Factors associated with virological success with raltegravir-containing regimens and prevalence of raltegravir-resistance-associated mutations at failure in the ARCA database

Long-term outcomes of highly experienced people with HIV undergoing salvage therapy with raltegravir

Raltegravir and other third-line drugs have shown promise in improving outcomes in treatment-experienced patients. However, the efficacy and tolerability of these agents vary. This study assessed real-life virologic success, long-term survival, and adverse events in patients receiving raltegravir or other third-line drugs as salvage regimens. This retrospective cohort study included adults who experienced treatment failure (human immunodeficiency syndrome-1 RNA plasma viral load >1000 copies/mL) and subsequently initiated raltegravir or other third-line drugs (darunavir/ritonavir, maraviroc, or etravirine). Propensity score matching methods were employed to account for differences at the time of switching from failing antiretroviral therapy regimens. The matched subset was analyzed using the Kaplan-Meier method and Generalized Wilcoxon tests to evaluate the probability of achieving virologic suppression (plasma viral load <50 copies/mL). Mortality rates, toxicity, treatment interruption, virologic failure, and loss to follow-up were determined using Poisson regression. One hundred and sixty-eight patients initiating salvage regimens were included, with 123 receiving raltegravir and 45 other third-line drugs. Propensity score matching resulted in a subset of 90 patients, 45 in each group. During the follow-up period, there were no significant differences observed between the groups in terms of virologic suppression (77.8% vs 82.2%, P = .73), mortality rates (4.04 vs 6.18 persons per 100 person-years [p-y]; P = .67), drug toxicity (0.00 vs 2.06 persons per 100 p-y; P = .49), treatment interruption (8.07 vs 0.00 persons per 100 p-y; P = .06), virologic failure (2.02 vs 4.12 persons per 100 p-y; P = .61), and loss of follow-up (6.05 vs 4.12 persons per 100 p-y; P = .70). Our findings indicate comparable survival and virological success rates between raltegravir and other drugs used in salvage regimens. Similar rates of drug toxicity, treatment interruption, virologic failure, and loss of follow-up were also observed. These results suggest that raltegravir may be a viable option for salvage therapy, demonstrating outcomes comparable to other third-line drugs in real life.

Baseline integrase drug resistance mutations and conserved regions across HIV-1 clades in Cameroon: implications for transition to dolutegravir in resource-limited settings

BACKGROUND

Transition to dolutegravir-based regimens in resource-limited settings (RLS) requires prior understanding of HIV-1 integrase variants and conserved regions. Therefore, we evaluated integrase drug resistance mutations (DRMs) and conserved regions amongst integrase strand transfer inhibitor (INSTI)-naive patients harbouring diverse HIV-1 clades in Cameroon.

METHODS

A cross-sectional study was conducted amongst 918 INSTI-naive patients from Cameroon (89 ART-naive and 829 ART-experienced patients). HIV-1 sequences were interpreted regarding INSTI-DRMs using the Stanford HIVdb v8.9-1 and the 2019 IAS-USA list. Amino acid positions with <1% variability were considered as highly conserved. Subtyping was performed by phylogeny.

RESULTS

Overall prevalence (95% CI) of INSTI-DRMs was 0.8% (0.4-1.7), with 0.0% (0.0-4.0) amongst ART-naive versus 0.9% (0.5-1.9) amongst ART-experienced patients; P = 0.44. Accessory mutations (95% CI) were found in 33.8% (30.9-37.0), with 38.2% (28.1-49.1) amongst ART-naive versus 33.4% (30.4-36.7) amongst ART-experienced patients; P = 0.21. Of 288 HIV-1 integrase amino acid positions, 58.3% were highly conserved across subtypes in the following major regions: V75-G82, E85-P90, H114-G118, K127-W132, E138-G149, Q168-L172, T174-V180, W235-A239 and L241-D253. Wide genetic diversity was found (37 clades), including groups M (92.3%), N (1.4%), O (6.2%) and P (0.1%). Amongst group M, CRF02_AG was predominant (47.4%), with a significantly higher frequency (95% CI) of accessory mutations compared with non-AG [41.4% (36.8-46.0) versus 27.1% (23.3-31.2) respectively; P < 0.001].

CONCLUSIONS

The low baseline of INSTI-DRMs (<1%) in Cameroon suggests effectiveness of dolutegravir-based regimens. In spite of high conservation across clades, the variability of accessory mutations between major circulating strains underscores the need for monitoring the selection of INSTI-DRMs while scaling up dolutegravir-based regimens in RLS.

Role of pretreatment variables on plasma HIV RNA value at the sixth month of antiretroviral therapy including all first line drugs in HIV naïve patients: A path analysis approach

BACKGROUND AND AIMS

We investigated the conditioning roles of viral tropism and other variables on plasma HIV RNA levels after 6 months of combination antiretroviral therapy (cART) in an HIV-infected Italian naïve population using regression tree, random forest regression, and path analysis (PA). Patients in this multicenter observational study were treated with all antiviral drugs that are currently recommended as first-line therapies.

METHODS

Adult patients with chronic HIV infection were enrolled at the beginning of first-line cART (T0). The main variables were age, gender, tropism, "lcd4_0" and "lcd4_6" (log10 CD4+counts at T0 and after 6 months of cART, respectively), and "lrna0" (log10 HIV RNA at T0). Regression tree and random forest analyses were applied. The predictive effect on lrna6 (log10-transformed plasma HIV RNA after 6 months of cART) was also investigated via PA (x4->lcd4_0->lrna0->lrna6) with a treatment selection step included as a dependent (mediator) variable for each third drug and, as predictive covariates, age, female, x4_10, x4_5, lcd4_0, and lrna0. Tropism was assessed in plasma using the Geno2pheno algorithm with 2 false positive rate (FPR) cut-offs: 5% (x4_5) and 10% (x4_10).

RESULTS

The study included 571 subjects (21% x4_10 and 10.7% x4_5). The only important predictor of lrna6 was lrna0, and a positive indirect effect of bearing X4 virus in plasma was suggested. A significant direct positive effect of protease inhibitors on lrna6 was found (p = 0.022), and a significant negative effect of integrase strand transfer inhibitor (INSTI) was also detected (p = 0.003 for FPR ≤ 5% and p = 0.01 for FPR < 10%). PA predicted mean residual viremias of 40 copies/mL without INSTI and 3 copies/mL with INSTI.

CONCLUSIONS

PA indicated a possible indirect role of HIV tropism on lrna6 with both FPR < 10% and ≤ 5%. Patients treated with INSTI had a predicted residual viremia of 3 copies/mL.

Prevalence and determinants of resistance mutations in HIV-1-infected patients exposed to integrase inhibitors in a large Italian cohort

OBJECTIVES

The aim of the study was to analyse the prevalence of integrase resistance mutations in integrase strand transfer inhibitor (INSTI)-experienced HIV-1-infected patients and its predictors.

METHODS

We selected HIV-1 integrase sequences from the Antiviral Response Cohort Analysis (ARCA) database, derived from INSTI-experienced patients between 2008 and 2017. Differences in the prevalence of resistance to raltegravir (RAL), elvitegravir (EVG) and dolutegravir (DTG) were assessed by χ² test and predictors of resistance were analysed by logistic regression.

RESULTS

We included 462 genotypes from INSTI-exposed individuals: 356 'INSTI-failing' patients and 106 'previously INSTI-exposed' patients (obtained a median of 42 weeks after INSTI discontinuation [interquartile range (IQR) 17-110 weeks]). Overall, at least low-level resistance (LLR) to any INSTI (Stanford 8.5 algorithm) was detected in 198 (42.9%) cases. The most frequent INSTI resistance mutation was N155H, followed by Q148H/K/R, G140A/C/S, E138A/K/T and Y143C/H/R. Y143R and E138A were more prevalent in viral subtype B versus non-B [5.2 versus 1.5%, respectively (P = 0.04), and 3.1 versus 0%, respectively (P = 0.02)]. Overall, the Q148H/K/R plus G140A/C/S and/or E138A/K/T pattern, defining an intermediate level of resistance to DTG, was detected in 70 (15%) cases. Independent predictors of at least LLR to any INSTI were current use versus past use of INSTIs, a lower genotypic sensitivity score (GSS) for contemporary antiretroviral drugs used, and having an integrase sequence obtained in calendar year 2016 as compared to 2008-2009.

CONCLUSIONS

The results support integrase resistance testing in INSTI-experienced patients. Emergence of INSTI resistance is facilitated by the reduced genetic barrier of the regimen as a consequence of resistance to companion drugs. However, INSTI resistance may become undetectable by standard population sequencing upon INSTI discontinuation.

Dolutegravir (DTG)-containing regimens after receiving raltegravir (RAL) or elvitegravir (EVG): Durability and virological response in a large Italian HIV drug resistance network (ARCA)

BACKGROUND

Dolutegravir (DTG) is a next-generation HIV integrase inhibitor (INI) with an increased genetic barrier to resistance with respect to raltegravir (RAL) or elvitegravir (EVG). Few data are available on the durability of DTG-containing regimens.

OBJECTIVES

We aimed at investigating the duration of the DTG-containing regimen, the occurrence of an HIV-1 RNA blip, and factors associated with DTG virological response.

STUDY DESIGN

From the Antiviral Response Cohort Analysis database, we selected 89 HIV-1-positive four-class-experienced subjects who started DTG after receiving RAL or EVG. Factors associated with durability and virological response were analysed by logistic regression.

RESULTS

After a median duration of 18.8 [0.4-76.2] months, 79/89 (88.8%) subjects were still on DTG. All subjects remaining on DTG at the end of follow-up had undetectable HIV-1 RNA, compared to 5/10 subjects who discontinued DTG. DTG discontinuation was less frequent in patients who had experienced ≥10 regimens (HR 0.11, p = 0.040). The probability of having an HIV-1 RNA positive value at the last follow-up significantly increased in patients with non-B HIV-1 subtype (HR 5.77, p < .001) and significantly decreased in patients with CD4 nadir >200/μL (HR 0.29, p = 0.038), with more than 10 previous regimens (HR 0.27, p = 0.040), and who harbored virus with IN mutations (HR 0.12, p = 0.023) at DTG start.

CONCLUSIONS

After previous exposure to first-generation INIs, treatment with DTG showed long durability and did not show virological rebound after virological suppression. Subjects infected with a non-B HIV-1 subtype had a greater risk of having detectable HIV-1 RNA at the last observation.

Effectiveness and Risk Factors for Virological Outcome of Raltegravir-Based Therapy for Treatment-Experienced HIV-Infected Patients

Objective

We evaluated the effectiveness of a raltegravir (RAL)-containing regimen plus an optimized background regimen in HIV-1 highly treatment-experienced patients.

Design

A retrospective cohort, multicentre study was conducted.

Methods

Adult (>16 years old) HIV treatment-experience patients starting therapy with a RAL-containing regimen were included. Effectiveness was evaluated as the percentage of patients with an undetectable HIV-1 RNA viral load (<50 and <200 copies/mL) after 48 weeks, and changes in CD4+ cell counts. We evaluated the risk factors associated with treatment failure.

Results

Of the 107 patients in the cohort, 86% were men, the median age was 45 years [interquartile range (IQR) 40–52] and the median number of previous regimens was six (IQR 4–7). After 48 weeks of treatment, 73% (IQR 63–80%) of patients (n = 78) had a viral load of <50 copies/mL and 85% (IQR 77–90%) (n = 91) had <200 copies/mL. In a logistic regression model, risk factors associated with a virological outcome of HIV-1 RNA of <200 copies/mL were age >40 years [odds ratio (OR) 5.61; 95% confidence interval (CI) 1.61–18.84; P = 0.006] and use of tenofovir in the regimen (OR 0.16; 95% CI 0.03–0.80; P = 0.026).

Conclusions

In this Mexican cohort, RAL achieved high rates of virological suppression and an increase in CD4+ cell count in highly treatment-experienced patients infected with HIV-1. Age >40 years was associated with a good virological outcome, contrary to tenofovir use, which was associated with a poor virological outcome.

Role of phenotypic investigation in the era of routine genotypic HIV-1 drug resistance testing

The emergence of drug resistance can seriously compromise HIV type-1 therapy and decrease therapeutic options. Resistance testing is highly recommended to guide treatment decisions and drug activity can be accurately predicted in the clinical setting through genotypic assays. While phenotypic systems are not suitable for monitoring drug resistance in routine laboratory practice, genotyping can misclassify unusual or complex mutational patterns, particularly with recently approved antivirals. In addition, phenotypic assays remain fundamental for characterizing candidate antiretroviral compounds. This review aims to discuss how phenotypic assays contributed to and still play a role in understanding the mechanisms of resistance of both licensed and investigational HIV type-1 inhibitors.

Larger is not necessarily better! Impact of HIV care unit characteristics on virological success: results from the French national representative ANRS-VESPA2 study

OBJECTIVES

To determine the impact of hospital caseload size on HIV virological success when taking into account individual patient characteristics.

METHODS

Data from the ANRS-VESPA2 survey representative of people living with HIV in France was used. Analyses were carried out on the 2612 (86.4% out of 3022) individuals receiving antiretroviral (ARV) treatment for at least one year. Outcomes correspond to two definitions of virological success (VS1 and VS2 respectively) and were analyzed under a multi-level modeling framework with a special focus on the effect of the caseload size on VS.

RESULTS

Structures with caseloads <1700 patients were more likely to have increased the proportion of patients achieving virological success (59% and 81% for VS1 and VS2, respectively) than structures whose caseloads numbered ≥1700 patients. Our results highlight that patients in the 11 largest care units in the sample were exposed to a context where their VS was potentially compromised by care unit characteristics, independently of both their individual characteristics and their own HIV treatment adherence behavior.

CONCLUSIONS

Our results suggest that - at least in the case of HIV care - in France large care units are not necessarily better. This result serves as an evidence-based warning to public authorities to ensure that health outcomes are guaranteed in an era when the French hospital sector is being substantially restructured.

Integrase inhibitor (INI) genotypic resistance in treatment-naive and raltegravir-experienced patients infected with diverse HIV-1 clades

OBJECTIVES

The aim of this study was to characterize the prevalence and patterns of genotypic integrase inhibitor (INI) resistance in relation to HIV-1 clade.

METHODS

The cohort comprised 533 INI-naive subjects and 255 raltegravir recipients with viraemia who underwent integrase sequencing in routine care across Europe, including 134/533 (25.1%) and 46/255 (18.0%), respectively, with non-B clades (A, C, D, F, G, CRF01, CRF02, other CRFs, complex).

RESULTS

No major INI resistance-associated mutations (RAMs) occurred in INI-naive subjects. Among raltegravir recipients with viraemia (median 3523 HIV-1 RNA copies/mL), 113/255 (44.3%) had one or more major INI RAMs, most commonly N155H (45/255, 17.6%), Q148H/R/K + G140S/A (35/255, 13.7%) and Y143R/C/H (12/255, 4.7%). In addition, four (1.6%) raltegravir recipients showed novel mutations at recognized resistance sites (E92A, S147I, N155D, N155Q) and novel mutations at other integrase positions that were statistically associated with raltegravir exposure (K159Q/R, I161L/M/T/V, E170A/G). Comparing subtype B with non-B clades, Q148H/R/K occurred in 42/209 (20.1%) versus 2/46 (4.3%) subjects (P = 0.009) and G140S/A occurred in 36/209 (17.2%) versus 1/46 (2.2%) subjects (P = 0.005). Intermediate- to high-level cross-resistance to twice-daily dolutegravir was predicted in 40/255 (15.7%) subjects, more commonly in subtype B versus non-B clades (39/209, 18.7% versus 1/46, 2.2%; P = 0.003). A glycine (G) to serine (S) substitution at integrase position 140 required one nucleotide change in subtype B and two nucleotide changes in all non-B clades.

CONCLUSIONS

No major INI resistance mutations occurred in INI-naive subjects. Reduced occurrence of Q148H/R/K + G140S/A was seen in non-B clades versus subtype B, and was explained by the higher genetic barrier to the G140S mutation observed in all non-B clades analysed.

HIV-1 integrase genotyping is reliable and reproducible for routine clinical detection of integrase resistance mutations even in patients with low-level viraemia

OBJECTIVES

Integrase drug resistance monitoring deserves attention because of the increasing number of patients being treated with integrase strand-transfer inhibitors. Therefore, we evaluated the integrase genotyping success rate at low-level viraemia (LLV, 51-1000 copies/mL) and resistance in raltegravir-failing patients.

METHODS

An integrase genotypic resistance test (GRT) was performed on 1734 HIV-1 samples collected during 2006-13. Genotyping success rate was determined according to the following viraemia levels: 51-500, 501-1000, 1001-10 000, 10 001-100 000 and >100 000 copies/mL. The reproducibility of integrase GRT was evaluated in 41 plasma samples processed in duplicate in two reference centres. The relationship between LLV and resistance prevalence was evaluated in a subset of 120 raltegravir-failing patients.

RESULTS

Overall, the integrase genotyping success rate was 95.7%. For viraemia levels 51-500 and 501-1000 copies/mL, the rate of success was 82.1% and 94.0%, respectively. GRT was reproducible, producing sequences with a high similarity and an equal resistance profile regardless of the sequencing centre or viraemia level. Resistance was detected both at LLV and at viraemia >1000 copies/mL (51-500 copies/mL = 18.2%; 501-1000 = 37.5%; 1001-10 000 = 53.7%; 10 001-100 000 = 30.0%; and >100 000 = 30.8%). At viraemia ≤500 copies/mL, Q148H/K/R and N155H had the same prevalence (9.1%), while the Y143C/H/R was completely absent. At early genotyping (within 3 months of raltegravir treatment), Q148H/K/R and N155H mutations were detected regardless of the viraemia level, while Y143C/H/R was observed only in samples with viraemia >1000 copies/mL.

CONCLUSIONS

Our findings prove the reliability of HIV-1 integrase genotyping and reinforce the concept that this assay may be useful in the management of failures even at LLV.