Performance assessment of the new Xpert® HIV-1 viral load XC assay for quantification of HIV-1 viral loads.

Background: HIV-1 RNA quantification is a key component of treatment monitoring.

Objectives: To assess the performance of a redesigned HIV-1 RNA quantitative assay that uses a dual-target approach: Xpert® HIV-1 Viral Load (VL) XC.

Study Design: Fresh and frozen samples (N = 533) from HIV-1 positive patients tested with Abbott HIV-1 assays (Alinity m and RealTime [m2000]) were retested using the new Xpert XC assay.

Clinical evaluation of the automated Abbott RealTime SARS-CoV-2, Alinity m SARS-CoV-2, and Alinity m Resp-4-Plex assays.

Background: Detection of SARS-CoV-2 infections relies on the use of sensitive, accurate and high throughput RT-PCR assays.

Objectives: We assessed the analytical performance of the Abbott RealTime SARS-CoV-2 (RT-SARS), Alinity m SARS-CoV-2 (AlinSARS) assays and compared the clinical performance of the RT-SARS, AlinSARS, and Alinity m Resp-4-Plex (Alin4Plex) assays to the Seegene Allplex assay (Allplex) and an inhouse test (Inhouse).

Results: We found 100 % positive percent agreement (PPA) and 100 % negative percent agreement (NPA) comparing RT-SARS and Allplex.

Multicenter clinical evaluation of alinity m HCV assay performance.

Background: Nucleic acid testing is essential for the detection and quantification of HCV RNA in the diagnosis of HCV infection and treatment monitoring. The Alinity m HCV assay was recently developed by Abbott Molecular for rapid detection and quantification of HCV RNA on the fully automated, continuous, random-access Alinity m analyzer.

Objectives: Our study assessed the performance of the new Alinity m HCV assay for detection and quantification of HCV RNA in a large series of patient samples of various genotypes.

Multicenter clinical comparative evaluation of Alinity m HIV-1 assay performance.

Background: Accurate, rapid detection of HIV-1 RNA is critical for early diagnosis, treatment decision making, and long-term management of HIV-1 infection.

Objective: We evaluated the diagnostic performance of the Alinity m HIV-1 assay, which uses a dual target/dual probe design against highly conserved target regions of the HIV-1 genome and is run on the fully automated Alinity m platform.

Study Design: This was an international, multisite study that compared the diagnostic performance of the Alinity m HIV-1 assay to four commercially available HIV-1 assays routinely used in nine independent clinical laboratories.

Multicenter clinical evaluation of alinity m HBV assay performance.

Background: Accurate molecular methods to detect and quantify hepatitis B virus (HBV) DNA are essential to diagnose chronic infections, guide treatment decisions, assess response to treatment, and determine risk of HBV-related complications. New generations of real-time HBV DNA assay platforms provide results in less than 2-3 h, with continuous loading of specimens and true random-access capability.

Objectives: We examined the clinical performance of the new Alinity m HBV assay, run on the fully automated, continuous, random-access Alinity m platform, to accurately detect and quantify HBV DNA in a large series of patient samples infected with different HBV genotypes frequently encountered in clinical practice.

Comparison of two immunoassays for concurrent detection of HCV antigen and antibodies among HIV/HCV co-infected patients in dried serum/plasma spots.

Hepatitis C virus (HCV) antigen/antibody (Ag/Ab) assays offer the benefit of reducing the window period compared to assays that detect only HCV-Ab. In this study the performance of the Murex Ag/Ab (Murex, Abbott) and Monolisa Ag/Ab Ultra (Monolisa, Bio-Rad) ELISAs was compared for the use of filter dried serum/plasma spots (DS/PS) with a focus on the sensitivity and the percentage of correct positive test results. Correct positive ELISA results were assumed for samples that subsequently tested positive for HCV RNA by RT-qPCR, or RNA negative samples that tested positive in a Western blot (confirmed ELISA results).

Establishment of an anti-hepatitis C virus IgG avidity test for dried serum/plasma spots.

Monitoring recency of infection helps to identify current transmission in vulnerable populations for effective disease control. We have established an in-house avidity based hepatitis C virus (HCV) recency assay based on the Monolisa Anti-HCV PLUS Version 3 ELISA kit for use of dried serum/plasma spots (DS/PS) in order to distinguish recent and long-term infections. A first panel of DS/PS (n = 218; genotype 1 n = 170 and non-genotype 1 n = 48) consisting of primary and at least one follow up sample was used to analyze the temporal changes of the Avidity Index (AI) over time.

Multicenter Evaluation of Two Next-Generation HIV-1 Quantitation Assays, Aptima Quant Dx and Cobas 6800, in Comparison to the RealTie HIV-1 Reference Assay.

High accuracy and precision at the lower end of quantification are crucial requirements of a modern HIV viral load (VL) assay, since some clinically relevant thresholds are located at 50 and 200 copies/ml. In this study, we compared the performance of two new fully automated HIV-1 VL assays, Aptima HIV-1 Quant Dx and Cobas HIV-1 (Cobas 6800), with the established RealTie 2000 assay. Assay precision and accuracy were evaluated in a retrospective evaluation out of excess plasma material from four HIV-1+ individuals (subtypes B, C, CRF01_AE, and CRF02_AG).

HIV-1 persistent viremia is frequently followed by episodes of low-level viremia.

After the start of antiretroviral therapy (ART), plasma HIV-RNA levels should fall below the limit of detection (LOD) within 24 weeks. Hence, the prolonged decline of HIV-RNA after ART initiation is defined as persistent viremia (PV). In this retrospective study, we analyzed factors associated with PV.

Resistance remains a problem in treatment failure.

Introduction: Proven resistance against HIV drugs, either by phenotyping or genotyping is a rare event in clinical trials. The overall assumption of drug resistance disappearing is additionally driven by the recommendations to screen for transmitted drug resistance, leading to large numbers of examinations with relatively low rates of resistance. Goal of our analysis was to assess if drug resistance in treatment failure is also decreasing outside of clinical trials.

New dolutegravir resistance pattern identified in a patient failing antiretroviral therapy.

Introduction: The most recently approved antiretroviral, the integrase inhibitor dolutegravir (DTG), is described to be a very potent drug with a unique resistance profile, but a certain degree of cross-resistance to RAL or EVG induced drug resistance, which is mediated mainly by integrase mutations at positions 140 and 148. The impact of a single N155H mutation to DTG resistance is described to be minor. However, there is only rare data available about the impact of N155H in the context of secondary site integrase mutations.

Appearance of NS3 Q80K mutation in HCV genotype 1a mono- or HIV/HCV co-infected patients in a Berlin laboratory.

Introduction: Simeprevir, a new oral NS3/4A protease inhibitor, was recently approved by the FDA and the EMA for the treatment of patients with chronic HCV genotype 1, 4, 5 and 6 infection l. It has been recommended in the 2014 UK Consensus Guidelines as a possible treatment of previously untreated genotype 1a-infected patients. The antiviral efficacy of simeprevir is adversely affected by the mutation at the Q80K loci.

Safety analysis of raltegravir/truvada regimen in HIV/HCV co-infected patients without switchback after HCV treatment.

Introduction: Due to drug-drug interactions of HIV- and HCV-specific antivirals when initiating an HCV-therapy, the antiretroviral therapy (ART) often has to be changed. The spectrum of applicable antiretrovirals is small, therefore many patients were switched to raltegravir/truvada (RAL/TVD) in our cohort. Due to the relatively low genetic barrier of RAL, this regimen may be endangered to fail, if the NRTI backbone is not fully active because of pre-existing NRTI resistance.

Comparison of HIV-1 viral load assay performance in immunological stable patients with low or undetectable viremia.

The goal of antiretroviral therapy is reduction in morbidity and mortality via suppression of human immunodeficiency virus (HIV) viral load (VL) to undetectable levels. VL assay sensitivity has improved over time, but the reproducibility and clinical importance of VL results marginally higher than the limit of detection (LoD) are uncertain. We assessed the reproducibility and concordance of low VL results obtained with the Roche Cobas AmpliPrep/Cobas TaqMan HIV-1 version 2.

HIV-GRADE: a publicly available, rules-based drug resistance interpretation algorithm integrating bioinformatic knowledge.

Background: Genotypic drug resistance testing provides essential information for guiding treatment in HIV-infected patients. It may either be used for identifying patients with transmitted drug resistance or to clarify reasons for treatment failure and to check for remaining treatment options. While different approaches for the interpretation of HIV sequence information are already available, no other available rules-based systems specifically have looked into the effects of combinations of drugs.

The L76V mutation in HIV-1 protease is potentially associated with hypersusceptibility to protease inhibitors Atazanavir and Saquinavir: is there a clinical advantage?

Background: Although being considered as a rarely observed HIV-1 protease mutation in clinical isolates, the L76V-prevalence increased 1998-2008 in some European countries most likely due to the approval of Lopinavir, Amprenavir and Darunavir which can select L76V. Beside an enhancement of resistance, L76V is also discussed to confer hypersusceptibility to the drugs Atazanavir and Saquinavir which might enable new treatment strategies by trying to take advantage of particular mutations.

Results: Based on a cohort of 47 L76V-positive patients, we examined if there might exist a clinical advantage for L76V-positive patients concerning long-term success of PI-containing regimens in patients with limited therapy options.

Prevalence of key resistance mutations K65R, K103N, and M184V as minority HIV-1 variants in chronically HIV-1 infected, treatment-naïve patients.

Background And Objectives: Minority drug-resistant HIV-1 variants, undetected by conventional genotyping, may impair the outcome of antiretroviral therapy (ART). Thus, we retrospectively analyzed the prevalence of minority drug-resistant HIV-1 variants before ART in chronically HIV-1 infected patients initiating first-line therapy and assessed the impact on clinical outcome in the prospective German Truvada cohort.

Study Design: Samples from 146 antiretroviral treatment-naïve patients were collected between April 2005 and August 2006.

Comparison of four commercial quantitative HIV-1 assays for viral load monitoring in clinical daily routine.

Background: Quantification of viral load (VL) is standard for monitoring HIV-1 therapy and is crucial before deciding whether to switch or to continue a current antiretroviral regimen.

Methods: We compared the performance of the four most widely used commercial viral-load assays, COBAS Amplicor Monitor v1.5, Versant HIV-1 RNA 3.