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

Pre-treatment minority HIV-1 drug resistance mutations and long term virological outcomes: is prediction possible?

Background

Although the use of highly active antiretroviral therapy in HIV positive individuals has proved to be effective in suppressing the virus to below detection limits of commonly used assays, virological failure associated with drug resistance is still a major challenge in some settings. The prevalence and effect of pre-treatment resistance associated variants on virological outcomes may also be underestimated because of reliance on conventional population sequencing data which excludes minority species. We investigated long term virological outcomes and the prevalence and pattern of pre-treatment minority drug resistance mutations in individuals initiating HAART at a local HIV clinic.

Methods

Patient’s records of viral load results and CD4 cell counts from routine treatment monitoring were used and additional pre-treatment blood samples for Sanger sequencing were obtained. A selection of pre-treatment samples from individuals who experienced virological failure were evaluated for minority resistance associated mutations to 1 % prevalence and compared to individuals who achieved viral suppression.

Results

At least one viral load result after 6 months or more of treatment was available for 65 out of 78 individuals followed for up to 33 months. Twenty (30.8 %) of the 65 individuals had detectable viremia and eight (12.3 %) of them had virological failure (viral load > 1000 RNA copies/ml) after at least 6 months of HAART. Viral suppression, achieved by month 8 to month 13, was followed by low level viremia in 10.8 % of patients and virological failure in one patient after month 20. There was potentially reduced activity to Emtricitabine or Tenofovir in three out of the eight cases in which minority drug resistance associated variants were investigated but detectable viremia occurred in one of these cases while the activity of Efavirenz was generally reduced in all the eight cases.

Conclusions

Early viral suppression was followed by low level viremia for some patients which may be an indication of failure to sustain viral suppression over time. The low level viremia may also be representing early stages of resistance development. The mutation patterns detected in the minority variants showed potential reduced drug sensitivity which highlights their potential to dominate after treatment initiation.

Trial registration

Not applicable.

Electronic supplementary material

The online version of this article (doi:10.1186/s12985-016-0628-x) contains supplementary material, which is available to authorized users.

Virological Response and Drug Resistance 1 and 2 Years Post-Partum in HIV-Infected Women Initiated on Life-Long Antiretroviral Therapy in Malawi

The objective of this study was to determine the virological response and the possible emergence of drug resistance at 1 and 2 years postpartum in HIV-positive pregnant women enrolled under the Option B approach and meeting the criteria for treatment. In the study, women with baseline CD4(+) <350/mm(3) received a combination of stavudine, lamivudine, and nevirapine during pregnancy (from week 25 of gestation) and continued it indefinitely after delivery. HIV-RNA was measured at 12 and 24 months postpartum. Drug resistance mutations were assessed in those with HIV-RNA >50 copies/ml. Baseline resistance mutations were assessed in the entire cohort. A total of 107 women were studied. At baseline, resistance mutations were seen in 6.6% of the women. At 12 months, 26.7% of the women had >50 copies/ml and among them 12.9% had virological failure (HIV-RNA >1,000 copies/ml). At 24 months, detectable HIV-RNA was seen in 28.3% of the women and virological failure in 10.1% of the women. Resistance mutations (mainly non-nucleoside reverse transcriptase inhibitors mutations) were seen in 40% of the women with detectable HIV-RNA. Baseline mutations did not correlate with virological failure or the emergence of resistance at later time points. Virological failure 2 years postpartum and emergence of resistance were rare in this cohort of HIV-infected women. These findings are reassuring in the light of the new strategies for the prevention of mother-to-child HIV transmission, recommending life-long antiretroviral therapy administration.

Increased replication capacity following evolution of PYxE insertion in Gag-p6 is associated with enhanced virulence in HIV-1 subtype C from East Africa

BACKGROUND

A lower virulence of HIV-1 subtype C (HIV-1C) is suggested to be related to the global dominance of HIV-1C. In this observational study, combining in vivo (clinical monitoring) and in vitro (genotypic, biochemical, and phenotypic assays), we explored whether HIV-1C from East Africa (HIV-1C_EA ) is more pathogenic due to the evolution of a PYxE-insertion (C_PYxEi ) in the gag-p6 that also could affect the therapy response.

METHODS

HIV-1B (n = 112) and HIV-1C_EA (n = 128)-infected individuals residing in Sweden were analyzed with regard to Gag-p6 genotype and clinically monitored. Based on the Gag-p6 characteristics, three HIV-1C_EA and one HIV-1 B patient-derived p2-INT-recombinant virus (gag-p2/NCp7/p1/p6/pol-PR/RT/IN) were constructed to analyze viral growth kinetics (VGKs) and drug sensitivity assays. Reverse transcriptase (RT) from the same samples was cloned into the heterodimer expression plasmid (pRT6H-PROT) to analyze catalytic efficiency of RT.

RESULTS

A higher viral failure rate and lower pre-therapy CD4⁺ T-cell counts were observed in HIV-1C_EA -infected patients compared to HIV-1B-infected patients. In Gag-p6, PTAP-duplication was more common in HIV-1C. HIV-1C_EA -infected patients with signature C_PYxEi, evidenced very low pre-therapy CD4⁺ T-cell counts and suboptimal gain in CD4⁺ T-cells following therapy, as compared to the non-C_PYxEi -strains indicating higher virulence. VGKs showed a statistically significant higher replication capacity (RC) for the C_PYxEi viruses than the other two non-C_PYxEi strains. No statistically significant difference was observed in the catalytic efficiency among HIV-1C RTs.

CONCLUSIONS

This is the first evidence of polymerase independent increased virulence and RC in HIV-1C_EA following PYxE-insertion that is associated with suboptimal CD4⁺ T-cell gain following therapy initiation. J. Med. Virol. 89:106-111, 2017. © 2016 Wiley Periodicals, Inc.

Brief Report: HIV Drug Resistance in Adults Failing Early Antiretroviral Treatment: Results From the HIV Prevention Trials Network 052 Trial

Early initiation of antiretroviral treatment (ART) reduces HIV transmission and has health benefits. HIV drug resistance can limit treatment options and compromise use of ART for HIV prevention. We evaluated drug resistance in 85 participants in the HIV Prevention Trials Network 052 trial who started ART at CD4 counts of 350-550 cells per cubic millimeter and failed ART by May 2011; 8.2% had baseline resistance and 35.3% had resistance at ART failure. High baseline viral load and less education were associated with emergence of resistance at ART failure. Resistance at ART failure was observed in 7 of 8 (87.5%) participants who started ART at lower CD4 cell counts.

Predicting resistance as indicator for need to switch from first-line antiretroviral therapy among patients with elevated viral loads: development of a risk score algorithm

Background

In resource-limited settings, where resistance testing is unavailable, confirmatory testing for patients with high viral loads (VL) delays antiretroviral therapy (ART) switches for persons with resistance. We developed a risk score algorithm to predict need for ART change by identifying resistance among persons with persistently elevated VL.

Methods

We analyzed data from a Phase IV open-label trial. Using logistic regression, we identified demographic and clinical characteristics predictive of need for ART change among participants with VLs ≥1000 copies/ml, and assigned model-derived scores to predictors. We designed three models, including only variables accessible in resource-limited settings.

Results

Among 290 participants with at least one VL ≥1000 copies/ml, 51 % (148/290) resuppressed and did not have resistance testing; among those who did not resuppress and had resistance testing, 47 % (67/142) did not have resistance and 53 % (75/142) had resistance (ART change needed for 25.9 % (75/290)). Need for ART change was directly associated with higher baseline VL and higher VL at time of elevated measure, and inversely associated with treatment duration. Other predictors included body mass index and adherence. Area under receiver operating characteristic curves ranged from 0.794 to 0.817. At a risk score ≥9, sensitivity was 14.7–28.0 % and specificity was 96.7–98.6 %.

Conclusions

Our model performed reasonably well and may be a tool to quickly transition persons in need of ART change to more effective regimens when resistance testing is unavailable. Use of this algorithm may result in public health benefits and health system savings through reduced transmissions of resistant virus and costs on laboratory investigations.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-016-1611-2) contains supplementary material, which is available to authorized users.

Extensive variation in drug-resistance mutational profile of Brazilian patients failing antiretroviral therapy in five large Brazilian cities

Background

Development of drug-resistance mutations is the main cause of failure in antiretroviral therapy. In Brazil, there is scarce information on resistance pattern for patients failing antiretroviral therapy.

Objectives

To define the HIV mutational profile associated with drug resistance in Brazilian patients from 5 large cities, after first, second or further failures to antiretroviral therapy.

Methods

We reviewed genotyping results of 1520 patients failing therapy in five Brazilian cities. Frequency of mutations, mean number of active drugs, viral susceptibility to each antiretrovirals drug, and regional differences were assessed.

Results

Mean time of antiretrovirals use was 22.7 ± 41.1 months. Mean pre-genotyping viral load was 4.2 ± 0.8 log (2.1 ± 2.0 after switching antiretrovirals). Mean number of remaining active drugs was 9.4, 9.0, and 7.9 after 1st, 2nd, and 3rd failure, respectively. We detected regional variations in drug susceptibility: while BA and RS showed the highest (∼40%) resistance level to ATV/r, FPV/r and LPV/r, in the remaining cities it was around half of this rate. We detected 90% efavirenz/nevirapine resistance in SP, only 45% in RS, and levels between 25% and 30% in the other cities. Regarding NRTI, we found a similar pattern, with RJ presenting the highest, and CE the lowest susceptibility rates for all NRTI. Zidovudine resistance was detected in only 3% of patients in RJ, against 45–65% in the other cities. RJ and RS showed 3% resistance to tenofovir, while in CE it reached 55%. DRV/r (89–97%) and etravirine (61–85%) were the most active drugs, but again, with a wide variation across cities.

Conclusions

The resistance mutational profile of Brazilian patients failing antiretroviral therapy is quite variable, depending on the city where patients were tested. This variation likely reflects distinctive choice of antiretrovirals drugs to initiate therapy, adherence to specific drugs, or circulating HIV-1 strains. Overall, etravirine and DRV/r remain as the most active drugs.

Treatment failure and drug resistance in HIV-positive patients on tenofovir-based first-line antiretroviral therapy in western Kenya

Introduction

Tenofovir-based first-line antiretroviral therapy (ART) is recommended globally. To evaluate the impact of its incorporation into the World Health Organization (WHO) guidelines, we examined treatment failure and drug resistance among a cohort of patients on tenofovir-based first-line ART at the Academic Model Providing Access to Healthcare, a large HIV treatment programme in western Kenya.

Methods

We determined viral load (VL), drug resistance and their correlates in patients on ≥six months of tenofovir-based first-line ART. Based on enrolled patients’ characteristics, we described these measures in those with (prior ART group) and without (tenofovir-only group) prior non-tenofovir-based first-line ART using Wilcoxon rank sum and Fisher's exact tests.

Results

Among 333 participants (55% female; median age 41 years; median CD4 336 cells/µL), detectable (>40 copies/mL) VL was found in 18%, and VL>1000 copies/mL (WHO threshold) in 10%. Virologic failure at both thresholds was significantly higher in 217 participants in the tenofovir-only group compared with 116 in the prior ART group using both cut-offs (24% vs. 7% with VL>40 copies/mL; 15% vs. 1% with VL>1000 copies/mL). Failure in the tenofovir-only group was associated with lower CD4 values and advanced WHO stage. In 35 available genotypes from 51 participants in the tenofovir-only group with VL>40 copies/mL (69% subtype A), any resistance was found in 89% and dual-class resistance in 83%. Tenofovir signature mutation K65R occurred in 71% (17/24) of the patients infected with subtype A. Patients with K65R had significantly lower CD4 values, higher WHO stage and more resistance mutations.

Conclusions

In this Kenyan cohort, tenofovir-based first-line ART resulted in good (90%) virologic suppression including high suppression (99%) after switch from non-tenofovir-based ART. Lower virologic suppression (85%) and high observed resistance levels (89%) in the tenofovir-only group impact future treatment options, support recommendations for widespread VL monitoring in such resource limited settings to identify early treatment failure and suggest consideration of individualized resistance testing to design effective subsequent regimens.

No Evidence That HIV-1 Subtype C Infection Compromises the Efficacy of Tenofovir-Containing Regimens: Cohort Study in the United Kingdom

Concern has been expressed that tenofovir-containing regimens may have reduced effectiveness in the treatment of human immunodeficiency virus type 1 (HIV-1) subtype C infections because of a propensity for these viruses to develop a key tenofovir-associated resistance mutation. We evaluated whether subtype influenced rates of virological failure in a cohort of 8746 patients from the United Kingdom who received a standard tenofovir-containing first-line regimen and were followed for a median of 3.3 years. In unadjusted analyses, the rate of failure was approximately 2-fold higher among patients infected with subtype C virus as compared to those with subtype B virus (hazard ratio [HR], 1.86; 95% confidence interval [CI], 1.50–2.31; P < .001). However, the increased risk was greatly attenuated in analyses adjusting for demographic and clinical factors (adjusted HR, 1.14; 95% CI, .83–1.58; P = .41). There were no differences between subtypes C and subtypes non-B and non-C in either univariate or multivariate analysis. These observations imply there is no intrinsic effect of viral subtype on the efficacy of tenofovir-containing regimens.

Short Communication: Limited HIV Pretreatment Drug Resistance Among Adults Attending Free Antiretroviral Therapy Clinic of Pune, India

In India, the roll out of the free antiretroviral therapy (ART) program completed a decade of its initiation in 2014. The success of first-line ART is influenced by prevalence of HIV pretreatment drug resistance (PDR) in the population. In this cross-sectional study, we sought to determine the prevalence of PDR among adults attending the state-sponsored free ART clinic in Pune in western India. Fifty-two individuals eligible for ART as per national guidelines with median CD4 cell count of 253 cells/mm(3) (inter quartile range: 149-326) were recruited between January 2014 and April 2015. Population-based sequencing of partial pol gene sequences from plasma specimen revealed predominant HIV-1 subtype C infection (96.15%) and presence of single-drug resistance mutations against non-nucleoside reverse transcriptase inhibitor in two sequences. The study supports the need for periodic surveillance, when offering PDR testing at individual level is not feasible.

Virological failure in patients with HIV-1 subtype C receiving antiretroviral therapy: an analysis of a prospective national cohort in Sweden

BACKGROUND

People with HIV-1 in low-income and middle-income countries increasingly need second-line regimens with boosted protease inhibitors. However, data are scarce for treatment response in patients with HIV-1 subtype C (HIV-1C), which is predominant in these regions. We aimed to examine factors associated with virological failure in patients in a standardised national health-care setting.

METHODS

We analysed data for participants in InfCare HIV, a prospective national cohort that includes more than 99% of people with HIV in Sweden. We extracted data for the cohort from the InfCare HIV database on Jan 14, 2015. Baseline was initiation of antiretroviral therapy. We used logistic regression to assess factors associated with primary virological failure (failure to suppress HIV-1 within 9 months) in patients with HIV-1B and HIV-1C and calculated odds ratios (OR) for failure. We also used Cox regression models to calculate hazard ratios (HR) for time-to-secondary virological failure (detectable viral load after initial virological suppression). We did homology-based molecular modelling to assess docking.

FINDINGS

We included 1077 patients with HIV-1B and 596 with HIV-1C. In multivariate regression analysis, pre-therapy higher viral load (OR 1·82, 95% CI 1·49-2·21; p<0·0001), subtype C infection (1·75, 1·06-2·88; p=0·028), and boosted protease inhibitor-based regimens (1·55, 1·45-2·11; p=0·004) were associated with increased risk of primary virological failure. Individuals with HIV-1C who were given therapy with boosted protease inhibitors had earlier time-to-secondary virological failure than did those with HIV-1B given similar regimens (adjusted HR 1·92, 95% CI 1·30-2·83; p=0·002). Molecular modelling suggested lower affinity for protease inhibitors to HIV-1C protease than to HIV-1B.

INTERPRETATION

Our findings suggest an increased risk of virological failure in patients with HIV-1C, especially in those on boosted protease inhibitor-based regimens. Future studies should further dissect the biochemical and viral mechanisms of resistance to protease inhibitors in patients with non-B subtypes of HIV-1, including clinical studies to assess the efficacy of boosted protease inhibitor-based regimens in low-income and middle income countries.

FUNDING

Karolinska Institutet Research Foundation, Swedish Research Council, Stockholm County Council, Swedish Physicians against AIDS, US National Institutes of Health, University of Missouri.

CD4 count-based failure criteria combined with viral load monitoring may trigger worse switch decisions than viral load monitoring alone

OBJECTIVE

CD4 count decline often triggers antiretroviral regimen switches in resource-limited settings, even when viral load testing is available. We therefore compared CD4 failure and CD4 trends in patients with viraemia with or without antiretroviral resistance.

METHODS

Retrospective cohort study investigating the association of HIV drug resistance with CD4 failure or CD4 trends in patients on first-line antiretroviral regimens during viraemia. Patients with viraemia (HIV RNA >1000 copies/ml) from two HIV treatment programmes in South Africa (n = 350) were included. We investigated the association of M184V and NNRTI resistance with WHO immunological failure criteria and CD4 count trends, using chi-square tests and linear mixed models.

RESULTS

Fewer patients with the M184V mutation reached immunologic failure criteria than those without: 51 of 151(34%) vs. 90 of 199 (45%) (P = 0.03). Similarly, 79 of 220 (36%) patients, who had major NNRTI resistance, had immunological failure, whereas 62 of 130 (48%) without (chi-square P = 0.03) did. The CD4 count decline among patients with the M184V mutation was 2.5 cells/mm(3) /year, whereas in those without M184V it was 14 cells/mm(3) /year (P = 0.1), but the difference in CD4 count decline with and without NNRTI resistance was marginal.

CONCLUSION

Our data suggest that CD4 count monitoring may lead to inappropriate delayed therapy switches for patients with HIV drug resistance. Conversely, patients with viraemia but no drug resistance are more likely to have a CD4 count decline and thus may be more likely to be switched to a second-line regimen.

Near Full-Length Genomic Characterization of a Novel CRF 01_AE/C Recombinant from Western India

HIV is known for its genetic variability across the globe. The HIV epidemic in India is primarily driven by subtype C, although sporadic circulating and unique recombinant forms are also reported from a few metropolitan cities in which genotyping facilities are available. Here we report a novel CRF01_AE/C recombinant from a multicenter study on the effectiveness of antiretroviral therapy (ART), 12 months after its initiation. Our subject is a 32-year-old heterosexual female, a native of Pune city in western India. Identification and analyses of recombination breakpoints using jpHMM@Gobics and SimPlot bootscanning revealed six recombination breakpoints, indicating insertion of the CRF01_AE genome at three points in the backbone of subtype C. Both subtype C and CRF01_AE are commonly seen in the population at risk of heterosexual HIV transmission, thereby providing an opportunity for cocirculation and recombination. The emergence of a novel recombinant of CRF01_AE/C is indicative of the increasing genetic diversity of the HIV epidemic in India.

Pretreatment HIV drug resistance increases regimen switches in sub-Saharan Africa

BACKGROUND

After the scale-up of antiretroviral therapy (ART) for human immunodeficiency virus (HIV) infection in Africa, increasing numbers of patients have pretreatment drug resistance.

METHODS

In a large multicountry cohort of patients starting standard first-line ART in six African countries, pol genotyping was retrospectively performed if viral load (VL) ≥1000 cps/mL. Pretreatment drug resistance was defined as a decreased susceptibility to ≥1 prescribed drug. We assessed the effect of pretreatment drug resistance on all-cause mortality, new AIDS events and switch to second-line ART due to presumed treatment failure, using Cox models.

RESULTS

Among 2579 participants for whom a pretreatment genotype was available, 5.5% had pretreatment drug resistance. Pretreatment drug resistance was associated with an increased risk of regimen switch (adjusted hazard ratio [aHR] 3.80; 95% confidence interval [CI], 1.49-9.68; P = .005) but was not associated with mortality (aHR 0.75, 95% CI, .24-2.35; P = .617) or new AIDS events (aHR 1.06, 95% CI, .68-1.64; P = .807). During three years of follow up, 106 (4.1%) participants switched to second-line, of whom 18 (17.0%) switched with VL < 1000 cps/mL, 7 (6.6%) with VL ≥ 1000 cps/mL and no drug resistance mutations (DRMs), 46 (43.4%) with VL ≥ 1000 cps/mL and ≥1 DRMs; no HIV RNA data was available for 32 (30.2%) participants.

CONCLUSIONS

Given rising pretreatment HIV drug resistance levels in sub-Saharan Africa, these findings underscore the need for expanded access to second-line ART. VL monitoring can improve the accuracy of failure detection and efficiency of switching practices.