Evaluation of integrase resistance in individuals who failed a regimen containing dolutegravir in French and Italian clinical settings.

BACKGROUND: This work aims to evaluate integrase resistance and its predictors in HIV-1 infected combined antiretroviral therapy (cART) experienced individuals failing a dolutegravir-based regimen. METHODS: Major resistance mutations (MRM) and genotypic susceptibility score (GSS) of dolutegravir companion drugs were evaluated on plasma genotypic resistance test (GRT) performed at dolutegravir failure. Logistic regression was used to evaluate factors associated to the risk of integrase strand-transfer inhibitors (INSTI)-resistance at dolutegravir failure. RESULTS: We retrospectively analysed 467 individuals. At failure GRT, individuals had been under dolutegravir for a median (IQR) time of 11 (5-20) months; around half of them had never been exposed to INSTI (52%) and 10.7% were at first-line regimen. Fifty-eight (12.4%) individuals showed ≥1 INSTI MRM. Among them, people INSTI-exposed showed significantly higher prevalence of INSTI resistance compared to those who were INSTI naïve [46 (21.2%) versus 9 (3.9%), P < 0.001].N155H was the most prevalent MRM (5.4%), followed by G140S (4.5%) and Q148H (4.3%). These MRM were more probably present in INSTI-experienced individuals compared to those INSTI naïve. Despite failure, 89.5% of individuals harboured viral strains fully susceptible to dolutegravir and bictegravir and 85.0% to all INSTI. No INSTI exposure before receiving dolutegravir [OR: 0.35 (0.16-0.78), P < 0.010] and a GSS for companion drugs ≥2 (OR: 0.09 [0.04-0.23], P < 0.001) were negatively associated with INSTI resistance at failure. CONCLUSIONS: In a large set of individuals failing dolutegravir in real-life, INSTI resistance was low and mainly related to previous first-generation INSTI exposure. Surveillance of integrase resistance remains crucial to preserve efficacy of INSTI class in the future.

Low-level viral loads and virological failure in the integrase strand transfer era.

OBJECTIVES: To analyse the occurrence of virological failure (VF) in patients starting ART with an integrase strand transfer inhibitor (INSTI)-based regimen in recent years, in relation with previous episodes of low-level viral load (LLVL). PATIENTS AND METHODS: Patients starting a first ART between 1 January 2015 and 31 December 2020 based on two NRTIs and one INSTI were included if after virological control (two measures of VL < 50 copies/mL) they had a minimum of two additional VL measurements. Cox models adjusted for sex, age, acquisition group, hepatitis B or C coinfection, place of birth, year of ART initiation, CD4+ T cells and VL at ART initiation, duration of known HIV infection and of ART regimen were used to assess the association between the time to VF and the occurrence of LLVL. ART regimen was evaluated as time-varying covariate. RESULTS: LLVL was described in 13.7% and VF in 11% of the 3302 patients. LLVL was associated with VF [adjusted HR (aHR) 1.76, 95% CI 1.28-2.41], as well as age (aHR 0.97/year, 95% CI 0.96-0.98), CD4+ T cell count at ART initiation (aHR 0.93, 95% CI 0.87-0.98), heterosexual transmission (aHR 1.76, 95% CI 1.30-2.37) and being born abroad (aHR 1.50, 95% CI 1.17-1.93). CONCLUSIONS: LLVL was related to VF. Even in the absence of subsequent failure, LLV episodes have a cost. Thus any VL value above 50 copies/mL should lead to enhanced adherence counselling.

SARS-CoV-2 Neutralizing Responses in Various Populations, at the Time of SARS-CoV-2 Variant Virus Emergence: Evaluation of Two Surrogate Neutralization Assays in Front of Whole Virus Neutralization Test.

The SARS-CoV-2 neutralizing antibodies response is the best indicator of effective protection after infection and/or vaccination, but its evaluation requires tedious cell-based experiments using an infectious virus. We analyzed, in 105 patients with various histories of SARS-CoV-2 infection and/or vaccination, the neutralizing response using a virus neutralization test (VNT) against B.1, Alpha, Beta and Omicron variants, and compared the results with two surrogate assays based on antibody-mediated blockage of the ACE2-RBD interaction (Lateral Flow Boditech and ELISA Genscript). The strongest response was observed for recovered COVID-19 patients receiving one vaccine dose. Naïve patients receiving 2 doses of mRNA vaccine also demonstrate high neutralization titers against B.1, Alpha and Beta variants, but only 34.3% displayed a neutralization activity against the Omicron variant. On the other hand, non-infected patients with half vaccination schedules displayed a weak and inconstant activity against all isolates. Non-vaccinated COVID-19 patients kept a neutralizing activity against B.1 and Alpha up to 12 months after recovery but a decreased activity against Beta and Omicron. Both surrogate assays displayed a good correlation with the VNT. However, an adaptation of the cut-off positivity was necessary, especially for the most resistant Beta and Omicron variants. We validated two simple and reliable surrogate neutralization assays, which may favorably replace cell-based methods, allowing functional analysis on a larger scale.

Decreased Sensitivity of Rapid Antigen Test Is Associated with a Lower Viral Load of Omicron than Delta SARS-CoV-2 Variant.

Large-scale screening for SARS-CoV-2 infection is an important tool for epidemic prevention and control. The appearance of new variants associated with specific mutations can call into question the effectiveness of rapid diagnostic tests (RDTs) deployed massively at national and international levels. We compared the clinical and virological characteristics of individuals infected by Delta or Omicron variants to assess which factors were associated with a reduced performance of RDT. A commercially available RDT as well as the evaluation of the viral load (VL) and the detection of replicate intermediates (RIs) were carried out retrospectively on positive SARS-CoV-2 nasopharyngeal specimens from health care workers of the Pitié-Salpêtrière Hospital infected by the Delta or Omicron variant between July 2021 and January 2022. Of the 205 samples analyzed (104 from individuals infected with Delta and 101 with Omicron), 176 were analyzed by RDT and 200 by RT-PCR for VL and RIs. The sensitivity of the TDR for Omicron was significantly lower than that observed for Delta (53.8% versus 74.7%, respectively, P < 0.01). Moreover, the Delta VL was significantly higher than that measured for Omicron (median Ct 21.2 versus 24.1, respectively, P < 0.01) and associated with the positivity of the RDT in multivariate analysis. We demonstrate a lower RDT sensitivity associated with a lower VL at the time of diagnosis on Omicron-infected individuals in comparison to those infected with the Delta variant. This RDT lower sensitivity should be taken into account in the large-scale screening strategy and in particular in case of strong suspicion of infection where testing should be repeated. IMPORTANCE Previous reports have shown a variability in the diagnostic performance of RDTs. In the era of SARS-CoV-2 variants and the use of RDT, mutation associated with these variants could affect the test performance. We evaluate the sensitivity of the RDT Panbio COVID-19 Ag (Abbott) with two variants of concern (VOC), the Delta and Omicron variants. In order to investigate whether clinical characteristics or virological characteristics can affect this sensitivity, we collected clinical information and performed a specific RT-PCR that detected the RIs as a marker of the viral replication and viral cycle stage. Our results showed that Omicron was less detected than the Delta variant. A lower viral load of Omicron variant in comparison to Delta variant explained this decreased sensitivity, even if they are at the same stage of the disease and the viral cycle and should be taken into account with the use of RDT as diagnostic tool.

Weighted log-rank test to compare two survival functions in the presence of dependent censoring.

Comparing survival functions with the log-rank test in the presence of dependent censoring can produce an invalid test result. We extend our previous work on the estimation of the survival function using prognostic variables to adjust for dependent censoring to the comparison of two survival distributions. In these estimators, the weights of a censored individual is redistributed among either a subset of patients in the risk set or all patients in the risk set but giving more weight to patients having smallest distances from the censored subject. The distance is based on two risk scores obtained from two working models, one for the failure time and one for the censoring time. Based on the estimators, we suggest a weighted log-rank test to compare two survival distributions. A simulation study compared performance of our method with the analysis of the observed data without using auxiliary variables and with a recent method based on multiple imputation (KMIB method). With appropriate parameters, the weighted log-rank approach provides sizes of the test comparable to the nominal value but higher powers than the two other methods. The method is illustrated with data from a breast cancer study.

Factors associated with the emergence of integrase resistance mutations in patients failing dual or triple integrase inhibitor-based regimens in a French national survey.

BACKGROUND: Successful 2-drug regimens (2DRs) for HIV were made possible by the availability of drugs combining potency and tolerability with a high genetic barrier to resistance. How these deal with resistance development/re-emergence, compared with 3DRs, is thus of paramount importance. MATERIALS AND METHODS: A national survey including patients who were either naive or experienced with any 2DR or 3DR but failing integrase strand transfer inhibitor (INSTI)-containing regimens [two consecutive plasma viral load (VL) values >50 copies/mL] was conducted between 2014 and 2019. Genotypic resistance tests were interpreted with the v28 ANRS algorithm. RESULTS: Overall, 1104 patients failing any INSTI-containing regimen (2DRs, n = 207; 3DRs, n = 897) were analysed. Five hundred and seventy-seven (52.3%) patients were infected with a B subtype and 527 (47.3%) with non-B subtypes. Overall, 644 (58%) patients showed no known integrase resistance mutations at failure. In multivariate analysis, factors associated with the emergence of at least one integrase mutation were: high VL at failure (OR = 1.24 per 1 log10 copies/mL increase); non-B versus B subtype (OR = 1.75); low genotypic sensitivity score (GSS) (OR = 0.10 for GSS = 2 versus GSS = 0-0.5); and dolutegravir versus raltegravir (OR = 0.46). Although 3DRs versus 2DRs reached statistical significance in univariate analysis (OR = 0.59, P = 0.007), the variable is not retained in the final model. CONCLUSIONS: This study is one of the largest studies characterizing integrase resistance in patients failing any INSTI-containing 2DR or 3DR in routine clinical care and reveals factors associated with emergence of integrase resistance that should be taken into consideration in clinical management. No difference was evidenced between patients receiving a 2DR or a 3DR.

Linezolid-Associated Neurologic Adverse Events in Patients with Multidrug-Resistant Tuberculosis, France.

Linezolid is one of the most effective drugs for treating multidrug-resistant tuberculosis (MDR TB), but adverse effects remain problematic. We evaluated 57 MDR TB patients who had received >1 dose of linezolid during 2011-2016. Overall, patients received 600 mg/day of linezolid for a median of 13 months. In 33 (58%) patients, neurologic or ophthalmologic signs developed, and 18 (32%) had confirmed peripheral neuropathy, which for 78% was irreversible at 12 months after the end of TB treatment despite linezolid withdrawal. Among the 19 patients who underwent ophthalmologic evaluation, 14 patients had optic neuropathy that fully reversed for 2. A total of 16 (33%) of 49 patients had a linezolid trough concentration >2 mg/L, and among these, 14 (88%) experienced adverse effects. No significant association was found between trough concentration and neurologic toxicity. These findings suggest the need to closely monitor patients for neurologic signs and discuss optimal duration of linezolid treatment.

Weighted Kaplan-Meier estimators motivating to estimate HIV-1 RNA reduction censored by a limit of detection.

Measuring the magnitude of reduction in HIV-1 RNA levels accurately is difficult because many patients have a censored reduction due to the limit of detection (LOD) of the virologic assay being employed. The use of censored methods has improved the analysis of such reductions compared with crude methods but implies independent censoring. For HIV-1 RNA reduction data, the value at which a patient's HIV-1 RNA reduction becomes censored is mainly determined by the patient's baseline HIV-1 RNA level. We suggest two possibilities based on modification of the redistribution to the right algorithm to handle the situation of dependence either from a single continuous marker, that is, the baseline HIV-1 RNA level, or from multiple markers. Two series of simulation, one in the HIV-1 RNA setting and one in the classical censoring setting, compared performance of the previous methods with our suggestions. Our proposed estimators show good performances when the dependent censoring is due to LOD. Overall, in the classical censoring setting, our suggestions perform as well as other methods including the Inverse Probability of Censoring Weighted and the Kaplan-Meier imputation with Bootstrap. We applied those estimators to estimate the HIV-1 RNA reduction at week 8 of 502 patients who received a raltegravir-containing regimen and to data from the Mayo Clinic trial in primary biliary cirrhosis.

Resistance to integrase inhibitors: a national study in HIV-1-infected treatment-naive and -experienced patients.

OBJECTIVES: To describe integrase strand transfer inhibitor (INSTI) resistance profiles and factors associated with resistance in antiretroviral-naive and -experienced patients failing an INSTI-based regimen in clinical practice. METHODS: Data were collected from patients failing an INSTI-containing regimen in a multicentre French study between 2014 and 2017. Failure was defined as two consecutive plasma viral loads (VL) >50 copies/mL. Reverse transcriptase, protease and integrase coding regions were sequenced at baseline and failure. INSTI resistance-associated mutations (RAMs) included in the Agence Nationale de Recherches sur le SIDA genotypic algorithm were investigated. RESULTS: Among the 674 patients, 359 were failing on raltegravir, 154 on elvitegravir and 161 on dolutegravir therapy. Overall, 90% were experienced patients and 389 (58%) patients showed no INSTI RAMs at failure. The strongest factors associated with emergence of at least one INSTI mutation were high VL at failure (OR = 1.2 per 1 log10 copies/mL increase) and low genotypic sensitivity score (GSS) (OR = 0.08 for GSS ≥3 versus GSS = 0-0.5). Patients failing dolutegravir also had significantly fewer INSTI RAMs at failure than patients failing raltegravir (OR = 0.57, P = 0.02) or elvitegravir (OR = 0.45, P = 0.005). Among the 68 patients failing a first-line regimen, 11/41 (27%) patients on raltegravir, 7/18 (39%) on elvitegravir and 0/9 on dolutegravir had viruses with emergent INSTI RAMs at failure. CONCLUSIONS: These results confirmed the robustness of dolutegravir regarding resistance selection in integrase in the case of virological failure in routine clinical care.

The Use of the Restricted Mean Survival Time as a Treatment Measure in HIV/AIDS Clinical Trial: Reanalysis of the ACTG A5257 Trial.

BACKGROUND: The restricted mean survival time (RMST) measures have not been used as primary measure of efficacy in HIV/AIDS clinical trials. In this work, we aim to compare analysis based on the difference in RMST (Δ-RMST) measure and 2 other treatment-effect measures in a recent HIV equivalence trial, and to investigate the performance and characteristics of Δ-RMST-based analysis in a simulation study. SETTING AND METHODS: We reanalyzed a recent HIV equivalence trial (ACTG A5257 trial) with hazard ratio and Δ-RMST, and then compared the results with the original analysis based on risk difference estimated by Kaplan-Meier curves (RDKM). In a simulation study, we investigated the performance and operating characteristics of Δ-RMST-based analysis in the setting of non-proportional hazards (PH) ratio. RESULTS: In the ACTG A5257 trial, analyses based on Δ-RMST globally led to similar conclusions as the published finding based on RDKM. By contrast, analyses based on hazard ratio provided some discordant equivalence conclusions compared both with the initial analyses based on RDKM and the Δ-RMST. Results of simulation study indicate that the violation of the PH assumption has an impact on Δ-RMST-based analysis regarding the probability of declaring equivalence. CONCLUSIONS: Although the RMST-based analysis is an alternative measure of efficacy in HIV/AIDS, clinical trials such an analysis can be strongly impacted by departures from the PH assumption.

Anti-gp41 antibody levels reflect HIV viral suppression and cellular reservoir in long-term antiretroviral-treated trial participants.

BACKGROUND: A major challenge to HIV cure strategies is the quantification of persistent reactivation-prone virus in people living with HIV. OBJECTIVES: To determine whether anti-gp41 antibody levels correlate with viral suppression and HIV-1 DNA levels in patients on ART. METHODS: Participants with plasma HIV-1 RNA below 50 copies/mL for >12 months were included from three ANRS cohorts (COPANA, MONOI and APROCO). Antibody levels to gp41 were measured by a low-sensitivity enzyme-linked immunoassay. Correlations with patient and virus characteristics, plasma HIV-1 RNA load (standard and ultrasensitive tests) and cell-associated HIV-1 DNA were assessed. RESULTS: Median age was 41 years and 77.5% of the 683 participants were men. Median CD4+ T cell count was 582 cells/mm3 and median viral suppression duration was 6.6 years (IQR 2.0-9.5). The overall median anti-gp41 antibody titre was 1.3 (IQR 0.6-1.9); median HIV-1 DNA level was 2.6 (IQR 2.1-3.0) log10 copies/106 leucocytes; and HIV-1 RNA was undetectable in 56% of samples. A lower titre of anti-gp41 antibodies correlated with male gender, longer viral suppression and lower HIV-1 DNA burden. Sustained undetectable HIV-1 RNA was associated with lower anti-gp41 levels [median 1.1 (IQR 0.5-1.6) versus 1.4 (IQR 0.7-1.9), P = 0.009]. CONCLUSIONS: Anti-gp41 levels decreased with the duration of antiviral suppression on ART. Lower titres were associated with lower HIV-1 DNA levels and longer duration of viral suppression, reflecting minimal antigen stimulation. Anti-gp41 antibody titration may be a useful biomarker reflecting long-term HIV-1 suppression on ART.

Ultrasensitive Human Immunodeficiency Virus Type 1 Viral Load as a Marker of Treatment Choice for Simplification Strategies.

Background: Using 3 randomized Protease inhibitor (PI) monotherapy studies: Kalesolo, Dream and Monoi, we performed a pooled-analysis. Our objective was to determine in PI monotherapy and standard tritherapy: 1) distribution of ultrasensitive viral load (USVL) at week 96 (W96); 2) factors associated with virological failure (VF) at W96 and 3) factors associated with USVL<1 copy at W96. Methods: VF was defined as 2 consecutive measurements of Human Immunodeficiency Virus Type 1 RNA viral load>50 copies/mL and analysed in Intention-To-Treat. A logistic model was used to investigate which variables were predictive of a VF and Fisher test to investigate differences in USVL at W96. Results: Among 609 patients, 73% were male with median age of 44.4 years (IQR 39.8-52.1), baseline CD4/CD8 ratio was 0.8 (IQR 0.6-1.10), baseline CD4 was 564.5/mm3 (IQR 422-707) and 59% presented a baseline USVL<1 copy/mL. At W96, the proportion of USVL<1 copy/mL was significantly different between PI monotherapy and standard tritherapy in pooled-analysis (65% versus 74%; p=0.04). Overall, baseline USVL<1copy/mL, tritherapy and to be a female were associated with USVL<1 copy/mL at W96 (p<0.0001, p=0.049 and p=0.006). In PI monotherapy receiving DRV/r was associated with USVL<1 copy/mL at W96 (p=0.003). Factors associated to virological succes at W96 were higher baseline CD4 (p=0.034) and baseline USVL<1 copy/mL (p=0.0005). Conclusion: Pooled-analysis of 3 PI monotherapy trials showed better efficacy of tritherapy in terms of USVL at W96. Furthermore regarding USVL at W96, to receive LPV/r seems to be more deleterious than DRV/r. Baseline USVL impacts VF at W96 more specifically in tritherapy arm. Clinical Trials Registration: NCT00421551, NCT00946595, and NCT00140751.

Choice of treatment-effect measures when noninferiority margins originally defined in absolute difference translated into relative difference influenced the results of clinical trials.

OBJECTIVES: The aim of this study was to investigate the use of three treatment-effect measures in the analysis of randomized trials using a time-to-event endpoint and assess their influence on the results. STUDY DESIGN AND SETTING: A recent equivalence trial showed discordant results with the use of different measures. Different hypotheses may explain such discordant results including a mistaken hypothesized distribution of time to failure and an overestimation of failure rates in the protocol. In a simulation study, we investigate different situations in comparing analyses based hazard ratio (HR), risk difference estimated by Kaplan-Meier curves, and difference in restricted mean survival time. We also compared these three analyses on genuine data from a recent equivalence trial. RESULTS: In the equivalence trial, two analyses would have concluded equivalence, whereas the original analysis based on HR estimate did not declare equivalence. Results of our simulation study indicate little to moderate differences between the three analyses when the true distribution of time to failure is different to the hypothesized distribution. The main discordant results are found when failure rates have been overestimated or underestimated regardless of the distribution. CONCLUSION: With the distributions investigated, differences between analyses based on different measures are much more driven by mistaken hypothesized failure rates than by the shape of the distribution of time to failure.

Antiretroviral therapy as a risk factor for chronic kidney disease: Results from traditional regression modeling and causal approach in a large observational study.

OBJECTIVE: We investigated whether patients receiving selected antiretroviral combinations had a higher risk of chronic kidney disease (CKD) using traditional regression modeling and a causal approach in a large prospective cohort. PATIENTS AND METHODS: For the purpose of this study, we selected 6301 patients who (i) started their first antiretroviral regimen after 1st January 2004, (ii) had at least one serum creatinine measurement within 6 months before ART initiation (study entry), and (iii) had at least two measurements after study entry. Baseline eGFR was defined from the last serum creatinine measurement before study entry. All eGFR values were calculated using the Modification of Diet and Renal Disease (MDRD) equation. Both traditional Cox proportional hazards model and Cox marginal structural models were applied. Distinct coding for antiretroviral therapy exposure were investigated as well as double robust estimators. RESULTS: Overall we showed that patients receiving tenofovir (TDF) with a ritonavir boosted protease inhibitor (rbPI) exhibited a higher risk of CKD compared with patients who received TDF with a non-nucleosidic reverse transcriptase inhibitor (NNRTI). Such an increased risk was observed considering both initial and current regimens. Our analysis revealed a clinician-driven switch away from TDF among persons experiencing a decline in renal function while receiving this drug. CONCLUSION: Our results show that combination of TDF and boosted protease inhibitor is associated with a higher CKD risk than TDF and a NNRTI.

Addition of Etravirine Does Not Enhance the Initial Decline of HIV-1 RNA in Treatment-Experienced Patients Receiving Raltegravir.

OBJECTIVE: The importance of an early reduction of HIV-1 RNA as a marker for positive longer term outcome is still under debate. We investigate whether antiretroviral-experienced patients receiving raltegravir plus etravirine have a higher early reduction of HIV-1 RNA compared with patients receiving raltegravir. DESIGN: An observational study of treatment-experienced patients. METHODS: The objective is to investigate 349 patients included in a raltegravir resistance study. The early outcome is defined as a reduction of HIV-1 RNA at week 8. The crude method defines all measurements below the limit of quantification to be equal to the limit of quantification provides biased estimates. Such a reduction is censored by the limit of quantification and is subject to selection bias in observational studies. RESULTS: The crude method showed a significant higher reduction in HIV-1 RNA reduction in patients receiving raltegravir plus etravirine compared with patients receiving raltegravir (mean reduction of 2.1 versus 1.8 log10 copies/mL). However, survival methods adjusted for both censoring, due to the limit of quantification, and confounding factors lead to a nonsignificant difference between the 2 treatment groups (mean reduction of 2.8 versus 2.7 log10 copies/mL). CONCLUSION: Taking into account censoring and confounding factors, our study did not demonstrate a higher early reduction of HIV-1 RNA in patients receiving raltegravir with versus without etravirine.

Accuracy of predictive ability measures for survival models.

One aspect of an analysis of survival data based on the proportional hazards model that has been receiving increasing attention is that of the predictive ability or explained variation of the model. A number of contending measures have been suggested, including one measure, R2 (ß), which has been proposed given its several desirable properties, including its capacity to accommodate time-dependent covariates, a major feature of the model and one that gives rise to great generality. A thorough study of the properties of available measures, including the aforementioned measure, has been carried out recently. In that work, the authors used bootstrap techniques, particularly complex in the setting of censored data, in order to obtain estimates of precision. The motivation of this work is to provide analytical expressions of precision, in particular confidence interval estimates for R2 (ß). We use Taylor series approximations with and without local linearizing transforms. We also consider a very simple expression based on the Fisher's transformation. This latter approach has two great advantages. It is very easy and quick to calculate, and secondly, it can be obtained for any of the methods given in the recent review. A large simulation study is carried out to investigate the properties of the different methods. Finally, three well-known datasets in breast cancer, lymphoma and lung cancer research are given as illustrations. Copyright © 2017 John Wiley & Sons, Ltd.