retrospective study, conducted in 2010–2012 in the HIV clinic of Calmette Hospital located in Phnom Penh (Cambodia) assessed virological failure (VF) rates and patterns of drug resistance of naive and pre-treated patients. Naive and ART pre-treated patients were included when a Viral Load (VL) was performed during the first year of ART for naive subjects or at the first consultation for pre-treated individuals. Patients showing Virological failure (VF) (>1,000 copies/ml) underwent HIV DR genotyping testing. Interpretation of drug resistance mutations was done according to 2013 version 23 ANRS algorithms.

Results

On a total of 209 patients, 164 (78.4%) were naive and 45 (21.5%) were ART pre-treated. Their median initial CD4 counts were 74 cells/mm³ (IQR: 30–194) and 279 cells/mm³ (IQR: 103–455) (p<0.001), respectively. Twenty seven patients (12.9%) exhibited VF (95% CI: 8.6–18.2%), including 10 naive (10/164, 6.0%) and 17 pre-treated (17/45, 37.8%) patients (p<0.001). Among these viremic patients, twenty-two (81.4%) were sequenced in reverse transcriptase and protease coding regions. Overall, 19 (86.3%) harbored ≥1 drug resistance mutations (DRMs) whereas 3 (all belonging to pre-treated patients) harbored wild-types viruses. The most frequent DRMs were M184V (86.3%), K103N (45.5%) and thymidine analog mutations (TAMs) (40.9%). Two (13.3%) pre-treated patients harbored viruses that showed a multi-nucleos(t)ide resistance including Q151M, K65R, E33A/D, E44A/D mutations.

Conclusion

In Cambodia, VF rates were low for naive patients but the emergence of DRMs to NNRTI and 3TC occurred relatively quickly in this subgroup. In pre-treated patients, VF rates were much higher and TAMs were relatively common. HIV genotypic assays before ART initiation and for ART pre-treated patients infection should be considered as well.

Successful switch to rilpivirine/tenofovir/emtricitabine in HIV-1-infected patients with an isolated K103N mutation acquired during prior nonnucleoside reverse transcriptase inhibitor therapy

OBJECTIVES

Whether treatment-experienced HIV-1-infected patients with an acquired K103N mutation after failing nonnucleoside reverse transcriptase inhibitor (NNRTI) regimens can be treated with rilpivirine is unknown. The aim of this pilot study was to evaluate the efficacy of rilpivirine/tenofovir/emtricitabine in HIV-1-infected patients with an isolated K103N mutation.

METHODS

A prospective study was carried out in HIV-1-infected adults who acquired the K103N mutation on failing NNRTI regimens. No other mutations in reverse transcriptase were allowed. Patients had to be on second-line regimens with HIV-1 RNA < 200 copies/mL for ≥ 6 months. Exclusion criteria were: use of acid-reducing agents, insufficient caloric intake and impaired renal function. Of primary interest was virological success (HIV-1 RNA < 200 copies/mL) at weeks 6, 12, 24 and 48.

RESULTS

Of 1550 HIV-1-infected patients at the Erasmus Medical Center Rotterdam, we identified 10 HIV-1-infected patients with an isolated K103N mutation acquired after NNRTI failure. Five patients were not eligible for inclusion in the study, and two patients refused participation. Three African women (23-35 years of age) were included and were switched from boosted protease inhibitor-based second-line therapies to rilpvirine/tenofovir/emtricitabine. HIV-1 RNA was < 200 copies/mL at weeks 6, 12, 24 and 48 for all patients. No adverse events were observed. All patients had HIV-1 RNA < 200 copies/mL for 6-50 months prior to the switch.

CONCLUSIONS

This pilot study demonstrates the successful switch of HIV-1-infected patients who acquired an isolated K103N mutation during previous NNRTI therapy to rilpivirine/tenofovir/emtricitabine. In selected patients, single-tablet regimens are also becoming a valid treatment option for second-line HIV-1 therapy.

Emergence of HIV drug resistance during first- and second-line antiretroviral therapy in resource-limited settings

INTRODUCTION

Antiretroviral therapy (ART) in resource-limited settings has expanded in the last decade, reaching >8 million individuals and reducing AIDS mortality and morbidity. Continued success of ART programs will require understanding the emergence of HIV drug resistance patterns among individuals in whom treatment has failed and managing ART from both an individual and public health perspective. We review data on the emergence of HIV drug resistance among individuals in whom first-line therapy has failed and clinical and resistance outcomes of those receiving second-line therapy in resource-limited settings.

RESULTS

Resistance surveys among patients initiating first-line nonnucleoside reverse-transcriptase inhibitor (NNRTI)-based therapy suggest that 76%-90% of living patients achieve HIV RNA suppression by 12 months after ART initiation. Among patients with detectable HIV RNA at 12 months, HIV drug resistance, primarily due to M184V and NNRTI mutations, has been identified in 60%-72%, although the antiretroviral activity of proposed second-line regimens has been preserved. Complex mutation patterns, including thymidine-analog mutations, K65R, and multinucleoside mutations, are prevalent among cases of treatment failure identified by clinical or immunologic methods. Approximately 22% of patients receiving second-line therapy do not achieve HIV RNA suppression by 6 months, with poor adherence, rather than HIV drug resistance, driving most failures. Major protease inhibitor resistance at the time of second-line failure ranges from 0% to 50%, but studies are limited.

CONCLUSIONS

Resistance of HIV to first-line therapy is predictable at 12 months when evaluated by means of HIV RNA monitoring and, when detected, largely preserves second-line therapy options. Optimizing adherence, performing resistance surveillance, and improving treatment monitoring are critical for long-term prevention of drug resistance.

Extensive drug resistance in HIV-infected Cambodian children who are undetected as failing first-line antiretroviral therapy by WHO 2010 guidelines

Antiretroviral therapy in resource-limited settings is monitored clinically and immunologically according to WHO guidelines. Frequent misclassification of virologic failure is reported, mostly in adults, leading to early therapy switch or late failure diagnosis. Pediatric treatment monitoring and resistance data upon first-line failure are limited, particularly when the 2010-WHO pediatric guidelines are used without routine viral load monitoring. We previously reported high treatment failure misclassification rates by pediatric 2010 guidelines in Cambodian children on first-line therapy. Here we determine the extent and patterns of resistance, with yearly viral load and 6-monthly CD4. Drug resistance mutations were determined using the IAS-USA 2011 list. Predicted resistance interpretation was determined with Stanford Database tools. Fifty-one children with available genotypes met inclusion criteria. All but one (subtype B) were CRF01_AE. The most common regimen was stavudine, lamivudine, and nevirapine (96%), taken for a median of 2.2 years. Resistance was seen in 98%; 96% to nucleoside and nonnucleoside reverse transcriptase inhibitors (NRTIs and NNRTIs); 51% with ≥4 mutations. The most common NRTI mutations were 184V/I and 67N and the most common NNRTI mutations were 181C/Y/I/V and 190A/S. A total of 22% had multiresistant mutations and 18% had predicted high-level resistance to subsequent therapy options didanosine, abacavir, etravirine, and tenofovir. In 98% of Cambodian children misclassified as nonfailing first-line therapy by 2010 guidelines, 51% had extensive drug resistance to current and 18% to subsequent antiretroviral therapy. Affordable routine viral load monitoring allowing for early and more accurate treatment failure diagnosis is desperately needed in resource-limited settings.

Impact of minority nonnucleoside reverse transcriptase inhibitor resistance mutations on resistance genotype after virologic failure

Drug-resistant human immunodeficiency virus type 1 (HIV-1) minority variants increase the risk of virologic failure for first-line nonnucleoside reverse transcriptase inhibitor (NNRTI)-based regimens. We performed a pooled analysis to evaluate the relationship between NNRTI-resistant minority variants and the likelihood and types of resistance mutations detected at virologic failure. In multivariable logistic regression analysis, higher NNRTI minority variant copy numbers, non-white race, and nevirapine use were associated with a higher risk of NNRTI resistance at virologic failure. Among participants on efavirenz, K103N was the most frequently observed resistance mutation at virologic failure regardless of the baseline minority variant. However, the presence of baseline Y181C minority variant was associated with a higher probability of Y181C detection after virologic failure. NNRTI regimen choice and preexisting NNRTI-resistant minority variants were both associated with the probability and type of resistance mutations detected after virologic failure.

Pharmacological and clinical evidence of nevirapine immediate- and extended-release formulations

We reviewed the current information available on nevirapine immediate- and extended-release formulations and its role in single-dose and combination antiretroviral therapy. Nevirapine was approved in 1996 and was the first non-nucleoside reverse-transcriptase inhibitor available for the treatment of HIV-1 infection. Nevirapine has demonstrated good efficacy and a well-characterized safety profile. A major drawback is the low genetic barrier, allowing the emergence of resistance in the presence of single mutations in the reverse-transcriptase gene. This shortcoming is particularly relevant when nevirapine is administered in a single dose to prevent mother-to-child transmission of HIV-1 infection, compromising the efficacy of future non-nucleoside reverse transcriptase-inhibitor regimens. Studies published recently have probed the noninferiority of nevirapine compared to ritonavir-boosted atazanavir with both tenofovir disoproxil fumarate and emtricitabine in antiretroviral treatment-naïve patients. In 2011, a new formulation of nevirapine (nevirapine extended release) that allowed once-daily dosing was approved by the Food and Drug Administration and by the European Medicines Agency. VERxVe, a study comparing nevirapine extended release with nevirapine immediate release in antiretroviral treatment-naïve patients, and TRANxITION, a study carried out in antiretroviral treatment-experienced patients who switched therapy from nevirapine immediate release to nevirapine extended release, provided data on the noninferiority of the new formulation of nevirapine compared with nevirapine immediate release in terms of efficacy and safety. Nevirapine extended release will further increase the durability and persistence of nevirapine-containing antiretroviral therapy, allowing once-daily dosing regimens.

No increase of drug-resistant HIV type 1 prevalence among drug-naive individuals in Northern Vietnam

We reported previously that the prevalence of drug-resistant HIV-1 among antiretroviral therapy (ART)-naive individuals in Northern Vietnam was 2.9% in 2007 and 6.2% in 2008. To investigate the continuing trend of prevalence, we collected plasma samples from 958 individuals in Hai Phong and Hanoi in 2009, extracted viral RNA from HIV-1 antibody-positive samples, and analyzed them genetically. HIV-1 antibody prevalence was 26.8% in injecting drug users (n=302), 13.4% in female sex workers (n=284), 0.5% in blood donors (n=206), and 0.6% in pregnant women (n=166). All HIV-1 strains were CRF01_AE. Nonnucleoside reverse-transcriptase inhibitor resistance mutations were found in two (2.0%) of the 102 successfully analyzed cases (one case with the Y181C and one with the K101E). No nucleoside reverse-transcriptase inhibitor resistance or protease inhibitor resistance mutations were detected. The prevalence of circulating ART-resistant HIV-1 in Northern Vietnam did not increase from 2007 to 2009, although the rate of ART coverage did increase.