Time Of Virological Failure Research Articles

Delayed switch of antiretroviral therapy after virologic failure associated with elevated mortality among HIV-infected adults in Africa.

Routine monitoring of plasma HIV RNA among HIV-infected patients on antiretroviral therapy (ART) is unavailable in many resource-limited settings. Alternative monitoring approaches correlate poorly with virologic failure and can substantially delay switch to second-line therapy. We evaluated the impact of delayed switch on mortality among patients with virologic failure in Africa. A cohort. We examined patients with confirmed virologic failure on first-line nonnucleoside reverse transcriptase inhibitor (NNRTI)-based regimens from four cohorts with serial HIV RNA monitoring in Uganda and South Africa. Marginal structural models aimed to estimate the effect of delayed switch on mortality in a hypothetical trial in which switch time was randomly assigned. Inverse probability weights adjusted for measured confounders including time-updated CD4+ T-cell count and HIV RNA. Results: Among 823 patients with confirmed virologic failure, the cumulative incidence of switch 180 days after failure was 30% [95% confidence interval (CI) 27-33]. The majority of patients (74%) had not failed immunologically as defined by WHO criteria by the time of virologic failure. Adjusted mortality was higher for individuals who remained on first-line therapy than for those who had switched [odds ratio (OR) 2.1, 95% CI 1.1-4.2]. Among those without immunologic failure, the relative harm of failure to switch was similar (OR 2.4; 95% CI 0.99-5.8) to that of the entire cohort, although of borderline statistical significance. Among HIV-infected patients with confirmed virologic failure on first-line ART, remaining on first-line therapy led to an increase in mortality relative to switching. Our results suggest that detection and response to confirmed virologic failure could decrease mortality.

Comparison of Illumina and 454 Deep Sequencing in Participants Failing Raltegravir-Based Antiretroviral Therapy

BackgroundThe impact of raltegravir-resistant HIV-1 minority variants (MVs) on raltegravir treatment failure is unknown. Illumina sequencing offers greater throughput than 454, but sequence analysis tools for viral sequencing are needed. We evaluated Illumina and 454 for the detection of HIV-1 raltegravir-resistant MVs.MethodsA5262 was a single-arm study of raltegravir and darunavir/ritonavir in treatment-naïve patients. Pre-treatment plasma was obtained from 5 participants with raltegravir resistance at the time of virologic failure. A control library was created by pooling integrase clones at predefined proportions. Multiplexed sequencing was performed with Illumina and 454 platforms at comparable costs. Illumina sequence analysis was performed with the novel snp-assess tool and 454 sequencing was analyzed with V-Phaser.ResultsIllumina sequencing resulted in significantly higher sequence coverage and a 0.095% limit of detection. Illumina accurately detected all MVs in the control library at ≥0.5% and 7/10 MVs expected at 0.1%. 454 sequencing failed to detect any MVs at 0.1% with 5 false positive calls. For MVs detected in the patient samples by both 454 and Illumina, the correlation in the detected variant frequencies was high (R2 = 0.92, P<0.001). Illumina sequencing detected 2.4-fold greater nucleotide MVs and 2.9-fold greater amino acid MVs compared to 454. The only raltegravir-resistant MV detected was an E138K mutation in one participant by Illumina sequencing, but not by 454.ConclusionsIn participants of A5262 with raltegravir resistance at virologic failure, baseline raltegravir-resistant MVs were rarely detected. At comparable costs to 454 sequencing, Illumina demonstrated greater depth of coverage, increased sensitivity for detecting HIV MVs, and fewer false positive variant calls.

NRTI-sparing regimens yield higher rates of drug resistance than NRTI-based regimens for HIV-1 treatment.

To treat human immunodeficiency virus (HIV)-infected patients, international guidelines recommend the combination of two nucleos(t)ide reverse transcriptase inhibitors [N(t)RTIs] and a third agent [non-NRTI (NNRTI), boosted protease inhibitor (r/PI) or integrase inhibitor (INI)] for initial treatment. The objective of this study was to compare the selection of resistance to antiretrovirals (ARVs) for regimens containing or lacking N(t)RTIs in patients experiencing their first virological failure. Eligible patients had a first virological failure, defined as the occurrence of two consecutive HIV plasma viral loads ≥50copies/mL. Genotypic resistance testing was performed at the time of virological failure (on the second sample with detectable viral load ≥50copies/mL) in patients failing regimens of N(t)RTIs+r/PI or NNRTI or INI, r/PI+NNRTI or INI, and INI+NNRTI. Among 434 virological failures analysed, resistance testing results were available in 416 cases (95.9%). Higher rates of drug resistance were observed in patients receiving N(t)RTI-sparing regimens. When the combination of N(t)RTIs+r/PI was used, PIs protect themselves and the associated N(t)RTIs from the selection of resistance; however, this was not observed with the NNRTI+r/PI combination. The same phenomenon was observed for raltegravir: when used in combination with N(t)RTIs, INI resistance mutations were less frequently selected compared with its use in combination with PIs or NNRTIs. In conclusion, regimens of the ARV classes combined impact the frequency of resistance development. Lower resistance is observed for N(t)RTI-based regimens, with more therapeutic options for subsequent regimens after failure.

7.0 Managing virological failure

7.0 Managing virological failure

Evolution of the K65R, K103N and M184V/I reverse transcriptase mutations in HIV-1-infected patients experiencing virological failure between 2005 and 2010

To assess the prevalence of the K65R, K103N and M184V/I resistance mutations in the reverse transcriptase (RT) region in HIV-1-infected patients failing antiretroviral-based regimens between the years 2005 and 2010. HIV-1-infected patients experiencing virological failure between 2005 and 2010 with RT genotypic resistance tests available at the time of virological failure were analysed. K65R, K103N and M184V/I mutation frequencies were determined each year. Statistical analyses were performed using Fisher's exact test. Among 9586 patients failing their antiretroviral-based regimens from 2005 to 2010, the prevalence of K65R tended to decrease (P = 0.054), while K103N and M184V/I mutation frequencies decreased significantly over time (P < 0.001). The increased use of a tenofovir/emtricitabine/efavirenz single-tablet regimen was associated with decreased selection of these mutations. The global prevalence of resistance-associated mutations to tenofovir, lamivudine/emtricitabine and efavirenz decreased over time between 2005 and 2010. Despite a stable rate of efavirenz and protease inhibitor use, this phenomenon can be explained by an increased use of single-tablet regimens, which simplify drug intake and maximize adherence.

Drug‐resistance development differs between HIV‐1‐infected patients failing first‐line antiretroviral therapy containing nonnucleoside reverse transcriptase inhibitors with and without thymidine analogues

We evaluated the emergence of drug resistance in patients failing first-line regimens containing one nonnucleoside reverse transcriptase inhibitor (NNRTI) administered with zidovudine (ZDV) + lamivudine (the ZDV group) or non-thymidine analogues (non-TAs) (tenofovir or abacavir, + lamivudine or emtricitabine; the non-TA group). Three hundred HIV-1-infected patients failing a first-line NNRTI-containing regimen (nevirapine, n = 148; efavirenz, n = 152) were included in the analysis. Virological failure was defined as viraemia ≥ 400 HIV-1 RNA copies/mL for the first time at least 6 months after starting the NNRTI-based regimen. For each patient, a genotypic resistance test at failure was available. The presence of drug-resistance mutations in HIV-1 reverse transcriptase was evaluated by comparing patients treated with NNRTI + zidovudine + lamivudine vs. those treated with NNRTI + non-TA. A total of 208 patients were failing with NNRTI + zidovudine + lamivudine and 92 with NNRTI + non-TA. No significant differences were observed between the non-TA group and the ZDV group regarding the time of virological failure [median (interquartile range): 12 (8-25) vs. 13 (9-32) months, respectively; P = 0.119] and viraemia [median (interquartile range): 4.0 (3.2-4.9) vs. 4.0 (3.3-4.7) log₁₀ copies/mL, respectively; P = 0.894]. Resistance to reverse transcriptase inhibitors (RTIs) occurred at a significant lower frequency in the non-TA group than in the ZDV group (54.3 vs. 75.5%, respectively; P = 0.001). This difference was mainly attributable to a significantly lower prevalence of NNRTI resistance (54.3 vs. 74.0%, respectively; P = 0.002) and of the nucleoside reverse transcriptase inhibitor (NRTI) mutation M184V (23.9 vs. 63.5%, respectively; P < 0.001) in the non-TA group compared with the ZDV group. As expected, the mutation K65R was found only in the non-TA group (18.5%; P < 0.001). At first-line regimen failure, a lower prevalence of RTI resistance was found in patients treated with NNRTI + non-TA compared with those treated with NNRTI + zidovudine + lamivudine. These results confirm that the choice of backbone may influence the prevalence of drug resistance at virological failure.

Monitoring the emergence of resistance mutations in patients infected with HIV‐1 under salvage therapy with raltegravir in Rio de Janeiro, Brazil: A follow‐up study

The present study describes a follow-up of a prospective and observational cohort of patients infected with HIV-1 and treated with raltegravir for salvage therapy in Brazil. Two groups of patients were analyzed: switching from T20 to RAL (Group 1, n = 9) and salvage therapy containing RAL (Group 2, n = 10). Blood samples were drawn for CD4(+) T-cell counts and HIV-1 viral load determinations. Protease, reverse transcriptase, and integrase genotyping were performed at baseline and at the time of virologic failure. CD4(+) T-cells increased at 6 and 12 months in both groups; HIV-1 viral load was continuously suppressed for Group 1, and for Group 2 it significantly decreased after starting a RAL-containing regimen. Three out of 10 patients from Group 2 could not suppress HIV-1 viral load. The mutations Q148H + G140S were observed for two patients and for the third patient only mutations to PR/RT inhibitors were detected. The genotypic sensitivity score (GSS) was analyzed for all patients of Group 2 and both patients who developed resistance to raltegravir presented a GSS < 2.0 for the RAL-containing scheme, which could be associated to the lack of effectiveness of the proposed scheme. The present study describes, for the first time in Brazil, the close follow-up of a series of patients using a raltegravir-containing HAART, showing the safety of the enfuvirtide switch to RAL and the effectiveness of a therapeutic regimen with RAL in promoting immune reconstitution and suppressing HIV replication, as well as documenting the occurrence of resistance to integrase inhibitors in the country.

Detection of HIV-1 CXCR4 tropism and resistance in treatment experienced subjects receiving CCR5 antagonist—Vicriviroc

BackgroundVicriviroc (VCV), a small-molecule antagonist of the C–C chemokine receptor 5 (CCR5), blocks HIV's entry into CD4+ cells. Small studies have suggested that resistance to CCR5 antagonists is slow to develop. ObjectivesTo examine resistance to VCV in isolates from treatment experienced patients who experienced virologic failure in two phase 3 trials. Study designGenotypic and phenotypic susceptibility to VCV, and other antiretroviral drugs were evaluated at baseline and at defined intervals during the study. In a post hoc analysis, viral tropism at baseline was evaluated using the Trofile-ES assay. Only subjects with R5-tropic virus were included in the analysis. Viral envelope sequencing was performed on samples from subjects with emergent VCV resistance defined using a relative MPI cutoff. Results71/486 subjects treated with VCV for 48 weeks met the protocol-defined virologic failure criteria. 7/71 (10%) had DM/X4 virus at the time of virologic failure; VCV resistance was identified in 4/486 treated subjects (1%). No control subject had detectable DM/X4 virus or VCV resistance at virologic failure. Clonal analysis of envelope sequences from VCV-resistant virus identified 2–5 amino acid substitutions at or near the crown of the V3 loop; however, no signature V3 mutations were identified. Changes outside the V3 loop were also observed in resistant clones; no consistent variant pattern was observed. ConclusionsIn these trials, use of a sensitive tropism assay and potent antiretroviral drug combinations contributed to the infrequent detection of X4-tropic virus and VCV resistance. Substitutions in the V3 loop were associated with VCV resistance, however, no specific pattern of amino acid changes were sufficient to reliably predict VCV susceptibility.

Case report: Management and HBV sequencing in a patient co‐infected with HBV and HIV failing tenofovir

Nucleos(t)ide analogs such as tenofovir, lamivudine, or emtricitabine are active against both HBV and HIV. Tenofovir confers potent and durable HBV-DNA suppression but the best strategy in case of resistance of HBV to tenofovir remains unknown. A case of a 22-year-old patient with co-infection with HBV and HIV transmitted perinatally is reported. After prolonged and intermittent treatment of HIV with lamivudine and tenofovir, HBV became resistant to lamivudine. Subsequently, clinical resistance to tenofovir occurred, manifesting as HBV-DNA breakthrough. The non-compliance was reasonable excluded and HIV-RNA remained constantly suppressed. Entecavir (1 mg daily) was added and the combination therapy resulted in a rapid and continuous suppression of HBV-DNA for over 12 months. The treatment was well-tolerated and safe. No known mutations, such as rtA181T/V associated with rtN236T or A194T that are associated with reduced susceptibility or resistance to tenofovir were detected. However, a unique and complex HBV substitution pattern was found: with a development of rtR192PR mutation at the time of virological failure. Adding entecavir to failing therapy with tenofovir and emtricitabine was feasible, well-tolerated and resulted in virological success. The rtR192PR, which is located in the B domain near the rtA194T, occurring in a context of a very complex substitutions patterns, might be associated with resistance to tenofovir.

Nevirapine versus Ritonavir-Boosted Lopinavir for HIV-Infected Children

BackgroundNevirapine-based antiretroviral therapy is the predominant (and often the only) regimen available for children in resource-limited settings. Nevirapine resistance after exposure to the drug for prevention of maternal-to-child human immunodeficiency virus (HIV) transmission is common, a problem that has led to the recommendation of ritonavir-boosted lopinavir in such settings. Regardless of whether there has been prior exposure to nevirapine, the performance of nevirapine versus ritonavir-boosted lopinavir in young children has not been rigorously established.MethodsIn a randomized trial conducted in six African countries and India, we compared the initiation of HIV treatment with zidovudine, lamivudine, and either nevirapine or ritonavir-boosted lopinavir in HIV-infected children 2 to 36 months of age who had no prior exposure to nevirapine. The primary end point was virologic failure or discontinuation of treatment by study week 24.ResultsA total of 288 children were enrolled; the median percentage of CD4+ T cells was 15%, and the median plasma HIV type 1 (HIV-1) RNA level was 5.7 log10 copies per milliliter. The percentage of children who reached the primary end point was significantly higher in the nevirapine group than in the ritonavir-boosted lopinavir group (40.8% vs. 19.3%; P<0.001). Among the nevirapine-treated children with virologic failure for whom data on resistance were available, more than half (19 of 32) had resistance at the time of virologic failure. In addition, the time to a protocol-defined toxicity end point was shorter in the nevirapine group (P=0.04), as was the time to death (P=0.06).ConclusionsOutcomes were superior with ritonavir-boosted lopinavir among young children with no prior exposure to nevirapine. Factors that may have contributed to the suboptimal results with nevirapine include elevated viral load at baseline, selection for nevirapine resistance, background regimen of nucleoside reverse-transcriptase inhibitors, and the standard ramp-up dosing strategy. The results of this trial present policymakers with difficult choices. (Funded by the National Institute of Allergy and Infectious Diseases and others; P1060 ClinicalTrials.gov number, NCT00307151.)

Resistance profiles of emtricitabine and lamivudine in tenofovir-containing regimens

To compare the frequency of the selection of the M184V/I resistance mutation in HIV-infected patients who experienced virological failure while receiving emtricitabine (FTC) or lamivudine (3TC), administered with tenofovir disoproxil fumarate (TDF) and either efavirenz (EFV) or a ritonavir-boosted protease inhibitor (PI; lopinavir or atazanavir). Patient data held at two clinical centres in France were analysed retrospectively. Eligible patients had experienced virological suppression (plasma HIV RNA <200 copies/mL) for ≥ 6 months before experiencing their first virological failure (at least two measurements of plasma HIV RNA ≥ 200 copies/mL). Of the 880 patients eligible for the study, 278 patients had experienced virological failure while receiving FTC + TDF + ritonavir-boosted PI, 257 while receiving FTC + TDF + EFV, 178 while receiving 3TC + TDF + EFV and 167 while receiving 3TC + TDF + ritonavir-boosted PI. Proportions of patients harbouring the M184V/I mutation were 24% (n = 62) for those who received FTC + TDF + EFV versus 51% (n = 91) for 3TC + TDF + EFV (P < 0.0001; Fisher's exact test); proportions were 11% (n = 30) for FTC + TDF + ritonavir-boosted PI versus 22% (n = 37) for 3TC + TDF + ritonavir-boosted PI (P = 0.002; Fisher's exact test). The use of lamivudine versus emtricitabine (P = 0.001), non-nucleoside reverse transcriptase inhibitors versus ritonavir-boosted PIs (P = 0.01) and the level of viral load at the time of virological failure (P = 0.01) were associated with selection of the M184V/I mutation (logistic regression analysis). Emtricitabine and lamivudine showed differing resistance profiles when administered in combination with tenofovir disproxil fumarate and either efavirenz or a ritonavir-boosted PI. The prevalence of the M184V/I resistance mutation was significantly lower in patients who received emtricitabine and tenofovir disoproxil fumarate than in those who received lamivudine and tenofovir disoproxil fumarate.

G140S/Q148R and N155H mutations render HIV-2 Integrase resistant to Raltegravir whereas Y143C does not

BackgroundHIV-2 is endemic in West Africa and has spread throughout Europe. However, the alternatives for HIV-2-infected patients are more limited than for HIV-1. Raltegravir, an integrase inhibitor, is active against wild-type HIV-2, with a susceptibility to this drug similar to that of HIV-1, and is therefore a promising option for use in the treatment of HIV-2-infected patients. Recent studies have shown that HIV-2 resistance to raltegravir involves one of three resistance mutations, N155H, Q148R/H and Y143C, previously identified as resistance determinants in the HIV-1 integrase coding sequence. The resistance of HIV-1 IN has been confirmed in vitro for mutated enzymes harboring these mutations, but no such confirmation has yet been obtained for HIV-2.ResultsThe integrase coding sequence was amplified from plasma samples collected from ten patients infected with HIV-2 viruses, of whom three RAL-naïve and seven on RAL-based treatment at the time of virological failure. The genomes of the resistant strains were cloned and three patterns involving N155H, G140S/Q148R or Y143C mutations were identified. Study of the susceptibility of integrases, either amplified from clinical isolates or obtained by mutagenesis demonstrated that mutations at positions 155 and 148 render the integrase resistant to RAL. The G140S mutation conferred little resistance, but compensated for the catalytic defect due to the Q148R mutation. Conversely, Y143C alone did not confer resistance to RAL unless E92Q is also present. Furthermore, the introduction of the Y143C mutation into the N155H resistant background decreased the resistance level of enzymes containing the N155H mutation.ConclusionThis study confirms that HIV-2 resistance to RAL is due to the N155H, G140S/Q148R or E92Q/Y143C mutations. The N155H and G140S/Q148R mutations make similar contributions to resistance in both HIV-1 and HIV-2, but Y143C is not sufficient to account for the resistance of HIV-2 genomes harboring this mutation. For Y143C to confer resistance in vitro, it must be accompanied by E92Q, which therefore plays a more important role in the HIV-2 context than in the HIV-1 context. Finally, the Y143C mutation counteracts the resistance conferred by the N155H mutation, probably accounting for the lack of detection of these mutations together in a single genome.

Antiretroviral resistance patterns and factors associated with resistance in adult patients failing NNRTI‐based regimens in the western cape, South Africa

Antiretroviral drug resistance in patients failing non-nucleoside reverse transcriptase inhibitor (NNRTI)-based first-line combination antiretroviral treatment (ART) is influenced by: regimen choice, HIV-1 subtype, detection of and response to therapy failure. In order to describe resistance patterns by genotypic testing, at the time of first-line ART failure and to describe associations with having M184I/V, K65R, three or more thymidine analog mutations (TAMs) and etravirine (ETV) resistance, the prevalence of antiretroviral drug resistance associated mutations in a cross-sectional study, at two South African public health clinic settings, at the time of virologic failure (HIV-1 RNA load >400 copies/ml) are described. Also reported are associations of therapy choice, prolonged virologic failure, and concurrent HIV viral load and CD4 count with the presence of M184I/V, TAMs, K65R, and resistance to ETV. Of 167 adult patients with virologic failure on first-line ART, 28 (17%) had no resistance, 137 (82%) had NNRTI resistance, 101 (60%) M184I/V, 20 (12%) TAMs, of which 4 had 3 or more TAMs, and 7 (4%) had K65R, of which 6 were on D4T and one on AZT. A prolonged estimated period of failure was associated with having ≥3 TAMs. Patients treated with nevirapine (NVP) were more likely to have ETV resistance than those treated with efavirenz (EFV). Major protease inhibitor mutations were not detected. A delayed response to ART failure may risk accumulation of TAMs in patients on an NNRTI-based regimen. The use of NVP rather than EFV was associated with ETV resistance.

Dynamics of enfuvirtide resistance mutations in enfuvirtide-experienced patients remaining in virological failure under salvage therapy

Evaluation of the dynamics of enfuvirtide (ENF) resistance mutations after ENF withdrawal in patients with virological failure under salvage therapy may be helpful to optimize the management of ENF in human immunodeficiency virus (HIV)-infected patients. Seven patients with a failing ENF-containing regimen, initiated for at least 3 months (median 6.4 months, range 3-14), were included and followed up prospectively at the time of virological failure. Genotypic analysis of the gp41 region by bulk sequencing and clonal analysis was performed in plasma and/or peripheral blood mononuclear cells to detect ENF resistance mutations. Genotypic profiles of ENF-resistant variants at ENF discontinuation were as follows: V38A in 3 patients, V38A+N42T+N43D in 1 patient, N43D in 2 patients, and N43K in 1 patient. Clonal analysis showed that maintaining ENF treatment after virological failure has an impact on both (1) the number of resistance profiles detected, and (2) the time of persistence of ENF-resistant variants. ENF-resistant variants were archived in HIV DNA in 5/7 patients. At 1 month after ENF withdrawal, no significant increase in HIV-1 viral load was observed. The persistence of ENF-resistant variants was found to be correlated to exposure time to failing drug. ENF withdrawal should be considered in patients with virological failure to preserve the possible efficacy of ENF recycling or upcoming entry inhibitors.

Characterization of HIV‐1 from patients with virological failure to a boosted protease inhibitor regimen

The use of highly active antiretroviral treatment (HAART) regimens with unboosted protease inhibitors (PIs) has resulted in a high level of virological failure primarily due to the development of resistant virus. Current boosted PI regimens combine successfully low-dose ritonavir (r) with a second PI. The aim of the study was to estimate the proportion of patients, in a population based setting, who develop virological failure on a PI/r regimen. Through The Danish HIV Cohort Study 1,007 patients who received PI/r based treatment between 1995 and 2008 were identified. Twenty-three (2.3%) experienced virological failure, of whom 19 (83%) started PI/r treatment before 2001. Patients from Copenhagen (n=19) were selected to study the development of protease (PR) and gag cleavage site (CS) mutations during PI/r treatment and PI plasma levels at the time of virological failure. Three patients (16%) developed major PI resistance mutations. Mutations in the p7/p1 and p1/p6 gag CS only developed in patients with major or minor mutations in PR. Drug concentrations were low or undetectable in 10 out of the 19 patients. In total PR resistance mutations and low drug levels could account for 12 (63%) of the failure cases. In conclusion, virological failure to PI/r is a low and decreasing problem primarily caused by low plasma drug levels and to a lesser extent major PR mutations. Gag CS mutations did not contribute significantly to resistance development and virological failure.

Suboptimal use of HIV drug resistance testing in a universal health-care setting

HIV drug resistance testing is recommended as routine part of clinical practice in HIV/AIDS treatment and care. Our objective is to assess the determinants of accessing HIV drug resistance testing and examine the factors associated with resistance testing prior to or after starting highly active antiretroviral therapy (HAART) in a setting where access to HIV care is free and universal. The Longitudinal Investigation into Supportive and Ancillary health services (LISA) study is an open prospective cohort of HIV-positive persons on HAART in British Columbia (BC), Canada. Non-clinical data were collected through an interviewer-administered survey and clinical data were obtained through the BC Centre for Excellence in HIV/AIDS Drug Treatment Program. Independent associations between key explanatory variables and resistance testing were analyzed using logistic regression. We restricted our post-HAART analyses to those patients who met the criteria for resistance testing after HAART initiation. Of 359 LISA participants who started HAART after 2000 and at a time when resistance testing was available free of charge, almost half did not receive a baseline resistance test. Post-HAART initiation, 165 of 359 study subjects met the criteria for resistance testing based on current therapeutic guidelines due to virological failure. About 37.6% of them remain untested for resistance. Multivariable analyses show that baseline testing was less likely performed for persons of Aboriginal ethnicity and more likely performed for patients initiating HAART in 2004 or after. Additionally, persons initiating HAART in 2004 or after were less likely to have received a resistance test after virologic failure. Our results show that despite existing clinical guidelines, resistance testing is underused, even in an environment where the service is available free of charge. Further, resistance testing is particularly underutilized among vulnerable populations. Urgent efforts are needed to ensure the optimal use of resistance testing at baseline and at the time of virologic failure as recommended by current guidelines.

Hot Spots of Integrase Genotypic Changes Leading to HIV-2 Resistance to Raltegravir

We studied seven heavily pretreated HIV-2-infected patients exhibiting a virological failure while receiving a salvage raltegravir-containing regimen. At the time of virological failure, different resistance genetic pathways were observed: T97A-Y143C, Q148K, Q148R, G140S-Q148R, E92Q-Y143R-N155H, and T97A-N155H. Thus, despite a 40% difference in integrase genes between HIV-1 and HIV-2, the genetic pathways leading to raltegravir resistance are similar.

Resistance analyses in highly experienced patients failing raltegravir, etravirine and darunavir/ritonavir regimen

ANRS 139 TRIO trial was a phase II noncomparative trial that evaluated in highly experienced patients, a combination of raltegravir, etravirine and darunavir boosted with ritonavir. We analyzed emergence of resistant viruses at the time of virological failure and investigated the impact of baseline integrase polymorphisms on virological failure occurrence. Bulk sequencing of protease, reverse transcriptase and integrase genes was performed for 103 patients at baseline and 14 patients at the time of virological failure. Additionally, integrase clonal analyses were performed at baseline and at virological failure in patients with successful integrase gene amplification. Impact of baseline integrase polymorphisms on virological failure occurrence was analyzed using Fisher exact and Wilcoxon tests. In the 14 failing patients median viral load at virological failure was 90 copies/ml (interquartile range = 60-783). Emergence of darunavir and etravirine resistance mutations was observed at virological failure in only one and three patients, respectively. Raltegravir resistance mutations were found neither at baseline nor at the time of virologic failure. Integrase clonal analyses showed neither the presence nor the selection of minority variants carrying raltegravir resistance mutations at baseline or at virological failure. No impact of baseline integrase polymorphisms was observed on virological failure either at week 24 or at week 48. Virological failure occurred in a small proportion of patients with low viral load. No raltegravir resistance mutations were observed using bulk sequencing or clonal analyses, and darunavir and etravirine resistance-associated mutations were detected in only one and three patients, respectively at virological failure. No impact of baseline integrase polymorphism was observed on virological failure occurrence.

Relating protease inhibitor resistance at time of virological failure with drug exposure

7‐11 November 2010, Tenth International Congress on Drug Therapy in HIV Infection, Glasgow, UK

Patient-Selected Treatment Partners Did Not Protect Against Drug Resistance During First-Line NNRTI-Based HAART in a Randomized Trial

Patient-Selected Treatment Partners Did Not Protect Against Drug Resistance During First-Line NNRTI-Based HAART in a Randomized Trial