AIM: To compare histological endpoint assessment using noninvasive alternatives to biopsy during treatment in a chronic hepatitis C virus (HCV) cohort.

METHODS: Patients with chronic HCV were randomized to receive interferon-based therapy for 24 (genotypes 2/3) or 48 (genotype 1) wk. FibroSURE™ (FS) was assessed at baseline and at week-12 post-treatment follow-up. Baseline biopsy for METAVIR was assessed by a single pathologist. FibroScan^® transient elastography (TE) was performed during treatment in a patient subset.

RESULTS: Two thousand and sixty patients (n = 253 in Asia) were classified as METAVIR F0-1 (n = 1682) or F2-4 (n = 378). For F2-4, FS (n = 2055) had sensitivity and specificity of 0.87 and 0.61, respectively, with area under the receiver-operating curve of 0.82; corresponding values for TE (n = 214) and combined FS/TE (n = 209) were 0.77, 0.88 and 0.88, and 0.93, 0.68 and 0.88. Overall FS/TE agreement for F2-4 was 71% (κ = 0.41) and higher in Asians vs non-Asians (κ = 0.86 vs 0.35; P < 0.001). Combined FS/TE had 97% accuracy in Asians (n = 33). Baseline FS (0.38 vs 0.51, P < 0.001) and TE (8.0 kPa vs 11.9 kPa, P = 0.006) scores were lower in patients with sustained virological response than in nonresponders, and were maintained through follow-up.

CONCLUSION: FS and TE may reliably differentiate mild from moderate-advanced disease, with a potential for high diagnostic accuracy in Asians with chronic HCV.

Complications of chronic hepatitis C virus (HCV) infection occur as a consequence of progressive liver fibrosis, leading to cirrhosis, liver failure, and hepatocellular carcinoma. Histological assessment of liver injury and fibrosis is important for making treatment decisions, as well as for predicting prognosis and therapeutic outcome, in chronic liver disease[1]. Liver biopsy is, however, an invasive procedure, limited by issues relating to sampling, cost and morbidity, and only provides a static measure of fibrosis[2]. Accurate noninvasive methods of monitoring changes in fibrosis would be helpful in following the natural history of the disease and monitoring potential antifibrotic responses to antiviral or other treatment modalities. The past decade has seen the development of several noninvasive predictive indices for hepatic fibrosis based on direct and indirect serum markers, as well as imaging modalities to measure liver stiffness, such as transient elastography (TE) (FibroScan^®, Echosens, Paris, France)[3]. Serum HCV FibroSURE™ (FS) (Laboratory Corporation of America, Raritan, NJ, United States) combines α₂-macroglobulin, haptoglobin, γ-glutamyl transpeptidase, apolipoprotein A_1, alanine transaminase, and total bilirubin into a proprietary algorithm for fibrosis and inflammatory activity[4]. Both noninvasive modalities have been extensively evaluated in viral hepatitis and other chronic liver diseases[5]. The combination of serum tests, such as FS or FibroMeters, and TE appears to improve the cross-sectional diagnostic accuracy for advanced-stage disease in chronic HCV[6,7]. The French Haute Autorité de Santé has approved FS and TE as first-line tests to detect cirrhosis in chronic HCV[8]. Few studies, however, have determined the utility of either biomarkers or TE to accurately follow longitudinal changes in fibrosis both during and after antiviral therapy to better define long-term histological outcomes in chronic HCV[9-12]. Although there are emerging studies of TE in Asian patients with chronic liver disease (mostly due to chronic hepatitis B virus), no studies have evaluated the utility of both FS and TE in Asian patients with chronic HCV[13,14].

The aims of the present study were to: (1) compare the diagnostic utility of FS and TE for fibrosis at baseline in treatment-naïve patients with chronic HCV; (2) determine concurrent changes in both FS and TE with virological responses during and after albinterferon alfa-2b (albIFN) combination therapy; and (3) evaluate the performance of these noninvasive tests for the detection of significant fibrosis in an Asian cohort.

This large prospective cohort study in patients with chronic HCV provides validation of the diagnostic utility of serum markers and TE in relation to biopsy and IFN-based therapy. Few studies have addressed longitudinal changes in either serum markers or TE with therapy and, importantly, the present global study also provides the first evaluation of both noninvasive tests in patients from the Asia-Pacific region with chronic HCV. One limitation of this study was that TE data could only be obtained at 40 non-US study sites, as this device is not yet approved for use in the United States. Despite the limited cohort size for TE (n = 214) compared with FS (n = 2055), in accordance with prior observations, the overall results of this study indicate that both FS and TE have potential utility in the detection of moderate-severe-stage disease. However, the performance characteristics of these noninvasive tests (particularly TE) may be somewhat better for exclusion of cirrhosis[6,23]. For stages F2-4, FS and TE were effective in both Asian and NAR patients, but the agreement and accuracy of combined FS and TE were higher in the limited cohort of Asian patients with both tests (n = 33). Changes in FS and TE in relation to SVR were similar for both Asian and NAR patients.

This study shows that both pretreatment TE (n = 217) and FS (n = 2082) scores were lower in patients who achieved an SVR than in NRs, and that these differences were maintained through week 12 of therapy. Multivariate modeling indicated that older age and male sex (both predictive of lower virological responses in chronic HCV) were also independently associated with higher TE measurements at baseline. Other smaller studies, however, have failed to demonstrate similar baseline associations. A recent study from France evaluated TE and FS in 112 patients with chronic HCV receiving antiviral therapy, but did not include baseline biopsy or evaluation during therapy[11]. That study did not find any significant differences at baseline between patients with an SVR and NRs. Another study assessed TE alone before and after therapy in a Japanese chronic HCV cohort of 145 patients, and noted no differences at baseline between patients with an SVR and NRs[12]. Similar findings from another small French cohort evaluating TE alone have also been reported[24]. A recent meta-analysis of longitudinal studies in viral hepatitis indicated that both FS and TE could estimate treatment effect on fibrosis progression, although TE appeared to have early variability on treatment due to possible changes in necro-inflammatory activity[25]. The present study suggests that FS and TE could provide useful adjunctive information for the prediction of virological response prior to IFN-based therapy for chronic HCV. These noninvasive tests, however, likely reflect baseline differences in inflammatory response, but could complement established host-viral predictors of virological response to IFN-based therapy, such as HCV-RNA levels, viral Gt, race, and host IL28B polymorphism[26,27].

At follow-up, both FS and TE declined in patients who achieved an SVR. This is in accordance with prior observations that successful treatment with a biochemical response was associated with a decline in serum fibrosis marker indices or TE measurements in patients with chronic HCV[9-12,28,29]. A limitation of this study is that post-treatment biopsies were not required as part of these two clinical registration trials, which would have allowed for correlation between the observed declines in noninvasive test scores and changes in fibrosis or necro-inflammation. TE measurements may vary significantly with immune-mediated inflammatory responses in patients with chronic hepatitis B virus[30]. In contrast to other studies in patients with chronic HCV[6], however, this study also demonstrated a significant association between TE and histological necro-inflammatory activity at baseline. This association may have implications for establishing TE thresholds for different fibrosis stages in chronic HCV and may also explain the decline in liver stiffness measurements in patients with an established SVR in the present cohort. In this study, 80% of patients had no or mild fibrosis (stages F0-1) prior to treatment and thus were incapable of achieving a significant regression in fibrosis.

Both Asian and NAR cohorts demonstrated comparable performance characteristics for FS and TE. The observed accuracy and specificity for prediction of stages F2-4 in Asians, however, was higher in the small TE cohort. The combination of FS and TE in Asian patients resulted in a high accuracy for prediction of F2-4, with no false-positive results. Thus, biopsies for staging F2-4 could have been avoided in almost all Asian patients in this small cohort of 33 patients. There was excellent agreement between FS and TE in Asian patients, and this may partly relate to a slightly higher prevalence of advanced-stage disease and lower body mass index in the Asian cohort. Furthermore, increased waist circumference appears to be a common reason for failure of TE in European cohorts[19]. Although there are potential issues in obtaining adequate TE measurements in Asian patients due to a narrow intercostal space, this was not a limiting factor in the present study[13]. Thus, the combination of FS and TE in Asian patients with chronic HCV merits further evaluation.

One of the strengths of this study is that sample collections were standardized per protocol for the two phase III clinical trials, laboratory assessments were performed centrally, and all biopsies were evaluated by a single experienced liver histopathologist. Standardization significantly reduced the heterogeneity observed in prior studies comparing results across different geographic populations[23]. Biopsy sampling and observer error, however, are inherent limitations to the development and validation of all fibrosis biomarkers[31]. The experience of the pathologist may be more important than biopsy characteristics[32]. Furthermore, prior studies have indicated that the accuracy of liver biopsy (and noninvasive tests) is dependent on sample size[9,33-35]. In contrast to these prior observations, no significant change in the diagnostic accuracy of FS for stages F2-4 in > 900 patients with biopsies > 15 mm was found in the present study. Of note, TE accuracy for F2-4 appeared to decline in > 80 patients with this optimal biopsy length, although only 19 with biopsy F2-4 were in this cohort.

Prior studies have suggested that noninvasive performance indices for stages F2-4 and F4 are improved using sequential algorithms of FS and TE[6], or aspartate aminotransferase-to-platelet ratio index and FS[36]. In the present study, the F2-4 results for combined FS and TE indicated a comparable AUROC and agreement (0.88 and 71%, respectively) to those observed in a recent study from France in 302 patients with chronic HCV (0.91 and 72%, respectively) with a higher prevalence of advanced-stage disease[37]. Although discordance rates between sequential FS and TE with biopsy were not reported in the French study, prior data from that cohort indicated 84% concordance between biopsy and FS/TE agreement. This observation is similar to the 86% agreement noted in the present study; however, in contrast to the French cohort, cases of discordance between biopsy and FS/TE agreement were due to false positives with the noninvasive tests. In practical terms, agreement between FS and TE regarding prediction of F2-4 in the present study cohort could have avoided 71% of biopsies, although 10% of patients would still have been misclassified as having significant fibrosis. The discordance rate between FS and TE was 29%, with biopsy and TE agreement in most of the cases that appeared to have mild-stage disease. As expected, misclassification rates and discordance between FS and TE with biopsy were significantly reduced for prediction of F4.

With a broader range of available therapeutic options for patients with chronic HCV in the future, noninvasive measures that can accurately exclude advanced-stage disease will likely assume a more significant clinical role in the treatment decision process. Recent mathematical modeling indicates that a perfect biomarker of stages F2-4 may not exceed an AUROC of 0.9[38], and thus various issues regarding biopsy sampling error and noninvasive test discordance should be individualized when using these tests to predict a threshold of F2 in clinical practice. The observed heterogeneity among studies (including the present one) for optimized TE cutoffs indicates that a range of liver stiffness measurements for each fibrosis threshold in patients with chronic HCV may be more appropriate[39]. Standardization of AUROC curves or other methods to reduce effects of spectrum bias in disease prevalence allows for comparison of FS across studies, including selected cohorts within studies, but not for TE due to variable optimal thresholds[21]. No significant differences between observed and standardized AUROC values were found in the present study for either noninvasive measure.

In summary, this study demonstrates that a combination of serum and imaging noninvasive tests can be used for prediction of at least moderate-stage disease in a global cohort of patients with chronic HCV, including the potential of higher accuracy for the combination of FS and TE in Asian patients. Furthermore, some baseline differences in index values for both FS and TE were dependent on virological response and merit further evaluation in the context of IFN-based therapy.

Marx G of BioScience Communications, New York, NY, United States, provided editorial assistance, supported by Human Genome Sciences and Novartis Pharma AG. The authors also wish to thank all research staff and technicians who participated in this study.

ACHIEVE-1 investigators: Benhamou Y, Hôpital Pitié-Salpêtrière, Paris, France; Berg T, University Hospital Charite Berlin/Virchow Klinikum, Berlin, Germany; Bourliere M, Hopital Saint-Joseph, Marseille, France; Chang TT, National Cheng Kung University Hospital, Tainan, Taiwan, China; Couzigou P, Hopital Haut-Leveque, Pessac, France; Davis G, Baylor University Medical Center, Dallas, TX, United States; Encke J, Universitätsklinikum Heidelberg, Germany; Forns X, Hospital Clinic i Provincial, Barcelona, Spain; Gerken G, University Hospital of Essen, Germany; Ghalib R, Liver Institute at Methodist Dallas, Texas; Gladysz A, Przychodnia przy Łowieckiej, Wrocław, Poland; Grigorescu M, Spitalul Clinic de Urgenta, Cluj-Napoca, Romania; Häussinger D, Universitätsklinik Düsseldorf, Germany; LurieY, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel; Manns M, Medizinische Hochschule Hannover, Germany; Marcellin P, Hopital Beaujon, Clichy, France; Moreno R, Hospital Universitario La Princesa, Madrid, Spain; Pawlotsky JM, Hopital Henri Mondor, Creteil, France; Plisek S, Klinika Infekcních Nemocí, Hradec Kralove, Czech Republic; Poupon R, Hôpital Saint-Antoine, Paris, France;

Rodriquez-Torres M, Fundacion de Investigacion de Diego, Santurce, Puerto Rico; Safadi R, Holy Family Hospital, Nazareth, Israel; Schiff E, University of Miami, Florida, United States; Stanciu C, Institutul de Gastroenterologie si Hepatologie, Iasi, Romania; Trepo C, CHU de Lyon, Hôpital de l’Hôtel Dieu, France; Zeuzem S, J.W. Goethe University Hospital, Frankfurt, Germany.

ACHIEVE-2/3 investigators: Baruch Y, Rambam Health Care Campus, Haifa, Israel; Benhamou Y, Hopital Pitie-Salpetriere, Paris, France; Berg T, University Hospital Charite Berlin/Virchow Klinikum, Germany; Bourliere M, Hopital Saint-Joseph, Marseille, France; Bronowiki JP, Hôpital de Brabois, Vandoeuvre, France; Lee CM, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Chang Gung University College of Medicine, Kaohsiung, Taiwan; Cho M, Pusan National University Hospital, Busan, South Korea; Colle I, Ghent University Hospital, Ghent, Belgium; Delwaide J, CHU Sart Tilman, Liège, Belgium; Encke J, Universitätsklinikum Heidelberg, Germany; Gerken G, University Hospital Essen, Germany; Han KH, Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea; Häussinger D, Universitätsklinik Düsseldorf, Germany; Lee KS, Yongdong Severance Hospital, Seoul, South Korea; Langlet P, CHU Brugmann ULB-Site Victor Horta, Brussels, Belgium; Manns M, Medizinische Hochschule Hannover, Germany; Marcellin P, Hopital Beaujon, Clichy, France; Michielsen P, University Hospital Antwerp, Edegem, Belgium; Pawlotsky JM, Hopital Henri Mondor, Creteil, France; Poupon R, Hôpital Saint-Antoine, Paris, France; Schiff E, University of Miami, Florida; Trepo C, CHU de Lyon, Hôpital de l’Hôtel Dieu, France; Tur Kaspa R, Rabin Medical Center Beilinson Hospital, Petach Tikva, Israel; Um SH, Korea University Medical Center, Anam Hospital, Seoul, South Korea; Zeuzem S, J.W. Goethe University Hospital, Frankfurt, Germany.