Comparison of the Abbott RealTime HCV and Roche COBAS Ampliprep/COBAS TaqMan HCV assays for the monitoring of sofosbuvir-based therapy

Does a detectable HCV RNA at the end of DAA therapy herald treatment failure?

BACKGROUND & AIMS

The study aimed to assess the phenomenon of achieving sustained virologic response (SVR) in patients with detectable ribonucleic acid (RNA) of hepatitis C virus (HCV) at the end of treatment (ET) with direct-acting antivirals (DAA), find how this is affected by the type of regimen, and how patients experiencing this differed from non-responders with detectable HCV RNA at the ET.

METHODS

The study included all consecutive patients with detectable HCV RNA at the ET selected from the EpiTer-2 database, a retrospective national multicentre project evaluating antiviral treatment in HCV-infected patients in 2015-2023.

RESULTS

Of the 16106 patients treated with IFN-free regimens with available HCV RNA assessment at the ET and at follow-up 12 weeks after treatment completion (FU), 1253 (7.8%) had detectable HCV RNA at the ET, and 1120 of them (89%) finally achieved SVR. This phenomenon was significantly more frequent in pangenotypic regimens, 10.3% vs. 4.7% in genotype-specific options (p < 0.001), and the highest proportion was documented for glecaprevir/pibrentasvir (13.7%), and velpatasvir/sofosbuvir ± ribavirin (6.9%). Patients ET + FU- treated with these two pangenotypic regimens (n = 668) had less advanced liver disease, were less frequently infected with genotype (GT) 3, and were significantly more likely to be treatment-naïve than 61 non-responders.

CONCLUSIONS

We documented 7.8% rate of patients with detectable HCV RNA at the ET, of whom 89% subsequently achieved SVR, significantly more frequently in the population treated with pangenotypic regimens. Less severe liver disease, more often GT3 infection, and a higher percentage of treatment-naive patients distinguished this group from non-responders.

Short-term histological evaluations after achieving a sustained virologic response to direct-acting antiviral treatment for chronic hepatitis C

BACKGROUND

Interferon-free, direct-acting antiviral treatments can result in a sustained virologic response in nearly 100% of patients with chronic hepatitis C virus infection.

AIMS

The purpose of this study was to evaluate histological improvement after achieving a sustained virologic response to direct-acting antiviral treatments in patients with chronic hepatitis C.

METHODS

Among 691 patients with chronic hepatitis C who achieved a sustained virologic response to direct-acting antivirals, 51 underwent liver biopsy 41 ± 20 weeks after the end of treatment despite normal transaminase levels. In 20 patients, liver biopsy specimens obtained a median of 1.2 years before the start of treatment were available.

RESULTS

Among the 51 patients who underwent post-sustained virologic response biopsies, the grade of inflammation was A0 in 18 patients, A1 in 24, A2 in eight, and A3 in one; the stage of fibrosis was F0 in three patients, F1 in 20, F2 in 15, F3 in nine, and F4 in four. Among the nine post-sustained virologic response biopsy specimens with moderate-to-severe inflammation (≥A2), four showed S1-to-S3 steatosis (>5% of hepatocytes affected). In the 20 paired biopsy specimens, the inflammation grade significantly regressed (p = 0.0043), but the fibrosis stage did not (p = 0.45). Histological improvement, defined as a ≥ 2-point decrease in the Knodell inflammatory score and no worsening of the fibrosis, was found in 11 (55%) patients. The iron accumulation had significantly regressed (p = 0.0093), but the steatosis had not (p = 0.10).

CONCLUSIONS

Even if transaminases become normal after obtaining a sustained virologic response, significant histological inflammation of unknown cause was found in some patients. Additionally, improvement in liver fibrosis was not evident in the short term.

Significance of day-1 viral response of hepatitis C virus in patients with chronic hepatitis C receiving direct-acting antiviral therapy

BACKGROUND AND AIM

On-treatment response of serum hepatitis C virus (HCV) is reportedly less useful to predict the outcome of anti-HCV therapy with interferon (IFN)-free regimen with direct-acting antivirals than with IFN-based regimens in clinical trials. We evaluated the significance of very early viral response after the start of therapy, which indicates direct HCV response to the drugs, on therapeutic outcome.

METHODS

Reductions in serum HCV-RNA levels were measured at 1 day after the start of therapy in 544 patients who underwent IFN-free direct-acting antiviral regimens. The association between these reductions and the achievement or failure of sustained virologic response (SVR) was evaluated.

RESULTS

Patient characteristics did not influence 1-day reduction in serum HCV-RNA except for liver fibrosis. There was no difference in 1-day HCV reduction between SVR and non-SVR patients treated with a 24-week regimen. In contrast, in patients treated with a 12-week regimen, 1-day reduction was significantly greater in SVR than in non-SVR patients (P = 0.0013) and was predictive of SVR versus non-SVR (area under the receiver-operating characteristics curve: 0.80).

CONCLUSIONS

Whereas the reduction in serum HCV-RNA levels at 1 day after the start of therapy was not associated with treatment outcomes in patients who underwent a 24-week regimen of IFN-free therapy, there was an association in patients receiving a 12-week regimen, and this reduction was predictive of SVR, thus potentially serving as a factor to identify patients at risk of treatment failure.

Significance of detectable HCV RNA below the limit of quantification in patients treated with DAAs using standard and ultrasensitive protocols

Predictive factors of HCV relapse after treatment with DAAs are poorly understood. In this study, we aimed to assess whether the residual viral load positivity observed during or at the end of treatment (EOT) has an impact on viral outcome. Blood samples were collected from 337 patients with genotypes (GT) 1a, 1b, 2, 3, and 4 HCV chronic infection, treated with DAAs to determine HCV RNA load by the Abbott RealTime HCV (ART) assay at treatment week (W) 4, at EOT, and 4, 12, 24 weeks after discontinuation. EOT and other samples with "detected <12/mL" (DNQ) were retested by an ultrasensitive protocol (USP) to confirm the result. Frequency of DNQ was analyzed in subgroups of patients and clinical conditions to assess potential correlations. At W4, 22% and 30.9% of the samples were undetectable and DNQ by ART assay, respectively, but no correlation for achieving SVR was found. In contrast, an HCV RNA cut-off of ≥50/mL at W4 was a significant predictor of therapy failure (P = 0.036, univariate analysis). At EOT, DNQ was associated to 12W treatment duration (P < 0.001) and GT1a infection (P = 0.036). Overall, 20/41 (48.8%) of DNQ samples at EOT or post-treatment W4, were confirmed by USP but only in a single case the patient experienced viral relapse. HCV RNA at W4 can predict SVR, irrespective to genotype or DAA regimen. HCV RNA DNQ at EOT is associated to shorter treatment duration and to GT1a, but is not a predictor of therapy failure.

Implications of HCV RNA level at week 4 of direct antiviral treatments for hepatitis C

We aimed to determine whether the HCV viral load after four weeks of treatment (W4VL) with direct-acting antiviral agents (DAAs) predicts sustained virologic response (SVR) in a real-world clinical setting. We identified 21 095 patients who initiated DAA-based antiviral treatment in the national Veterans Affairs (VA) healthcare system from 01/01/2014 to 06/30/2015. Week 4 viral load was categorized as undetectable, detectable below quantification (DBQ), detectable above quantification (DAQ) with viral load ≤42 IU/mL and DAQ with viral load >42 IU/mL. Week 4 viral load was undetectable in 36.1%, detectable below quantification in 45.6%, DAQ ≤42 in 9.3%, DAQ >42 in 9.1%. Detectable above quantification was much more common and undetectable week 4 viral load much less common when tested with the Abbott RealTime HCV assay vs the Roche COBAS AmpliPrep/COBAS TaqMan Version 2 assay. Compared to patients with undetectable week 4 viral load (SVR=93.5%), those with detectable below quantification (SVR=91.8%, adjusted odds ratio [AOR] 0.79, P-value=.001), DAQ ≤42 (SVR=90.0%, AOR 0.63, P-value<.001) and DAQ >42 (SVR=86.2%, AOR 0.52, P-value<.001) had progressively lower likelihood of achieving SVR after adjusting for baseline characteristics and treatment duration. Among genotype 1-infected patients who were potentially eligible for 8-week sofosbuvir/ledipasvir monotherapy, we did not find evidence that treatment for 12 weeks instead of 8 weeks was associated with higher SVR, even among those with detectable above quantification. In summary, DBQ and DAQ W4VL are very common in real-world practice, contrary to what was reported in clinical trials, and strongly predict reduced SVR across genotypes and clinically relevant patient subgroups. Whether and how week 4 viral load results should influence treatment decisions requires further study.

Comparison of on-treatment HCV RNA during direct antiviral therapy using two different COBAS TaqMan HCV assays

BACKGROUND

Repeated measurements of hepatitis C virus (HCV) RNA levels during antiviral therapy are recommended to monitor treatment efficacy and adherence. Throughout most direct antiviral agent (DAA) approval studies, HCV RNA cutoffs and endpoints were established with the COBAS TaqMan assay for use with the High Pure System (HPS/CTM). Different assays used in clinical practice may yield different quantitative results and possibly impact treatment decisions.

OBJECTIVES

The concordance of the fully-automated COBAS AmpliPrep/COBAS TaqMan assay (CAP/CTM) with HPS/CTM and its ability to predict response to DAA-treatment with ledipasvir/sofosbuvir was assessed in cirrhotic patients with HCV genotype-1-infection who had failed prior treatment with protease inhibitor-based regimens.

STUDY DESIGN

Serum samples from patients (n=154) treated in the phase-2 SIRIUS-study were collected at baseline and during antiviral therapy (weeks 1-8), and were tested in parallel by both assays.

RESULTS

The mean difference between HPS/CTM and CAP/CTM at baseline (n=153) was 0.32 log₁₀ IU/mL HCV RNA. Discordant results were observed in 12% of samples collected at treatment weeks 1-8, with the greatest differences observed at weeks 2 and 4 (14% and 29%, respectively, for undetectable HCV RNA). SVR rates were 96%-97% in the study and were not significantly different between patients with detectable vs. undetectable HCV RNA according to both assays at weeks 1-4 of antiviral therapy.

CONCLUSIONS

CAP/CTM and HPS/CTM showed significantly different response rates during the early stages of ledipasvir/sofosbuvir treatment. However, on-treatment response was not predictive of SVR with either assay, indicating that determination of on-treatment HCV RNA levels may not be useful to guide treatment decisions.

Effectiveness and safety of sofosbuvir plus ribavirin for HCV genotype 2 patients 65 and over with or without cirrhosis

Older patients with chronic hepatitis C virus (HCV) infection have historically been designated difficult-to-treat. We evaluated the efficacy and safety of sofosbuvir (nucleotide NS5B polymerase inhibitor) plus ribavirin for patients with HCV genotype 2 infection in a real-world clinical setting, with the focus on elderly patients aged ≥ 65. This large, multicenter study consisted of 446 Japanese HCV genotype 2 patients (303 treatment-naïve and 143 treatment-experienced), including 190 (42.6%) aged ≥ 65 and 90 (20.2%) with compensated cirrhosis. Efficacy was assessed by the sustained virological response 12 weeks post-treatment (SVR12). The overall SVR12 rate was 95.7% (427/446), and the SVR12 rate of patients aged ≥ 65 was 95.3% (181/190). For treatment-naïve patients, almost all with compensated cirrhosis (95.6%, 43/45) achieved SVR12, irrespective of age. For treatment-experienced patients, cirrhosis undermined the treatment outcome, both for the aged ≥65 (SVR12: 80.0%, 20/25) and <65 (85.0%, 17/20) patient groups when compared to non-cirrhosis patients (≥65: 95.7%, 45/47 and < 65: 96.2%, 50/52). The most common adverse effect was anemia (hemoglobin <10 g/dL), especially for patients aged ≥ 65 with the inosine triphosphate pyrophosphatase CC genotype at rs1127354 (26.2%, 33/126). Notably, ribavirin reduction was not related to treatment failure. Only three (0.7%) patients, all aged ≥ 65, discontinued treatment, but all achieved SVR12. Sofosbuvir plus ribavirin for HCV genotype 2 was effective for patients aged ≥65, especially those who were treatment-naïve or treatment-experienced/non-cirrhosis.