The Impact of Transmitted Drug-Resistance on Treatment Selection and Outcome of First-Line Highly Active Antiretroviral Therapy (HAART)

HIV-1 transmitted drug resistance in newly diagnosed individuals in Italy over the period 2015-21

BACKGROUND

Transmitted drug resistance (TDR) is still a critical aspect for the management of individuals living with HIV-1. Thus, its evaluation is crucial to optimize HIV care.

METHODS

Overall, 2386 HIV-1 protease/reverse transcriptase and 1831 integrase sequences from drug-naïve individuals diagnosed in north and central Italy between 2015 and 2021 were analysed. TDR was evaluated over time. Phylogeny was generated by maximum likelihood. Factors associated with TDR were evaluated by logistic regression.

RESULTS

Individuals were mainly male (79.1%) and Italian (56.2%), with a median (IQR) age of 38 (30-48). Non-B infected individuals accounted for 44.6% (N = 1065) of the overall population and increased over time (2015-2021, from 42.1% to 51.0%, P = 0.002). TDR prevalence to any class was 8.0% (B subtype 9.5% versus non-B subtypes 6.1%, P = 0.002) and remained almost constant over time. Overall, 300 transmission clusters (TCs) involving 1155 (48.4%) individuals were identified, with a similar proportion in B and non-infected individuals (49.7% versus 46.8%, P = 0.148). A similar prevalence of TDR among individuals in TCs and those out of TCs was found (8.2% versus 7.8%, P = 0.707).By multivariable analysis, subtypes A, F, and CFR02_AG were negatively associated with TDR. No other factors, including being part of TCs, were significantly associated with TDR.

CONCLUSIONS

Between 2015 and 2021, TDR prevalence in Italy was 8% and remained almost stable over time. Resistant strains were found circulating regardless of being in TCs, but less likely in non-B subtypes. These results highlight the importance of a continuous surveillance of newly diagnosed individuals for evidence of TDR to inform clinical practice.

Transmitted Drug Resistance in Antiretroviral Therapy-Naive Persons With Acute/Early/Primary HIV Infection: A Systematic Review and Meta-Analysis

Background: The widespread use of antiretroviral therapy (ART) has raised concerns about the emergence of HIV transmitted drug resistance (TDR). Acute HIV infection (AHI) was the most appropriate time to detect the spread of TDR. In this meta-analysis, our purpose was to evaluate the level of TDR in ART-naive patients with primary HIV infection (PHI)/AHI/early HIV infection (EHI) and to describe the critical drug-resistant mutations.

Methods: We systematically searched the literature between January 1, 2008, and April 30, 2021, in PubMed, Web of Science, Embase, and the Cochrane Library. To evaluate the overall prevalence of TDR, we extracted raw data and analyzed prevalence estimates using Stata SE.

Results: The data of this meta-analysis come from 12 observational studies, covering 3,558 ART-naive individuals with PHI, AHI, or EHI. The overall prevalence of HIV-TDR is 9.3% (95% CI: 6.8%–11.8%, I² = 81.1%, in 11 studies). The prevalence of resistance by drug class is the highest for the nonnucleoside reverse transcriptase inhibitors (NNRTIs) at 5.7% (95% CI: 2.9%–8.5%, I² = 96.6%, in 11 studies), followed by nucleoside reverse transcriptase inhibitors (NRTIs) at 3.4% (95% CI: 1.8%–5.0%, I² = 86.3%, in 10 studies) and protease inhibitors (PIs) at 3.3% (95% CI: 2.7%–3.9%, I² = 15.6%, in 10 studies). The prevalence of TDR to integrase inhibitors (INIs) is 0.3% (95% CI: 0.1%–0.7%, I² = 95.9%, in three studies), which is the lowest among all antiretroviral drugs.

Conclusion: The overall prevalence of TDR is at a moderate level among AHI patients who have never received ART. This emphasizes the importance of baseline drug resistance testing for public health surveillance and guiding the choice of ART. In addition, the prevalence of TDR to NNRTIs is the highest, while the TDR to INIs is the lowest. This may guide the selection of clinical antiretroviral drugs.

Clinical Impact of Pretreatment Human Immunodeficiency Virus Drug Resistance in People Initiating Nonnucleoside Reverse Transcriptase Inhibitor-Containing Antiretroviral Therapy: A Systematic Review and Meta-analysis

BACKGROUND

Increased access to antiretroviral therapy (ART) has resulted in rising levels of pretreatment human immunodeficiency virus drug resistance (PDR). This is the first systematic review and meta-analysis to assess the impact of PDR on treatment outcomes among people initiating nonnucleoside reverse transcriptase inhibitor (NNRTI)-based ART, including the combination of efavirenz (EFV), tenofovir (TDF), and lamivudine or emtricitabine (XTC).

METHODS

We systematically reviewed studies and conference proceedings comparing treatment outcomes in populations initiating NNRTI-based ART with and without PDR. We conducted subgroup analyses by regimen: (1) NNRTIs + 2 nucleoside reverse transcriptase inhibitors (NRTIs), (2) EFV + 2 NRTIs, or (3) EFV/TDF/XTC; by population (children vs adults); and by definition of resistance (PDR vs NNRTI PDR).

RESULTS

Among 6197 studies screened, 32 were analyzed (31 441 patients). We found that individuals with PDR initiating NNRTIs across all the subgroups had increased risk of virological failure compared to those without PDR. Risk of acquisition of new resistance mutations and ART switch was also higher in people with PDR.

CONCLUSIONS

This review shows poorer treatment outcomes in the presence of PDR, supporting the World Health Organization's recommendation to avoid using NNRTIs in countries where levels of PDR are high.

Predictors of virological failure and time to viral suppression of first line integrase inhibitor based antiretroviral treatment

Background

Integrase strand transfer inhibitors (InSTIs) are recommended for first-line treatment of persons with human immunodeficiency virus (HIV). We identified risk factors, including baseline minor InSTI resistance mutations, for treatment failure of InSTI-based regimens.

Methods

We studied time-to-treatment failure and time to viral suppression among 1419 drug-naive patients in the Swiss HIV Cohort Study. We performed Cox regression models adjusted for demographic factors, baseline HIV RNA/CD4 cell counts, AIDS-defining events, and the type of InSTI. In 646 patients with a baseline genotypic resistance test of the integrase, we studied the impact of minor integrase resistance mutations.

Results

We observed 121 virological failures during 18 447 person-years of follow-up. A baseline viral load ≥100 000 copies/mL (multivariable hazard ratio [mHR], 2.2; 95% confidence interval [CI], 1.3–3.6) and an AIDS-defining event (mHR, 1.8; 95% CI. 1.1–3.0) were associated with treatment failure. CD4 counts between 200 and 500 cells/µL (mHR, 0.5; 95% CI, .3–.8) and >500 cells/µL (mHR, 0.4; 95% CI, .2–.7) were protective. Time to suppression was shorter in lower viral load strata (mHR, 0.7; 95% CI, .6–.8) and in dolutegravir-based therapy (mHR, 1.2; 95% CI, 1.0–1.4). Minor resistance mutations were found at baseline in 104 of 646 (16%) patients with no effect on treatment outcome.

Conclusions

Factors associated with treatment failure on InSTI-based first-line regimen remained similar to those of older treatments, in particular high viral load and low CD4 counts.

Genetic transmission networks of HIV-1 CRF07_BC strain among HIV-1 infections with virologic failure of ART in a minority area of China: a population-based study

Background

The drug resistance and the virologic failure of antiretroviral therapy (ART) are quite severe in Liangshan. A better understanding of the virologic failure of ART and the HIV-1 transmission network dynamics is essential for the surveillance and prevention of HIV. Here, we analyzed the HIV-1 CRF07_BC strain genetic transmission networks and their associated factors among people living with HIV-1 (PLWH) who had virologic failure of ART by using close genetic links.

Methods

The drug-resistant mutations were determined using the Stanford University HIV Drug Resistance Database. HIV-1 pol genes sequences were used for phylogenetic and genotypic drug resistance analysis. The genetic transmission networks were performed by comparing sequences, constructing the phylogenetic tree, calculating the pairwise distance, and visualizing the network.

Results

A total of 1050 PLWH with CRF07_BC pol sequences were finally identified and included in the genetic transmission network analysis from 2016 to 2017. Of the 1050 CRF07_BC pol sequences, 346 (32.95%) fell into clusters at a genetic distance of 0.006, resulting in 137 clusters ranging in size from 2 to 40 individuals. Subjects who were widowed or divorced were less likely to form a genetic transmission network (adjusted OR: 0.50), while subjects who had shared a needle ≥ five times were more likely to form a network (adjusted OR: 1.88).

Conclusions

The genetic transmission networks revealed the complex transmission pattern, highlighting the urgent need for transmission monitoring of virologic failure of ART and selection of more effective therapeutic regimens to promote viral suppression.

The urgent need for more potent antiretroviral therapy in low-income countries to achieve UNAIDS 90-90-90 and complete eradication of AIDS by 2030

Background

Over 90% of Human Immunodeficiency Virus (HIV) infected individuals will be on treatment by 2020 under UNAIDS 90–90-90 global targets. Under World Health Organisation (WHO) “Treat All” approach, this number will be approximately 36.4 million people with over 98% in low-income countries (LICs).

Main body

Pretreatment drug resistance (PDR) largely driven by frequently use of non-nucleoside reverse transcriptase inhibitors (NNRTIs), efavirenz and nevirapine, has been increasing with roll-out of combined antiretroviral therapy (cART) with 29% annual increase in some LICs countries. PDR has exceeded 10% in most LICs which warrants change of first line regimen to more robust classes under WHO recommendations. If no change in regimens is enforced in LICs, it’s estimated that over 16% of total deaths, 9% of new infections, and 8% of total cART costs will be contributed by HIV drug resistance by 2030. Less than optimal adherence, and adverse side effects associated with currently available drug regimens, all pose a great threat to achievement of 90% viral suppression and elimination of AIDS as a public health threat by 2030. This calls for urgent introduction of policies that advocate for voluntary and compulsory drug licensing of new more potent drugs which should also emphasize universal access of these drugs to all individuals worldwide.

Conclusions

The achievement of United Nations Programme on HIV and AIDS 2020 and 2030 targets in LICs depends on access to active cART with higher genetic barrier to drug resistance, better safety, and tolerability profiles. It’s also imperative to strengthen quality service delivery in terms of retention of patients to treatment, support for adherence to cART, patient follow up and adequate drug stocks to help achieve a free AIDS generation.

Electronic supplementary material

The online version of this article (10.1186/s40249-019-0573-1) contains supplementary material, which is available to authorized users.

Pretreatment HIV drug resistance results in virological failure and accumulation of additional resistance mutations in Ugandan children

Background

Pretreatment HIV drug resistance (PDR) can impair virological response to ART, jeopardizing effective treatment for children.

Methods

Children aged ≤12 years initiated first-line ART in Uganda during 2010-11. Baseline and 6 monthly viral load (VL) and genotypic resistance testing if VL >1000 copies/mL was done. The 2015 IAS-USA mutation list and Stanford algorithm were used to score drug resistance mutations (DRMs) and susceptibility. Virological failure (VF) was defined as two consecutive VLs >1000 copies/mL or death after 6 months of ART. Factors associated with failure and acquired drug resistance (ADR) were assessed in a logistic regression analysis.

Results

Among 317 children enrolled, median age was 4.9 years and 91.5% received NNRTI-based regimens. PDR was detected in 47/278 (16.9%) children, of whom 22 (7.9%) had resistance against their first-line regimen and were therefore on a partially active regimen. After 24 months of follow-up, 92/287 (32.1%) had experienced VF. Children with PDR had a higher risk of VF (OR 15.25, P < 0.001) and ADR (OR 3.58, P = 0.01).

Conclusions

Almost one-third of children experienced VF within 24 months of NNRTI-based first-line treatment. PDR was the strongest predictor of VF and ADR, and therefore presents a major threat in children. There is a need for ART regimens that maximize effectiveness of first-line therapy for long-term treatment success in the presence of PDR or incorporation of routine VL testing to detect VF and change treatment in time, in order to prevent clinical deterioration and accumulation of additional drug resistance. Children ≤3 years should be initiated on a PI-based regimen as per WHO guidelines.

High Levels of Transmitted HIV Drug Resistance in a Study in Papua New Guinea

INTRODUCTION

Papua New Guinea is a Pacific Island nation of 7.3 million people with an estimated HIV prevalence of 0.8%. ART initiation and monitoring are guided by clinical staging and CD4 cell counts, when available. Little is known about levels of transmitted HIV drug resistance in recently infected individuals in Papua New Guinea.

METHODS

Surveillance of transmitted HIV drug resistance in a total of 123 individuals recently infected with HIV and aged less than 30 years was implemented in Port Moresby (n = 62) and Mount Hagen (n = 61) during the period May 2013-April 2014. HIV drug resistance testing was performed using dried blood spots. Transmitted HIV drug resistance was defined by the presence of one or more drug resistance mutations as defined by the World Health Organization surveillance drug resistance mutations list.

RESULTS

The prevalence of non-nucleoside reverse transcriptase inhibitor transmitted HIV drug resistance was 16.1% (95% CI 8.8%-27.4%) and 8.2% (95% CI 3.2%-18.2%) in Port Moresby and Mount Hagen, respectively. The prevalence of nucleoside reverse transcriptase inhibitor transmitted HIV drug resistance was 3.2% (95% CI 0.2%-11.7%) and 3.3% (95% CI 0.2%-11.8%) in Port Moresby and Mount Hagen, respectively. No protease inhibitor transmitted HIV drug resistance was observed.

CONCLUSIONS

The level of non-nucleoside reverse transcriptase inhibitor drug resistance in antiretroviral drug naïve individuals recently infected with HIV in Port Moresby is amongst the highest reported globally. This alarming level of transmitted HIV drug resistance in a young sexually active population threatens to limit the on-going effective use of NNRTIs as a component of first-line ART in Papua New Guinea. To support the choice of nationally recommended first-line antiretroviral therapy, representative surveillance of HIV drug resistance among antiretroviral therapy initiators in Papua New Guinea should be urgently implemented.

Pretreatment HIV-1 drug resistance in Argentina: results from a surveillance study performed according to WHO-proposed new methodology in 2014-15

BACKGROUND

In Argentina, current national guidelines recommend starting with NNRTI-based regimens. Recently, there have been some local reports regarding concerning levels of NNRTI-transmitted resistance, but surveillance has never been carried out at a national level.

OBJECTIVES

To determine the prevalence of HIV drug resistance in people starting ART in Argentina using a WHO-proposed methodology.

METHODS

This was a cross-sectional, nationally representative study. Twenty-five antiretroviral-dispensing sites throughout the country were randomly chosen to enrol at least 330 persons starting ART, to generate a point prevalence estimate of resistance-associated mutations (RAMs) with a 5% CI (for the total population and for those without antiretroviral exposure). All consecutive patients older than 18 years starting or restarting ART in the chosen clinics were eligible. Samples were processed with Trugene and analysed using the Stanford algorithm.

RESULTS

Between August 2014 and March 2015, we obtained 330 samples from people starting ART. The mean ± SD age was 35 ± 11 years, 63.4% were male, 16.6% had prior antiretroviral exposure and the median (IQR) CD4 count was 275 cells/mm³ (106-461). The prevalence of RAMs found was 14% (±4%) for the whole population (3% NRTI-RAMs; 11% NNRTI-RAMs and 2% PI-RAMs) and 13% (±4%) for those without prior antiretroviral exposure (3%, 10% and 2%, respectively). The most common mutation was K103N.

CONCLUSIONS

This surveillance study showed concerning levels of HIV drug resistance in Argentina, especially to NNRTIs. Due to this finding, Argentina's Ministry of Health guidelines will change, recommending performing a resistance test for everyone before starting ART. If this is taken up properly, it also might function as a continuing surveillance tool.

Prevalence of Primary HIV Drug Resistance in Thailand Detected by Short Reverse Transcriptase Genotypic Resistance Assay

BACKGROUND

HIV drug resistance (HIVDR) is the major cause of treatment failure after scaling up of antiretroviral therapy (ART). HIVDR testing prior to ART initiation is not routinely performed in resource-limited settings. We aimed to assess the prevalence of primary HIVDR by short reverse transcriptase (RT) genotypic resistance assay and evaluate of the impact of the mutations on the treatment outcomes.

METHODS

A prospective cohort study was conducted in treatment-naïve HIV-infected patients. Fourteen major mutations of codon 99-191 on the RT gene were selected (K103N, V106A/M, V108I, Q151M, Y181C/I, M184V/I, Y188C/L/H, and G190S/A) at a cost of testing of 35 USD. The association between the presence of primary HIVDR and undetectable HIV RNA (<50 copies/mL) after 6 months of ART was determined.

RESULTS

A total of 265 HIV-infected patients were included, with a median age of 35.2 (range, 16.8-75.2) years; 62.6% were males. The median (interquartile range) CD4 cell count at ART initiation was 216 (77-381) cells/mm3. The overall prevalence of primary HIVDR was 7.9%. The prevalence of each HIVDR mutation were K103N 6.0%, V106I 1.1%, V108I 0.4%, Y181C 2.3%, Y181I 0.7%, Y181V 0.4%, M184V 3.0%, M184I 1.5%, and G190A 2.3%. No associated factor of having primary HIVDR was determined. By multiple stepwise logistic regression, factors associated with undetectable HIV RNA after 6 months of ART were: having M184V/I (odds ratio [OR] 0.11; 95% confidence interval [CI] 0.02-0.62, p = 0.013), condom use (OR 2.38; 95% CI 1.12-5.06, p = 0.024), and adherence per 5% increase (OR 1.16; 95% CI 1.00-1.35, p = 0.044).

CONCLUSIONS

The prevalence of primary HIVDR is approximately 8%; it is associated with detectable HIV RNA at 6 months after ART initiation. Routine "short RT" genotypic resistance assay should be considered in resource-limited settings to maximize treatment outcome.

Primer ID Informs Next-Generation Sequencing Platforms and Reveals Preexisting Drug Resistance Mutations in the HIV-1 Reverse Transcriptase Coding Domain

Sequencing of a bulk polymerase chain reaction (PCR) product to identify drug resistance mutations informs antiretroviral therapy selection but has limited sensitivity for minority variants. Alternatively, deep sequencing is capable of detecting minority variants but is subject to sequencing errors and PCR resampling due to low input templates. We screened for resistance mutations among 184 HIV-1-infected, therapy-naive subjects using the 454 sequencing platform to sequence two amplicons spanning HIV-1 reverse transcriptase codons 34-245. Samples from 19 subjects were also analyzed using the MiSeq sequencing platform for comparison. Errors and PCR resampling were addressed by tagging each HIV-1 RNA template copy (i.e., cDNA) with a unique sequence tag (Primer ID), allowing a consensus sequence to be constructed for each original template from resampled sequences. In control reactions, Primer ID reduced 454 and MiSeq errors from 71 to 2.6 and from 24 to 1.2 errors/10,000 nucleotides, respectively. MiSeq also allowed accurate sequencing of codon 65, an important drug resistance position embedded in a homopolymeric run that is poorly resolved by the 454 platform. Excluding homopolymeric positions, 14% of subjects had evidence of ≥1 resistance mutation among Primer ID consensus sequences, compared to 2.7% by bulk population sequencing. When calls were restricted to mutations that appeared twice among consensus sequence populations, 6% of subjects had detectable resistance mutations. The use of Primer ID revealed 5-15% template utilization on average, limiting the depth of deep sequencing sampling and revealing sampling variation due to low template utilization. Primer ID addresses important limitations of deep sequencing and produces less biased estimates of low-level resistance mutations in the viral population.

Pretreatment HIV Drug Resistance and HIV-1 Subtype C Are Independently Associated With Virologic Failure: Results From the Multinational PEARLS (ACTG A5175) Clinical Trial

BACKGROUND

Evaluation of pretreatment HIV genotyping is needed globally to guide treatment programs. We examined the association of pretreatment (baseline) drug resistance and subtype with virologic failure in a multinational, randomized clinical trial that evaluated 3 antiretroviral treatment (ART) regimens and included resource-limited setting sites.

METHODS

Pol genotyping was performed in a nested case-cohort study including 270 randomly sampled participants (subcohort), and 218 additional participants failing ART (case group). Failure was defined as confirmed viral load (VL) >1000 copies/mL. Cox proportional hazards models estimated resistance-failure association.

RESULTS

In the representative subcohort (261/270 participants with genotypes; 44% women; median age, 35 years; median CD4 cell count, 151 cells/µL; median VL, 5.0 log10 copies/mL; 58% non-B subtypes), baseline resistance occurred in 4.2%, evenly distributed among treatment arms and subtypes. In the subcohort and case groups combined (466/488 participants with genotypes), used to examine the association between resistance and treatment failure, baseline resistance occurred in 7.1% (9.4% with failure, 4.3% without). Baseline resistance was significantly associated with shorter time to virologic failure (hazard ratio [HR], 2.03; P = .035), and after adjusting for sex, treatment arm, sex-treatment arm interaction, pretreatment CD4 cell count, baseline VL, and subtype, was still independently associated (HR, 2.1; P = .05). Compared with subtype B, subtype C infection was associated with higher failure risk (HR, 1.57; 95% confidence interval [CI], 1.04-2.35), whereas non-B/C subtype infection was associated with longer time to failure (HR, 0.47; 95% CI, .22-.98).

CONCLUSIONS

In this global clinical trial, pretreatment resistance and HIV-1 subtype were independently associated with virologic failure. Pretreatment genotyping should be considered whenever feasible.

CLINICAL TRIALS REGISTRATION

NCT00084136.

Transmitted antiretroviral drug resistance in the men who have sex with men HIV patient cohort, Beijing, China, 2008-2011

Transmitted drug resistance (TDR) is an ongoing public health problem in HIV disease treatment. However, little is known about TDR among men who have sex with men (MSM) patients in China. In addition, TDR prevalence among patients with acute HIV infection (AHI) or early HIV infection (EHI) was believed higher than that of patients with chronic HIV infection (CHI), but as AHI is typically either unidentified or crudely defined in large populations, very few direct comparisons have been made. We did a retrospective analysis of TDR in 536 antiretroviral-naive MSM patients from our immunodeficiency clinics at You'an Hospital, Capital Medical University (CMU), in Beijing, China, 2008-2011. The cohort included 266 patients with AHI/EHI and 270 patients with CHI. We analyzed the subtype, estimated the TDR prevalence, and characterized the model of TDR and the predicted drug sensitivity. Additionally, we made a comparison of TDR between the patients with AHI/EHI and patients with CHI. Our results indicated that among the 536 patients, HIV-1 subtype CRF01_AE accounted for 52.1%, subtype B accounted for 24.8%, CRF07_BC/ CRF08_BC accounted for 21.6% (116/536), and 1.3% were denoted as unique recombinant forms (URFs). A total of 7.8% patients had one or more transmitted HIV-1 drug resistance mutations, representing 6.2% for PI-related mutations, 0.9% for NRTI-related mutations, and 1.7% for NNRTI-related mutations. Although patients with AHI/EHI had a higher TDR prevalence as compared to that of patients with CHI, the difference was not statistically significant. There was no significant difference in TDR model and predicted drug susceptibility between the two groups of patients either. This study provides important strategic information for public health planning by healthcare officials in China and warrants a comprehensive study with larger patient cohorts from various healthcare centers within China.

First line treatment response in patients with transmitted HIV drug resistance and well defined time point of HIV infection: updated results from the German HIV-1 seroconverter study

Background

Transmission of drug-resistant HIV-1 (TDR) can impair the virologic response to antiretroviral combination therapy. Aim of the study was to assess the impact of TDR on treatment success of resistance test-guided first-line therapy in the German HIV-1 Seroconverter Cohort for patients infected with HIV between 1996 and 2010. An update of the prevalence of TDR and trend over time was performed.

Methods

Data of 1,667 HIV-infected individuals who seroconverted between 1996 and 2010 were analysed. The WHO drug resistance mutations list was used to identify resistance-associated HIV mutations in drug-naïve patients for epidemiological analysis. For treatment success analysis the Stanford algorithm was used to classify a subset of 323 drug-naïve genotyped patients who received a first-line cART into three resistance groups: patients without TDR, patients with TDR and fully active cART and patients with TDR and non-fully active cART. The frequency of virologic failure 5 to 12 months after treatment initiation was determined.

Results

Prevalence of TDR was stable at a high mean level of 11.9% (198/1,667) in the HIV-1 Seroconverter Cohort without significant trend over time. Nucleotide reverse transcriptase inhibitor resistance was predominant (6.0%) and decreased significantly over time (OR = 0.92, CI = 0.87–0.98, p = 0.01). Non-nucleoside reverse transcriptase inhibitor (2.4%; OR = 1.00, CI = 0.92–1.09, p = 0.96) and protease inhibitor resistance (2.0%; OR = 0.94, CI = 0.861.03, p = 0.17) remained stable. Virologic failure was observed in 6.5% of patients with TDR receiving fully active cART, 5,6% of patients with TDR receiving non-fully active cART and 3.2% of patients without TDR. The difference between the three groups was not significant (p = 0.41).

Conclusion

Overall prevalence of TDR remained stable at a rather high level. No significant differences in the frequency of virologic failure were identified during first-line cART between patients with TDR and fully-active cART, patients with TDR and non-fully active cART and patients without TDR.

Surveillance of transmitted HIV drug resistance in antiretroviral-naive patients aged less than 25 years, in Bangkok, Thailand

Emergence of transmitted HIV drug resistance (TDR) is a concern after global scale-up of antiretroviral therapy (ART). World Health Organization had developed threshold survey method for surveillance of TDR in resource-limited countries. ART in Thailand has been scaling up for >10 years. To evaluate the current TDR in Thailand, a cross-sectional study was conducted among antiretroviral-naive HIV-infected patients aged <25 years who newly visited infectious disease clinic in a university hospital, in 2011. HIV genotypic-resistance test was performed. World Health Organization 2009 surveillance drug-resistance mutations were used to define TDR. Of 50 patients, the prevalence of TDR was 4%. Of 2 patients with TDR, 1 had K103N and the other had Y181C mutations. Transmitted HIV drug resistance is emerging in Thailand after a decade of rapid scale-up of ART. Interventions to prevent TDR at the population level are essentially needed in Thailand. Surveillance for TDR in Thailand has to be regularly performed.

Prevalence of drug-resistant HIV type 1 at the time of initiation of antiretroviral therapy in Portland, Oregon

The presence of transmitted drug-resistant HIV-1 (TDR) at the time of antiretroviral therapy (ART) initiation is associated with failure to achieve viral load suppression. Rates of TDR in ART-naive patients have been reported from various parts of the world through ongoing national, regional, and global evaluations; however, surveillance of TDR in Portland, Oregon has not been previously described. We describe the prevalence of TDR in patients in the Portland area who have recently entered care. Genotypic data were obtained from plasma specimens collected between 2003 and 2009 from 165 recently identified HIV-1-positive, ART-naive adults in care at the Multnomah County Health Department. Median time from diagnosis to first genotype was 2.7 months. Mutations associated with TDR were observed in 33 (20.0%) patients. Mutations associated with resistance to nucleoside reverse transcriptase (RT) inhibitors (NRTI), nonnucleoside RT inhibitors (NNRTI), and protease inhibitors (PI) were found in 15 (9.1%), 17 (10.3%), and 5 (3.0%) patients, respectively (p=0.013 for NNRTI vs. PI, and 0.035 for NRTI vs. PI, Fisher exact test). Dual class resistance was observed in four (2.4%) patients. Predominant RT mutations included M41L, T215C or S, and K103N. The prevalence of HIV-1 with NRTI resistance-associated mutations increased from 2006 to 2008-2009 (p=0.004) based on date of diagnosis. These data indicate relatively high rates of drug resistance present prior to ART initiation among patients in the Portland area, and support continued surveillance of local trends of TDR to inform optimal individual treatment strategies and public health decisions.

Transmitted drug resistance and phylogenetic relationships among acute and early HIV-1-infected individuals in New York City

BACKGROUND

Transmitted drug resistance (TDR) is critical to managing HIV-1-infected individuals and being a public health concern. We report on TDR prevalence and include analyses of phylogenetic clustering of HIV-1 in a predominantly men who have sex with men cohort diagnosed during acute/recent HIV-1 infection in New York City.

METHODS

Genotypic resistance testing was conducted on plasma samples of 600 individuals with acute/recent HIV-1 infection (1995-2010). Sequences were used for resistance and phylogenetic analyses. Demographic and clinical data were abstracted from medical records. TDR was defined according to International AIDS Society-USA and Stanford HIV database guidelines. Phylogenetic and other analyses were conducted using PAUP*4.0 and SAS, respectively.

RESULTS

The mean duration since HIV-1 infection was 66.5 days. TDR prevalence was 14.3% and stably ranged between 10.8% and 21.6% (P(trend) = 0.42). Nucleoside reverse transcriptase inhibitors resistance declined from 15.5% to 2.7% over the study period (P(trend) = 0.005). M41L (3.7%), T215Y (4.0%), and K103N/S (4.7%) were the most common mutations. K103N/S prevalence increased from 1.9% to 8.0% between 1995 and 2010 (P(trend) = 0.04). Using a rigorous definition of clustering, 19.3% (112 of 581) of subtype B viral sequences cosegregated into transmission clusters and clusters increased over time. There were fewer and smaller transmission clusters than had been reported in a similar cohort in Montreal but similar to reports from elsewhere.

CONCLUSIONS

TDR is stable in this cohort and remains a significant concern to both individual patient management and the public health.

Emergence of HIV-1 drug resistance mutations among antiretroviral-naïve HIV-1-infected patients after rapid scaling up of antiretroviral therapy in Thailand

Background

After rapid scaling up of antiretroviral therapy in HIV-1-infected patients, the data of primary HIV-1 drug resistance in Thailand is still limited. This study aims to determine the prevalence and associated factors of primary HIV-1 drug resistance in Thailand.

Methods

A prospective observational study was conducted among antiretroviral-naïve HIV-1-infected Thai patients from 2007 to 2010. HIV-1 subtypes and mutations were assayed by sequencing a region of HIV-1 pol gene. Surveillance drug resistance mutations recommended by the World Health Organization for surveillance of transmitted HIV-1 drug resistance in 2009 were used in all analyses. Primary HIV-1 drug resistance was defined as the presence of one or more surveillance drug resistance mutations.

Results

Of 466 patients with a mean age of 38.8 years, 58.6% were males. Risks of HIV-1 infection included heterosexual (77.7%), homosexual (16.7%), and intravenous drug use (5.6%). Median (IQR) CD4 cell count and HIV-1 RNA were 176 (42-317) cells/mm³ and 68,600 (19,515-220,330) copies/mL, respectively. HIV-1 subtypes were CRF01_AE (86.9%), B (8.6) and other recombinants (4.5%). The prevalence of primary HIV-1 drug resistance was 4.9%; most of these (73.9%) had surveillance drug resistance mutations to only one class of antiretroviral drugs. The prevalence of patients with NRTI, NNRTI, and PI surveillance drug resistance mutations was 1.9%, 2.8% and 1.7%, respectively. From logistic regression analysis, there was no factor significantly associated with primary HIV-1 drug resistance. There was a trend toward higher prevalence in females [odds ratio 2.18; 95% confidence interval 0.896-5.304; p = 0.086].

Conclusions

There is a significant emergence of primary HIV-1 drug resistance in Thailand after rapid scaling up of antiretroviral therapy. Although HIV-1 genotyping prior to antiretroviral therapy initiation is not routinely recommended in Thailand, our results raise concerns about the risk of early treatment failure in patients with primary HIV-1 drug resistance. Interventions to prevent the transmission of HIV-1 drug resistance and continuation of surveillance for primary HIV-1 drug resistance in Thailand are indicated.

Epidemiology of transmitted drug resistance in chronically HIV-infected patients in Germany: the RESINA study 2001-2009

OBJECTIVES

Transmitted HIV drug resistance may impair treatment efficacy of combination antiretroviral therapy (ART). This study describes the epidemiology of transmitted resistance in chronically infected patients.

METHODS

In a prospective multicenter trial in Nordrhein-Westfalen, Germany, transmitted drug resistance was determined by genotypic resistance testing in patients on initiation of first-line ART.

RESULTS

From 2001 to 2009, 2,078 patients were enrolled in the study. 79.9% were male, 81.2% were Caucasians, and a homosexual transmission mode was found in 51.3%. Of these patients, 41.5% were at the stage of AIDS, median CD4 cell count was 230/μl, and median viral load was 64.466 copies/ml. Transmitted drug resistance mutations were seen in 9.2% (95% CI, 7.9-10.4). Resistance in the nucleoside reverse transcriptase inhibitor class was found in 5.8% (4.8-6.8), in the nonnucleoside reverse transcriptase inhibitor class in 2.8% (2.1-3.6), and in the protease inhibitor class in 2.7% (2.0-3.4). After a continuous increase to a level above 10% in the years 2006 and 2007, a decline of drug resistance prevalence followed in 2008 and 2009.

CONCLUSIONS

Transmitted HIV drug resistance was found in around 10% of chronically infected patients in Germany who started their ART. We showed a moderate decline of the prevalence of mutant virus strains in recent years. Further surveillance of this phenomenon is mandatory.

Effect of pretreatment HIV-1 drug resistance on immunological, virological, and drug-resistance outcomes of first-line antiretroviral treatment in sub-Saharan Africa: a multicentre cohort study

BACKGROUND

The effect of pretreatment HIV-1 drug resistance on the response to first-line combination antiretroviral therapy (ART) in sub-Saharan Africa has not been assessed. We studied pretreatment drug resistance and virological, immunological, and drug-resistance treatment outcomes in a large prospective cohort.

METHODS

HIV-1 infected patients in the PharmAccess African Studies to Evaluate Resistance Monitoring (PASER-M) cohort started non-nucleoside reverse transcriptase inhibitor-based ART at 13 clinical sites in six countries, from 2007 to 2009. We used the International Antiviral Society-USA drug resistance mutation list and the Stanford algorithm to classify participants into three pretreatment drug resistance categories: no pretreatment drug resistance, pretreatment drug resistance with fully active ART prescribed, or pretreatment drug resistance with reduced susceptibility to at least one prescribed drug. We assessed risk factors of virological failure (≥400 copies per mL) and acquired drug resistance after 12 months of ART by use of multilevel logistic regression with multiple imputations for missing data. CD4 cell count increase was estimated with linear mixed models.

FINDINGS

Pretreatment drug resistance results were available for 2579 (94%) of 2733 participants; 2404 (93%) had no pretreatment drug resistance, 123 (5%) had pretreatment drug resistance to at least one prescribed drug, and 52 (2%) had pretreatment drug resistance and received fully active ART. Compared with participants without pretreatment drug resistance, the odds ratio (OR) for virological failure (OR 2·13, 95% CI 1·44-3·14; p<0·0001) and acquired drug-resistance (2·30, 1·55-3·40; p<0·0001) was increased in participants with pretreatment drug resistance to at least one prescribed drug, but not in those with pretreatment drug resistance and fully active ART. CD4 count increased less in participants with pretreatment drug resistance than in those without (35 cells per μL difference after 12 months; 95% CI 13-58; p=0·002).

INTERPRETATION

At least three fully active antiretroviral drugs are needed to ensure an optimum response to first-line regimens and to prevent acquisition of drug resistance. Improved access to alternative combinations of antiretroviral drugs in sub-Saharan Africa is warranted.

FUNDING

The Netherlands Ministry of Foreign Affairs.

Postpartum viral load rebound in HIV-1-infected women treated with highly active antiretroviral therapy: AIDS Clinical Trials Group Protocol A5150

BACKGROUND

Pregnancy may lead to increases in HIV-1 RNA levels postpartum. The AIDS Clinical Trials Group (ACTG) A5150 study was designed to characterize the incidence of viral load rebound during the immediate 24 weeks postpartum and explore factors associated with viral load rebound.

METHODS

We enrolled pregnant women in the United States who were ≥13 years of age, between 22 to 30 weeks gestation, and who planned to be on stable highly active antiretroviral therapy (HAART) for ≥8 weeks predelivery and to continue this therapy after delivery for the duration of the study. Choice of antiretrovirals (ARVs) was determined by the primary HIV provider. Viral load rebound was defined as an increase of ≥0.7 log10 (5-fold) from the average of the weeks 34 and 36 gestation viral loads to week 24 postpartum or an absolute increase to ≯500 copies/mL for those with viral load <50 copies/mL.

RESULTS

Eighty-four women enrolled for postpartum follow-up. Sixty-three had follow-up and viral load obtained through week 24 postpartum. Overall, 18/63 (28.6%; 95% confidence interval [CI], 17.9-41.4) met criteria for viral load rebound. Nineteen of the 63 women made changes or discontinued their ARV regimen prior to week 24 postpartum. For those who remained on stable ARVs, rebound occurred in 8/44 (18.2%; 95% CI, 8.2-32.7) compared with 10/19 (52.6%; 95% CI, 28.9-75.5) who did not remain on a stable ARV regimen.

CONCLUSIONS

In the early postpartum period, HIV-1-infected women commonly have increases in viral load. Unplanned changes in ARV regimens and discontinuations of treatment are frequent.