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Utility of the new cobas HCV test for viral load monitoring during direct-acting antiviral therapy
(2019)
Background: The COBAS AmpliPrep/COBAS TaqMan assay HCV (CAP/CTM) is widely used in clinical routine for HCV testing. Recently, the new cobas HCV test was established for high throughput testing with minimal operator intervention. As different assays may yield different quantitative/qualitative results that possibly impact treatment decisions, the aim of this study was to externally evaluate the cobas HCV test performance in comparison to CAP/CTM in a clinically relevant setting.
Methods: Serum samples were obtained from 270 patients who received direct acting antiviral therapy with different treatment regimens at two study sites (Hannover and Frankfurt) in 2016. Overall, 1545 samples (baseline, on-treatment and follow-up) were tested in parallel by both assays.
Results: The mean difference between cobas HCV and CAP/CTM for the quantification of HCV RNA was 0.008 log10 IU/ml HCV RNA (95% limits of agreement: -0.02–0.036) showing excellent agreement of both assays. With respect to clinical cut offs (HCV RNA detectable vs. target not detected and HCV RNA above the lower limit of quantification (LLOQ) vs. <LLOQ), discordant results were obtained in 9.5% and 4.6%, respectively; the greatest differences were observed during early stages of antiviral therapy (week 1, week 2 and week 4), but none were statistically significant. Overall percent agreement for SVR between cobas HCV and CAP/CTM at the 15 IU/ml cutoff was 99.2% (95%CI 92.7%-100%).
Conclusion: The performance of the new cobas HCV test was comparable to CAP/CTM in a clinical setting representing a large patient population with HCV GT 1 and 3 treated with DAAs.
Protease inhibitors (PIs) are important components of treatment regimens for patients with chronic hepatitis C virus (HCV) infection. However, emergence and persistence of antiviral resistance could reduce their efficacy. Thus, defining resistance determinants is highly relevant for efforts to control HCV. Here, we investigated patterns of PI resistance–associated substitutions (RASs) for the major HCV genotypes and viral determinants for persistence of key RASs. We identified protease position 156 as a RAS hotspot for genotype 1‐4, but not 5 and 6, escape variants by resistance profiling using PIs grazoprevir and paritaprevir in infectious cell culture systems. However, except for genotype 3, engineered 156‐RASs were not maintained. For genotypes 1 and 2, persistence of 156‐RASs depended on genome‐wide substitution networks, co‐selected under continued PI treatment and identified by next‐generation sequencing with substitution linkage and haplotype reconstruction. Persistence of A156T for genotype 1 relied on compensatory substitutions increasing replication and assembly. For genotype 2, initial selection of A156V facilitated transition to 156L, persisting without compensatory substitutions. The developed genotype 1, 2, and 3 variants with persistent 156‐RASs had exceptionally high fitness and resistance to grazoprevir, paritaprevir, glecaprevir, and voxilaprevir. A156T dominated in genotype 1 glecaprevir and voxilaprevir escape variants, and pre‐existing A156T facilitated genotype 1 escape from clinically relevant combination treatments with grazoprevir/elbasvir and glecaprevir/pibrentasvir. In genotype 1 infected patients with treatment failure and 156‐RASs, we observed genome‐wide selection of substitutions under treatment. Conclusion : Comprehensive PI resistance profiling for HCV genotypes 1‐6 revealed 156‐RASs as key determinants of high‐level resistance across clinically relevant PIs. We obtained in vitro proof of concept for persistence of highly fit genotype 1‐3 156‐variants, which might pose a threat to clinically relevant combination treatments.
Background: Accurate assessment of hepatic fibrosis in patients with chronic HBeAg-negative Hepatitis B is of crucial importance not only to predict the long-term clinical course, but also to evaluate antiviral therapy indication. The aim of this study was to prospectively assess the utility of point shear wave elastography (pSWE) for longitudinal non-invasive fibrosis assessment in a large cohort of untreated patients with chronic HBeAg-negative hepatitis B virus (HBV) infection.
Methods: 407 consecutive patients with HBeAg-negative HBV infection who underwent pSWE, transient elastography (TE) as well as laboratory fibrosis markers, including fibrosis index based on four factors (FIB-4), aspartate to platelet ratio index (APRI) and FibroTest, on the same day were prospectively followed up for six years. Patients were classified into one of the three groups: inactive carriers (IC; HBV-DNA <2000 IU/mL and ALT <40 U/L); grey zone group 1 (GZ-1; HBV DNA <2000 IU/mL and ALT >40 U/L); grey zone group 2 (GZ-2; HBV-DNA >2000 IU/mL and ALT <40 U/L).
Results: pSWE results were significantly correlated with TE (r = 0.29, p < 0.001) and APRI (r = 0.17; p = 0.005). Median pSWE values did not differ between IC, GZ-1 and GZ-2 patients (p = 0.82, p = 0.17, p = 0.34). During six years of follow-up, median pSWE and TE values did not differ significantly over time (TE: p = 0.27; pSWE: p = 0.05).
Conclusion: Our data indicate that pSWE could be useful for non-invasive fibrosis assessment and follow-up in patients with HBeAg-negative chronic HBV infection.